Vulnerability to Climate Change of Australia s Coastal Zone: Analysis of gaps in methods, data and system thresholds

Transcription

1 Vulnerability to Climate Change of Australia s Coastal Zone: Analysis of gaps in methods, data and system thresholds Editors: M. Voice, N. Harvey and K. Walsh Report to the Australian Greenhouse Office, Department of the Environment and Heritage 2006

2 Preferred way to cite this publication: Voice, M., Harvey, N. and Walsh, K. (2006). (Editors) Vulnerability to Climate Change of Australia s Coastal Zone: Analysis of gaps in methods, data and system thresholds. Report to the Australian Greenhouse Office, Canberra, Australia. June Contributing authors by alphabetical order and subject matter: Jacqueline Balston, Emerging Technologies, Department of Primary Industries and Fisheries, Queensland (Fisheries and Aquaculture) Captain Kerry Dwyer, K. Dwyer & Associates Pty Ltd, NSW. Chris Harty, Chris Harty Planning and Environmental Management, Camperdown, Victoria (Estuaries, Planning) Nick Harvey, Professor, Geography and Environmental Studies, The University of Adelaide (Beaches, Estuaries, Coastal Ecosystems) John Holmes, JDH Consulting, Mentone Victoria (Infrastructure) Janice Lough, Australian Institute of Marine Science, Townsville, Queensland (Corals, Coral Reefs and Communities, Coastal Ecosystems) Catherine Lovelock, Centre for Marine Studies/School of Integrative Biology, University of Queensland (Mangroves) Steve Oliver, Global Environmental Modelling Systems Pty Ltd (Coastal Infrastructure) Peter Riedel, Coastal Engineering Solutions (Coastal Infrastructure) Mary Voice, Cumulus Consulting, Melbourne, Victoria (Selected other coastal activities) Kevin Walsh, Associate Professor and Reader, School of Earth Sciences, University of Melbourne (Infrastructure, Coastal Water Resources) Michelle Waycott, School of Tropical Biology, James Cook University, Townsville seagrasses: Allyson Williams, Emerging Technologies, Department of Primary Industries and Fisheries, Queensland (Fisheries and Aquaculture) Acknowledgements We wish to thank the many staff from the Department of Environment and Heritage (DEH) with whom we held useful discussions and who provided advice and information, and in particular, the staff from the Australian Greenhouse Office (AGO). Discussions held with staff of CSIRO, Geosciences Australia, etc, during the first national conference of the National Sea Change Taskforce, SEA CHANGE 2006: Meeting The Coastal Challenge Port Douglas, April 2006 and the adjacent AGO stakeholder workshop were also helpful. We would also like to thank David Blackburn, a coastal environment consultant, for helpful suggestions in the early planning stages of the project. Catherine Collier provided expert advice and assistance for the section on seagrasses. Anne Brewster gave helpful editorial advice. The review and suggestions to improve the report given by Professor Bruce Thom were greatly appreciated. Photographs used in this document are either supplied by contributing authors from their personal collections or with permission from their employing institution, or are public domain photographs. i

3 TABLE OF CONTENTS Part I: Executive and Technical Summaries Section 1 - Executive Summary Introduction and purpose Features of the coastal zone, coastal systems and their drivers Characterising vulnerability to climate change Key issues and recommendations Beaches and dune coasts Estuaries Australian coastal ecosystems of mangroves, seagrasses and saltmarsh Australian coral reefs and coral communities Coastal infrastructure and water resources Fisheries and aquaculture Selected other coastal activities General findings and common issues 12 Section 2 - Technical Summary Introduction Beaches and dune coasts Estuaries Mangroves Seagrasses Corals and coral reefs Coastal infrastructure and water resources Fisheries and aquaculture Selected other coastal activities Suggestion for assessment process for Phase 1 vulnerability assessment Key gaps to fill Summary table for types of data (data classes) relevant to coastal vulnerability assessments Technical Summary Conclusions.. 37 Part II: Analysis for Coastal Zone systems and components CHAPTER 1: Introduction, background, methodology Context Recent activity/work/summaries Definitions and constraints Characteristics of the Australian coast Methodology...41 ii

4 CHAPTER 2: Beaches and sandy coasts Introduction Methods for assessing impacts on beaches Brief review and identification of gaps Gaps Climate-related thresholds Data and research needs Feasible assessment options...49 CHAPTER 3: Estuaries Introduction Analysis of Climate Change on Estuaries Identification of gaps, including need for integrated assessment Implications for Estuaries Feasible assessment options...53 CHAPTER 4: Coastal ecosystems Mangroves and associated tidal wetlands Seagrasses and seagrass communities Corals and coral reefs Feasible assessment options coastal ecosystems...71 CHAPTER 5: Coastal water resources Introduction Methods for Assessing Impacts on Coastal Water Resources Implications for Coastal Water Resources Review of previous vulnerability studies Gaps and critical thresholds Feasible assessment options...76 CHAPTER 6: Coastal infrastructure Introduction Methods for assessing impacts on infrastructure Brief review of previous vulnerability assessments and identification of gaps Planning issues and vulnerability assessment Climate-related thresholds Data and research needs Feasible assessment options...86 CHAPTER 7: Aquaculture and fisheries Introduction Brief review of Fisheries and Aquaculture Assessing potential impacts of climate change on Fisheries and Aquaculture Feasible assessment options...93 iii

5 CHAPTER 8: Selected other coastal activities..error! Bookmark not defined. 8.1 Introduction Methods for assessing impacts and identification of gaps Climate-related thresholds Data and research needs Feasible assessment options Appendix A The nature and type of vulnerabilities that are possible for the coastal zone Appendix B List of acronyms Appendix C References iv

6 Part I: Executive and Technical Summaries Section 1. Executive Summary 1.1 Introduction and purpose This report forms part of the planning and preparation by the Australian Greenhouse Office (AGO) for an assessment of vulnerability to climate change of the Australian coastal zone, under the umbrella of the National Climate Change Adaptation Programme (NCCAP). The purpose of the report is to: 1. provide a concise summary of the extent of knowledge (including gaps) of: methods for assessing potential impacts of climate change on coastal systems; the data required to conduct such assessments; scientific understanding of the sensitivity of coastal systems to climate change, including climaterelated thresholds; and 2. identify and prioritise research needs that will lead to a feasible and practical vulnerability assessment within a reasonable timeframe. The report has two parts with Part I providing an Executive Summary and a Technical Summary and Part II providing the detailed analysis for the various coastal systems and components. 1.2 Features of the coastal zone, coastal systems and their drivers If we consider the coastal zone to include the coastline, nearshore reefs, nearshore islands, nearshore parts of the continental shelf, estuaries, tidal flats, coastal sand dunes and the coastal land margin, then features of the Australian coastal zone include: over 80% of Australia s population most of the top tourist destinations, world heritage sites and national heritage sites around 1000 estuaries of which more than a quarter are modified by human activity or habitation Seven capital cities Globally significant ecosystems including coral reefs, mangroves and seagrasses Many seachange shires and councils and 36 Natural Resource Management (NRM) regions The conduit to our export economy A significant percentage of Australia s water resources. The potential impacts of climate change on coastal systems are many (see box). In addition, Australians have been moving a significant portion of their assets to slightly more hazard prone areas within the coastal zone. Examples of the possible impacts and potential vulnerabilities for a typical Potential impacts of climate change on coastal systems Sea level rise and shoreline erosion Changes in wind and wave climate causing changes in local erosion rates Increased coastal flooding caused by higher mean sea levels Increased salt water intrusion into aquifers Changes to streamflow caused by changes in runoff rates Progressive inland migration of coastal ecosystems such as mangroves & saltmarshes Increased coral bleaching events due to rising water temperatures Changes to ocean chemistry affecting ability of corals and other marine calcifiers to produce their skeletons (for corals this would make reefs less robust to the forces of erosion) Increased frequency and/or intensity of tropical cyclones and associated storm surges Changes to ecosystems within or surrounding protected areas. inhabited coastal regime are 1

7 illustrated in Figure 1. The illustration is for a reasonably typical coastal regime in a tropical location with a seaside town located adjacent to a sizeable river and its associated estuarine-wetland system. Many of these impacts can also be caused by processes other than global-warming induced climate change, for example by seasonal to decadal climate processes or by human population pressures. Other possible contributors to coastal change are biophysical processes such as natural vegetation life cycles and normal physical interactions between the coast and the sea. Many changes to the coastal zone are natural in origin. A vulnerability assessment would need to keep this in mind, particularly when attributing cause of past observed changes. It should be designed to assess any increased vulnerability related to recently observed global warming and that anticipated in the reports of the Intergovernmental Panel on Climate Change (IPCC). Figure 1. Illustration of potential vulnerabilities to climate change impacts of a typical, tropical inhabited coastal regime i. This diagram also gives an indication of the dynamic nature of the coastal zone and the potential for multiple stresses. Note: Text rectangles describe the coastal systems illustrated, while text ovals indicate the potential climate change impacts. Seagrass impacts Altered wave/beach regime Wind/storm shifts Urban Ecosystem Urban water supply and water quality (algal blooms) Coral Reef/Pelagic Ecosystem Insect vectors(+ or -) Coral bleaching, shrinking Harbour changes Urban intrusion Urban flooding Mangrove habitat loss Saltwaterfreshwater interface T, ph changes Estuarine/Wetland Ecosystem Atmosphere Current and fisheries changes Ocean Land Coastal vegetation and parks ecosystems Growth and stress changes Runoffsediment balance 1.3 Characterising vulnerability to climate change Vulnerability A coastal community, ecosystem, economic unit or industry is vulnerable to climate change if it is susceptible to, or unable to cope with, the adverse effects of climate change impacts. The degree of vulnerability depends both on the magnitude of impact and on the amount, importance and value of the resources at risk. Three concepts are useful in characterising this vulnerability: Slowly accumulating impacts (e.g., the rainfall decline over recent decades in parts of southern Australia and the consequences for urban water supply); The capacity of a system or individual to cope; Thresholds associated with extreme events (e.g. corals bleach above a known temperature, damage to buildings occurs when storm winds exceed design standards, as occurred for many older buildings in Innisfail with Tropical Cyclone Larry in 2006, etc.). Thus, to assess overall vulnerability, it is important to consider impacts of both slow change and change in extreme events. 2

8 A full assessment of vulnerability requires consideration of the economic and social value of the goods and services, infrastructure or ecosystems at risk; combined with an assessment of resilience of the communities or ecosystems. The first requirement, however, is to identify and map the various components considered vulnerable and assess their respective risk of being impacted by climate change. Prior knowledge and expert assessment of the susceptibility of systems and the values at risk should enable selection for highest priority in assessment and thus a focused assessment process. Links between system complexity and the assessment process Many of the dynamics and ecosystem functioning of the coastal zone are complex, subject to biophysical, human pressure and climate variability and change drivers. Climate change impacts do not occur in isolation from the other drivers. Development of a national coastal zone vulnerability assessment also needs to be guided by the amount and quality of information available for the various coastal components, as well as by the current level of confidence and uncertainties in climate projections. This leads to consideration of a staged approach, with a first pass national vulnerability assessment over, for example, 12 to 24 months concentrating on identification, categorisation and mapping of coastal components and risks. A subsequent more comprehensive assessment may undertake more systems modelling and socio-economic assessment. This is Part I of a two part report. Part I provides an Executive Summary followed by a Technical Summary in which the concept of a staged approach to a vulnerability assessment is described, along with summary suggestions for feasible approaches. Further information, detailed analysis and relevant sources can be found in Part II: Analysis for Coastal Zone systems and components. 1.4 Key issues and recommendations A set of criteria may be useful to assist the design of a national vulnerability assessment, including differentiation of undertakings for first pass and second pass assessments. Criteria for setting priorities should include: results of the studies should be nationally or at least regionally relevant and important; availability of data (or identification of critical data that need to be refined or additionally collected); availability of feasible methodologies that do not require massive research and development; availability of expertise; prior knowledge of vulnerability of particular ecosystems (e.g. reefs to bleaching), and community relevance of and pressures for assessments (e.g. beaches in the Gulf of Carpentaria may not require first pass assessment at this time, but those of Gulf St Vincent would). These criteria have underpinned considerations in the preparation of this report. Nevertheless, the criteria and the further planning for the vulnerability assessment may benefit from further refinement in consultation with stakeholders. In the following pages, each system to be considered in a vulnerability assessment is presented in a standalone layout format with cross-referencing to the tables in the Technical Summary and to the relevant chapters in Part II. It should be noted that the recommendations in the following pages relate to the proposed first pass vulnerability assessment. Suggestions for a second pass (subsequent) vulnerability assessment are supplied in the Technical Summary. 3

9 1.4 Key issues and recommendations for coastal systems and components Beaches and dune coasts For additional information and analysis Technical Summary Cross-reference for beaches Tables 2a and 2b Part II Chapter 2 Half of the Australian coast is sandy comprising 10,685 individual beaches, many of which are important for tourism, recreation and residential development. Coastal population growth is placing further pressure on some beaches and dune coasts. Development approvals near beaches need to consider insurance risks and future liability for approving authorities. Vulnerability of beaches depends upon rates of sea-level rise, coastal erosion and frequency of extreme events. Sea-level rise is a major factor in beach profile re-adjustment but sediment supply and altered wave environments are also important. Increased tropical cyclone wind speeds, possible changes to east coast lows, more frequent storm surges and increased heavy rainfall events will all impact on beaches. Some beaches are mobile and relatively vulnerable to these forces, while others are less vulnerable to moderate climate change. The character and mechanics of beach change has been extensively studied in Australia in recent decades and good expertise exists. Nevertheless, assessment of vulnerability to climate change of beaches requires highresolution digital bathymetric and elevation data, which currently does not exist for much of the coastline. Key findings / research directions Estimates of vulnerable beaches can be made using geomorphological mapping and knowledge of standard sea-level response models; More expensive detailed vulnerability assessment requires modeling based on bathymetric and terrain elevation data, sediment supply and wave data; Greater vertical precision is required for digital data input to bathymetric and elevation models. Recommendations Historical aerial photographical data should be compiled to provide baseline data on shoreline change; Accurate surveys of coastal bathymetry and terrain elevation could be completed using laser altimetry but this is expensive and survey areas will need to be prioritised; A broad assessment is suggested at the national scale and more detailed assessment for high priority beaches (high value, known significant risk). 4

10 1.4.2 Estuaries For additional information and analysis Technical Summary Cross-reference for estuaries Tables 3a and 3b Part II Chapter 3 Australia s approximately 1000 estuaries are often highly productive coastal areas that provide shelter and breeding grounds for many commercially and recreationally important fish, crustacea and shellfish. Estuaries are also important for recreation and as a place for human settlement. Thus estuaries are important for coastal economies. A significant proportion of Australian estuaries are currently modified or severely modified by human activities. Incorporating understanding of climate change impacts into management for healthy estuaries will be of economic and ecological benefit to Australia. Estuaries will be particularly vulnerable to changes in river runoff which may affect the water balance and associated hydrological features of individual estuary types. Estuaries are also vulnerable to altered nutrient loads, warming sea temperatures, sea level rise and associated salt-water intrusion and storm surges. Any vulnerabilities that lead to degradation of estuary health may flow on to affect other ecosystems such as fisheries or coral reefs. Monitoring of biological, chemical and physical variables can enable detection of important changes in estuaries, but often multiple stresses have been operating over decades, so determining cause and effect is challenging. Determining vulnerability to future change in already stressed estuaries may require consideration of multiple stresses including those from climate change. Key findings / research directions Estuaries are complex systems and limited knowledge of the historical and current state of estuarine ecosystems will challenge our ability to identify and discriminate natural variations and climate-change induced impacts; Improvement in vertical resolution of digital elevation models is required, including detail of bathymetry within estuaries; Information contained in the National Land and Water Resources Audit Estuary Assessment 2002 (NLWRAEA) and the associated Ozestuaries website ( provides collated resources which can be augmented with data that may be available at a State or regional level to underpin a vulnerability assessment. Recommendations Supplement NLWRAEA and Ozestuaries information with local data and an image database to assist in priority setting for the assessment and also in the assessment of relative vulnerabilities; Use a range of existing physical process and ecological models to assess impacts of sea level, sea surface properties and temperature for key estuary types and key locations; For representative and key estuaries, develop a process to identify implications for human health (e.g. insect vectors), tourism, urban water supply, ports and harbours functioning, mangroves, seagrasses and discharge to oceans for potential impact on fisheries, coral reefs or other relevant ecosystems. 5

11 1.4.3 Australian coastal ecosystems of mangroves, seagrasses and saltmarsh For additional information and analysis Technical Summary Cross-reference for coastal ecosystems Part II Chapter 4 Tables 4a and 4b, 5a and 5b. Australia has some globally unique and important coastal ecosystems that could be stressed or experience dislocation under climate change. Mangroves, seagrasses and saltmarsh are very important habitats for functioning marine food chains and they support important industries. Mangroves and seagrass provide sediment binding and other stabilizing properties and mangroves are a small but significant carbon storage reservoir. Seagrasses are a habitat and food source for threatened species such as turtles and dugong. The vulnerability of these ecosystems varies around the coast and with species, and depends on rainfall and runoff changes as well as standard climate change variables, but productivity and range could be negatively affected. Key climatic variables for these coastal ecosystems are air and sea temperatures, sea level, rainfall and river flow (and associated discharge of nutrients and particulates), tropical cyclones and severe storms and ocean chemistry. Key findings / research directions Vulnerability of seagrasses, mangroves and saltmarsh to climate change is moderately understood, but these ecosystems provide habitats for many related organisms whose vulnerability is little known; A few regions have been well studied and monitoring programs exist, but large areas of the coast are poorly studied and do not have routine ongoing monitoring programs An assessment of vulnerability for the Great Barrier Reef (GBR) ecosystem and its constituent organisms is being prepared by the Great Barrier Reef Marine Park Authority (GBRMPA) and AGO to be published in Using this report as a benchmark, similar assessments are required for other key coastal ecosystems; Much of the relevant ecological information is available but is scattered and needs to be collated in one location; Further development of existing models or methods in order to assess combined impacts of sea-level rise and temperature change (and light availability for seagrasses) on the different seagrass, mangrove and saltmarsh communities would be very useful. Recommendations Broad-scale mapping of key variables (including distribution, relevant nearby ocean conditions, key climate parameters, nearby population, nearby land use, nearby ecosystems) in formats that can be easily overlaid would permit assessment of relative risks and indications of interactions between stressors; A one-stop web resource of relevant information including reports, publications, maps, and local, state and federal data should be developed, and could include recommendations for nationally consistent data management protocols and enable data and information exchange; Consideration should be given to including case studies, similar to the GBR assessment noted in the first column, for other critical locations. 6

12 1.4.4 Australian coral reefs and coral communities For additional information and analysis Technical Summary Cross-reference for coastal ecosystems Tables 6a and 6b. Part II Chapter 4 Australia has globally unique and important coral communities and coral reefs that could be stressed or reach critical loss thresholds under climate change. Government management of world heritage coastal ecosystems for the future needs to factor in climate change impacts. Corals, coral reefs and coral communities occupy a large part of our marine coastal zone and are immensely important to tourism and the local marine ecologies. They support several important industries including fisheries and tourism. There are very important sea-surface temperature thresholds for coral bleaching and associated moderate-to-long-term damage. A key climatic variable for corals and coral reefs is sea temperature, but rainfall and river flow, tropical cyclones and severe storms, ocean currents, waves and ocean chemistry are also important. Key findings / research directions Although vulnerability of corals to climate change is relatively well known, the reef environment provides habitat for many related organisms whose vulnerability is little known; An assessment of vulnerability for the Great Barrier Reef (GBR) ecosystem and its constituent organisms is being prepared by the Great Barrier Reef Marine Park Authority (GBRMPA) and AGO to be published in Using this report as a benchmark, similar assessments are required for other key reef areas, enabling classification of reefs by type and vulnerability; The broader ecological information relevant to reef functioning around Australia needs to be collated; Overlays of information to assess impacts on reefs from likely changes in the key climatic variables, identify possible refugia, etc would be very useful. Recommendations Broad-scale mapping of key variables (including distribution, ocean conditions, key climate parameters, nearby population, nearby land use, nearby ecosystems) in formats that can be easily overlaid would permit assessment of relative risks and indications of interactions between stressors; A one-stop web resource of relevant information including reports, publications, maps, and local, state and federal data should be developed; Consideration should be given to including case studies, similar to the GBR assessment noted in the first column, for other critical locations. 7

13 1.4.5 Coastal infrastructure and water resources For additional information and analysis Technical Summary Cross-reference for infrastructure and water resources Tables 7a and 7b Part II Chapter 5 and 6 Coastal infrastructure includes buildings, roads, powerlines, cables, pipes, maintained parklands, coastal defence works, ports and harbours. Coastal water resources include waterways, water supply systems, sewerage systems, drainage systems and natural water systems. The vulnerability of existing coastal infrastructure depends upon rates of coastal erosion and the frequency of extreme events, both of which are projected to increase in some locations. Changes that may occur to extreme events in a warmer world include increased tropical cyclone wind speeds, more frequent storm surges and increased heavy rainfall events. Sea level rise will alter the position of the coastline and needs to be assessed through the use of very accurate elevation data, which largely does not exist along the coastline at the required accuracy. The vulnerability of some infrastructure also depends on the design standards in place at the time of construction and the planning codes employed. Increasing population growth within the coastal zone will continue to place pressure on coastal water resources, while runoff is projected to decrease in many locations nationwide due to climate change. There have been several recent studies of the future of water resources in Australia s large coastal urban areas which provide important background for the proposed vulnerability assessment. Key findings / research directions Improvement in vertical resolution of digital elevation models is required, including coastal ocean depths; Climate change effects are often not incorporated in local planning schemes; It is unclear how well buildings are designed to resist strong wind events, which may become more frequent in some regions in the future; Recent water strategy documents have considered the need for adaptations to the effects of climate change on water resources (separately from the issue of population pressures). They indicated that for most urban locations, management and water conservation could minimise the need for further infrastructure over the next few decades, but additional infrastructure may be necessary beyond this timeframe. Exceptions may be southeast Queensland, the Perth region and possibly Sydney. It is not clear, though, whether consistent assumptions have been made among the various studies. Many rural coastal regions are likely to experience decreases in annual runoff, which may affect local water supplies. Recommendations Laser altimetry is a preferred method for determining coastal elevations and water depths accurately, although the cost is high; Review existing submarine infrastructure (such as pipelines) to determine whether design has adequately incorporated the possible effects of climate change; Survey relevant professional associations to determine the current vulnerability of stormwater systems; A national audit of local planning and management policies should be undertaken to determine how climate change effects have been incorporated; A catalogue of historical aerial photography should be compiled to determine the historical rate of shoreline change; An assessment of infrastructure vulnerability to changes in wind speed should be undertaken by comparing wind speed changes to the existing wind speed design standards; A survey of existing building stock within 100 km of the tropical coastline should be undertaken to determine its vulnerability under higher tropical cyclone wind speeds; Consistent national assessment of infrastructure requirements for water resources is needed. 8

14 1.4.6 Fisheries and aquaculture For additional information and analysis Technical Summary Cross-reference for fisheries and aquaculture Tables 8a and 8b Part II Chapter 7 The value of Australian fisheries production was about $2 billion in , and there has been a rapid growth in aquaculture production in recent years. Significant export income and local industry development require adequate planning for any climaterelated vulnerability. Fish harvesting occurs all around the Australian coastline, and fluctuations in fish stocks are known to be influenced by various factors that are climate-related. However, the impact on fish of changes in their habitat caused by climate change has only been established for a few species. Aquacultures include production of shellfish, crustacea, fish and pearls and while environments can sometimes be more controlled, diseases, water quality, water temperature and storm damage can still be sources of vulnerability. Since many of the responses to and sensitivity to the various climate change factors are highly species dependent, and since the degree of sensitivity is understood for only a few species, a vulnerability assessment of fisheries resources could be a large task. Key findings / research directions Few assessments have been made of the effect of climate change on Australian fisheries and aquaculture; A large number of species is utilised for commercial fisheries and sensitivity to climate parameters is species dependent; Sensitivity to climate parameters has been established for only a limited number of species; Aquaculture seeks to optimise environmental conditions for production, including site selection. Some knowledge is available on different optimal conditions for different species, but the various industry vulnerabilities have not been assessed. Recommendations More information is needed on the climate sensitivity of fisheries species; A vulnerability assessment would best be focused on those species with known climate sensitivity. 9

15 1.4.7 Selected other coastal activities For additional information and analysis Technical Summary Cross-reference for Selected other coastal activities Tables 9a and 9b Part II Chapter 8 The selected other coastal activities are protected areas, tourism and human health and safety. While there are significant governance and jurisdictional issues that may need to be addressed when considering capacity to adapt to climate change, they were beyond the scope of this report and may be considered for later vulnerability studies. Protected areas (wetlands, marine areas, national parks, national heritage and world heritage sites) within the Australian coastal zone and territorial waters provide tourism income, fisheries breeding grounds, ecosystem and economic goods and services, habitat protection and protection of historical or iconic locations. Human health and safety of individuals and communities in the coastal zone can be impacted by changes to temperature, humidity, storms, sea level, floods or droughts. The magnitude of health impacts will be influenced by local environmental conditions and social behaviors (resilience), and the range of possible adaptations by individuals or communities - these would need to be included for a comprehensive assessment. High value tourism operates in the coastal zone, including World Heritage sites such as the Great Barrier Reef and Kakadu National Park. Tourism risk relates to actual and perceived degradation of tourism sites and risks to infrastructure that supports tourism. The importance of Australia s coastal tourism industry needs factoring in to a national coastal vulnerability approach. The tourism industry depends heavily on some key iconic beaches and key protected areas (such as the Great Barrier Reef [GBR]) and in turn those protected areas support vast coastal natural resources. The vulnerabilities to climate change of coastal tourism, protected coastal parks and marine areas, human health and safety are mostly linked to vulnerabilities in infrastructure, beaches and natural systems and so an assessment will draw heavily on assessments for those systems. 10

16 Key findings / research directions Protected areas: The methods for assessing impacts are basically the same as for other non-protected geographic areas (beaches, coastal environments and coastal infrastructure); More detailed visitor information would be useful; Priorities are to digitise detailed maps, assess the need for flora and fauna corridors, and to improve the assessments of viability of ecosystems as a function of size; System-wide impact assessments may require a coordinated study over a longer term, including more extensive ongoing monitoring; Significant thresholds are mostly linked to sea level rise, possible large shifts in the salt-fresh water interface, or sea surface temperature (the latter being particularly crucial for corals). Human health and safety: Recent major studies on climate change and human health provide a national perspective, already contain useful national maps and can, therefore, form the basis for a vulnerability assessment; More detailed information may be needed on disease vectors (insects, etc.) in the coastal zone; For human health and safety, thresholds relate to events that overload the health/hospital system, events that exceed building design or coastline setback standards and hence put lives at risk, and introduction/generation of large new health risks (e.g. endemic malaria). Tourism: Critical thresholds for tourism relate to thresholds that significantly reduce tourism economic activity (loss of beaches or iconic destinations, reduction in coral reef size, perceived degradation of eco-values, health or safety concerns [e.g. about more severe tropical cyclones] by tourists); Recent studies of climate change and assessment of risk for tourism have been regional, local or feature-specific in focus. A national approach could assess the tourist-based industries, tourist sites and tourist-related infrastructure that have the highest economic value. Recommendations Protected areas: It may be possible to develop vulnerability assessments for flora and fauna of protected areas using existing biological-climate models; Broad estimates of potential partial loss of protected areas due to sea level rise could be obtained using GIS techniques, complemented by use of existing estuary models; In principle, social and environmental values could be identified for listed heritage places, and compilation of these could be undertaken with the aid of tools such as GIS and protected species data bases. Human health and safety: A useful first pass assessment of vulnerability to health risks within the coastal zone could be developed by combining data from recent climate change and health studies with expert assessments and mapping (the latter would need to cover potential infrastructure damage, flood risk, estuarine intrusion, potential distribution changes to disease vectors such as mosquitoes, etc); More research is needed to gain more specific information on thresholds that would stress the health system or lead to safety concerns. Tourism: Collect and refine tourism and tourismrelated infrastructure data; Use vulnerability assessments from other sectors (beaches, infrastructure, water resources, coastal ecosystems) to assess impacts on the high profile, high value tourist destinations. 11

