Researchers in the United States have warned that drier conditions will lead to more forest fires across the country in coming years. The warning comes after one of the hottest, driest summers on record in North America, which led to a costly drought in the Midwest, and sparked price hikes for major crops.

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As well as revealing how climate change would affect the length and strength of fire season, the scientists, working with NASA, also produced data on the carbon emissions of forest fires. Doug Morton, spokesperson for the researchers, said from San Francisco, "Climate models project an increase in fire risk across the US by 2050, based on a trend toward drier conditions that favour fire activity and an increase in the frequency of extreme events."

Looking at climate modelling, using satellite data and referring to recent patterns in US forest fires, the NASA team calculated results for low and high greenhouse gas emissions scenarios. They found that, in both low and high-GHG scenarios "fire seasons are expected to be longer and stronger across all regions of the US in the next 30-50 years." The researchers added, "Specifically, high fire years like 2012 would likely occur two to four times per decade by mid-century, instead of once per decade under current climate conditions."

In August 2012 alone, the US burned area topped 2.5 million hectares, though 2011 was a record fire year, in which 3.2 million hectares burned. NASA researchers also found that, greenhouse gas emissions from fires have increased by 250 percent.

Hsiao-Wen Lin of the University of California, Irvine added that, from a fire and emissions management perspective, wildfires are part of a bigger picture.  She elaborated that satellite data show agricultural and prescribed fires account for 70 percent of the total number of fires in the continental US; agricultural fires have increased 30 percent in the last decade.

In contrast with wildfires, agricultural and prescribed fires are less affected by climate, especially drought, during the fire season. Lin said, "That means there is greater potential to manage fire emissions, even in a future, drier climate with more wildfires. We need to use cost-benefit analysis to assess whether reductions in agricultural fire emissions – which would benefit public health – would significantly impact crop yields or other ecosystem services."

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