Climate scientist Kerry Emanuel knows hurricanes, and has historically been extremely cautious about drawing connections between global warming and hurricane strength or frequency. So when he published an article this past summer in Nature arguing a strong connection between climate change-driven ocean warming and hurricane intensity, the scientific world took notice. And when hurricane Katrina hit the Gulf Coast a couple of weeks later, lots of other people took notice, too.
Today's New York Times has a brief profile and interview with Dr. Emanuel, one that helps to underscore the shift he has made from caution to concern.
There is no doubt that in the last 20 years, the earth has been warming up. And it's warming up much too fast to ascribe to any natural process we know about.
We still don't have a good grasp of how clouds and water vapor, the two big feedbacks in the climate system, will respond to global warming. What we are seeing is a modest increase in the intensity of hurricanes.
I predicted years ago that if you warmed the tropical oceans by a degree Centigrade, you should see something on the order of a 5 percent increase in the wind speed during hurricanes. We've seen a larger increase, more like 10 percent, for an ocean temperature increase of only one-half degree Centigrade.
Katrina was just the beginning.