Methane release from retreating glaciers in the Arctic

On a trip to Norway to give a presentation on microbial production of methane (methanogenesis), Dr. Sasha Turchyn of the University of Cambridge was met with questions from local scientists about methane recently discovered in glacial fed groundwater springs. Curiosity surrounding this new methane source led to a coalition of scientists, including UBC Earth Oceans and Atmospheric Sciences Assistant professor Hal Bradbury, seeking to uncover the mechanism of this novel kind of methane release, the original methane source, and the scale of methane emissions from glacial groundwater springs. The group’s findings were published last week in Nature Geoscience in an article titled ‘Groundwater springs formed during glacial retreat are a large source of methane in the high Arctic’.

The fieldwork led by Gabrielle Kleber included groundwater sampling from 78 terrestrial glaciers on Svalbard over three years. The research revealed methane previously trapped under glaciers or permafrost is seeping out of the ground as glaciers retreat faster than permafrost can expand, leaving a gap in the ice cap through which methane can escape. The glacial meltwater forms the groundwater springs that carry methane out from under the glaciers. These methane emissions, equivalent to ~8% of Norway’s anthropogenic oil and gas emissions, primarily come from thermogenic reactions taking place over thousands of years in organic-carbon rich bedrock underlying the glaciers, rather than from a more recent biological source. These are the same kind of rock formations valued for their oil and gas reserves. 

Unfortunately, emissions of this kind are likely to increase as the process forms a positive feedback loop, prompting further glacial retreat. Glaciers that run into the ocean, known as marine-terminating glaciers, make up most of the glaciers in the high arctic and do not currently contribute to methane emissions from groundwater springs. However, in the coming years as these glaciers retreat inland, they may also become an important source of methane. The article concludes by urging climate experts to consider these kinds of feedback mechanisms, which are likely present in other parts of the Arctic besides Svalbard. Such unaccounted for feedback loops are likely to blame for the rapid rate of Arctic warming that is far exceeding model predictions. 

Due to the high impact nature of this research, it has already gathered much attention from the scientific community and beyond. Many news outlets including the Washington Post, Vancouver Sun, Insider, and even Men’s Journal have posted articles highlighting the recent publication.