Global Warming Is Expected to Raise Hurricane Intensity
By ANDREW C. REVKIN

Published: September 30, 2004


Global warming is likely to produce a significant increase in the intensity
and rainfall of hurricanes in coming decades, according to the most
comprehensive computer analysis done so far.

By the 2080's, seas warmed by rising atmospheric concentrations of heat-
trapping greenhouse gases could cause a typical hurricane to intensify
about an extra half step on the five-step scale of destructive power, says
the study, done on supercomputers at the Commerce Department's Geophysical
Fluid Dynamics Laboratory in Princeton, N.J. And rainfall up to 60 miles
from the core would be nearly 20 percent more intense.

Other computer modeling efforts have also predicted that hurricanes will
grow stronger and wetter as a result of global warming. But this study is
particularly significant, independent experts said, because it used half a
dozen computer simulations of global climate, devised by separate groups at
institutions around the world. The long-term trends it identifies are
independent of the normal lulls and surges in hurricane activity that have
been on display in recent decades.

The study was published online on Tuesday by The Journal of Climate and can
be found at http://www.gfdl.noaa.gov/reference/b...004/tk0401.pdf.

The new study of hurricanes and warming "is by far and away the most
comprehensive effort" to assess the question using powerful computer
simulations, said Dr. Kerry A. Emanuel, a hurricane expert at the
Massachusetts Institute of Technology who has seen the paper but did not
work on it. About the link between the warming of tropical oceans and storm
intensity, he said, "This clinches the issue."

Dr. Emanuel and the study's authors cautioned that it was too soon to know
whether hurricanes would form more or less frequently in a warmer world.
Even as seas warm, for example, accelerating high-level winds can shred the
towering cloud formations of a tropical storm.

But the authors said that even if the number of storms simply stayed the
same, the increased intensity would substantially increase their potential
for destruction.

Experts also said that rising sea levels caused by global warming would
lead to more flooding from hurricanes - a point underlined at the United
Nations this week by leaders of several small island nations, who pleaded
for more attention to the potential for devastation from tidal surges.

The new study used four climate centers' mathematical approximations of the
physics by which ocean heat fuels tropical storms.

With almost every combination of greenhouse-warmed oceans and atmosphere
and formulas for storm dynamics, the results were the same: more powerful
storms and more rainfall, said Robert Tuleya, one of the paper's two
authors. He is a hurricane expert who recently retired after 31 years at
the fluid dynamics laboratory and teaches at Old Dominion University in
Norfolk, Va. The other author was Dr. Thomas R. Knutson of the Princeton
laboratory.

Altogether, the researchers spawned around 1,300 virtual hurricanes using a
more powerful version of the same supercomputer simulations that generates
Commerce Department forecasts of the tracks and behavior of real
hurricanes.

Dr. James B. Elsner, a hurricane expert at Florida State University who was
among the first to predict the recent surge in Atlantic storm activity,
said the new study was a significant step in examining the impacts of a
warmer future.

But like Dr. Emanuel, he also emphasized that the extraordinary complexity
of the oceans and atmosphere made any scientific progress "baby steps
toward a final answer."

http://www.nytimes.com/2004/09/30/sc...tml?oref=login
--
We today have a president of the United States who looks like he is the
son of Howdy Doody or Alfred E. Newman, who isn't smarter than either of
them, who is arrogant about his ignorance, who is reckless and
incompetent, and whose backers are turning the United States into a pariah.

What, me worry?