Humans and hurricanes

Don't blame Mother Nature's wrath over global warming for the incredible devastation wrought by recent hurricanes (damage from Katrina is already expected to reach $25 billion). MIT global warming expert Kerry Emanuel tells Salon that humans share a big part of the blame:

The recent hurricanes in the Atlantic, Emanuel explained, represent a natural fluctuation. Every 20 to 30 years, since records started being kept in the 19th century, there have been big shifts in the frequency of hurricanes in the Atlantic. "For example, in the 1940s and '50s, there were very busy years, whereas the 1970s and '80s were very quiet years," he said. "And we've had a big upswing in the Atlantic beginning in about 1995. That's all natural."

The reason violent Atlantic hurricanes like Katrina may strike people as unnatural, and cause them to blame the CO₂ pouring out of their neighbors' Hummers, is not because of their frequency but their destruction to people and places.

"This natural fluctuation occurs in a social environment where there is a huge shift in demographic trends, and this makes a big difference in people's perception," Emanuel said. "In the 1940s and '50s, there were lots of hurricanes in Florida, but there weren't lots of people there. So now that we're having this upswing again, it's being perceived very differently" -- for the simple fact that there is a lot more stuff to be ruined.

... Ultimately, Emanuel said, it's not a vengeful Mother Nature but man's politics that are to blame for the destruction. As long as people insist on erecting homes and businesses, aided by low insurance rates and business lobbyists, in vulnerable areas like the Gulf Coast, there's little scientists can do to prevent the havoc. "I like to say that there is no such thing as a 100 percent natural disaster," Emanuel said. "We have to put stuff in harm's way for there to be a disaster, and we're very good at doing that, and subsidizing people who continue to do it."