Melting permafrost is an ominous sign of climate change that we rarely see. We’re all familiar with the visuals that commonly illustrate its disastrous effects: footage of wildfires, landslides from melting glaciers, melting polar ice caps fracturing into the Arctic Ocean, emaciated polar bears stranded on blocks of ice. Visceral imagery like this haunts us and helps raise public awareness about global warming. 

But there are other ominous signs of climate change that most of us don’t see: massive lakes disappearing, lush forests turning into wetlands, collapsed bridges and sagging buildings. These are the manifestations of thawing of the Arctic permafrost, a layer of underground soil, rocks, or sediment at high altitude or latitudes that remains frozen throughout the year. It acts as a load-bearing foundation for the ground above it. And without it, the surface becomes unstable, causing immense damage to infrastructure like bridges and buildings, homes and roads, along with geological formations and forests.

For a brief video primer on this topic, check out this video: Permafrost – what is it?

For a more detailed analysis, Arctic ecologist Mark J. Lara recently wrote a piece for The Conversation entitled, “Thawing permafrost is roiling the Arctic landscape, driven by a hidden world of changes beneath the surface as the climate warms.” It’s an informative account of just how massive this issue is, considering that about a quarter of the Northern Hemisphere is made up of permafrost (primarily in Canada, Russia and Alaska). This is a permanent (at least until recently) layer of ice that, in normal conditions, remains frozen throughout the hottest of summers.

Gullies created by melting permafrost drain a lake in the Arctic Coastal Plain of northern Alaska. Christian Andresen and Mark J. Lara, CC BY-ND
NASA Earth Observatory map by Joshua Stevens, using data from the National Snow and Ice Data Center.

One of the most worrisome aspects of thawing permafrost is invisible to the naked eye; it’s a feedback loop that Lara describes in which the melting permafrost revives ancient microbes that consume the thawed organic matter and release greenhouse gasses into the atmosphere; namely, carbon dioxide and methane. And even though the permafrost makes up a minority of the earth’s surface, it’s estimated that this frozen soil accounts for nearly 50% of the earth’s organic carbon, which reportedly is double the amount of carbon in the earth’s atmosphere. By some estimates, at that rate this could increase the release of carbon into the atmosphere by 12-fold by the end of the century.

See also: Carbon Sequestration: Its Value, Impact and Viability

The most astounding evidence of what’s taking place underground is the disappearance of large bodies of water in very short periods of time. In those cases, when the water suddenly leaks into the permafrost that had been holding it in place for millennia. The draining of these lakes has a catastrophic effect on local ecosystems, affecting humans and animals alike. Even if we could miraculously stop global warming and somehow re-freeze the permafrost, that water is gone for good. And in the meantime, an increasing number of wildfires are speeding up the thawing of permafrost in Arctic regions. 

Image of lake drained by permafrost melt.
Gullies created by thawing soil drain a lake in the Arctic Coastal Plain of northern Alaska. Christian Andresen and Mark J. Lara, CC BY-ND

In his article, Lara leaves open the question of exactly how bad this problem is, since, aside from the evidence so far—mutilated landscapes, ruined infrastructure and greenhouse gas emissions—scientists haven’t yet determined the precise consequences of melting permafrost. This seems like a conservative conclusion to an admittedly discouraging report on the effects of global warming.

There are, however, some solutions on the horizon. What Lara doesn’t delve into are some of the efforts of local scientists who are trying to find ways to mitigate some of these problems. Up next in our series

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