Drought and rising temperatures have created a 30-year trend of worsening and more frequent wildfires in the western United States, a study confirms, and researchers say it could continue.
Climate change xxx xx will likely see temperatures continue to rise and drought turn even more severe during the coming decades, says Philip Dennison, a geography professor at the University of Utah.
In a study submitted to the journal Geophysical Research Letters, Dennison and his research partners say wildfires consuming more than 1,000 acres increased by a rate of seven fires a year between 1984 and 2011 in the region extending from California to Nebraska.
At the same time, the total area burned by the fires grew by almost 90,000 acres annually, he says, and the largest of the wildfires grew bigger by 350 acres annually.
"We looked at the probability that increases of this magnitude could be random, and in each case it was less than 1 percent," Dennison says.
Satellite data was used to gauge the extent of the areas burned by large wildfires beginning in 1984, and climate records for the same period were analyzed for levels of rainfall and seasonal temperatures.
The researchers say they studied nine distinct "ecoregions," areas ranging from grasslands to warm deserts to forested mountains in the western U.S. that share similar vegetation and climate.
A link between ongoing drought and fire activity emerged from the data, researchers say.
"Twenty-eight years is a pretty short period of record, and yet we are seeing statistically significant trends in different wildfire variables -- it is striking," says study co-author Max Moritz, a wildfire specialist at the University of California, Berkeley.
The findings strongly suggest it's large-scale climate changes over large regions, rather than more localized factors, that are driving an increase in wildfire activity, the researchers say.
A number of climate models have projected an increase in global wildfire patterns as severe droughts and temperature increases become more severe in coming decades as a result of warming, they say.
"Most of these trends show strong correlations with drought-related conditions which, to a large degree, agree with what we expect from climate change projections," Moritz says.
