In my upcoming near-future novel “A Diary in the Age of Water”, a Gwich’in colleague of the main character discovers that her entire community, shilakut, perished in a sudden flood in Fort McPherson. They’d been washed away in a flash flood of the Peel River:
Most people think that all that meltwater from the melting permafrost creates more surface water, but it causes increased desiccation. The lakes just drain away. But first comes the flood. When the permafrost beneath a northern lake melts, groundwater flow surges, intensifying the base-flow of a river and causing massive flash floods, like the tragedy of Fort McPherson. Once it drains away, the lake disappears; along with the permafrost, which you could say acts as a seal, keeping the water in a bowl of frozen ground. Flash floods and groundwater flow surges in the north of melting permafrost is a common occurrence now. It’s like a last cataclysm before there’s nothing.
Meantime, today, in Sachs Harbour—an Inuvialuit settlement on Banks Island in the Arctic Archipelago—the graves of the community elders, set upon the permafrost, are sinking, writes Alanna Mitchell in the April 2017 issue of Canadian Wildlife. To the Inuvialuit the permafrost is alive and they feel they are witnessing its death.
Permafrost covers over half of Canada and most of its north. It is essentially a thick subsurface layer of soil that remains frozen throughout the year. Thickness ranges from a few metres to many hundreds of metres, depending on the climate, and efficiently stores carbon as methane or peat. The large carbon pool stored in permafrost represents more carbon than currently exists in all living things. Globally, permafrost contains 1700 billion tons of organic material, built up over thousands of years and slowly degraded under the cold Arctic conditions, and amounting to almost half of all organic material in all soils. Permafrost is an efficient carbon sink, storing four times the carbon that was released to the atmosphere by human activities. Species that thrive in the permafrost habitats are highly adapted to their harsh conditions; these include the shallow roots of Black Spruce; the arctic fox that hunts lemming; the arctic hare that builds grass nests up on rocks instead of burrowing and eats snow when it’s thirsty. Cariboo find food and safe places to have their young in the bogs of the permafrost. Grasses, lichens and shrubs have adapted to the shallow soils of the tundra and, in fact, protect the permafrost from thawing with a blanketing buffer. When a fire or flood or unusually high temperature thaws the permafrost, the boreal forest growing there often get weakened roots and tilt or fall over; ecologists call this a drunken forest. When permafrost thaws under a lake, microbes decompose organic material and convert it to methane.
Aside from the scenario I described in my book above, other deleterious effects of thawing permafrost trouble scientists. Here are two:
- Melting permafrost releases stored methane into the atmosphere: methane is 20 times more efficient in trapping heat than carbon dioxide. Its release into the atmosphere will contribute that much more to global warming.
- Melted permafrost dramatically changes water chemistry: the melt percolates into once-frozen soil and picks up once locked minerals in great pulses during times when such fluxes do not normally occur. Sulphate and phorphorus export into the Arctic Sea have increased dramatically. According to hydrologist Ryan Toohey, higher sulphates may put toxic mercury into circulation through microbial activity, potentially adversely affecting the Bering Sea and Arctic Ocean in ways we can only guess.
The Arctic Ocean, already stressed, is a thermostat for the planet. It also helps control the ocean currents and our climate. What a significantly warmer Arctic Ocean may well herald a modern “pliocene epoch” and associated sixth age of extinction in an age of acceleration some call the entrance to the Anthropocene Epoch. The National Geographic recently reported that carbon dioxide in the atmosphere of Earth exceeded 400 parts per million for the first time in 55 years of measurement—and probably more than 3 million years of Earth history. The last time this concentration of greenhouse gas occurred, horses and camels lived in the high Arctic and seas were at least 30 feet higher.
Melting permafrost is a quiet sleeper in the climate change procession. The effects that the thaw exerts is masked by the pristine natural setting that hides the perturbations roiling beneath to the casual observer. Yet, at the microscopic level, in the chemistry of the water and in the change in the atmosphere, a time bomb is ticking.