A number of studies over the past three years have confirmed the relationship between warming surface waters and the intensity of hurricanes:
1) More than 80 percent of the excess heat generated by global warming has been absorbed by the oceans
2) As a result, tropical storms have become 50 percent stronger since the 1970s
3) The proporation of hurricanes that have attained category 5 status has doubled in the last 30 years
4) Global Warming Affects Hurricane Intensity - US Study
5) Man-made factors fuel hurricanes, study finds
6) UK Science Adviser ties Katrina's Intensity to Warming
7) IPCC lead author: "Expect more intense hurricanes"