Climate Models Project Increase in U.S. Wildfire Risk!!!

Climate Models Project Increase in U.S. Wildfire Risk

WASHINGTON -- Scientists using NASA satellite data and climate models have projected drier conditions likely will cause increased fire activity across the United States in coming decades. Other findings about U.S. wildfires, including their amount of carbon emissions and how the length and strength of fire seasons are expected to change under future climate conditions, were also presented Tuesday at the annual meeting of the American Geophysical Union in San Francisco.

"Climate models project an increase in fire risk across the U.S. by 2050, based on a trend toward drier conditions that favor fire activity and an increase in the frequency of extreme events," Morton said.

The researchers calculated results for low and high greenhouse gas emissions scenarios. In both cases, results suggest more fire seasons that are longer and stronger across all regions of the U.S. in the next 30-50 years. Specifically, high fire years like 2012 would likely occur two to four times per decade by mid-century, instead of once per decade under current climate conditions.

As the U.S. land area burned by fire each year has increased significantly in the past 25 years, so too have the emissions. Carbon dioxide emissions from wildfires in the western U.S. have more than doubled since the 1980s, according to Chris Williams of Clark University in Worcester, Mass.

The satellite-based view allowed Williams and his colleagues to quantify how much carbon has been released from fires in the U.S. West. The team used data on fire extent and severity derived from Landsat satellites to calculate how much biomass is burned and killed, and how quickly the associated carbon was released to the atmosphere. The team found carbon emissions from fires have grown from an average of 8 teragrams (8.8 million tons) per year from 1984 to 1995 to an average of 20 teragrams (22 million tons) per year from 1996 to 2008, increasing 2.4 times in the latter period.

From a fire and emissions management perspective, wildfires are not the entire U.S. fire story, according to research by Hsiao-Wen Lin of the University of California at Irvine. Satellite data show agricultural and prescribed fires are a significant factor and account for 70 percent of the total number of active fires in the continental U.S. Agricultural fires have increased 30 percent in the last decade.

For images and additional information on this research, visit:

[link to www.nasa.gov] -fire.html