As world leaders convene in Copenhagen, Denmark, to debate the details of what could become a new international climate change treaty, and as Congress hammers out legislation to cut greenhouse gas emissions, the effects of climate change in western Montana begin to come into focus.
A recent study of temperature trends over the past 100-plus years conducted by five Montana scientists shows a decrease in extremely cold days and an increase in extremely hot days. Extremely cold days (less than or equal to –17.8 degrees Celsius) cease on average 20 days earlier and decline in number, the researchers found, while extremely hot days (greater than or equal to 32 degrees Celsius) show a three-fold increase in number and a 24-day increase in the seasonal window during which they occur.
The study also shows that western Montana has experienced a 1.33-degree Celsius rise in annual average temperatures, almost twice the 0.74-degree rise in global temperatures.
"The take-home message," says researcher Greg Pederson of the U.S. Geological Survey's Northern Rocky Mountain Science Center, "is what a 1.33- degree Celsius average annual change means in terms of changing extremes—both the heat extremes that drive things like bark beetle outbreaks, increase probabilities of large forest fires and stress our fisheries, and also the loss of the cool events that maintain snowpack...and also perform the function of killing off bark beetles when you get a lot of really cold days in a row."
The researchers state that "over the course of this next century we are committed to a warming climate," but a new Harris Poll finds that barely half of Americans—51 percent—agree that the release of carbon dioxide and other gases is leading to global warming, down from 71 percent just two years ago.
"I think those polls reflect more how stressed people are about the state of the economy and a lot of other things in our nation that it seems less important, at least now, to think about things like climate change," Pederson says.