Homes are sinking and trees are tipping over in Alaska. Mammoth bones are surfacing in the Russian Far East — so many that people have begun selling the tusks as a substitute for elephant ivory. And in 2016, more than 70 people in western Siberia were hospitalized for exposure to anthrax, likely spread from a decades-old reindeer carcass that thawed from frozen ground.
In 2016, meltwater seeped into the entrance tunnel of the Global Seed Vault, a subterranean facility in Arctic Norway nicknamed the Doomsday Vault. There, millions of collected seeds are supposed to stay frozen indefinitely, with little upkeep, a safeguard to restart agriculture should the world’s crops be lost in a large-scale disaster. No seeds were harmed — the water refroze long before reaching the vault — but the breach made the world wonder: Will the Doomsday Vault last until doomsday?
The events are connected, caused by the same phenomenon: They occurred in regions covered in permafrost, ground that should stay frozen throughout the year but is now thawing because of global warming.
Permafrost covers about 25 percent of all ice-free land in the Northern Hemisphere. For millennia, much of this ground has been a cemented mass of soil, rock and ice, along with bits of organisms preserved from decay in a deep freeze.
But as temperatures rise, “the ground’s giving way to mush,” says archaeologist Jeff Rasic, chief of resources for Gates of the Arctic National Park in Alaska. Warming ground leads to erosion, sinking and structural damage. Frozen organisms, including pathogens that can infect living hosts, also thaw.
And the worst is yet to come. Organic matter trapped in permafrost — everything from mammoth carcasses to ancient fruit — contains massive stores of carbon, an estimated 1,500 billion tons, or nearly twice the carbon currently in the atmosphere. As the ground warms, the long-frozen material will decay and release the carbon as greenhouse gases.
“The more carbon we have in the atmosphere, the more warming we have, and that creates a feedback,” says Northern Arizona University ecologist Christina Schädel, who coordinates a global network of scientists studying the impact of permafrost thaw.
As researchers scramble to predict the effects of climate change on permafrost, Arctic people are already witnessing it, right beneath their feet.
Defined as ground — including rock, soil, ice and other organic material — that remains frozen for at least two consecutive years, permafrost covers much of the Northern Hemisphere’s upper latitudes, but it’s not remaining frozen anymore. As global temperatures rise, especially in polar regions, vast amounts of it are thawing, creating a host of problems.
Bring Back the Dead: Reviving Ancient Plants and Viruses
Permafrost is cold, dark, oxygen-free and has a neutral pH — that is, neither acidic nor basic, like water. “It’s really the best place to keep alive something that doesn’t need any kind of metabolic activity,” says Jean Michel Claverie, a microbiologist at Aix-Marseille University in France. That means microbes, seeds and spores, frozen in a dormant state, could awaken with a little warming.
This was proven in 2012, when researchers from the Russian Academy of Sciences sprouted three dozen Silene stenophylla, herby white tundra flowers, from 30,000-year-old fruits. The specimens were recovered from ancient squirrel burrows, 125 feet deep in the permafrost of northeast Russia, according to the study published in Proceedings of the National Academy of Sciences. After sprouting in nutrient-rich test tubes, the seedlings had run-of-the-mill plant lives: They grew into fruit-bearing flowers in plastic pots and soil, resuming normal biological activity after being frozen for 300 centuries.
Seeing the study, Claverie, who researches virus evolution, thought, “If they were able to revive a plant, we should be able to revive a virus.”
Within four years, his team resurrected two never-before-seen viruses from the same 30,000-year-old deposits. Both reawakened in laboratory dishes and infected living amoebas.
Through these experiments, researchers can directly study how viruses and life-forms evolved over time. “I think we can really try to understand better the origin of life,” says Claverie. “Permafrost is important because we can go deeper and find ancestors of those viruses.” Currently, his team is preparing to analyze samples taken from more than 500 feet deep in the permafrost, dated to about 600,000 years ago.
Although the scientists have only worked on amoeba-killing viruses, the research heightens concerns that pathogens infectious to humans will also emerge — outside of the laboratory — as permafrost thaws.