17 1.4.8 General findings and common issues For additional information and analysis Technical Summary Cross-reference to: Tables 10, 11 and 12 This report (comprising Parts I and II) shows that sufficient data and high-quality expertise exist in Australia to undertake a preliminary first pass assessment in a relatively short timeframe. It is also clear that large data gaps exist for compilation of detailed vulnerability studies and therefore this report suggests a phased approach. For a first pass assessment, there is a need to compile nationally consistent, accurate and readily available data sets, as well as the relevant metadata and to improve the accuracy of coastal elevation data. For ecosystems, interactions between the components make vulnerability assessment complex and more research is needed on both natural change and that induced by climate change. More work is also needed to understand multiple stresses and their interactions. It is suggested that essential preparations for a more comprehensive vulnerability assessment include: Improvement in understanding of the impact of climate extremes and the thresholds of vulnerability of all systems under consideration; Improved/new valuations of ecosystems and their productivity; Improvement of a range of ecological models; Compilation of relevant socio-economic information; and Extension and expansion of the expertise developed for key ecosystems or in key centres (such as the studies of the Great Barrier Reef or within Cooperative Research Centres or Australian Research Council Centres of Excellence) to other ecosystems around the coast. It is worth considering how these may be commenced/upgraded in preparation for a second-pass vulnerability assessment. Many researchers have been working on new remote sensing applications to monitor coastal ecosystems and map features such as mangroves, seagrass, algal blooms, and water quality indicators. Satellite systems have improved over time and a major concern in using remote sensing technologies to detect change has been temporal stability of the output from observing instruments and processing algorithms. In future, as homogeneous timeseries and datasets become available, these technologies should be among the primary tools for coastal vulnerability assessments. It is suggested that, for a first pass vulnerability assessment, the key gaps to fill that are relevant across many of the systems or components are: Improved accuracy for shoreline position and near-shore elevation; Digital elevation matched to near-shore digital bathymetry (improve homogeneity between data sets); A collated set of visual records (primarily historical and recent aerial photography and satellite images) for beaches, dunes, estuaries, river outlets and past storm damage; Refinement of the current understanding of the drivers of coastal change particularly relevant to the Australian region, and in particular the impact of extreme events and episodes; 12

18 A survey of the national status of planning schemes and local ability to use climate change information in planning; A coordinated national coastal zone assessment of historical physical damage and damage costs from extreme events to underpin the same assessment of damage and costs from potential future changed regime of extremes; A common set of information for the coastal ecosystem (knowledge status, economic value, who looks after/has responsibility for coastal segments and ecosystem components and who conducts research). This should include consideration of development and expansion of the concept of a central OZCoasts Portal for information and data exchange and decision support. An agreed set of data management protocols for the many coastal datasets and progress to implementing these would contribute substantially to consistency in the outputs of the vulnerability assessment. Finally, a coordinated process would be needed for a vulnerability assessment that takes a staged approach and plans a first pass assessment within a 1-2 year time-frame. The Technical Summary suggests a feasible process to assess the main systems and components and then give some consideration to interactions between systems where relevant or significant. It is also suggested that a first pass assessment concentrate on production of a set of maps, data sets and expert assessments. 13

19 Section 2. Technical Summary 2.1 Introduction to Technical Summary This work forms part of the planning and preparation by the Australian Greenhouse Office (AGO) for an assessment of vulnerability to climate change of the Australian coastal zone. The report has two parts: Part I: Executive and Technical Summaries and Part II: Analysis for Coastal Zone systems and components with the latter providing the detailed analysis and relevant sources. The methodology employed in the project involved compilation of vulnerability matrices for each sector, in order to identify the main climate drivers. A brief review of previous work performed on vulnerability assessment in each sector helped identify available options for data sources, methods and models that could be used in a nationally focused vulnerability assessment. Gaps in previous research and data were also identified, as well as crucial climatic thresholds where known and/or understood. Recommendations are made regarding the form of an initial national assessment of vulnerability of the coastal zone to climate change. The technical summary section encapsulates the nature of each of the systems under consideration for inclusion in a national assessment of vulnerability. Table 1 lists the components examined and their chapter number in Part II of the report. In the following pages, each system is presented as a two page spread with the first page identifying key characteristics of the system, what is known about potential vulnerability, and some basic information on expertise and gaps. The second page indicates what a first pass vulnerability assessment might look like its contents and feasible options, along with an indication of what may be needed to complete a subsequent more comprehensive assessment (second pass). Each two page spread contains two tables, labeled Table 2a and 2b, and so on. This synthesis of the analyses for the systems is followed by a summary (Table 10) which shows how the assessment of the various components could be integrated. A coastal zone vulnerability assessment is a large task requiring consideration of many systems/components, some of which are interdependent. In order to provide practical and usable output in a reasonable timeframe, a phased approach is suggested. The Technical Summary tabulates basic requirements for two suggested phases, with the Second Pass suggestions being indicative only. While data and methodology gaps can be found for all systems and components, there are a few key gaps that are relevant to the overall success of a first pass vulnerability assessment. These are summarised in Table 11. Data are the foundation for a robust vulnerability assessment. A summary of relevant data classes and their status for vulnerability assessment work is provided in the last table of the technical summary (Table 12). Table 1. The components reviewed for this gap analysis Components Code For detailed description in Part II of the report: Beaches and Dune Coasts B Chapter 2 Estuaries E Chapter 3 Mangroves, Saltmarshes and associated Tidal M Chapter 4 Wetlands Seagrasses S Chapter 4 Corals and coral reefs C Chapter 4 Water resources W Chapter 5 Infrastructure I Chapter 6 Fisheries and aquaculture F Chapter 7 Protected areas P Chapter 8 Tourism T Chapter 8 Health and safety H Chapter 8 Note: all acronyms and abbreviations in the following tables are supplied in an Endnote at the end of Part I. All author references are supplied in Part II of the report. 14

20 Table 2a. BEACHES AND DUNE COASTS Current knowledge on vulnerability - summary Climate change driver (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Likely impact Sensitivity Known thresholds assessment and confidence Beach response to sea-level rise Extreme storms Increased waves and wind -Significant erosion of beach and backing dunes or land -Loss of beach and erosion buffer -Loss of beach width and beach amenity -Potential erosion of backing dunes or land and inundation -Loss of erosion buffer for storms H G M G H G M/L G M/L G -Frequency and intensity of storm events impacts on beach recovery times -Some beaches may erode beyond point of recovery -Wave energy flux calculations indicate sediment transport capacity KEY CHARACTERISTICS - Largest category of coastline - Some beaches mobile and vulnerable, others less vulnerable to moderate climate change SCALE - Half the coast is sandy - 10,685 individual beaches - 15 morphological types - Climatic influence on beach materials VALUES - Some beaches iconic value - Beaches high tourism value - Beaches high amenity value - Some beach dune systems of high habitat and conservation value Rising sea level Increased sea temperature Increased air temperature Reduced rainfall Enhanced rainfall -Intrusion of saline water into freshwater sandy aquifers -Loss of beach width and beach amenity -Elevated impact of waves and inundation -Impact on coral beaches with increased bleaching events -Alteration of interdidal biotic and chemical processes, -Altered vegetation coverage of sand coloniser plants -Reduction in coastal sediment supply -Altered vegetation coverage of sand coloniser plants. -Increase in coastal sediment supply -Altered vegetation coverage of sand coloniser plants. M G H G H H M G M G L/M L/M L/M M M G M G M G M G -Depends on local aquifer -Bruun rule provides ratio of sea-level rise to metres of erosion (applicability limited) 0.8 degree rise (approx) causes mass bleaching, 2-3 degree rise causes coral death - Threshold not known - Threshold not known, depends on local conditions - Threshold not known, depends on local conditions CATEGORISATION OF KNOWLEDGE *Excellent understanding of morphodynamics of different beach types * Good overall understanding of beach processes and sedimentation EXPERTISE AND DATA (WHO/WHAT/WHERE) * Good expertise available from coastal scientists (universities, GA ii, CSIRO) * Engineering data and historical photogrammetry most resides locally, not nationally connected 15

21 Table 2b. BEACHES AND DUNE COASTS: Summary of methodologies and technical requirements Synthesised from Chapter 2 of Part II (for references, refer to relevant chapter in Part II) Data collection Information on beaches Models and case studies to identify impacts Feasible approaches First Pass Assessment Second Pass Assessment National scale - Aerial photography - Satellite data - Wind/wave data - Tidal data (NTC iii ) - Demographic data - Improved data for DEM iv Regional/Local scale - Beach profile data - Wave energy flux/sediment transport data - Past change data National scale - Detailed national DBDEM vii - National GIS database for population, housing and infrastructure near coast Regional/Local scale - State-based data Information Systems: - Databases/metadata - Geomorphic mapping - Australian beach safety data base (Sydney University, Prof Short) - LOICZ v typology - Requires either existing coastal geomorphic mapping (with detail on fundamental vulnerability factors for coastal hazards) or availability of aerial photography to complete gaps National scale - Indicative assessment using basic Bruun-Rule principles Regional/Local scale (subset study) - Morphological behaviour model (Cowell et al 1995) - GIS vi -based model (Hennecke et al 2004) - Stochasitic simulation model (Cowell et al 2006) National scale - Second pass indicative assessment Regional/Local scale - Morphological behaviour model (Cowell et al 1995) - GIS-based model (Hennecke et al 2004) - Stochasitic simulation model (Cowell et al 2006) National scale - Geomorphic mapping - Sharples (2004) first pass indicative assessment approach Regional/Local scale - Only feasible to conduct more detailed modeling studies for high priority beaches (iconic or already vulnerable) - Socio-economic valuations of selected beaches National scale - Second pass assessment with incorporating selected detailed regional modelling Regional/Local scale - Extend detailed morphological/gis based modeling to key vulnerable beaches identified from first pass assessment - CoastClim and CVI viii model validation 16

22 Table 3a. ESTUARIES Current knowledge on vulnerability - summary (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Climate change driver Likely impact Sensitivity assessment and confidence Known thresholds Rising sea level Sea level rise salinity incursions - Increased inundation. - Increased erosion and sedimentation. - Changes in marine and estuarine vegetation diversity and coverage i.e. increase in mangroves and seagrasses, loss of reeds and rushes. - Change from estuarine endemic to marine fauna H G H G - Loss of estuarine vegetation species. - Landward migration of vegetation. - Linked to saltwaterfreshwater interface KEY CHARACTERISTICS - Interface between land catchments and coast. - Unique (endemic) biodiversity of flora & fauna. SCALE - Around 1000 estuaries. - Only 50% are considered in nearpristine condition. VALUES - Productive ecosystems sustaining coastal ecology and fisheries. - Important for recreation and as a place for settlement. Storm surge Hydrological change/flow Rainfall/runoff/ turbidity changes Shoreline erosion - Increased saltwater inundation. Increased erosion. - Altered nutrient and sediment budgets. Altered vegetation extent and coverage. Change from estuarine to marine fauna - Reduced environmental flow increased salinity. - Restriction in use and distribution of estuarine fish species. - Increased or reduced sedimentation depending on increase or decrease in rainfall. - Altered vegetation coverage. - Altered productivity and bio diversity - Increased sedimentation. - Reduced productivity. - Altered vegetation coverage. M/H M M/H G H G M/H M - Increased occurrence of water stratification. - Increased occurrence of high salinity levels. - Loss of estuarine vegetation species. - Increased occurrence of water stratification. Reduced flushing of stagnant salt wedge types - Loss of estuarine vegetation species. - Increased nutrient enrichment - high eutrophication levels. - Shallowing of estuary bathymetry. CATEGORISATION OF KNOWLEDGE * Moderate understanding of ecosystem function * Weak on estuarine water quality and processes * A few estuaries well studied, others not * Multiple stress (stresses on estuaries from a number of pressures) poorly understood EXPERTISE AND DATA (WHO/WHAT/WHERE) * Much data resides locally, not nationally connected * Limited systematic data Ozestuaries ix & NLWR x Estuaries Audit, * Good expertise available in universities, AIMS xi, State and Local Government agencies. GA Increased water and air temperatures - Productivity changes - Diversity changes - Increased potential for pest invasion. M W - Loss/change in distribution of estuarine vegetation. - Presence of marine pest species thresholds mostly unknown 17

23 Table 3b. ESTUARIES: Summary of methodologies and technical requirements Synthesised from Chapter 3 of Part II (for references, refer to relevant chapter in Part II) Data collection Information systems for estuaries Models and case studies to identify impacts Feasible approaches First Pass Assessment Second Pass Assessment National scale - Demographic data for major populated estuaries Regional/Local scale - Collect photogrammetric, photographic and satellite image resources Selection of Estuaries (SE) - Increase number of estuaries studied - Undertake more detailed regional assessments to identify risk priorities for policy action Information Systems: - Database of historical and current records and metadata (including types)for the SE - Map set for SE - Requires either existing coastal geomorphic mapping (with physical detail for the SE) or availability of aerial photographs to complete gaps Quality control and Comparison - Required to assist estuary selection - Same as above, but more focused on regional assessments for more specific risk assessment for vulnerability - Tidal and water quality models (consider SERM & SedNet xii ) - Waves/ swell/ beach run-up methodology - Runoff assessment methodology - Water temperature impact assessment methodology - Tropical cyclone and east coast low impact assessment method for relevant regions - Improvement of models for integrated assessment - Identify geomorphic units within estuaries, eg. estuary mouth, inflow rivers, etc, as indicator units to assess estuarine health and vulnerability to change from both human induced and climate change processes - Using output from models, etc, use an expert judgment process to provide flow-on implications for human health (e.g. insect vectors), tourism, urban water supply, mangroves, seagrasses and discharge to oceans for potential impact on fisheries or coral reefs, etc. National scale - Use estuary system models - Improve the integrated assessment Regional/Local scale - Extend GIS based modeling to key vulnerable estuaries identified from first pass assessment 18

24 Table 4a. MANGROVES, SALTMARSHES AND ASSOCIATED TIDAL WETLANDS Current knowledge on vulnerability - summary Climate change driver (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Likely impact Sensitivity Known thresholds assessment and confidence Extreme storms -Reduced vegetation cover L/M G - Can tolerate unless combined with other stressors. Little local data, but international data available Increased waves and wind -Changes in vegetation coverage M/H M - When combined with sea level rise KEY CHARACTERISTICS - High diversity of fauna, algae and microbial life - Stabilising properties SCALE - Occur in 2/3 of tidal-dominated estuaries and deltas - Mangroves 1m ha - Saltmarshes 1.3m ha VALUES - Critical for sustained productivity - Some protection against storm surges and tsunami - Sediment binding - Carbon storage - High value ecosystem goods and services - Crucial part of food chain Rising sea level Vegetation loss seaward -Migration landward Enhanced CO 2 Increased sea temperature Increased air temperature Humidity changes Reduced rainfall Enhanced rainfall -Increased productivity, but dependent on other limiting factors (salinity, humidity) H G - Unknown, dependent on sedimentation, groundwater inputs, tree vigour, tidal amplitude and other factors L G - Expect 30% enhancement in productivity, reduced by low humidity.and modified by salinity -Reduced productivity L/M G - Respiration doubles with every 10 C rise in temperature -Reduced productivity at low latitudes and increased productivity at high latitudes in winter - Species compositional changes -Productivity changes -Diversity changes -Forest losses, increase in salt flat cover -Mangrove invasion of salt marsh and freshwater wetlands -Reduced productivity and diversity -Increased diversity and productivity L/M G H M H G L G - Photosynthesis is reduced at leaf temperatures >35C, but leaf temperatures often lower than air temp. due to evap cooling and leaf orientation - Unknown, natural gradients could be used to obtain first assessment - Unknown, natural gradients could be used to obtain first assessment - Unknown, natural gradients could be used to obtain first assessment CATEGORISATION OF KNOWLEDGE * Moderate understanding of ecosystem function * A few sites well studied, others not * Combined impact of multiple stressors poorly understood EXPERTISE AND DATA (WHO/WHAT/WHERE) * Much data resides locally, not nationally connected * No systematic metadata, some bibliographies e.g. on Murdoch University website xiii * Good expertise available * Mostly in Universities and AIMS and linked to State DSEs xiv, some GA 19

25 Table 4b. MANGROVES, SALTMARSHES AND ASSOCIATED TIDAL WETLANDS: Summary of methodologies and technical requirements Synthesised from Chapter 4 of Part II (for references, refer to relevant chapter in Part II) Data collection Information on Models, methods and case studies to identify Feasible approaches First Pass Assessment Second Pass Assessment - Additional Surface elevation table (SET) monitoring instrumentation installations for priority locations - Sedimentation rates in mangroves, saltmarshes and other wetlands - Establish a network of SET - Additional ground water balance data in mangroves and tidal wetlands - Carbon and nutrient storage data mangroves Information Systems: - Fine-scale classification of the coast into typological units - Utilize and improve existing database, e.g. proportions of different wetland habitats in estuaries, tidal range etc. - Network into international SET data sets impacts - Methods are currently general purpose and need refinement and testing for different physical and environmental settings - Use a representative subset of mangrove environments (e.g. a matrix spanning variation in tidal range, sediment inputs/rainfall etc.) - Extrapolate Australia-wide from the representative matrix using existing metadata available from - Test whether available proxies of change are useful, e.g. can mangrove:saltmarsh ratio be used to predict rates of landward migration? - Improve data input for model testing and improvement - Improve understanding of carbon and nutrient cycling and trends, also impacts of severe storms and faunal responses to changes in habitat extent and availability - Use simple modeling approach based on Cahoon (2002, 2003), Nicholls (2004), etc. to assess impact of sea level rise. - Utilise data from SET installations (Australian and international) to verify model outputs - Improve models for use in different geomorphological settings - Methods to incorporate multiple stresses 20

26 Table 5a. SEAGRASSES KEY CHARACTERISTICS - High productivity - Complex structure - Habitat and food for other species -.Major losses in past 30 years SCALE - Extensive in all states - Coastal typically to 20m depth - Little explored inter-reefal areas and deeper waters VALUES - More than one WHA xv (Shark Bay, GBR) - Significant biodiversity - High value to fisheries, ecology, etc. - Basis of several key fisheries - Shoreline protection - Habitat and food for many other organisms -.Major habitat and food source for threatened turtles and dugong. Current knowledge on vulnerability - summary (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Climate change driver Likely impact Sensitivity assessment and confidence Known thresholds Extreme storms, tropical cyclones Increased waves and wind Rising sea level Enhanced CO 2 ACIDITY Increased sea temperature Increased air temperature Humidity changes Reduced rainfall Enhanced rainfall - Physical disturbance of seagrasses -Some ecosystems more sensitive than others - Coastal seagrasses, especially intertidal, disturbed due to physical disturbance - Loss of deeper habitats -Limitation in urbanized areas for recolonisation in shallow depths - Possible increases in seagrass productivity - Reduced survival due to excessive algal growth out competing seagrass - Increase frequency of seagrass burning and shallow intertidal die-off - Change in species distribution in subtropical/northern temperate regions - Burning of intertidal seagrasses M G H G M W H G H M M W H W H G M M H H - No net effect L G - Fewer low salinity incursions - Low salinity flood plumes cause local seagrass loss - Affect most coastal habitats L M H G - Observed losses with particular storm events and then recover. Some regions recovery short term, others > decadal. - Some species specific losses due to differing anchoring capacity of rhizomes. - No tolerance at current depth limits. - Benefit/neutral sandy coastal seagrass areas where colonization possible. - Full impact could be significant but limited knowledge of combined impacts. - Enhanced productivity but loss of intertidal seagrasses. - Competition with algae may increase. - Impact significant with 5 C increase. - Loss of intertidal seagrasses. - Loss of some estuarine communities due to lack of mixing; gain of communities lost with flooding - Combination of higher frequency and magnitude of low salinity events (20-25 ) would be a threshold threat CATEGORISATION OF KNOWLEDGE * Reasonable understanding of ecosystem function in some regions * A few regions well studied & monitored (e.g. SW Australia & GBR, Moreton Bay) * Large areas poorly studied and no monitoring * Interactions of multiple stressors poorly understood EXPERTISE AND DATA (WHO/WHAT/WHERE) * Good expertise available * Universities, e.g. UWA xvi, ECU xvii, JCU xviii, UTS xix, UQ xx, plus CSIRO, regional and state agencies * Data scattered and locally specific. 21

27 Table 5b. SEAGRASSES: Summary of methodologies and technical requirements Synthesised from Chapter 4 of Part II (for references, refer to relevant chapter in Part II) Data collection Information on seagrasses Models, methods and case studies to identify impacts First Pass Assessment Compilation of national seagrass distribution data - Compilation of species responses to different environmental conditions and disturbances - Compilation of historical seagrass habitat declines and recoveries Information Systems - GIS database of seagrass species distributions (with metadata) -Assess/map relative habitat availability; database of areas we predict seagrasses could grow - Database of disturbance responses of different seagrass communities - Database of seagrass losses and recovery with evidence for processes involved Quality control and comparison - Relative standards of data collection and resulting data quality would be useful - Priority to model impacts of sea surface temperature (SST) in shallow water seagrass ecosystems - Develop a model that assesses impact of sea level rise (SLR) and light reducing factors for seagrasses in different ecosystems - Use database of declines and recoveries and disturbance responses to verify model outputs Feasible approaches - Concentrate on near-shore seagrasses - Utilise current species distributional models to assess thermal tolerance ranges and predict changes in species ranges. (More detailed analysis of impacts on shallow subtidal and intertidal seagrass maybe required). - Sea level rise model could be developed based on physical characteristics of coastal habitats and relating to species growth rate dat Second Pass Assessment - Collect missing data on species environmental responses (disturbance responses, light and temperature in particular) - Improve data on deep water seagrasses - Improve/collect data on direct impacts of multiple stressors - Database by species of responses to different conditions - Enhance knowledge of this largely unstudied habitat (deep water seagrasses) - Direct evidence of multiple stresses needed (may be synergistic) and needs to be tested - Methods needed to build inferences from community to landscape scale - Improve and automate monitoring of key seagrass communities 22

28 Table 6a. CORAL COMMUNITIES AND CORAL REEFS Current knowledge on vulnerability summary Climate change driver Extreme storms, tropical cyclones (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Likely impact Sensitivity Known thresholds assessment and confidence - Physical destruction of corals Loss of habitat and food for other species H G - Natural stress from which reefs can recover, given time; usually localised Increased waves and wind - Physical destruction of corals Loss of habitat and food for other species M G - Natural stress from which reefs can recover, given time; usually localised KEY CHARACTERISTICS - High biodiversity and many unique species - Complex structure SCALE - 2 nd largest area of coral reefs in the world (19%) - ~50,000 km 2 - Coastal to shelf edge - Little explored inter-reefal areas (e.g. 90% of GBR) and some less studied, eg northern and Ningaloo reefs VALUES - Largest WHA (GBR) - High biodiversity - High value to socioeconomics, tourism, regional ecology - Shoreline protection - Habitat for many other organisms Reef bases fisheries (rec and comm) Rising sea level Enhanced CO 2 Increased sea temperature Increased air temperature Humidity changes Reduced rainfall Enhanced rainfall - Increase space available for some presently restricted coral communities - Loss of corals which become too deep - Reduce coral calcification - Reduce calcification of other marine calcifiers - Increase frequency of coral bleaching - Increase in area available for reef/coral growth - Associated reef organisms, e.g. sea birds, marine reptiles What about them?? M M M M H M H M H G M M H M - No effect L G - Fewer low salinity incursions; maintenance of winter-like conditions - Low salinity flood plumes cause local coral death - Affect reefs further offshore L G H G - Likely to benefit some reef flat communities - Full ramifications likely to be significant but limited knowledge - Reef-building corals only 1-2 o C below upper thermal threshold 18 o C minimum SST threshold but relatively small area increase - Documented reduction in bird populations associated with high air and SST events - Dependence of marine reptiles on ground temperature re sex of offspring - Documented death of corals with low salinity events CATEGORISATION OF KNOWLEDGE * Reasonable understanding of ecosystem function * A few regions well studied & monitored (e.g. GBR) * Large areas poorly studied and no monitoring * Interactions of multiple stressors poorly understood EXPERTISE AND DATA (WHO/WHAT/WHERE) * Good expertise available * AIMS, GBRMPA xxi, JCU (ARC xxii coral reef Centre of Excellence), UQ & other universities regional and state, e.g.wa and Murdoch 23

29 Table 6b. CORAL COMMUNITIES AND CORAL REEFS: Summary of methodologies and technical requirements Synthesised from Chapter 4 of Part II (for references, refer to relevant chapter in Part II) Data collection Information for corals Models and case studies to identify impacts Feasible approaches First Pass Assessment Second Pass Assessment National scale - Satellite mapping and monitoring - Collation of existing coral distribution, community structures etc into single national database Regional/Local scale - Northern and Western reefs need new/more data - Document past changes (e.g. JCU Centre of Excellence GBR History project; paleoclimatology). National scale - Detailed national DBDEM - National GIS database of coral reefs and communities Regional/Local scale - State-based data. Information Systems: - GBR data is good quality - Collate data from all reefs - Extract & expand Australian data from ReefBase ( - National-scale map of coral reef and community distributions. Quality control and Comparison - Use AIMS LTMP xxiii and ReefBase protocols - Survey programs for northern corals - National database of all location, bathymetry, species etc for coral reefs and communities. National scale - Research into geographic variation in vulnerability - Classification of reefs by type and vulnerability to different factors (e.g. terrestrial inputs, connectivity (larval supply), tropical cyclones Regional/Local scale - First pass integration of main stressors to assess combined impact - - overlay maps of coral distribution with other stressors/ threats (e.g. SSTs, rivers, tropical cyclones, population density, etc) - GBR and coral communities to south as case study. - Western Australian reefs influenced by Leeuwin Current as case study. Regional/Local scale - Mesoscale modelling of changes to ocean currents, upwelling etc in vicinity of coral reefs under climate change (e.g. Leeuwin Current, East Australian Current and its bifurcation point) - Regional projections of SST changes - Regional projections of river flow changes and extent of flood plumes. National scale - Use GBRMPA/AGO study and workshopping as a blueprint for identifying critical climate change factors for other reefs - Identification of possible refugia for corals and coral communities where are conditions suitable for expansion? Where are conditions likely to result in loss of ecosystems? Regional/Local scale - Use GBRMPA/AGO study to achieve a best yet vulnerability assessment for the GBR ranging from geomorphology to microbes and projected climate change impacts - Range of environments encompassed by GBR provides good models for many other corals around Australia. National scale - Incorporate oceanic chemistry, modeling of potential changes in Australian waters. - Whole bio-geo-chemical modeling of coral ecosystems Regional/Local scale - Initiate ocean chemistry monitoring (possibly through NCRIS marine plan xxiv ) - Expand case studies to northern Australian reefs. 24

30 Table 7a. COASTAL INFRASTRUCTURE Buildings, Roads, Maintained Parklands, Coastal Defence Works, Ports and Harbours, Water Resources Current knowledge on vulnerability - summary Climate change driver Extreme storms (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Likely impact Sensitivity Known thresholds assessment and confidence - Risk to viability of small communities, risk to offshore platforms M M - Building design codes set at a Category 4 cyclone Increased waves and wind - More frequent damage M G - When combined with sea level rise KEY CHARACTERISTICS - Support and amenity structures for local communities - Subject to design and planning codes and guidelines SCALE - National (e.g. coastal roads system) to local (e.g. houses, communities) VALUES - Health, safety and comfort - Contribute to community productivity - Conduit for goods and services including food and export economy Rising sea level Increased sea and air temperature, more heatwaves Decreased runoff Increased rainfall intensity -Inundation, road damage, seepage, coastal recession and related damage, overtopping of sea walls, risk to canal estates, risks to island communities - More possibility of invasive species being established - Planning and design issues for town planning and housing design M/H G M G - Freeboard assumed in planning - Disproportionate increase in number of hot days - Reduced environmental flows M M - Conservation or required investment in storage infrastructure -More frequent flooding M M - Stormwater drain capacity CATEGORISATION OF KNOWLEDGE * Only moderate knowledge of coastal physical processes * Good understanding of design standards EXPERTISE AND DATA (WHO/WHAT/WHERE) * All levels of government Federal, State, local * Central agencies such as ABS xxv, DOTARS and GA * Insurance and investment companies * Universities and private sector e.g. coastal geomorphologists, planners. * Engineers Australia (the National Committee on Coastal and Ocean Engineering) 25

31 Table 7b. COASTAL INFRASTRUCTURE Buildings, Roads, Maintained Parklands, Coastal Defence Works, Ports and Harbours, Water resources: Summary of methodologies and technical requirements Synthesised from Chapters 5 and 6 of Part II (for references, refer to relevant chapter in Part II) First Pass Assessment Second Pass Assessment Data collection National scale - Coastal aerial photography - Bathymetry, DEM - Coastal geomorphological type maps Maps of major intrastructure types e.g.. ports/harbours Regional/Local scale - Bathymetry, DEM National scale - More accurate national DBDEM - National GIS database for population, housing and infrastructure near coast - Compile national valuation of infrastructure data Regional/Local scale - Collect data on other infrastructure roads, bridges etc located in potentially vulnerably areas Information on infrastructure Information Systems: - Databases/metadata - Compile a data base of storm surge assessments done to date - Review of existing design standards for submarine infrastructure - Compilation of estimated changes in environmental flows Models, methods and case studies to identify impacts National scale - Analysis to create DEM of required vertical accuracy (about 2m) Regional/Local scale - Wind damage as per Walsh et al - Infrastructure flooding survey Stormwater Industry Association - Stormsurge use database to develop coherent national picture of vulnerability Regional/Local scale - NCCOE xxvi (2004) interaction matrix for local scale - Local studies using GIS coupled with socio-economic data to estimate vulnerability to climate change (especially sea level rise) Feasible approaches National scale - Identify likely regions of storm wind increases and storm surge inundation compare with design standards - National audit of local planning schemes Regional/Local scale - Survey of tropical coastal building stock National scale - Socio-economic valuations - Laser altimetry for accurate coastal elevation data 26

