A new study warns that shrinking summer sea ice in the Arctic could lead to the disappearance of bears and polar seals by 2100.
The shrinking of sea ice in the summer has been a long-standing concern because species depend on it for their survival. According to the new study published in Earth’s future magazine, if carbon emissions remain at current levels, summer ice will be completely gone by 2100.
ice and life
Most of the surface of the Arctic Ocean freezes in the winter and scientists believe this will continue for the foreseeable future, even if the climate is warm. When the ice melts in summer, currents and winds carry it great distances – even in the North Atlantic, but often to the far reaches of the Arctic, along the Canadian islands and Greenland.
This creates a marine ecosystem. Algae blooming on Arctic ice feeds on small animals. Fish, in turn, feed on these animals, and seals feed on fish, while polar bears, which are at the top of the food chain, feed on seals. The irregular terrain also helps seals create lairs, while polar bears live in ice caves during the winter.
However, as the climate warms, summer sea ice is shrinking rapidly and is now less than half the area it had in the early 1980s.
The study covered a huge area of one million square kilometers north of the coasts of the Canadian Archipelago and Greenland. Sea ice has traditionally been the thickest year-round in this region, and therefore the most resilient.
The researchers considered two scenarios – optimistic (if carbon emissions are checked) and pessimistic (if emissions persist). Summer ice in the region will decrease significantly by 2050. According to the optimistic scenario of the study, some summer ice may continue indefinitely. But under the pessimistic scenario, the summer ice will be completely gone by the end of the century.
Under the low-emissions or optimistic scenario, ice from the central Arctic will also disappear by mid-century. Locally formed summer ice will continue to remain in the last ice zone, but will only be one meter thick.
The study predicts that some polar bears, seals and other creatures could survive under the low emissions scenario. This species is found in similar summer conditions along parts of Hudson Bay and western Alaska.
However, under the high emissions scenario, even locally formed ice will be completely gone in summer by 2100. With no summer ice, ice-dependent ecosystems will perish.
Global lead researcher Robert Newton, who co-authored the study, told Columbia University’s School of Climate Change that if year-round ice went, ice-dependent ecosystems would collapse completely, and something new would start.
He added that new things will appear, but it may take some time for the new creatures to invade.
Newton said the fish and algae may swim from the North Atlantic, but it wasn’t clear if they could survive year-round.