Warming Oceans Make Strongest Storms Stronger - Study
US: September 4, 2008
WASHINGTON - As the world's oceans get warmer, the strongest tropical storms
get stronger, climate scientists reported on Wednesday as the remnants of
Hurricane Gustav spun out over the central United States.
"If the seas continue to warm, we can expect to see stronger storms in the
future," James Elsner of Florida State University said.
"As far as this year goes, as a season, we did see the oceans warm and I
think there's some reason to believe that that's the reason we're seeing the
amount of activity we are."
Gustav made landfall on Monday just west of New Orleans; three more storms
churned toward the US mainland on Wednesday.
The National Oceanic and Atmospheric Administration predicts 12 to 16
tropical storms between June 1 and Nov. 30 this year, with six to nine
hurricanes and two to five major hurricanes.
Many climate scientists have linked stronger storms to rising sea surface
temperatures in the North Atlantic and elsewhere, under the so-called heat
engine theory: because warm tropical cyclones feed on warm water, the warmer
the water, the more intense the storm.
US researchers looked at 26 years of satellite data, from 1981 to 2006, and
determined that the strongest storms got stronger as a result of increasing
ocean warmth.
"It's almost like a survival-of-the-fittest argument," said Elsner, whose
study is published in the journal Nature. Overall, tropical waters that
breed cyclones have warmed by about 0.6 degrees F (0.33 degree C) since
1981.
The heat engine theory suggests all storms should strengthen as the ocean's
surface gets hotter, but in reality, few tropical cyclones achieve their
full maximum potential intensity.
A cyclone's intensity can be cut by other factors, such as where they form,
how close they are to land, El Nino patterns and solar activity, the
researchers said.
Strong storms seem able to overcome these factors and gather more fuel from
warming waters, Elsner said.
The study's findings are in line with projections made last year by the UN's
Intergovernmental Panel on Climate Change, which said there may be more
intense storms due to global warming.
The panel said "more likely than not" that a trend of intense tropical
cyclones and hurricanes was caused by human activity.
Elsner's study made no reference to any human cause for rising temperatures
in the world's oceans.
Story by Deborah Zabarenko, Environment Correspondent
REUTERS NEWS SERVICE
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