32 Table 8a. FISHERIES AND AQUACULTURE Current knowledge on vulnerability - summary Climate change driver Extreme storms Altered currents (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Likely impact Sensitivity assessment and Known thresholds confidence (varies between ocean, estuary or river fisheries and aquaculture, near-shore and ocean) - Impact on estuarine and river systems. - Aquaculture: infrastructure damage. - Distribution of fisheries - Change to prey distribution. - Changes to larva distribution and hence recruitment. M/H M For nearshore But for ocean: L G Depends on species - Can tolerate unless frequency increases significantly and combined with other stressors - Species dependent KEY CHARACTERISTICS - Existing pressures on some fisheries, commercial & recreational - Aquaculture a growth industry - Very few assessments of impact of climate change SCALE - Throughout Australia s national waters and in many gulfs, estuaries, and coastal rivers - Includes State and Commonwealth managed fisheries, some joint VALUES - Important food source - Important economically viable industry - Critical part of marine ecosystem Rising sea level and salinity incursions Increased sea temperature Reduced rainfall Enhanced rainfall Increased Air temperature - Impacts on estuary and river fish populations and on aquaculture - Could cause major shifts in populations. May have ecological and socio-economic implications - Changes to fish behaviour & reproduction, and catchability. - Altered nutrient supply in near-coastal areas. - Changes to timing of spawning. - Changes to availability of recruits - Freshening of some water areas - Aquaculture: change to water quality and quanity. - Aquaculture: change in geographic suitability for pond-based systems. - Change to fish condition and disease susceptibility. For estuary breeding grounds M W/M For ocean: L G H G H G For inshore H G H M - Species dependent - Species dependent - Species dependent - Species dependent - Species dependent CATEGORISATION OF KNOWLEDGE * Limited understanding of likely climate change impact * Very few species well studied, others not * Combined effect of multiple stressors poorly understood EXPERTISE AND DATA (WHO/WHAT/WHERE) * Catch data in State & federal fishery departments and CSIRO * Models & expertise in State DPIs xxvii and CSIRO * Commonwealth fisheries and aquaculture production data with BRS xxviii.and economic data with ABARE *Aquaculture disease, threshold data with research organisations (e.g. DPIs, CSIRO) Formatted: Bullets and Numbering 27

33 Table 8b. FISHERIES AND AQUACULTURE: Summary of methodologies and technical requirements Synthesised from Chapter 7 of Part II (for references, refer to relevant chapter in Part II) Data collection Information on fisheries Models, methods and case studies to identify impacts Feasible approaches First Pass Assessment National scale & Second Pass Assessment Regional/Local scale - Compile existing catch/effort data from state government fishery agencies &/or federal (AFMA xxix, ABARE xxx and annual BRS Fisheries Status Reports ) - Compile existing biological data from research organisations (limited long time-series data available) - Aquaculture: Compile existing production data from ABARE or state agencies. - Compile existing disease/nutrition data from research groups. - Continue data collection to extend species histories. Information Systems - Databases/metadata - Assess sensitivity to fishing levels: assessment reports available from DEH xxxi website. -Note: no national assessments have been done to date. National scale - Capture fisheries: not appropriate to assess on national scale due to variation among regionally specific species. - Aquaculture: site location issues: no model available, although temperature thresholds of key species are known. - Species thresholds, some studies (e.g. salinity & temperature thresholds of snapper) Regional/Local scale - Oceanographic models that have been linked with ocean ecosystem changes (e.g. western rock lobster: Caputi et al 2003, tuna: Young et al 1997, 2001) - Empirical models (e.g. barramundi: Robins et al 2004, King George Whiting: Jenkins 2005, Scallops: Caputi et al 1998) - Models derived in other regions for species also found in Australia (e.g. tuna in Eastern Pacific) - Develop, test and refine conceptual models. National scale Fisheries: - Assessment of suitable study species by length of data available and, e.g., by existing levels of vulnerability - Assessment of suitable models available. Aquaculture: -utilise known temperature thresholds of key aquaculture species to determine geographical viability of farms. Regional/Local scale Capture fisheries: 1. Run oceanographic models with climate change scenarios and assess impact of change. 2. Run climate-based correlative models with climate change scenarios. 3. Utilise models/studies done elsewhere and comparatively assess the impact. - Expand species selection for study where feasible. 28

34 Table 9a. SELECTED OTHER COASTAL ACTIVITIES TOURISM, PROTECTED AREAS, HEALTH AND SAFETY Current knowledge on vulnerability - summary Activity (Sensitivity = L/M/H low/medium/high Confidence = W/M/G weak/moderate/good) Climate change driver & Sensitivity assessment Known thresholds Likely impact and confidence Photo: Qld Government National parks and protected areas - Extreme storms & rising sea level loss of significant park area, crucial ecosystem components, loss of corridoors - Increased sea and air temperature ecosystem shifts M M M M H for some very sensitive marine parks such as GBR - Mostly poorly known - Temperature thresholds well known for corals, poorly known for other park ecosystems KEY CHARACTERISTICS - Coast a preferred living area - Large % of tourism is coastal - Large % of national parks and protected areas in coastal zone - Different health issues around the coast SCALE - Regional variation in these components VALUES - Significant % of national economy - Parks & protected areas provide heritage, ecosystem and tourism values - Healthy community Tourism Heath and safety - Rainfall changes ecosystem shifts - Extreme storms & rising sea level damage /loss tourism infrastructure and lost $$ from no access - Increased sea and air temperature changes in tourist destinations, heat stress, altered tourism seasonal patterns - Rainfall changes altered tourism patterns - Extreme storms & rising sea level - altered safety risks - Increased sea and air temperature heat stress, altered seasonal disease patterns - Rainfall changes including floods and droughts -- increased stress, altered geographical patterns of disease M M M M (highly variable between tourist destinations) M M (L/M for human activity but could be H for the ecosystems that are tourist attractions) M M M/H M (dependent on location) M L/M M L/M - Mostly poorly known - Mostly poorly known - Mostly poorly known - Mostly poorly known - Thresholds understood but application to particular regions difficult - Mostly poorly known - Mostly poorly known CATEGORISATION OF KNOWLEDGE * Recent assessment of general tourism risks at regional scale * Recent assessment of health consequences * A few parks well studied (e.g. GBR), others not * Possible combined impacts of human and climate change pressures not well understood EXPERTISE AND DATA (WHO/WHAT/ WHERE) * Data quantity and quality variable * Expertise: * DEH, DITR xxxii, GBRMPA, State DSEs, CRC xxxiii for Sustainable Tourism, Tourism Research Australia, ANU xxxiv, Dept. Health and Ageing 29

35 Table 9b. SELECTED OTHER COASTAL ACTIVITIES TOURISM, PROTECTED AREAS, HEALTH AND SAFETY: Summary of methodologies and technical requirements Synthesised from Chapter 8 of Part II (for references, refer to relevant chapter in Part II) Data collection Information Models, methods and case Feasible approaches First Pass Assessment Second Pass Assessment Parks and protected areas Heritage sites Tourism Health and safety Parks and protected areas Heritage sites Tourism Health and safety Sea level impact on size of National Parks and areas Vulnerable parts/fractions of heritage sites Better fine scale tourism data Collect sea level incursion and storm data for major inhabited areas Distribution data for vector spread, eg. mosquitos Data on site values economic, social and environmental Comparative data of vulnerability of Australian vs overseas tourist destinations Collect relevant data on resilience systems Consolidated database of all sites Generally improved data bases studies to identify impacts Assess a sub-set of sites, collect relevant output from rest of first pass vulnerability assessment (FPVA) Combine results from recent studies with GIS /mapping capability Methods to assess socioeconomic vulnerability and adaptability Data from rest of FPVA study plus expert assessment Map and assess outputs for locations of significant population densities Integrated assessment of these components 30

36 Table 10. Suggestion for assessment process for First Pass vulnerability assessment This table takes the information supplied in the system/component tables and, in schematic terms, suggests how the first pass assessment of the various components could be integrated. Code for third column: SLR= sea level rise, T= temperature, R=rainfall, SST= sea surface temperature Basic data and associated data tasks Shoreline position (R) DEM (R) DB (R) Aerial photography (C) Other visual records (C) Reefs (A and C) Selected demographic data (C) Selected Ports and harbours data (C) Fish catch (C) Basic maps of extent and location of mangroves, seagrass, reefs, estuaries, protected areas (C) Runoff and flood statistics (C) Turbidity reports (C) Selected infrastructure and local government data (C) Code: R= Refine C= Collate A= Additional Basic tasks Select geographic distribution of study regions for components, probably by expert assessment (EA). Sea level mapping for (a) broadscale and (b) selected beaches, estuaries, ports. Storm mapping. Downscale climate change data for selected estuaries, and major regions of M,S,C,F,I (some already exists, some needed) Itemise and compile coherent picture of observed change from Components and their primary assessment Beaches (B) SLR, storms Estuaries (E) SLR,T,R Mangroves (M) SLR,SST,R Seagrass (S) SLR,SST,R Corals (C) - link to GBRMPA work Infrastructure (I) SLR,T,R,storms Water Resources (W) SLR,T,R,storms Fisheries and aquaculture (F) SLR,SST,R,currents Protected areas (P) size, viability Tourism (T) viability of tourism assets and supporting infrastructure visual records. Health (H) SLR, T, R, storms These are central tasks needed for many of the studies for the individual components Assess direct impacts of climate change on these components Collation and integration EA to link E, M, S, C, F - related and interacting impacts Secondary impacts of B,E,I,W on M,S,C,F,P,T,H (where and/or if significant) Code: EA= expert assessment Linkages Mapping Outputs First-pass indications of linkages between systems and to socioeconomic vulnerability Possible survey re planning issues and vulnerability to climate change Mapping and specification of vulnerability levels (e.g. L/M/H) as well as confidence estimates: - by component - by community, where needed - by region/ coastal segment Map or tabulate thresholds where relevant or understood A collection (possibly central repository) of datasets and outputs Set of maps Set of expert assessments Set of description templates Possible survey or other results 31

37 Table 11. Key gaps to fill Gaps exist for all systems and components (to varying degrees of severity) and these are identified in Part II of this report. However, there are some key gaps that, if filled early, or at least a process commenced as soon as possible, would make a key difference to the ability to undertake useful vulnerability assessments. Some of these key gaps relate to refinement and/or new data, others to compilation and quality control of existing data. Key gap Reason Possible mechanism to significantly close gap Shoreline position and near-shore elevation. For most of the coastline, existing data are inadequate for really useful estimates of coastal incursion due to sea level rise. Where possible, extra detail is needed for estuary shape, mangrove regions, saltmarsh and coastal plains An aerial coastline lidar survey to obtain a linear transect of the coast. Digital elevation matched to nearshore digital bathymetry (ie. seamless dataset). A collated set of visual records (primarily historical and recent aerial photography and satellite images). National status of planning schemes and local ability to use climate change information in planning. A common set of information for the coastal ecosystem (the system, not just separate components) how economically valuable is it, knowledge status, who looks after it and researches it. and relevant offshore islands and cays. A refined coastal digital elevation model (DEM) would assist many aspects of a vulnerability assessment. A valuable resource for assessment of change that has already occurred, and for baseline for comparing future change. Coastal vulnerability is linked to local adaptive capacity and in particular ability to plan effectively. Research is often at local scale, as is coastal management; many agencies are involved. Coastal ecosystems are valued by Australians but our information base on values is sparse. Research and monitoring could be better integrated for the important task of identifying climate change risks. This requires removal of vegetation stands from satellite estimates of altitude, and a matching process between on-shore and offshore elevation estimates. (GA and ANU CRES xxxv are already working on the former). If data from a lidar survey were also available, a significant improvement in a national DEM could be achieved. An exercise to establish coastline segments to benefit most from collation of visual resources, to identify these resources (type, ownership, etc) and to create a relevant data set. A national audit of local planning schemes for use of climate change information, where there are consistencies and differences and what tools are available. Create a work plan to leverage key climate change information for the national coastal ecosystem, including its value and its key vulnerabilities. Create a directory of coastal management and research agencies relevant to each coastal region of Australia. There, are also longer term needs for additional research. For example, a coordinated assessment of potential thresholds for severe ecosystem stress as a function of rate and magnitude of change would be most useful for a more comprehensive vulnerability assessment. In addition, it has been suggested that a one-stop web resource for some of the systems to be studied, e.g. coastal ecosystems, would be very valuable. 32

38 Table 12. Summary table for types of data (data classes) relevant to coastal vulnerability assessments. Types/class of data Sub-class Typical scope (Current available data) DATA REQUIRED FOR ALL COMPONENTS Coastline delineation and coastal zone elevations Digital coastal elevation (DEM) Sea level (history and projections) Tropical cyclones and severe storms Visual images, e.g. photographs, satellite images, Google earth Near-shore bathymetry (oceans, estuaries, river outlets) Mean sea level heights Storm surge heights Tracks, strength, etc. National to approx. 9 second or better horizontal resolution; and approx +/- 10m vertical resolution Typical (temporal) length of record Not relevant (NR) Utility for climate change work (L/M/H) H Very useful if vertical resolution of ~ 0.2m can be achieved. National NR M (as presently available) National Mainly for selected populated areas (e.g. Cairns) Tropical and subtropical Photographs are from site to local to regional scale Satellite images national scale +/- 100 years approx. Historical data mostly < 50 years Projections need generating Some back 100 years, better record 40 years History M Projections H M/H M Issues Current resolution variations will lead to geographically variable accuracy of sea level intrusion maps Identify low-lying near coastal features that may be lost to sea level rise Choice of scenarios will give range of future sea level Detail available for Queensland coastal vulnerability needs to be extended to other regions (including collation of longer historical records) Temporal consistency; detail available for coastal Qld needed for other states Variable M Useful for identifying change Some historical images lost or languishing Likely requirements to bring to standard Lidar coastline survey to achieve ~ m vertical resolution New DEM data set in preparation by GA/ANU details available soon Completion/extension of GA/ANU work Include islands, cays and reefs Use Qld NRMW xxxvii (2004) study as prototype for other states Effort to identify & collate into single database Typical ownership (and/or repository locations) GA,ANU GA, ANU Navy BoM xxxvi, CSIRO, GA, Navy BoM, GA, CSIRO, Qld Government agencies, some universities BoM; Qld NRMW (2004) All levels of government 33

39 Climate characteristics e.g. tropical/ temperate and climatology of extremes Climate envelopes for different coastal regions National Up to 100 years H Data homogeneity Identify & collate into single database, high-quality climate records for coastal regions; return periods for current climate extremes & their regional variations around the coastline BoM, BIOCLIM/ OZCLIM xxxviii DATA REQUIRED FOR COMPONENTS: Sea properties Digital coastal and island elevation and near-shore bathymetry Geophysical data, e.g. beach types Sea surface temperature (SST) Wave observations and spectra (ie. wave climatology) Tides, ocean currents High resolution needed for reefs, islands, cays, saltpans and slow, flat estuaries Classifications of beaches/coasts, including morphodynamics. Local/regional tide and wave characteristics. Aerial photography of beaches Large-scale to subreef scale Tropical and subtropical Special local data may be needed for certain critical locations Generally beachspecific or by classifications Historical data available for all Australian waters. Includes satellite, in situ temperature loggers and automatic weather stations. Winds Gust return periods Variable and highly site-specific Observations often < 10 years; Projections needed M Limited high-resolution data; few projections of changes in vicinity of ecosystem components (e.g. ocean currents important for coral recruitment). NR H Vulnerability of MPAs xli, MPA design for the future, e.g. areas where corals, seagrass and mangroves could move or not. Loss of habitat for flora & fauna (e.g. seabirds). Aerial photography records can provide up to 60 years of change data. Length of record NR for classifications Up to 100 years; higher resolution past years. Some detailed projections available (e.g. ReefClim) xliii Variable mostly <40 years H H M Regional projections of sea level rise Needed for prediction of coral bleaching events; prediction of degree of susceptibility Needed for vulnerability of structures Good for GBR xxxix, some ports & harbours, but poor elsewhere For offshore regions: good for GBR but poor elsewhere Repair and consolidation of aerial photography records Useful high-resolution projections available for GBR but few if any available elsewhere. Linkage SST with ocean circulation and tides needed to develop ecosystem risk maps. CSIRO, EPA (Qld) xl, JCU, AIMS Navy GBR Depth & Elevation Model - GBRDEM xlii, CRC Reef; Navy; GA; JCU All levels of government, CSIRO, CRCs, some universities CSIRO, AIMS, DEH, GBRMPA, BoM and global SST data centres. BoM 34

40 Ocean chemistry Tropical cyclones (TCs) and severe storms Ecosystem communities maps, surveys, photographic records, remote sensing records Freshwater resources Extreme events ΡCO 2, DIC, ph and salinity. Also turbidity. Hit frequency, damage frequency Mangroves, seagrasses, estuaries/ wetlands, corals; e.g. locations & community structure of coral reefs and communities. Biodiversity maps or assays Water quality and temperature; outflows; natural and managed flows; Usage trends Heat waves, coral bleaching; floods, droughts; predator /pest episodes?? Data needed for all coastal waters with reefs and marine calcifying organisms Available on broadscale for all tropical regions. Improved analysis needed for local scale Mostly site or community specific Generally local, estuary or river basin scales Mostly localised data; heatwaves and droughts wider scale. Return periods -- heatwaves, floods and droughts. Almost no data available Some back 100 years, better record past 40 years. Projections needed (some available) ~ 10 years with some isolated early surveys River flows up to ~100 years Proxy river records several centuries for GBR Projections needed Patchy, episodic; reactive surveys to extreme events (e.g & 2002 GBR bleaching, cyclone Larry) H H M M H Need to monitor changes in ocean chemistry & impacts Key gap, no data currently available for Australian waters Source of localised disturbance for ecosystems, major infrastructure damage, health and safety issues. Primarily one-off surveys with continuous monitoring only for few areas (e.g. GBR); identify changes in community structure (e.g. corals after bleaching or TCs) Climate projections at sufficient resolution needed. River floods affect salinity, nutrients and turbidity and impact ecosystems and town water quality; e.g., need current and projected extent of freshwater flood plumes in vicinity of coral reefs. Lack of regular ecosystem monitoring for many areas; surveys usually reactive; little follow up of recovery after extreme events Co-ordinated national measurement & monitoring effort needs to be initiated similar to oceanic time series for Bermuda (BATS xliv ), and Hawaii (HOT xlv ) Useful projections for some locations, including GBR; use as model for other reef and ecosystem areas Improved database(s) Ongoing: Survey and monitoring needs integration into MPA xlvi design and management Quality assessment on historical data, additional modeling for projections. Good for GBR; additional research/compilation required for other reefs close to coast with high rainfall, and for town supplies Good for GBR; limited, reactive surveys for other coral systems and other ecosystems BoM; Qld NRMW (2004) GBRMPA; WA MPAs; state authorities, universities, OZestuaries, CRCs, etc. BoM; QLD NRMW (2004), state water authorities Universities, BoM, AFFA, GBRMPA; AIMS; JCU, UQ 35

41 Fisheries data Aquaculture data National parks and protected areas Tourist data Coastal land use e.g. natural, agriculture, population centres, infrastructure Population health and safety Commercial fisheries, Native fish, fish of tourism interest, production (catch), age, recruitment data Locations, numbers, productivity, disease, nutrition requirements National parks, RAMSAR xlvii wetlands, rare and endangered species habitats, MPAs, World and National Heritage Areas Seasonal and sitespecific visits Planning codes, land allocations and tenure, infrastructure standards, infrastructure valuations, proportions of infrastructure in lowlying areas, regions of multiple stress, e.g. coral reef stress from agricultural and other human use sources Sub-classes by climate impact, e.g., heat, moisture/insects, storms, etc. Mostly single species and localized, some State-scale. Species specific Generally sitespecific data Some state-based, some national tourism data Data generally local or state-based Recent national disease data is high quality Generally less than 40 years, some only 15 years Mostly of the order of a decade or two High in principle but mostly low adequacy High in principle but mostly low adequacy High spatial and seasonal variability of fisheries NR M Integration of climate change into MPA design Detailed mapping for adequacy (size, ability to cope with change, etc) NR M E.g., real and perceived loss of attraction of coral reefs to tourists (e.g. after reported bleaching events) NR M/H Variable data types, detail, length of records, etc. Need consistent assessments around coast. Understanding pristine vs non-pristine ecosytems, e.g. reefs close to population centres, agriculture etc vs reefs close to unmodified coastal landscapes. Variable M/H Disease risks vs population status (age, health/wealth). Recent studies investigating possible climate change impacts. For long-term, improvement of ongoing monitoring Mostly, collation and standardisation of information needed. More detailed data compiled for GBR and some MPAs, some additional data needed for others Good for GBR & some WA MPAs Identify infrastructure that supports tourism. National collation of existing data and knowledge, would be useful More detailed mapping DATA PORTALS AND ON-LINE DATA DIRECTORIES There are several, and the following are provided as indicative of the scope: State or Federal Governments State or Federal Governments GBRMPA, state and commonwealth agencies GBRMPA; state and commonwealth agencies, CRC for tourism Local, State and Federal governments, GBRMPA; state and commonwealth agencies ANU, State and Federal agencies 36

42 NEPTUNE (National Oceans Office): CSIRO Marine Data Centre: ERIN: Australian Natural Resources Data Library: Technical Summary Conclusions This technical summary has presented in tabular form consolidated information about coastal systems and their components and the types of information needed to undertake a vulnerability assessment to climate change. When read in conjunction with the corresponding chapters in Part II of the report, it should assist in the planning for a vulnerability assessment, including what is feasible in a given timeframe and what are the key gaps to be filled to ensure a widely useful assessment. 37

43 Part II: Analysis for Coastal Zone systems and components CHAPTER 1: Introduction, background, methodology 1.1 Context This report forms part of the planning and preparation by the Australian Greenhouse Office (AGO) for an assessment of vulnerability to climate change of the Australian coastal zone. It is part of the National Climate Change Adaptation Programme (NCCAP). The purpose of the report is to: 1. provide a concise summary of the extent of knowledge (including gaps) of: methods for assessing potential impacts of climate change on coastal systems; the data required to conduct such assessments; scientific understanding of the sensitivity of coastal systems to climate change, including climate-related thresholds; and 2. identify and prioritise research needs that will lead to a feasible and practical vulnerability assessment within a reasonable timeframe. This is Part II of the report. It contains the detailed chapters describing the findings for each coastal system, and where relevant, components of the system, e.g. coastal ecosystems and the main components of corals, mangroves and seagrasses. Part I of the report contains the Executive Summary and a Technical Summary consisting mostly of informative tables. The Executive and Technical Summaries also identify where there may be common data and research and development needs across the systems or components, as well as offering some suggestions on system linkages for a vulnerability assessment. 1.2 Recent activity/work/summaries Recent activity relevant to preparation for a national vulnerability assessment include Walsh et al 2004, two reports to the AGO (Kay et al 2005), a fishery report for the AGO by CSIRO (Hobday and Matear, 2006), vulnerability studies for the GBR underway at GRBMPA, and two workshops conducted in late 2005 and early 2006 (one technical to identify expert views on requirements and one for stakeholders to share information on stakeholder needs for information) These reports have identified a foundation to underpin a national vulnerability assessment. In particular, the Kay et al (2005) papers began the process of mapping out a national approach for a coastal vulnerability assessment and identified a wide range of existing resources. The current work, assessment of relevant international studies and gap analysis will assist in the process of establishing feasible options for a national approach. All of this, including the recent process, is summarized in Table 1. Table 1 Recent activity in preparation for a national first pass assessment of vulnerability of the coastal zone to climate change Timeframe Task/Item References/ process Output 2005 Summarise previous relevant work and discuss approach to a national assessment Kay et al (2005) 2 papers Review of past work and suggestions for a broad conceptual framework Dec 2005 Technical workshop National technical experts List of suggestions for research needs Early 2006 Stakeholder meeting Engagement of stakeholders Stakeholder needs 1. assessment of relevant Feasible options for a firstpass First half 2006 international studies Two reports to AGO vulnerability 2. gap analysis assessment 38

44 Table 1 focuses on the national scale. It should be noted that recently there has been considerable study and regional projects undertaken within State Government or Local Government jurisdictions, many of which will provide valuable data for a national assessment as well as potentially useful methodologies. This report is not meant to be an exhaustive review of all recent or current activity at all scales. Rather, it is intended to focus on feasible options for a national-scale assessment and identify significant inhibiting gaps. The primary level references/basic information set for this report include: The global scale projections of the Intergovernmental Panel on Climate Change (IPCC, 2001) and the earlier report on a methodology for assessing vulnerability to sea level rise (IPCC CZMS, 1992) The national and regional climate projections for Australia by the CSIRO Marine and Atmospheric Research (CMAR). Available from URL: The United Nations (UN) Millennium Assessment (MA) reports where they relate to coastal zones and in particular coastal zone ecosystems, e.g. the fifth synthesis report by the Millennium Ecosystem Assessment (MA, 2005), Ecosystems & Human Well-being: Wetlands & Water Synthesis. Available from URL: The report for the AGO Climate Change Risk and Vulnerability: Promoting an efficient adaptation response in Australia Available from URL: The reports from the AGO technical workshop and the stakeholder meeting (AGO, in preparation). 1.3 Definitions and constraints The IPCC has defined vulnerability as the degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change (IPCC 2001). It is a function of exposure, sensitivity and adaptive capacity, as illustrated in Figure 1 and for a full vulnerability assessment, the values of items, systems, infrastructure, etc., need to be assessed (Allen Consulting Group, AGO report, 2005). A common usage for the term vulnerability is for the impact on a system expected from an exposure to climate change (e.g. if sea level rises, the coast will be impacted, hence is vulnerable to erosion, etc.). Thus common usage often concentrates on the left-hand side of this diagram. A summary of the nature and type of vulnerabilities that are possible for the coastal zone is provided in Appendix A. In considering a national coastal zone vulnerability assessment, the work done and how it is structured needs to be guided by the amount and quality of information available for those various components. In addition, a vulnerability assessment is constrained by the inherent uncertainties in climate projections as they apply at various geographic scales (see Table 2). Confidence in the projections and the degree of certainty typically increase as the scale increases. This has been recognised in prior reports and studies and leads to consideration of a staged approach to a national vulnerability assessment, with a first pass assessment over, say, 12 to 24 months concentrating on the left-hand side of Figure 1, and a more comprehensive assessment subsequently (to incorporate the components on the right-hand side of Figure 1 and the bottom row of Table 2). 39

45 Vulnerability and its components Exposure Sensitivity Impact Adaptive capacity Values of impacted systems Vulnerability Adapted from the report to the AGO by the Allen Consulting Group (2005), in turn adapted from the Potsdam Institute for Climate Impact Research. Figure 1 Illustration of the steps/components of a full assessment of vulnerability, adapted from the report to the AGO by the Allen Consulting Group. Table 2 Degree of uncertainty matrix for climate change projections and related impacts. Higher confidence is indicated by darker shading Projections of Climate Drivers Estimation of Impacts Vulnerability assessment Global/national scale climate projections Broad impacts Broad-scale vulnerability Downscaled climate projections (to a regional level), e.g. southeastern coastline, wet tropics Regional impacts Sector or system specific impacts (e.g. regional tourism) Regional and sector based vulnerability, e.g. coral reefs in general, broad assessment for tropical mangroves, etc. Local projections (regional downscaling combined with mesoscale climate modeling and coastal ocean modeling) Local impacts (e.g. coastal wave/swell runup for a beach or estuary, or expanded range of a tropical species) General utility of data and methodology Local vulnerability e.g. for port or harbour, estuary, reef, mangrove region, etc. Confidence in projections 1.4 Characteristics of the Australian coast If we consider the coastal zone to include the coastline, nearshore reefs, nearshore islands, nearshore parts of the continental shelf, estuaries, tidal flats, coastal sand dunes and the coastal land margin, then features of the Australian coastal zone include: over 80% of Australia s population most of the top tourist destinations, world heritage sites and national heritage sites around 1000 estuaries of which more than a quarter are modified by human activity or habitation Seven capital cities Globally significant ecosystems including coral reefs, mangroves and seagrasses Many seachange shires and councils and 36 Natural Resource Management (NRM) regions The conduit to our export economy A significant percentage of Australia s water resources. Drivers for the coastal zone arising from climate change (associated with long-term global warming) are summarised in Figure 2. The main components of climate change that will impact on the coastal zone are identified. The most likely impacts from each component are differentiated between those that would cause ongoing effects on the coastal zone (given the label chronic) and those impacts that are episodic 40

46 but severe or those close to significant change thresholds (given the label acute). While a long period of ongoing impact can lead to a component reaching a critical threshold for significant change, the severe episodic impacts may cause a significant change threshold to be reached more rapidly, thus Figure 2 is useful for thinking about the nature of thresholds. Figure 2 Impacts of the main components of climate change on earth and biological systems at/within the coastal zone1. Potential impacts on earth and biological systems by the main components of climate change Components of climate change Surface Air Temperature Sea-Surface Temperature Sea-Level Rise Rainfall Wind CO 2 Impact Acute Chronic Habitat loss Vectorborne illness Heat-related illness Habitat loss Algal blooms Coral bleaching Wetlands Erosion Inundation Salt intrusions Flooding of vulnerable areas Runoff Sediment transport Vectorborne illness Water quality Flooding Drought Upwelling Waves/ swell/ slow sand, beach processes Wind Damage Storm-surge Calcification Plant fertilisation Ocean ph Marine ecosystem function The driving forces in Figure 2 do not operate independently of one another and can thus result in multiple stresses on a system and non-linear effects. The complexity in the behaviour of coastal systems in response to driving forces can be summarised as follows: For any given coastal systems, change is driven by: Climate forces which can be the result of either (1) natural climatic variability at different time scales; or (2) as a result of global warming ( climate change as used in this report); or Non-climate forces which are either (3) the result of natural biophysical processes (eg vegetation succession, internal geomorphic dynamics such as delta shifting or sediment accretion), or (4) human induced from activities such as catchment land clearing, seawall construction or sand mining. The climate change drivers may therefore have an independent impact on any given coastal system (e.g. coral bleaching). Alternatively, climate change may reinforce or mitigate the impact of the other 3 drivers at a given site and within a given coastal system (e.g. sea-level rise [driver (2)] adding to La Nina storm events [driver (1)] where beaches are starved of sand due to up-drift training walls [driver (4)]). An assessment of vulnerability to climate change would need to assess the additional vulnerability resulting from the additional driving factor of the global warming-linked climate change. 1.5 Methodology The methodology employed in the project involved the compilation of vulnerability matrices for each sector, in order to identify the main climate drivers. A brief review of previous work on vulnerability assessment performed in each sector helped identify available options for data sources, methods and 41

