The thawing of permafrost—the long-frozen ground that covers much of Alaska, Canada, and Siberia—could be a climatic time bomb. Or not.
Estimates of the carbon that could be released into the atmosphere from thawing of the frozen soils just beneath the surface of much of Arctic Alaska, Canada, Siberia, and Scandinavia range from 30 to 150 billion tons by 2100. The upper number is roughly equivalent to the cumulative emissions from the US for the next eight decades if its current emissions rate continues.
A newly announced research project aims to pin down estimates of permafrost thaw and its impact on the affected populations. But the war in Ukraine threatens monitoring and data collection in Russia, which is home to most of the world’s permafrost.
Drop in the bucket or major problem?
Climate scientists now say that the Arctic is warming at three to four times the rate of the world as a whole. That’s up to double the rate observed just a decade ago. Thawing permafrost has already led to the collapse of homes, roads, and other infrastructure. A literature review published in Nature Reviews Earth & Environment in January found that permafrost degradation has damaged as much as 80% of buildings in some Siberian cities and 30% of roads in the Tibetan Plateau.
Even with the strongest efforts to reduce global carbon emissions, the climate of northern Europe and most of western Siberia will no longer be cold and dry enough to sustain peat permafrost by 2040, according to one study published in Nature Climate Change in March. Those peatlands collectively contain 24 billion tons of carbon—more than all the carbon stored in Europe’s forests. But the researchers said that increased cuts in emissions could prevent thawing in northern parts of western Siberia, which hold 13.9 billion tons of carbon.
When permafrost thaws, the resulting waterlogged soil and high organic content is “a perfect recipe” for methanogenic microbes, says Lisa Stein, a biologist at the University of Alberta in Canada. If there were a sudden, large release of organic carbon, methane production would outstrip consumption for some period of time, potentially resulting in a catastrophic methane release. In a worst-case scenario, that could precipitate a runaway greenhouse effect, she says. (The authors of the Sixth Assessment Report by the Intergovernmental Panel on Climate Change [IPCC] say that such a catastrophic release is unlikely.)
However, it’s possible that other microbes that naturally consume methane would grow at a comparable pace. “If that happens, we don’t have to worry so much, because it will be a self-controlling situation,” Stein says.
Because so little is known about permafrost thawing, it has largely been omitted from the global climate models that underpin the already-dire climate-warming forecasts of the IPCC, says John Holdren, the former science adviser to President Barack Obama and current codirector of the Arctic Initiative at the Harvard Kennedy School. A lack of monitoring and data on permafrost behavior has led to a broad disparity in estimates of future emissions from thawing and their contribution to Earth’s “carbon budget”—the amount of permissible carbon emissions remaining if global temperatures are to be limited to 1.5 °C or 2 °C above preindustrial levels. “At the low end, it’s a drop in the bucket, and at the high end, it’s a huge bite out of the carbon budget for even 2 degrees, never mind 1.5,” Holdren says.
In April, Harvard, the Woodwell Climate Research Center, the Alaska Institute for Justice, and the Alaska Native Science Commission announced a six-year, $41 million Permafrost Pathways program. Funded by a group of billionaires and philanthropies called the Audacious Project, the initiative aims to improve understanding of permafrost thaw, its potential climate impact, and its prospective consequences for Arctic people and infrastructure. “Permafrost thaw is damaging to buildings, to pipelines, and to roads,” Holdren says. “There will have to be substantial investments made in adaptation and resilience to deal with in-region impacts.”
Geopolitical realities
Because permafrost regions occupy almost 65% of Russia’s landmass, the grant proposal included establishing eight new carbon-flux monitoring stations in Siberia to be equipped with instruments supplied by the Permafrost Pathways collaborators. Those stations would track the flow of carbon dioxide and methane between the land and atmosphere. Two additional stations would be located in northern Canada.
However, the project is in flux because of Russia’s invasion of Ukraine. “There is no question that this will set us back,” Holdren says. “Leaving Russia out of any attempt to understand what is going on across the world in permafrost leaves out a very big part of the problem.”
Scientific cooperation between Russia and Western governments will be off the table for quite some time, Holdren says, but it isn’t clear that all work with Russian scientists on permafrost monitoring needs to halt. “The parameters of what will be allowed and what not still haven’t been entirely worked out. I’m hopeful we will be able to work out ways to do it.” He points to recent guidance issued by the Treasury Department that permits collaborations between US and Russian nongovernmental organizations on issues of global importance.
The Cascade Institute, a Victoria, Canada–based scientific nongovernmental organization, hopes to help facilitate the Canadian portion of the Permafrost Pathways program, says institute director Thomas Homer-Dixon. Cascade had drafted its own grant proposal to establish a separate monitoring network in Canada.
Canada’s permafrost is much shallower than Siberia’s because of its geology of metamorphic rock covered by a thin layer of soil. In parts of Siberia, permafrost can be thousands of meters deep. Yet, says Homer-Dixon, “My guess is if you got a substantial number of stations in Canada, Alaska, and Scandinavia, you could probably find areas that are close enough to what we know are characteristic of the Siberian permafrost that you could do estimates with satellite data.”
Holdren agrees that satellite-based and airborne tools are becoming more capable of contributing to the monitoring—and, importantly, of discriminating between methane and carbon dioxide emissions. Methane is more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere.
Implications and solutions
Ultimately the only way to halt permafrost thaw is for the world to rapidly reduce its greenhouse gas emissions. Still, Cascade will be exploring potential interventions to slow thawing. “We’re not in the business of sitting back and saying the world is circling the drain,” says Homer-Dixon. “Even if they are long shots or crazy ideas, at least we ask the question if anything can be done.”
Peat moss, which thrives in the boggy land that results when permafrost thaws, harbors a rich methane-consuming microbial population, Stein says. Thus, preventing destruction of peat moss and stimulating its growth with the proper nutrients could help keep methane emissions in check.
Another possible mitigation measure, one that has been shown to slow permafrost thaw in Scandinavia, is controlling herds of caribou, says Homer-Dixon. Caribou are voracious eaters of lichen, which reflects more sunlight than does barren ground.
Since permafrost loss is inevitable in the long term, adaptation by Arctic residents to their damaged landscape will be important. “How do you preserve the culture of the people of the north when the tundra is thawing and slumping?” asks Stein.
Reducing uncertainties about permafrost thaw is essential for policymakers to shape global targets for emissions reductions and adaptation measures, says Holdren. But today, policymakers tend to ignore the permafrost issue, says Homer-Dixon, “because it’s so scary. They think that if [thawing] happens, it’s game over.” Scientists who work in the relevant Canadian ministries have told him that the IPCC “knows what’s going on” with permafrost. “That’s BS,” he says. “We don’t know. The real reason they say that they’ve got it covered is they don’t want to think about it.”
