Wildfires are sweeping across Canada and Alaska and they're getting worse every year

The usually icy northern corners of the Americas are on fire–and they’re likely to burn for longer each wildfire season, according to a new paper published in the journal Nature Communications. As the planet has grown warmer over the last three decades, the length and severity of wildfire seasons has increased by 18.7% globally, the report says.

The study, from researchers in Australia and the U.S., looked at wildfire trends from 1979 to 2013. Fire seasons have become longer in every continent except Australia, they wrote.

Nearly 4.5 million acres of land have burned in Alaska so far this season, the Washington Post reports, with the numbers rising. Between Alaska and Canada, the total so far adds up to more than 11 million acres—an area three times the size of Connecticut, as the Post tells us.

The Canadian province of Saskatchewan has been blanketed in thick smoke from raging fires, prompting more than 10,000 evacuations, health warnings from Canada’s environment agency and eerie photos on Instagram:

“The situation is Canada is extreme right now, specifically in Western Canada,” Kerry Anderson, research scientist with the Canadian Forest Service, told NPR. “Western Canada has seen about three times the area that’s normally burned for this time of year.”

In California, the combination of warmer temperatures and drought conditions have authorities bracing for a severe fire season. Although up to this point it hasn’t been more severe than usual, the season did start early, CBS News reports.

In fact, the western part of the U.S. has been so dry, the Washington Post reports, that a fire has been smouldering for three months in Washington’s Olympic National Park, an area that’s home to two rainforests.

The Nature Communication report also found that, especially in the last fifteen years, the area of the Earth’s surface that’s vulnerable to wildfires has doubled–partly due to drier conditions and warmer ocean temperatures in some places.

“If these fire weather changes are coupled with ignition sources and available fuel, they could markedly impact global ecosystems, societies, economies and climate,” the report’s authors wrote.