Iceland’s glaciers and ice caps cover almost half of or located nearby to Iceland’s numerous volcanoes. The fourth largest ice cap, Mýrdalsjökull, sits directly on top of the Katla Volcano. That volcano erupts about twice every century and last erupted in 1918.
Newsweek has the story:
Researchers found that up to 41 tonnes of methane is released through meltwater from the Sólheimajökull glacier every day over the summer months. The study, published in Scientific Reports, is the first to show methane is released from glaciers on such a large scale.
Methane is a greenhouse gas far more potent than carbon dioxide. It is becoming an increasing concern because of its potential to contribute to climate change. In Arctic regions, methane is locked up in permafrost—ground that is permanently frozen. As global temperatures increase, the soil thaws and methane is released, contributing to further warming.
Identifying and understanding previously unrecognized sources of methane—like the latest study on glaciers—is hugely important to climate change models. If this volcano and glacier is representative of other similar systems, it could mean masses of previously unaccounted methane are being released into the atmosphere.
“At the moment, this large quantity of methane has only been observed to be released from Sólhiemajökull glacier in Iceland,” study author Peter Wynn, from the U.K.’s University of Lancaster, told Newsweek. “However, where glaciers and volcanoes interact together in similar fashion elsewhere in the world, there is every possibility methane could also be released there too. There is increasing evidence for large zones of geothermal activity beneath the world’s biggest ice sheets in Antarctica and Greenland, so there could be a large amount of methane being produced there.”
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Further analysis allowed them to find the exact sources of the methane—microbiological activity on the glacier bed. When methane comes into contact with oxygen it normally combines to form carbon dioxide. However, at Sólheimajökull when the meltwater reaches the bed of the glacier it comes into contact with gasses from the volcano. These gases lower the oxygen content in the water,
The volcano, the team believes, provides the conditions necessary for microbes to thrive and release methane into the meltwater—the geothermal heat makes the volcano into a giant incubator.
Unrelated to the methane story is this NASA Earth Observatory report about the icecap, Myrdalsjokull.
In 1890, Iceland's glacier coverage peaked for the first time since the end of the Ice Age. Since that peak, however, rising temperatures led many of the region's glaciers to begin retreating. A cooler climate in the 1940s allowed some glaciers to briefly advance, but since the 1990s, the pattern has been steady retreat.
“Sólheimajökull, the long outlet glacier on the southwest side of the ice cap, which has been retreating as much as 50 meters (164 feet) per year. This particular glacier is easily accessible to tourists, as the parking lot is moved almost annually.