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The Arctic landscape is being flooded by permafrost thawing, driven by a hidden world that changes as the climate warms.

The Arctic landscape is being flooded by permafrost thawing, driven by a hidden world that changes as the climate warms.

Illustration of a thermokarst landscape showing permafrost, ice wedges, polygons, erosion, lake drainable and fires

Strange things are happening in the Arctic.

In just a few days, large lakes, some measuring several miles in area, disappeared. Hillsides have fallen. The landscape is left with a lot of large, sunken polygons.

It’s evidence that permafrost, the long-frozen soil below the surface, is thawing. That’s bad news for the communities built above it – and for the global climate.

As an EcologistI am interested in these dynamic landscape interactions. I have been documenting how permafrost-driven landscape shifts have increased over time. These hidden changes are a warning sign for the future.

Illustration of a thermokarst landscape showing permafrost, ice wedges, polygons, erosion, lake drainable and fires

An illustration of how permafrost can affect the Arctic landscape.
Victor O. Leshyk, from Schuur et al. 2022. Permafrost & Climate Change: Carbon Cycle Feedbacks From the Warming Arctic. Annual Review of Environment and Resources Volume 47 (in presse)

What is permafrost and how does it work?

Permafrost, a perennially frozen soil that covers, is About 25% of the land is covered by forestsIn the Northern Hemisphere, Alaska, Canada, Russia and Russia are all examples. It is rich in the organic matter of long-dead animals or plants, which has been frozen in time.

These frozen soils are able to preserve the structural integrity in many northern landscapes. They provide stability to vegetated and non-vegetated surfaces, much like load-bearing support bars in buildings.

Permafrost, ground ice and other forms of ground-ice are more vulnerable to melting and thawing as temperatures rise. These frozen soils become more unstable as they warm, causing the delicate interwoven fabric that has shaped these dynamic ecosystems for millennia to unravel. Wildfires are increasing in Arctic. Have been increasing the risk.

A man in Greenland stands above a large crack in the ground.
Thawing permafrost may cause it to sink and crack, causing roads and buildings to be unstable.
Orjan F. Ellingvag/Corbis via Getty Images

Under the surface, something else is active – and it is Global warming: Increasing the impact. Microbes begin to consume organic matter from soils that have been frozen for thousands of years when the ground freezes.

These MicrobesCarbon dioxide and methane are potent greenhouse gasses that are released. They further increase the temperature of the atmosphere by escaping into it. A feedback loop is createdWarmer temperatures cause more soil to thaw, which releases more organic material for microbes and produces more greenhouse gases.

The evidence: Lakes disappearing

Evidence of climate change caused by humans is increasing across the permafrost extent.

The Large lakes disappearingThe striking example of recent patterns in northern landscape transitions is a large area of multiple square miles.

As the drainage channels become wider and deeper, the lakes drain laterally. Vertically, the taliks allow water to drain away from the lakes.

There is overwhelming evidence to suggest that the surface water is receding in permafrost-rich regions. Satellite observations and analysis show that lake drainage could be possible Linked to permafrost degrading. I and my colleaguesIt increases with longer, warmer summers.

A landscape of lakes showing one losing its water.

Gullies that are created by thawing soil drain a Arctic Coastal Plain lake in northern Alaska.
Christian Andresen & Mark J. Lara, CC BY ND

This insight was a result of some of the Highest rates of catastrophic lake flooding – drainage that occurs over a few days due to permafrost degradation – on record were observed over the past five years in northwestern Alaska.

The livelihoods of Indigenous communities will be affected by the disappearance of lakes at the permafrost extent. Water quality and water availabilityImportant for waterfowl, fish, and other wildlife shift.

Slumping hills, polygon fields

Hillsides in the Russian and North American Arctic are also experiencing a thaw-and-collapse of buried ice glaciers, which causes soil, plants, and other debris to slide downslope.

A new study from northern Siberia revealed that disturbed land surfaces were the result of a recent study Increased over 300%Over the past 20 years. Similar studies were done in Northern Northwestern CanadaSlumping was also seen in these areas, which was also more common in warmer and wetter seasons.

Several slumps along a valley, with signs of more slumps about to form

Slumping hillsides show how easily thermokarst landscape erodes in Canada’s Aulavik National Park.
Sarah Beattie/Parks Canada
A person stands in front of an ice wedge showing in an eroded hillside. The wedge is more than twice the height of the person.
An ice wedge dating to the Pleistocene era in Noatak National Preserve Alaska.
David Swanson/National Park Service

Ice wedges can form in flat terrain, creating unusual patterns and changes across the landscape.

