Warmer, drier climate in the American West will increase the incidence and severity of forest fires, worsening air quality, reports a new study accepted for publication in the Journal of Geophysical Research – Atmospheres.
Using climate models to forecast the impact of moderate global warming on western U.S. wildfire patterns and atmospheric chemistry, Harvard University’s Jennifer Logan and colleagues forecast that organic carbon aerosols would increase by about 40 percent over the next 50 years due to a predicted 50 percent increase in the area burned by forest fires. Based on their analysis of a 25-year record of observed meteorology and fire statistics, the researchers expect the Pacific Northwest (75 percent rise in area affected by fires) and the Rocky Mountains (175 percent increase) to be particularly affected.
“Warmer temperatures can dry out underbrush, leading to a more serious conflagration once a fire is started by lightning or human activity,” said Logan. “Because smoke and other particles from fires adversely affect air quality, an increase in wildfires could have large impacts on human health.”
Diminished air quality could adversely affect those suffering from lung and heart conditions including asthma and chronic bronchitis.
The researchers plan to next study the impact of future wildfires and air quality over cities in California and the southwest.
Other recent research has reached similar conclusions. A study published three yeas ago in the journal Science found that the frequency of large forest fires has increased in the western United States since the mid-1980s as spring temperatures climbed, mountain snows melted earlier and summers got hotter. The findings suggested that climate change, not fire suppression policies and forest accumulation, is the primary driver of recent increases in large forest fires. Meanwhile a study published earlier this year in Science attributed a doubling in tree death rates in old-growth forests of the western United States to regional climate warming. The die-off has increased the risk of fire.