Permafrost Possible Source of Abrupt Rise in Greenhouse Gases in Last Ice Age

Nov 22, 2014

Permafrost Regions — About one quarter of the earth’s surface in the northern hemisphere is frozen permanently. Scientists classify these permafrost regions into areas with (1) continuous permafrost, (2) discontinuous or unstable permafrost, or (3) occasional permafrost – depending on how much of the area is really frozen. © Hugues Lantuit / Alfred Wegener Institute

Background

The abrupt CO₂ rise about 14,600 years ago examined by the scientists was one of three rapid fluctuations in the carbon cycle during the transition from the last ice age to the present interglacial. This was shown by American colleagues (Marcott et al.; doi:10.1038/nature13799) by means of new CO₂ data from an ice core in West Antarctica that was published in the journal Nature at the end of October 2014.

Since CO₂ analyses on ice cores always contain only an averaged version of the atmospheric signal due to the inclusion process of the gases in the ice, the exact size of the CO₂ pulse is still uncertain. Nevertheless, scientists can clearly determine that the rates of change in atmospheric CO₂ during these abrupt CO₂ rises were significantly lower than the corresponding rates caused by fossil fuels of approximately 2-3 ppm per year, which are occurring today.

Details of the Study:

Peter Köhler, Gregor Knorr und Edouard Bard (2014): Permafrost Thawing as a Possible Source of Abrupt Carbon Release at the Onset of the Bølling/Allerød. Nature Communications 5:5520; DOI: 10.1038/ncomms6520

Source: AWI.