Melting Permafrost Below Arctic Lakes Is Even More Dangerous to the Climate, NASA Warns
Scientists have worried for years that rising temperatures will free carbon trapped in frozen soil in the Arctic, accelerating the pace of climate change but now they believe abrupt thawing below lakes is even more dangerous.
A new study funded by the NASA, warned Arctic permafrost’s expected gradual thawing due to climate change and the associated influx of greenhouse gases to the atmosphere may actually happen within a few decades, much earlier than previously thought.
A massive store of carbon has been locked underground in the Arctic’s permanently frozen soil known as permafrost. As Earth’s climate continues to warm and permafrost thaws, soil microbes in the permafrost can turn that carbon into the greenhouse gases, which then enter into the atmosphere and contribute to climate warming. Abrupt thawing takes place under a certain type of Arctic lake, known as a thermokarst lake that forms as permafrost thaws.
The research team measured carbon release at 72 different locations on 11 thermokarst lakes across Siberia and Alaska, plus five locations without lakes, to calculate how much greenhouse gas was being produced and how old the carbon it contained was. Then, they used this data to make sure the models they were building were on the right track.
When permanently frozen dirt melts, the bacteria trapped inside it become active again, munch through whatever organic material is in reach, and produce carbon dioxide and methane, which are both powerful greenhouse gases. But when that happens below thermokarst lakes, the process is even grimmer because the water at the surface speeds up the melting below.
Using a combination of computer models and field measurements, the team found that abrupt thawing more than doubles previous estimates of permafrost-derived greenhouse warming. They found that the abrupt thaw process increases the release of ancient carbon stored in the soil 125 to 190% compared to gradual thawing alone.
The study was published in the journal Nature Communications. Lead study author Katey Walter Anthony, an ecologist at the University of Alaska, Fairbanks, said in a NASA statement about the research – “We don’t have to wait 200 or 300 years to get these large releases of permafrost carbon” and further added, “Within my lifetime, my children’s lifetime, it should be ramping up. It’s already happening but it’s not happening at a really fast rate right now, but within a few decades, it should peak.”
The research suggests that even in the scenario where humans reduced their global carbon emissions, large methane releases from abrupt thawing are still likely to occur.