Permafrost Collapse Is Already Releasing Carbon. Scientists Misjudged the Timeline.

Katey Walter Anthony stood on the frozen surface of a thermokarst lake in central Alaska in March 2025, holding a lighter. When she punctured the ice with an auger, methane bubbled upward from the sediment below. She lowered the flame. The gas ignited in a column of fire three feet high. She had performed this demonstration hundreds of times over two decades of studying Arctic lakes, but what unsettled her this time was the location. Five years earlier, this had been solid tundra.

Walter Anthony, an ecologist at the University of Alaska Fairbanks, studies what happens when permafrost—ground that has remained frozen for at least two consecutive years—thaws. Across the Arctic, permafrost contains an estimated 1,600 billion metric tons of organic carbon, roughly twice the amount currently in Earth's atmosphere. When it thaws, microbes decompose that organic matter, releasing carbon dioxide and methane. The question scientists have wrestled with is not whether this will happen, but when, and how fast.

The answer, according to research published in Nature Geoscience in February 2026, is: it is happening now, and faster than the models predicted. The study, led by a consortium of researchers from institutions in the United States, Russia, Canada, and Sweden, synthesized fifteen years of ground measurements, satellite data, and atmospheric monitoring. Their conclusion overturns a comfortable assumption that guided climate policy for a generation.

What the Ground Told Them

The team measured carbon emissions from 179 sites across the Arctic permafrost zone, from Alaska to Siberia. They drilled cores, installed flux towers, and flew aircraft equipped with atmospheric sensors to measure methane and CO₂ concentrations. What they found was a permafrost region already emitting a net 300 million metric tons of carbon per year—equivalent to the annual emissions of Spain.

The IPCC's Sixth Assessment Report, published in 2021, projected that large-scale permafrost carbon release would not begin until mid-century under most warming scenarios. The mechanism would be gradual: rising air temperatures would slowly deepen the active layer—the top portion of soil that thaws each summer—and over decades, the thaw would penetrate deeper, exposing more carbon to microbial decomposition.

The thing is, permafrost does not thaw evenly. It collapses.

Permafrost is not solid earth. It is a matrix of soil, rock, and ice. In many regions, ice constitutes up to 80 percent of the volume. When that ice melts, the ground subsides, sometimes catastrophically. The surface caves in, forming lakes, ponds, and wetlands. This process, called thermokarst, creates anaerobic conditions perfect for methanogenic bacteria—microbes that produce methane, a greenhouse gas 28 times more potent than carbon dioxide over a century.

Ted Schuur, a permafrost ecologist at Northern Arizona University and a co-author of the Nature Geoscience study, described the implications this way: "We built our climate models on the assumption of gradual thaw. But across huge stretches of the Arctic, we are seeing abrupt thaw. And abrupt thaw was missing from the carbon budget."

The Feedback No One Wanted

Here is what this means. Carbon emissions from human activity warm the planet. That warming thaws permafrost. Thawing permafrost releases more carbon, which accelerates warming, which thaws more permafrost. This is a positive feedback loop, and once it begins, it does not require additional human input to continue.

The 2026 study estimates that if current warming trends continue, permafrost emissions could add the equivalent of 0.1 to 0.2 degrees Celsius of additional warming by 2100. That may sound small. But the Paris Agreement aims to limit warming to 1.5 degrees Celsius above pre-industrial levels. The world has already warmed by approximately 1.2 degrees. The difference between 1.5 and 1.7 degrees is not academic—it is the difference between manageable disruption and compounding crises in agriculture, water supply, and sea-level rise.

What makes permafrost emissions particularly insidious is their invisibility in policy frameworks. The Paris Agreement and national climate pledges focus almost entirely on anthropogenic emissions—those from fossil fuels, agriculture, and land use. Natural feedback loops, including permafrost thaw, are mentioned in IPCC reports but remain outside the accounting systems that governments use to track progress.

What Scientists Disagree About

Not all permafrost researchers agree on the severity or pace of the feedback. Some argue that the new findings overstate the risk by focusing on the most vulnerable regions—those with high ice content and a history of thermokarst formation—and extrapolating those conditions too broadly.

