Levels of methane increasing rapidly in the Arctic
The levels of the greenhouse gas methane are increasing more than expected at measuring stations both on Svalbard and in Southern Norway.
“We see an alarming development,” senior researcher Cathrine Lund Myhre at the Norwegian Institute for Air Research (NILU) told the Norwegian News Agency NTB, via NRK.
The levels of methane increased sharply from 2013 to 2014, and preliminary results from measurements in 2015 indicate a continued strong increase. The results and measurements show that the concentration in the atmosphere of the main greenhouse gases with high anthropogenic emissions has been increasing over the period of investigation since 2001.
The levels of methane, which is the second most important greenhouse gas from human activities after CO₂, is the highest ever measured.
Compared with the average global increase, the levels of methane have gone far more up at the Norwegian weather stations, the new report “Monitoring of greenhouse gases and aerosols at the Zeppelin Observatory, Svalbard, and Birkenes Observatory, Aust-Agder, Norway” shows.
The measurements at Zeppelin Observatory characterise the development in the Arctic region, and Birkenes Observatory is located in an area in southern Norway most affected by long-range transport of pollutants.
In addition to the record high levels of methane, the Norwegian measurements also show record levels of CO₂, but this development was, unlike methane, expected.
Director of the Norwegian Environment Directorate, Ellen Hambro, said that the development gives reason for concern.
“It is very disturbing that the concentration of methane and CO₂ are increasing,” Hambro said. “It shows once again the urgency of implementing measures to reduce greenhouse gas emissions both in the short and long term.”
“If the reason is release of methane from thawing permafrost and from the Arctic Ocean, then it is alarming. It will give climate change a self-reinforcing effect,” Hambro said.
Many sources for more methane
It is unclear where the increased methane comes from.
“We do not know whether the increase is due to emissions from human activities, or whether climate change has initiated processes in nature that gives more methane into the atmosphere,” said Myhre, who heads the national monitoring program. “It is therefore very important that we can verify the changes to be able to detect them in time.”
The main sources of methane include boreal and tropical wetlands, rice paddies, emission from ruminant animals, biomass burning, and extraction and combustion of fossil fuels. Further, methane is the principal component of natural gas and e.g. leakage from pipelines; off-shore and on-shore installations are a known source of atmospheric methane.
The distribution between natural and anthropogenic sources is approximately 40% natural sources, and 60% of the sources are direct result of anthropogenic emissions.
Of natural sources there is a large unknown potential methane source under the ocean floor, so called methane hydrates and seeps. Further, a large unknown amount of carbon is bounded in the permafrost layer in Siberia and North America and this might be released as methane if the permafrost layer melts as a feedback to climate change.