So what does that mean for future hurricane seasons? Even if storms are becoming more intense, Emanuel points out that more intense storms alone don't necessarily spell big trouble. Devastating hurricanes like Katrina are rare events, he says, because where and when a big storm hits makes all the difference between a devastating big storm and a forgettable one.
For example, everyone will remember Hurricane Katrina for years to come. But hardly anyone probably recalls another Category 4 storm -- Hurricane Brett -- which struck a remote part of Texas in 1999. That storm killed a few cows and quickly left public memory.
"It's like playing the lottery," Emanuel said. "Buying two tickets may double your probability of winning, but you're still talking about a tiny probability that you'll hit all the numbers. It comes down to a roll of the dice."
Give it another 50 years to 100 years, however, and there may be more cause for concern.
"It may be a roll of the dice," Curry said, "but the dice are loaded. And as the oceans keep warming, that's only going to get worse."