47 models that could be used in a nationally focused vulnerability assessment. Gaps in previous research and data were also identified, as well as crucial climatic thresholds where known and/or understood. Finally, recommendations are made regarding the form of an initial national assessment of vulnerability of the coastal zone to climate change. The Australian coast clearly has a national scale, but the components for a vulnerability assessment may have national scale, regional scale (eg the whole Great Barrier Reef) or local scale (eg Bondi beach or a local tourism operation on the Tasmanian coast).for practical purposes, suggestions made in this report are mainly confined to national or regional scale. It is important to recognise that there are many forces at work on the Australian coastal zone, its ecosystems and populations, besides potential impacts of climate change. For example, the impacts of natural (seasonal to decadal) climate variability on past coastal and ecosystem changes need to be disentangled as far as possible from climate change due to human influence, in order for observational evidence to be used either to support predictions or to help verify system models. This needs to be kept in mind when compiling the data needed for a vulnerability assessment and the methods to be employed. 42

48 CHAPTER 2: Beaches and sandy coasts 2.1 Introduction Fifty four percent of the Australian coast has been classified as sandy (see Table 3) and half of the coast is made up of beaches. According to Short (2006), the Australian coast has a total of 10,685 individual beach systems, which he has sub-divided into 15 beach types (6 wave-dominated, 3 tide-modified, 4 tide-dominated and 2 reef and rock influenced). These beaches receive the greatest impact from recreational and residential use resulting in high infrastructure investment and high population concentration near the beaches. Consequently, issues of coastal vulnerability related to climate change are important considerations for beach management. State coastal management agencies were established primarily to address concerns over beach erosion. Table 3 CSIRO survey of the Australian coast (Galloway et al, 1984) STATE Sand % Rock % Mud % Aeolianite % NSW NT QLD SA TAS VIC WA Totals Notes: The above represents the materials at the waters edge, (estimated per 10 km section on aerial photos.) Sand: sand beach, backed by dune or aeolianite; mangroves: in front of mangroves is sand; behind mangroves - mud. Rock: hardrock shores, except where shore platform has a beach at the back (sand); fringing coral reefs are rock. Mud: mainly Northern Australia and associated with mangroves. Aeolianite: found along great stretches of coast, but usually fronted by a beach (thus sand) Water: where defined coastal boundary cuts across straits and inlets. Other: alluvium; artificial coasts. The character and mechanics of beach change has been intensively studied in Australia over the last 3 decades. Form and process are closely inter-linked in beach studies and this work has often been termed the morphodynamics of beaches. Many available texts and review articles summarise the great volume of work in this area such as Viles and Spencer (1995), Carter (1988), Carter and Woodroffe (1994), Psuty (1993), Wright & Short (1984), Komar (1976 and 1983). Perhaps the most authoritative work on Australian beaches comes from Short (2006) who has studied the morphodynamics of beaches and has produced a series of books covering every beach in Australia (Short 1993, 1996, 2000, 2001, 2005, in press). Australian beaches are mostly made up of sand-sized fragments of carbonate or quartz. Heavy minerals are also found within beaches, but make up less than 1% of the coastal sands (Harvey and Caton, 2003). There are some gravel and shelly beaches but these are less common. A national review of beach materials by Bird (1978) illustrated the contrast between calcareous materials of the South and West, quartzose sands on the East coast and a variety of fine sediments on the Northern Territory coast. As described by Harvey and Caton (2003) the cause of this contrast in Australian beach sediments is largely climatic. In the south and west of Australia long-term aridity has significantly reduced any fluvial transport of weathered rock fragments to the shore. Between Broome and Bass Strait the only major river outlet is the Murray providing little sediment to the coast but instead causing infilling of its terminal lakes, Albert and Alexandrina. Many minor streams currently reaching the coast tend to deposit their sediment load within their estuaries. The beach sediments of Australia s arid coast are predominantly shelf-derived biogenic carbonate material: fragmented shell and skeletal material which has been deposited by marine transgressions during the Pleistocene period (Harvey and Caton, 2003). 43

49 On southern and western coasts large carbonate dune accumulations occur on the more exposed, high energy, shores, where large swells have transported the carbonate detritus to the beach from where it has subsequently been re-distributed by littoral drift and wind. Many large carbonate-rich dunes, accumulated during the Pleistocene, have become lithified to aeolianite (dunerock or calcarenite) through ground water movement, solution and redeposition and calcrete formation (Harvey and Caton, 2003). Quartzose sands of the south-east and east of the continent are, in contrast, of terrestrial origin. Harvey and Caton (2003) use three case studies of beaches in Australia to illustrate the variety of beach systems through the description of the supply and loss of beach materials, the variation of wave energy levels, tidal range and patterns of beach change. These case studies are; 1) Byron Bay, on the north coast of NSW, which is a high energy, micro-tidal beach with strong northerly littoral drift; 2) Adelaide, within the shelter of the Gulf St Vincent, which is a medium to low energy micro-tidal beach with significant littoral drift; and 3) Cable Beach near Broome which is a low energy macro-tidal beach with little littoral drift (see Harvey and Caton, 2003 pp 62-73). Beaches tend to assume a greater importance than other types of coast because of the Australian lifestyle and recreational beach use. This has led to some beaches having iconic status such as Bondi in New South Wales or the Gold Coast in Queensland. However, the vulnerability of such beaches differs. For example Bondi beach maintains an equilibrium state within its embayment and has a reasonable buffer and backing protection. In contrast, the Gold Coast beach is subject to significant longshore drift (around 500,000 m 3 per year), and requires artificial beach replenishment. In addition, there is a limited buffer and considerable tourism and development pressure. Different issues occur for tropical beach such as in Townsville, Queensland where artificial replenishment and hard rock protection has been used largely in response to cyclone and storm damage. Each of these three beaches are important from a human use perspective but have different vulnerabilities related to climate change factors such as sea-level rise and changes in cyclone intensity. 2.2 Methods for assessing impacts on beaches Methods for assessing the impact of sea-level rise on sandy coasts are usually discussed in terms of the simple two-dimensional Bruun Rule (Bruun, 1962) which asserts that sandy coasts will adjust and maintain their equilibrium in response to sea-level rise (see Figure 3). Subsequently, Dean and Maurmeyer (1983) modified this to produce a Generalised Bruun Rule applying to mainland and barrier beaches. Leatherman et al. (2000) computed shoreline change rates along the US east coast, producing a good correlation between sea-level rise and long-term erosion on eroding beaches. The results gave ratios of shoreline recession to sea-level rise ranging from 110 to 181, compared with the ratios of 50 to 200 according to Bruun's calculations. Leatherman (2001) asserted that this confirms that the lateral beach erosion rate is always two orders of magnitude greater than the rate of sea-level rise. The Bruun Rule has been criticized because its assumptions rarely apply in the real world and some authors have suggested abandoning the Bruun Rule (Cooper and Pilkey, 2004). While the Bruun rule may apply to locations with sufficient sediment supply, uninhibited equilibrium profile development and minimal longshore drift, all these conditions are rarely achieved. For this reason coastal scientists, including a number of Australians, have attempted to modify the Bruun model. Cowell and Thom (1994) produced a model for shoreline response allowing for sea-level rise and variation in sediment availability within sandy barrier-dune complexes. Cowell et al (1995) used a morphological behaviour model to simulate large-scale coastal change. Hennecke et al (2004) used GIS techniques to combine real-world examples with models and illustrate the projected costs of sea-level rise combined with storm damage along the Collaroy/Narabeen beach (NSW). A detailed study of coastal vulnerability for the Tasmanian coast (Sharples, 2004) recognised the limitations of the Bruun model but used its basic assumptions to identify which sections of the coast were susceptible to Bruun-style erosion resulting from sea-level rise. This approach was referred to by Sharples (2004) as a first pass mapping approach to assessing vulnerability. 44

50 Bruun Rule of coastal response to sea-level rise recession Dune height cut sea-level rise closure depth Source: Bruun (1962) fill Figure 3 The Bruun Rule Model An important factor in modelling is to identify the error limits and uncertainties of the predictions. Cowell et al (2006) stress the importance of admitting uncertainty in the modelling. They use stochastic simulation to manage predictive uncertainty relating to climate-change impacts on beaches. They also illustrate the different responses from different types of sandy coast to the impacts of sea-level rise (see Figure 4). Thus most methods for assessing impacts on beaches and sandy coasts are underpinned by the basic premises of the Bruun rule but the methods are increasingly becoming more sophisticated to include responses from different types of coasts, and different regimes of sediment supply, longshore drift and variations in wave energy and approach. It is clear that a basic approach such as that used by Sharples (2004) for Tasmania has merit in obtaining a rapid assessment over a large area. The detailed modelling by Cowell and others has the advantage of producing more reliable predictions at the local scale where the additional time and cost of such modelling may be warranted for vulnerable areas in terms of population or infrastructure at risk. The type of impacts will vary on different types of beaches as shown in Table 4. For example open coast beaches backed by sand dunes have a natural buffer for responding to sea-level rise and increased erosion. This is not the case for artificially protected metropolitan beaches such as Adelaide where the beach width is maintained by sand replenishment and backed by hard rock protection. In addition to local beach impacts over short-time frames, there have also been studies investigating longer term impact on beaches and regional sections of the coast. For example at Moruya Beach on the NSW coast over 30 years of beach monitoring data have enabled the identification of criteria, including climate conditions, necessary for foredune development at that site (McLean and Shen 2006). Similarly, over 30 years of beach monitoring data for the Collaroy/Narabeen beach (NSW) enabled Ranasinghe et al. (2004) to draw linkages between historic beach erosion and the climate patterns of the El Niño-Southern Oscillation (ENSO). Similar linkages and longer-term impacts on beaches from the Inter-decadal Pacific Oscillation (IPO) 1 and ENSO-related events have been demonstrated in changes to coastal geomorphology for the northern NSW coast (Goodwin 2005:Goodwin et al. 2006). Thus, while these studies clearly demonstrate strong climate controls on some beaches and some beach dynamics, an assessment for vulnerability to global warming-linked climate change will have to consider the extent of interaction between these influences. These studies are potentially useful, however, since they 1 IPO and ENSO are both climate variability phenomena linked to atmosphere-ocean interactions. 45

51 will help in understanding the impact of any changes to the frequency and/or intensity of such phenomena that may arise from global warming. Figure 4 Response to sea level rise on different beach types illustrated by Cowell et al 2006 Table 4 Vulnerability matrix for sandy coasts/beaches Type of sandy coast/beach Open beach Beach backed by hard protection Sand barrier Sand dunes coastal lake beaches Sand islands Climate change effect Sea level rise & increased waves Increased tropical cyclone intensity Sea level rise & increased waves Sea level rise & increased waves Sea level rise & increased waves Sea level rise Sea level rise and increased storminess Potential impact Loss of beach width and beach amenity. Potential erosion of backing dunes or land if beach totally inundated - Loss of erosion buffer for storms - Intrusion of saline water into freshwater sandy aquifers More intense erosion events in generally low energy environments, wave effects elevated by storm surge Loss of beach width and beach amenity. Potential undermining and collapse of hard protection Potential erosion and inland migration of barrier or barrier breaching - Loss of erosion buffer for storms Potential erosion of foredune leading to blowouts and inland migration of transgressive dunes - Loss of erosion buffer for storms Loss of beach width - Intrusion of saline water into freshwater sandy aquifers Reduction in size and change in shape of island - Intrusion of saline water into freshwater aquifer 2.3 Brief review and identification of gaps Studies of coastal vulnerability of beaches and sandy coasts in Australia can be categorised into three types of study in terms of their detail and scale: 1. national studies relating to climate change which contain references to vulnerability of sandy coastlines 46

52 2. State-based strategic planning documents identifying coastal areas at risk 3. local case studies focusing on specific locations commonly academic/scientific based studies and local government consultancy studies driven by a needs-based approach for assessing risks in local government areas. Examples of these types are illustrated in Table 5. Table 5 Examples of coastal vulnerability studies including impacts on beaches National State Study Funding and rationale Gaps 1) National coastal 1) Commonwealth funded for national vulnerability study Climate Change reporting ) Victorian coastal vulnerability study, ) Victorian Office of the Environment - responding to Greenhouse Challenge of State government 1) not comprehensive, different methodologies used, only ad hoc selection of beaches in some States 1) modelling of 21 beaches only, using Bruun Rule and recession modelling Local 2) Tasmanian Coastal Vulnerability study, ) Collaroy/Narabeen study, ) Tasmanian Dept of Primary Industries, Water and Environment - to provide guide for planning and coastal management 1) academic study scientific inquiry 2) no gaps for the purpose stated - outlines scope for follow up detailed studies - includes all beaches and sandy coasts 1) no gaps for purpose stated 2) Port Augusta local flooding and vulnerability study, ) local government funding response to existing flooding problem and future planning 2) no gaps for purpose stated detailed study for specific purpose limited beach environments From the examples in Table 5 it is clear that coastal vulnerability studies have been carried out by different institutions at different times and for different purposes. Most of these are generalised studies for long sections of coast rather than specific studies on beaches. The most detailed and often the most expensive studies are usually carried out at the local level (e.g. Port Augusta, SA) for specific purposes such as addressing existing areas of flood risk which are then given a high priority for assessing future risk from projected sea-level rise. While local government is most often involved in this type of study there are also a number of similar studies conducted by coastal scientists in academic institutions. Local studies would normally be funded by local government, possibly with State government assistance, private business or sometimes Commonwealth funding in the case of some academic studies. At the state level, the Victorian study (1993) is one of the earlier attempts to grapple with strategic planning issues related to coastal vulnerability from climate change. The study is State-wide and identifies beaches and sandy coasts within its mapping but only provides a rough modelling of impacts on 21 selected beaches. The recent Tasmanian study (2004) is comprehensive in its discussion of vulnerability and the various approaches that can be used to assess the impacts. It takes a pragmatic approach referred to as a first pass which identifies all of the Tasmanian beaches and sandy coasts which are potentially vulnerable to sea-level rise. The Tasmanian study warrants further discussion as sandy coasts represent 21% of the Tasmanian coast identified as potentially susceptible to erosion and significant recession with sea level rise (Sharples, 2004). These coasts comprise 1) open sandy coast shores backed by low-lying sandy plains, and 2) reentrant sandy shores backed by low-lying sandy plains. A further 6% of the Tasmanian sandy coast is also identified as vulnerable but these areas are backed by bedrock so that shoreline recession is likely to be minimal over the next years. At the national level, the early attempt (mid-1990s) at conducting coastal vulnerability studies around the country was funded and coordinated by the Commonwealth but each of the States had a strong influence on how the studies were conducted. This meant that the Commonwealth s aim of using a modified common assessment methodology (Kay and Waterman, 1993) was not followed and instead a number of different approaches were used to suit the individual State governments. Identification of useful case studies emerged but overall this was an ad hoc national study. More recently, the AGO 47

53 has taken positive steps to scope the issue of coastal vulnerability by commissioning discussion papers, holding national workshops and conducting reviews of available methodologies for impact assessment. In particular, background material has been provided in the draft technical and draft discussion papers for the AGO project The Australian Coast: Assessing Vulnerability to Climate Change (Kay et al, 2006a, 2006b) and the draft report from the 2005 expert technical workshop of the same title. These reports provide a review of previous vulnerability studies, different methodologies and the workshop report outlines priority needs (or gaps) for assessment of Australia s coastal vulnerability to climate change. 2.4 Gaps Table 3 of the AGO 2005 workshop report identifies priority needs for vulnerability assessment under 9 headings with mapping, data and analysis at the top of the list. It is clear from the most recent state-based study (Sharples, 2004) that accurate digital elevation data are essential for a national based study. Sharples comments on the spatial accuracy of the Tasmanian digital elevation model (DEM) used in his study which had 25mx25m grid cells with an attributed altitude for the centre of the cell. The spatial accuracy of the DEM varies considerably for different parts of Tasmania, since different data sources were used to construct the DEM in different parts of the state. The most accurate parts of the DEM are constructed from 1:5,000 topographic orthophoto mapping with 5 metre contours but the basic data source was 1:25,000 scale mapping with 10 metre contours. For the latter data source the elevation accuracy is no better than 2m. However, much of the coastal infrastructure development in flood risk areas has the better resolution mapping and according to Sharples (2004) can be expected to be relatively more accurate for those areas. Aerial photography exists for most of the Australian coast dating back to the 1930 s and particularly the 1940 s (Second World War). Some of this photography has been lost because of the lack of understanding of the data contained and/or loss of film quality. This old photography data base should be managed, repaired and consolidated. It allows a comparison of shoreline change (erosion/recession) to be made over a time scale of about 60 years. Changes to the shoreline may be natural, as a result of artificial works or due to sea level rise. Maintenance of this data base is an essential component of background data for distinguishing shore line changes due to sea level rise. 2.5 Climate-related thresholds Climate-related thresholds for beaches relate largely to the impact of sea-level rise but also relates to other factors such as changes in groundwater levels, altered sediment supply, changes in wave approach, and changes in storm intensity and frequency. Sea-level rise as noted above causes beaches to re-adjust their equilibrium to the elevated level. The magnitude and rate of rise are important as is the type of beach (e.g. whether it is backed by a sandy barrier or by bedrock or is a perched beach on a rock platform). The 2001 IPCC report gave a mid-range sea-level rise of 48cm to the year 2100 and detected no acceleration of sea-level rise during the 20 th century. However, recent detailed analyses of tidegauge data (Church and White 2006) indicate that the rate of sea-level rise sine 1993 has been higher than the average 20 th century rate of rise. It is still unclear whether this acceleration of sea-level rise is a short term (i.e. 10 year) change in the rate of rise or is indicative of a change in the long-term trend. Thresholds for the stability of beaches depend on the availability of sediment to replenish the beach so that it can re-adjust itself to a new equilibrium. In some cases such as beaches perched on rock platforms it is possible that the entire beach will be lost once sea-level reaches a critical threshold. In other cases such as the Adelaide metropolitan beaches critical thresholds are reached once the beaches are eroded close to the existing rock protection. Here the natural beach replenishment from coastal dunes is no longer possible because urban development has encroached on the dunes so that hard rock protection and sand replenishment is necessary to maintain what is now an effectively artificial beach system (Harvey and Caton, 2003). In the context of Adelaide s beaches it should be noted that the beaches do not have an equilibrium alignment and the supply of sand to the southern beaches is only about 10% of the net sand volume that may be moved along the beach by the waves. Therefore even if the natural dunes were available to supply sand there would still be beach recession, without sea level rise. In response, the State government has recently developed a strategy for replenishment and 48

54 recycling of sand within artificial beach cells to allow a sufficient buffer for the projected rise in sea level. The additional cost of beach maintenance related to sea-level rise is in the order of an additional $1.25 million per year (DEH, 2005). In other areas, where there is sufficient replenishment sand as a buffer for beach erosion and an altered equilibrium profile (e.g. barrier beaches of the Coorong National Park) there are no immediate critical thresholds. There are many other examples of foreshores where the beach has been isolated from the sand supply, but where even if seawalls had not been constructed, there still would have been no beach. Much of Port Phillip Bay foreshore falls into this category. The implication is that the beaches were not stable when original land development occurred, but the planners of the day did not have this knowledge. The method of managing this natural erosion issue has been to build seawalls (1930 s to 1950 s) and undertake the construction of groynes and beach nourishment (1950 s to the present). Beach nourishment programs have generally been designed to cope with sea levels at the time they were initiated, with some possible recognition of the possibility of and impact of sea level rise. The bottom line is that most beach nourishment projects will be at risk, on a nationwide scale, as a result of future sea level rise. 2.6 Data and research needs There is a need to create a high-resolution coastal digital data set which also has a high vertical accuracy. It is noted that the use of recent satellite data (NASA/JPL s Shuttle Radar Topography Mission [SRTM]) has been used to identify populations living below 5m elevation, that in Australia about 50% of addresses or population are located within 7 km of the shoreline and Tasmania is the state with the largest percentage of its population (45%) living 1 km from the coast (Chen and McAneney, 2006). They estimate that about 6.0% of Australian addresses are within 3 k of the shoreline and at elevations of less than 5 metres. More than 60% of these more vulnerable addresses are located in QLD and NSW (Chen and McAneney, 2006). More accurate digital elevation data would improve the accuracy of these estimates and it is possible to obtain greater precision with the population data using slightly different methodologies. However, the Chen and McAneney study provides some useful estimates of coastal population. It is not clear from this study what proportion of these addresses relate to beach environments. Once accurate digital elevation data have been obtained for Australian sandy coasts it will be possible to use morphodynamic modelling of beaches from coastal scientists such as Cowell, Hennecke and others which can be integrated with GIS datasets to undertake coastal vulnerability assessment and mapping. There is also a need to collate and archive coastal aerial photography, which dates back to the 1930s. This is an important source of baseline data. It is possible to ground truth old aerial photography, sometimes with limited accuracy, but it is the best source of data available. The Western Australian Government has done extensive photogrammetry of coastal; areas to map shoreline change. 2.7 Feasible assessment options Assessment of vulnerability to climate change of beaches requires high-resolution digital bathymetric and elevation data, which currently does not exist for much of the coastline. Historical aerial photographical data should be compiled to provide baseline data on shoreline change. Accurate surveys of coastal bathymetry and terrain elevation could be completed using laser altimetry but this is expensive and survey areas will need to be prioritized. As a first pass assessment at the national scale with a more detail for high priority beaches (high value, known significant risk) rough estimates of vulnerable beaches can be made using geomorphological mapping and knowledge of standard sea-level response models. For second pass assessment more expensive detailed vulnerability assessment requires modeling based on bathymetric and terrain elevation data, sediment supply and wave data. Greater vertical precision is required for digital data input to bathymetric and elevation models. 49

55 CHAPTER 3: Estuaries 3.1 Introduction Estuaries have significant economic, social and environmental values such as fisheries production, recreation and habitat. Of the 979 Australian estuaries, 28% are currently modified or severely modified (NLWRA, 2002). Estuaries are sensitive environments that are already under pressure from human activities. However the effects of climate change are predicted to increase those pressures as well as create additional ones affecting ecosystem processes and flora and fauna habitat condition. Some of these are shown below in Table 6. Estuary services Estuaries contain significant habitats including seagrasses, mudflats/sandflats, mangroves, saltmarsh/samphire, reed, sedge and rush communities and provide sheltered habitat, nursery and spawning areas for fish, crabs, prawns and shellfish. They help filter pollutants, act as buffers to protect shorelines from erosion and flooding and provide food and habitat for birds, fish and other wildlife. Many estuaries are also the focal point for human settlements with all of Australia s capital cities except Canberra located on an estuary. Over 80% of Australians live within 50km of the coast (Australian Bureau of Statistics 1996), yet 70% of Australia s coastline is sparsely populated. Settlement has led to changes to the ecological function and structure of estuaries with loss of habitats, pollution discharges, replacement of natural shorelines with seawalls and other built structures. In NSW, 37% of estuaries have more than half of the land in their catchments cleared of vegetation (Turner et al, 2004). Estuaries also link to unique coastal wetlands and play a significant part in coastal water resources (discussed in later chapters). Table 6 Some Impacts of Climate Change on Estuaries Climate Change Process Sea level rise. Increased temperature Reduced rainfall. Increased rainfall. Severe weather events. Potential Impact Inundation of dry and tidal land. Erosion and breach of protective dune barriers allowing greater marine influence. Increased water temperature makes coastal waters unsuited to sensitive marine species and ecosystems. Increased water temperature allows invasion by pests or disease. Reduced sediment inflows to estuaries resulting in progressive erosion and inundation. Increased sediment inflows to estuaries resulting in progressive infilling and enhanced estuary maturation. Higher reach from storm surge for coastal areas. Salt water contamination of estuaries during storm surge. Adaptive Mechanisms Maintain or establish adapted vegetation cover. Maintain vegetation cover on dunes to slow erosion, stabilise dune blow outs with vegetation. Make provision for vegetation adaptation processes. Make provision for vegetation adaptation processes. Control sedimentation processes through use of vegetation filter strips and appropriate trapping and control structures. Protect dune barriers. Drainage of low lying land, if no potential to develop acid sulphate soils. Vegetate or maintain vegetation cover with adapted species. Revegetate with salt tolerant coastal species. 3.2 Analysis of Climate Change on Estuaries Estuaries are sensitive environments, which are susceptible to subtle changes to physical and chemical parameters, which determine ecosystem structure and stability. For example, they are sensitive to sea surface temperatures, which if increased can lead to changes in both the range and distribution of biota. Table 7 below outlines the assessment matrix for estuaries and impacts from climate change. Table 7 Matrix Assessment of Climate Change affecting Estuaries Climate Related Drivers Sea level Sea level salinity Importance (High/ Medium/ Low) High High Methods for Assessment of Impacts Inundation & tidal prism modelling Water quality modelling Data Required Level & extent of inundation Level & extent of saline intrusion/ Understanding of Sensitivity to Change Good Good Climate Related impacts or thresholds Loss of estuarine vegetation species Loss of estuarine vegetation species 50

56 Climate Related Drivers incursions Near-shore ocean circulation Wave climate waves/ swell/ beach runup Storm surge Coastal wind Hydrological change/flow Importance (High/ Medium/ Low) Low Medium High Low High Methods for Assessment of Impacts Wave modelling Investigation of beach erosion and wave climate Investigation of beach erosion and wave climate Investigation of stratification Environmental flow modelling Data Required changes in salinity Direction and periodicity of currents Beach and estuary entrance berm photogrammetric profiling Beach and estuary entrance berm photogrammetric profiling Water column dissolved oxygen levels Water flow rates and geomorphology data Understanding of Sensitivity to Change Poor Poor Good Poor Poor Climate Related impacts or thresholds Reduction of dune barriers - breaches threaten to open secondary entrances Reduction of dune barriers - breaches threaten to open secondary entrances Reduction of dune barriers - breaches threaten to open secondary entrances Increased variation of water column stratification Loss of estuarine vegetation Increased variation of water column stratification Rainfall/ runoff/ turbidity Tropical cyclones and east coast lows Erosion Water temperature Cloudiness and solar radiation Ocean acidification High Medium High High Low Low Environmental flow modelling Climate modelling Shoreline Audit for erosion susceptibility Water quality modelling Water quality modelling Water quality modelling Rainfall quantities/regularity of events, runoff flow quantities and occurrences Extent/severity and frequency of events Shoreline condition and vegetation coverage/exposure to flows/currents Water temperature range, rate and extent of change Water temperature variation from shading ph levels Poor Poor Good Poor Poor Poor Loss of estuarine vegetation, particularly seagrasses Changed nutrient conditions potential eutrophication from nutrient peaks from floods or less flushing from reduced rainfall. Increased damage to coastal ecosystems Increased bank erosion Reduction of entrance beach berms width and sand volume Loss/change in distribution of estuarine vegetation Loss of estuarine vegetation, particularly seagrasses Loss of estuarine vegetation, particularly seagrasses 3.3 Identification of gaps, including need for integrated assessment Changes in salinity, temperature, sea level, tides, and freshwater inflows to estuaries are considered likely consequences of climate change on estuarine systems. Estuaries are among the world's moststressed ecosystems because of their close proximity to areas of population growth and development. Understanding of regional differences in the physical drivers that will cause changes in estuarine ecosystems and their ecological functions is limited. Uncertainty also exists regarding changes to dissolved carbon, nutrient delivery and pollutant loading, and their interactions. For example, intensive forestry and agriculture that may be implemented as some regions adapt to climatic change could increase the transport of nutrients such as nitrogen and phosphorus to estuaries. Linkage of hydrological models for surface waters with ocean-atmosphere models is needed to integrate marine and terrestrial ecosystem change. Estuaries illustrate the need for an integrated assessment of the likely climate change impacts on the physical-ecological estuary system. 51

