Frozen tundra may be more sensitive to rising temperatures than previously thought, releasing methane and worsening global warming

Pools of melted permafrost from the air (Pic: Flickr/Steve Jurvetson)

Permafrost, the layer of permanently frozen ground that lies just beneath the Earth’s surface in the polar regions, has been found to be more sensitive to the effects of global warming than climatology had recognised.

In a study published in Nature Climate Change journal, scientists say they expect the warming to thaw about 20% more permafrost than previously thought, potentially releasing significant amounts of greenhouse gases into the Earth’s atmosphere.

The study, conducted by climate change experts from the universities of Leeds and Exeter and the Met Office, all in the UK, and the universities of Stockholm and Oslo, suggests that nearly four million square kilometres of frozen soil – an area larger than India – could be lost for every additional degree of global warming the planet experiences.

Permafrost is frozen soil that has been at a temperature of below 0C for at least two years, trapping large amounts of carbon that is stored in organic matter held in the soil.

When permafrost thaws, the organic matter starts to decompose, releasing greenhouse gases, including carbon dioxide and methane, and raising global temperatures.

The study says it is estimated that there is more carbon contained in the permafrost than is currently in the atmosphere.

Thawing permafrost has potentially damaging consequences not just for greenhouse gas emissions, but also for the stability of buildings and infrastructure in high-latitude cities.

Roughly 35 million people live in the permafrost zone, with three cities and many smaller communities built on continuous permafrost.

The study says a…