Climate change is accelerating the assault on Western US forests, bringing threats like drought, insect infestations and wildfires, and if left unchecked large swaths of lush greenery could be "fundamentally altered," scientists warned in a new report released Wednesday.
Some of America's most cherished landscapes could completely transform as we know them, including Glacier, Rocky Mountain, and Yellowstone national parks.
The iconic pine and aspen forests of the Rocky Mountains, for one, are dying off at an alarming rate. And with climate change showing no signs of letting up, Colorado alone could lose 45 percent of its prized aspen over the next 45 years, according to the report, released by the Union of Concerned Scientists (UCS) and the Rocky Mountain Climate Organization (RMCO).
"The wildfires, infestations and heat and drought stress are the symptoms; climate change is the underlying disease," Jason Funk, report co-author and senior climate scientist at UCS, said in a statement.
According to the report's projections - based on data from the US Forest Service - if emissions continue at current rates, by 2060 the area climatically suitable in the Rocky Mountains for lodgepole pine could decline by about 90 percent, for ponderosa pine by about 80 percent, for Engelmann spruce by about 66 percent and for Douglas fir by about 58 percent.
"So far, we have had relatively modest climate changes, but they have already jolted our forests," added Stephen Saunders, report co-author and president of RMCO.
Among the top concerns are the beetle bark outbreaks, which alone have killed 46 million acres of pine trees across the West - an area nearly the size of Colorado. Wildfires, too, are becoming more common. From 1984 to 2011, they have risen 73 percent among Western forests.
But possibly even more troubling is that trees in general are dying at twice the normal rate, for no apparent reason. Scientists suspect that hotter and drier conditions could be the culprit.
All these imperiled species of trees grow in certain areas depending on the climate, which dictates how hot or cold summers and winters get. If climate change alters these conditions, trees could cease to grow in their natural habitat.
"If we continue changing the climate, we may bring about much more fundamental disruption of these treasured national landscapes," said Saunders.