About half of the increase in forest fires in the western United States can be attributed to climate change, according to a study released Monday.
The study, done by Columbia University and University of Idaho scientists, argues that increased temperatures and the resulting dryness of the landscape has led to larger forest fires. According to the study, forest fires since 1984 have burned 16,000 more square miles than they would have if climate change were not occurring.
Many scientists believe climate change, and the subsequent warming of the globe, is caused by the burning of fossil fuels.
“No matter how hard we try, the fires are going to keep getting bigger, and the reason is really clear,” said Park Williams, a bioclimatologist at Columbia University and one of the study’s coauthors. “Climate is really running the show in terms of what burns. We should be getting ready for bigger fire years than those familiar to previous generations.”
Climate scientists have long warned that global warming would cause more forest fires, but the study tries to show that forest fires are already increasing due to the effects of climate change. The study reports climate change is responsible for about 55 percent of the increasing dryness of the western U.S.
Western forest fires began increasing in the 1980s, according to the study. The researchers used the amount of land area burned, the number of large fires and the length of the fire season as data points for the study.
Average temperatures in parts of the western U.S. covered in forest have increased about 2.5 degrees since 1970. That increases the dryness of the area and allows more fires to burn more wildly, the study argues.
However, not all of that is due to human activity. According to the study, a “long-term natural climate oscillation over the Pacific Ocean” causes storms to avoid the western U.S.
Firefighting itself also is causing forest fires to increase, according to the study. Suppressing forest fires means areas that should burn naturally do not, leaving lots of dry fuel for future forest fires.
“We’re seeing the consequence of very successful fire suppression, except now it’s not that successful anymore,” said John Abatzoglou, a geography professor at the University of Idaho.
