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Will Utah be ready for a drier, hotter climate?

First Published      Last Updated Feb 22 2015 09:51 am

Megadrought » NASA study forecasts an 80 percent chance of a 35-year drought by mid-century in the Southwest.

The specter of drought hanging over the Southwest is already pretty dire, with forests drying out into beetle-killed tinderboxes and reservoir levels plunging. But the current dry spell may barely register in comparison with what has happened in the distant past and could happen in the near future, according to research released this month.

And we may have ourselves to blame.

If the trajectory of greenhouse-gas emissions continues, human-caused climate change would drive up the chance of the Southwest experiencing a "megadrought" lasting 30 to 35 years to 80 percent, said lead author Benjamin Cook, a climate scientist with NASA's Goddard Institute for Space Studies.

Past droughts, such as the Dust Bowl of the 1930s, were temporary changes to an otherwise-stable environment, but global climate change is creating a new normal.

"In the future, we are looking at a really significant transition to drier conditions that will be with us for a long time," Cook said. "We will still have natural variability, but happening with a much drier baseline."

If this scenario plays out, such a prolonged period of high temperatures and low snow would wreak havoc for water planners, already struggling to cope with shrinking rivers and a booming population, which is expected to double in Utah in coming decades.

Current conservation strategies may not be enough to cope with droughts that exceed 20 years.

"The real challenge," Cook said, "is adapting our strategies for water shortages to these more extreme events."

"Is there a trend here?" • Recent studies have forecast that global climate change could increase aridity in the Southwest, but the NASA-led study is the first to indicate such drying may dwarf past droughts that are measured in tree rings.

But Utah's snow-survey supervisor, Randy Julander, is skeptical.

"Whenever you have modeled results that predict not just extremes, but exceptional, unbelievably rare extremes, a lot of caution goes up immediately. Is there a chance it could happen? Absolutely. We have seen it in the paleoclimatological record," said Julander, a hydrologist with the federal Natural Resources Conservation Service.

Still, evidence of a human role in climate change continues to mount, with most of the hottest years on record occurring during this century. According to the National Oceanic and Atmospheric Administration, last year was the world's hottest on record and last January was the second warmest.

In Utah, 2014 was the state's fourth-warmest year — despite the mild, damp summer. Salt Lake City saw 220 days with temperatures above normal and nine days set heat records.

This year has gotten off to a balmy, snow-free start with numerous record-high temperatures. So far in February, record-high temperatures have been tied or broken 294 times at Utah locations, while high minimum temperature records have been tied or broken 193 times, according to a NOAA database.

State climatologist Robert Gillies cautioned against reading too much into such observations.

"It's the inherent variability of the West's weather that makes life difficult for climate scientists," Gillies said. "The big question is: Is there a trend here? Is there a trend where this will happen more often?"

The answer may be yes. Records show Utah has warmed during the past 50 years and at a rate much faster than the global average, according to Gillies.

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