Fires so intense that they consume millions of acres of trees and scorch the soil on the forest floor have become the kind of extreme disruptors that are remaking the boreal forest and transforming its role as one of the world’s great protectors against global warming. A new NASA study aims to unravel the ways changes in boreal forests affect climate.
The Suomi-NPP satellite captured this image of active fires near Fort McMurray, Canada, in May 2016. Photograph by NASA Earth Observatory
By Laura Parker PUBLISHED June 23, 2016
A monster forest fire that began in early May is still burning in Canada’s vast, isolated north woods. That may seem of little consequence to anyone other than the 88,000 residents of Fort McMurray forced to flee as the blaze swept into the northern Alberta city. Yet large fires like these matter immensely to the rest of the planet. Fires so intense that they consume millions of acres of trees and scorch the soil on the forest floor have become the kind of extreme disruptors that are remaking the boreal forest and transforming its role as one of the world’s great protectors against global warming.
The boreal, which takes its name from Boreas, the Greek god of the North Wind, encircles the top of the globe in North America and Eurasia. Half lies in Siberia, another third in Canada, and the rest in Alaska and Scandinavia. It is Earth’s single largest land habitat, and it stores about 30 percent of the carbon found on the planet’s surfaces—more than any other terrestrial ecosystem. The forest also provides refuge for animals and birds as they relocate from southern habitats that have become too warm….
Now, as forest fires become more intense and frequent, they are creating a similar cycle. Large fires are not only killing all the trees, they are burning through the peat, the rich organic soil on the forest floor that serves as a large reservoir for carbon. “The warmer the Earth gets, the more fire we get, and the more fire we get, the more greenhouse gases we get,” says Mike Flannigan, director of the Western Partnership for Wildland Fire Science at the University of Alberta in Edmonton. Conditions are ripe for more frequent fires in multiple ways. For every degree of global warming, the forest needs a 15 percent increase in precipitation to compensate for the increased drying caused by warming, according to a recent study. Instead, forests are getting less rain, not more.
Scientists also have found that every degree of warming sets off a 12 percent increase in lightning activity, Flannigan says. In the woods, lightning means more forest fires. Fires in Canada’s huge, largely unpopulated forest often burn for months, and are extinguished by the first snow of autumn. Last summer, fires in the Northwest Territories burned more than 3.4 million acres (1.375 million hectares)—an area the size of Maryland….