Why is this important?
Permafrost is soil that has been frozen for at least two years’ time, occurring predominantly in high latitudes and comprising 24 percent of the land in the northern hemisphere. The upper layer, also known as the active layer, will sometimes thaw in the summer. In recent years, this active layer has been getting larger.
So, more permafrost is melting. This can cause physical changes to the land, such as erosion, disappearing lakes, land slides and shifts in local vegetation. It also triggers a shift in the atmosphere, as one-third of the planet’s soil carbon is stored in the frozen organic matter of the arctic tundra.
Two facts have climate scientists worried. One, Since the 1980s, the arctic has been warming at twice the global rate; and two, the planet’s permafrost contains more carbon than is already in the atmosphere.
“There’s so much carbon stored in northern permafrost soils that even if, say, 10 percent of that carbon is released through the processes we studied, it would still have a big impact,” said Rose Cory, an aquatic geochemist at the University of Michigan. According to Cory, a “conservative” scenario of permafrost melt would add more carbon dioxide to the atmosphere than all current man-made emissions.
“What everyone’s really concerned about is how all this permafrost carbon is going to decompose,” she says. “If all of that gets turned into carbon dioxide, then we’ll more than double the amount of carbon dioxide in the atmosphere.”
From 2011 to 2013, Cory and a team of scientists took water samples from 135 lakes and 73 rivers around the Kuparuk River basin in Alaska’s North Slope to test how much floating soil carbon was being oxidized into CO2 and how much was being absorbed into the water. Her team published their findings last month in the journal Science.
Cory’s team found that 45 percent of the soil carbon was remaining in the water. Unfortunately, more than half of it (55 percent) is being converted into CO2.
“Some have speculated that all the permafrost soil carbon would be rapidly released to the atmosphere as carbon dioxide once it flushed into rivers and lakes,” said Cory. “I think it’s encouraging that not all of this carbon that’s coming out of the soil gets turned into carbon dioxide. It’s producing this stuff that’s going to get washed from permafrost, which is one freezer, into the Arctic Ocean, which you can think of as another freezer.”
In terms of how much permafrost will alter climate change, here’s the x factor:
According to the Weather Underground, “climate models do not incorporate the effects of methane released from melting permafrost, which means even the most extreme warming scenarios we’ve come up with might not be enough. A spike in atmospheric methane concentration could set off catastrophic global warming.”
In moist areas, permafrost contains more methane, a greenhouse gas that is 20-25 times more potent than carbon dioxide in terms of warming the atmosphere. Rising temperatures are believed to be the cause behind recent upwells of methane occurring around Siberian lakes. The same phenomenon is being observed in both Canadian and Swedish permafrost and peatland regions.