Nitrous oxide, known to most as laughing gas, occurs naturally in peatland permafrost, a type of frozen ground that covers about a quarter of the Arctic. In addition to causing goofy non sequiturs to pour out of dental surgery patients, nitrous oxide is a greenhouse gas with 300 times the warming power of carbon dioxide. And as climate change continues to bake the Arctic at ever-higher temperatures, that nitrous oxide (N2O) may start seeping out of the peatland permafrost.
Right now, scientists don’t include nitrous oxide in climate change models, because very little has been detected leaking out of the upper layers of permafrost so far. But a study published Monday (May 29) in the journal Proceedings of the National Academy of Sciences suggests that as rising temperatures thaw deeper and deeper layers of permafrost, that may change.
The researchers took 16 core samples of peatland permafrost from Finnish Lapland and warmed them inside the lab. They found that in places where the permafrost is covered by plants, nitrous oxide emissions will remain low, because plants take up nitrogen from the soil and are “very effective at reducing N2O emissions,” Carolina Voigt, a researcher at the University of Eastern Finland and a lead author of the study told Australia’s ABC News.
But in places where the peatland permafrost is bare of vegetation, nitrous oxide emissions can increase as much as fivefold as the permafrost thaws. According to the researchers, their work suggests peatland permafrost could emit as much nitrous oxide as tropical forests—currently the largest natural source of the greenhouse gas—do now. Eventually, the peatland permafrost will release enough nitrous oxide into the atmosphere to meaningfully contribute to climate change.The gas will create a feedback loop of its own, the researchers say, much like carbon dioxide seeping from the thawing permafrost is beginning to do now.
The results of the lab-based study are still hypothetical, Jeremy Mathis, director of the Arctic Research Program at the National Oceanic and Atmospheric Administration and who was not involved in the study, told E&E News.
But, he said, the new research does add weight to the larger projection that greenhouse gases from permafrost will accelerate climate change on the whole, which will in turn thaw the permafrost further.
“It’s just this cycle that starts to feed back on itself that is much more pronounced in the Arctic than it is down in the lower latitudes, so that’s why we see the Arctic warming,” Mathis told E&E News. “Right now, it’s warming at least twice as fast as the rest of the planet, and the trend is continuing to look upward from that perspective, so this warming effect and this exacerbation of the warming effect in the Arctic I think is going to continue, given all the complexities of the system that’s in play.”