Arctic permafrost has become a recent star in the climate change conversation, capturing the attention of scientists, activists and policymakers alike because of its ability to emit large quantities of carbon dioxide as well as methane — a particularly potent though relatively short-lived greenhouse gas — when it thaws. As temperatures rise in the Arctic, scientists are increasingly concerned that permafrost will become a major contributor to the greenhouse gas emissions driving global warming.

Studies of permafrost emissions are important in both estimating current levels of greenhouse gas emissions and making predictions for the future. So far, most studies have focused on the way permafrost behaves in the summer, when Arctic temperatures are at their highest. But a new paper in Proceedings of the National Academy of Sciences says we’ve been overlooking the importance of cold-season emissions of methane gas in particular — and possibly underestimating their impact in the future.

“The cold period in general is the time of the year that is warming the fastest in these Arctic ecosystems,” said the new study’s lead author Donatella Zona, an assistant professor at San Diego State University and research fellow at the University of Sheffield.

Until recently, scientists have known very little about how much methane is released by permafrost during the cold winter months, she said. But she noted, “Really, if we’re thinking about the future of climate change, we need to understand if this time of the year is important.”
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