What is permafrost?
It’s a never-ending frozen layer which exists under the seasonally thawed surface layer of the ground, and over 18 million square kilometers at high latitudes or one-quarter of all the exposed land in the northern hemisphere consists of permafrost. Recent estimates are predicting that permafrost contains an estimate of 1500 petagrams of carbon, which is the same as 1.5 trillion metric tons of carbon.
A CU Boulder-led study has found out that the landscape and ecology of the circumpolar north are changing at a drastic rate because of the abrupt thawing of permafrost. This is because when it’s being thawed abruptly, it doubles the possibility of carbon emissions from the permafrost.
The study has highlighted the difference between gradual permafrost thaw, which affects permafrost and it’s carbon stores slowly, against comparatively abrupt types of permafrost thaw. About 20% of the Arctic region has conditions that are prone to abrupt thaw because of their ice-rich permafrost layer.
Such permafrost emits carbon in large amounts, which also includes releasing carbon dioxide and methane, which is more of a greenhouse gas than carbon dioxide. This means that if even 5% of the Arctic region is experiencing abrupt thaw, their emissions will be just the same as the rest of the areas that are experiencing gradual thaw.
Why is it important to thaw permafrost?
Permafrost is made up of rocks, soil, sand, and in special cases, cavities of pure ground ice. On average, it stores about twice as much as carbon as present in the atmosphere because it stores the remains of the living organisms, which flourished the Arctic once upon a time, such as dead plants and animals. It has been trapped in this without decomposing.
As the climate warms, it triggers gradual permafrost thaw that takes place over decades to centuries. But in the rest of the Arctic, where the ground ice content is high, abrupt thaw can take place in a few months, which causes extreme consequences to the landscape like erosion and sinkholes. This rapid process is called “thermokarst.”
Scientists state that new urgency should be brought to include permafrost in all types of climate models, besides implementing strong climate change policy and mitigation.