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Thawing permafrost is shaping the global climate

Thawing permafrost shapes the global climate

Ice wedges (Yedoma) on the Bol’shoy Lyakhovsky, the southernmost island of the New Siberian Archipelago. Credit: Alfred Wegener Institute / G. Schwamborn

A new publication and interactive map summarize the current state of knowledge about the risks posed by permafrost soils – and call for bold action

How will climate change affect the permanently frozen soils of the Arctic? What are the consequences for the global climate, humans and ecosystems? And what can be done to stop it? in the news Frontiers in Environmental Sciences, a team of experts led by Benjamin Abbott of Brigham Young University, USA and Jens Strauss of the Alfred Wegener Institute in Potsdam summarize the current state of knowledge on these questions. In addition, an AWI group led by Moritz Langer has now created an interactive map of the past and future of permafrost. Both publications come to the same conclusion: in order to halt the dangerous trends in these regions, greenhouse gas emissions will have to be drastically reduced in the coming years.

Permafrost underlies as much as ten percent of the Earth’s surface. Especially in the Northern Hemisphere there are huge expanses in which only the top centimeters of the ground thaw in summer; the rest remains frozen all year round, to a depth of several hundred meters. At least, that’s the case so far. “Climate change poses a serious threat to these permafrost regions,” said Jens Strauss of the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI). There, land temperatures have risen two to four times faster than the global average. As a result, conditions on land and in the sea are changing much faster than expected. And this can have a range of dangerous consequences – for the climate, for biodiversity and for humans.

For example, these natural freezers contain the remains of countless plants and animals that are long dead. When the material thaws, microorganisms begin to break it down. In doing so, they convert the carbon compounds contained in them into greenhouse gases such as carbon dioxide (CO .).2) and methane (CH4), which could further exacerbate global warming.

However, it is no easy task to predict when and on what scale this will happen. “There are very different views among the public,” Strauss says. For some people, the permafrost areas are a ticking climate time bomb that will soon explode in the face of humanity. But others assume that only negligible amounts of greenhouse gases will be released in the Far North in the near future.

“They’re both wrong,” emphasizes the Potsdam-based researcher. “Admittedly, there’s no reason to believe that in a few years permafrost will suddenly release massive amounts of greenhouse gases into the atmosphere, pushing the climate past the tipping point.” However, the situation should not be trivialized either. “After all, the permafrost regions already emit almost the same amount of greenhouse gases today as Germany’s annual emissions.” And according to scientific estimates, these soils could release amounts of gas into the atmosphere over the next two centuries that would have the same effect as several hundred billion tons of CO.2

In addition, as the ice and snow cover shrinks, the surface of the permafrost areas gets darker and darker – and is therefore warmed more by the sun than in the past, when the landscape was still pure white. According to the current state of research, these two factors together are among the most important influences that could change the Earth’s climate.

Loss of permafrost soils threatens habitats – now is the time to act

The permafrost regions are also home to more than half of the Earth’s remaining wilderness. There live specially adapted flora and fauna species that depend on the survival of these ecosystems. In addition, the thawing permafrost will pose serious problems for the millions of people living in the Arctic. The ground often becomes unstable as the ice holding it together melts. Then it suddenly collapses or is eroded by the ocean, causing costly damage to buildings, streets, or other types of infrastructure. It also releases toxins such as mercury, which are found in high concentrations in animals and humans living in the Arctic.

For some communities in the Far North, their entire culture and way of life depends on the frozen ecosystems. “These people have done very little to cause climate change, but they are being hit particularly hard by it,” Strauss said. The authors of the study therefore consider taking measures to protect the permafrost as a matter of justice.

In reality, however, the fate of the permafrost will depend on the course political decision-makers take for greenhouse gas emissions over the next decade. In light of the rapid progress in renewable energy, the experts believe there are realistic possibilities to halve greenhouse gas emissions by 2030 and eliminate them completely by 2050. In addition, the local population should be supported in protecting intact ecosystems in the permafrost areas. “There’s certainly more we can do,” Strauss emphasizes. “We don’t have time for layoffs.”

Interactive map shows past and future changes in the permafrost soils

The urgency of the situation is apparent from an interactive map developed by his colleague Moritz Langer and his team. At the AWI, Langer leads the federal Department of Education and Research-funded young research group PermaRisk, which uses computer modeling to simulate changes in permafrost and associated risks. In this way, the group, in collaboration with experts from the University of Oslo, can now provide a virtual glimpse into the past and future of permafrost soils.

“Looking at the map, you can see how certain features of the climate and permafrost have changed since the year 1800,” explains Langer. How hot was it on the Earth’s surface? To what depth has the ground thawed? And how much carbon was there in this active layer? Not only can these aspects be established to date; forecasts are also possible. Using three different scenarios, the fate of the permafrost can be simulated for low, medium and high greenhouse gas emissions. They show that if we manage to keep global warming below two degrees Celsius, a large percentage of the permafrost soil will remain stable. “Unfortunately, we are currently moving towards a significantly higher warming,” Langer warns. And the accompanying simulation, based on warming between 4 and 6 degrees, depending on the region, paints a bleak picture: In this scenario, the great thaw will have spread across virtually every permafrost area by 2100.

Permafrost thaws faster than expected due to extreme summer rainfall

More information:
We must stop fossil fuel emissions to protect permafrost ecosystems, Frontiers in Environmental Sciences (2022). DOI: 10.3389/fenvs.2022.889428

Interactive map: permafrost.awi.eventfive.de/

Provided by Alfred Wegener Institute

Quote: Thawing permafrost shapes global climate (2022, June 29) retrieved June 29, 2022 from https://phys.org/news/2022-06-permafrost-global-climate.html

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