Scientists have discovered large amounts of the potent greenhouse gas are being released from an Icelandic glacier. The study of Sólheimajökull glacier, shows that as much as 41 metric tons of methane are released every day during summer months. This is roughly equivalent to the methane produced by 136,000 cows.
The research is the first published field study to show methane release from glaciers on this scale. This is a huge amount of methane lost from glacial meltwater, rivaling the world’s most methane-producing wetlands. Researchers discovered that the methane is coming from microbiological activity at the bed of the glacier.
Methane has a global warming potential 28 times that of carbon dioxide (CO2).
Normally when methane comes into contact with oxygen it combines to form carbon dioxide and water, so the methane effectively disappears. Glacial meltwaters rich in dissolved oxygen reaching the bed of an ice mass convert any methane present into carbon dioxide.
But at Sólheimajökull, as meltwater reaches the glacier bed it comes into contact with gases produced by the Katla volcano. These gases lower the oxygen content of the water, resulting in some of the methane produced by the microbes dissolving into the water and being transported out of the glacier without being converted.
Iceland and Antarctica have many ice-covered active volcanoes. Researchers caution it is unclear how these effects will play out. There may be short-term spikes in methane while the glacier melts and thins, in the long-term the process could be self-limiting because without ice the conditions to produce methane are no longer there.