Two US studies have reported new evidence supporting claims that global warming is causing stronger hurricanes. But neither the authors nor other experts say the claims are conclusive.

In the first study, Matthew Huber of the US's Purdue University's department of earth and atmospheric sciences along with his colleagues calculated the total damage that could be caused by storms worldwide, using data normally applied to reconciling weather forecast models with observed weather events. He found that their results matched an earlier work by Kerry Emanuel, of MIT, USA. Emanuel argued that global warming strengthens hurricanes.

In another study, Emanuel and Michael Mann, a meteorologist at the Pennsylvania State University, USA, compared global sea surface temperatures with those of the tropical Atlantic, saying stronger hurricanes were caused by rising ocean surface temperatures. Some experts say secular weather cycles, not global warming, cause stronger hurricanes, which Emanuel and Mann reject.