Rapid and drastic melting last summer of the area predicted to be the Arctic’s final refuge of ice has been pinned to unusual meteorological conditions and climate change, with scientists suggesting the ‘Last Ice Area’ (LIA) is more vulnerable than previously thought.
The LIA is a region north of Greenland and Ellesmere Island in the Canadian territory of Nunavut that is predicted to harbour the last vestiges of Arctic summer ice once climate change claims the rest of the polar region’s permanent ice by around 2040. When that happens, it’s believed the area will become the final haven for wildlife that depends on sea ice for its survival.
The summer of 2020 saw unprecedented melt, and scientists looking to explain the phenomenon have used satellite imagery and a numerical model that accounts for environmental conditions in the Wandel Sea in 2020 to estimate the drivers of ice loss.
As detailed in a new paper in Communications Earth & Environment, the simulations undertaken by Axel Schweiger and colleagues from the University of Washington (UW), USA, suggested a multi-year ice-thinning trend driven by warming temperatures, leaving the LIA with a patchwork of areas of thin and thick ice, making it particularly vulnerable to melting. Extreme summer winds further drove ice breakaway and melt.
The record-low ice concentration in 2020 was surprising because the average ice thickness at the beginning of summer was close to normal.
“During the winter and spring of 2020 you had patches of older, thicker ice that had drifted into there, but there was enough thinner, newer ice that melted to expose open ocean,” Schweiger says. “That began a cycle of absorbing heat energy to melt more ice, in spite of the fact that there was some thick ice. So in years where you replenish the ice cover in this region with older and thicker ice, that doesn’t seem to help as much as you might expect.”
The researchers concluded that while extreme winds were the major driver of ice loss in 2020, climate change contributed to the thinness of the ice, and therefore its vulnerability to extreme events. With that in mind, they warned the LIA may not be as resilient as once thought, threatening the survival of Arctic species in this icy refuge as the planet warms.
“Current thinking is that this area may be the last refuge for ice-dependent species,” Schweiger says. “So if, as our study shows, it may be more vulnerable to climate change than people have been assuming, that’s important.”
Animals at risk include polar bears, which use the ice to hunt for seals, and walruses that forage from platforms of sea ice.
The researchers say there are further unknowns to be explored, including how more areas of open water will affect ice-dependent species over the long term.
“We know very little about marine mammals in the Last Ice Area,” says co-author Kristin Laidre, a principal scientist at the UW Applied Physics Laboratory. “We have almost no historical or present-day data, and the reality is that there are a lot more questions than answers about the future of these populations.”