by Fikret Onal
Back in February, a major study found that thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s, releasing 100 billion tons of carbon by 2100. That study, by NOAA and the National Snow and Ice Data Center, conservatively assumed all of the carbon would be released as CO2 and none as the far more potent greenhouse gas, methane (CH4).
But that is unlikely, as this video of University of Alaska, Fairbanks, assistant professor Katey Walter Anthony, suggests:
A new article in Nature, “Climate change: High risk of permafrost thaw” (subs. req’d) concludes:
Arctic temperatures are rising fast, and permafrost is thawing…. Our collective estimate is that carbon will be released more quickly than models suggest, and at levels that are cause for serious concern.
We calculate that permafrost thaw will release the same order of magnitude of carbon as deforestation if current rates of deforestation continue. But because these emissions include significant quantities of methane, the overall effect on climate could be 2.5 times larger.
I’ve written about the introduction of methane from thawing Arctic regions. Now we are seeing more specific numbers. When these methane traps are released, there really is no way to put them back. The amount of GHG released increased spontaneously at much higher rates.
This is where anthropogenic causes of warming can become tremendously enhanced by the release of non-anthropogenic GHG. There could be 1,700 billion tons of carbon held in the soils of the North. This is larger than earlier projected because they found that the carbon extend much deeper in the permafrost than thought. This amount is twice as much as is present in the atmosphere right now.
Models estimate that perhaps 1/5 of this could be released over the next century.
Its release would rapidly increase global temperatures. And if much of it was in the form of methane the effects would be tremendous, as methane is 70 times better at holding in the heat from the greenhouse effect as carbon dioxide.
The largest extinction event in Earth’s history coincided with a huge release of methane, when global temperatures rose about 6 °C. The warmest recent period – the PETM – also saw a rise of 6 °C and a huge release of methane.
The large-scale release of methane from both polar waters and melting land could be the tipping point that substantially increases temperatures,. Once we hit that, even stopping our own use of fossil fuels will have little effect. The heat-trapping carbon is already there and beyond out ability to deal with.