Over many decades or centuries, melting snow seeps into soil cracks. Ice blocks. These wedges cause troughs above the ground. Making the edges of polygons. Polygonal features Naturally formThis is due to the freezing and thawing process, which is similar to what happens at the bottom of dried mud flats. The ground below collapses as the ice wedges melt.

Even in the extreme cold high Arctic, the effects of a few unusually warm summers can have dramatic consequences. Change the landscape’s surfaceTransitioning from flat terrain to undulating occurs when the surface sinks and melts ice below. The rates of ice-wedge thawing have been overall at 8%. Increased in response to climate change.

Thawing pingo and polygons – a mound and depressions formed by ice wedges – in the Northwest Territories, Canada.
Emma Pike /Wikimedia
Tundra polygons are caused by permafrost-ice wedges

This thawing was also witnessed in many Arctic regions. Wildfire. Recent research shows that. I was accompanied by colleaguesWildfires in Arctic permafrost areas increased the rate and vertical collapse of frozen terrain for up eight decades after the fire. Because both Climate warming wildfire disturbanceProjected to increase in the future. They may also increase the rate of change for northern landscapes.

Lower latitudes in lowland forest have also felt the effects of recent climate and environment change. There, ice-rich permafrost plateaus – elevated permafrost islands heaved above adjacent wetlands – have rapidly degraded across Alaska, Canada Scandinavia. They can look like cargo vessels filled with sedges, trees, and shrubs that sink into the wetlands.

Why is it important?

The decomposition of organic matter and dead plants in northern ecosystems has been limited by cold temperatures and short growing seasons. Nearly all northern ecosystems are affected by this. 50% of the global soil organic carbonThese soils are frozen.

The abrupt transitions we’re seeing today – lakes becoming drained basins, shrub tundra turning into ponds, lowland boreal forests becoming wetlands – will not only hasten the decomposition of buried permafrost carbon, but also the decomposition of above-ground vegetation as it collapses into water-saturated environments.

Permafrost across the Northern Hemisphere.
Russia has a large part of the world’s permafrost. After years of international cooperation, some Western institutions stopped funding scientific research in Ukraine after Russia invaded it in 2022.
Joshua Stevens/NASA

Maps showing temperature differences with increasing red in 2050

Red areas refer to unfrozen ground that is above permafrost. They are expected to appear in the 2050s, in five northern Alaska parks. Permafrost thickness is affected by climate and landscape history. For example, in summer, the active layer may be less thick than a foot near Prudhoe Bay (Alaska) or a few feet near Fairbanks. The average permafrost thickness is between 2,100 and 300 feet below these sites (about 660-90 meters), but it can vary greatly.
National Park Service

Climate models predict the impact of such an event. Transitions can be very difficult. For example, a recent modeling research was published in Nature CommunicationsThe possibility of permafrost degrading and landscape collapse could lead to a 12-fold increase of carbon losses in a scenario where there is strong warming by the end century.

This is especially important since permafrost has been estimated to contain approximately 75% of the world’s energy. The atmosphere has twice the carbon content today. The depths of permafrost vary widely. They can reach 3,000 feet in Siberia, and 2,000 feet in northern Alaska. They also rapidly decrease as you move south. Fairbanks, Alaska, has an average height of 300 feet (90m). Studies have shown that much of the shallow, 10 foot (3 meter) deep permafrost could be used to make ice. If the world is not destroyed, it will likely thawBased on its current temperature trajectory.

To make matters worse, microbes can also produce methane in waterlogged environments that lack oxygen. This is a potent greenhouse gases. 30 times more effective than carbon dioxide in warming the planet, though it doesn’t stay in the atmosphere as long.

A person's legs in tall boots standing in a bog with bubbles coming up.

The Arctic bog in Sweden bubbles up with methane as a result of permafrost melting.
Jonathan Nackstrand/AFP via Getty Images

It is unknown how significant a problem melting permafrost will be for the climate. We know that it is emitting greenhouse gases. However, the causes and consequences for permafrost melting and landscape changes that accompany it are not yet known. Frontiers of active research.

One thing is certain: The thawing and re-fining of previously frozen landscapes will continue for many years to alter the landscapes of high-latitude ecosystems. Slumping land and destabilizing soil means that people who live in these areas will have the opportunity to experience the risks and costs of sinking buildings and buckled roads.

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