Even in a world at 1 to 1.2 C warmer than 19th Century averages the permafrost is in trouble.
Already, vast thawed lands are starting to release carbon dioxide and methane. Thermokarst lakes bubble with the stuff. And pingos are now starting to erupt as the ice relinquishes the soils of Siberia. Russians, ironically concerned about the safety of an oil and gas infrastructure that helped to precipitate the warming in the first place, are starting to install seismographs to detect these new warming-induced eruptions from the thawed lands. Meanwhile, each new summer brings with it ridiculously warm temperatures, never before seen Arctic thunderstorms, and epic wildfires that rage over these growing piles of peat-like carbon laid down during the course of millions of years of glaciation — but now unlocked in just years and decades by an unnatural thaw.
Permafrost Thawing at 20 Percent Faster Rate Than We Previously Thought
Back in the late 1800s, permafrost covered about 17 million square kilometers of the Northern Hemisphere. In less than 150 years, that extent has been reduced by 2 million square kilometers due to the warming that has, to date, been produced by fossil fuel burning and related carbon emissions. Even worse, according to the new research, present temperatures alone are enough to, this Century, push permafrost coverage back to 12.5 million square kilometers.
That’s about 1/4 of the world’s permafrost gone due to just 1 to 1.2 degrees Celsius of global warming.
(A new study shows that 2 C worth of warming nearly cuts preindustrial permafrost extent in half to around 9 million square kilometers. Warming to 6 C above 1880s averages, which will occur so long as fossil fuel burning continues, will wipe out nearly all of the Northern Hemisphere’s permafrost. These thaw rates are about 20 percent more than previously estimated. Image source: An observation-based constraint on permafrost loss as a function of global warming.)
Warm the world by just another degree Celsius to 2 C above 1880s averages and, according to the new research, we’ll end up thawing another 3.5 million square kilometers of frozen ground to an ultimately reduced area of around 9 million square kilometers — cutting the Northern Hemisphere’s original permafrost coverage nearly in half.
Still More Urgency For Rapid Cuts to Fossil Fuel Burning
This newly identified permafrost thaw rate in response to human-forced warming is much faster than previously expected — representing a 20 percent acceleration compared to past permafrost thaw model estimates. And since the frozen ground of the world contains 1.2 to 1.4 trillion tons of carbon locked away over the course of millions of years, so rapid a thaw has big implications in a world warmed by fossil fuel burning.
(Wildfires burn through Siberia during August of 2014. Thawing permafrost lays bare billions of tons of carbon that can then be subject to release by microbes and the warming elements. Bacteria can break down the carbon — releasing methane and CO2. Thawed permafrost also forms a peat-like layer that can burn as more extensive fires rage across the heating Arctic. Image source: LANCE-MODIS.)
Back in 2015, scientists estimated that about 100 billion tons of permafrost carbon would hit the atmosphere over the course of the 21st Century due to human-forced warming. This warming feedback is equivalent to about 10 years of present fossil fuel emissions. Add an estimated 20 percent extrapolated from a faster than expected thaw to that rate and you end up with roughly 120 billion tons of carbon — or 12 years of present emissions bubbling and bursting up out of that previously frozen ground (approximately 40 ppm of CO2e heat forcing as feedback to the present warming).
It’s just another scientific finding of warming-related geophysical impacts occurring on timescales that were faster than previously expected. Still more added proof, as if we required any, that the need for cutting human fossil fuel emissions couldn’t be greater or more urgent. And when seismographs are now being constructed to detect permafrost methane bursts due to pingo detonations, it’s becoming more and more clear that we do not want to precipitate any more volatile Arctic thaw than we’ve already locked in.
Hat tip to Ryan in New England
Hat tip to Wili
Hat tip to Unnaturalfx