Climate Change Bringing More Severe Wildfires

Hilary Tuttle


October 1, 2013


By 2050, wildfire season will be three weeks longer and result in fires that are up to twice as smoky and spread considerably wider, based on calculations by a team of environmental scientists at the Harvard School of Engineering and Applied Sciences. While many groups have attempted to project the impact of climate change on severe weather events like storms and floods, the SEAS team took its research a step further to examine secondary phenomena that are largely impacted by meteorological factors, such as forest fires and air quality.

“I think what people need to realize is that, embedded in those curves showing the tiny temperature increases year after year are more extreme events that can be quite serious,” said Loretta J. Mickley, a senior research fellow in atmospheric chemistry at Harvard and coauthor of the study.

The researchers examined records of past weather conditions and wildfires to find the main factors influencing the spread of fires across the West. The team then developed mathematical models that link observed wildfire outcomes with variables like seasonal temperatures, relative humidity and the amount of dry fuel. Replacing the historical data with projections from the Intergovernmental Panel on Climate Change, they were then able to predict fire conditions through 2050.

By 2050, wildfire season could shift from mid-May through early October to a longer period from late April through mid-October—which would mean a season that is approximately 15% longer. According to the team’s calculations, the area burned in just the month of August could increase drastically across all of the regions examined, from a 65% larger fire in the Pacific Northwest to quadrupled burn areas in the Rocky Mountains Forest region. Smoke would increase between 20% and 100% by 2050, depending on the region, the researchers predict.

These findings come on the heels of one of the worst wildfire seasons in recent history, which claimed the lives of more than 26 firefighters, according to the U.S. Fire Administration. The Rim Fire in California’s Tuolomne County, which burned from late August through early September, was named the fourth-largest wildfire in California history after destroying more than 111 buildings and costing over $72 million to bring under control. And California represents only a fraction of the damage.

“Once assessments are complete, it is expected that aggregate U.S. insured losses from severe weather events in the month of August will reach $1 billion,” said Steven Bowen, senior scientist and meteorologist at Aon Benfield.

Hilary Tuttle is managing editor of Risk Management.