57 To support an integrated assessment of coastal vulnerability, the application of a number of models to provide scenarios of environmental change using predicted climate change data may be useful: Use of conceptual models for different estuary types as identified under the National Land and Water Resources Audit and contained within the OzEstuaries database (available at URL: These estuary wide conceptual models can be supplemented by the use of wetland conceptual models that have been developed by the Coastal CRC; Current and historical mapping of coastal wetlands can provide information on past trends to assist in establishing future trends. The Wetland Assessment method used by Elliot et al (2005) would be useful in combination with modelling of substrate responses to factors such as sea level rise, compaction, subsidence, groundwater and plant production processes, reclamation, land use change, nutrient runoff and pollution discharges; Models such as the Simple Estuarine Response Model (SERM) (available at URL: may be useful because it explores the effects of changing point source loads, catchment condition and freshwater flow rate as well as simulating the dynamics of flora and fauna and sediment movement and possible budgets to better understand ecological dynamics of estuaries and their responses to human pressures; Models relating to sediment and nutrient budgets such as SedNet (Prosser 2001) may be useful in terms of constructing sediment and nutrient movement patterns and responses to climate change processes. Regarding the use of these models for assessing coastal vulnerability, it needs to be noted that they may need manipulation and modification to ensure they are properly capable of considering issues associated with climate change processes and impacts. There is no single model available, which can assess estuaries for coastal vulnerability from climate change in an integrated manner. 3.4 Implications for Estuaries Estuaries are complex systems. Limits in knowledge of the current state of estuarine ecosystems will challenge our ability to firstly identify significant natural changes and secondly enable suitable responses to be developed and implemented. To overcome these limitations, a risk assessment approach would be useful, to lead towards an identification and ranking of the environmental, social and economic values of Australian estuaries. This assessment could utilise data held within the OzEstuaries database (available at URL: ). A key principle would be to give priority to those estuaries that are associated with urban settlements where impacts from climate change including sea level rise would affect both built and environmental assets and where impacts may be significant or irreversible if no planning response is initiated. The OzEstuaries website identifies different types of estuaries based on geomorphic characterisations ranging from wave dominated to tidal dominated systems. The National Land and Water Resources Audit Estuary Assessment 2002 identified the condition of Australia s estuaries and categorised them as either near pristine, largely unmodified, modified or extensively modified. The information contained within the Audit and on the OzEstuaries website provides an important collated resource on estuaries at a national level, which is capable of being compared for analysis and embellished through local research data that may be available at a State or regional level. Sources of information for use in undertaking planning and more detailed regional and local vulnerability assessments (second pass vulnerability assessment) may be available from relevant State Government agencies, regional catchment management authorities, local government, universities and other bodies such as the Coastal CRC (see 52

58 3.5 Feasible assessment options A First Pass Vulnerability Assessment for Estuaries Given resources and priorities, a first pass coastal vulnerability assessment for estuaries could involve the following: 1. Using the resources of the National Land and Water Resources Audit s Estuaries Assessment 2002 and OzEstuaries database, choose a subset of Australian estuaries for a first pass vulnerability assessment. Selection could be by criteria such as: Representation from each State and the Northern Territory, and include a small sample from offshore islands; representation from main climatic zones; representation from both pristine and inhabited/modified estuaries; also use a priori expectation of high vulnerability; 2. For the subset, collect photographic and satellite image resources (historical where available and current, to create a baseline of visual information); 3. Map sea level rise for these estuaries using mapped historical changes combined with predicted changes within a vulnerability assessment process outlined by Harvey et al (1999); 4. Run tidal and water quality models such as a combined SERM and SedNet model together with estuary and coastal wetland conceptual models on a small selection of priority estuaries (a pilot study); 5. Conduct a small number of studies of waves/ swell/ beach run-up impacts on a small selection of priority estuaries using a modified Bruun model as used by Sharples (2004); 6. Overlay assessments for run-off (based on a possible altered rainfall regime), water temperature (warmer) and altered tropical cyclone regimes as considered appropriate and supported by expert based assessment.; 7. Map or tabulate the above results in terms of low, medium or high vulnerability, key certainties and uncertainties (determined at completion of the study); 8. For a few relevant and key estuaries, use an expert judgment process to provide implications for human health (e.g. insect vectors), tourism, urban water supply, mangroves, seagrasses and discharge to oceans for potential impact on fisheries or coral reefs or other ecosystems relevant to estuaries and tabulate results A Second Pass Vulnerability Assessment for Estuaries A secondary pass for vulnerability assessment for estuaries would use the outputs from the first pass assessment to establish key data and parameters upon which to focus more detailed regional/local assessments. Regional/local assessment would then use ranking and risk based assessment processes to identify key vulnerabilities. A key need would be differentiation between human induced changes and climate induced changes for estuaries, linked with those assessments undertaken for other coastal habitats such as seagrasses, mangroves and coastal water resources (environmental flows). 53

59 CHAPTER 4: Coastal ecosystems The significant biodiversity contained in Australia s coastal land and marine ecosystems (as well as terrestrial and freshwater ecosystems) is threatened by climate change and this is recognised in the National Biodiversity and Climate Change Action Plan (DEH, 2004, available at URL: A recent report (Hilbert et al., in press) identified many information gaps and research needs necessary to implement the Action Plan for Marine, Estuarine and Coastal Ecosystems, one of the major themes and relevant to assessing coastal vulnerability to climate change (see box). Common needs to assess the impact of climate change on Australia s biodiversity were identified and it would be useful and practical to align the assessment for the coastal zone closely with the Action Plan. Biodiversity and climate change: information needs and gaps Managers of ecosystems require assessments of their economic value - this could be undertaken as part of climate change impact mapping The interactive, cumulative and synergistic impacts of climate change with other stressors needs to be identified impact mapping would be a useful start An acceptable level of change to maintain assigned ecosystem values needs to be determined needing a long term, new research strategy Research priorities for Marine, Estuarine and Coastal Ecosystems include: o Which species are most vulnerable? o What are sensitivities and responses of representative ecosystems, habitats and processes to climate change? o What ecosystem properties and processes confer reliance? o What are the socio-economic impacts of loss of biodiversity? o Which are the key species, communities and ecosystems? o How have ecosystems responded to past climate variability and change? o Which species have the greatest chances of survival from targeted management actions (these may not be the most vulnerable)? o New monitoring tools and methods for conservation planning and design o Baseline information mapping of what is where o Sustained long-term monitoring to identify how key elements are changing 4.1 Mangroves and associated tidal wetlands Introduction Healthy mangroves and salt marshes are critical for sustained coastal productivity because of the high value of the ecosystem goods and services they provide (see Table 8 and also, Costanza et al. 1997, Ewel et al. 1998, Gattuso et al. 1998). In Australia, mangroves, salt marsh and salt flat ecosystems occupy more than two thirds of tidedominated estuaries and deltas (Heap et al. 2004). Mangroves occupy approximately 1 million ha of the intertidal zone of rivers, embayments and islands of Australia, with the majority of areas Features of mangroves The major structural elements of mangroves are woody tree species that have special adaptations to grow in the marine environment (Chapman 1974, Lugo and Snedaker 1974). Mangroves have a high diversity of fauna, algae and microbial communities (Robertson and Duke 1987, Lee 1999, Mumby et al. 2004). Mangroves and other tidal wetlands are threatened by human activities (Adam 1995, Valiela et al. 2001, Adam 2002, Alongi 2002, Rivera Monroy et al. 2004), resulting in a global 35% loss in mangroves since the early 1980s, and 14% loss in cover in Australia from 1983 to 1990 (Valiela et al. 2001). occurring in the tropics, but significant stands occurring in the extra-tropics (Galloway 1982, Spalding et al. 1997). Salt marshes and salt flats occupy an additional 1.36 million ha, with greatest abundance in Queensland, Northern Territory and Western Australia (Chapman 1974, Ridd et al. 1988, Adams 1990, Bucher and Saenger 1991). Table 8 stresses the importance of the ecological good and services mangroves provide. 54

60 Table 8 Outline of major ecosystem goods and services provided by mangroves, salt marshes and other wetlands and processes potentially impacted by global climate change Goods and services Habitat Nursery for fauna Sediment trapping Carbon storage in sediments and biomass Hydrological damping Nutrient cycling Brief review of mangroves Impact Fisheries, diversity Fisheries, diversity Water quality Atmospheric carbon cycling Water quality, protection from storms, cyclones, tsunamis Water quality, coastal waters productivity Climate change factors (exposure) that have the potential to impact mangroves, salt marsh and salt flats Physiological limits to growth: Although mangrove trees are adapted to living in salt water, there are physiological limits to their capacity to withstand inundation, making them sensitive to increases in the frequency and duration of flooding that would occur with sea level rise (McKee 1996, Ellison and Farnsworth 1996). Mangrove productivity is likely to be affected by enhanced CO 2, UVB radiation, air and sea temperature and altered patterns of rainfall (Ball and Munns 1992, Ball et al. 1997, Clough and Sim 1989). Additionally, some common species of mangroves cannot be coppiced, (Tomlinson 1986, Baldwin et al. 2001) and thus mangrove forests may be particularly sensitive to damage from enhanced cyclonic frequency or intensity. Table 9 summarises global climate factors likely to influence mangroves and the key mechanism through which global change will impact mangroves. Table 9 Predicted effects of global climate change factors on mangrove habitats and key references Description of the ecosystem Australian mangrove forests have higher tree diversity in the tropics compared to temperate regions, and in moist compared to arid environments (Duke et al. 1998). Mangroves are characterized by zones of tree species and by strong gradients in tree height, which often decline from tall forests fringing open water or rivers (up to 50 m) to shorter forests on landward edges (<1 m). In arid areas, landward forests are often associated with high intertidal salt flats and salt marsh dominated by succulents (Smith and Duke 1987). Sedge-like salt marshes also occur on the landward edge of mangroves, and are well developed where fresh water inputs are higher (Adams 1990, Bucher and Saenger 1991). Australian salt marsh ecosystems have a high diversity compared to northern temperate salt marshes. The strong spatial patterns in the ecosystem are associated with variation in primary productivity and nutrient cycling (Saenger and Snedaker 1993, Chen and Twilley 1998, Alongi et al. 2002), linked to salinity, inundation, sediment and nutrient inputs, and biological factors (e.g. presence of crabs) (Smith 1992, Saenger and Snedaker 1993, Ball 1998). Aboveground root systems and animal burrows slow water velocity resulting in sediment deposition (Furukawa et al. 1997, Wolanski et al. 2000). Roots bind sediments (Young and Harvey 1996, Krauss et al. 2003) and provide sites for flora (Rodriguez and Stoner 1990), and fauna (Primavera 1996, Loneragan et al. 1996, Robertson and Duke 1987, Skilleter and Warren 2003). Geomorphological setting determines ecosystem function (Woodroffe 1992). Substrates underlying mangrove forests vary from highly organic sediments, fine-mineral silts, to coarse carbonate sands. Mangrove soils have higher carbon contents than salt marsh soils, and both exceed carbon contents of most terrestrial soils making them particularly important in carbon and nutrient budgets (Twilley et al. 1992, Chmura et al. 2003, Alongi et al. 2002, Alongi et al. 2004). Global Change Process affected Likely impact Reference Extreme storms -Forests removed -Recruitment reduced -Reduced sediment retention -Subsidence -Reduced forest cover Woodroffe and Grime 1999, Baldwin et al. 2001, Cahoon et al Increased waves and wind Rising sea level -Sedimentation -Recruitment -Forest cover -Productivity -Recruitment -Changes in forest coverage, depending on accretion or erosion (interaction with sediment stabilisation from seagrass loss) -Forest loss seaward, but effects could vary depending on sedimentation and other factors -Migration landward, dependent on sediment inputs and other factors and human modifications Semenuik 1994 Ellison & Stoddard 1993, Woodroffe 1995, Morris et al. 2002, Semenuik 1994, Cahoon et al. 2003, Rogers et al

61 Global Change Process affected Likely impact Reference -Photosynthesis Enhanced CO 2 -Respiration -Increased productivity, but dependent on -Biomass allocation other limiting factors (salinity, humidity) -Productivity UV-B radiation Increased air temperature Reduced humidity Reduced rainfall Enhanced rainfall -Morphology -Photosynthesis -Productivity -Respiration -Photosynthesis -Productivity -Photosynthesis -Productivity -Reduction in sediment inputs, -Reduced ground water -Salinization -Increased sedimentation -Enhanced groundwater -Less saline habitats -Productivity -Few major effects -Reduced productivity at low latitudes and increased productivity at high latitudes -Reduced productivity -Species turnover -Loss of diversity -Loss of elevation relative to sea level -Mangrove retreat to landward -Mangrove invasion of salt marsh and freshwater wetlands -Reduced photosynthesis -Reduced productivity -Species turnover -Reduced diversity -Forest losses -Maintain elevation relative to sea level -Maintenance of surface elevation -Increased diversity -Increased productivity -Increased recruitment Ball et al Lovelock et al. 1992, Day and Neale 2002 Clough and Sim 1989, Cheeseman et al. 1991, Cheeseman 1994, Cheeseman et al Ball et al Clough and Sim 1989, Cheeseman et al. 1991, Cheeseman 1994 Rogers et al. 2005a, b, Whelan et al. 2005, Smith and Duke 1987 Rogers et al. 2005, Whelan et al. 2005, Krauss et al. 2003, Smith and Duke 1987 Vulnerability Sea level rise Mangroves are rooted in the intertidal zone of low energy coasts. They are thus highly vulnerable to rising sea level. Many of Australia s mangrove swamps occur on broad coastal plains that have slopes of less than 0.5% (Wolanski et al. 1992, Semenuik 1994, Woodroffe 1995). In many settings sea level rise of 0.5 m (SRES scenario A1, B2 2080) will result in inundation of seaward fringing mangroves and landward movement of tidal wetlands. Landward migration of mangroves into salt marshes, fresh water wetlands or agricultural lands (where there are no significant human barriers to prevent this) is highly probable, is known to have occurred in the past (Ellison and Stoddard 1991, Ellison 1993, Woodroffe 1995), and has already occurred in some areas in Australia (e.g. in Australia King Sound, Semeniuk 1994; Mary River, NT; Applegate 1999; southern Australian salt marshes, Saintalain and Williams 1999, Rogers et al. 2005), resulting in significant changes in diversity, ecosystem function and human utilization of the coast (Eliot et al. 1999, IPCC 2002a,b, Millennium Ecosystem Assessment 2005, Nicholls 2004). Mangrove forests may adapt to rising sea level and remain stable if vertical accretion equals or exceeds sea level rise (Cahoon et al. 1999). Models of the impact of sea level rise use geomorphological data (e.g. coastal elevation and barriers to migration), sedimentation rates, and predicted rates of sea level rise to predict changes in vegetation with sea level rise (e.g. Simas et al. 2001). Other climatic and biological factors may interact to affect vertical accretion and thus the sensitivity of tidal wetlands to sea level rise (Figure 5, Table 10, Snedaker 1995, Cahoon et al. 1999, Morris et al. 2002, Cahoon et al. 2002a, b, Rogers et al. 2005). Geomorphology (e.g. limestone vs. mud platforms) will also affect colonisation potential (Semenuik 1994). The current Cahoon model of habitat stability in salt marsh and other wetlands incorporates surface and subsurface processes that contribute to maintenance of wetland surface elevation relative to sea level rise (Table 10). This model is the basis of others that investigate spatial variation in vulnerability and impacts of sea level rise (e.g. Nicholls et al. 1999, Nicholls 2004). This methodology is probably the best available for a first pass vulnerability assessment. 56

62 Figure 5. Model indicating the processes influencing vertical accretion in mangrove ecosystems. Adapted by Diane Kleine from Cahoon et al Table 10. Factors affecting surface elevation and wetland stability SURFACE PROCESSES Impact Interacting factors Rainfall, river flows, sediment availability (catchment Sedimentation + land use) SUBSURFACE PROCESSES Root growth + (soil volume and sediment Factors that affect productivity: Nutrient enrichment, trapping and binding) elevated CO 2, humidity, rainfall, sedimentation Decomposition - Dependent on sediment type, species, tidal regime Deep soil layer compaction/subsidence - Groundwater, tectonic activity Groundwater inputs +/- Rainfall, tidal amplitude Although models and tools to monitor and predict changes in vegetation structure and coverage of intertidal wetlands are improving, our understanding of the functional consequences of these changes remains low. The impacts of sea level rise on tidal wetland fauna, sediment, nutrient and carbon fluxes are currently unknown. Medium to longer term monitoring and research needs impact of sea level rise The Cahoon model and associated surface elevation instrumentation, the surface elevation table (SET), were developed for use in northern temperate salt marshes. A global network of sites ( is testing applicability across a range of sites. There are currently 51 SET installations established in mangrovesaltmarsh ecotones in South Eastern Australia (Rogers 2005), but none in other parts of Australia. SET s are a powerful instrument to understand the vulnerability and trajectory of the elevation of coastal wetlands, and therefore need to be continued and expanded. Data from SETs in South Eastern Australia indicate that mangroves are invading salt marshes in the region largely because of subsidence due to reductions in groundwater inputs associated with el Nino cycles (Rogers et al. 2005a, b). SETs revealed subsidence in mangrove soils in Honduras after a severe hurricane (Cahoon et al. 2003). SET studies in salt marsh and mangroves (Morris et al. 2002, McKee et al. unpublished), and in mangroves in Micronesia (Krauss et al. 2003) have indicated importance of nutrient enrichment and mangrove species type on surface elevation. Cyclones and other extreme events The role of mangroves in protecting coasts from storm and tsunami damage is becoming established (Smith et al. 1994, Danielsen et al. 2005). Storms can have a large impact on mangroves, with total destruction being observed in the Caribbean (Smith et al. 1994, Cahoon et al. 2003), with very slow recovery (Sherman et al. 2001), or none at all (Cahoon et al. 2003). Quantitative data from Australia are sparse (e.g. Bardsley 1985, Woodroffe and Grime 1999). Mangroves can recover providing patches of reproductive trees Most tropical ports in Australia recommend small craft use mangroves as protection in the event of cyclones. For example, from the Port Douglas cyclone protection plan: The creeks and waterways off Dicksons Inlet, within the mangrove areas, offer the best shelter/protection for small vessels ( cyclones.htm). 57

63 remain, and hydrology and sediments are not altered to prevent reestablishment (Smith et al. 1994, Ellison 1998, Sherman et al. 2001). Tree species differ in their responses to cyclones, with some species particularly vulnerable as they are unable to re-sprout (Baldwin et al. 2001). The effects of cyclones on associated fauna are not known. Impacts of storms may be more severe in tropical Australia compared to the Caribbean due to the larger tidal amplitude and likelihood of larger storm surges associated with high tides. Climate change factors that directly affect plant growth The box shows that productivity, carbon storage and nutrient cycling of mangroves are vulnerable to elevated CO 2, rising temperatures, changes in humidity, rainfall, cloudiness, UV-B radiation, river and groundwater flows, and sediment delivery. There are significant gaps in our knowledge of climate changes on plant production and carbon and nutrient cycling and flow-on affects to consumers (e.g. Stiling et al. 1999). These gaps should be reviewed and key research enhanced in preparation for a second phase of a vulnerability assessment. Factors affecting plant growth CO 2, UV-B, water and air temperatures The productivity of mangroves and salt marshes are sensitive to increasing atmospheric CO 2 (Drake et al. 1996, Farnsworth et al. 1996, Ball et al. 1997), although there are few studies to date. In higher plants photosynthesis and growth is often enhanced with increasing CO 2, dependent on other interacting environmental factors (Drake et al. 1997, Poorter and Perez-Soba 2001). Elevated CO 2 had little effect on growth rates under salinity limits, but increased growth under humidity limits (Ball et al. 1997). Data available suggests elevated CO 2 levels may change species patterns, and may mitigate effects of reduced humidity in northern regions. Enhanced UV-B levels can lead to damage to plant tissues. Mangroves have pigments that absorb UV-B radiation within their leaves likely due to their evolution in tropical latitudes where UV-B radiation levels are high (Lovelock et al. 1992). Impacts of enhanced UV-B radiation are most likely in temperate regions, eg, small reductions in photosynthetic rates and altered morphology (Caldwell et al. 2003), large effects on subtidal primary producers, smaller effects on intertidal plants (Day and Neale 2002). Plant and soil biochemical processes will be affected by increases in water and air temperatures. In the tropics, photosynthesis in mangroves is limited by midday leaf temperatures (Clough and Sim 1989, Cheeseman 1994, Cheeseman et al. 1997); at southern latitudes it is limited by low temperature (Steinke and Naidoo 1991). Increases in temperature could thus reduce production in northern sites, and increase production in southern latitudes. Respiration (CO 2 efflux) of sediments and plants approximately doubles with every 10ºC increase in temperature, resulting in reduced carbon gain, increased methane emissions and decreased soil carbon storage (Davidson and Janssens 2006). Mangroves and salt marshes have large carbon stores (Twilley et al. 1992, Chmura et al. 2003), thus increases in temperatures may have negative effects on carbon balance (e.g. Clark 2004). Changes in rainfall, river and groundwater flows and sedimentation Reduced rainfall will have a major effect on intertidal wetlands. Current gaps in our knowledge that prevent accurate development of climate change impact scenarios include limited data on sedimentation in intertidal wetlands (data are only available for a few sites and there are few studies over a range of Species composition and productivity are linked to rainfall, as freshwater input into estuaries and deltas reduces salinity and increases water content of soils (Smith and Duke 1987, Ball 1998). Rainfall also influences groundwater inputs, important in the maintenance of marsh surface elevation (Rogers et al. 2005) and flushing (Ridd et al. 1988). Rainfall and river flows sediments delivered to intertidal wetlands have a positive effect on plant growth within limits (Pzezeshki et al. 1992, Hemminga et al. 1998, Ellis et al. 2004). geomorphological settings) and a poor understanding of how sediment delivery co-varies with rainfall and river flow events. Details of groundwater flows into tidal wetlands, and effects on plant production and sediment processes are also unknown. While expert assessment can be used for a first pass vulnerability assessment, ongoing monitoring and research would be needed to prepare for a second pass more comprehensive assessment Summary of methods for assessing impacts and data and research needs 58

64 The methodology outlined in the box (or some modification of it), which provides a way to measure and integrate important processes, may be useful for a first pass vulnerability assessment. Data from surface elevation table (SET) instrumentation 2 are needed to parameterise the models. Data may be needed from more estuaries than currently available, particularly for different geomorphological settings. Basic data that are available to support first pass vulnerability assessment include estimated areas of mangroves tidal flats and salt marshes (available from OzEstuaries). This would allow first pass estimation of where mangroves have ability to migrate (e.g. those near intertidal salt flats) and where they are constrained. Summary of Nicholls et al approach to modeling impacts of sea level rise on wetlands General assumptions: Regions with small tidal amplitudes more vulnerable than those with large tidal ranges Direct losses of wetlands during sea level rise offset by migration landward unless there is a landward squeeze The model has 2 parts: 1. Vertical accretion (Cahoon 1999) and its response to sea level rise. 2. Wetland migration assessment using coastal geomorphic map to assess whether migration is possible or not. Note: the model has been used to estimate wetland loss due to human activity alone (could also be considered as a baseline for vulnerability assessment). With 0.4 to 1% annual loss 32-62% of wetlands were lost by 2080 without any effects of sea level rise. When applied globally, the methodology suggests a loss of up to 22% of the world s wetlands by 2080, for a sea level rise of 40 cm. By including human destruction of wetlands, losses could reach 70% Feasible assessment options mangroves and associated tidal wetlands Critical gaps for anticipating tidal wetland responses to climate change in Australia and associated priorities are: For First Pass Improve detailed digital elevation models for major mangrove, salt marsh and coastal plains in Australia; Develop/improve the fine scale classification of the coast into typological units based on geomorphological characteristics, and linkage between geomorphological classification and ecological and physical processes; Estimate sedimentation rates in mangroves and other wetlands (and differences from historical sedimentation rates). For Ongoing Monitoring Install Surface Elevation Table (SET) instrumentation across a range of coastal locations to link factors influencing surface elevation, geomorphological setting, and sea level rise to establish trajectories of change in Australian tidal wetlands. For a Second Pass Understand the effects of ground water inputs into mangroves and other tidal wetlands, and their importance to maintenance of surface elevation and primary production. Understand the relationship between climatic drivers (e.g. elevated CO 2 ) and human induced change (e.g. nutrient enrichment) on ecosystem productivity and stability. Knowledge of carbon and nutrient storage in intertidal wetland soils and their sensitivity to climate change drivers (atmospheric changes, sea level rise, disturbance from cyclonic activity). Knowledge of faunal responses to changing intertidal wetland composition and productivity Quantitative understanding of the impacts of cyclones on mangroves, rates of recovery and interactions with other factors (e.g. sea level rise). 2 SET instrumentations are a series of rods and marker horizons that measure surface elevation change relative to sea level rise 59

65 4.2 Seagrasses and seagrass communities Introduction Coastal and estuarine areas are the dominant seagrass habitats throughout much of Australia although extensive reefal and oceanic seagrasses occur in many areas (Kirkman 1997). Seagrasses influence the physical, chemical and biological environments in which they grow, acting as ecological engineers (Wright and Jones, 2006). As productive ecosystems that connect terrestrial, estuarine, saltmarsh and mangrove habitats, seagrass communities are recognized as having a high value globally. Table 11 is a vulnerability matrix for Australian seagrasses. Table 11 Predicted effects of climate change on seagrasses and seagrass communities based on available information Scale Broad-scale Localised Climate change process Increased sea surface temperatures Increased ocean acidity Increased intensity/ frequency of tropical cyclones Increased intensity rainfall/river flood events Changes in ocean currents Sea-level rise Interactions Potential impact Change in seagrass communities $ both latitudinally and with depth Possible loss of intertidal and shallow subtidal species vulnerable to temperature stress, predominantly in tropical regions # Enhanced algal growth, reducing ability of seagrass to compete with algae # Small changes in ph (< 1 ph unit) are expected to have a marginal effect on seagrass photosynthesis Turbulent water motion created by strong storms can lead to physical damage of seagrass environments and seagrass communities $ Salinity more frequently reduced below optimal range for seagrass $ ; turbidity increases potentially leading to reduced light, smothering upon deposition and release of adsorbed nutrients # Physical scouring of seagrass substrate by high water flows more frequent $ Unknown Reduces light available in deeper water, increases habitable substrate in intertidal Unknown Effect on ecosystem processes Shift in associated biota Enhanced or reduced growth, possible death*; loss of species and biodiversity leading to a change in community structure Displacement of seagrasses or reduced growth* No change Localised destruction of seagrass communities*; reduction in seagrass shoreline protection properties Localised seagrass losses*; change in community structure as tolerance range for salinity and light are species specific; nutrient enhanced growth usually favouring algae growth Localised seagrass losses*; long-term recolonisation possible for some areas with species adapted to higher energy environments Unknown Changed depth profiles of seagrass; increased area of seagrass habitat in some locations-especially intertidal (except on rocky or built-up shores); loss of seagrasses at their lower depth limits*; migration of deep-water species # Combined effects of multiple impacts may: exacerbate loss or counteract eachother or be beneficial # # Large gaps remain in our knowledge of these impacts on seagrass communities. $ Can be reasonably predicted from current knowledge but is based on few species/functional groups. Interaction with other impacts associated with global warming still poorly understood. *All impacts leading to seagrass loss or a change in diversity/community structure have potential flow-on effects to associated biota (including grazers, such as dugongs in tropical areas, and commercially important fishery species), but these remain poorly understood Brief review of previous assessments - seagrasses Seagrass occurrence in nearshore and estuarine habitats influences water flow and food web structure (Hemminga and Duarte 2000), and their role in nutrient cycling is an ecosystem service (Costanza et al. 1997; Figure 6). 60

66 Figure 6 Conceptual model of seagrass ecosystem services and climate change impacts on them as a response to climate change for a. tropical and b. temperate regions in Australia. Adapted from Orth et al, (2006) Seagrasses are a critical food source for several mega-herbivores such as green sea turtles, dugongs and manatees, while many other animals such as fish are reliant on seagrasses as habitat (Beck et al. 2001). Reports of losses of seagrasses worldwide are of concern (Orth et al. 2006). Australian seagrass communities are extensive in area and biomass, e.g. the Shark Bay and Great Barrier Reef World Heritage Areas (Walker 2003; Coles et al. 2003). Seagrasses diversity in Australia is amongst the highest in the world (Walker 2003; Coles et al. 2003), and their role depends on their stature and life history (Walker et al. 1999). Carruthers et al. (2002) identified key drivers of seagrass community structure and function in tropical habitats of North East Australia, but there is a need to identify key drivers for a broader range of habitats to enhance our ability to predict future change. Key requirements for seagrass survival Seagrasses require light, nutrients and carbon dioxide along with a substrate to anchor in and an optimum salinity typically of ~35 (Hemminga and Duarte 2000). The requirements of seagrasses for these resources and their tolerance to change in them are species specific reflecting their diversity in structure and productivity. Limitations to these basic components usually result in seagrass loss, no growth, or declines in ecosystem services (Table 12, Orth et al. 2006). Table 12 A summary of seagrass loss events grouped by major region, area lost, and reported responsible mechanism. Region Area lost Major loss mechanism Temperate Minor Environmental Dredging; boating; dune migration Biological Herbivory; introduced species; bioturbation 61