This is already an issue in the Russian Arctic, where anthrax outbreaks in the early 20th century killed an estimated 1.5 million reindeer. Many of these animals, along with infected cattle, are buried in near-surface permafrost — the so-called active layer that thaws in summer and freezes in winter. When warmed, the carcasses release anthrax spores, which readily reactivate into infectious bacteria. The phenomenon likely caused a 2016 outbreak that hospitalized 72 Nenets reindeer herders.
And it’s not just anthrax from rotting reindeer. Cemeteries across permafrost zones of North America and Russia contain victims of smallpox, plague and influenza.
However, Claverie believes there is low risk of a global pandemic from these diseases in permafrost. “If it’s an old known disease like smallpox, it will be sad for the poor people who get it, but it could be OK because it could be recognized quite easily, and you put the people in quarantine.”
He is more concerned about unknown diseases deeper in the permafrost being brought suddenly to the surface by mining and industrial development in the Arctic — prehistoric pathogens, for which we have no defense.
Frozen Heritage: Archaeological Sites Found — and Lost
Permafrost thaw is opening other windows to the past at archaeological sites. “It’s this incredible archive of information,” says Rasic, who works at digs in Arctic Alaska. “Things that should have rotted away a long time ago have been frozen and preserved.”
Perishable items, like basketry, wooden tools and clothing, can be preserved for millennia in permafrost, and show how ancient peoples survived one of the toughest environments on Earth.
For example, at Birnirk, a site in far north Alaska dated to A.D. 600-1300, archaeologists recovered parkas, boots and even baby clothes made from sealskins and polar bear fur — “incredibly high-performing garments out of all natural materials,” says Rasic. “They made fine needles and threads and could sew watertight seams in a time before Gore-Tex and all the high-tech fibers we have now.”
At another Alaskan site, Raven Bluff, bones were so well preserved that Rasic assumed they were a few hundred years old. But results from radiocarbon dating brought a shock: Raven Bluff was inhabited 11,000 years ago. Permafrost sites of this era are key to understanding how Ice Age people migrated from Siberia and settled the Americas.
Permafrost thaw may help archaeologists discover sites because the warming ground leads to erosion, which exposes artifacts, but it’s a double-edged sword. Unless the sites are quickly excavated, the perishable artifacts rot away, and there are not enough Arctic archaeologists to keep pace with the thaw. “We’re resigned to always losing more sites than we can ever address or save, but there’s a real pressure right now to be very efficient with our triage decisions,” Rasic says. “It’s a matter of collecting information before it disappears.”
A Toxic Threat
Permafrost thaw isn’t the only threat: Melting ice sheets bring additional risks.
Last summer, climatologist William Colgan, a researcher for the Geological Survey of Denmark and Greenland, led an expedition of scientists to Camp Century, an abandoned U.S. military base buried in the Greenland Ice Sheet.
“When you get to Camp Century today, it’s totally flat white. There’s nothing showing above the surface. It’s just a pancake, white, ice sheet,” says Colgan.
But 10 stories beneath the surface are the remains of the facility, which in the 1960s spanned more than 100 football fields and housed as many as 200 soldiers from the U.S. Army. One mission was top secret and code-named Project Iceworm: install ballistic missiles under the ice sheet, within range of Russia.
By 1967, the Army had abandoned the project, leaving behind hazardous wastes including sewage, radioactive coolant and carcinogenic industrial chemicals, as well as diesel fuel. Engineers at the time assumed these toxins would be preserved indefinitely under ice.
But the Greenland Ice Sheet is melting, and faster than once projected. From 2007 to 2011, the ice sheet shrunk by about 290 billion tons per year. Compare that with an average loss of 83 billion tons per year from 1900 to 1983.
According to Colgan, the good news is that if countries meet goals laid out in the Paris Agreement and other climate change-fighting guidelines, the site should stay frozen.
The bad news: If current warming trends continue unabated, the toxic wastes will likely begin to melt out of the ice sheet, irreversibly, within 75 years.
