What Is Permafrost? Why Thaw Matters for Climate Change

Permafrost in 2026: The Latest Data

Scientists have measured a change here that matters for the climate. Here is where the research stands.

What Is Permafrost?

Permafrost is a layer of the Earth’s soil that is constantly frozen. The frozen layer can occur at the surface or under a layer of soil that is not frozen. Permafrost is also found under bodies of water, like lakes or oceans. It consists of soil, gravel, rocks, and sand held together with ice throughout the year.

Permafrost covers about 8.8 million square miles of land in the Northern Hemisphere. The thickness of its layers is anywhere from 3 feet to over 3,000 feet. Permafrost forms when groundwater trapped in soil and rocks is exposed to temperatures below freezing most of the year, and it occurs in regions like the Arctic tundra or high altitude mountain regions.

For frozen ground to be considered permafrost, it must remain frozen for two consecutive years. Many regions around the world have ground that freezes for part of the year, but permafrost is unique in that it is frozen even through the summer months.

While two years is the minimum for permafrost consideration, some regions have had frozen ground for hundreds of thousands of years. Scientists discovered the oldest known permafrost in Siberia, which has been frozen for the past 650,000 years.

Where Is Permafrost Found?

Permafrost is present around the globe in different concentrations depending on the region’s geographic features and climate. It can be found in many areas where the average temperature remains cold enough for ice to stay solid all year. Below, we’ll look into where you can find permafrost around the world, including which countries have the most permafrost landscapes.

Permafrost is found in the Northern Hemisphere and the Southern Hemisphere but is more predominant in the northern half of the globe. There is a higher concentration of permafrost in the Northern Hemisphere due to the greater land area found there. The Southern Hemisphere has more oceans and less land that can freeze and become permafrost.

In the Northern Hemisphere, 24% of the land has permafrost underneath it. On the southern half of the globe, permafrost is found in the high alpine regions of Patagonia and New Zealand. It is also found in the 0.3% of Antarctica that is not covered with ice sheets. Scientists believe there may be permafrost beneath the ice sheets, but it is difficult to study because the Antarctic ice sheets are thousands of feet thick in some areas.

Permafrost is found most in Arctic tundra landscapes. Canada, Alaska, Greenland, Siberia, and Eastern Europe are covered in tundra that has high concentrations of ground that is frozen year round. For example, about 85% of Alaska is underlain by permafrost. Russia has more permafrost than any other country, with two thirds of its land area having frozen soil layers that last year round.

High alpine places also have permafrost. Regions where the altitude keeps the average temperature low enough can have ground that remains frozen. Examples of these places include the Tibetan Plateau in Asia and the Colorado Rockies in the United States.

Why Is Permafrost Important?

From playing an essential role in polar ecosystems to slowing the rate at which climate change occurs, permafrost holds a large part in global climate conditions. However, it’s not only the climate that permafrost affects. It also acts as an incredible resource for scientists to understand Earth’s biological history. Plus, it provides a reference point for climate scientists to study and make predictions about global climate trends.

Let’s take a look at how important frozen ground really is.

Protecting Tundra Ecosystems

Permafrost creates the foundation for tundra ecosystems. It contributes to freeze thaw cycles that the plants and animals of the Arctic have come to rely on. Its presence inhibits the growth of many plant species, save for the ones that have evolved to grow in harsh conditions. The permafrost creates a steady and predictable environment for tundra life to flourish. Protecting permafrost can go a long way toward preserving Earth’s biodiversity.

During the warm summer months, the top layer of soil melts, but the permafrost remains beneath and traps water near the surface. The trapped water creates shallow lakes and bogs that teem with life. Migratory birds and insects take advantage of the unique tundra wetlands that form during the summer.

As permafrost thaws due to climate change, the tundra ecosystem is experiencing rapid change. Plant and animal species that are not native to tundra lands have begun to venture further north, creating increased competition in the ecosystem. Plus, the absence of permafrost can cause the landscape to change dramatically, creating land erosion and the disappearance of lakes.

Preventing Global Warming

Permafrost and the tundra landscape it creates is one of Earth’s methods for reducing the amount of carbon in the atmosphere, part of the wider global carbon cycle. Permafrost stops the decay of plant matter, which reduces the amount of greenhouse gases released each year. Permafrost soils hold about 1.5 trillion tonnes of carbon, roughly twice the amount that is currently in the atmosphere.

Dead plant matter in other biomes is consumed by microbes during the process of decay. The byproduct of decay is carbon dioxide and methane released by these microbes. Permafrost shelters plant and animal matter from decay, preventing greenhouse gases from being released.

However, as more permafrost melts, more organic matter is exposed to decay. This means tundra landscapes that once acted as a carbon sink are now acting as carbon contributors in many areas, as NOAA’s Arctic Report Card has documented.

Providing Access to Biological History

Permafrost provides scientists with the opportunity to look into the Earth’s biological past. The frozen layers of sediment preserve plants and animals of the past and give scientists the opportunity to observe specimens that have experienced very little decay. Permafrost does such an excellent job of preventing decay that even DNA has been preserved and collected by scientists in specimen and soil samples.

