Warming in Wyoming now rivals time
when glaciers vanished from Rockies
LARAMIE, Wyo. — If the 1930s were also hot, last year was one for the record books in large portions of the West. But more important is how this fits in with 30 years of steady heating, says Bryan Shuman, an associate professor of geology and geophysics at the University of Wyoming.
The current warming, he told the Jackson Hole News&Guide, in advance of a lecture there, is comparable to that which occurred when the last ice age ended abruptly 11,000 years ago. But unlike that time, change in the sun’s radiation and the Earth’s orbit do not explain the current warming. The only probable explanation is the fossil fuels being burned, sending heat-trapping carbon dioxide into the atmosphere. Much of that carbon comes from underground in Wyoming, particularly from coal.
“We really are experiencing meaningful change,” he told the newspaper. “It’s impossible to explain how this state became warmer without saying carbon dioxide or greenhouse gases played a part in the warming.”
Shuman runs a paleoclimate and paleoecology lab, which means he and his students examine past climates and the vegetation and animals that inhabited those times.
On his website, Shuman explains that the last 30 years have been exceptional warm, but 2012 was an extreme even among the recent years.
His examination of the past shows that Wyoming and other Rocky Mountain states have historically experienced extended periods of drought.
Tree-ring data from the Colorado River Basin has revealed extended periods of drought, lasting several decades, 1,000 years ago. But by studying the evidence of how lakes in the mountain headwaters have changed, he and his students believe that dry periods of the deeper past exceeded the severity of these megadroughts. Since the glaciers receded, dry periods have persisted for centuries, even millennia.
Nor are these small changes. In the mountains along the Colorado-Wyoming border, Shuman found evidence that lakes have dropped 30 per cent or more during the last 4,500 years.
In other words, what we think of as average won’t necessarily stay that way. The climate is usually on the move, and this time we’re juicing the change with a double latte of greenhouse gases.