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Experts: Unpredictable Storms, Extreme Heat, Will Hit Southwest Climate


TUCSON, Ariz. - A new report says international climate scientists are now 95 percent certain that humans are the dominant cause of climate change. Scientists in Tucson looked at the report and how those changes are playing out in the Southwest's climate.

The report from the Intergovernmental Panel on Climate Change is the first in six years. It warns of rising sea levels and faster ice melts if countries do not cut back on greenhouse gas emissions. Some of those emissions are at the highest they've been in nearly one million years.

A panel of University of Arizona scientists said the climate changes in the Southwest aren't in the future, they're happening already.

"We're warming as fast as anywhere in the lower 48 states, faster than most of the lower 48 states," said geoscientist Julie Cole.

Cole said in the Southwest desert, you can expect warmer nights and hotter days. In areas depending on monsoon rains, like Arizona, those rains will be stronger, but with longer dry periods in between. Unpredictable weather changes are something residents will have to grow used to.

"What's your best year in Arizona? When it rained when you wanted it to rain and it rained as much as you wanted it to rain and it rained in their right season. We can probably not count on that kind of situation occurring as much as we did in the past," said Mike Crimmins, a U of A climate specialist.

Scientists in the desert are also looking at lower river flows, drier soils and faster water evaporation. Bob Udall, director of the University of Colorado Western Water Assessment, predicts a 5 to 20 percent decrease in the Colorado River flow in the next 40 years.

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