One of the fascinating preserved ice age animals found in North America is a wolf pup that was completely intact, save for its eyes. Evidence of western camels, arctic hyenas, and scimitar cats has also been found in North America. In Siberia, a cave lion cub about 28,000 years old was found with its whiskers still intact, and a woolly mammoth about 39,000 years old was preserved so well that researchers could draw liquid blood from it.

Presenting Scientists with Climate Data

Another important role permafrost plays is that it provides climatologists a point of reference from which they can make observations about temperature changes in Arctic regions. Because the tundra landscape of the Arctic is so dependent on permafrost, the changes to the landscape are easy to observe as the frozen earth melts away.

The diminishing permafrost allows scientists to gather information on the effects our planet faces due to climate change. From this information, we can learn ways to slow the loss of permafrost and tundra landscapes.

Is Permafrost Melting?

Arctic permafrost is melting due to increasing global temperatures. How much is lost by 2100 depends heavily on how much the world cuts emissions. The IPCC’s 2019 special report on the ocean and cryosphere projected that Arctic permafrost in the top three meters of ground would shrink by 2 to 66% under a low emissions scenario and 30 to 99% under a high emissions scenario. An international team that included University of Alaska Fairbanks researchers found that models point to about 77% of near surface permafrost lost by 2100 under a high emissions pathway. The evidence of permafrost thaw is apparent and includes disappearing lakes and changes to the shape of the landscape.

When permafrost melts away, there is nothing to stop the water draining from the lakes in the region. The lakes that form in the tundra remain full because the permafrost ice under them creates a barrier that water cannot pass through. But as permafrost continues to erode, underground drainages become larger, and scientists have started to observe the disappearance of lakes that, in some cases, are multiple square miles in size.

Other evidence of melting permafrost includes dramatic changes to the landscape. Hillsides have become unstable, and landslides of soil and plants are beginning to give way without the permafrost there to support them. One study in northern Siberia found that disturbed land surfaces increased by more than 300% over about two decades. On Banks Island in the Canadian Arctic, researchers counted about 60 active thaw slumps in 1984 and more than 4,000 by 2013.

The rate at which permafrost melts has been affected by an increase of wildfires in the Arctic, which also add to air pollution and emissions. As the permafrost melts, the plants in the region become drier as surface water levels diminish. Wildfires are then more likely to occur. The wildfires themselves then contribute to the loss of permafrost, adding to the cycle in a feedback loop.

What Are the Three Risks Associated With Permafrost Thaw?

There are a number of risks associated with thawing permafrost. Of all the negative consequences, though, there are three that have the potential to be most damaging to the entire planet.

The first is increasing climate change as more carbon dioxide and methane are released due to organic matter decay. The second is the potential for releasing bacteria and viruses that were frozen long ago and could become active again once thawed. Last, there is evidence to support an increase in heavy metals in the Arctic food chain as a result of the thawing of permafrost.

Let’s look into each of these risks associated with thawing permafrost.

Contributing to Global Warming

Permafrost regions typically have a top layer that melts during the summer months. This layer is known as the active layer and is the part of the land that supports life when it is warm enough. The plants that grow in the active layer eventually die, and the remains end up in the soil.

Unlike other areas of the world, though, these remains are not decomposed because it is too cold for microbes to break down the organic material. So, in areas where there is permafrost, much of the soil has plant matter that is full of carbon, ready to get broken down once it thaws out.

Now that global warming has caused permafrost to melt, all the plant matter in the soil is ready for microbes to begin their decomposition work. As the microbes decompose all the carbon rich matter, they emit carbon dioxide or methane into the atmosphere. Methane traps more heat than carbon dioxide while it lasts, and you can read about what happens to gases in the atmosphere over time. The increase in these greenhouse gases then causes more warming and more permafrost melting, resulting in a feedback loop that isn’t good for the state of permafrost or the global temperature.

Releasing Bacteria and Viruses

As the permafrost gives way, it is like opening up a time capsule to the past. That past can include old viruses and bacteria, including strains that resist antibiotics. As the permafrost melts away, these microbes can enter the water runoff and become active.

In 2023, a French research team revived several ancient viruses from Siberian permafrost samples, including one that had been frozen for about 48,500 years, the oldest virus ever revived. Those viruses infect amoebas, not people or animals, but the researchers noted that the same long term preservation could apply to microbes that do affect humans. As many of these bacteria and viruses are not well studied, there are questions surrounding what the impacts could be if they were introduced into the modern ecosystem.

An anthrax outbreak occurred in Siberia in 2016 on the Yamal Peninsula. It killed roughly 2,000 or more reindeer and a 12 year old boy, and dozens of people were hospitalized. Researchers linked it to an unusually warm summer that thawed an infected reindeer carcass, though others point to lapsed vaccination and large reindeer herds as contributing factors. Either way, it is an example of the risks associated with bacteria and viruses thawing out of permafrost.

