Permafrost: a ticking time bomb

From Reuters 

Just centimetres below the Earth’s surface is a ticking time bomb that could detonate as global temperatures rise. It's called permafrost.

Found at high altitudes[latitudes], Permafrost is a lot like concrete; ice binds together soil, rocks, sand and organic matter. Some of that organic matter includes the remains of plants and animals that have been frozen since the last Ice Age, more than 11,000 years ago

Now, human-induced climate change – caused by the buildup in the atmosphere of greenhouse gas emissions from industrial activity, mainly the burning of coal, oil and natural gas - is raising global temperatures and driving heat waves that can cause permafrost to thaw.

How bad will it get?

Permafrost covers almost 20 million square kilometres, or about five times the size of the European Union. With unfettered industrial emissions, nearly half of the world’s near-surface permafrost is expected to thaw within 20 to 40 years.  Scientists fear that permafrost emissions - whatever the mix of carbon dioxide and methane - will outpace trees' ability to absorb them. There is more than three times as much carbon frozen in permafrost as in all of the forests on the planet, scientists say.

Scientists have already found dramatic signs of permafrost thaw: in Siberia, giant craters are forming as gases from decomposing matter build up underground and then explode.