Scientists warn that the tundra near the Arctic circle contains a massive store of carbon, which is being released into the atmosphere at an alarming rate.
Permafrost, or soil that never quite thaws in the higher latitudes of the planet, is at serious risk from climate change. According to a press release from Northern Arizona University, a recent study warns that permafrost in the Arctic region contains about twice the amount of carbon that is already present in the atmosphere. And if it continues to speed up the thawing process, this carbon could be released quite quickly.
Billions of tons of organic carbon, stored underground from plants and animals that died millions of years ago, have remained frozen under the surface of the Arctic landscape. As temperatures in the Arctic continue to rise, however, the frozen structures in the permafrost begin to break down and this carbon is released, quickly turning into carbon dioxide once it is digested by an increasing number of microbes. In addition to carbon dioxide, these microbes release another harmful greenhouse gas: methane.
These gases pose a serious threat to our ability to control climate change. Under current estimates, scientists think we will need to significantly curb our carbon dioxide output from industrial and manmade sources like power plants and the transportation sector to have any hope at keeping the global temperature rise within a range of 2 degrees Celsius.
As permafrost thaws, however, the increased metabolism of ancient organic materials results in an even greater production of greenhouse gases. These, in turn, contribute to the rising temperatures in the Arctic by trapping in solar radiation and contributing to an even faster thaw rate. This is what scientists call a feedback loop, and it threatens to throw the global climate out of whack way more quickly than many models predict.
The study was published by NAU professor and Permafrost Action Team principal investigator, Ted Schurr in the journal Nature Climate Change this week.
Carbon cycles throughout the Earth’s systems at a relatively constant rate, and researchers can determine the age of carbon by measuring the level of radiocarbon inside of CO2 samples. Radiocarbon is also known as carbon-14, and carries two extra neutrons. Through radioactive decay, this molecule will eventually turn back into nitrogen. By measuring the relative amounts of carbon-14 and nitrogen in a given sample, scientists can determine the exact moment when it began to decay.
“As we warm up tundra experimentally, we can measure this increase of old carbon released in carbon dioxide that is emitted back into the atmosphere,” Schurr explained. “We’re using this experimental approach to show how warming conditions can shift these ecosystems out of their historic balance and mimic something we think will be happening to tundra everywhere as temperatures increase as the result of climate change.”