From Tallbloke’s Talkshop

March 22, 2023 by oldbrew 

They studied molecules from certain algae that are only produced when there is sea ice. Natural climate variation alone was all it took to reach the required temperature level.
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The „Last Ice Area“ north of Greenland and Canada is the last sanctuary of all-year sea ice in this time of rising temperatures caused by climate change.

A new study now suggests that this may soon be over, says Phys.org.

Icebreaker Oden in the sea ice north of Greenland. Credit: Martin Jakobsson, Stockholm University

Researchers from Aarhus University, in collaboration with Stockholm University and the United States Geological Survey, analyzed samples from the previously inaccessible region north of Greenland.

The sediment samples were collected from the seabed in the Lincoln Sea, part of the „Last Ice Area“. They showed that the sea ice in this region melted away during summer months around 10,000 years ago.

The research team concluded that summer sea ice melted at a time when temperatures were at a level that we are rapidly approaching again today.

„Climate models have suggested that summer sea ice in this region will melt in the coming decades, but it’s uncertain if it will happen in 20, 30, 40 years, or more. This project has demonstrated that we’re very close to this scenario, and that temperatures only have to increase a little before the ice will melt,“ says Christof Pearce, Assistant Professor at the Department of Geoscience, Aarhus University.

The researchers have used data from the Early Holocene period to predict when the sea ice will melt today. During this time period, summer temperatures in the Arctic were higher than today. Although this was caused by natural climate variability opposed to the human-induced warming, it still is a natural laboratory for studying the fate of this region in the immediate future.

In Aarhus the marine samples have been analyzed in collaboration with Associate Professor Marianne Glasius and academic technical staff Mads Mørk Jensen from the Department of Chemistry.

Among other things, they studied molecules from certain algae that are only produced when there is sea ice. The researchers can thereby determine when summer sea ice was present in the area.

Full article here.