Massive wildfires are on the increase in the Western US due to rising temperatures and worsening drought from climate change, and the trend could continue in the decades to come, new research suggests.
Overall, the number of large wildfires increased by a rate of seven fires a year from 1984 to 2011, while the total area damaged by fire increased at a rate of nearly 90,000 acres per year, according to the study, published this week in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).
The study comes against the backdrop of what could to be a disastrous year for fires in the West, especially drought-plagued California, which even saw fires in the normally quiet month of January.
Though relatively calm this week, "Expect dry and windy conditions to develop over the Southwest Tuesday and Wednesday," according to a forecast Friday from the National Interagency Fire Center in Boise. By May, "Above normal significant fire potential will expand over portions of Southern, Central and Northern California," the NIFC predicted earlier this month.
"Continuing changes in climate, invasive species and consequences of past fire suppression, added to the impacts of larger, more frequent fires, will drive further disruptions to fire regimes of the Western U.S.," according to the AGU study.
Scientists only looked at fires of greater than 1,000 acres in the study in 17 Western states, and found that man-made climate change was a very likely factor.
"We looked at the probability that increases of this magnitude could be random, and in each case it was less than 1%," said Philip Dennison, a geographer at the University of Utah and lead author of the paper.
To measure the fires, researchers used Landsat satellite data, which has only been available since 1984. Though wildfire records go back a couple of decades before that, Dennison said that information before satellites started taking measurements is not reliable.
"We have definitely seen a trend toward larger, more severe fires in the past decade or so," Randy Eardley, chief of external affairs at the NIFC, who was not part of the study, said via e-mail.
Eardley said that nationally, since 2000, three separate years have seen 9 million acres burned, while 8 million acres have burned in three other years. Before 2000, no year had seen 8 million acres burned.
This is not the first study to make the connection between climate change and Western fires. Research in the journal Ecosphere in 2012 found that "climate change will likely cause more frequent wildfires in the Western United States within the next 30 years and throughout North America and most of Europe by the end of the century."