Avoiding and Reducing Long-Term Risks of Climate Change. A Technical Report for the Fourth National Climate Assessment

Transcription

1 Avoiding and Reducing Long-Term Risks of Climate Change A Technical Report for the Fourth National Climate Assessment NCAR SDWG Winter Meeting February 28, 2017 Jeremy Martinich Climate Change Division

2 About CIRA and the Technical Report EPA has submitted a draft Technical Report as input to NCA4 This document presents estimates of the physical and economic impacts of climate change in the U.S. across a large number of sectors under two climate change scenarios. The report summarizes results from the second modeling phase of EPA s ongoing Climate Change Impacts and Risk Analysis (CIRA) project, a collaborative effort with a number of modeling teams. CIRA advances the estimation of climate change damages by bridging the gap between climate modeling and economic effects. Consistent socioeconomic and emission/climate scenarios are used to quantify impacts across >20 sectors covering human health, infrastructure, electricity, water resources, agriculture, & ecosystems. The 2017 Technical Report builds off the CIRA framework developed for the 2015 EPA report (Climate Change in the United States: Benefits of Global Action), but has been updated to be consistent with USGCRPrecommended scenarios for use in NCA4. 2

3 About the Technical Report The report includes national and regional summary sections (in both physical and monetary metrics), where results across all sectors are compiled for RCP8.5 and RCP4.5 in 2050 and Adaptation scenarios are also modeled in a number of sectors. The report does not capture all climate impacts on the U.S., and in most sectors, only part of the impact is quantified or monetized. Important sources of uncertainty are discussed throughout. Peer review and transparency: The underlying methodologies have been peer-reviewed and published (with open access) in the scientific literature (several papers are still in review). This documentation of methods and results, including special issues of Climatic Change and Environmental Research Letters, spans more than 35 papers. The report is currently undergoing independent, external peer review to ensure findings are appropriately summarized, accurately described, sufficiently caveated, and clearly communicated. EPA plans to finalize the Technical Report following PR completion. 3

4 About the Technical Report Each sector of the report includes: 2-5 Key Findings Brief background about the impact and sector A summary of the modeling approach, including strengths and limitations, with references to the underlying literature. Results presented in maps, figures, and tables that describe physical and economic impacts across: NCA4 regions Two RCPs and 5 GCMs Two time periods (mid/late century), with some sectors providing more. A discussion that places the findings in context of other research. 4

5 Contributions from Other Agencies This Technical Report benefited from contributions of several agencies: Electric power system modeling with DOE s Pacific Northwest National Lab and the National Renewable Energy Lab. Vectorbornedisease modeling with collaboration from CDC s Office of Infectious Disease. Dynamic vegetation and wildfire modeling with USFS Pacific Northwest Research Station. Heavy reliance on a large number of federal data products, including those produced by NOAA, USGS, USACE, USBR, USFWS, NCAR, NASA, and HHS. 5

6 Summary of Inputs and Assumptions CIRA is designed to quantify the multi-sector impacts of climate change in the U.S. under different global greenhouse gas scenarios (no policy is evaluated). Consistent inputs and assumptions across sectors were chosen to match NCA4 guidelines to the extent practicable: Emissions/Forcing RCP8.5 and RCP4.5 Climate Projections Five GCMs intended to cover range of U.S. temp/precip outcomes LOCA dataset for the contiguous U.S. (same as CSSR) SNAP for Alaska Kopp et al. (2014) SLR scenarios (same CSSR Chapter 12 draft) Population Economic Growth UN 2015 Median Variant scenario (national) downscaled to county level using ICLUSv2 with SSP2 storyline A single GDP projection from the EPPA-6 model driven by the national population projection 6

7 Sectoral Impacts Covered in CIRA2.0 Agriculture Air Quality Roads Aeroallergens Bridges Extreme Temperature Mortality Rail Labor Urban Drainage West Nile Disease Harmful Algal Blooms Domestic Migration Alaska Infrastructure Electricity Demand and Supply Flooding Damages Water Quality Winter Recreation Domestic Yields and Welfare Effects U.S. and Global Agriculture Interactions Coral Reefs Shellfish Freshwater Fish Wildfire Carbon storage Coastal Property Many important impacts are not included in the modeling framework. Future work will expand and deepen the sectors covered. ** internal * deliberative* 7

8 CIRA2.0 Impact Sector Coverage Human health Air quality (ozone only) Aeroallergens (oak only) Thermal stress (mortality only) Labor supply/productivity Vector-borne disease (WNV only) Harmful algal blooms Environmental justice / vulnerable populations Other extreme event morbidity, mortality Agriculture Crop yield (U.S.) Crop yield (global) Carbon storage Specialty crops (U.S. and global) Livestock & dairy production Forests Change in CO 2 storage Wildfire Change in timber production (U.S.) Freshwater Resources Flooding damages Water quality Municipal and industrial supply Groundwater Ecosystems Species-level (coral, freshwater fish, shellfish) Biodiversity, other acidification effects Coastal wetlands Energy Temperature effects on electricity demand/supply Precipitation and system effects on hydro power Change in thermo-cooling capacity Electric power interruptions Climate effects on energy production (non-electric) Infrastructure Non-coastal roads, bridges, and rail Coastal property, including energy infrastructure Alaska infrastructure Urban drainage Coastal energy infrastructure Transportation waterways Water infrastructure (e.g., POTWs) Telecom infrastructure, ROW impacts Tourism Shallow coral reef recreation Recreational fishing Winter recreation Other recreation (e.g., birding) Other Residual damages post extreme events (e.g., hurricanes) Loss of infrastructure use. Catastrophic climate change (e.g., ice sheet collapse) KEY Existing CIRA capacity Partial Not currently in CIRA National security risks (e.g., conflict, mass migration) Violent crime 8

