Climate Change Fuels Debate over Hurricane Threat

Members of the American Meteorological Society are meeting in New Orleans. There is a debate over whether warmer water, caused by climate change, will cause more destructive hurricanes like Katrina.



The monster hurricane has come to illustrate climate change for the public, but not for weather experts. There is no scientific consensus on whether a warmer world will mean a lot more destruction from storms like Hurricane Katrina. Actually, there is so much disagreement that a scientific debate can turn into an intellectual smackdown. That's just what happened last night at the American Meteorological Society meeting in New Orleans.

NPR's Jon Hamilton had a ringside seat.

JON HAMILTON: Hurricane science can be pretty hard to follow, even up close. Here's Greg Holland of the National Center for Atmospheric Research.

Dr. GREG HOLLAND (National Center for Atmospheric Research): The second you go down to the bottom, the standard parameters are vorticity ten to the minus five, relative humidity 50 percent...

HAMILTON: But it's easy to tell when scientists disagree. Here's Holland in an exchange with Christopher Landsea of the National Oceanic and Atmospheric Administration.

Dr. CHRISTOPHER LANDSEA (National Oceanic and Atmospheric Administration): Can you answer the question?

(Soundbite of laughter)

Dr. HOLLAND: I'm not going to answer the question because it's a stupid question.

Unidentified Man: Okay. Let's move on.

(Soundbite of laughter)

HAMILTON: Holland and Landsea represent the extremes in the debate about global warming and hurricanes. Holland thinks it will have a big effect. Hurricanes are powered by warm water, after all. Landsea thinks the effect will be small because it takes a lot more than warm water to make a hurricane.

Each uses the historical record to support his position. Holland uses it to show a rise in the number of the most powerful hurricanes. Landsea says that apparent rise is probably because the historical record is faulty. Before satellites, a lot of storms at sea probably went undetected. And even a few decades ago, storms like Hurricane Wilma in 2005 probably would have been underestimated.

Dr. LANDSEA: If Wilma happened in 1950, 1955, '45, we wouldn't know it was a Cat 5. We wouldn't know was the strongest hurricane on record.

HAMILTON: Landsea and Holland were among a half-dozen scientists who took part in a debate about climate change and hurricanes.

Early on the scientists pummeled each other with claims and counter-claims involving data sets and computer models. But then late in the afternoon the discussion changed.

Kerry Emanuel from MIT described his work linking climate change to the total energy produced by hurricanes. Then he reminded his colleagues that they were in New Orleans.

Professor KERRY EMANUEL (MIT): All this debate we're having up here is a little irrelevant for practical, you know, coastal concerns, unless you're worried about 200 years from now, maybe. What people want to know is whether they're going to get clobbered.

HAMILTON: Johnny Chan from the University of Hong Kong added that many governments outside the U.S. need to know now whether they should start planning for extreme weather.

Professor JOHNNY CHAN (City University of Hong Kong): We as scientists are actually responsible for helping the governments to answer that question. We might not be able to answer it perfectly right now, and that's why we're doing all this, is to try to answer - at least provide some guidance.

HAMILTON: By the end of the session, panelists were emphasizing things they could agree on.

Thomas Knutson of the National Oceanic and Atmospheric Administration acknowledged the scientific uncertainty about how much climate change will affect hurricanes. But he said even a small effect could eventually cause big problems.

Mr. THOMAS KNUTSON (National Oceanic and Atmospheric Administration): We may not experience it ourselves in our lifetime, but our grandchildren and such would. And I think that we owe it to the future generations to understand as best we can what we're doing to the planet, particularly things which may be quite damaging.

HAMILTON: Like a Category 5 hurricane.

Jon Hamilton, NPR News, New Orleans.




