Scientists reached this and several other stark conclusions in six papers that the journal published Tuesday focusing on the fate of the warming permafrost — the continuously frozen grounds that are, as one of the papers described it, “the foundation of the Arctic tundra ecosystems.” The papers were reviews and syntheses of research by groups of scientists in several countries around the polar region.
Atmospheric temperatures in parts of the Arctic have risen by as much as 4 degrees Celsius over preindustrial times, according to an analysis by The Washington Post. That rise — more than triple the global average — stems largely from humans burning fossil fuels.
“Permafrost is basically a reflection of everything that’s happening on top of it,” said Dmitry Streletskiy, an associate professor of geography at George Washington University and one of the authors of the paper on the impacts of changing permafrost on infrastructure. “If you have warmer climates, permafrost will reflect that.”
Another paper reported that underground temperatures in colder permafrost areas — places such as the high-altitude Arctic that have temperatures less than minus-2 degrees Celsius (28 degrees Fahrenheit) — were warming at faster rates, up to about 1 degree Celsius per decade. In comparison, it took the planet more than a century to warm 1 degree Celsius.
“Simulations unanimously indicate that warming and thawing of permafrost will continue in response to climate change and potentially accelerate,” the study said, noting that there was substantial variation in the amount and timing of the predicted changes based on various climate scenarios.
Permafrost covers about 5 million to 7 million square miles in the Arctic and stores nearly 1.9 trillion tons of frozen and thawing carbon, one of the studies noted. As it warms and becomes more unstable, it not only threatens the human-made structures, but the melting releases carbon into the atmosphere that has been locked in ice for millennia, further exacerbating climate change.
Merritt R. Turetsky, one of the authors of a paper about carbon emissions in the Arctic, said it has long been known that permafrost was going to thaw in response to global warming.
“What’s kind of shocking, or what is becoming more clear to us as we amalgamate and synthesize more data, is there are some regions that are changing much more quickly than that global average,” said Turetsky, director of the Institute of Arctic and Alpine Research at the University of Colorado at Boulder. “And these areas also store the most carbon.”
Turetsky cited places such as the Peel Plateau in northwestern Canada or around Yakutsk, a city in eastern Siberia, as examples. What are known as yedoma soils — permafrost rich in carbon and ice — can be “very vulnerable to collapse.”
“Roads, pipelines, houses buckle,” she said. “People can’t travel across the land the way that they have for generations past because the land becomes much more unstable.”
Streletskiy said the impact on infrastructure is particularly serious in Russia, which has more cities and towns situated on permafrost than other countries. His and his colleagues’ paper noted that nearly 90 percent of the population in Arctic permafrost areas is located in Russia. In one city cited in the paper, Vorkuta, an estimated 80 percent of buildings had some deformations because of the changing permafrost.
“It starts with micro-cracks, and then those cracks grow, and then some parts of the building start to subside faster than others,” Streletskiy said. “At this point, you can think about, ‘Okay, should I do something to refreeze it back? Should I do something to adapt? ... Or do I need to abandon the building and move somewhere else?’ ”
Melting permafrost caused a major oil spill in 2020 in the Russian city of Norilsk, when a fuel tank ruptured and leaked tens of thousands of tons of diesel fuel into a river.
In the United States, Alaskans have long faced challenges posed by warming permafrost. Thawing of permafrost leads to increased coastal erosion, and some coastal residents in Alaska have been forced to relocate as land has washed away. Several of those communities are “imminently threatened,” said Rick Thoman, a climate specialist at the International Arctic Research Center at the University of Alaska at Fairbanks.
“They are one storm away, when everything goes wrong, or all the ingredients come together, those places could be uninhabitable,” said Thoman, who was not involved with the journal articles.
While technology exists to siphon heat away from buildings, roads and pipelines to try to keep the ground cold, it can be very expensive to apply it on a large scale. Thoman noted that more than half of Alaskan communities and nearly 80 percent of state-maintained roads are on ground that has permafrost either continuously or in patches. Even mundane fixes such as road repairs get costly when repeated year after year.
“You’re spending a lot of money just to stand still,” Thoman said. “Through the course of the 21st century, this is going to be a very expensive problem for Alaska and all of the Arctic.”
Unlike glaciers or icebergs, permafrost can be hard to measure because it’s underground. To study warming, scientists bore holes into the ground to depths of about 65 to 100 feet and insert sensors that can monitor temperatures at different depths. In Canada, where Sharon Smith works as a permafrost research scientist with the government’s Geological Survey of Canada, there are more than 100 of these underground monitoring sites taking temperature readings, she said.
“Everywhere we do see some kind of warming,” Smith said. “It may be very slow; it may be much greater.”
The variation depends on many factors, such as vegetation and snow cover — snow insulates the ground from the changes in air temperature — as well as the type and thickness of organic layer on the surface.
Smith and her colleagues’ results, which she said were also included in the latest report from the U.N. Intergovernmental Panel on Climate Change, found that in warmer permafrost areas, the rates of warming were lower, typically less than 0.3 degrees Celsius per decade.
“The reason for that is you’re starting to get closer and closer to zero degrees, so the energy doesn’t go into actually raising the temperature anymore. It goes into melting any ice that’s in the ground,” Smith said.
For colder permafrost, which can be lower than minus-10 degrees Celsius, the temperature increases deep in the ground have been rising faster, up to about 1 degree Celsius per decade.
The study also notes that the highest temperatures of permafrost in the instrumental record — spanning more than three decades at some sites — “were recorded in 2018-2019 at most sites in Arctic and sub-Arctic regions.”
Turetsky, the University of Colorado at Boulder professor, focuses her research on places in Canada and Alaska where the boreal forest meets the sub-Arctic, at the southern reaches of that region’s permafrost. In these places, she has witnessed permafrost disappear because of human-driven climate change during her 30-year career.
“I am writing a eulogy for the ecosystem that I love,” she said. “The permafrost has been there for thousands of years in some places, and it will never come back.”