What the 5th IPCC Assessment Doesn't Include
"Patterned ground" in Alaska’s Arctic National Wildlife Refuge. Frozen ground causes formations like these. Source: NSIDC
A heavyweight boxer in the climate change match is missing from the 5th climate assessment report released by the Intergovernmental Panel on Climate Change (IPCC) on Friday.
Permafrost, which is frozen ground that doesn't melt during the summer, covers 24% of the land in the northern hemisphere. Permafrost acts like a massive cryogenic chamber, stabilizing tens of thousands of years of organic matter, and stores approximately 1.5 trillion tons of carbon, which is twice the amount of carbon that's currently in our atmosphere. When the organic matter thaws, that carbon will be exposed to the elements, made available to escape into the air in the form of heat-trapping gases, with the potential to knock out our efforts to slow down global warming with a one-two punch.
This effect, called the permafrost carbon feedback, is not present in the global climate change models used to estimate how warm the earth could get over the next century. But research done in the past few years shows that leaving the permafrost effect out of the climate models results in a far more conservative estimate of how our climate will change. Scientists predict that greenhouse gas from permafrost alone could lead to an additional 1.5°F of warming by the end of this century, on top of our day-to-day human emissions.
To put that in perspective, the earth has already warmed around 1.5°F since 1901, and climate scientists suggest that we should keep global warming below 3.6°F in order to avoid a "dangerous" level of warming. The climate models used in Friday's report, without the permafrost effect, estimate that by the end of this century we will have warmed at least 7°F if we continue "business as usual" with no efforts to reduce our fossil fuel consumption.
Permafrost contains more than soil. It acts like a massive cryogenic chamber, stabilizing tens of thousands of years of organic matter like leaves and plant roots that would otherwise be broken down by bacteria and releasing greenhouse gases into the air.
In addition to carbon dioxide, an exceptionally potent greenhouse gas is released from organic matter. In moist areas, most of the emissions will be of methane, a gas that has 20 to 25 times the warming power of carbon dioxide over a 100-year period.
There is no doubt that permafrost is melting. Trees that have grown for years in permafrost are finding themselves on softer soil, which causes them to lean or tip over, creating "drunken forests." Roads are crumbling, buildings are melting into the earth, and along coastlines, the earth is melting into the sea. The big question is how much methane and carbon dioxide will be released, and how quickly, as the frozen tundra continues to thaw.
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