Is There A Link Between Hurricanes and Global Warming?

"There's no question it's been a schizophrenic season," said Chris Mooney, author of the book Storm World, which explores the link between global warming and hurricanes.

With its Category 5 storms and low ACE index, the 2007 season offers ammunition for both camps of scientists arguing over the impact of global warming on hurricanes.

The overall number of systems for this year so far — 14 named storms, four of which became hurricanes — is above the long-term average of about 10 named storms a year.

But scientists who believe global warming is having a measurable effect on hurricanes say climate change is more apt to influence the intensity of systems, rather than the overall number.

"Two Category 5s in a slow year argues in favor of the climate change hypothesis, as the per-storm intensification rate was quite high this year," said James Elsner, a Florida State University hurricane scientist who believes global warming is affecting storm activity.

Yet some hurricane scientists who are uncertain whether hurricane activity would already be showing a measurable effect from global warming say having two Category 5 hurricanes in a single season may not be much of a rarity in the Atlantic.