5 August 2009

As climate warms, expect more wildfires, poorer air quality

As the climate warms in the coming decades, atmospheric scientists at Harvard’s School of Engineering and Applied Sciences (SEAS) and their colleagues expect 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.

This graph shows the percentage increase in area burned by wildfires, from the present-day to the 2050s, as calculated by the model of Spracklen.

The study, led by SEAS Senior Research Fellow Jennifer Logan, was in the 18 June issue of Journal of Geophysical Research. This 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 lightening 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.”

To conduct the research, the team first examined a 25-year record of observed meteorology and fire statistics to identify those meteorological factors that could best predict area burned for each ecosystem in the western U.S.

To see how these meteorological factors would change in the future, they then next ran a global climate model out to 2055, following a recognized scenario in greenhouse gas emissions.

As a last step, the researchers used an atmospheric chemistry model to understand how the change in wildfire activity would affect air quality.

The authors expect the work will help policymakers gauge the “climate penalty” related to ongoing efforts to reduce air pollution across the U.S.

For related information, go to www.isa.org/environmental.