Exposing Food Chains to Heavy Metals

Northern permafrost regions hold about 1,656 gigagrams of mercury, roughly 32 million gallons, making them the largest known reservoir of mercury on the planet. That is nearly twice as much mercury as all other soils, the ocean, and the atmosphere combined. About 793 gigagrams of it, more than 15 million gallons, is frozen in the permafrost itself. As the permafrost regions continue to melt, some of this mercury could be released into waterways and eventually the ocean, where it has the potential to contaminate ecosystems around the world. The study did not measure how fast that release is happening.

Mercury can cause health issues in the nervous system and vital organs. If mercury concentrations spike in fish stocks, animals higher up the food chain are likely to become exposed to the metal.

How Can We Stop Permafrost from Thawing?

The most effective way to limit permafrost thaw is for the whole world to take action against climate change. Melting permafrost is a product of global warming, which is a worldwide issue. If the world comes together to fight the changing climate, we can slow the rate at which permafrost is thawing, although some thaw is already underway and cannot be undone on human timescales.

Countries around the world must focus on limiting their carbon footprint by moving away from burning fossil fuels and toward sustainable energy sources. It helps to know where emissions come from, such as the top contributors to CO2 pollution in the US. Options like carbon finance systems incentivize businesses and governments to reduce their annual emissions, and natural carbon removal can help take carbon back out of the air. Putting a dollar figure on the damage this kind of warming causes is what the social cost of carbon tries to do.

It’s not just up to governments, though. Each individual plays a role in slowing climate change. You can take action in your daily life to limit your personal carbon footprint. Remaining conscious of how much energy you use for your home or business goes a long way in reducing emissions. A good place to start is the carbon footprint calculator, which shows where your emissions come from.

You can also look into carbon offsets to address the emissions you cannot yet cut. Offsets fund verified emission reductions or removals through projects elsewhere, and they do not directly protect Arctic permafrost. They work alongside cutting your own emissions, not instead of it. If you want to understand the terms, read about the difference between a carbon offset and a carbon credit, and how to find high quality offsets that meet recognized standards.

FAQ: Permafrost

What is permafrost?

Permafrost is ground, including soil, gravel, rock, and sand held together by ice, that stays frozen for at least two consecutive years. It can sit at the surface or beneath a layer of soil that thaws each summer.

Where is permafrost found?

Mostly in the Northern Hemisphere, where about 24% of land has permafrost beneath it, including Arctic tundra in Canada, Alaska, Greenland, and Siberia and high mountain regions like the Tibetan Plateau and Colorado Rockies. Russia has the most, with about two thirds of its land area.

Is permafrost melting?

Yes. The Arctic’s last 10 years were its 10 warmest on record, and permafrost temperatures reached record highs at nearly half of Alaska’s long term monitoring stations in 2024. How much is lost by 2100 depends on emissions: the IPCC projects 2 to 66% loss of near surface Arctic permafrost under low emissions and 30 to 99% under high emissions.

How much carbon is stored in permafrost?

About 1.5 trillion tonnes of carbon, roughly twice the amount currently in the atmosphere. If it thaws and decays, much of it can be released as carbon dioxide and methane.

Is the Arctic tundra now a source of carbon?

In many areas, yes. NOAA’s 2024 Arctic Report Card found the tundra has shifted from a net carbon sink to a net source over at least the last two decades, driven by permafrost thaw and wildfire. A 2025 study found over 30% of the Arctic and boreal region is now a net carbon source, or 40% when wildfire emissions are included.

What are the main risks of thawing permafrost?

Three stand out: more carbon dioxide and methane entering the atmosphere, exposure to old bacteria and viruses, and release of mercury into waterways and food chains.

Can we stop permafrost from thawing?

Not entirely, because some thaw is already underway, but cutting global greenhouse gas emissions can slow it and limit how much is lost.

Do carbon offsets protect permafrost?

Not directly. Carbon offsets fund verified emission reductions or removals through projects elsewhere, and they work alongside cutting your own emissions, which is the main lever for slowing thaw.

Permafrost Is Deserving of Protection

It’s amazing to think what a pivotal role frozen soil can play in the state of Earth’s climate and global ecosystem. Permafrost, if kept in its proper frozen state, is a huge benefit to the planet and to humankind. It protects delicate tundra ecosystems and keeps large amounts of carbon out of the atmosphere. All the while, it provides scientists the ability to look into Earth’s biological past and draw conclusions about the future of our planet.

It’s worth protecting permafrost to avoid adding to global warming and to limit the release of old microbes and mercury. Cutting emissions is the most direct way to slow thaw, and every bit of avoided warming helps keep more of it frozen.

Learn how Terrapass carbon offsets fund verified emission reductions and removals, see options for businesses, or browse more climate guides on the Terrapass blog.

Sources for the 2026 data:
Arctic Report Card 2024, tundra now a net carbon source (States Newsroom)
High North News, 2024 permafrost temperatures and wildfire emissions
WMO summary of the Arctic Report Card 2025
International Cryosphere Climate Initiative summary of the January 2025 Nature Climate Change study
USGS, Permafrost stores a globally significant amount of mercury (2018)
EGU summary of the IPCC special report on the ocean and cryosphere
University of Alaska Fairbanks, near surface permafrost projections
UNEP 2012 report on permafrost carbon

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