For a long time, it was the shifts between ice ages and interglacial periods that determined how much carbon dioxide was in the atmosphere. During ice ages, CO2 levels fell, only to rise by around 100 ppm (parts per million) during interglacial periods. Previously, the main reason for this was thought to be that warmer and more mixed oceans cannot store as much carbon and therefore release it into the atmosphere between ice ages.
However, new research shows that thawing permafrost may have accounted for a significant proportion of carbon dioxide emissions.
"We have concluded that land north of the Tropic of Cancer, 23.5 degrees north, emitted a lot of carbon when the average temperature rose in the northern hemisphere after our last ice age. We estimate that this carbon exchange may have accounted for almost half of the rising carbon dioxide levels in the atmosphere," says Amelie Lindgren, researcher in ecosystem science at the University of Gothenburg and member of BECC.
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The article is published in full at University of Gothenburg's website: Thawing permafrost raised carbon dioxide in the atmosphere | University of Gothenburg
Scientific article in Science Advances: Massive losses and gains of northern land carbon stocks since the Last Glacial Maximum