67 Region Area lost Major loss mechanism Event based Storms Moderate Environmental Nutrient enrichment; sediment input Biological Brown tide/algal blooms Event based Storms Major Environmental Nutrient enrichment; sea level rise; high temperature Biological Wasting disease Event based Unknown Tropical Minor Environmental Vessel grounding; sedimentation; aquaculture Biological Urchin grazing; dredging; sediment resuspension Event based Cyclones Moderate Environmental Nutrient enrichment; dredging; sediment resuspension Biological Brown tide; urchin grazing Event based Cyclones Major Environmental Salinity changes Biological Megaherbivore grazing Event based Pulsed turbidity Note: Area lost grouped into three size classes (minor<1.0, moderate , and major >100 km2). Bold type indicates mechanisms also predicted to worsen with climate change. Influences on Seagrass Light. Seagrasses have high minimum light requirements - they are particularly sensitive to reduced light availability (Dennison et al. 1993). Numerous cases of seagrass loss have been associated with the reduction of light (Bulthius 1983; Gordon et al. 1994; Walker and McComb 1992; Dennison et al. 1993; Short and Wyllie-Echeverria 1996; Ralph et al. 2006). Increases in available nutrients promote the development of algal growth or epiphytes growing on seagrasses, both of which reduce light reaching the seagrass (Bulthius and Woekerling 1983; Cambridge and McComb, 1984, Short and Wyllie-Echeverria 1996). Sediments in the water column also reduce light availability (Walker and McComb 1992; Preen et al. 1995, Longstaff and Dennison 1999). Nutrients. Seagrass productivity is typically nutrient-limited (Duarte 1999) and increases in nutrient availability often increase seagrass growth (Udy and Dennison 1997). Expansion of seagrass meadows around Green Island off Cairns since the 1970 s is due to enhanced nutrient levels (Udy et al., 1999). However, nutrient enrichment is typically associated with seagrass loss due to light limitation resulting from algal blooms (above). Abal and Dennison (1996) predicted that nutrient-related impacts on seagrass meadows may result from higher sediment loads associated with river floods. Hence more intense storm events associated with some climate change scenarios would lead to elevated nutrients which may trigger losses. Physical disturbance. In tropical Australia, grazing by dugongs often controls the species within a community (Preen 1995; McMahon 2005). Sediment movement and freshwater due to flooding during storm and cyclonic events can affect the seagrass community present (Preen et al. 1995; Campbell and McKenzie 2004). Lower localised salinities are associated with flooding (seagrasses typically have an optimum salinity of ~35 ). The resilience of seagrass communities is expected to vary greatly with community type and the amplitude of events however little data is available to infer responses. Those species adapted to higher disturbance regimes or to higher energy environments on rocky substrates (Walker et al. 1999) are structurally smaller and rapidly growing. Species which occur in lower disturbance environments such as sheltered bays and estuaries are higher biomass and slower colonising. Disturbance can also affect seed bank reserves (Preen et al. 1995; Inglis 2000). Temperature, CO 2 and ph. Some temperature tolerance experiments suggest limits to seagrass survival in tropical locations (Campbell and McKenzie 2006). Few data are available on the responses of seagrasses to changing ph. Recent data from Kenya suggests the potential for enhanced growth under more acidic conditions although enhanced growth of algal species is also expected (Uku et al. 2005). Habitat vulnerability and adaptability to climate change Coastal and estuarine seagrasses are particularly vulnerable to predicted climate change due to the combined effects of inhabiting shallow water and their susceptibility/proximity to terrestrial influences (e.g. Fourqurean et al. 2003). Responses to change are expected to differ in accordance with the composition of seagrass communities. For example although smaller fast growing species are more sensitive to short term changes in local conditions, these species also have the ability to recover more rapidly once conditions improve (Campbell and McKenzie 2004; McMahon 2005; Walker et al. 2006). In contrast, the loss of large persistent seagrasses may result in decadal time frames for the observation of any recovery as observed in Cockburn Sound, Western Australia following light related loss (West et al. 1989; Walker et al. 2006). 62

68 4.2.3 Identification of gaps associated with predicting the responses of seagrasses to climate change Our ability to understand responses to climate change are still limited (Short and Neckles 1999; Duarte 2002). The flow-on effects to other food web levels are significant: observed large-scale seagrass losses have had catastrophic consequences for larger organisms such as dugong (Preen and Marsh 1995). These effects remain unexplored in many ecosystems. Seagrasses provide habitat and protection for numerous taxa and in many regions these communities are unknown, particularly in the tropics. There is no question that any change in the availability of light to seagrasses will alter seagrass communities. Small changes in light availability due to increased turbidity or sea level may merely reduce the maximum depth to which seagrasses may grow, therefore reducing the total area of seagrass habitat. In the case of increased sea level, this may be partially compensated by the potential for additional habitat creation in shallow/intertidal areas although where the coastal zone has been modified for human activities this is limited. However, light requirements and sensitivity to light reduction are poorly understood for tropical species (cf. Longstaff and Dennison 1999) and virtually unknown for deep-water seagrasses below 15 m. Increasing water temperature will negatively affect shallow water and intertidal seagrass communities (Campbell et al. 2006). However, the ongoing impact of a chronic change in water temperature is unclear as no analysis of the influence temperature plays on seagrass species adaptability has been conducted. The few tank experiments in north east Australia (Campbell et al. 2006) demonstrate in one location that small changes in sea surface temperature (SST) could result in loss of shallow water seagrass but this should be tested more widely. It is speculated that increased SSTs will stimulate algal growth more than seagrasses providing a competitive advantage for algal overgrowth however this remains untested. Pulsed changes in salinity will cause seagrass decline. Some species are more tolerant than others to freshwater inputs and there may be community shifts as a result of changing salinity (both increased and decreased). The occurrence and magnitude of salinity changes will reflect local conditions such as water movement and residence times (i.e. estuary or bay flushing rates). The interaction between salinity changes and community shifts has not been modeled for a wide range of locations. The occurrence of disturbance regimes has been rarely documented. The few studies conducted have provided surprising results with both rapid recovery and complete failure of a system to recover having been recorded (Walker et al. 2006). Given the potential cascade effect of the loss of seagrass habitats a better understanding of disturbance-recovery dynamics is essential to understanding responses to change on a broader scale. The results of changes in multiple stresses are currently vague due to our limited understanding of not only the impacts of these factors in isolation but also their interactions. Connectivity (e.g. Thayer et al. 1984) of Australian seagrass habitats with adjacent mangrove, reef and marsh ecosystems represent the ecological integration of the terrestrial, coastal and offshore marine ecosystems. There is no information on how changes in seagrass communities, or the communities adjacent to them, will affect each other under different climate change scenarios Summary of gaps in knowledge and data While recognition of the importance of seagrasses has continued to foster a strong but small research focus, gaps exist in our ability to predict, specifically, the impact of climate change on seagrasses and seagrass communities due to our current lack of knowledge in the following areas: Seagrass species responses to changing light (in particular tropical seagrasses) and water temperature conditions (all seagrasses). Light requirements and responsiveness to changing light availability of deepwater seagrasses The interactive effects of climate-change related changes in water temperature, ocean acidity, carbon dioxide concentration, and the concentrations of limiting nutrients, nitrogen and phosphorus, on seagrasses. Relative productivity of potentially competitive biota such as macroalgae, microalgae and sponges and their response to changes in limiting resources, such as light and nutrients, under the altered biogeochemical environment. 63

69 The adaptability of seagrass communities (total biodiversity) to change remains untested beyond predictions based on current habitat distributions. The responses of seagrass communities to increase amplitude disturbances such as storms, salinity stress due to flooding and changing nutrient regimes. The flow-on effects of changes to seagrass population and community structure, in particular the associated biota including charismatic species such as dugong, turtle, and commercially important fisheries Feasible assessment options for seagrasses -- first pass Compilations of national seagrass distribution data, species responses to different environmental conditions and disturbances and historical seagrass habitat declines and recoveries would be very useful. A national assessment of the impacts of SST in shallow water seagrass ecosystems and of the impact of sea level rise (SLR) and light reducing factors for seagrasses in different ecosystems should be undertaken. Methods used could be: Utilise current species distributional models to assess thermal tolerance ranges and predict changes in species ranges. (More detailed analysis of shallow subtidal and intertidal seagrass impacts may be required). A sea level rise model could be developed based on physical characteristics of coastal habitats and relating to species growth rate data. 4.3 Corals and coral reefs Introduction A healthy coral reef or mangrove, in the absence of human impact, acts as a self-repairing breakwater with growth in equilibrium with the erosion caused by waves, storms and other processes. (UNEP-WCMS, 2006) Coral reefs have the highest biodiversity of any marine ecosystem and provide significant economic and social goods and services to tropical, coastal communities; they produce disproportionately more services related to human well-being than most other systems, even those covering larger areas (MEA, 2005). Coral ecosystems Coral reefs are the result of a symbiosis with single-celled, photosynthetic algae living within the coral tissue. Tropical corals lay down calcium carbonate to form massive reef structures able to withstand the forces of biological and physical erosion and creating diverse habitats for many other organisms. Subtropical corals can also form coral communities but do not lay down sufficient calcium carbonate to form significant reef structures. The distribution, composition and diversity of coral reefs are controlled by geological and climatological history, ocean circulation, water temperature, oceanic chemistry, light and bathymetry (Kleypas et al 1999) Brief review of corals Australia s coral communities and coral reefs Conditions suitable for coral reef development vary considerably along Australia s coastline with key influences including ocean currents, terrestrial runoff, tidal ranges, water depth and turbidity (see Box). 64

70 Australia s coral ecosystems Information about the general location of coral reefs and communities around the Australian coastline is provided by the meso-scale regionalisation of IMCRA (1998) and marine protected areas statistics (CAPAD; DEH, 2003). Australia, uniquely, has warm, poleward flowing ocean currents on both east (the East Australia Current (EAC)) and west coasts (the Leeuwin Current), bringing warm tropical waters southwards and transport of coral larvae into the Tasman Sea. On the west coast, the Leeuwin Current allows development of diverse marine flora and fauna to high southerly latitudes, including the unique coral reef communities of the Houtman Abrolhus Island system (the most southerly reefs in the Indian Ocean) and isolated aggregations in the Great Australian Bight (Veron, 1986; Veron and Marsh, 1988). Biologists from the Tasmanian Aquaculture and Fisheries Institute recently found a shallow reef covered by coral near Flinders Island off Tasmania. Limiting factors for reef development include lack of suitable substrate along the NW coast and extreme (>10m) tidal ranges and turbid waters on the shallow continental shelf between the Kimberly Coast and Dampier Archipelago (Lough, 1998). There are many coral reefs off the northern tropical coast (NT and Gulf of Carpentaria) but high terrestrial runoff and shallow, turbid waters restrict reef development and the region is less well studied. Recently, Veron (2004 for the National Oceans Office) identified non reef-forming, coral communities off northern Arnhem Land. The Torres Strait delimits the world s largest coral reef ecosystem the Great Barrier Reef (GBR) which extends for 2,000km along the Queensland coast. The warm EAC allows development of coral reefs and communities south of the GBR, e.g. Flinders Reef (east of Brisbane), the Solitary Islands, Elizabeth & Middleton Reefs and Lord Howe Island (the southern-most coral reef in the world (31 o S), Harriott et al 1995). Value of Australia s coral communities and coral reefs Australia s coral and coral reef ecosystems occupy 48,960km 2, the world s second largest area (19%) (Spalding et al., 2001). Globally, coral reefs provide goods and services valued at ~US$375 billion per year (Pandolfi et al., 2005). UNEP-WCMC 3 (2006) highlights that the small total area of coral reef (and mangrove) ecosystems belies their importance with respect to the goods and services they provide, which include: shoreline protection, fisheries, biodiversity, tourism and recreation. The same report estimated the annual value of a healthy coral reef at ~US$100, ,000 per km 2. Although valuation of the goods and services provided by all of Australia s coral reef ecosystems is not available, the economic value of the GBR (from tourism, commercial fishing, cultural and recreational activities, shipping traffic) was estimated at AUD$5.8 billion and accounts for 63,000 jobs (Access Economics, 2005). Protection of Australia s coral communities and coral reefs The health of coral reefs in many parts of the world is declining or compromised by several human pressures (overfishing, destructive fishing, extractive activities, changes in land use and water quality, etc). Twenty percent of the world s coral reefs have been effectively destroyed and only 30% of reefs are at low risk from such local stresses (Wilkinson, 2004). Australia s reefs are in the latter category with probably the best-protected coral reef ecosystems in the world (Bryant et al., 1998) due to our small, relatively wealthy population not dependent on reefs for subsistence and high level of community support for resource management (Wilkinson, 2004) (see Box). 3 United Nations Environment Programme - World Conservation Monitoring Centre 65

71 Protection of coral ecosystems in Australia Marine Conservation Reserves in WA include: Jurien Bay Marine Park (MP;), Marmion MP, Montebello-Barrow Islands, Ningaloo MP & Muiron Islands Marine Management Area, Rowley Shoals MP, Shark Bay MP, and Shoalwater Island MP with proposed Marine Conservation Areas for The Capes, Dampier Archipelago-Cape Preston ( Additional protection for some reefs in WA is provided under the State Fisheries, Environmental Protection and Wildlife Conservation Acts (Spalding, 2001). Commonwealth Marine Protected Areas with coral reefs include: Ashmore Reef National Nature Reserve, Cartier Island Marine reserve, Coringa-Herald National Nature reserve, Elizabeth & Middletown Reefs Marine National Nature Reserve, Great Barrier Reef Marine Park, Lihou Reef National Nature Reserve, Lord Howe Island Marine Park, Mermaid reef National Nature Reserve, Solitary Islands Marine Reserve ( In the NT one marine park, Garig Gunak Barlu, contains coral reef ecosystems. A NT Parks and Conservation Masterplan is being developed ( The Great Barrier Reef World Heritage Area (listed in 1981) is the largest marine protected area in the world (see World Heritage sites, DEH). Stresses are managed by the GBR Marine Park Authority (see The GBRMPA established a $2 million Climate Change Response Programme in 2004, in partnership with the AGO. Nationally, the National Representative System of Marine Protected Areas (NRSMPA) has the goal to establish and manage a comprehensive system of marine protected areas to contribute to the long-term ecological viability. and to protect Australia s biological diversity at all levels. ( In the absence of significant climate change, Australia s current and developing system of Marine Protected Areas and other initiatives would ensure the conservation, maintenance and sustainable use of these ecosystems into the future. There is considerable variation in the extent to which current marine park planning includes climate change. For example, the Management Plan for the Ningaloo Marine Park and Muiron Islands Marine Management Area Management Plan Number 52 ( states For the purposes of developing management priorities, pressures on the values are confined to current pressures and pressures likely to occur during the life of the management plan and considered to be manageable within a marine conservation reserve context. By definition, this excludes global pressures such as climate change. In contrast, the draft NT Parks and Conservation Masterplan, specifically addresses issues associated with the impacts of climate change and, on the east coast, the GBRMPA has a climate change response team. In summary, however, most Australian coral reefs are well protected against most human pressures, both by law and by the capacity to enforce such regulations. Overall knowledge and status of Australia s coral and coral reef ecosystems The GBR contains >360 species of hard coral and >1,500 species of fish, >4,000 species of molluscs, >400 species of sponges, 30% of the world s soft coral species, extensive sea grass beds, internationally endangered dugongs, six of the world s seven marine turtle species (endangered and vulnerable), several hundred species of seabirds and provides breeding grounds for humpback whales from Antarctica ( Coral reefs occupy only ~10% of the GBR shelf and the rich biodiversity of the remaining 90% inter-reefal areas has only recently been documented through the GBR Seabed Biodiversity Project ( Development of networks of highly protected areas that preserve biodiversity increases the resilience of coral reefs to cope with external stresses (e.g. Hughes et al., 2003). The number of reefs under management plans is growing and the implementation and maintenance of effective monitoring is necessary to assess the effectiveness of these plans in a changing environment. 66

72 Monitoring Programs The most extensive long-term coral reef monitoring program in the world is the Australian Institute of Marine Science (AIMS) Long-Term Monitoring Program (LTMP) started in the early 1980s ( This covers a representative sample of GBR reefs but only visits about 5% of the 2,900 reefs of the GBR, as well as some reefs off WA (Ningaloo, Scott Reef and Rowley Shoals). Other agencies and universities conduct additional coral reef monitoring on Lord Howe and the Solitary Islands, Heron Island and some reefs of northern and western Australia (Wilkinson, 2002). There is also community participation in reef monitoring along the Queensland coast ( Other agencies have programmes to monitor particular groups of organisms (eg seabirds, turtles, dugongs) in limited areas and other programmes monitor physical variables (eg water temperature) in some areas. Coral ecosystems along the western Australian coast are reasonably well documented, with some sporadic monitoring. There is, however, a significant gap across much of far northern Australia with little baseline information let alone regular monitoring of the status and trends in coral reef ecosystems. Sensitivity of Australia s coral and coral reefs to climate change Coral reefs ecosystems are at significant risk from climate change due to their high sensitivity and vulnerability (IPCC, 2001), see Table 13. Table 13 Predicted effects of climate change on corals and coral reefs Climate change process Increased sea surface temperatures Increased ocean acidity Increased intensity/frequency of tropical cyclones Increased intensity rainfall/river flood events Changes on ocean currents Sea-level rise Potential impact More frequent and widespread coral bleaching events Reduced ability of marine calcifiers to create CaCO 3 skeletons More frequent, localised destruction of reefs More frequent and possibly wider extent of low salinity/turbid waters Changed distribution of coral larvae dispersal patterns; changed nutrient supplies Changed marine area suitable for corals Effect on ecosystem processes Coral death, partial or full recovery; reduced reproduction; degradation of coral reef structure; flow-on effects to other reef organisms; change in community structure; loss of species & biodiversity. Small increase in area suitable for coral growth. Weakening of reef structure; reduction in reef shoreline protection properties; reduction in habitat for associated organisms; change in community structure; loss of species & biodiversity Localised destruction of coral reef; degradation of coral reef structure; reduction in reef shoreline protection properties; reduction in habitat for associated organisms Localised coral death; flow-on effects to other reef organisms; change in community structure Changes to coral recruitment from connected reefs; important for recovery after disturbances; Increased area of reef habitat in some locations currently limited by sea level (e.g. reef flats); drowning of reefs that cannot keep up. The most obvious effect is coral bleaching due to rising water temperatures. As a result of bleaching, the coral may die, partially recover or fully recover. Another potential impact of climate change on coral reefs is due to the direct effect of increasing carbon dioxide (CO 2, the major greenhouse gas) on ocean chemistry. About 30-40% of anthropogenic CO 2 released into the atmosphere has been absorbed by the oceans and lowered oceanic ph by 0.1. The ph is projected to drop a further by Lower oceanic ph affects the ability of many marine-calcifying organisms to secrete calcium carbonate skeletons and shells (Buddemeier et al., 2004; The Royal Society, 2005; Hoegh-Guldberg, 2005). Changes in ocean chemistry would alter the makeup of marine ecosystems, alter food webs and weaken coral reef structures. Although there is no evidence, as yet, of calcification rate change in corals of the GBR (through analysis of long coral cores; Lough and Barnes, 2000), the potential consequences are considered significant but poorly understood (The Royal Society, 2005). 67

73 What we know about coral bleaching Coral bleaching is not a new phenomenon due to global warming. Corals bleach in response to several environmental stresses. Until the mid-1970s, however, coral bleaching only occurred on small spatial scales. What is new, and clearly linked to global warming, is an increased frequency of mass coral bleaching events where whole reefs are affected. The majority of the world s coral reefs bleached to some extent in and ~16% is estimated to have been destroyed (Wilkinson, 2004). About 40% of the GBR was affected by bleaching in 1998 and ~50% in 2002 (Berkelmans, 2002). Significant bleaching in the southern GBR occurred in Corals live only 1-2 o C below their upper thermal limit and an additional 1 o C results in mortality. The link between unusually warm sea surface temperatures (SSTs) in summer and coral bleaching is clear. ( Coral bleaching is variable and related to factors such as thermal tolerance of species (Marshall and Baird, 2000), light levels, and hydrodynamic processes (eg strong tides, water flows, Nakamura et al., 2003). For the GBR the average SSTs are now ~0.4 o C higher than at the end of the 19 th century. Modelling of future impacts of continued SST warming suggests that by the end of this century, % of the GBR could bleach, possibly annually (Hoegh-Guldberg, 1999; Berkelmans, et al., 2004) and that maintenance of hard coral cover on the GBR would require coral to increase their upper thermal tolerance limit by o C per decade (Wooldridge and Done, 2004: Donner et al., 2005; Wooldridge et al. 2005). Reefs of the GBR have shown substantial recovery after bleaching events, aided by the large scale of this system and availability of coral larvae from reefs upstream. Gradual coral recovery has also been observed on NW reefs, (Wilkinson, 2004). The distribution of reef-building corals is limited by annual minimum SSTs of ~18 o C and rising SSTs may extend the area for coral reef development polewards. This increase in area is, however, relatively small as corals also require shallow, clear water with a hard seafloor and the necessary ocean currents for propagation (Kleypas et al., 1999). Steady rise in sea level is unlikely to be a major problem as Australia s coral reefs have been at current sea level for several thousand years. Corals have high enough growth rates to keep up with projected sealevel rise and higher sea levels would give shallow, reef-flat corals more living space. Higher sea levels would, however, reduce the land area of the many sandy cays and small islands, which are important nesting grounds for seabirds. The present distribution of ocean currents controls many processes fundamental to maintenance of present day coral reefs, e.g. connectivity of larval supplies between reefs. Although there are indications that the southern extension of the EAC will strengthen with global warming (Cai et al., 2005), there is little information available about how ocean currents (e.g. Leeuwin) will change. CSIRO Mk3 Climate System Model (Hobday and Matear, 2006) supports the increased southward penetration and strengthening of the EAC but shows no obvious changes in the Leeuwin Current. Many of Australia s coral reefs are close to land and can be significantly affected by heavy rainfall and associated river flood plumes. Extensive river flooding discharges low salinity, sediment laden water onto coastal reefs. Current projections as to how the highly seasonal and highly variable rainfall and river flow regimes of northern tropical Australia will change with continued global warming are unclear. Tropical cyclones can be destructive to coral reefs. From , 135 tropical cyclones occurred in Queensland waters and all areas of the GBR have been affected (Puotinen et al., Flood plumes 1997). The impact can range from minor The most pronounced ecological gradients on the GBR are between inshore and offshore reefs. Under current climate conditions nearshore GBR reefs experience river flood plumes annually; mid-shelf reefs experience freshwater flood plumes occasionally during extreme flood events and reefs located on the outer third of the continental shelf never experience freshwater flood plumes (Lough et al., 2002). The response of corals to flood plumes depends on salinity and turbidity levels of the plume as well as the length of exposure. The nearshore Keppel Islands in the southern GBR suffered 85% mortality following the 1991 Fitzroy River flood (Chin, 2003). The behaviour of flood plumes along the GBR has been modelled and mapped (King et al., 2001; 68

74 breakage of more fragile corals to dislocation of centuries-old massive corals. Even severely affected reef areas can recover from tropical cyclones as pieces of living coral remain and replenishment with larvae from connected reefs will occur. Recovery may take 5 to 20 years depending on growth rate of corals. Tropical cyclones play an important part in determining the abundance and species composition of coral communities (Chin 2003). There is not a clear picture as to how tropical cyclone location, frequency and intensity will change with global warming, though there are some suggestions that globally there may be signs of the effect of warmer waters on tropical cyclone intensity (Emmanuel, 2005; Webster et al., 2005; Hoyos et al., 2006). Even without significant changes, tropical cyclones and flood plumes will still be occasional sources of localised reef disturbance (Massel and Done, 1993), from which reefs need time to recover. Both the El Niño and La Niña phases of ENSO 4 result in significant climate anomalies in the vicinity of Australia s coral reefs (e.g. Lough, 1994). It is unclear what will happen to the frequency and intensity of ENSO extremes with global warming but they are likely to continue as a source of short-term climate anomalies affecting ecological processes on Australia s coral reefs. Relative regional vulnerability of reefs There has been little research into the relative regional vulnerability of Australia s coral reefs and coral communities to climate change. The long-term impact of an extreme event such as coral bleaching may be greater for isolated reefs than those with high connectivity and abundant larval supplies. Crimp et al. (2004) suggest that the Cairns section of the GBR and adjacent land area was particularly vulnerable because of the combined effects of low elevation, relatively high population, location near a major river system that floods, narrow continental shelf and economic reliance on tourism and agriculture. Australia s coral reefs and communities are clearly vulnerable to global climate change due to their high sensitivity to warming SSTs and changes in ocean chemistry with additional potential impacts associated with changes in river flows, tropical cyclones, ocean currents and ENSO events. Australia s coral reefs and communities will not disappear entirely, particularly given their high level of resilience compared to other coral reef systems of the world. This resilience is a result of lower human pressures on Australia s coral reefs and active management and protection strategies to maintain reef health. It is, however, highly likely that there will be a significant decline in coral populations and lower numbers of associated organisms and a likely shift from coral-dominated communities to reefs dominated by algae (Hoegh- Guldberg, 2005: Lough et al., 2006). Such changes will have a dramatic impact on the goods and services provided by Australia s coral reefs Methods for assessing impacts on coral reefs As we enter an unprecedented climate state, recent geological and biological history gives us little on which to base predictions regarding the future of coral reefs ecosystems. Coral reefs of the future will be fewer and probably very different in community composition than those that presently exist, and these will cause further ecological and economic loss. (Buddemeier et al., 2004). Coral reefs are complex and dynamic ecosystems with high biodiversity, which provide habitats for a wide range of marine organisms, stretching over a considerable depth range. Natural ecosystem dynamics and responses to normal environmental stresses (e.g. tropical cyclones, floods) results, on healthy coral reefs, in natural variations in coral cover and community structure a continual cycle of decline, change and recovery. These dynamics and the scale of Australia s coral reefs make it hard to detect long-term changes in reef health. Regular monitoring (e.g. AIMS LTMP), essential for detecting change, relies on in situ surveys and is expensive both in terms of expert personnel and ship time. There are established methods for surveying coral reefs and coral communities and there are many detailed surveys but these are primarily specific to a particular time and place ( snapshots ) and without the necessary continuity to detect long-term change. Some long-term perspectives on natural variability and change can be obtained by the established methods for analysing long-term growth and environmental records contained in cores from certain massive coral skeletons, which can cover the past several 4 ENSO: EL Niño-Southern Oscillation 69

75 centuries. Remote sensing of the health of coral reefs ecosystems is not, as yet, sufficiently advanced to detect impacts and changes. Because environmental conditions conducive to coral bleaching events can be readily monitored and critical thresholds detected (e.g. GBRMPA; AIMS Automatic Weather Stations; NOAA hotspots ), detailed surveys of the impacts and subsequent mortality and recovery can be initiated (Berkelmans and Oliver, 1999). Similar, reactive, surveys can also be instigated after major flooding or tropical cyclones events. This is possible (given location of resources) for the GBR; such ability for Australia s other coral reef systems is more limited. Give the size, complexity, and dynamics of Australia s coral reef ecosystems, it is impossible to design a program for assessing all potential climate change impacts that would be equally representative, financially viable and include all significant components of the coral ecosystem Identification of gaps Given that warming of just 1 o C may exceeds the threshold of coping capacity for the Great Barrier Reef and other coral ecosystems, it may be too late to avoid substantial impacts to these systems, even with aggressive, early mitigation action. Mitigation. may give natural ecosystems such as coral reefs greater time to adapt. As a result, coral communities may avoid the loss of at least the more heat-tolerant species, thereby maintaining the functions, goods and services of reef ecosystems. (Preston and Jones, 2006). We have a reasonable knowledge of the vulnerability and sensitivity of corals to climate change impacts. We have very limited knowledge of the ancillary effects on associated reef organisms and their separate vulnerability and sensitivity to climate change. For the GBR, this is being addressed with a book coordinated by the GBRMPA Climate Change Response Team and the AGO to provide a comprehensive synthesis of knowledge about the vulnerability to climate change of the GBR ecosystem that should be of relevance to Australia s other coral ecosystems. Aside from corals, topics covered include: plankton, micro-organisms, benthic algae, sea grass, mangroves, benthic invertebrates, bony fish, sharks and rays, birds, marine retiles, marine mammals, pelagic organisms, islands and cays, coastal and estuarine, geomorphology highlighting the complexity of what makes an ecosystem such as the GBR. Ideally, such regional vulnerability assessments are necessary for all of Australia s coral reef and coral communities. Ocean circulation and currents play a critical role in the maintenance and survival of coral reef ecosystems there is a need for detailed, regional scale projections of how such current systems are expected to change. There is at present little knowledge of the relative vulnerability of different parts of coral reef ecosystems (e.g. along the length and breadth of the GBR) and among different coral ecosystems of Australia. There has, to date, been little effort integrating the combined effects of different climate change stresses on coral ecosystems to produce large-scale risk maps e.g. spatial extent and frequency of freshwater flood plumes, spatial occurrence, frequency and intensity of tropical cyclones, spatial risk of coral bleaching, combined with the gradual increase in sea level and reduction in ocean ph Climate-related thresholds Vague hopes that the biology of coral reefs will keep up with the pace of change are not matched by current observations or our understanding of past changes. Evolution is a slow process that is unlikely to keep up with the rapid changes currently being exerted upon the environmental envelope surrounding corals and coral reefs. (Hoegh-Guldberg, 2005). The most clearly defined climate threshold for corals is that associated with coral bleaching which occurs with SSTs 1-2 o C above summer maxima levels projected to be exceeded increasingly frequently over the coming decades. Thresholds for coral mortality are only ~1 o C above those for bleaching. We know that healthy reefs (i.e. those not subject to other human stresses) are more resilient and can recover from mass coral bleaching events but such recovery requires time. 70