Guido Grosse, head of the permafrost research section at the Alfred Wegener Institute in Germany, points out that some permafrost regions are stabilized by bedrock or have lower ice content, making them less prone to collapse. "There is enormous spatial heterogeneity," he said in an interview with Nature in March 2026. "We cannot assume that what happens in central Alaska will happen identically in the Yamal Peninsula or northern Canada."

Others dispute the methane measurements. Methane emissions are notoriously difficult to quantify because they are spatially variable and episodic—a single thermokarst lake can emit bursts of methane for weeks and then fall silent. Euan Nisbet, a methane researcher at Royal Holloway, University of London, cautioned in a February commentary that while the trend is clear, the magnitude remains uncertain. "We are still learning how to measure this at scale," he wrote. "The error bars are large."

What No One Knows Yet

The critical unknown is whether permafrost ecosystems can adapt. Some researchers hypothesize that as the Arctic warms, increased plant growth—particularly by shrubs and grasses—could offset some carbon losses by absorbing CO₂ through photosynthesis. This is called the "greening Arctic" hypothesis, and satellite imagery does show expanding vegetation across parts of Alaska and Siberia.

But the 2026 study found that even in regions with robust plant growth, the carbon uptake does not come close to balancing the emissions from thaw. The reason is depth. Plants sequester carbon in living biomass and shallow soils. Thawing permafrost releases carbon that has been locked away for millennia, often from depths of several meters. The new carbon entering the system vastly exceeds what plants can absorb on annual timescales.

Another unknown is the role of wildfire. Across Siberia, Canada, and Alaska, wildfires are burning with unprecedented frequency and intensity. Fire removes the insulating layer of vegetation and organic soil, exposing permafrost to summer heat. In some cases, this accelerates thaw by decades. In 2021, fires in Siberia's Sakha Republic burned more than 19 million hectares, much of it underlain by permafrost. Post-fire monitoring by Russian and international teams found active-layer deepening of up to 50 centimeters within two years.

What This Means for the Climate Budget

The IPCC calculates a global "carbon budget"—the total amount of CO₂ humanity can emit while still having a reasonable chance of staying below a given temperature threshold. For a 50 percent chance of limiting warming to 1.5 degrees, that budget is approximately 500 billion metric tons of CO₂, starting from 2020.

At current emission rates of about 40 billion tons per year, the budget will be exhausted by the early 2030s. But that budget assumed permafrost emissions would remain negligible until mid-century. The new data suggests the budget is smaller than we thought—and shrinking faster.

Susan Natali, Arctic program director at the Woodwell Climate Research Center in Massachusetts, argues that permafrost must be incorporated into national climate strategies. "We treat permafrost like it is someone else's problem," she said. "But it is a global emission source that will undermine every climate commitment unless we account for it."

There are no easy policy levers for permafrost. Unlike coal plants or car fleets, you cannot regulate it or replace it with a cleaner alternative. The only intervention is to limit warming itself—which requires rapid, sustained reductions in fossil fuel emissions globally. That is the uncomfortable circularity: permafrost thaw makes meeting climate targets harder, but meeting those targets is the only way to slow the thaw.

The Question They Cannot Answer Yet

Back in Alaska, Katey Walter Anthony continues her surveys. She now tracks more than 300 thermokarst lakes, revisiting each one annually to measure methane flux. What she wants to know—what all permafrost scientists want to know—is whether there is a tipping point beyond which the thaw becomes self-perpetuating, independent of future human emissions.

Some models suggest such a threshold could exist around 2 degrees of warming. Others argue that the feedback, while serious, remains responsive to mitigation efforts well beyond that point. The data is still too sparse, the regional variation too great, to say with certainty.

What is certain is this: the Arctic is no longer a distant early-warning system. It is an active participant in the climate crisis, and it is accelerating the very phenomenon scientists have spent decades trying to prevent. The ground beneath the tundra is shifting. And once permafrost carbon enters the atmosphere, there is no putting it back.