1. Climate change impacts on water resources in the southeastern U.S. – Can we adapt? Peter Caldwell USDA Forest Service, Eastern Forest Environmental Threat Assessment Center Raleigh, NC SWPBA Annual Meeting, November 2011

2. Climate change- The scientific basis IPCC AR4, 2007

3. Unprecedented rate of change IPCC AR4, 2007

4. The evidence of change IPCC AR4, 2007 Temperature Sea level Snow cover

5. IPCC AR4, 2007 “Global warming is unequivocal and primarily human-induced” USGCRP, 2009

6. Change Variability Variability v. Change Bottom of Hill (current climate) ‏

7. USGCRP Global Climate Change Impacts in the United States, 2009 Precipitation

8. USGCRP Global Climate Change Impacts in the United States, 2009 Temperature

9. Extremes: Drought USGCRP, 2009

10. Extremes: Heavy precipitation USGCRP, 2009

11. Global Circulation Models Coupled land & atmosphere models Global coverage Coarse resolution (e.g. 2° - ~100x100 km) Have Biases Spatial resolution Model parameterization Scale not appropriate for impact studies

12. Bias correction and downscaling Maurer, 2009 2° resolution (100x100 km) 1/8° resolution (12x12 km) Dynamic or statistical downscaling

13. Emission scenarios IPCC AR4, 2007

14. Predicted global temperature IPCC AR4, 2007

15. Temperature changes IPCC AR4, 2007 A1B Scenario, change in temp from 1900- 1950 mean, multi-model mean and range A1B Scenario, change in temperature from 1980-1999 by 2080-2099, multi-model mean

16. Precipitation changes Annual precipitation change Number of models predicting increased precipitation IPCC AR4, 2007 A1B Scenario, change in precipitation from 1980-1999 by 2090-2099, multi-model mean

17. Key Issues for the Southeast Heat-related stresses for people, plants, and animals Decreased water availability Sea-level rise, likely increase in hurricane intensity and storm surge Ecological thresholds likely to be crossed throughout the region USGCRP, 2009

18. US Forest Service: A Legacy Water Resources Management Organic Act of 1897 “…securing favorable conditions of water flows…” Weeks Law of 1911 “…..regulation of the flow of navigable streams or for the production of timber.” Sustained Yield Forest Management Act of 1944 “….. maintenance of water supply, regulation of stream flow, prevention of soil erosion, amelioration of climate, and preservation of wildlife.” National Forest Management Act of 1976 “…multiple use and sustained yield of the products and services obtained…the coordination of outdoor recreation, range, timber, watershed, wildlife and fish, and wilderness.”

19. The future of USFS water resources management

20. SupplyDemand Climate Landuse change Population Reservoir GW Infrastructure Economics J. Am. Water Resour. Assoc. 44:1441 – 1457, 2008 Water Supply Stress Index (WaSSI) Model

21. Water Balance ET = f(PET, LAI, PPT, SM) Q = PPT – ET +/-  S Carbon Balance GEP = f(ET) Re = f(GEP) NEE = Re - GEP Biodiversity BIO = f(ET) -Birds-Amphibians -Reptiles-Trees -Mammals-Vertebrates PPT ET Q GEP Re Watershed and Land Cover Based

22. Climate and Population Scenarios Baseline (2001-2010) vs. Future (2051-2060) Climate ScenarioPrecipitationPET CSIROMK2-B214% CSIROMK3.5-A1B5%11% HADCM3-B27%15% MIROC32-A1B8%19%

23. Simulated 2001-2010 water yield

24. Predicted trend in water yield

25. Predicted trend in water yield 2011-2060

26. Simulated 2001-2010 streamflow

27. Predicted change in flow by 2051-2060

28. Change in water demand by 2051-2060

29. Water Supply Stress Index (WaSSI) Water Stress: Average annual WaSSI ≥ 0.4 United Nations (Raskin et al., 1997) World Water Council (Alcamo, 2000; Cosgrove & Rijsberman, 2000) Vörösmarty et al., 2000 WaSSI = Demand Surface + Groundwater Supply

30. Mean WaSSI in 2051-2060

31. Predicted trend in mean annual stream temperature 2010-2060, mean among four scenarios Stream temperature changes

32. Sediment delivery changes Predicted change in rainfall erosivity (R) by 2050

33. What can we do? Mitigate Reduce carbon emissions Enhance carbon sequestration Adapt Enhance ecosystem resilience Enhance infrastructure resilience Embrace uncertainty “If mitigation is about carbon, then adaptation will be about water”

34. Peter Caldwell pcaldwell02@fs.fed.us 919.515.1560 www.forestthreats.org Thank you!