[This 3-parter will look at the tundra-climate connection, modeling of tundra loss from future warming, and some new research.]
The tundra is probably the single most important amplifying carbon-cycle feedback. None of the IPCC’s climate models, however, include carbon emissions from a defrosting tundra as a feedback.
Yet, as NOAA reported last month (here), levels of methane (a far more potent greenhouse gas than CO2) rose last year for the first time since 1998, which may be an early indication of thawing permafrost. So it seems like a good a time for a review and update of what we know.
The tundra or permafrost is soil that stays below freezing (0°C or 32°F) for at least two years. Normally, plants capture carbon dioxide from the atmosphere during photosynthesis and slowly release that carbon back into the atmosphere after they die. But the Arctic acts like a freezer, and the decomposition rate is very low. The tundra is a carbon locker. We open it at our own risk.
We now know the Arctic contains far more carbon than previously thought (Science, subs. req’d) — nearly 1000 billion metric tons of carbon (some 3600 billion metric tons of carbon dioxide). That exceeds all the carbon dioxide currently in the atmosphere. The permafrost may contain more than a third of all carbon stored in soils globally, much of it in the form of methane. Problem: Global warming is melting the top layer of permafrost, creating the possibility of large releases of soil carbon, and that is a potentially devastating vicious cycle. We are defrosting the tundra freezer-and at an unprecedented rate.
We know methane is bubbling up out of the tundra far faster than previously thought (Nature, subs. req’d). In fact, a 2006 study by Alaska researchers (GRL, subs. req’d) finds rapid degradation to key elements of the permafrost “that previously had been stable for 1000s of years.” The study, titled “Abrupt increase in permafrost degradation in Arctic Alaska,” concludes that this recent degradation exceeds changes seen earlier in the 20th Century by a factor of ten to a hundred.
What’s happening in Siberia is even more alarming:

Earlier this month, at the United Methodist Church’s (UMC) Quadrennial General Conference, the UMC’s governing body, 

Newt Gingrich has recently been 

