Permafrost turns into a carbon time bomb

Permafrost is ground that is frozen all year round occuring in the Arctic and mountainous regions – the two regions most effected by the climate crisis. That creates a carbon timebomb. There are massive amounts of carbon stored in this everlasting ice and rising temperatures release more and more of this carbon.

For a long time the permafrost of the Arctic mostly produced headlines because it doesn´t only store massive amounts of carbon, but also intact carcasses and DNA of prehistoric wildlife. The continous frost preserves tissue better than in any other place around the world. This did not only spark wild dreams of reviving mammoths, but also allowed for an accurate reconstruction of the prehistoric landscape and wildlife in the tundra.

Climate change thaws the permafrost

However, throughout the last decades the permafrost has turned from a treasure chamber for palaeontologists into a time bomb. Climate change thaws the permafrost cm by cm. Normally, permafrost thaws up to a certain depth each summer and then completely freezes again during winter. This means layers below this depth of thawing during summer, normally around 20 cm, have been frozen for centuries or millenia. But climate change has already warmed the Arctic by 4°C.

This means a few cm more of permafrost thaw each summer. And not all freezes again during warmer winters. That creates a layer of water inbetween the ice. When the thawing process in summer reaches this layer, the layer of water, that does not freeze anymore, grows. This means more and more permafrost thaws permanently. This has two direct consequences.

Local and global consequences

  1. Decomposition, the breakdown of organic matter, kick starts.

All dead organic matter of millenia is locked in permafrost. When this organic matter thaws, bacteria start to metabolise it. This decomposition process releases the stored carbon into the atmosphere. And the scale is inimagineable. Permafrost stores more carbon than is currently in the world´s atmosphere. Rising temperatures could create a feedback cycle in which the speed of thawing increases more and more, producing ever more CO2 and warming the planet.

2. The ground becomes unstable.

As mentioned, permafrost is present in the Arctic and in mountainous areas. In both, it is essential for the stability of the ground. Melting permafrost in the Alps leads to mountains falling apart. And the ground in the Arctic turns into swamp without the stabilizing permafrost. That destroys infrastructure and creates large sinkholes.

Is rewilding a possible answer?

Now scientist discovered that nature once again might be able to help itself. Reintroducing large herds of herbivores like reindeers could help preserving the permafrost. High herbivore density means they trample the snow, so the snow layer is thinner, denser and hence less insulating. That means more ground freezes during winter, possibly stopping the continuous thawing process. In addition, they browse on bushes and trees that spread due to the thawing permafrost. These bushes and trees also accelerate the thawing.

It must however be noted that the necessary herbivore density has not existed since the Pleistocene, so ten thousands of years ago. Fossil density suggests that the wildlife density in the Arctic back then was similar to the current density in African savannah. But it is unknown why it decreased so massively. Hence, there are a lot of unknown factors involved in this idea.

The climate crisis affects the whole world

This shows again how the climate crisis affects every corner of the world. The Arctic and mountainous regions contain some of the largest Wilderness in the world and in Europe. Now, the very existence of this Wilderness is threatened. When people think about the impacts of the climate crisis, they often think about dry, hot areas, where it leads to water shortages. But rising temperatures lead to changes in all ecosystems – dry or wet, hot or cold.

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