In the mind’s eye, Greenland is anything but a wildfire risk. It’s the great white frozen land of the north, the world’s largest island, gleaming with ice and snow. But due to climate change and its amplified effect near the poles, Greenland is melting and drying out. That means the island once defined by vast glaciers is starting to live up to its colorful name, so it’s now able to host larger wildfires just like any other pristine wilderness. After being in a deep freeze for millennia, there’s a lot to burn under the receding ice:
"These fires appear to be peatland fires, as there are low grass, some shrub, and lots of rocks on the western edge of the Greenland Ice Sheet," Jessica L. McCarty of Miami University told Wildfire Today.
As The New York Times has pointed out, peat is especially vulnerable to the effects of climate change — drying out as temperatures rise — and especially dangerous for exacerbating climate change if it burns. "It's carbon that has accumulated over several thousands of years," one researcher told the paper last year. "If it were to be released, the global CO2 concentration would be much higher."
What is a peatland fire and how does it have anything to do with climate change? Glad you asked. Come below for a brief introduction.
A few years back during an unusual stretch of dry weather in Florida, my neighborhood smelled of smoke and rotting vegetation for several weeks. It was a peat fire. They occur from time to time in places like Florida when boggy areas dry out or get drained for development. Normally, thick wet layers of plant debris build up year after year in swampy regions. Given enough time and pressure, these kind of deposits might one day metamorphose into coal. But dried out swamps are plenty flammable without being squeezed into coal.
The Sunshine State could just as well be called the thunderstorm state, as it damn near rains almost every day. But every now and then, especially in what passes for winter, there might be a period of several weeks without any rain at all. When a once-in-a-decade drought strikes in Florida, wild grass turns brown, palm fronds wither, and fallen logs and drifts of fallen leaves get dry as a bone. And that’s when perfect tinder forms: massive stores of decaying leaves and other plant material mixed with sand that forms the topsoil in much of Florida. If it catches on fire and there’s no rain to put it out, it can spread until it smolders right under your feet for days on end.
Of course Greenland is not Florida—far from it! But climate change is way more pronounced near the poles and it can fuel those subterranean embers in two ways: it directly warms and dries out the ground, and it lengthens the brief Arctic growing season across a broader area. The end result is more flammable material both above and below the surface to feed any fire that might arise.
In the high Arctic, those boggy layers are normally either frozen all year or very moist for a few short weeks during the height of summer. But if that delicate cycle is changed, if the permafrost thaws out and gets dry enough, all it takes is one spark to start a peat fire. Such fires are notoriously difficult to stop. They can spread below the surface like roots, smoldering unseen, occasionally setting fire to trees and buildings from the ground up, until the fuel is finally exhausted or the weather inevitably changes. Presumably, in Greenland and elsewhere up north, the Arctic winter will soon arrive and thoroughly smother any kind of fire under blankets of freezing rain and snow.
But if fires started before, they can start again. There’s a lot of peatland quietly preserved in those frozen plains up north. The hidden loads of dead leaves and stems and grass represent thousands of years of sunlight and billions of tons of CO2 patiently stored away by tiny little chloroplasts toiling away deep inside the cells of green plants since the end of the Pleistocene. Just a few out of control fiery seasons in Greenland could liberate quite a bit of that carbon, and that’s not the half of it. There are also gigatons of methane trapped in the permafrost that would be freed if a meter or two of otherwise rock-hard frozen Arctic tundra were suddenly baked. And it’s not just Greenland: similar hot streaks are plaguing Alaska and the Pacific Northwest this summer.
Global warming doesn’t need a new fiery source of greenhouse gases to pose a danger. But here we have yet another positive feedback loop that may not be fully accounted for in climate models: burning surface material and smoldering peat release more greenhouse gases into the air, contributing to more global warming, which thaws more permafrost, freeing more methane, and igniting more stubborn fires like those dotting Greenland’s interior right now.
If that keeps up for long, Greenland’s climate could become less like the windswept winter wilderness it is now and more like the British Isles. It might really turn green. Which might be great for a few species trying to eke out a bare existence there now. But it would come at the expense of the rest of the planet, including the geographic foundation our modern civilization depends on.