The scientific basis for natural capital: developing metrics for a risk register. Georgina Mace University College London

Transcription

1 The scientific basis for natural capital: developing metrics for a risk register Georgina Mace University College London

2 Outline 1. Natural capital status and trends 2. Developing a risk register for natural capital 3. Ecological thresholds, targets and risks 4. Results from a preliminary analysis

3 What is natural capital? One type of capital on which people ultimately depend (i) produced or manufactured capital (roads, buildings, machines) (ii) human capital (health, knowledge, culture and institutions), (iii) natural capital (available from nature).

4 1. NATURAL CAPITAL: STATUS AND TRENDS

5 Human activity has already radically altered natural ecosystems More than two thirds of the area of two global biomes and more than half of the area of four others had been converted by 1990

6 Human activity has already increased species extinction rates to about 100x pre-historical level Up to one third of species in some fully-assessed groups are now listed at risk of extinction, more than 10% in all groups comprehensively assessed. Published by AAAS M Hoffmann et al. Science 2010;330:

7 The status of threatened species is deteriorating. Published by AAAS M Hoffmann et al. Science 2010;330:

8 Local abundance of species groups has declined up to ~50% since 1970 Living planet index Wild bird index Waterbird population Pereira HM 2012

9 The impacts of people on ecosystems are already widespread and intense (HANPP) Human appropriation of net primary productivity c. yr 2000 (Haberl et al. 2007, PNAS)

10 Global Human Appropriation of Net Primary Productivity (HANPP) growing throughout the last century. Development of global HANPP by major land use type and human induced fires HANPP intensity measured as HANPP per capita, HANPP per unit of GDP and total HANPP per unit of biomass harvest declined, indicating increasing land use efficiency by National Academy of Sciences Krausmann F et al. PNAS 2013;110:

11 Growth in population and human activities by The Royal Society Steffen W et al. Phil. Trans. R. Soc. A 2011;369:

12 Are we are reaching environmental limits? WWF Living Planet Report 2006 Rockström et al 2009 Nature 461,

13 E.S. Process Control Variable Boundary State of Knowledge Climate change CO2 conc 350 ppm Good, but debate on energy change +1 W m2 boundary position Ocean acidif. arag. sat ratio 20% reduction Process understood Stratospheric O3 conc, DU 5% reduction Boundary agreed O3 loss from pre-indust and respected Atmos aerosols part. conc. TBD Thresholds unknown P & N cycles N: amt fixed 35 Tg N/yr Boundaries are P: inflow to ocean 10 x pre-indust educated guesses Freshwater use Blue water use 4000 km3/yr Global aggregate Land system Fraction of land 15% ice-free Regional distribution change cultivated land surface is critical Biodiversity Extinction rate <10 E/MSY Diversity-functioning?? Chem. Pollution Amt emitted TBD Aggregate effects??

14 What is the right amount/status/condition for natural capital? Already radically altered by people, so history is informative but not a basis for policy. Future demands/needs will be greater and different to now. Life itself will probably be fine. The primary responsibility is to people, especially to address hunger, disease, suffering and inequity, now and in future. The priority is to sustain a habitable and resilient environment for people.

15 Predictability of contribution to safe operating space Three proposals for planetary boundaries for biodiversity low Genetic library of life Biome resilience Functional traits in ecosystems high Mace, Reyers et al, in review 2013 Years in future

16 2. CONCEPTUAL BASIS FOR A RISK REGISTER FOR NATURAL CAPITAL

17 Towards a risk register for natural capital The work of the NCC To be published with the NCC s 2nd State of Natural Capital Report, March 11 th 2014.

18 Natural capital is a stock on which people depend for wellbeing, but which we do not have to create or manufacture There are many kinds of natural capital and classifications: e.g. Living non living Renewable non renewable Substitutable non substitutable Replaceable non replaceable Here the question is what is at risk from its loss/degradation? How does natural capital support wellbeing?

19 BIODIVERSITY ECOSYSTEMS, ECOSYSTEM SERVICES NATURAL CAPITAL Biodiversity describes the diversity of life. It is one component of ecosystems, but the abiotic components of ecosystems are also important for ecosystem services Ecosystem services rely on biodiversity, but biodiversity may also be an ecosystem service. Natural capital includes the stock of all natural components and is therefore a more inclusive term than both biodiversity and ecosystems, and supports a wider set of benefits than ecosystem services.

20 Services Goods Benefits (Values) Other capital inputs Natural Capital Assets Management Inputs

21 Creating a risk register for natural capital: Risk = f (hazard, exposure) Here : - hazard is measured as the extent of degradation of natural capital - exposure is measured as the potential loss of benefits We aim to highlight the most serious risks.

22 As the natural asset status deteriorates, the benefits may reduce, potentially below critical levels Required level of benefit Anthropogenic pressures

23 This seems simple in principle, but many details have to be resolved What are the assets? What are the benefits? What are the relationships between asset status and benefits? What are the targets for each benefit? Where and what are the thresholds?