76 We also know that localised disturbance and death of corals occurs as a result of reduced salinity associated with extreme flood events and physical damage due to tropical cyclones. Both are likely to add to the stress on some of Australia s coral ecosystems as global warming continues. Thresholds associated with changing ocean chemistry are not, as yet, clearly defined Data and research needs Monitoring of changes in ocean chemistry (cf important overseas examples of BATS, Bermuda Atlantic Time-series Study, a long-term deep ocean time-series of data and HOTS, Hawaii Ocean Timeseries ) Improved modelling of potential changes in oceanic currents in vicinity of coral reefs Improved integrated assessments of combined effects of different climate changes stresses (more frequent coral bleaching, weaker coral structures, more frequent/intense freshwater events, breakage due to tropical cyclones, larval supply and changing ocean currents) on Australia s reef landscapes. Expand monitoring and research to wider selection of coral communities and reefs. Completion of GBRMPA vulnerability assessment other organisms reliant on healthy coral reef ecosystems and habitats. Integration of climate change as a significant factor affecting marine ecosystem protection and MPA design. Assessment of relative vulnerability of coral reefs with respect to location, key climatic drivers and other stresses (e.g. proximity to terrestrial influences) Feasible assessment options coral communities and coral reefs Given the extensive work done on the Great Barrier Reef, a first pass assessment could use this work as a model for other major Australian reefs. In order to assess the degree of threat from global warming, it would be useful to identify possible refugia (i.e. ecologically suitable locations where corals may survive in future) and how much adaptive capacity they might provide to Australia s internationally important reef systems. For a second pass assessment, it should be possible to expand the geographic area of case studies and to undertake more detailed modelling of the bio-geo-chemical environment of corals. Additional routine ocean chemistry monitoring would greatly enhance the utility of the modelling effort. 4.4 Feasible assessment options coastal ecosystems Since work associated with the National Biodiversity and Climate Change Action Plan (DEH, 2004, available at URL: has identified information gaps and research needs for marine, estuarine and coastal ecosystems, it would be useful to align efforts on common needs. Common needs identified under the Action Plan, and recommended for collaborative inclusion in a first pass vulnerability assessment for coastal ecosystems are: An annotated bibliography of current research, publications and information in the grey literature; An accessible, electronic database of relevant information and data (including local, state and federal activities); and Coordination of regional maps (e.g. species distributions, key habitats, protected areas). 71

77 CHAPTER 5: Coastal water resources 5.1 Introduction Increasing population growth within the coastal zone will continue to place pressure on coastal water resources. Demand for water supply to coastal communities as well as continued demand for water for agricultural and rural pursuits will compete for the environmental flows needed to sustain coastal environments, particularly estuaries. CSIRO (2001) climate change projections have increases in temperatures for all coastal regions of Australia and decreases in rainfall for some regions, leading to decreases in streamflow and water availability. Table 14 shows a detailed vulnerability and adaptation matrix for coastal water resources. Note that not all of these adaptation measures would need to be introduced at all locations; detailed studies at precise locations would be needed before specific recommendations for management options could be made. Table 14 Vulnerability Matrix of Climate Change Impacts on Coastal Water Resources Climate effect Potential Impact WATER SUPPLY Sea level rise. Incursion of saline water into fresh-groundwater aquifers loss of supply. Adaptive Mechanisms Re-deployment of groundwater extraction bores. Increased Temperature Reduced rainfall. Increased rainfall storm events. Incursion of saline water into freshwater reaches of rivers loss of supply (upstream extension of tidal limits in estuaries). Redundancy of water extraction infrastructure such as weirs and off-takes by increased tidal influence. Increased water temperature makes coastal waters unsuited to sensitive marine species and ecosystems. Increased water temperature allows invasion by pests or disease. Increase demand for water due to warmer weather. Reduction of flows increased evaporation rates. Increased risk of bushfires in catchments - associated risk of decreased streamflows. Reduced river flows including environmental flows & reduced environmental condition for water harvesting. Flash flooding incapacity of drainage network to cope. Damage to stormwater infrastructure. Increased sewer overflows Increased erosion events. Re-deployment and/or construction of tidal barriers to maintain the freshwater integrity of river reaches or do nothing. Re-deployment/re-development of water extraction infrastructure/installation of protective barrier structures. Make provision for vegetation adaptation processes. Increased pest plant and animal monitoring and control. Introduce water saving measures. Improve water recycling use. Improved fire fighting capacity and resources/increased fuel reduction burning pressures. Introduce water saving measures and improve water recycling use. Protect assets through improved floodplain management/protection. Continuous repairs and/or upgrades. Continuous repairs and telemetry based monitoring of infrastructure network. Control sedimentation processes through use of vegetation filter strips and appropriate trapping and control structures. 72

78 Climate effect Severe weather events. Potential Impact Higher reach from storm surge for coastal areas. Salt water contamination of freshwater reaches of rivers. SEWERAGE AND DRAINAGE SYSTEMS Sea level rise Reduced rainfall. Increased salinity levels due to rising seawater levels resulting in increased infiltration to sewerage network and at wastewater treatment plants. Increased level of poor drainage performance caused by seawater levels backing up drainage systems. Increased potential for corrosion and odours caused in the sewerage network as a result of increased sewage concentrations associated with water conservation. Adaptive Mechanisms Protect dune barriers. Re-deployment and/or construction of tidal barriers to maintain the freshwater integrity of river reaches. Installation of barrier technology to avoid/minimise infiltration. Infrastructure replacement and upgrades. Increased rainfall storm events. Increased risk of pipe failure and collapse due to dry soil conditions. Increased incidence of sewer overflows due to increased rainfall intensity during storms. Flash flooding incapacity of drainage network to cope. Damage to stormwater infrastructure. Infrastructure replacement and upgrades. Infrastructure capacity upgrades. Continuous repairs and telemetry based monitoring of infrastructure network. Stormwater system capacity upgrades. Protect assets through improved floodplain management/protection. Continuous repairs and/or upgrades. Continuous repairs and telemetry based monitoring of infrastructure network. Severe weather events. Increased erosion events. Increased incidence of sewer overflows due to increased rainfall intensity during storms. Flash flooding incapacity of drainage network to cope. Damage to stormwater infrastructure such as underground drains, levee banks, pump stations etc due to higher peak flows. Increased erosion events. RECEIVING WATERS Sea level rise Incursion of saline water into freshwater groundwater aquifers loss of supply. Incursion of saline water into freshwater reaches of rivers loss of supply (upstream extension of tidal limits in estuaries). Control sedimentation processes through use of vegetation filter strips and appropriate trapping and control structures. Infrastructure capacity upgrades. Stormwater system capacity upgrades. Continuous repairs and/or upgrades. Continuous repairs and telemetry based monitoring of infrastructure network. Control sedimentation processes through use of vegetation filter strips and appropriate trapping and control structures. Make provision for vegetation adaptation processes. Make provision for vegetation adaptation processes. Increased Temperatures Increased water temperature makes coastal waters unsuited to sensitive marine species and ecosystems. Increased water temperature allows invasion by pests or disease. Increase demand for water due to warmer weather. Reduction of flows increased evaporation rates. Make provision for vegetation adaptation processes. Increased pest plant and animal monitoring and control. Introduce water saving measures. Improve water recycling use. 73

79 Climate effect Reduced rainfall. Potential Impact Reduced river flows including environmental flows & reduced environmental condition for water harvesting. Adaptive Mechanisms Introduce water saving measures and improve water recycling use. Increased rainfall storm events. Severe weather events. Reduced water quality due to concentrated levels of stormwater quality discharging into river, estuaries and embayments. Increased erosion events. Higher reach from storm surge for coastal areas. Salt water contamination of freshwater reaches of rivers. Ensure appropriate environmental flows are maintained/provided. Control sedimentation processes through use of vegetation filter strips and appropriate trapping and control structures. Protect dune barriers. Re-deployment and/or construction of tidal barriers to maintain the freshwater integrity of river reaches. 5.2 Methods for Assessing Impacts on Coastal Water Resources A key method for assessing the impact of climate change on coastal water resources is the use of catchment related hydrological models (Chiew and McMahon 2002), which require information about daily rainfall and evapotranspiration. Other models such as FLOWS and REsource ALlocation Model (REALM), which can simulate the operation of both urban and rural water supply systems, are important for determining environmental flows and assisting decision making with water allocations through relevant legislative frameworks at State levels. Howe et al. (2005) used a rainfall-runoff model (AWBM; Boughton, 2002). All of these models are quite complex to use and are appropriate for detailed regional studies. Recently, Jones et al. (2006) developed a rule-of-thumb technique to estimate potential changes in runoff due to climate change. This may be more suitable for broad-scale assessments. A number of regional approaches have been undertaken for urban and rural water resources (see Table 16). These regional strategies are being supported by river catchment specific Streamflow Management Plans (Victoria) and Water Sharing Management Plans (NSW). Groundwater resources are also being managed through Groundwater Management Regions and planning processes. The effects of climate change are starting to be considered in strategic investigations, but the uncertainty regarding regional climate changes has restricted significant consideration to date. This situation is changing, as exemplified by Howes et al. (2005). 5.3 Implications for Coastal Water Resources The main implication for coastal water resources remains increasing pressure for water usage from urban, rural and environmental purposes. Critically, thresholds for environmental flows, particularly for estuaries, are required to sustain the health and productivity of ecosystems. The demands for water along the coast will compete over potentially dwindling sources of supply unless adaptive measures are instituted such as water savings and demand reduction strategies. 5.4 Review of previous vulnerability studies A number of studies have examined the possible effect of climate change on water resources in Australia (Table 15) over a considerable number of the regions of Australia. Their results could form the basis of a first-pass vulnerability assessment for coastal water resources. Table 15 Studies of climate change impact on water flows in coastal Australia Study Scenario Region Effect on runoff Chiew and McMahon (2002) CSIRO (1996) North-east coast -5 to + 15% by 2030 East coast -15 to +15% by 2030 South-east coast -20 to 0% by

80 Tasmania -10 to +10% by 2030 South-west coast -25 to +10% by 2030 Chiew et al. (2003) Several models Eastern Australia -6 to -3% by 2035 South-west Australia -7% by 2035 Howe et al. (2005) CSIRO (2001) Central coast Victoria -11 to -3% by 2025; -35 to -7% by 2050 A confounding factor for climate change impacts is increased water demand caused by rapid population growth in coastal regions. This is the main mechanism causing water resources to become vulnerable, with the impact of climate change often considered a secondary effect. This has been recognized in the recent water strategy documents that have been compiled in all States. Table 16 summarizes the conclusions of these documents. Vulnerability might be defined in this context by the need to invest in major infrastructure or to implement major water conservation measures. Note that not all of these recommendations have been adopted. For example, the NSW government has recently proposed that a desalination plant will be built in Sydney, despite NSW (2004) recommending this only as a last resort. This decision has not yet been finalised, however. In contrast, the government of Western Australia has approved a desalination plant as part of their core strategy for water infrastructure in the Perth region. Even so, some future scenarios of climate change indicate that some additional infrastructure beyond this may be necessary. Changes in land use may also influence water supply. Future fluctuations in demand for coastal water resources may be caused by increased rural residential development and increased development of small dams capturing water runoff. Increased timber plantation and harvesting activity, particularly within areas where timber production results in significant landscape character changes, may alter hydrological patterns, impacting on water supply to rivers, lakes and wetlands. In addition, the studies in Table 16 refer largely to maintaining urban uses of water, but a large portion of water allocation to coastal users goes to irrigation (e.g. WRSC 2002). Table 16 Recent water strategy documents Study Region Climate change effect Major infrastructure recommended WRSC (2002) Victoria Implied a conservative water strategy needed None; water conservation measures NSW (2004) Sydney Uncertain None; management and conservation measures South Australia Assumed reduction in water None; management and conservation Adelaide (2005) supply of 10% by 2025 measures Current plans for desalination plant Western Australia Scenarios of future reduction in and increased groundwater use, but South-west WA and CSIRO (2005) water availability some additional infrastructure may be required Howes et al. (2005) Melbourne See Table 15 QDNRM (2006) South-east QLD Notional 15% cut in water availability for scenario purposes Conservation and management; some infrastructure may be required after 2020 Major new infrastructure required 5.5 Gaps and critical thresholds The study by Howes et al. (2005) is the most detailed to date, but the methodology used in it has not been applied uniformly in other locations in Australia. In the context of water resource issues, a critical threshold might be whether considerable additional infrastructure is required to guarantee minimum flow rates of water to users. Unfortunately, it cannot be guaranteed that individual State authorities have used nationally-consistent methodologies and approaches to assess this need. A first pass vulnerability assessment may therefore utilise previous impact studies (as summarised in Table 15) overlaid with a nationally consistent assessment of the resulting vulnerabilities to particular water flow rates. 75

81 5.6 Feasible assessment options First pass vulnerability assessment Summary of previous assessments of changes in environmental flows plus Jones et al. (2006) estimates, overlain with estimates of current vulnerability. 76

82 CHAPTER 6: Coastal infrastructure 6.1 Introduction Coastal infrastructure includes buildings, roads, maintained parklands, coastal defence works all of the infrastructure required to support coastal communities. This section summarizes previous work that has been done on assessing the vulnerability of this infrastructure to climate change, and identifies areas where more work is required. Table 17 shows a vulnerability matrix for coastal infrastructure. Naturally, a crucial climate change variable for coastal infrastructure effects is sea level rise, as increased sea level can potentially lead to increased coastal erosion and coastline recession (Bruun 1962; Stive 2004; Zhang et al ). Other impacts could come from the effects of changes in wind climates (speed and direction), temperatures, and rainfall intensities. Table 17 Vulnerability matrix for coastal infrastructure Infrastructure Climate change effect Potential impact Coastal dwellings Sea level rise More frequent inundation and commercial Increased tropical cyclone property winds More frequent damage, both wind and wave (storm surge) Little impact expected under normal conditions because Sea level rise facilities are designed for maximum historical tides plus a Ports and harbours; airports; coastal refineries; marinas Offshore platforms Roads Subterranean power lines/cables Storm water Maintained parkland Coastal defence structures Submarine pipelines Beaches Island communities (e.g. Torres Strait) Canal estates Increases in wind/wave heights Increased frequency of cyclonic winds and higher storm surge Increases in wind/wave heights and current speeds Sea level rise; increased peak rainfall Sea level rise Increased rainfall intensity Sea level rise Sea level rise Sea level rise Sea level rise and increased wave heights and bed currents during storms Sea level rise & increased waves Sea level rise and increased storminess Sea level rise storm surge event. Possible delays to ship movements with consequent disruption to ship schedules. Can affect road/rail access & product storage through wind, rain, water effects. The combined effects can also constrain production (in open cut mines, etc). Also potential damage to breakwaters, navigational aids, etc. Possible planning, safety issues for small and pleasure craft. More likelihood of damage or inundation. Shipping delays. Delayed ship loadings caused by more frequent shutdowns. Delays to support vessel functions. More frequent inundation, damage to structures protecting roads More frequent inundation; increased seepage resulting in need to protect cables More frequent flooding, combined with more frequent seaborne inundation Drainage rates/volumes decreased Erosion, coastal recession, undercutting of maintained paths/walkways More frequent overtopping of sea walls Coastal recession would require shoreward extension of jetties Seawalls and jetties may need to be raised Breakwaters may become less effective due to higher sea levels, or may fail due to larger waves Pipeline may need additional stabilization anchors, rock backfill or burial to remain stable Loss of beach width and therefore beach amenity. Potential erosion of land if beach totally inundated Loss of erosion buffer for storms Islands are generally low lying so that sea transport facilities need to have increased levels (ramps, jetties) and land backing levels need to be raised Originally built with minimal freeboard. Land levels may need to be increased when housing rebuilt 77

83 6.2 Methods for assessing impacts on infrastructure Climate simulations are a primary method to assess the impact of climate change on infrastructure. This section focuses on the impact models that are used once the basic climate change scenario has been constructed. Coastal erosion is the main mechanism by which climate change could have an impact on infrastructure. Methods for assessing coastal recession have been detailed in Chapter 2, which outlines the importance of both sea level rise and sediment variability. As mentioned in Chapter 2, digital elevation data are crucial for assessing the impacts of sea level rise. In the first pass vulnerability assessment of Sharples (2004), fundamental vulnerability factors were first identified for each shoreline type, and the vulnerability assessment was then performed based upon these factors, using a digital elevation model. The assessment was limited by the vertical resolution of the DEM, which was only 2 m, insufficient for detailed, site-specific evaluation of vulnerability. Digital elevation data must be very accurate for assessment of vulnerability to sea level rise. The best source of early data on land levels and shoreline position is historical aerial photography dating back to the 1930 s. Once coastline recession has occurred, the adjacent infrastructure may become exposed to increased episodes of sea flooding and wave damage. GIS techniques are needed to assess the cost of impacts of coastline recession (e.g. Hennecke et al. 2004). Such techniques would be very site-specific, however, and would not necessarily be needed for a first-pass assessment of vulnerability. Rather, they would be useful for more local studies later, once vulnerabilities have been identified. Some regions may be affected by increased peak wind speeds, especially tropical areas (e.g. see Walsh 2004). The impact of increases in wind speeds may be assessed by wind damage models. The prediction of damage (in dollars) from extreme winds requires two major inputs: hazard models and vulnerability curves. The hazard model focuses on the wind storm hazard itself, and makes use of historical meteorological data and statistics to predict potential wind speeds at a site into the future. Vulnerability curves attempt to predict building (and sometimes contents) damage, given the occurrence of a particular wind speed. The possible effect of climate change on increased wind speeds is primarily reflected in the hazard model. Vulnerability curves for a building are affected by a number of factors: e.g. building geometry (especially the roof), and material and type of construction. However, the major factor is the age of the building, and the building codes and standards in force at the time of construction. Vulnerability models are usually expressed in the form of the expected fraction, or percentage, of building value destroyed, given the occurrence of a maximum wind speed during a severe storm. The latter is usually taken as a maximum gust speed. If the vulnerability curve for a single building is of interest, the gust speed at the top of a building (e.g. average roof height) would normally be used. A vulnerability curve for a population of buildings would be based on a wind gust speed at a standard reference position, such as ten metres height in open terrain. An increase of tropical cyclone strength due to global warming has a potential to increase significantly the level of damage experienced in coastal regions in Australia. For example, the design wind speeds for the coast of Queensland and Northern Territory are equivalent to Category 4 cyclone levels, according to the Australian standard for wind actions, AS/NZS1170.2:2002. Consequently, a genuine Category 5 cyclone at landfall on these coastlines would be expected to produce extensive wind-induced damage. A first-pass vulnerability assessment of potential wind damage might take the form of the identification of regions where projections indicate possible increases in wind speed, combined with an assessment of whether these projected changes would exceed design standards for this region. Preliminary work along these lines has been performed by Walsh et al. (2001). Increased rainfall intensity in some locations may cause storm water infrastructure to be flooded more frequently. Methods to assess this effect would be highly site-specific, as is storm-water drainage capacity. One way to assess vulnerability may be through a survey of members of peak professional organisations such as the Stormwater Industry Association, in order to identify locations that are vulnerable to flooding in the current climate, and from there determine whether they may become more or less vulnerable in the future. 78

84 At a more local and specific level, the interaction matrix approach recommended by the National Committee on Coastal and Ocean Engineering (2004) provides a way of identifying possible hazards for a specific location. It may be too detailed for a first-pass assessment, however. Many coastal locations are vulnerable to storm surge. Storm surge models can be used to assess the likely hazard from increased sea level rise, combined with changes in wind climate. Estimates of storm surge hazard, however, are highly site-specific, in that to obtain an accurate estimate of storm surge height, detailed information is required on land topography as well as ocean depth, which in practice can be quite time-consuming to obtain. On the other hand, much of this work has already been completed for many locations along the Australian coastline (e.g. Harper 1999; QDNRM 2004), so a first-pass vulnerability study may simply involve compilation of those studies into a coherent national picture. 6.3 Brief review of previous vulnerability assessments and identification of gaps Wind damage studies The first vulnerability curve and risk model for cyclone damage to housing in Australia was developed by Leicester (1981). Walker (1995) developed some empirical curves for Queensland housing for the insurance industry. Since then various other insurance and government groups have developed their own in-house vulnerability models. These curves (percentage damage versus gust wind speed) typically have an S shape with little damage below a certain threshold, then a rapid increase just above the nominal design wind speed. The vulnerabilities of other infrastructure structures, such as those in petrochemical plants, are more difficult to determine, because of the uncertainty in the coefficients in converting wind speeds into wind pressures and forces on the structures. Generally, much less effort has been devoted to the determination of these coefficients for open structures in wind tunnels than there has been for closed buildings. There have been many evaluations of severe wind risk in the current climate (e.g. AGSO 2001). There has been less work performed on wind risk in a warmer world. Comparison of wind return periods in a warmer world compared with existing design standards was detailed in Walsh et al. (2001). It was noted that in parts of northern Queensland, existing design standards might be exceeded in a warmer world under plausible climate change scenarios. Little progress has been made since then on improving the climate change scenarios that dictate the precise amount of future vulnerability Ports and harbours, marinas, and coastal airports Note that harbours here refers to the physical infrastructure around harbours and not to the actual water itself. Queensland Transport (1999) assessed vulnerability of Queensland transport infrastructure, including ports, to climate change. Additional assessments on the vulnerability of coastal infrastructure were undertaken by QDNRM (2004b). While specific case studies of the vulnerability of ports to climate change have not been performed, ports have generally used the National Committee on Coastal and Ocean Engineering guidelines (NCCOE 2004) to make allowance for climate change effects. Major new port infrastructure is thoroughly assessed for the impacts of climate change in the design phase. These studies are often documented in Environmental Impact Statements if one is prepared. For example, the proposed new offshore wharf structure and expanded coal terminal in the Port of Abbot Point in Queensland (WBM, 2006) studied a number of greenhouse potential impacts. The new facilities were designed for expected water level changes predicted over the next 100 years (conservatively estimated at 0.2 metres to 0.5 metres), plus cyclonic events that may occur at a one in 100 year frequency. New port infrastructure therefore is well prepared for the impact of climate change. 79

85 There is still significant port infrastructure in Australia more than 20 years old. Older port infrastructure has generally been designed for peak tidal events and expected storm surges. During normal conditions, this still provides a significant height buffer over the sea level change expected in the next hundred years. However, older infrastructure may have an increased frequency of impact over time in extreme storm surge conditions. Temporary damage to infrastructure or short-term interruptions to operations may occur, but ports will generally accommodate the climate change well. As new infrastructure is built to replace older infrastructure, ports will continue to improve their ability to manage the impacts of climate changes. Port facilities need adequate water depth. Thus sea level rise should be of benefit, and most ports have constructed their wharves to allow approx. 2-3 metres deck clearance above the expected highest tides, Changes to sediment transport due to changes to ambient flows or increased storm frequency and/or intensity may lead to requirement for more frequent maintenance dredging with associated economic and environmental impacts (e.g. dredge plumes) Refineries are often located in low-lying, coastal regions and may be potentially vulnerable to sea level rise. PB Associates and AGO (2006) concluded that the potentially vulnerability of Australian refineries to climate change was low, however. Some of Australia s major airports are located in low-lying regions immediately adjacent to the coast: Sydney and Brisbane are two of these. Runways at Sydney Airport have been built on reclaimed land that presently sits only a few metres above sea level under normal sea level conditions. The vulnerability of Brisbane Airport to storm surge was evaluated before its construction (BBW, 1979), but to our knowledge no assessment of its vulnerability has been performed due to sea level rise. Note that the DEM data for Brisbane used by AGSO in its vulnerability assessment of South-East Queensland (AGSO 2001) pre-dates the airport and the Fisherman Island port area, both of which have been considerably filled Buildings (industrial and commercial; residential) The main threat to coastal built infrastructure is shoreline recession, as detailed in Chapter 2. Many studies have assessed the vulnerability of portions of the Australian coastline to sea level rise, but few have explicitly used detailed GIS systems to assess the resulting impact on infrastructure. Hennecke et al. (2004) performed such a study for Collaroy/Narrabeen Beach in Sydney. This study explicitly assessed the monetary cost of coastal recession and sea level rise, through use of a GIS and coastal simulations. This level of detail would be difficult to obtain nationally, yet it is essential for evaluating the actual cost of these effects at the local scale. Storm surge can affect built infrastructure, and changes in storm surge climate are one consequence of sea level rise. In some locations, this may be combined with increases in surface wind speeds, which will exacerbate the problem. Previous studies include AGSO (2001), McInnes et al. (2003) and Hardy et al. (2004), but there are others for locations around Australia. These studies have used state-of-the-art storm surge models combined with estimates of sea level rise, usually simply taken from IPCC estimates of global sea level rise, often combined with an estimate of local land/sea movement due to geological effects. Subsidence, being an extremely local phenomenon, is usually not included. Some studies (GEMS 2005) also specifically considered impact of sea level rise on wave runup Roads and bridges Coastal roads in particularly low-lying regions may be vulnerable to climate change (Austroads 2004). The causes of vulnerability would be similar to those for buildings, although bridge infrastructure is particularly long lasting, with design lifetimes of 100 years, which implies a longer planning horizon. A vulnerability assessment of coastal bridges would require first the identification of bridges in vulnerable locations, which to our knowledge has not been done comprehensively for all of Australia. 80

86 6.3.5 Subterranean infrastructure (storm water, power lines) Recent work has suggested, although not with particularly high confidence, that global warming will lead to an increase in the magnitude of severe rainfall events. The resulting impacts on urban drainage have been assessed for some regions of Australia (Smith 1999; Abbs et al. 2000). These studies involved the use of rainfall/ runoff models, combined with detailed information regarding the impact of flood heights on the infrastructure at a specific location. Coastal vulnerability of subterranean infrastructure may be exacerbated in some locations by the combination of increased high rainfall events and increased seaborne flooding caused by sea level rise Non-built infrastructure e.g. maintained parkland The vulnerability of non-built infrastructure is similar to the vulnerability of undeveloped coastlines or beaches (see Chapter 2), with coastal recession the main impact Coastal defence structures (sea walls, groynes, breakwaters, jetties) It appears that few studies have been performed on the specific vulnerability of coastal defence structures; by definition, these structures are built to last. The real question is whether they would become less effective under certain future conditions. A sea wall that is regularly overtopped provides less protection than one that isn t. Coastline recession in some locations may require the shoreward extension of jetty structures. Breakwaters and groynes may become less effective due to changes in coastline orientation. Coastal defence structures have been built along the foreshores of most population centres and Government Defence facilities. Large portions of Port Phillip Bay, Adelaide metropolitan beaches and Brisbane metropolitan beaches have been protected from further erosion by the construction of seawalls. Seawalls or other protective structures have been built to protect historical defence facilities such as at Point Nepean and Swan Island in Victoria, Cockburn Sound and Onslow in W.A., Darwin Patrol Boat Base and naval facilities in Port Jackson. Elsewhere, large sections of the foreshore have been protected by coastal structures, though this has not always been a wise decision due to subsequent unintended impacts on coastal processes such as sediment transport. Examples occur at Lonsdale Bight, Portland and Grantville (Western Port Bay), Victoria; Sandy Bay, Tasmania; Townsville (now rectified), Qld: and Geraldton, W.A., which is now being rectified Submarine infrastructure (e.g. pipelines) Infrastructure located on the seabed is susceptible to changes in sea levels and storm intensity and frequency. The combined effects of changes to the wave and bed currents may result in increased forces on the infrastructure and may increase the mobility of seabed sediments, resulting in either scour or the undermining of the infrastructure. Increase in sea level will increase local wave heights for a given level of atmospheric forcing, but bottom effects (orbital wave velocities) may be attenuated by the concurrent depth increase. Most pipelines have stabilization in the form of anchors and rock covering, or burial by trenching. Present practice tends to exclude a direct assessment of the implications of sea level rise and other associated Greenhouse implications. Fortunately, the current practice in the oil/gas industry is to allow for the 10,000 year return period event in their design development therefore for current or recent projects adequate consideration of sea level and climate change impacts are included. However, for older, ongoing production facilities this may not be the case. A review should be undertaken of existing submarine infrastructure to determine whether it has design recognition of the impacts of sea level rise and associated increases in wave and current strengths. 81

87 6.4 Planning issues and vulnerability assessment Introduction Methods for addressing the impact of climate change on the coast include not only technical evaluations. There are several policy issues that need to be addressed, particularly when coastal infrastructure (e.g. Figure 7) is involved. Even if data and technical information were perfect, there would still be gaps in our management of coastal resources due to governance issues, and hence potential vulnerability. Planning systems and schemes All State Governments address climate change and its relationship to coastal vulnerability under either a coastal policy or natural resource management plan. Planning schemes provide the statutory policy direction to guide planning decisions on land use and development and specify the information and the scope of assessment required for land use and development proposals. The planning schemes establish land use zones, development overlays or policy schedules which direct where different forms of land use can occur and what standards or criteria must be satisfied for development activity. Figure 7. A coastal town that shows some of the planning issues and potential vulnerability as a result of a combination of past planning, seachange pressures and likely coastal impact of climate change Source: Climate Change and the Coastal Communities of NSW and SE QLD. Integrating greenhouse with strategic, urban and rural planning. - Des Schroder DIPNR (NSW), 3 June '05 - Regional Forum on Climate Change & Coastal Communities, Lismore Drivers for Planning There are a number of key drivers on the ability of land use and development planning to deal with coastal vulnerability arising from climate change (see Box). Drivers for and constraints on planning for coastal vulnerability arising from climate change 1. Responsibilities in a federal system: Because planning is a state government responsibility, there is limited involvement or direct influence of the Federal Government on planning, legislation, policy or administration. Also, there is a fragmentation of planning policy on climate change-related coastal vulnerability and adaptation measures between state and local governments. 2. Information for planners: Information supplied by scientists is often not in a useable form, with the scientific uncertainty of climate change forecasts and coastal vulnerability a problem for communities and council representatives. There are few guidelines and tools that planners can use to address coastal vulnerability due to climate change. 3. Resources at local government level: There is a lack of resources and adequate expertise for local government to undertake coastal vulnerability studies and consequential planning scheme amendments. 4. Decision-making horizons: Short operational horizons constrain decision makers from viewing issues in the long to very long term. This is compounded by the level of uncertainty and the scope and cost of conducting investigations (Coastal Vulnerability Case Studies, (Waterman 1996). 5. Lack of information about adaptation: There is little local information on how coastal ecosystems may cope and adapt to climate change in order for appropriate planning responses to be developed. There has been limited cost benefit analysis to assess adaptation options/measures on an environmental, social and economic basis. As a result of constraints identified in the box, to date there has been a limited response to coastal vulnerability caused by climate change. The majority of planning that has been undertaken relates either 82

