As Earth continues to warm, icy areas will continue to become less icy. That includes Arctic permafrost, or soil that traditionally never thaws, even in summer. Scientists are concerned that as the permafrost thaws, it will release tons of greenhouse gasses into the atmosphere, accelerating climate change. That will happen, say researchers from Northern Arizona University, but over a period of decades rather than years, as previously thought.
The research shows how human-induced climate change can be enhanced and multiplied by resulting natural factors.
“Human activities might start something in motion by releasing carbon gases but natural systems, even in remote places like the Arctic, may add to this problem of climate change,” said Ted Schuur, Northern Arizona University biology professor and lead author of the study.
Because soil is made up of so many decaying organic compounds, the Arctic and subarctic permafrost is believed to contain as much as 1,580 billion tons of carbon. As these compounds thaw, they’re gobbled up and digested by microbes, resulting in the release of carbon dioxide and methane, two of the greenhouse gasses responsible for global warming.
Some studies have posited that the Arctic permafrost may be something of a “ticking time bomb,” set to thaw rapidly and reduce massive amounts of greenhouse gasses over a period of just a few years. That’s unlikely, Schuur says, but the rate at which it thaws certainly matters. Schuur and his colleagues found that at the current rate of global warming, the permafrost thaw is more likely to release its huge stores of greenhouse gasses over a several decades instead.
Schuur says his findings will help change the way scientists predict climate change, adding that new computer models should take into account previously ignored factors like permafrost thaw. Models could also be improved to differentiate between methane and carbon emissions, helping scientists better identify sources of greenhouse gasses. In the end, though, it’s hard to know for sure what will happen.
“Our big question is how much, how fast and in what form will this carbon come out,” Schuur said. What scientists do know is that over the 30 years, the Arctic has warmed at twice the average rate for the planet.