One among the vast array of concerns that have arisen among scientists in terms of climate change, was a fear that thawing permafrost in the arctic would release large amounts of methane into the atmosphere. Methane itself is a strong greenhouse gas, and this scenario could have further accelerated global warming, in a vicious cycle.
Using decades worth of data from a site in northern Alaska, researchers have determined that methane emissions have not significant from the permafrost in the area. The findings were reported at the American Geophysical Union meeting on December 15th.
One co-author of the study, Colm Sweeney, said that “The ticking time bomb of methane has clearly not manifested itself yet.”
Emissions of carbon dioxide did rise in the period of the study, which Franz Meyer, remote sensing scientist from the University of Alaska Fairbanks, says “is still bad, it’s just not as bad” as increased methane emissions. Meyer also stressed that this research used data from only one site, and that “This location might not be representative” of emissions in the rest of the arctic. Just the top 3 meters of permafrost in the arctic contain 2.5 times as much carbon as the amount released into the atmosphere by human activity since the industrial revolution. Studies have suggested that as this permafrost thaws in response to global warming, microbes could convert this carbon into methane and CO2.
The prospect of methane emissions has been most concerning to scientists, since one ton of methane leads to about 25 times as much warming as one ton of CO2.
Data collected in Barrow, Alaska’s northernmost city, has shown that the area is warming twice as fast as the rest of the arctic in the past 3 decades. According to Sweeney, this “makes this region of the Arctic a great little incubation test to see what happens when we have everything heating up much faster.”
The data showed that despite some variation with temperature, levels of methane in the winds blowing off of the tundra in Barrow remained fairly stable since 1986. CO2 concentrations, on the other hand, have increased by roughly 0.02 parts per million since 1973, according to the researchers.
According to Sweeney, the thawing permafrost may be allowing water to escape, drying the soil in the area. Drier soil could lead these microbes to produce less methane, potentially counteracting the effects of warming.