Sediments indicate a total melt "very closely" arctic in summer

March 22 () –

Sediment collected in the last permanent sea ice sanctuary in the Arcticnorth of Greenland and Canada, indicate that the total summer melt in this area is “very close”.

Researchers from Aarhus University, in collaboration with Stockholm University and the US Geological Survey, analyzed samples from the region, previously inaccessible.

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 during the summer months about 10,000 years ago.. The research team concluded that the summer sea ice melted at a time when temperatures were at a level we are rapidly approaching again today.

“Climate models have suggested that summer sea ice in this region will melt in the next few decades, but whether it will happen in 20, 30, 40 years or longer is unclear. This project has shown that we are very close to this scenario and that temperatures only need to rise a little before the ice melts,” says Christof Pearce, Adjunct Professor at Aarhus University’s Department of Geosciences.

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

In Aarhus, the marine samples were analyzed in collaboration with Associate Professor Marianne Glasius and Academic Technical Staff Mads Mork Jensen from the Department of Chemistry. Among other things, they studied molecules of certain algae that only occur when there is sea ice.. In this way, researchers can determine when summer sea ice was present in the area.

When sea ice in the Lincoln Sea begins to melt during the summer months, it can have major consequences for the climate. Where white ice reflects the sun’s rays, a dark sea will absorb more than ten times more solar energy and thus increase global warming.

In addition, it can affect ecosystems: “Sea ice is the foundation of many ecosystems. The algae we examine are fish food, fish are bird food, etc. How will marine ecosystems globally be affected if sea ice disappears? We still don’t know the answersays Henrieka Detlef, assistant professor in the Department of Geosciences.

According to the researchers from Aarhus University, the study can be interpreted as both good and bad news for the climate.

“The bad news is that we may see this happen very soon. The good news is that our data shows that the trend is reversible, and we can do something about it by reducing greenhouse gas emissions and setting ambitious policy targets. If we can keep the temperatures stable or maybe even make them drop, the sea ice would return to the area,” says Henrieka Detlef.

The research is published in the journal Communications Earth & Environment.