Future wildfire seasons to be longer and burn more area

U.S. wildfire seasons by 2050 will be three weeks longer, twice as smoky and will burn a wider area in the western states, Harvard University researchers say. Environmental scientists at the school said their projections are based on internationally recognized climate scenarios, decades of historical meteorological data and records of past fire activity. Months of analysis was required, the researchers said, because at the local level wildfires are very difficult to predict. "We weren't altogether certain what we would find when we started this project," atmospheric chemist Lorreta J. Mickley said. "In the future atmosphere we expect warmer temperatures, which are conducive to fires, but it's not apparent what the rainfall or relative humidity will do. Warmer air can hold more water vapor, for instance, but what does this mean for fires?" The main factors influencing the spread of fires vary from region to region, the researchers found. "It turns out that, for the western United States, the biggest driver for fires in the future is temperature, and that result appears robust across models," Mickley said. "When you get a large temperature increase over time, as we are seeing, and little change in rainfall, fires will increase in size." That can't be good news for firefighters in the western United States who are currently battling dozens of fires in at least 11 states.