Methane is 25 time more powerful than CO2 in trapping heat in the atmosphere. The “corks” holding back methane release from Arctic frozen grounds may now have started to pop.
Research published in Nature Geoscience last week describes 150,000+ sites in the Arctic that have been observed where methane is increasingly seeping out. The seeps are occurring in areas that are thawing as the polar climate warms and the ice melts. The methane had been trapped in the ground for millennia by glacial ice or permafrost, now receding. The article’s lead author, Katey Walter Anthony of the University of Alaska said: "As permafrost thaws and glaciers retreat, it is going to let something out that has had a lid on it.”
A short video from earlier field research illustrates her point:
Alaska Methane Bubbles (credit: Katey Anthony)
The researchers used aerial surveys to fly over Alaska and hiked across Greenland to gather day on where methane was bubbling up from the earth. By mapping the lakes and receding ice covered ground, it was possible to calculate the number of seeps. They determined that methane is now being released at ~250,000 metric tons per year representing 50 to 70 percent more gas than in the previous estimates.
Frozen Methane Bubbles Methane Increases 1978-2010
(credit: Nature Geoscience) (credit: NOAA)
One serious concern is the potential for a feedback loop to occur where increasing air temperatures melt even more frozen ground, which releases additional locked-up methane into the atmosphere, which further increases Arctic temperatures. If a feedback loop begins, it will require a very long time---centuries---to return to an equilibrium.
More field research will be required to determine the full extent of methane releases across the entire Arctic. However, it is often difficult to put the genie back in the bottle once the cork has been removed.