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This year aside, Utah's drying up

Published April 1, 2008 12:38 am

Floods may come, but overall aridity will increase, scientists say
This is an archived article that was published on sltrib.com in 2008, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

LOGAN - After the hottest summer on record, Utah's snowpack future was looking a little grim. But a quick turnaround in December and steady snowfall throughout the winter and even spring has brought snow levels along the Wasatch Front to about 120 percent of the average.

Now the National Weather Service is keeping a close watch on flood potential around the state, hydrologist Brian McInerney said Monday during the keynote address of the two-day Spring Runoff Conference at Utah State University.

It would appear the drought is over, at least for now. But Utah still remains at the epicenter of global warming in the United States, becoming ever more arid, said climate researcher Roger Pulwarty of the National Oceanic & Atmospheric Administration.

The two scientists weren't disagreeing - they were pointing at the relationship between drought and aridity, key to understanding how to plan for living in a hotter, drier Southwest.

"The problem is not when you have disagreement between researchers and scientists; the problem is when you have agreement - because then you have to do something," said Pulwarty.

But how do you prepare for your future when all water management builds on the notion that the future will look like the past, which it won't?

First step: Don't get complacent because this winter was wet, said Pulwarty.

Lakes Powell and Mead were collectively at 55 percent capacity as of February, he said. It would take 15 years of average runoff conditions to fill them. Even if that happened - and studies of the Colorado River Basin suggest it won't - "let's not deceive ourselves that that takes care of a drought," Pulwarty said.

McInerney said that weather forecasting is fairly reliable only five to seven days in advance. But climate prediction takes a longer view. Right now, the Weather Service's climate prediction center expects the continuation of an equatorial Pacific Ocean La Niña this year.

When the Pacific is cooler than normal, as has been the case, deserts grow drier and the Pacific Northwest is wetter. This year's storm cycles have turned that assumption on its head, McInerney said. And while there shouldn't be a short-term change, the ocean is warming off Ecuador and northeastern Australia.

Warming oceans send more heat into space, where it's trapped under a blanket of carbon dioxide largely resulting from human activity, such as burning coal for energy.

In the desert Southwest, the sun evaporates soil moisture, carrying heat off as water vapor. Then the sun bakes the dry ground to dust. Vegetation dies, as do the animal species that depend on it. That's called drought - an event in a permanently arid climate - and is thought to self-perpetuate because baked ground with little vegetation loses its ability to absorb carbon dioxide, further contributing to temperature increases and aridity.

Pulwarty - one of the researchers with the Intergovernmental Panel on Climate Change, which shared the 2007 Nobel Peace Prize with former Vice President Al Gore - called for adaptive planning based on good data. But he criticized a recent study by two scientists at the Scripps Institution of Oceanography that found Lake Mead and Lake Powell might dry up by 2021.

The "alarmist" study left out critical information about tributary runoff, Pulwarty said. Worse, he said, the study's dire prediction is diverting attention from the serious planning needed to address the reality of living in the arid West.

The problem is not when you have disagreement . . . the problem is when you have agreement - because then you have to do something.

-Climate researcher Roger Pulwarty of the National Oceanic & Atmospheric Administration.