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.
The good news: The best NOAA analysis “suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.” Climate Progress first reported that finding 2 years ago. The lead author of that work confirms to CP it still remains true — despite the fact that methane levels have been rising for the past 5 years after a decade of little growth.
The bad news: Leading experts at NOAA, the National Snow and Ice Data Center and around the world now expect the permafrost to become a major source of atmospheric carbon in the next few decades (see “NSIDC/NOAA: Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100″ and “Nature: Climate Experts Warn Thawing Permafrost Could Cause 2.5 Times the Warming of Deforestation!“)
NY Times science reporter Justin Gillis has just published an excellent overview article, “As Permafrost Thaws, Scientists Study the Risks.” The piece makes clear we may be near a tipping point, citing University of Alaska scientist Vladimir Romanovsky:
In northern Alaska, Dr. Romanovsky said, permafrost is warming rapidly but is still quite cold. In the central part of the state, much of it is hovering just below the freezing point and may be no more than a decade or two from widespread thawing.
That thawing is of great concern because the permafrost contains a staggering amount of carbon, as Nature reported:
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.
The permafrost carbon thus represents a dangerous amplifying feedback or vicious cycle whereby warming leads to accelerated emissions, which leads to further warming. And that could lead to a point of no return, as Gillis reports:
In the minds of most experts, the chief worry is not that the carbon in the permafrost will break down quickly — typical estimates say that will take more than a century, perhaps several — but that once the decomposition starts, it will be impossible to stop….
That’s especially true since sea ice loss in the Arctic is happening faster than every major climate model projected — and accelerated Arctic warming and permafrost loss was linked to ice loss in a 2008 study by leading tundra experts, “Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss“:
We find that simulated western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate-change trends. The accelerated warming signal penetrates up to 1500 km inland and is apparent throughout most of the year, peaking in autumn. Idealized experiments using the Community Land Model, with improved permafrost dynamics, indicate that an accelerated warming period substantially increases ground heat accumulation. Enhanced heat accumulation leads to rapid degradation of warm permafrost and may increase the vulnerability of colder permafrost to degradation under continued warming. Taken together, these results imply a link between rapid sea ice loss and permafrost health.
And, of course, recent analysis suggests that our current “no policy” approach to climate will lead to staggering Arctic warming this century (see M.I.T. doubles its 2095 warming projection to 10°F — with 866 ppm and Arctic warming of 20°F).
So by any objective measure, the recent science and observations of the permafrost are increasingly worrisome.
While the NY Times‘ Gillis gets this right in the print edition, NYT blogger Andy Revkin asserts in a post published 3 days earlier focused on sea-based methane hydrates, “There’s an entirely different set of questions, also with relatively reassuring answers, about the vast amounts of methane locked in permafrost on land.” Not!
The NYT would seem to be schizophrenic on this crucial topic, but Gillis clearly has the story right and it isn’t reassuring at all.
Indeed, Gillis adds some new reporting that is very un-reassuring:
A troubling trend has emerged recently: Wildfires are increasing across much of the north, and early research suggests that extensive burning could lead to a more rapid thaw of permafrost.
Let’s look at the highlights of the important Gillis piece before returning to the sea-based issue: