Climate Model Predicts Dramatic Changes Over Next 100 Years
Purdue University supercomputers say more extreme temperatures and precipitation on the way.
Compiled by staff
Published: Nov 2, 2005
The most comprehensive climate model to date of the continental United States predicts more extreme temperatures throughout the country and more extreme precipitation along the Gulf Coast, in the Pacific Northwest and east of the Mississippi.
The climate model, run on supercomputers at Purdue University, takes into account a large number of factors that have been incompletely incorporated in past studies, such as the effects of snow reflecting solar energy back into space and of high mountain ranges blocking weather fronts from traveling across them, says Noah Diffenbaugh, the team's lead scientist. Diffenbaugh says a better understanding of these factors — coupled with a more powerful computer system on which to run the analysis — allowed the team to generate a far more coherent image of what weather we can expect to encounter in the continental United States for the next century. Those expectations, he says, paint a very different climate picture for most parts of the country.
"This is the most detailed projection of climate change that we have for the U.S.," says Diffenbaugh, an assistant professor of earth and atmospheric sciences in Purdue's College of Science and a member of the Purdue Climate Change Research Center. "And the changes our model predicts are large enough to substantially disrupt our economy and infrastructure."
The team's projections are not necessarily about specific weather events, Diffenbaugh says. "But they do give us a good idea about what kind of weather to expect over the long run in a particular part of the country."
Some of these expectations include:
• In the northeastern United States — roughly 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 says. "The area could experience temperatures in that range lasting for periods of up to two months by century's end."
• The desert Southwest will experience more heat waves of greater intensity, combined with less summer precipitation. Water is already at a premium in the four-corners states and southern Nevada and, as years pass, even less water will be available for the region's burgeoning populations, with extreme hot events increasing in frequency by as much as 500%.
• The Gulf Coast will be hotter and will receive its precipitation in greater volumes over shorter time periods. "The region actually will get more rainfall than it does now, but it will not be steady," Diffenbaugh says. "We project more dry spells punctuated by heavier rainfalls. We need to perform further analyses to understand how much of this is related to tropical cyclone activity."
•Similarly, the continental United States will experience an overall warming trend: Temperatures now experienced during the coldest two weeks of the year will be a past memory, and winter's length will diminish as well, according to the model.
The model, Diffenbaugh says, assumes that greenhouse gases will attain a concentration more than twice their current levels, but he says he is confident that the model's performance gives as accurate a picture of the future as we can hope for at the moment.
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