To make these predictions, the authors estimated the extent of debris using historical records and maps from the camp. The goal of the 2017 expedition was to set up long-term monitoring of the site.
The scientists couldn’t physically enter Camp Century because decades of snow and ice accumulation have sealed the entrance. “It doesn’t look like there’s any air space left in the tunnel network, so even if we were to dig down to 30 meters to one of the access points, it looks like all the tunnels are just crushed completely shut,” Colgan says.
Instead, the researchers collected ice cores for analysis and installed weather and ice-monitoring devices, which transmit real-time data back to lab headquarters in Copenhagen. Donning cross-country skis, they also towed ice-penetrating radar across the surface to produce more accurate maps of subterranean debris.
The radar data showed that waste is spread about a mile across — double the area expected — and in some spots is at a depth of less than 100 feet.
Despite the extensive spread, Colgan believes the waste could remain trapped in ice. “Whether or not Camp Century becomes a problem has very much to do with our choice of climate pathway as a society,” he says.
Citywide Slump: Life on Shifting Ground
Modern human settlements are also in peril. Permafrost includes ice that is both pervasive — binding soil components together like glue — and concentrated in thick, pure chunks. When gluelike ice melts, the soil becomes mud, causing gradual sinking and erosion. When ice chunks melt, the overlying ground can suddenly collapse.
But buildings can lose structural integrity and become unstable even with modest increases in ground temperature, well before all-out melt. In Alaska alone, the destruction of buildings and infrastructure due to permafrost thaw over the next century could cost more than $2 billion, according to a 2017 study.
Regions affected may seem remote and largely uninhabited to outside eyes, but permafrost lands contain settlements ranging from small villages to industrial cities with populations over 100,000.
Norilsk, Russia, typifies the urban Arctic. Erected in 1935 as a gulag work camp, Norilsk has grown into a nickel mining and smelting center. With 178,800 residents, it’s about the size of Fort Lauderdale, Florida, but similarities end there. Norilsk is one of the world’s northernmost cities and Russia’s most polluted. In December, the sun does not rise, and temperatures dip below minus 20 degrees Fahrenheit.
Like most cities in the Russian Arctic, Norilsk was custom built for permafrost. “The colder the permafrost, the harder or stronger the freezing force that holds foundations,” says Dmitry Streletskiy, a geographer at George Washington University who studies the effect of permafrost thaw on human habitations.
Twentieth-century engineers calculated how much weight foundations could support based on ground temperatures — but those temps have risen by up to 3.6 degrees across Russian permafrost zones in the past three decades. “Those designs were not accounting for such a fast pace of climate change,” says Streletskiy.
In his research, Streletskiy does that accounting. Instead of temperatures from the time of construction, he subs in current climate data. The result of a study he authored in 2012: Foundations across Siberian cities can bear up to 46 percent less load in 2010 than in the 1960s, putting them at risk of collapse.
In Norilsk, hundreds of residential buildings are visibly deformed because of ground thaw, according to the municipal government’s last count in 2015. In other permafrost cities, 10 to 80 percent of structures are in potentially dangerous states.
In some cases, engineers have saved buildings by installing thermosyphons, devices that cool the ground through evaporation and condensation. But “those are pretty much point solutions. You have a couple meters around it where it works,” says Streletskiy. “They can save one building, but they don’t save an entire city.”
While Arctic urbanites grapple with collapsing buildings, traditional coastal villages face total destruction. Over the past five decades, shorelines throughout the Arctic have receded by an average of 1.5 feet annually. Some spots have lost as much as 70 feet in mere hours during violent storms. These Arctic coasts are disappearing due to the combined effects of permafrost thaw, sea level rise and longer summers when the seas are ice-free. In short, more waves are crashing farther onto softer land.
This will mean the end for some communities. A report by the U.S. Army Corps of Engineers concluded that Kivalina, a native Iñupiaq village of 85 homes at the tip of an 8-mile fleck of land in northwest Alaska, will likely be “lost to erosion” within the next decade. Yet the 374 residents remain. Relocation would cost over $95 million and jeopardize their lifestyle, which depends on hunting and fishing coastal resources. They are tethered to the sea, as it consumes their village.
