Extreme weather will be 21st-century norm
Tuesday, November 01, 2005
BY KITTA MacPHERSON
Extreme temperatures. Drenching rain.
It's all coming this century.
The forecasts are being produced courtesy of what is being billed
as "the most comprehensive climate model to date of the continental
U.S." The climate model, a mathematical representation of reality
that projects weather trends, was created by scientists at Purdue
The vast computer program takes into consideration factors that have
been ignored or given short shrift before -- such as the effects of
snow reflecting solar energy back into space and the consequences of
high mountain ranges blocking weather fronts traveling across them --
according to Noah Diffenbaugh, the team's lead scientist.
A more powerful computer and a better understanding of these facts
allowed the team to generate a far more clear image of what weather
citizens can expect to encounter over the next 100 years, he said.
"This is the most detailed projection of climate change that we have
for the U.S.," Diffenbaugh said. "And the changes our climate model
predicts are large enough to substantially disrupt our economy and
Some of these projections are:
In the northeastern U.S. -- the region east of Illinois and north of
Kentucky -- summers will be longer and hotter. "Imagine the weather
during the hottest two weeks of the year," Diffenbaugh said. "The
area could experience temperatures in that range lasting for periods
up to two months by century's end."
The desert Southwest will experience more heat waves of greater
intensity, combined with less summer precipitation.
The Gulf Coast will be hotter and will receive its precipitation in
greater volumes over shorter time periods.
The continental U.S. will experience an overall warming trend.
Temperatures now experienced during the two coldest weeks of the year
will be a thing of the past. Winter's length will diminish, as well.
Climate models are sophisticated computer codes that attempt to
include as many details as possible about the complex workings of the
environment. Hundreds of dynamic processes, such as ocean currents,
cloud formations, vegetation cover and -- of particular import -- the
increase in atmospheric greenhouse gases are programmed into the
computers. The machines then attempt to calculate the effects on
square-shaped plots of land that represent small pieces of the
earth's surface. The smaller these squares are, the finer
"The study is the latest and most detailed simulation of climatic
change in the United States," said Stephen Schneider, a climate
expert at Stanford University in California.