Research details sea ice’s relationship to changing climate
New research is challenging conventional theories of the relationship between sea ice levels and global climate change.
The new study examined sediment core from the Southern Norwegian sea first formed between 32,000 and 40,000 years ago, finding that dramatic sea ice melt occurred before the abrupt period of warming over the period the ice was formed.
The data suggest that there were substantial changes in the sea ice cover in the southern Norwegian Sea between 32,000 and 40,000 years ago, according to Dr Henrik Sadatzki from the Department of Earth Science and Bjerknes Centre for Climate Research, University of Bergen.
“Most extensive sea ice conditions occurred at the onsets and early parts of cold periods over Greenland and the most pronounced open-ocean conditions occurred at the onsets of the abrupt changes to warm periods over Greenland,” Dr Sadatzki said.
UNSW Scientia Fellow Dr Laurie Menviel who works with the Climate Change Research Centre performed numerical model simulations of climate conditions that highlighted the tight coupling between the Atlantic Meridional Overturning Circulation and sea-ice cover in the Norwegian Sea.
The research suggests an enhanced sea ice cover contributed to insulation of the cold, high-latitude atmosphere from relatively warmer waters that were present in the Norwegian Sea beneath the sea ice lid. In turn, sea ice reduction allowed for heat release from the exposed Norwegian Sea waters to the atmosphere, which was a prime ingredient in shaping the abrupt warming of the Dansgaard-Oeschger climate events in Greenland.
The research paper, Sea ice variability in the southern Norwegian Sea during glacial Dansgaard-Oeschger climate cycles, is available here.