Existing estimates of how much methane is emitted from the Arctic need to be revised after a new international study investigated methane emissions from both wetlands and the upland in Greenland. The result shows that emissions may be far smaller than expected, although more methane is likely to be released into the atmosphere. Behind the study is an international research team, including post-doc Ludovica D’Imperio and head of center Bo Elberling from the DNRF’s Center for Permafrost (CENPERM) at the University of Copenhagen. The study was recently published in the scientific journal Nature Climate Change.
The rise in global temperatures in recent years may result in serious methane emissions as the methane-containing permafrost in the Arctic thaws. Researchers have tried to estimate the expected release of the gas species, which is both stored deep in the permafrost and produced near the surface. Now the estimates we have so far need to be revised following the publication of an international study involving researchers from the DNRF’s basic research center CENPERM at the University of Copenhagen. In the study, researchers constructed a model of methane emissions from both wetlands and the Greenland catchment.
The result shows that, although more methane is likely to be released into the atmosphere, emissions from Greenland can be far less than expected and that methane levels vary depending on whether they come from wetland or dry catchments. The study was conducted in collaboration with researchers from the US and China, among others, and was recently published in the scientific journal Nature Climate Change.
”The work is an example of the importance of a close collaboration between modelers and field scientists. The current model results are the first step in further downscaling with more high-resolution data, which is already ongoing for Greenland. Greenland is different from the average Arctic region due to the limited number of wetlands and the vast amount of dry upland soils,” said Professor Bo Elberling, head of center at CENPERM and senior author behind the study.
The study not only considered methane emitted in Greenland’s wetlands (methanogens) but also investigated and measured methane from the upland (methanotrophs) and its effects in a warmer climate. Soils from the wetlands emit methane to the atmosphere when the production of methanogens is greater than the methane consumption of methanotrophs. Methanotrophs in these soils require high-level methane concentrations to survive. In contrast, high-bonding methanotrophs in Arctic mineral lands require less than 1% of the methane concentration level that allows them to thrive in the wetlands. This means they can survive at low methane concentration levels in the atmosphere, thereby extracting methane from the atmosphere.
”In that sense, Greenland is already considered a net sink of methane, meaning that the amount of methane taken out of the atmosphere exceeds the amount being released from the wetlands,” said Elberling.
At CENPERM, post-doc Ludovica D’Imperio and center manager Bo Elberling have been responsible for data collection and the inclusion of field data in the current work. Together, the two researchers have made detailed measurements of the trends in methane emissions from different locations in Greenland.