ECONOMIC ANALYSIS OF NATURE BASED ADAPTATION TO CLIMATE CHANGE A DASHBOARD APPROACH

Transcription

1 ECONOMIC ANALYSIS OF NATURE BASED ADAPTATION TO CLIMATE CHANGE A DASHBOARD APPROACH DR. GRETCHEN GREENE

2 GRETCHEN GREENE, GREG REUB, FELIX KRISTANOVICH, RAMBOLL ENVIRON; SARAH NEWKIRK AND LILY VERDONNE, TNC; BOB BATTALIO AND ELENA VANDEBROEK, ESAPWA AWRA 2015 SUMMER SPECIALTY CONFERENCE CLIMATE CHANGE ADAPTATION NEW ORLEANS, LOUISIANA JUNE 15, 2015

3 RESEARCH QUESTIONS The Nature Conservancy (TNC) Do Nature Based Adaptation Solutions Pencil? When and Where Do NBA Solutions Work? When and Where Do Structural Solutions Work Better? How Do Ecosystem Services Fit into the Decision Making?

4 PRESENTATION TOPICS Coastal Resilience in Ventura County, California Economics of Adaptation Decisions Ecosystem Services Dashboard of Results Conclusions and Next Steps

5 COASTAL RESILIENCE IN VENTURA COUNTY, CALIFORNIA

6 COASTAL RESILIENCE IN VENTURA COUNTY, CALIFORNIA Coastal communities facing climate change threats must identify cost effective responses to these threats Most responses to climate change induced SLR (sea level rise) focus on defensive engineering or coastal armouring approaches While sometimes necessary, these responses can cause adverse impacts to natural systems TNC developed decision-support network, Coastal Resilience ( to provide tools to better inform stakeholders on climate change and disaster risk reduction, emphasizing the important role of ecosystems

7 COASTAL RESILIENCE IN VENTURA COUNTY COASTAL HAZARD MODELLING Effects of SLR modelled on three planning horizons and three climate change scenarios Coastal Resilience tool considers the following hazards: Coastal erosions, Rising tide inundation zones, Coastal storm flooding, Coastal storm flood combined storm flood hazard zones (waves) BEACH WIDTH ANALYSIS BWA based on hazard modelling Determined changes to beach width under adaptation alternatives Selected to represent broad range of ecological and recreational values and to be representative of Ventura Coastline

8 COASTAL RESILIENCE IN VENTURA COUNTY, CALIFORNIA: INUNDATION MODELLING On-line results available at:

9 COASTAL RESILIENCE IN VENTURA COUNTY, CALIFORNIA Conduct economic analysis of two responses to SLR in Ventura County, CA Response 1: Engineering solutions, Coastal Armouring Adaptation Strategy (CAA) Response 2: Nature Based Adaptation Strategy (NBA) Both responses developed with input from local stakeholders Neither is a pure strategy; each involves some coastal armouring elements, wetland restoration, and natural elements Analyse benefits and costs through time: financial benefits and costs and ecosystem service benefits and costs

10 ECONOMICS OF CLIMATE CHANGE ADAPTATION DECISIONS: NATURE VS. ARMOURING NBA: developed based on feasible engineering options, stakeholder comments, and realistic options Considers restoration of wetlands, dunes, and other natural processes, and managed retreat CAA: developed based on feasible engineering options, stakeholder comments, and realistic implementation options and relative public acceptance Considers construction of sea walls, levees, and other armouring Priority is to protect built property and infrastructure

11 ECONOMICS OF ADAPTATION DECISIONS

12 ECONOMICS OF ADAPTATION DECISIONS Catalyst of Change: SLR & Other Climate Change Adaptation Scenario Buildings and Built Infrastructure Agriculture Ecosystem Services Adaptation Costs Asset Classes Residential Property & Land Values General Building Stock & Land Crop Values & Land Values Benefits from Wetlands Recreation, and Habitat Damages Avoided Net Benefit of Adaptation Scenario Transportation & Public Infrastructure Change in Economic Value Change in Business Interruptions Change in Reduced Agricultural Production Change in Reduced Eco/Beach Tourism Change in Direct Impacts Total Impacts to Regional Economy Economic Impacts: Change in jobs, income, GDP, & taxes

13 ECONOMICS OF CLIMATE CHANGE ADAPTATION DECISIONS DATA Coastal Hazard Data Public Infrastructure Parks and Recreation Parcel Data Replacement Cost of Public Infrastructure Market Value of Residential Homes Recreational use data Agricultural Value Recreational Value Agricultural Crop Acreage Road Value SOURCE ESA PWA Hazus Multiple public sources Ventra County Assessor s Office Hazus DataQuick via LA Times Multiple Public sources Ventura County Agricultural Commissioner's Office USFS Database Ventura County Agricultural Commissioner's Office State of California Flood Rapid Assessment Model (F-RAM) Development

14 ECONOMICS OF CLIMATE CHANGE ADAPTATION DECISIONS Asset Class Basic Units # of Units Value (Millions) Private Parcels with structures 30,151 $15,751.2 Asset Class Basic Units # of Units Value (Millions) Private Parcels with structures 30,151 $15,751.2 Public Parcels 92 $918.8 Public Parcels 92 $918.8 Ag Parcels 408 $936.5 Ag Parcels 408 $936.5 Recreational Parcels 236 $115.8 Roads Miles impacted under current conditions 234 $12.7 Recreational Parcels 236 $115.8 Totals 31,121 $17,735 Roads Miles impacted under current conditions 234 $12.7 Totals 31,121 $17,735

