The Dangers Of Permafrost Thaw

The Dangers of Permafrost Thaw

By Anne Rose Muiruri

What Is Permafrost?

Permafrost is any sort of frozen ground, ranging from soil to sediment to rock, that has remained frozen for at least two years and as long as hundreds of thousands of years. It can range in depth from a few feet to more than a mile beneath the earth’s surface, covering huge regions like the Arctic tundra or a single, isolated point like an alpine permafrost mountaintop.

Microbial Breakdown

Microbes that breakdown the carcasses of plants and animals release carbon dioxide, methane, and other global warming gases into the air. A deep freeze successfully halts that process, preserving organisms as well as the gases they would otherwise release underground in the permafrost. The microbial decomposition of those organic materials—and the emission of greenhouse gases—restarts when frozen soil thaws.

Methane Emissions

Permafrost is one of the earth’s major storehouses of global warming gases, containing thousands of years of life, from human bodies to the bodies of woolly mammoths. Indeed, permafrost in the Arctic is thought to contain roughly twice as much carbon as is currently in the atmosphere, as well as a significant amount of methane, a potent greenhouse gas that traps more than 80 times more heat on the globe than carbon. However, as the earth warms, these stores may be jeopardized. The amount of carbon and methane released by thawing permafrost varies, but one study estimates that up to 92 billion tons of carbon could be released between now and 2100. To put it in context, that’s approximately 20% of all global carbon emissions since the Industrial Revolution began.

From Sink To Source

However, the problem does not end there. Looking forward, as thawing permafrost releases more of its massive supply of greenhouse gases into the atmosphere, global warming intensifies, melting even more carbon- and methane-emitting permafrost, an unstoppable feedback loop is likely to be triggered, transforming the Arctic from a carbon sink to a carbon source.

Mercury Release

Permafrost traps a variety of contaminants in addition to carbon and methane.  In the Arctic, permafrost is a large reservoir of natural mercury, a deadly neurotoxin, according to a recent study. Permafrost soils are believed to contain 15 million gallons of mercury, which is approximately twice the amount of mercury found in the ocean, atmosphere, and all other soils combined. However, once released, mercury may spread through water and air, potentially contaminating ecosystems and food supplies.

Infrastructure In Shambles

Cities in northern Russia are literally collapsing. Roads in Alaska are transforming into rollercoasters. When subsurface water freezes, it expands, causing the ground to bulge. When water thaws, the ground compresses, causing the earth to split or cave in, as potholes do in the spring. The permafrost zone is home to some 35 million people who live in towns and cities built on top of what was formerly considered permanently frozen ground. However, as the solid earth beneath their feet begins to sag, the infrastructure on which these communities rely becomes increasingly insecure.

Collapsing Oil And Gas Infrastructure

Each year, vanishing permafrost is anticipated to cost the Canadian Northwestern Territories tens of millions of dollars in public infrastructure damage. One research estimates that the cost of rebuilding public infrastructure in Alaska, such as roads, train lines, buildings, and airports, destroyed by thawing permafrost and other climate-related variables, could reach $5.5 billion by the end of the century. Meanwhile, the fossil fuel sector continues to accelerate climate change by contributing to global warming which in turn fuels the melting of permafrost. There is a growing likelihood that the industry’s own Arctic-based energy infrastructure may fail. If that happens, local ecosystems will be endangered with oil and gas leaks.

Altered Landscapes

Permafrost thawing affects natural ecosystems in a variety of ways. It can result in thermokarsts, sagging earth, and shallow ponds characterized by “drunken forests” of crooked trees. Thermokarst describes the uneven ground that results when soils collapse and settle unevenly after permafrost degrades and thaws. These events can result in ditches and gullies hundreds of feet across or long, and tens of feet deep. Rising temperatures cause the ice structures in permafrost ground to melt. That soil that was once frozen is more vulnerable to landslides and erosion, especially around coasts. As this softened soil erodes, it can introduce new material into waterways, altering river and stream flow, degrading water quality (especially by introducing carbon), and posing a serious threat to aquatic animals.

Rising Sea Levels

Wetlands deteriorate as permafrost melts, as water descends deeper below without a frozen buffer to keep it in place. This can result in drier terrain, which is more vulnerable to wildfires, exposing even more permafrost to heat. Sea level rise can be aided by the loss of permafrost. Indeed, if all of the world’s permafrost thaws, sea levels might rise by four inches, doubling the risk of flooding in areas like San Francisco, Seattle, and Los Angeles.

Ancient Bacteria Survives

Permafrost can trap—and preserve—ancient bacteria in the same way it traps carbon and other greenhouse gases. Some bacteria and viruses are thought to be able to sleep for thousands of years in the cold, dark confines of permafrost before awakening when the ground warms. As terrifying as the idea of “zombie” infections may sound, uncertainties remain regarding how serious a threat there is from these ancient microorganisms. The potential hazard was highlighted by a 2016 anthrax epidemic in Siberia, which was linked to a decades-old reindeer carcass infested with the anthrax bacteria and exposed by thawing permafrost.

Expanding The Artic 

However, when it comes to illnesses like smallpox and the 1918 Spanish flu, which are known to exist in the frozen tundra and in mass graves of those who died from the sickness, scientists are unsure how likely these infections are to trigger epidemics. However, expanding the Arctic—and excavating millions of tons of permafrost to mine for valuable metals and petroleum—will increase human interaction with thawed, ancient, and possibly zombie germs. The scientists are sounding the alarm, but like so many things in this world, the current response is, “just ignore it.”

 

References

Vonk, Jorien E., et al. “Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems.” Biogeosciences 12.23 (2015): 7129-7167.

Schuur, Edward AG, and Michelle C. Mack. “Ecological response to permafrost thaw and consequences for local and global ecosystem services.” Annual Review of Ecology, Evolution, and Systematics 49 (2018): 279-301.