24 What are the natural capital assets? The classification needs to reflect major classes of natural capital assets, delivering major categories of benefits: Species (incl. genetic variation), Ecological communities, Soils, Freshwaters, Land, Minerals, Atmosphere, Subsoil assets, Oceans, as well as the natural processes and functions that they depend upon

25 Is all natural capital included in the risk register? Some elements of natural capital are not subject to anthropogenic influence (whether intended or not), and so are excluded. Include only assets that are: Changing or likely to change in measurable levels over policy-relevant timescales (decades); Have some actual or potential relevance to human welfare, now or in the future; and Be plausibly subject to management by people.

26 What are the benefits? Food Fibre (timber) Energy Fresh water (quantity) Fresh water (quality) Recreation Clean air Amenity Aesthetic Wildlife conservation Equable climate

27 What are the relationships between asset status and benefits (1)? Natural Asset Land maintained as woodland/trees Benefit Equable climate (carbon storage) Relationships 1. Primary influence of area=biomass 2. Secondary influence of species composition/ species diversity 3. Marginal influence of location/fragmentation

28 Relationships for the benefit of climate regulation (carbon storage) b=~0.5 Ruiz-Jean & Potvin, New Phyt Hulvey et al 2013; Nature Climate Change

29 What are the relationships between asset status and benefits (2)? Natural Asset Land area Benefit Wildlife Relationships 1. Influence of area (SAR) 2. Influence of quality (disturbance and type) 3. Influence of patchiness/fragmentation

30 Relationships for benefit of wildlife (species richness)

31 Linking benefits to assets is very difficult.. Complicated by context-dependency, shifting dynamics, interconnectedness etc. Many asset benefit relationships vary with the landscape/seascape type and with land use. Information is organised by land use type or habitat type much more often than by asset. Management tends to be aligned with land uses more than with aggregates of assets. So we do the assessment using land use types as accounting units

32 UK NEA Broad Habitats (ecosystems) Freshwaters - Openwaters, Wetlands and Floodplains Urban Marine Coastal Margins Mountains, moors and heathlands Semi-natural grasslands Enclosed farmland Woodlands 32

33 Distribution of UK habitats

34 Major land-use types (NEA Broad Habitat Types) Ecosystem Services Goods Benefits (Values) The risk register lists major risks to benefits from natural capital through the lens of the major land use types Natural Capital Assets Species Ecological communities Soils Freshwaters, Land Minerals Atmosphere, Subsoil assets, Oceans, Natural processes & functions Management Inputs Other capital inputs

35 Determining the relationships between benefits and natural assets in land use classes Consider three kinds of relationships for each land use class and benefit: Quantity (area) Quality (condition, other attributes, management) Spatial configuration (location, fragmentation, connectedness) Reflect ecological thresholds as far as is possible/relevant Recognise uncertainty in science and evidence Best estimates based on available evidence and expert opinion

36 Low risk or High risk change in benefits Required level of benefit Anthropogenic pressures

37 3. THRESHOLDS AND RISKS

38 Risks and thresholds What is high versus low risk? - Declining status and below target is very high risk - Declining rapidly or below target is high risk - At or above target, increasing or stable is low risk How does risk relate to thresholds?

39 Ecological thresholds: The point at which a non-linear or substantive change in the dynamics or distribution of an organism, population or community is observed, relative to some level of disturbance. (a.) defined by population dynamics, e.g. regulation and limitation. A hysteresis effect is possible. (b.) where the threshold is defined simply by the population trajectory (nonlinear) and specific levels of habitat conversion. Johnson, C.N. Biodiversity Conservation 2013

40 Regulatory limit c, a regulatory limit restricts habitat loss, based on habitat loss is restricted to 30% of the landscape. There is uncertainty about the limit, in practice about the relationship between population number and habitat (shaded zones and dotted lines), with a greater level of uncertainty for an unobserved, but plausible nonlinear response. Johnson, C.N. Biodiversity Conservation 2013

41 For the risk register.. Ecological thresholds are very poorly understood and have high context-dependency Ecological thresholds do not relate clearly to benefits, and may often be encountered after benefits are reduced Rather than use poorly known and/or subjective thresholds, or weak proxy metrics, we chose to use targets established at regional and national level. Ideally, metrics would be chosen to best resolve the relationships

42 Existing targets EU Water Framework Directive EU Birds and Habitats Directives SSSI EU Bathing Waters Directives Government woodland cover target Government Climate Change Committee targets Air quality standards Current stock levels (fisheries)

43 4. PRELIMINARY RESULTS TOWARDS A NATIONAL RISK REGISTER

44

45 Estimates of the financial benefits of restoration to target level

46 Summary and conclusions People depend on natural capital; natural capital is by and for people, not for nature itself. Metrics and assessments of natural capital show accelerating rates of loss to date, and no reason to think this will slow in future. For current and future generations, natural capital measurement and monitoring will allow decisions about what level of degradation is unsustainable, what can be foregone and what is irreplaceable. The work on metrics and the risk register identifies some major gaps in knowledge and understanding that need to be filled if those decisions are to be made with a reliable evidence base Generalisable ecological thresholds Relationships between natural capital assets and benefits Natural capital assets versus land use categories

47 Many thanks to: The Natural Capital Committee (especially Rosie Hails) The NCC Secretariat in Defra (especially Julian Harlow and Stewart Clarke) Eftec, Cascade Consulting and NERC CEH