A new study, led by the University of Alaska Fairbanks, reports that the methane that is being released by the thawing permafrost from some of the Arctic lakes could speed up climate change. The study, which was published recently in the journal Nature Communications, talks about the carbon that is released by the thawing permafrost which exists beneath thermokarst lakes.
These lakes are formed when the warm soils melt the ground ice, which leads to the permafrost’s collapsing and forming pools of water. These pools significantly speed up the thawing of the permafrost, which leads to food being available to microbes that consequently produce carbon dioxide and methane.
For the study, Katey Walter, lead author of the study, and her colleagues studied several thermokarst lakes in Alaska and Siberia over a 12-year long period. They measured the growth of these lakes and also recorded the amount of methane bubbling up top their surface. Combining the results of these two field works with the remote-sensing data of the changes that took place over the past two years in the lake, the research team determined that the “abrupt thaw” beneath these lakes could potentially release large amounts of permafrost carbon in the atmosphere this century- which might lead to the doubling of release from terrestrial landscapes by the 2050s.
The team found that the release of greenhouse gases beneath these thermokarst lakes is quite rapid than what scientists have observed in the past. “Thermokarst lakes provide a completely different scenario. When the lakes form, they flash-thaw these permafrost areas,” said Walter Anthony, who is an associate professor at the UAF’s Water and Environmental Research Center. “Instead of centimeters of thaw, which is common for terrestrial environments, we’ve seen 15 meters of thaw beneath newly formed lakes in Goldstream Valley within the past 60 years.”
The results of the study also suggest that now is the time that the emissions from thermokarst lakes are also included into global climate models, since they are now the hotspots of permafrost carbon release. It is extremely important that this happens as soon as possible, since methane is about 30 times more potent than carbon dioxide when it comes to trapping heat.
This abrupt thawing of the permafrost beneath the lakes is especially dangerous because unlike shallow and gradual thawing of terrestrial permafrost, it is impossible to reverse it this century. The research team suggests that even the climate models which estimate only moderate warming for this century should take these emissions into account. “You can’t stop the release of carbon from these lakes once they form,” Walter Anthony added. “We cannot get around this source of warming.”