Permafrost Thaw: A Tipping Point in the Climate Crisis

The world's permafrost regions are facing a major threat from heatwaves and wildfires, which are adding to the risks of reaching a tipping point. According to Gustaf Hugelius, a professor at the Bolin Centre of Climate Research at Stockholm University, the permafrost region is massive, covering 20m sq km, and stores 1,500 gigatons of carbon.

## What is Permafrost? Permafrost is ground that is frozen all year round, found mostly in Russian Siberia, Canada, Alaska, and parts of Europe. The permafrost region is a major concern because it stores a huge amount of carbon, which is three times more than all the living vegetation on Earth. Even small changes to this system can cause big changes in the atmosphere.

## The Tipping Point The thawing of permafrost can reach a tipping point when the frozen ground starts to melt, releasing carbon dioxide and methane into the atmosphere. This process can become self-reinforcing, leading to more warming and more thawing. The thawing of permafrost can create a fundamentally different landscape, with the formation of lakes, wetlands, and river gullies, which can change the hydrology and thermal conductivity of the soil.

## Consequences of Permafrost Thaw The consequences of permafrost thaw are severe, with the potential release of 200 to 300 gigatons of CO2 equivalents if the world warms by between 1.8C and 3.6C by the end of the century. This is many times more than the current emissions of the EU. The release of methane from permafrost thaw is also a major concern, as it is 30 times more potent as a greenhouse gas than carbon dioxide. The factors that determine whether permafrost releases methane or CO2 depend on whether the thaw leads to a dry or wet environment.

The amount of greenhouse gas that could be released from permafrost thaw is significant, with estimates ranging from 200 to 300 gigatons of CO2 equivalents. The following table compares the potential emissions from permafrost thaw with current emissions from major countries: | Emissions Source | Emissions Level | | --- | --- | | Permafrost Thaw (200-300 gigatons) | 200-300 gigatons CO2 equivalents | | EU Current Emissions | significantly less than 200 gigatons | | US Current Emissions | around 300 gigatons | | China Current Emissions | around 300 gigatons |

The only way to limit the thawing of permafrost is to reduce emissions rapidly. For every degree of global warming that is limited, 4m sq km of permafrost can be saved from thawing and releasing greenhouse gases. The greater the action to reduce emissions, the easier the challenge becomes. Unfortunately, there are no feasible geoengineering solutions on a broad scale, and the scientific uncertainty surrounding the precise rate of change and the pathways of permafrost thaw is high. However, it is virtually certain that a large magnitude of CO2 and/or methane will be released, and that global warming will accelerate in the Arctic.