Sinkholes dot the landscape from Anchorage to Murmansk as surface soil layers thaw. Average Arctic temperatures have risen by 2 degrees Celsius in recent years, melting soil that had been frozen for millennia. And that means both mealtime for microbes—and bad news for climate change.
A new study from researchers at the U.S.'s National Snow and Ice Data Center suggests a permafrost thaw and subsequent microbial chowdown could add at least 126 gigatons of carbon to the atmosphere over the next 200 years. That's about half as much as humans have already added through burning fossil fuels over the last 200 years.
The frozen soils of the far north are already changing—from a tremendous storehouse of greenhouse gases to a tremendous source. That means any efforts aimed at limiting greenhouse gas concentrations will have to be even more stringent in reducing the burning of fossil fuels, clearing of forests and the like.
On the upside, thawed soils will allow shrubs and other plants to begin to march north, a process that is already happening, as well as the creation of new peatlands, which can store a lot of carbon. Their growth will likely counterbalance some of the increased emissions from melting permafrost.
But that balance will only last for a few decades, at best. And that makes cutting back on greenhouse gas emissions an even more pressing priority.