Climate Change Fueling Wildfire Season

Climate change in the western United States seems to have amplified forest wildfire activity in the region over the last 35 years, according to new research published in the 8 July 2006 issue of the journal Science.

In their study, Anthony Westerling and colleagues compiled a database of large forest wildfires in the western United States for the period from 1970 to 2003 and compared those data with corresponding measurements of climate, hydrology and land-surface conditions.

They found that wildfire activity increased suddenly in the mid-1980s, with large fires becoming more frequent, fires becoming longer, and the wildfire season also becoming longer. The results indicate that fires and hydroclimate (which involves spring and summer temperatures as well as snowmelt) are closely related and that climate variation has been the primary cause of the increase in fires during the period of their study, although land-use changes can also be important.

Kathy Wren

6 July 2006