9 Highlights 9

10 Labor Under RCP8.5, labor hours in the U.S. are projected to decrease due to increases in extreme temperatures. Approximately 1.9 billion labor hours are projected to be lost annually by 2090, costing an estimated $160 billion in lost wages. RCP4.5 avoids the loss of more than 900 million labor hours and nearly $75 billion in wages in 2090 compared to RCP8.5. Counties in the South, especially in Texas and Florida, are estimated to lose more than 5% of highrisk labor hours under RCP8.5. Estimated Percent Change in High-Risk Labor Hours in 2050 and 2090 Prepublication Draft See Graff Zivin and Neidell (2014) for details of methodology. 10

11 Extreme Temperature Mortality Changes in extreme temperatures are projected to result in a net increase of approximately 9,300 premature deaths per year under RCP8.5 by 2090 in the 49 modeled cities. Projected Extreme Temperature Mortality in Select Cities Estimated net mortality from extremely hot and cold days. Cities without circles should not be interpreted as having no impact. The projected reduction in deaths from extremely cold days is vastly offset by the projected increase in deaths from extremely hot days in all models, scenarios, and time frames. Compared to RCP8.5, RCP4.5 is projected to result in more than 5,000 fewer deaths each year from extreme temperature in the 49 modeled cities by Inclusion of the entire U.S. population would greatly increase the number of avoided deaths. An optimistic adaptation scenario results in approximately ⅓ to ½ as many deaths across scenarios. Pre-publication Draft See Mills et al. (2014) for details of methodology. 11

12 Alaska Infrastructure Under RCP8.5, cumulative discounted climate-related damages are estimated at $4.5 billion through Under RCP4.5, cumulative damages are reduced to $3.7 billion. The largest damages are projected for the interior and south central regions. Road flooding from increased precipitation is the largest source of damages, followed by damages to buildings (permafrost thaw) Proactive adaptation is projected to dramatically reduce total economic damages. Regional Cumulative Damages to Infrastructure ( , discounted at 3%) Total Damages Per-Capita Damages RCP8.5 RCP4.5 Prepublication Draft See Melvin et al. (2016) for details of methodology. 12

13 Wildfires Contiguous U.S. Under RCP8.5, wildfire acres burned are projected to remain consistent with rates observed over the past several decades, but moderately decrease under RCP4.5, with changes under both scenarios driven by shifts in vegetation over time. Cumulatively through the end of the century, approximately 330 million acres are projected to burn under RCP8.5 and 290 million under RCP4.5. Cumulative, discounted wildfire response costs are estimated at $23 billion through 2099 under both RCPs. Projected Change in Wildfire Activity across the Contiguous U.S. Projected change in average annual acres burned compared to the historic baseline. Results represent average of the five GCMs. Acres burned include all vegetation types and are calculated at a cell resolution of 1/16 th of a degree, converted to ½ degree for mapping purposes. Prepublication Draft See Mills et al. (2014) for details of methodology. 13

14 Wildfires Alaska Wildfire acres burned are projected to increase under both RCPs, especially under RCP8.5. Cumulatively through the end of the century, approximately 120 million acres are projected to burn under RCP8.5 and 98 million under RCP4.5. Cumulative, discounted wildfire response costs (federal only) are estimated at $1.1 billion through 2099 under both RCPs. Projected Impact of Climate Change on Alaska Wildfire Activity Projected change in average annual acres burned compared to the historic baseline. Results are presented at a ½ degree cell resolution RCP8.5 RCP4.5 Prepublication Draft See Melvin et al. (2017) for details of methodology. 14

15 Regional Summaries 15

16 Moving Forward We plan to finalize the Technical Report for use in NCA4, including the chapter entitled Mitigation: Avoiding and Reducing Long-term Risks. This CIRA2.0 modeling effort is intended to serve as a pilot for how coordinated impacts modeling can be used to inform broader science assessments like NCA4. A sustained, coordinated modeling project involving a broader swath of the federal & non-federal climate science enterprise could be initiated with the goal of informing future USGCRP assessments. Develop a sustainable process (akin to EMF) whereby new analyses and modeling can be conducted as the science and policy questions evolve. There s much to leverage and build on given the early successes of BRACE, ACP, and CIRA. 16

17 In case you re interested. Fourth National Climate Assessment Public Webinar for Chapter: Mitigation: Avoiding and Reducing Long-term Risks For AUDIO: Dial , code: Monday March 6 th, 12pm EST

18 Thank You! 18