Three things you should know about permafrost

How much do you know about permafrost? Maybe, like me, you’ve been aware that this layer of frozen soil is thawing, that it’s important in the global puzzle of climate change … and that’s about the extent of it. The great news for both of us is that my colleague James Temple just published two…

Résumé

Permafrost basics

Permafrost is a layer of soil that remains frozen for at least two consecutive years and covers about 15% of land in the Northern Hemisphere.

Most of today’s permafrost formed during the last ice age, meaning some of it has been frozen for thousands of years.

This frozen layer traps organic material like dead plants and animals, effectively locking away carbon that has been stored for centuries.

However, as global temperatures rise, permafrost thaws, allowing microbes to break down this organic matter.

This process releases greenhouse gases such as carbon dioxide and methane, which in turn accelerate climate change.

Since 1850, the Arctic permafrost has shrunk by about 12%, with the rate of loss increasing over the last 50 years.

Despite its significance, only a minority of climate models used in UN reports account for permafrost loss, and none include the rapid thawing triggered by events like heat waves or fires.

This oversight suggests that current climate projections may underestimate the speed and scale of future warming.