http://www.chicagotribune.com/news/chi-oceans_23jan23,0,998942.storyStudy: Global warming may curb growth of hurricanes
South Florida Sun-Sentinel
January 23, 2008
FT. LAUDERDALE - At least as it pertains to hurricanes, it seems global warming might have a positive result..
Two South Florida scientists have found that steadily warming oceans should translate to fewer Atlantic hurricanes striking the United States.
The reason: As sea surface temperatures rise, vertical wind shear increases. And wind shear makes it difficult for storms to grow, which was seen in the past hurricane season, when several systems were stunted.
"Using data extending back to the middle 19th Century, we found a gentle decrease in the trend of U.S. landfalling hurricanes when the global ocean is warmed up," said Chunzai Wang, an oceanographer with the National Oceanic and Atmospheric Administration.
Sang-Ki Lee, a marine and atmospheric researcher at the University of Miami, worked with Wang on the study. Their findings are to be published Wednesday in Geophysical Research Letters.
Wang and Lee's conclusions contradict several other studies, which hold that global warming is increasing the intensity, duration and number of tropical systems.
But their study isn't the first to say warmer oceans increase wind shear. Last April, another NOAA-backed study found an increase in greenhouse gases and warmer oceans also does so.
The Wang-Lee study, however, is the first to assert the increased wind shear should result in fewer hurricanes striking the U.S. coastline.
http://www.chicagotribune.com/news/nationworld/sns-ap-hurricanes-warming,0,3739594.storyGlobal Warming Enters Hurricane Debate
By CAIN BURDEAU | Associated Press Writer
7:44 AM CST, January 24, 2008
NEW ORLEANS - A lively and sometimes scrappy debate on whether global warming is fueling bigger and nastier hurricanes like Katrina is adding an edge to a gathering of forecasters here.
The venue for the 88th annual meeting of the American Meteorological Society could not have been more conducive to the discussion: The Ernest N. Morial Convention Center is where thousands of people waited for days during the storm to be evacuated from a city drowning in water and misery.
Although weather experts generally agree that the planet is warming, they hardly express consensus on what that may mean for future hurricanes. Debate has simmered in hallway chats and panel discussions.
A study released Wednesday by government scientists was the latest point of contention.
The study by researchers at the National Oceanic and Atmospheric Administration's Miami Lab and the University of Miami postulated that global warming may actually decrease the number of hurricanes that strike the United States. Warming waters may increase vertical wind speed, or wind shear, cutting into a hurricane's strength.
The study focused on observations rather than computer models, which often form the backbone of global warming studies, and on the records of hurricanes over the past century, researchers said.
"I think it was a seminal paper," Richard Spinrad, NOAA's assistant administrator for Oceanic and Atmospheric Research, said Wednesday.
"There's a lot of uncertainty in the models," Spinrad said. "There's a lot of uncertainty in what drives the development of tropical cyclones, or hurricanes. What the study says to us is that we need a higher resolution" of data.
Greg Holland, a senior scientist at the National Center for Atmospheric Research, said the new paper was anything but seminal. He said "the results of the study just don't hold together."
Holland is among scientists who say there is a link between global warming and an upswing in catastrophic storms. He said other factors far outweigh the influence of wind shear on how a storm will behave.
"This is the problem with going in and focusing on one point, a really small change," Holland said.
He had a sharp exchange Monday with Christopher Landsea, a NOAA scientist, during the AMS meeting.
While Holland sees a connection between global warming and increased hurricanes, Landsea believes storms only seem to be getting bigger because people are paying closer attention. Big storms that would have gone unnoticed in past decades are now carefully tracked by satellites and airplanes, even if they pose no threat to land.
The exchange, captured by National Public Radio, illustrates how emotional the global warming debate has become for hurricane experts.
"Can you answer the question?" Landsea demanded.
"I'm not going to answer the question because it's a stupid question," Holland shot back.
"OK, let's move on," a moderator intervened.
The passion was no surprise to the TV weather forecasters, academic climatologists, government oceanographers and tornado chasers attending the meeting.
"One thing I've learned about coming to this conference over the years is that very few people agree on anything," said Bill Massey, a former hurricane program manager at the Federal Emergency Management Agency.
"There's a legitimate scientific debate going on and a healthy one, and scientists right now are trying to defuse the emotion and focus on the research," said Robert Henson, the author of "The Rough Guide to Climate Change."
Whether global warming is increasing the frequency of major storms or reducing it, Henson said, lives are at stake.
"Let's say you have a drunk driver once an hour going 100 miles an hour in the middle of the night on an interstate," Henson said. "Say you're going to have an increase from once an hour to once every 30 minutes; that's scary and important. But you've got to worry about that drunk driver if it's even once an hour."
Massey agreed. "In 1992 we had one major storm. It was Hurricane Andrew. It was a very slow year. But one storm can ruin your day."
