Fire on Ice: Arctic wildfires are the new symptom of a warming planet

By Aparna Nathan

Last summer, satellite cameras captured a strange image: a shroud of smoke hovering over the Arctic. But beneath these still, swirling clouds, towers of flames punctuated the bleak expanses. In short, the Arctic was on fire.

The summer of 2019 saw record-breaking blazes emerge throughout the dry polar desert—known as tundra— and the surrounding forests. Arctic wildfires aren’t new, but they had never before consumed such a large area so far north or raged for so long. In just two months, there were over 100 intense wildfires spanning Alaska, Siberia, Canada, and Greenland. Some were as big as 100,000 soccer fields, and in Siberia, they burned for over 3 months, during which they consumed almost 10 million acres of forest.

As we enter the 2020 wildfire season in the Northern Hemisphere, we need to think beyond fires in arid California. Now, Arctic wildfires are another critical hotspot. These areas are remote, allowing the fires to burn indefinitely without threatening human activity, but they are especially dangerous because the Arctic holds some of the biggest carbon stores anywhere on the planet. Burning this carbon is like running a massive engine on raw coal: it releases tremendous amounts of particles and greenhouse gases into the atmosphere that can affect the whole planet.

Anatomy of an Arctic wildfire

To start a fire, you need two main ingredients (other than oxygen): a fuel to burn, and an ignition source to turn up the heat. The Arctic might not seem like an intuitive place to find either of these, but you have to look beyond (and under) the ice. What we traditionally think of as the Arctic is considered a tundra biome. This is a cold, dry desert environment with few plants on the surface, other than shrubs and mosses. If you look underground, though, there are also hidden treasures in the permafrost (a layer of soil and water mixed and frozen together). One key element is peat, thousands-of-years-old semi-decomposed organic matter rich in carbon, maintained by a unique moss coating. The moss can take up lots of water—26 times its weight—and forms a coating over the peat layer that is crucial for keeping the peat from fully decaying and releasing its carbon.

Now, take this frigid landscape that usually hovers around 32 degrees Fahrenheit and turn up the temperature by 10 degrees, which is how much some parts of the Arctic have warmed over the last 25 years. Compared to the rest of the planet, the Arctic is warming twice as fast, and as it gets hotter, it also gets drier, causing the soil—especially the peatlands, and their hydrating coat of sphagnum moss—to lose its moisture. The same drying process happens in the boreal forest, or taiga, that encircles the Arctic tundra. These vast, dense forests are filled with hardy trees—like pines and spruces—and even more carbon-rich peatlands. These forests contain 50% of the planet’s soil carbon stores—equal to the amount of carbon in the atmosphere. Beyond natural forces, human industries like lumber and mining are also siphoning the water resources of the northern forests and tundra, intensifying the land’s dehydration.


SITNBoston



Categories: Arctic, Canada, Climate change, Climate science, Ecology, Environment, Greenland, Russia, Science, Top stories, World news

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