Melting Ice Sheets Major Source of Methane

Melting Ice Sheets Major Source of Methane

Researchers from University of Bristol found that melting of Greenland Ice Sheet releases huge volumes of methane into the atmosphere

A team of researchers from University of Bristol studied samples of the meltwater that runs off a large catchment of the Greenland Ice Sheet during the summer months. The research relied on novel sensors to measure methane in meltwater runoff in real time. The team found that methane was continuously exported from beneath the ice. According to the team, around six tons of methane was transported to their measuring site from studied portion of the Ice Sheet alone. The investigation was led by Professor Jemma Wadham, Director of Bristol’s Cabot Institute for the Environment. The research was published in the journal Nature on January 2, 2019.

The team found that majority of the methane produced beneath the ice probably leaves the Greenland Ice Sheet in large, fast flowing rivers before it can be oxidized to carbon dioxide (CO2). Methane gas (CH4) is one of the most important greenhouse gas in the atmosphere after water vapor and CO2. Although methane is present in lower concentrations as compared to CO2, it is around 20-28 times more potent, according to the researchers. Therefore, even smaller quantities of methane have the potential to cause inconsistent impacts on atmospheric temperatures. Microorganisms are a major source of methane. Microorganisms convert organic matter to CH4 in the absence of oxygen, mostly in wetlands and on agricultural land. Other sources of methane include fossil fuels such as natural gas.

Significant volume of methane was detected in previous research in Greenland ice cores and in an Antarctic Subglacial Lake. However, the current research is a leading example that reported continuously release of methane from the ice sheet bed to the atmosphere from meltwaters produced in spring and summer in large ice sheet catchments. Lead author, Guillaume Lamarche-Gagnon, from Bristol’s School of Geographical Sciences stated that the team found unequivocal evidence of a widespread subglacial microbial system. The team found active microorganisms that were residing several kilometers under the ice.

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