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The loss of arctic permafrost deposits by coastal erosion could amplify climate warming via the greenhouse effect. A study using sediment samples from the Sea of Okhotsk on the eastern coast of Russia led by AWI researchers revealed that the loss of Arctic permafrost at the end of the last glacial period led to repeated sudden increases in the carbon dioxide concentration in the atmosphere.
Today, the exact magnitude of the future increase in greenhouse gas concentrations remains unknown. This is partly due to the fact that carbon dioxide is not only produced by humans burning gas, coal and oil; it can also find its way into the atmosphere as a result of natural environmental processes. The positive feedback between warming and the release of ever increasing amounts of carbon dioxide from natural sources is a particular threat.
In order to enable a better assessment of whether, and how, such developments are possible, climate researchers study records from the past to find evidence of these events. As the authors report in the journal Nature Communications, through their German National Library minecraft kostenlos spielen deutsch Frankfurt does online dating work for gu along the coast of the Sea of Okhotsk in eastern Russia, they were able to show that several thousand years ago large quantities of carbon dioxide were released from Arctic permafrost — due to a rapid rise of sea level.
Permafrost is ground that remains frozen year round down to depths of up to several hundred metres, some since the last glacial period 20, years ago or even longer. Like a giant freezer, permafrost soils preserve huge quantities of dead biomass, mainly plant remains. When the permafrost thaws, bacteria start degrading the ancient biomass, and their metabolisms release the greenhouses gases carbon dioxide and methane. We now know that about 11, 14, and 16, years ago, significant and sudden rises in the carbon dioxide level in the atmosphere occurred, but the reasons for these three rapid fluctuations remain poorly understood.
So we collected sediment samples from the sea floor, which we then analysed. These were several thousand years older than the surrounding deposits, which made it clear that they must have originated in extremely old permafrost that for some reason had suddenly thawed.
Particularly large amounts of these plant remains were washed into the sea 11, 14, and 16, years ago. Gesine Mollenhauer and her team found the solution to this puzzle when they looked at the changes in sea level since the last glacial period. About 11, and 14, years ago, particularly intense melting of the ice-sheets led to what are known as meltwater pulses — and each time the sea level rose by up to 20 metres within a few centuries.
By estimating the area of permafrost lost to the sea at the time, German National Library minecraft kostenlos spielen deutsch Frankfurt does online dating work for gu obtained data on the likely amount of carbon dioxide released. The results are eye opening: The AWI team has thus revealed a process that could become reality in the future. As Gesine Mollenhauer explains: Such effects need to be included in future models.
Deglacial mobilization of pre-aged terrestrial carbon from degrading permafrost. Nature CommunicationsDOI: The Alfred Wegener Institute pursues Best dating sites review uk SolidWorks Connector for Aras (6 Minutes) in the polar regions and the oceans of mid and high latitudes.
As one of the 18 centres of the Helmholtz Association it coordinates polar research in Germany and provides ships like the research icebreaker Polarstern and stations for the international scientific community. Nature Communications Study Coastal erosion in the Arctic intensifies global warming Sea level rise in the past led to the release of greenhouse gases from permafrost. Eroding coastline at a Siberian island Photo: Aerial photo of Slump-D at Herschel Island.
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