While a single wildfire cannot be linked to globalwarming, many scientists speculate that in a warming world thelikelihood of wildfires is higher. Part of the issue is heat-induceddrought. "Fires clearly depend on weather," says Senior Harvardresearcher Jennifer Logan.
Logan and her colleagues are investigatingthe consequences of climate change on wildfires, and the impact on U.S.air quality. She says their research indicates the warming of the earth'satmosphere "definitely" is linked to a longer summer and shorterwinter, which results in less snow and ice run off.
Wildfires tend to get more severe when the weather is very hot, and verydry for a long time where fuels can age. So far this year, more than68,000 wildfires have burned about 2.2 million hectares of U.S. land,which is not far off from the 10-year average (between 1999 and 2008)of about 2.3 million hectares burned annually, according to the NationalInteragency Fire Center.
As the climate warms in the comingdecades, however, Logan and her team of atmospheric scientists atHarvard's School of Engineering and Applied Sciences (SEAS) expect thatthe frequency of wildfires will increase in many regions. Theirresearch, published in the , suggeststhat the area of forest burnt by wildfires in the United States willincrease by more than 50 percent by 2050. Temperature was the primaryfactor impacting the wildfire surge, though dry vegetation also playeda role.
Tropical forests may be particularly affected by soaringgreenhouse gas emissions, noted scientist Chris Field of the CarnegieInstitute. "Tropical forests are essentially inflammable. You couldn'tget a fire to burn there if you tried. But if they dry out just alittle, the result can be very large and destructive," Field said.
TheHarvard study also represents the first attempt to quantify the impactof future wildfires on the air we breathe. Its findings are ominous."Because smoke and other particles from fires adversely affect airquality, an increase in wildfires could have large impacts on humanhealth," said Logan.
The researchers predict that an increase of morethan 50 percent in the burn area in the western United States by 2050would result in a near doubling of carbon-based aerosols into theatmosphere and "important consequences" for western U.S. air qualityand visibility.