Over 29,000 wildfires have scorched more than 2.6 million acres of land already this year. Last year’s fire season was the most severe on record, burning more than 10 million acres – roughly twice the size of Massachusetts. Rising global temperatures and unrelenting drought contribute to the longer fire seasons. Average annual temperatures rose by 1.9 degrees Fahrenheit in the last decade, and snowpacks are now melting up to four weeks earlier in the year, leaving landscapes drier and causing fire seasons to start sooner. While Alaska’s wildfire season usually begins in April or May, this year the state saw its first flames in late February, according to the report. Warmer conditions in the fall mean that the fires burn longer too. Mike Ferris, a public information officer who has worked with the U.S. Forest Service for 39 years. “Now it seems like the fire season is year-round.”  If global temperatures continue to increase, the National Wildlife Federation predicts, the area of forests burned is projected to double in size by the end of the century. Lack of rainfall is another contributing factor. The last decade’s drought in the western U.S. has created the driest conditions in 800 years, according to the most recent National Climate Assessment study. The study also predicts that droughts in the Southwest as well as heat waves everywhere will continue to become more intense, leaving dead plants and dry debris prone to flames.  Warmer weather conditions accelerate the growth of invasive weeds that act as fire fuel and lead to insect infestations that kill trees, adding to the stockpile of flammable material.  Erratic weather patterns and more severe thunderstorms make lightning strikes a more frequent source of wildfire ignition.

Because people have tried for decades to suppress all wildfires, even harmless ones, Staudt said, unsafe levels of combustible materials have built up in forests. Drought and rising temperatures have increased the risk that this natural fuel will catch fire, creating blazes that are bigger and burn longer.

There was an annual average of 140 large (more than 1,000 acres) wildfires in the 1980s, but that increased to 250 per year in the 2000s, according to a study published in Nature Communications last year.