The “last ice zone” north of Greenland and Canada is the last resort of sea ice all year long at this time of warming temperatures due to climate change. A new study now suggests that this may end soon.
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.
Sediment samples were collected from the seafloor of the Lincoln Sea, part of the “last ice zone”. They show that sea ice in this area melted during the summer months about 10,000 years ago. The research team concluded that summer sea ice melted at a time when temperatures were rapidly approaching again today.
“Climate models have suggested that summer sea ice in this region will melt in the coming decades, but it is uncertain whether it will happen in 20, 30, 40 years or more. This project has shown that we are very close to that scenario,” says Christophe Pearce, Assistant professor at the Department of Geosciences at Aarhus University said that temperatures would only have to rise slightly before the ice melted.
The researchers used data from the early Holocene to predict when sea ice will melt today. During this time period, summer temperatures in the Arctic were higher than they are today. Although this was the result of natural climate variability versus human-caused warming, it remains a natural laboratory for studying the fate of this region in the near future.
In Aarhus, the marine samples were analyzed in collaboration with Associate Professor Marianne Glacius and academic technical staff Mads Mörk Jensen from the Department of Chemistry. Among other things, they studied particles from certain algae that are only produced when there is sea ice. The researchers can thus determine when summer sea ice is present in the area.
wake up call
When the sea ice in the Lincoln Sea begins to melt during the summer months, it can have devastating consequences for the climate. When the white ice reflects the sun’s rays, the dark sea absorbs ten times more solar energy and thus increases global warming. Furthermore, it can affect ecosystems:
“Sea ice is the basis of many ecosystems. The algae we examined are food for fish, fish are food for birds, etc. How will marine ecosystems globally be affected if sea ice disappears? We don’t know the answer yet?” says Henrieka Detlef, associate professor at Department of Earth Sciences.
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 could 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 if we reduce greenhouse gas emissions and set ambitious policy targets. If we can keep temperatures stable,” says Henrieka Detlef. Or maybe you make it snow, and sea ice will come back to the area.”
This is what Christophe Pearce echoed:
“The study is a wake-up call, because we know it’s going to happen. This news doesn’t make the situation any more bleak, just more urgent. We need to act now so we can turn it around.”