As this year's hurricane season opens, about the only thing the weather experts can agree on is that Hurricane Katrina was bad. A group of climatologists at Georgia Tech claim that a rise in sea surface temperatures over the last 30 years is "directly linked" to increases in the number of intense hurricanes. Meanwhile, a team at Colorado State University declares "there is no physical basis" for such a connection. "There's a lot of confusion in the field right now," says Chris Landsea, a science officer at the National Hurricane Center who is unaffiliated with either study.
Researchers cannot even agree whether the Katrina season was out of the ordinary. Hugh Willoughby of Florida International University thinks we are primarily seeing the effects of normal climate variations, like El Niño. "The United States had phenomenal luck for the last 30 years, and we got used to it," he says. Greg Holland, a director at the National Center for Atmospheric Research, sees evidence of climate change on top of the natural cycles. In the 1970s, there was a 20 percent chance of the United States' being hit by a hurricane in any given year. Today those odds are more like 35 to 55 percent, he says.
In the short term, 2006 will probably offer little shelter from the storms. At Colorado State, Bill Gray, a leading hurricane forecaster, anticipates a 64 percent chance of a category 4 or 5 hurricane striking the East Coast this year and fifty-fifty odds of another hit in the Texas-Louisiana zone. The real question is, should we be worrying now about the 2036 forecast? Gray suggests we focus instead on bracing for inevitable, routine variations; Holland disagrees. "There is still a large number of scientists—good ones—who don't believe definitely in global warming, so what do they do? They do human nature; they do nothing," Holland says. "But if a foreign country moved all its troops to your border and said there was even only a 20 percent chance of them attacking, would you do nothing?"