Climate models project increase in US wildfire risk

NASA: 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.

Doug Morton of NASA's Goddard Space Flight Center in Greenbelt, Md., presented the new analysis of future U.S. fire activity. The analysis was based on current fire trends and predicted greenhouse gas emissions.  "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 analysis by Morton and colleagues used climate projections, prepared for the Fifth Assessment Report of the United Nations Intergovernmental Panel on Climate Change, to examine how dryness, and therefore fire activity, is expected to change.

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.

Through August of this year, the U.S. burned area topped 2.5 million hectares (6.17 million acres), according to a fire emissions database that incorporates burned area estimates produced from observations by the Moderate Resolution Imaging Spectroradiometer instruments on NASA's Aqua and Terra satellites. That is short of the record 3.2 million hectares (7.90 million acres) burned in 2011, but exceeds the area burned during 12 of the 15 years since record keeping began in 1997. This and other satellite records, along with more refined climate and emissions models, are allowing scientists to tease out new information about fire trends....