The Arctic's 'Last Ice Area', which is the last sanctuary of all-year sea ice in the time of global warming, may soon be over, a new study suggests. The Last Ice Area is located north of Greenland and Canada. Climate change may cause the sea ice to disappear soon.
The study, led by researchers from Aarhus University, was recently published in the journal Communications Earth & Environment.
Around 10,000 years ago, sea ice in the Last Ice Area melted away during summer
The researchers collected sediment samples from the seabed in the Lincoln Sea, part of the 'Last Ice Area', and analysed them. The Lincoln Sea borders northern Greenland and Canada. The authors demonstrated that the sea ice in the Last Ice Area melted away during summer months around 10,000 years ago. There was a transition from perennial to seasonal sea-ice during the Early Holocene, modelling studies have suggested.
Climate models suggest that the Lincoln Sea will be the final stronghold of perennial Arctic sea-ice in a warming climate. However, recently, scientists observed prolonged periods of open water. These observations have raised concerns regarding the long-term stability of the Last Ice Area.
What happened to Lincoln Sea ice during the Early Holocene period?
During that Early Holocene period, the temperatures were at a level that Earth is rapidly approaching again today, as a result of which the summer ice melted.
Using data from the Early Holocene period, scientists have tried to predict when the sea ice will melt today. At that time, summer temperatures in the Arctic were higher than today.
The difference is that at that time the rising temperatures were a result of natural climate variability, but in the present day, the warming is induced by human activities. Despite the difference, the Last Ice Area is still a natural laboratory for studying the fate of the region in the immediate future.
There is a strong link between seasonal sea-ice conditions and regional atmospheric temperatures, according to the study.
The researchers studied molecules from certain algae that are only produced when there is sea ice, in order to determine when summer ice was present in the area.
How will melting of Lincoln Sea ice affect the climate?
Melting of the sea ice in the Lincoln Sea during the summer months can have major consequences for the climate. This is because in the absence of white ice, the dark sea will not reflect the rays of the Sun, and will instead absorb more than ten times as much solar energy. This, in turn, will increase global warming, and affect ecosystems.
Significance of the study
In recent decades, the warming in the Arctic has been much faster than in the rest of the world, with numerous studies reporting that the Arctic is warming either twice, more than twice, or even three times as fast as the globe on average. This phenomenon is known as Arctic amplification.
The authors concluded that in light of the anthropogenic warming and Arctic amplification, the study findings suggest an imminent transition to seasonal sea-ice in the southern Lincoln Sea, even if the global temperature rise is kept below a threshold of two degrees Celsius compared to the pre-industrial era, from 1850 to 1900. This means that even if the global temperature rise is below two degrees Celsius, the Lincoln Sea ice will not remain a year-round sanctuary of sea ice.