Canada's "hellish" wildfire season defies the calendar

• While five provinces and territories, stretching from Nova Scotia to the Northwest Territories, saw record amounts of land burned this season, western Canada has been hit the hardest, she said in an interview.
• "Things have just continued to play out in kind of a hellish way in western Canada," she said.
• During the past few days, smoke from wildfires in British Columbia and the Northwest Territories has tinted the skies over Greenland and northern Europe.

These fires are burning at a time of year when Canada's fire activity tends to be on a sharp decline.

• "The sudden increase in the fire emissions for Canada between 23-25 September was very surprising for the time of year, and following 21 weeks of continuous fires," Mark Parrington, a senior scientist with the Copernicus Atmosphere Monitoring Service, said via email.
• He said that three-day emissions total was about 50 megatonnes of carbon, "As much as some previous summer or annual total estimated fire emissions for the country,"

Of note: A little over 70,000 square miles of land has burned since May in Canada, equivalent to the entire state of Washington.

• "This is going to go until we have deep snow," Turetsky said.

Why it matters: Not only have the fires displaced tens of thousands of Canadians during the past several months, but they have also caused historically poor air quality in the U.S.

• With hundreds of wildfires still burning, there is the potential for more air quality degradation in the U.S. through the fall.

Zoom in: In addition, the fires have emitted at least as much carbon and other greenhouse gases to be on par with Canada's typical annual emissions.

• In fact, said Mike Flannigan, a researcher at Thompson Rivers University, the emissions estimates to date are likely underestimating the magnitude of emissions.
• Given that climate change played a key role in setting off this conflagration, the emissions will only serve to worsen global warming, thereby making parts of the globe even more prone to fire in a positive feedback loop.

Threat level: "Climate change is playing a major role," Flannigan said, noting the presence of sprawling and intense high pressure areas — also known as heat domes — that elevated temperatures, caused relative humidity to plummet and turned forests into tinderboxes.

• The atmosphere was so primed for fire this summer that researchers have documented as many as 100 or more towering, fire-generated thunderstorms, known as pyrocumulonimbus clouds.
• These clouds are a telltale sign of extreme fire weather conditions near the ground, and they can transport ash and other emissions into the stratosphere.

• The emissions estimates to date lack an accounting of emissions from smoldering taking place near ground level, and in the boreal forests in northern Canada, in the organic layers of peat and moss, clumps of material that fire scientists call "duff."

The intrigue: According to Turetsky, it won't be until field researchers can explore affected areas that the fire season's true costs in carbon emissions are more fully accounted for.

• She is particularly concerned about the fate of carbon stored within the soils, including the layer of permanently frozen ground known as permafrost.
• Some of the organic material on the ground and just under the surface contains carbon that was stored there as many as thousands of years ago.
• "The atmosphere really is not expecting it back. So when we return old carbon to the atmosphere, that's a true feedback to climate change," she said.
• Another ramification of so much fire in boreal forests is that the cool, wet peatlands that act as a buffer that maintains permafrost gets degraded, allowing for faster permafrost thaw and emissions of still more greenhouse gases.

What they're saying: "The boreal forest is a carbon powerhouse in the global climate system," said Turetsky, warning that it may be starting to lose this status.

• If that happens, "It's going to shift into some kind of other carbon function within the climate … And we don't really know what that's gonna look like."

Go deeper: Canada's wildfires bring skyrocketing carbon emissions

U.S. air quality hit as 1,008 wildfires burn across Canada

Canadian officials warn historic wildfire threat could persist into fall