There’s a lot of carbon stored in the Arctic’s thawing permafrost. According to our best estimates, it’s in the range of 1,300 billion tons (see Climate Change and the Permafrost Feedback). That’s more than twice the amount of carbon already emitted by fossil fuels globally since the 1880s. And the sad irony is that continuing to burn fossil fuels risks passing a tipping point beyond which rapid destabilization and release of those carbon stores becomes locked in.
(Global permafrost coverage as recorded by the World Meteorological Organization. A 2 C global warming threshold is generally thought to be the point at which enough of the Arctic permafrost will go into catastrophic destabilization, to result in a global warming amplifying feedback that then thaws all or most of the rest. The 2 C threshold was chosen because it is the bottom boundary of the Pliocene — a time when this permafrost store formation began. However, there may be some risk that enough of the store could become unstable at lesser levels of warming — crossing the tipping point sooner than expected. Image source: WMO.)
At issue is the fact that most of this carbon has been stored during the past 2 million year period of ice ages and interglacials. Due to human fossil fuel burning, we are now entering a period in which the Arctic is becoming warmer than at any time in at least the past 110,000 years. And with atmospheric CO2 levels now hitting and exceeding concentrations last seen during the Pliocene of 2-3 million years ago, large swaths of that carbon store may be in jeopardy of rapidly thawing. Such a thaw would release yet more CO2 and heat trapping methane into the atmosphere.
It’s something to worry over even if you’re not one of those, like Sam Carana, who’s concerned about a potential catastrophic methane release. And it doesn’t take a climate scientist to tell you that we’ve already seen some disturbing increases in methane emissions from thermokarst lakes, from permafrost regions themselves, through the permafrost and duff-destroying mechanisms of Arctic wildfires, from submerged seabed tundra in the ESS, and from the odd new features we’re now calling methane blowholes.
(Are large Siberian fires like this outbreak on August 1 of 2014 indicative that the Arctic permafrost carbon stores are nearing a critical tipping point? Top scientists think we should find out as quickly as possible. Image source: LANCE-MODIS.)
Top Woods Hole Scientist Calls for Tipping Points Investigation
With so much carbon stored in the permafrost, any level of warming that begins to unlock significant volumes of its massive store can result in passing a climate change point of no return. Setting off amplifying feedbacks that do not stop until much or all of that carbon is released and we’ve been propelled into new, much hotter, climate states. Given the fact that we are already starting to enter the range of Eemian temperatures — a period in which the world was as warm or warmer than now, but the Arctic stayed reasonably cooler — it’s more than reasonable to assume that such a danger is already upon us.
Today, a noted Woods Hole Scientist by the name of Dr. Max Holmes called such a threat “real and imminent” stating:
“The release of greenhouse gasses resulting from thawing Arctic permafrost could have catastrophic global consequences. The United States must lead a large-scale effort to find the tipping point – at what level of warming will the cycle of warming and permafrost thawing become impossible to stop. The real and imminent threat posed by permafrost thawing must be communicated clearly and broadly to the general public and the policy community.”
Dr. Holmes was joined by other Woods Hole scientists in issuing this call for more research into what they now consider a growing and immediate threat (see full press release here).
The generally accepted ‘tipping point’ for large permafrost store release tends to be in the range of 2 degrees Celsius. The problem is we’ve already emitted enough CO2, methane and other greenhouse gasses to warm the Earth by 2-4 degrees Celsius long term and by around 1.4 to 1.9 degrees Celsius this Century. So it appears we already have a good deal of momentum toward the accepted permafrost thaw and related carbon release tipping point. Dr. Holmes’ and his Woods Hole colleagues are calling for a focused effort to more accurately nail down that tipping point. To give us a better idea how close we really are and to provide a sense of urgency for avoiding what could best be described as a terrible brand of trouble.
Hat tip to Redskylite