Things That Go Boom: Methane and Mysterious Craters
To the untrained eye, they appear to be meteor impacts: massive, funnel-shaped craters, about 80 feet across and 15 stories deep, that suddenly appear in the Russian tundra. But according to Vladimir Romanovsky, a geophysicist at the University of Alaska who has been monitoring permafrost since the 1970s, “nothing like this was described in any scientific or even not-scientific literature.
“We don’t even have a good name for it yet,” he adds.
At last count, at least nine craters have been confirmed in Yamal, a Russian territory jutting 400 miles north of the Arctic Circle, and neighboring Gydan. Yamal is home to more reindeer than people, as well as Russia’s largest natural gas deposits and the infrastructure to exploit them.
The cause of the craters is uncertain — no one has witnessed one form — but researchers have a hypothesis: Icelike mixtures of methane and water, trapped below and within the permafrost, expand as they warm, heaving up the ground until it erupts.
Supporting this explanation, local reindeer herders reportedly heard loud booms soon before craters were first noticed. At the sites, researchers found explosively high methane concentrations and chunks of earth littering the periphery for thousands of feet. Satellite images from previous years showed the craters were once small hills, bulging from the tundra.
“The fact that they have appeared and weren’t really predicted tells me that there are probably surprises out there that we don’t know about yet, that I’m sure we’ll be seeing soon,” says Ted Schuur, a permafrost researcher at Northern Arizona University.
Although the craters have never been observed before, bulging hills are common in permafrost regions. Systematic surveys, using helicopters and satellites, counted 7,000 such mounds in Yamal and Gydan and 1,350 in the Tuktoyaktuk Peninsula of northwest Canada — at that rate, there could easily be 100,000 such potential time bombs across the Arctic. Most are likely due to frost-heave, when the water in saturated soil freezes and expands, pushing the ground up. But an unknown number could be methane mounds on the verge of eruption.
Fast Forward: Our Carbon Feedback Future
To see what other surprises permafrost thaw will bring, Schuur is speeding up global warming — experimentally — in a dozen plots of permafrost land in the tundra of central Alaska. Since 2008, the plots, each about half a tennis court in size, have been passively heated a few extra degrees: In winter, surrounding fences accumulate an insulating blanket of snow and in summer, the team installs open-topped, greenhouse-like structures made of clear plastic to maximize warming.
“We cause the permafrost to degrade and look at the impact of that, to try to push the tundra into a future state,” Schuur says.
The project is one of many trying to understand the permafrost carbon feedback: The idea that thawing permafrost will allow long-frozen organic matter to be decomposed by soil microbes, which will release greenhouse gases, accelerating global warming.
The feedback was first described in a 2006 Science paper. Yet permafrost carbon has not been included in most climate projections. There are just too many unknowns, including how much carbon is in the permafrost, how easily it could degrade and how quickly it might be released.
To address these questions, experimental heating studies like Schuur’s are being combined with observations of permafrost thawing naturally. Scientists now systematically measure ground temperature and depth of seasonal thaw at hundreds of locations.
In 2015, Schuur and Schädel were co-authors on a landmark paper in Nature that synthesized the available observations and experiments. They concluded that a portion of the permafrost is destined to thaw, which will add about 150 billion tons of carbon to the atmosphere over the next century. That’s comparable to the projected amount contributed by land-use changes such as deforestation, or roughly one-tenth the carbon of fossil fuel emissions.
Beyond this inescapable amount, it’s hard to predict how much more permafrost will thaw — mainly because that depends on human decisions. According to a 2017 study in Nature Climate Change, if countries stick to the Paris Agreement, holding global average temperature to 1.5 to 2 C (2.7 to 3.6 F) above pre-industrial levels, then 55 to 70 percent of permafrost land area could be saved, compared with its near elimination under our current warming trajectory.
Says Schuur, “If we follow the Paris accord, if we reduce our emissions elsewhere, it will just slow everything down and help keep carbon in the ground, in the Arctic where it is now.”
[This article originally appeared in print as "Something Stirs"]