Potential future methane emission hot spots in Greenland

• Published in: Environmental Research Letters
• Main Authors: Marilena Sophie Geng, Jens Hesselbjerg Christensen, Torben Røjle Christensen
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2019
• Subjects: Greenland climate; climate change; permafrost; permafrost thaw; methane emissions; future emission hot spots; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Arctic; Greenland; Kangerlussuaq; Nuuk; Nuussuaq; Scoresby; Scoresby Land; Climate change; North Greenland; Scoresby land; Zackenberg
• Online Access: https://doi.org/10.1088/1748-9326/aaf34b; https://doaj.org/article/4af0454fcbea4eebaa662f3c7b4453aa

Climate models have been making significant progress encompassing an increasing number of complex feedback mechanisms from natural ecosystems. Permafrost thaw and subsequent induced greenhouse gas emissions, however, remain a challenge for climate models at large. Deducing permafrost conditions and associated greenhouse gas emissions from parameters that are simulated in climate models would be a helpful step towards estimating emission budgets from permafrost regions. Here we use a regional climate model with a 5 km horizontal resolution to assess future potential methane (CH _4 ) emissions over presently unglaciated areas in Greenland under an RCP8.5 scenario. A simple frost index is applied to estimate permafrost conditions from the model output. CH _4 flux measurements from two stations in Greenland; Nuuk representing sub-Arctic and Zackenberg high-Arctic climate, are used to establish a relationship between emissions and near surface air temperature. Permafrost conditions in Greenland change drastically by the end of the 21st century in an RCP8.5 climate. Continuous permafrost remains stable only in North Greenland, the north-west coast, the northern tip of Disko Island, and Nuussuaq. Southern Greenland conditions only sustain sporadic permafrost conditions and largely at high elevations, whereas former permafrost in other regions thaws. The increasing thawed soil leads to increasing CH _4 emissions. Especially the area surrounding Kangerlussuaq, Scoresby Land, and the southern coast of Greenland exhibit potentially high emissions during the longer growing season. The constructed maps and budgets combining modelled permafrost conditions with observed CH _4 fluxes from CH _4 promoting sites represent a useful tool to identify areas in need of additional monitoring as they highlight potential CH _4 hot spots.