Wildfires in the U.S. will be at least twice as destructive by 2050, burning around 20 million acres nationwide each year, according to a federal report released by the U.S. Department of Agriculture. Scientists from the U.S. Forest Service, who authored the report, found regions such as western Colorado — which already experienced its most destructive wildfire in history last summer — will face an even greater risk fire risk: those regions are expected to face up to a five-fold increase in acres burned by 2050.
The report’s findings are in line with previous studies on climate change’s relation to fire risk: a 2012 study found that wildfire burn season is two and a half months longer than it was 40 years ago, and that for every one degree Celsius temperature increase the earth experiences, the area burned in the western U.S. could quadruple. The findings are also in line with the observed impacts climate change is having on wildfires. Wildfires in 2012 burned a record 9.2 million acres in the U.S., and record-breaking heat and dry weather in Australia provided ideal conditions for at least 90 fires that raged through the country this January.
The report also outlines the other effects climate change will have on the forests of the U.S. The Rocky Mountain forests are expected to become hotter and drier as the planet warms, conditions that in addition to wildfires will lead to an increase in infestations of insects such as the bark beetle, which has already destroyed tens of millions of acres of U.S. forests. One species, the mountain pine beetle, has already killed 70,000 square miles of trees — area the size of Washington state. As winters become milder, weather becomes drier and higher elevations become warmer, bark beetles are able to thrive and extend their ranges northward. An increase in some species of bark beetle can actually increase the risk of forest fires in areas affected by the beetle — the study notes an outbreak of the mountain pine bark beetle, which attacks and kills live trees, created a “perfect storm” in 2006 in Washington, where affected lodgepole pines burned “with exceptionally high intensity.”
David Peterson, a U.S. Forest Service biologist who co-authored the report, told the Denver Post that the destruction the bark beetles have inflicted upon western forests in recent years has been unprecedented:
“We’re getting into extreme events that seem to be having more and more effects across broader landscapes.”
The report also predicts an increase of invasive plants and animals, as well as flooding and erosion due to increased rainfall, higher rain to snow ratios and more burned areas. It notes that U.S. forests offset 13 percent of the country’s carbon emissions, and as trees killed by insects and fire decompose, they’ll emit carbon themselves. Because of the sweeping impacts, the report, which is being finalized for the White House and Congress, calls on forest managers to make “climate-smart” practices, such as thinning fire-vulnerable forests, a priority.