PHOENIX (By Shaun
McKinnon, Arizona Republic) November 8, 2005
Arizona
will be a hotter, drier place 50 or 60 years from now, sweltering
through intense heat waves and nearly rainless summers, according to a
new long-term climate model.The model, produced by scientists at Purdue University, predicts more extreme weather events across the country, with wetter conditions along the Gulf Coast and in the Northwest and hotter summers in the Northeast and Southwest.
Temperatures will climb almost everywhere, based on the model, which assumes that greenhouse gases will reach higher levels, contributing to climate change.
The changes will be serious enough to disrupt the nation's economy and infrastructure, the scientists said.
Noah Diffenbaugh, team leader on the study, said the model is the most-detailed projection of climate change that it has ever produced and was meant, in part, to answer complaints that climate change studies weren't backed up with enough detail.
"We can never be completely certain of the future, but it's clear that as we consider more and more detail, the picture of future climate change becomes more and more severe," Diffenbaugh said. "It appears climate change is going to be even more dramatic than we previously thought."
The climate models use hundreds of variables, including ocean currents, cloud formations, vegetation cover and the levels of greenhouse gases in the atmosphere.
This model allowed scientists to zero in on geographical squares as small as 25 kilometers, about 15 miles, to a side.
Among the projections for the rest of the century:
• Arizona and the desert Southwest will see intense heat waves and receive less summer precipitation. Over time, that will shrink the water supply and increase demand, leaving more people to fight over less water. The most-extreme heat waves could increase in frequency by as much as 500 percent, the models predict.
• The Gulf Coast will receive more rain in shorter bursts. The team wants to see how that might figure in to tropical weather, especially hurricanes.
• Summer will be longer and hotter in an area east of Illinois and north of Kentucky.
• Overall average temperatures will climb almost everywhere in the country. Temperatures typical during the coldest two weeks of the year "will be a past memory," the study predicted, "and winter's length will diminish as well."
The study is one of several in the past year to suggest that climate change will begin to affect the West.
A separate model released this fall predicted warmer winters and drier summers.
