New research indicates that summer Arctic Sea ice could soon become a relic of the past. Temperatures today mirror those of 10,000 years ago, when similar conditions led to the melting of this ice. The potential disappearance of this ice could have profound effects on both the climate and ecosystems.
In the face of escalating temperatures due to climate change, the “Last Ice Area” situated to the north of Greenland and Canada serves as the final refuge for perennial sea ice. However, recent research hints that this might not be the case for much longer.
A team of researchers from Aarhus University, working alongside Stockholm University and the United States Geological Survey, has managed to analyze samples from the previously unreachable region located north of Greenland.
“If we can keep temperatures stable or perhaps even make them fall, the sea ice would return to the area.” — Henrieka Detlef
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 as opposed to 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.
A wake-up call
When the 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 rays of the sun, a dark sea will absorb more than ten times as much solar energy and thereby increase global warming. Moreover, it can affect ecosystems:
“The sea ice is a base for many ecosystems. The algae we examined are food for fish, fish are food for birds, etc. How will the marine ecosystems be affected globally if the sea ice disappears? We don’t know the answer yet,” says Henrieka Detlef, an assistant professor at the Department of Geoscience.
According to the researchers from Aarhus University, the study can be interpreted as good and bad news for the climate.
“The bad news is that we can see this happening very soon. The good news is that our data shows the trend is reversible and we can do something about it if we reduce greenhouse gas emissions and set ambitious political goals. If we can keep temperatures stable or perhaps even make them fall, the sea ice would return to the area,” says Henrieka Detlef.
This is echoed by Christof Pearce: “The study is a wake-up call because we know that it will happen. This news is not making the situation more depressing, just more urgent. We have to act now so we can change it.”
Reference: “Seasonal sea-ice in the Arctic’s last ice area during the Early Holocene” by Henrieka Detlef, Matt O’Regan, Christian Stranne, Mads Mørk Jensen, Marianne Glasius, Thomas M. Cronin, Martin Jakobsson and Christof Pearce, 20 March 2023, Communications Earth & Environment.
Funding: Aarhus Universitets Forskningsfond, Vetenskapsrådet, Horizon 2020 Framework Programme.