Wednesday, July 29, 2009

Scientists expect wildfires to increase as climate warms in the coming decades

Harvard News: As the climate warms in the coming decades, atmospheric scientists at Harvard’s School of Engineering and Applied Sciences (SEAS) and their colleagues expect that the frequency of wildfires will increase in many regions. The spike in the number of fires could also adversely affect air quality due to the greater presence of smoke.

The study, led by SEAS Senior Research Fellow Jennifer Logan, was published last month in the Journal of Geophysical Research. In their pioneering work, Logan and her collaborators investigated the consequences of climate change on future forest fires and on air quality in the western United States.

Previous studies have probed the links between climate change and fire severity in the West and elsewhere. The Harvard study represents the first attempt to quantify the impact of future wildfires on the air we breathe. “Warmer temperatures can dry out underbrush, leading to a more serious conflagration once a fire is started by lightning or human activity,” says Logan. “Because smoke and other particles from fires adversely affect air quality, an increase in wildfires could have large impacts on human health.”

Using a series of models, the scientists predict that the geographic area typically burned by wildfires in the western United States could increase by about 50 percent by the 2050s due mainly to rising temperatures. The greatest increases in area burned (75-175 percent) would occur in the forests of the Pacific Northwest and the Rocky Mountains.

In addition, because of extra burning throughout the western United States, one important type of smoke particle, organic carbon aerosols, would increase, on average, by about 40 percent during the roughly half-century period….

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