Scientists have long feared that as the world gets warmer, thawing permafrost may lead to a significant effect on global warming. But now new research suggests that this same Arctic permafrost may actually help us adapt to climate change.
At least, that's according to new findings published in the journal Nature, which details how gradual, prolonged release of greenhouse gases from permafrost soils in Arctic and sub-Arctic regions may buy society some time to figure out how to deal with dramatic environmental changes occurring around the world.
"Twenty years ago there was very little research about the possible rate of permafrost carbon release," co-author A. David McGuire, US Geological Survey senior scientist and climate modeling expert with the Institute of Arctic Biology at the University of Alaska Fairbanks, said in a news release. "In 2011, we assembled an international team of scientists into the Permafrost Carbon Network to synthesize existing research and answer the questions of how much permafrost carbon is out there, how vulnerable to decomposition it is once it's thawed, and what are the forms in which it's released into the atmosphere."
Permafrost soils absorb so much carbon that the frozen North contains about twice as much as there is in the atmosphere today. And while that's good news, keeping the greenhouse gas from building up in the air, this system could one day be compromised - exploding in what scientists call a "carbon bomb."
As the world continues to warm and Arctic permafrost thaws, microbial breakdown of organic carbon increases and can accelerate the release of carbon dioxide (CO2) and methane into the atmosphere - creating even more warming and permafrost thaw. (Scroll to read on...)
Permafrost has warmed nearly 11 degrees Fahrenheit (-11 Celsius) in the past 30 years, according to researchers. In the 1980s, the temperature of permafrost in Alaska, Russia and other Arctic regions, for instance, averaged to be almost 18 F (-7 C). Now the average is just over 28 F (-2 C).
Within the next century, researchers expect permafrost to decline by as much as 70 percent, which may lead to a significant effect on global warming.
So with all of this melting permafrost, it would seem then that the popular big "bomb" theory is in our future, with a massive release of carbon one day threatening to accelerate climate warming. However, this study says that is not the case.
"The data from our team's syntheses don't support the permafrost carbon bomb view," McGuire explained. "What our syntheses do show is that permafrost carbon is likely to be released in a gradual and prolonged manner, and that the rate of release through 2100 is likely to be of the same order as the current rate of tropical deforestation in terms of its effects on the carbon cycle."
When it comes to climate models, most scientists want to incorporate the permafrost carbon feedback cycle, but whether they do or don't is a matter of their priorities given the multitude of issues that such models must consider, McGuire and his colleagues note.
"If society's goal is to try to keep the rise in global temperatures under two degrees C and we haven't taken permafrost carbon release into account in terms of mitigation efforts, then we might underestimate that amount of mitigation effort required to reach that goal," McGuire said.
In order to better understand our fate in this warming world and what we can expect, taking into account melting Arctic permafrost, the research team recommends improved observation networks, including remote sensing capabilities to quantify real-time CO2 and methane emissions from permafrost regions.
At least this study provides some hope yet that society can adapt to climate change as we try to avoid its irreversible impacts.
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