1. Climate Change and Water Supply: Potential Hydrologic Consequences Guido Franco Technical Lead for Climate Change Research Public Interest Energy Research (PIER) Program California Energy Commission CALAFCO 2009 Conference October 28, 2009

2. Outline The California Climate Change Center Global and California-specific regional climate scenarios Observed hydrologic trends and projections

3. The California Climate Change Center

4. First state sponsored climate change research program in the nation created in 2003 Virtual research center designed to enhance and complement other state/national/international climate change research efforts Funding: ~ $6 million/year (California Energy Commission) Major research institutions in California are involved: Scripps Institution of Oceanography (UC San Diego), UC Berkeley, LBNL, UC Santa Cruz, Stanford University, etc. Areas of work: –Regional climate monitoring, analysis, and modeling –GHG Inventory Methods –Options to reduce GHG emissions –Impacts and adaptation studies

5. 2006 CAT Report Or 2006 Assessment

6. Global and Regional Climate Scenarios

7. Downscaling the IPCC Global Climate Change Scenarios Statistical Downscaling About 16 global modeling groups in the world

8. Level of Geographical and Temporal Resolution for the CA Scenarios Grid sizes of 7 x 7 miles Daily temperature, precipitation, and river streamflow data

9. Temperatures are going up The historical record indicates that temperatures are going up in CA Agricultural irrigation has “masked” some of the warming SUMMER: Historical Conditions

10. Warming will accelerate in the rest of this century Sample output: GFDL A2

11. Sea Level Rise 2006 Assessment Recent studies suggest a more pronounced increase in sea levels for the rest of this century and beyond 55 inches

12. Hydrological Trends and Projections

13. A drying trend? Most of the global climate models suggest less precipitation in the U.S. Southwest and in California

14. Changes in the timing of streamflows All projections suggest increased streamflows in the winter and less in dry months Average Changes in Monthly Hydrologic Conditions in the Upper American River Project and Big Creek Systems in the San Joaquin River

15. April 1 st Snow Levels

16. Thank you!