Projected carbon emission (in billions of tons of carbon a year) from thawing permafrost. From a 2011 NOAA/NSIDC study with moderate warming and other conservative assumptions.

A US article about a potential Carbon Time Bomb in the Arctic says that the good news is that the best National Oceanographic and Atmospheric Administration analysis “suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.” (CH4 is methane. And apparently methane hydrate is what you get when you mix water and methane -also known as swamp gas – in freezing conditions. I guess,  a kind of frozen watery gas.)

But the bad news is that NOAA, the National Snow and Ice Data Centre and other scientists expect that thawing permafrost will become a major source of carbon emissions over the next decades.

The article reports the journal Nature as saying:

The latest estimate is that some 18.8 million square kilometres of northern soils hold about 1,700 billion tonnes of organic carbon4 — the remains of plants and animals that have been accumulating in the soil over thousands of years. That is about four times more than all the carbon emitted by human activity in modern times and twice as much as is present in the atmosphere now.

Tundra graphic from New York Times - click to enlarge