1. Pacific Northwest Climate Model Scenarios 2008 Climate Impacts Group & Department of Atmospheric Sciences University of Washington Eric Salathé Philip Mote Valérie Dulière Emily Jump

2. Are Humans Responsible?

3. IPCC - WGI Are Humans Responsible?

4. IPCC (1995): “Balance of evidence suggests discernible human influence” IPCC (2001): “Most of warming of past 50 years likely (odds 2 out of 3) due to human activities” IPCC (2007): “Most of warming of past 50 years very likely (odds 9 out of 10) due to greenhouse gases” Are Humans Responsible?

5. 20th century seasonal cycle in PNW

6. Annual mean, minus NCEP

7. 20th century trend

8. PNW Temperature Change 10°F 0°F

9. 2040s - 1980s PNW

10. Projected Temperature temperature2020s2040s (°C)oldnewoldnew lowest0.40.60.80.9 average1.11.2*1.62.0* highest1.81.92.62.9 *weighted average

11. Projected Precipitation precipitation2020s2040s %oldnewoldnew lowest-4-9-4-11 average21*22* highest6129 *weighted average

12. IPSL ECHAM5 SRES A1BSRES B1 CCSM3 Percentages of change in the annual maximum daily precipitation with a 10 years return period for each PNW grid cell between 1981-2000 and 2046-2065. +12.2% +18.8% +11.4% +10.8% +11.8% +10.6% changes in extreme daily precipitation

13. Downscaling global models for regional studies

14. Downscaling -- Winter

15. Downscaling -- Summer

16. Mesoscale Climate Model  Based on Regional Weather Model (MM5, WRF)  Nested grids 135-45-15 km  Advanced land-surface model (NOAH)  Forced by Global Climate Model output (boundary conditions)

19. Regional questions Snow/moisture/cloud interactions Extreme precipitation Heat waves Wind storms

20. Summary Temp and precip: central values roughly the same as 2005 estimates, 0.5°F/decade warming and little change in annual total precip Increased likelihood of drier summers, wetter winters, heavy rains Coming soon: much more detailed scenarios

21. sea level pressure (NCEP, CGCM3.1)

22. Model Performance observed

23. Ranked Model Performance

24. Scenario Selection - T/P Scatter

25. Future Storm Track Changes North America Asia Europe NP Stronger N Atlantic Storm track Stronger N Pacific Storm track ULBRICH ET AL. 2008 Change from 1960-2000 to 2080-2100 Composite of 16 Global Climate Models

26. Future global climate IPCC Fourth Assessment Global