15 ECONOMICS OF CLIMATE CHANGE ADAPTATION DECISIONS Hazard Description Variable Measurement Economic Damage Function Used Extreme Monthly High Water EMHW, a high tidal water level reached approximately once per month. This represents areas that are regularly flooded by ocean tides. Depth of flood used to estimate baseline. USACE Depth Damage Functions based on number of stories, presence of basement, and depth of water measured in feet. Flood depth of major coastal storms This flood depth is based on a record storm in January Flood depths are only included for areas outside the wave hazard zone. Mean flood depth of major coastal storm within parcel measured in Meters USACE Depth Damage Functions based on number of stories, presence of basement, and depth of water measured in feet Wave Zone Area Parcel is located in a wave zone area., dominates flood inundation Presence of wave hazard in any part of parcel (YES/NO) Loss of value based on USACE functions. Long Term Erosion Area of long-term, continued erosion due to SLR. Percent of parcel in long-term erosion hazard zone (%) < 50% erosion = 50% loss in value, > 50% erosion = 100% loss in value

16 INCORPORATING ECOSYSTEM SERVICES

17 INCORPORATING ECOSYSTEM SERVICES NESA (Net Ecosystem Services Analysis) Calculate net benefits/declines in services from the environment to humans HEA (Habitat Equivalency Analysis) applied to results from SLAMM to evaluate changes in ecosystem services by land cover type HEA converts estimates into SAY ecosystem services provided by one acre of saltwater wetland for one year These results can be discounted or turned into net gain or loss as per BCA HEA Environmental Annuities Model requiring: Area disturbed/lost/restored/gained Habitat types Relative habitat quality over time Time frame of project impacts and benefits

18 INCORPORATING ECOSYSTEM SERVICES Assume level of ecosystem services is proportional to habitat quality Important to determine slope and shape of ecosystem service recovery curves Also must determine the social discount rate for estimating social value of future natural resource services HEA uses input data from SLAMM (Sea Level Affecting Marshes Model) Scale land cover types to compare highest value land type for ecosystem services, compared to saltwater/estuarine wetlands SLAMM Simulates dominant processes involved in wetland conversions during long term SLR, including inundation, erosion, overwash, saturation, and accretion Input: High-res digital elevation model, map of wetland habitats, future SLR projections, marsh accretion rates, tide ranges, and erosion rates.

19 INCORPORATING ECOSYSTEM SERVICES NESA (Net Ecosystem Services Analysis) Calculate net benefits/declines in services from the environment to humans HEA (Habitat Equivalency Analysis) applied to results from SLAMM to evaluate changes in ecosystem services by land cover type HEA converts estimates into SAY ecosystem services provided by one acre of saltwater wetland for one year These results can be discounted or turned into net gain or loss as per BCA

20 DASHBOARD RESULTS

21 DASHBOARD RESULTS Two Questions: Do the benefits exceed the costs for the adaptation strategy? Which strategy produces the greatest net benefits? Allows decision makers to explore how decision outcomes change over a variety of assumptions: Frequency of Storm Value of Ecosystem Services Discount Rate

22 DASHBOARD RESULTS CAA and NBA yield greater benefits than costs in terms of mitigation SLR damages as compared to the baseline Assuming 3% discount rate and storm incidence of 1% a year, NBA reduces damages by 66% and CAA by 76% NBA produces 44,000 SAY additional of ecosystem services

23 DASHBOARD RESULTS Costs and Benefits in Millions $2,000 $1,500 $1,000 $500 $0 NBA CAA Damage Reduction and Recreation Costs Costs and Benefits in Millions $2,000 $1,500 $1,000 $500 $0 NBA CAA Damage Reduction and Recreation Costs Costs and Benefits in Millions $2,000 $1,500 $1,000 $500 $0 NBA CAA Damage Reduction and Recreation Costs Net Benefits in Millions $800 $600 $400 $200 $0 NBA CAA Net Benefit Ecosystem Service Value Net Benefits in Millions $300 $200 $100 $0 Net Benefit NBA CAA Ecosystem Service Value Net Benefits in Millions $150 $100 $50 $0 -$50 -$100 -$150 NBA CAA Net Benefit Ecosystem Service Value 50 Year Event 100 Year Event 200 Year Event

24 DASHBOARD RESULTS Net benefits (benefits minus costs) increase as the discount rate decreases Net benefits increase as the frequency increases The NBA solution is more favourable than the CAA solution as the monetary value of one acre of saltwater wetlands increases In the face of uncertainty, we do not need to know what will happen we need to know the tipping points where our decision would change

25 CONCLUSIONS AND NEXT STEPS

26 CONCLUSIONS Suggest nature based approaches to climate change adaptation can provide benefits Can reduce damages comparable to coastal armouring/engineering approaches Value of saltwater wetlands and other ecosystem services (e.g. recreation and agriculture) interacts with benefits and costs Decision makers can use dashboard results to inform decisions about climate change adaptation choices Allows for exploration of which alternatives perform best across a variety of assumptions Easily customizable dashboard for decisions makers to choose priorities Stakeholder input is critical Interdisciplinary collaboration is key

27 NEXT STEPS Working to add some of the benefit cost work into on-line application for Coastal Resilience Ventura Site-specific decision making can build from existing effort Need to include more formal probabilistic estimates of benefits and costs Need to include more emergency, relocation, and other costs Ecosystem services analysis needs formal HEA

28 THANK YOU CONTACT GRETCHEN GREENE OR GREG REUB RAMBOLL ENVIRON