Dr. Kerry Emanuel explains how Global Warming increased the power of hurricanes. Hurricane Katrina is discussed, with the conclusion that Katrina probably would not have had the power to break the New Orleans levees in a pre-Global Warming world. April 2009 webinar presented by the Southern Allicance for Clean Energy (http://www.cleanenergy.org/) and the Gulf Restoration Network (http://healthygulf.org/) SlideCast by John Atkeison of the Alliance for Affordable Energy. There is a very small amount of phone noise.

1. Hurricanes and Global Warming Kerry Emanuel Massachusetts Institute of Technology

4. The Historical Record

5. Global TC Frequency, 1970-2006 Data Sources: NOAA/TPC and NAVY/JTWC

6. Better Intensity Metric: The Power Dissipation Index A measure of the total frictional dissipation of kinetic energy in the hurricane boundary layer over the lifetime of the storm

7. Atlantic Storm Maximum Power Dissipation (Smoothed with a 1-3-4-3-1 filter) Power Dissipation Index (PDI) Years included: 1870-2006 Data Source: NOAA/TPC

8. Atlantic Sea Surface Temperatures and Storm Max Power Dissipation (Smoothed with a 1-3-4-3-1 filter) Scaled Temperature Power Dissipation Index (PDI) Years included: 1870-2006 Data Sources: NOAA/TPC, UKMO/HADSST1

9. 10-year Running Average of Aug-Oct NH Surface T and MDR SST

11. Tropical Atlantic SST(blue), Global Mean Surface Temperature (red), Aerosol Forcing (aqua) Mann, M. E., and K. A. Emanuel, 2006. Atlantic hurricane trends linked to climate change. EOS, 87, 233-244. Global mean surface temperature Tropical Atlantic sea surface temperature Sulfate aerosol radiative forcing

12. Best Fit Linear Combination of Global Warming and Aerosol Forcing (red) versus Tropical Atlantic SST (blue) Mann, M. E., and K. A. Emanuel, 2006. Atlantic hurricane trends linked to climate change. EOS, 87, 233-244. Tropical Atlantic sea surface temperature Global Surface T + Aerosol Forcing

13. Physics

14. Energy Production: The Hurricane as a Carnot Heat Engine

15. Annual Maximum Potential Intensity (m/s)

16. Observed Tropical Atlantic Potential Intensity Data Sources: NCAR/NCEP re-analysis with pre-1979 bias correction, UKMO/HADSST1 Emanuel, K., J. Climate , 2007

17. Effect of Increased Potential Intensity on Hurricane Katrina

18. Projecting into the Future: Downscaling from Global Climate Models

19. Today’s global climate models are far too coarse to simulate tropical cyclones

21. 200 Synthetic U.S. Landfalling tracks (color coded by Saffir-Simpson Scale)

23. Genesis rates Atlantic Eastern North Pacific Western North Pacific North Indian Ocean Southern Hemisphere Calibrated to Atlantic

24. Seasonal Cycles Atlantic

25. Cumulative Distribution of Storm Lifetime Peak Wind Speed, with Sample of 2946 Synthetic Tracks

26. Captures effects of regional climate phenomena (e.g. ENSO, AMM)

27. Global Percentage of Cat 4 & Cat 5 Storms

28. Now Use Daily Output from IPCC Models to Derive Wind Statistics, Thermodynamic State Needed by Synthetic Track Technique

29. 1. Last 20 years of 20 th century simulations 2. Years 2180-2200 of IPCC Scenario A1b (CO 2 stabilized at 720 ppm) Compare two simulations each from 7 IPCC models:

30. Basin-Wide Percentage Change in Power Dissipation

31. 7 Model Consensus Change in Storm Frequency

32. U.S. Coastal Damage Potential