The result: the methane concentrations in the air after last year's heat wave indicate that increased gas emissions came from limestone formations beneath the thawing permafrost. The study is published in the journal Proceedings of the National Academy of Sciences (PNAS).
Permanently frozen permafrost soils cover large areas of the northern hemisphere, especially in northern Asia and North America. If they thaw in a warming world, this can pose dangers, because CO2 and methane are released during thawing - and amplify the anthropogenic greenhouse gas effect. "Methane is particularly dangerous here because its warming potential is many times higher than that of CO2," explains Prof. Dr. Nikolaus Froitzheim from the Institute of Geosciences at the University of Bonn. Pessimists therefore already spoke of an imminent "methane bomb." However, most previous projections showed that greenhouse gases from thawing permafrost will contribute "only" about 0.2 degrees Celsius to global warming by 2100. This assumption has now been challenged by a new study by Nikolaus Froitzheim and his colleagues Jaroslaw Majka (Krakow/Uppsala) and Dmitry Zastrozhnov (St. Petersburg).
Most previous studies only dealt with emissions from the decay of plant and animal remains in the permafrost soils themselves. In their current study, researchers led by Nikolaus Froitzheim made a comparison between methane concentrations in Siberian air, determined by satellite-based spectroscopy, and geological maps. They found significantly elevated concentrations in two areas of northern Siberia - the Taymyr Fold Belt and the rim of the Siberian Platform. What is striking about these two elongated areas is that the bedrock there is formed by limestone formations from the Paleozoic era (the period from about 541 million years ago to about 251.9 million years ago).