88 to addressing flooding issues through building floor level heights and identification of land areas liable to flood hazard; or to identification of coastal erosion hazard zones (erosion lines) usually based on 50 year scenarios e.g., Gosford City Open Coast Beaches Coastal Management Plan (WBM Oceanics, 1995). Moreover, while State coastal plans may recommend adoption of strategies to combat sea level rise and other impacts of climate change, local councils may not necessarily include such measures in their planning schemes. For example, a recent survey (Hebert and Taplin 2004) showed that less than 30% of all Sydney Coastal Councils had any reference to climate change in their planning and management policies. Thus a national audit of local planning schemes could serve as an initial vulnerability assessment for planning Gaps in planning that affect vulnerability Plan making needs to identify, assess and seek to implement appropriate adaptation strategies/ measures for climate change induced coastal vulnerability (See Box). General principles for planning for coastal vulnerability due to climate change: Identify the key vulnerable areas or communities threatened by coastal vulnerability due to climate change. Evaluate effects and identify appropriate adaptation responses for vulnerable areas. Develop standards for methodologies employed to quantify risks Co-ordinate coastal vulnerability and climate change data - provide information to assist decision-makers in risk assessment and make reference to existing documents, maps, overlays, digital data and studies. Identify tools (planning codes, incentive programs or landholder agreements) to facilitate or enhance vegetation linkages currently in private ownership, particularly through climatic regions. Recommend that States develop planning policies for climate change along the coast. Make recommendations for incorporation into tools such as planning schemes, local laws or guidelines/codes of practice specifically addressing climate change issues. Strategic planning should be proactive, to reduce costs associated with asset protection and repair, interference and dislocation of community lifestyle and amenity, loss of infrastructure and community facilities such as protective structures, water and sewerage infrastructure, roads and sporting facilities. A related benefit of strategic planning may be a reduction of insurance cost increases. Planning therefore has considerable scope to increase adaptability and reduce vulnerability of communities. A comprehensive vulnerability assessment that included consideration of adaptive capacity may therefore include consideration of existing gaps in planning needs Planning options for Coastal Vulnerability With respect to planning for climate change, State and local governments who are responsible for planning do have some issues to address, including co-ordinating how they establish the thresholds for vulnerability and the appropriate courses of Gaps in planning needs (for planning to reduce vulnerabilities) 1. Risk management methodologies to assess and prioritise action for responding to coastal vulnerability impacts, coupled to cost/benefit analyses of adaptation options. 2. Strategic plans to include climate change assessment and adaptation options. 3. Improved technical capabilities of planners: an improved understanding of the nature and extent of vulnerability to events such as flooding, landslides, coastal inundation, erosion, and ecosystem changes. 4. Access to data, information and implementation tools by planners, which are relevant to coastal vulnerability risks. action that may be required to avoid, minimise and manage climate change processes and effects. The key information required from a planners perspective is how far the sea will reach landward (and how often) so that setbacks and buffer zones can be established with credibility that is defensible in forums such as the Land and Environment Court, VCAT, and so on. A national first approach to assessing climate change coastal vulnerability is critical to identify key areas and environments that would be subject to impact. This would be followed by a second, more detailed and specific assessment of vulnerability which targets areas where impact of climate change on the coast will affect communities. Local governments, through planning schemes, are in a key position to implement strategies to meet the challenges associated with climate change induced coastal vulnerability impacts. For example, adaptation 83

89 strategies could be incorporated into planning schemes, using general coastal management principles such as protection, accommodation, adaptation and retreat. A national audit of local planning schemes would enable assessment of the current state of preparation for climate change at the local level. Locations with a large amount of potentially vulnerable infrastructure and little planning response for climate change issues would be candidates for detailed local study. Moreover, a national audit would enable localities to highlight the resource limitations that in many cases may be limiting their planning. Thus the first-pass vulnerability assessment would serve as a means of identifying priority locations for second-pass study. 6.5 Climate-related thresholds Sea level rise Planning schemes in most Australian local authorities rely upon estimates of the recurrence interval of floods to determine siting regulations for developments: for instance, the 1 in 100 year flood event. Often, a freeboard is imposed above this level, indicating that the floor height of any new construction should be at least above that level. If sea level rise were to occur, this freeboard height may disappear, increasing the risk of unacceptable levels of flooding. This constitutes a climate-related threshold for sealevel rise. Many councils already include an allowance for sea level rise in their planning schemes (e.g. Betts 2001).To assess the prevalence of such thresholds, local planning schemes would need to be collated and compared. Other thresholds could occur for sea defences if sea level rise led to their being overtopped on a much more regular basis than their design threshold. These effects would be highly site-specific. In most locations, an obvious threshold for infrastructure would occur if coastline recession reached the point where it began to undermine the foundations of built infrastructure along the coast. This is already occurring in a number of locations in Australia e.g. Byron Bay, and is the subject of vigorous local debate. In some jurisdictions event based guidelines have been developed; for example, in Western Australia planning may be based on storm surge and wave run-up associated with a design storm occurring concurrently with the mean high water spring tide and the accepted (State) prediction for sea level rise. Increased tropical cyclone winds One important threshold here is the design standard for building construction. If increased tropical cyclone wind speeds caused this to be exceeded, the standard might have to be revised in the future, although this is by no means certain. Another important threshold is posed by the prospect of increased inundation caused by a combination of slightly stronger tropical cyclones and sea level rise. An example has been given for Cairns by McInnes et al. (2003). The effect of this increased occasional inundation would be for more regions of a city to become lower than the 1 in 100 year flood level, a commonly-used threshold for development permission. Increased rainfall intensity Crucial thresholds here include exceedance of design standards for urban stormwater removal infrastructure, and increased riverine flooding, leading to more regions of the city exceeding the planning threshold for flood recurrence. 6.6 Data and research needs There is always a need for improvement in basic climate data and climate change scenarios, but many other studies have detailed these requirements. This section focuses on the specific needs of coastal vulnerability assessment of infrastructure. 84

90 One key data gap is separating the effects of natural erosion, relative sea level rise caused largely by man-made factors, and subsidence. As mentioned in Chapter 2, a key data resource in this effort is aerial photography, which has been undertaken since the 1930s and provides a valuable archive to determine the actual rate of coastal recession. Much of these data are poorly maintained and archived, and a program of recovery and cataloguing is needed. Accurate elevation data appears to be crucial in any assessment of the vulnerability of infrastructure to sea level rise. Such data is not always easy to obtain. A good starting point is a DEM developed by Geoscience Australia, which is accurate to at least 0.3 to 0.5 m for some regions such as South-East Queensland still only marginal for estimating the effects of sea level rise. Even so, not all areas of the coastline are at fine resolution (AGSO, 2001). The national 9 second DEM currently available from AGSO has a vertical resolution of 10 m, completely inadequate for sea level rise studies. Sharples (2004) performed additional analysis to achieve a vertical resolution of 2 m, which is more useful for coastal vulnerability studies, when combined with information on the geomorphic type of the coastline. A technique that offers considerable promise is laser altimetry, which has been employed on the U.S. West Coast to map the height of the coastline to an accuracy of cm, which is adequate for sea level rise studies (Sallenger et al. 1999). Mapping the entire Australian coastline using this technique would cost several million dollars, but results could be obtained in less than a year. Detailed modelling studies to investigate impacts on storm surge and related wave runup levels are also highly dependent on the availability of accurate bathymetric data. An assessment is required to determine the seaward coverage, resolution and accuracy of such data to meet the modelling requirement. The establishment of a catalogue identifying existing coverage held in public and private data-bases would be of value, with priorities for new data collection then to be established. GeoScience Australia has an existing bathymetric gathering program in support of its tsunami risk program. The vulnerability of coastal infrastructure would be determined in large part by the value of that infrastructure. Thus GIS systems incorporating land use and economic value data are needed for vulnerability assessment. A number of such GIS systems have been developed for various locations. Again, Geoscience Australia would be an appropriate starting point for accessing such data. The current vulnerability to tropical cyclone wind damage for engineered structures is well estimated by the Australian Standard for wind loading, which divides Australia into a number of zones depending upon the estimated return period of extreme winds. Increased damage to engineered buildings, from climate change would come not from an increase in winds itself, but from any exceedance of loads in the current design Standard. Thus this would need to be evaluated. The construction of domestic housing and other small buildings should be governed by the Building Code of Australia, which uses the Australian Standard for guidance on wind loads. However, it is by no means clear that the latter is being adhered to, and the vulnerability of these buildings is also affected by local construction practices and inspection procedures. For example, there is strong evidence that the increased wind loads experienced by buildings in exposed topographic situations are not being properly accounted for. To assess properly the vulnerability of coastal infrastructure to wind damage requires detailed surveys of existing building stock, and of significant features such as roof shape, construction materials, and whether fully engineered or not (commercial and industrial buildings are usually fully designed by professional engineers, whereas housing is usually not). Such surveys are required for all communities within about 100 kilometres of the coastline in the tropics. Geoscience Australia is carrying out such surveys, but only for a couple of specific cases (i.e. Cairns, and Innisfail after Cyclone Larry ). After establishing the relevant properties, vulnerability curves (i.e. percentage damage versus gust wind speed) are required to predict damage. Again, Geoscience Australia, with assistance from several other groups, has a programme to achieve this, but with limited funding support. 85

91 6.7 Feasible assessment options First pass vulnerability assessment A collation of coastal aerial photography to establish a time history of coastline position Collection of existing coastal DEM information, including analysis to improve vertical resolution where needed, combined with information on coastal geomorphological types National audit of local coastal planning schemes to determine their level of adaptation to climate change Survey of coastal tropical housing stock, followed by comparison of existing design standards to projected changes in wind speeds National database of storm surge estimates Survey of Stormwater Industry Association members to evaluate current vulnerability of stormwater infrastructure Second pass vulnerability assessment Laser altimetry of coastline, especially areas of high vulnerability identified in the first pass assessment Local studies using GIS coupled with socio-economic data to estimate economic vulnerability to climate change (especially sea level rise) National GIS database of population, housing and infrastructure near the coast. 86

92 CHAPTER 7: Aquaculture and fisheries 7.1 Introduction Australian fisheries (commercial and recreational) target finfish, crustacean, and molluscan species from marine, estuarine, and freshwater habitats. In the value of Australia fisheries production was $2,095 million from a catch of 273 kt. Much of the increase in fisheries production (Figure 8) has been a result of the rapid growth in aquaculture in recent years. This growth is mainly due to developments in Tasmanian salmon production and tuna ranching operations of South Australia (Newton, et al. 2006). Figure 8. Real value of Australian fisheries production and exports. Source: ABARE 2005 For the purposes of this report, commercial and recreational fisheries are referred to as capture fisheries and aquaculture refers to the cultivation of marine (mariculture either offshore or onshore) and freshwater species for the purpose of harvesting for a commercial purpose. Overseas studies have variously shown relationships between near-shore fish stocks or catches and a wide range of climate-related variables: sea surface temperatures, currents, upwelling, downwelling, winds, turbulence, monsoons, rainfall, river flow, salinity and sunshine. Both simultaneous and lagged relationships have been found, and it has been observed that some species vary simultaneously over wide regions. A very useful summary can be found in Balston (In prep.). There are, however, very few assessments of the impact of climate change on either Australian fisheries or aquaculture in the literature. Table 18A, located at the end of the chapter, summarises studies of sensitivity of various Australian species. A report currently with the AGO by CSIRO (Hobday et al, In press) provides a review of the work relating fisheries/aquaculture to climate variability and change, and considers what the impact of climate change may be on these systems. The authors also recommend five possible studies that would provide the industry in general with the greatest immediate understanding of the impact of climate change. These are outside the scope of a first pass vulnerability assessment. This chapter will complement and extend Hobday et al (In press) by: providing details of relevant models, methods and data, detailing the existing vulnerability of the industry providing more information on estuarine, freshwater, and aquaculture systems providing an assessment of the best methods and data to use for a first pass vulnerability assessment. 7.2 Brief review of Fisheries and Aquaculture Sensitivity of Fisheries and Aquaculture to Climate Change A general framework in which to assess the impact of climate change on fisheries is presented in Figure 9. There are many direct and indirect ways by which climate forces affect biological processes in the coastal zone ecosystems. Changes in the processes of the pathways shown over a range of spatial and temporal scales will most likely have a large impact on living marine resources and the economies and communities that depend on them. 87

93 Figure 9 A general framework for assessment of the sensitivity of fisheries to climate variability and change (adapted from Mahon (2002)). Figure 10 summarises species studied in the context of climate variability and the key climate parameters that influence them. These are only a fraction of the species targeted by Australia s fishing industries. Most of the studies dealing with impacts of climate variability on Australian fisheries involve tracking indicators of change, studying cause-effect relationships, and modelling. Details of methods and data are discussed in following sections. The levels of vulnerability in the diagram (Figure 10) are referring to the status of the fishery in terms of fishing sustainability (as explained in detail in the note below the diagram). As shown, there is a wide range of levels depending on the fishery. Most of the fisheries designated over-fished or fully fished have active management programs addressing the situation. These management programs do not incorporate any climate change impacts. Global assessments The sensitivity of fisheries to climate fluctuations has been assessed in many regions of the world. Most of these fisheries operate in nutrient rich areas of eastern ocean boundary currents where the long-term climate signals are easier to identify (e.g. Peruvian fisheries). Useful comparisons between these studies and Australian fisheries are most valuable when considering the impact of climate change on the geographical limits of species distribution. However, due to the uncertainty regarding the mechanisms linking climate and biological systems such transference of results regarding population size is limited. 88

94 Darwin B Leanyer Swamp BP ~ TP S» WP» SS TP Shark Bay WL» W» Exmouth Gulf AS» AH» Perth Species (Vulnerable (V), Not vulnerable (N), Uncertain (U)): Australian herring AH(U) Australian salmon AS(V) Banana prawn BP(U) Barramundi B(V) Brown trout BT(U) Gemfish Eastern G(V) Gemfish Western G(U) Jack mackerel JM(U) King George Whiting K (U) Lobster L(U) Mud crab MC(V) Climate drivers: Penaeid prawns PP(N) Air pressure Pilchards WA P(V) ENSO Pilchards SA P(N) Freshwater flows Saucer scallops S(V)» Leeuwin Current Rainfall School prawn SP(U) Salinity Shark Bay scallops SS(V) Sea level Tiger prawn TP(N) Storms Western rock lobster WL(V) Temperature Whitebait W(U) ~ Wind Western king prawn Shark Bay WP(V) Western king prawn Broome WP(N) Yellowfin Tuna Y (U) AS» AH» Adelaide G ~ Melbourne K ~ Hobart Great Lakes Brisbane Logan R. Dongara Clarence R. Albany P» WA / SA / VIC Herring and Salmon fisheries Gulf of Carpentaria Burdekin R. B Fitzroy R. Hunter R. Sydney BT JM ~ B BP MC Y PP BP SP SP L TAS / VIC / NSW Lobster fisheries Figure 10 A summary of species which previous studies have identified are sensitive to climate variability. Also shown are their main areas of harvest and levels of vulnerability Note: The references for climate sensitivity studies are in Table 18A, located at the end of the chapter and in Appendix C. Definitions: Vulnerable (overfished or fully fished): a depleted fish stock (a biomass below the limit reference limit). Not vulnerable (underfished): a fish stock that has potential to sustain catches higher than those currently taken. Uncertain: a fish stock that might be not overfished, underfished, or subject to overfishing, but for which there is inadequate information to determine its status. (Adapted from Balston 2006). (Source of status information: Table 18 summarises the sensitivity of each of the large-scale systems to climate-drivers and the level of understanding of that sensitivity. The key risks posed by climate impacts for capture fisheries include: Changes to habitat Changes to nutrient supply Changes in productivity, migration, health of these systems and stocks Changes in population sizes, abundance Large and small scale shifts in geographic distribution of species Social & economic risks due to reduced catches and unavailable species. The key risk areas for aquaculture include: Growth Disease resistance, type, and frequency Nutrition issues (appetite, feed efficiency) Water quality/quantity Industry Development: site selection Destruction of cages Effect of climate change on food sources (e.g. pilchards for Southern Bluefin Tuna) 89

95 In summary, there are enough examples of climate-related variability to indicate that fish populations and the fishing sector will be sensitive to climate change. In addition, the current levels of vulnerability (as defined by level of over/under fishing) vary considerably between species, and will influence how vulnerable that particular species is to climate change. Currently however, there is not enough evidence to say conclusively what the impacts of climate change will be for individual species. Table 18 Systems and their Drivers Fisheries Ocean Estuarine River Aquaculture Components that may Productivity, Disease, Productivity, migration, health of these systems and stocks need consideration nutrition Climate-related drivers: sea level L H H H1 sea level- salinity incursions H H near-shore ocean H1-3 depending on circulation patterns species H L L1 wave climate -- waves/ swell/ beach runup M H H M1 storm surge M Coastal wind M1-3 M L M1 hydrological change/ flow L H H Rainfall/runoff/turbidity L H H H2 Tropical Cyclones(and extra-tropical, e.g. east L H H H1 coast lows) water temperature (ocean & fresh) H3 H H H3 Cloudiness and solar radiation, evaporation L M M M1 Air temperature L M M H2 Note: The anticipated impact of changes in the driver on the system is indicated by H, M, L. The level of understanding of the impact the driver has on a system in indicated by 1,2,3 where 1 is high understanding and 3 low. For example, an H3 category indicates a high impact on the system but with a low level of understanding of exactly what that impact will be. 7.3 Assessing potential impacts of climate change on Fisheries and Aquaculture Methods In a review of conference proceedings, Brian Schuter (Aquatic Ecosystems Group, Ontario Ministry of Natural Resources) suggests that there are both direct and indirect methods with which to infer the sensitivity of fish populations to climate over time and space. The direct methods include: assessing direct associations between observed variation over time in climatic and biological variables (e.g. (Staunton-Smith, Robins et al. 2004), assessing direct associations between observed variation over space in climatic and biological variables (e.g. (Young et al. 2001). The indirect methods include: Identifying synchronous biological variability between discrete stocks spread across broad geographic areas that can therefore only be explained by climate variability (e.g. (Klyashtorin 1998), Using a mechanistic model to characterise climate-fish sensitivity in principle. 90

96 The range of models and techniques used for assessing climate sensitivity of species is presented in Table 19. The choice of model or technique is dependent on the type of data available and the knowledge of the species. However, there are few if any Australian studies of the impact of climate change on fisheries. Most assessments of the resource base are focussed on the dynamics of a single species. Important processes that are often not incorporated include spatial dynamics such as oceanographic processes, habitat dynamics, and food chain dynamics. These components are limited by a lack of observational data and poor theory. In terms of specifically addressing the impacts of various climate change scenarios on aquatic resources, methods include: Variations of the historical approach using statistical climate-fish relationships to predict future impacts on the particular population, Uncertainties There is significant debate in the literature regarding the ability of climate parameters to forecast recruitment and other biological measures required for effective fishery management. Much of this is due to the uncertainty regarding the mechanisms linking many physical and biological systems. However, as climatebased forecasts of recruitment appear to be most reliable at the limit of their geographical range, it does suggest that forecasts of recruitment could be essential for assessing the response of the geographical range of species and pest species to global warming. Such models of recruitment are presently available only for a limited number of species. Although it is generally known that aquaculture and mariculture farm productivity is related to climate-dependant processes (such as disease resistance), the quantification of this and the development of appropriate management tools has not yet occurred. The assessment of the vulnerability of aquaculture and mariculture industry development in other locations provides a useful technique to assess the impact on Australian industries, particularly with respect to site selection. However, as different species have different optimal environmental conditions, transfer of results from international regions needs to be done with caution. The mechanistic approach where mechanistic models are used to predict future impacts. Table 19 Models, data, and system knowledge Classes of model and/or system knowledge Fisheries Stock assessment models based on biological processes & including climate parameters. Correlative model between climate and fishery parameters, e.g. Robins et al 2005 Ocean circulation models (larvae dispersal). e.g. Caputi et al 2003 Data required & quality (availability, length) Production (catch) Effort/vessel details, age, recruitment Catch/effort, recruitment Typical scope & scales (temporal & spatial) Single species Localised Single species Multi species Spatial scale limited by processes considered Aquaculture Disease model Disease Species specific Nutrition model Nutrition requirements Site location Utility for climate change work If the model includes climate parameters: high. If not: nil. As above high Deficiencies issues Typical ownership Many do not have climate parameters. Parameter estimation. Nonstationarity. Lack of spatial dynamics. Possible spatial resolution Poor observational data resulting in poor accuracy & precision. Age data is preferred. Poor observati onal data. Data: State or Commonwealth Government depending on who manages the fishery. Data: Research organisation. All approaches are data intensive: they require long-term monitoring programs which, although in place in Australia, are either restricted to a few species (e.g. King George Whiting) or have only been 91

97 implemented in recent years. However, in many cases there is still sufficient information to assess climate sensitivity at some level: such information would include catch data, international studies of same/similar species, or from a conceptual model, for example. In summary, the climate sensitivity of the range of species identified in Figure 10 may well have been determined by a range of techniques depending on the species (e.g. knowledge of life cycle etc) and the data available. A first pass assessment of the impact of climate change will require knowledge of the technique used to assess the specific species climate sensitivity (as further explained in Section 7.4.1) Data required To assess effectively the impact of climate change on fisheries a wide range of data types is required. The data required for much of the modelling in Table 19 are available for only a few species, and collection is usually an expensive long-term exercise. Such data include post-larval data (e.g. Jenkins 2005 collected data from 1993 to 2003), rock lobster puerulus (e.g. Caputti et al 2001 display data from 1969 to 2001), year-class data (e.g. (Staunton-Smith, Robins et al. 2004). Researchers are strongly recommended to examine the report by Bruce, Bradford et al (2002) reviewing the biological and ecological information and data available for the south-east marine region. There appears to be no similar such detailed review for other regions or fisheries. The alternative is to monitor changes in the fishery itself, that is, to use catch and effort statistics. The Fisheries Statistics Working Group (FSWG) that reports to the Standing Committee on Fisheries and Aquaculture, has the mandate of facilitating national fisheries statistics reporting and improving the coordination of fisheries data collection. In most states these catch data are a legislative requirement of all fishery license holders. The information is reported by days (usually averaged into months) across a grid of statistical squares. The length of the catch and effort data is summarised in Table 20. When using these data it is important to be aware of caveats including the use of voluntary logbooks in early datasets and the lack of recorded information regarding vessel and gear details. The problem of scale is particularly relevant in analysing climate related impacts on fish populations (Cushing 1982). Climate change on the scale of five to ten decades or so extends much further than most of the Australian fisheries data which extend to between 20 and 40 years. Fisheries arise and disappear on the scale of many decades primarily owing to changes in the recruitment, changes in the incoming year classes to the stocks. Published papers of Australian climate-fish relationships that have covered long timeframes include: King George whiting (Jenkins 2005), banana prawns (Vance et al 1998), western rock lobster (Caputi et al 2003), spiny lobster and southern blue fin tuna (Harris et al 1988), barramundi, mudcrabs, and prawns (Robins et al 2005). Table 20 Summary of the period and length of State and Federal catch and effort databases Fishery Time period Commonwealth Fisheries/Industry Dates range from starting from 1976 to 1997 running til present. Most start between 1985 and NSW Annual catch summaries 1940 til 1993 Most monthly catch & effort 1984 til present Northern Territory 1993 til present Marine scalefish daily/monthly catch/effort 1976 til present South Australia Inland waters, rock lobster 1983 til present Prawn trawl, scallop, pilchards 1990 til present Aquaculture 1992 til present Tasmania Most from 1985 til present Victoria 1978 til present Aquaculture 1998 til present Western Australia Compulsory logbooks: monthly catch/effort data 1965 til present. Other start dates range from 1962 to1998 Queensland Key fisheries 1988 til present Note: There are data that will fall outside of these summaries. Most, but not all, data are in electronic databases 92

98 7.3.3 Research needs Further research is needed in order to enable mitigation or adaptation of the possible effects of climate change on the fishery sector in Australia. There is presently not enough conclusive evidence of climate change impacts to enable fishery managers to address the issue legislatively. Internationally, the sector is more advanced due to the large amount of research on effects of El Niño and decadal climate oscillations on fisheries environments and resources. Although Australian fisheries lack quantitative predictions of climate change impacts, there is evidence suggesting affects on fisheries could be expected via an intricate set of direct and indirect mechanisms including effects on fisheries habitat, fish populations, their prey, the harvesting sector and fishing communities. General issues to be dealt with in terms of gaps in research, data, and methods include: Long-term monitoring of aquatic biota. Analysis of local, regional, and national changes in the response of the resource to climate change. Analysis of aquaculture sustainability (e.g. changes in culture systems, species, location). Analysis of socio-economic impacts of any changes. Enhancement of funding. Enhanced debate at regional levels. 7.4 Feasible assessment options First pass vulnerability assessment (FPVA) Given the likely time frame of months in which to complete a FPVA, Figure 11 is presented as a possible methodology for analysis of capture fisheries. It is limited to species that already have a climateparameterised model (i.e. mostly those in Figure 10) that can be appropriately adapted to receive climate data from climate change models. Such a model can range from a larvae-dispersal model (e.g. Caputi et al. 2003) which includes boundary wind or current parameters modified for global warming scenarios, or a simple ocean-model that has characteristics known to influence population distribution (e.g. Young et al 2001), to a regression-based model again with suitable climate parameters (e.g. Robins et al 2005). The former technique requires no additional fishery data (e.g. larvae data), while the latter technique can be developed two ways. Firstly, the empirical model can be used as is : that is without any additional fisheries data, simply using climate parameters from climate change scenarios. Secondly, the empirical model can be tested and extended using updated climate and fisheries data, and then for the assessment using the climate change data for the required climate parameter. This second option of testing and further developing the empirical model is clearly the preferred option, however may be limited by unavailable fisheries data depending on what sort of data the model requires. Biological data may well not have been updated, however updated catch data most likely will be available. Nevertheless, the appropriateness of using models based on catch data must be assessed as there are many caveats. 93

99 Figure 11 Possible framework for a first pass vulnerability assessment for capture fisheries (adapted from Robins et al, 2005) Table 18A Studies of the sensitivity of various fisheries species to climate variability or change in Australia Reference (see below) 3, , 17, 22, 26, 27, 31, 33, 34, 35, 38 5, 7,10, 11, 22, 23, 25, , 8, 15 Species Australian Herring Arripis geogianus Australian Salmon Arripis truttaceus Banana prawn Penaeus merguiensis Barramundi Lates calcarifer Brown Trout Salmo trutta trutta Damsel fish Pomacentridae sp. Gemfish Rexea solandri Jack Mackerel Trachurus declivis King George Whiting Sillaginodes punctata Lobster Mud crab Syclla serrata Penaeid prawns Various species Pilchards Sardinops sagax neopilchardus Key Findings Recruitment affected by the strength of the Leeuwin current (SA). Strength of recruitment affected by the strength of the Leeuwin Current (SA). Positive correlation between catch & SOI (NT), rainfall (QLD, GoC), tide levels (GoC), summer flow (GoC), temperature (GoC), winds (GoC). Emigration out of rivers affected by monsoon rainfall (GoC). Temperature and rainfall explain variation in postlarval and juvenile catch (QLD). Recruitment affected by variations in salinity (QLD) & timing, intensity and duration of the monsoon wet season rainfall (NT, GoC) & river flows (QLD). Abundance & growth rates positively correlated with fresh water flow (QLD). Catch affected by flow & rainfall 2 years previous (QLD). Correlation between air temperature and numbers (TAS). Onshore wind & larval supply (GBR QLD) Peaks recruitment match periods of strong zonal westerly winds (TAS). Changes in geographical distribution in response to SSTs, ENSO and Zonal Westerly Winds (TAS). Strength of zonal westerly winds correlated with catch 3 to 5 years later. Significant positive correlation between ENSO and catch at 0 lag (Port Phillip Bay). Significant relationship between TAS, NSW and NZ lobster catch and ZWW, Darwin, Hobart and Macquarie Island atmospheric air pressure. Variation in catch explained by autumn fresh water flow & annual rainfall (QLD). Catch related to temperature of inshore water & rainfall at some previous optimal time lag (QLD). Strength of 2 year old recruits, population structures and production affected by the Leeuwin Current (WA). 94