Satellite images revealing an Arctic ice cap destabilizing at “unexpected and unprecedented” speed have scientists questioning the long-term stability of some of the Earth’s polar ice caps.
A time lapse video using the images shows a portion of the Vavilov Ice Cap in northern Russia thinning and slowly spreading into the Kara Sea from 1985 until 2010, when the process began to accelerate. Between 2015 and 2016, deterioration had dramatically surged and the ice front had spilled more than 5 kilometers into the sea.
The images and data appear in the multi-institutional and multinational study “Massive Destabilization of an Arctic Ice Cap,” published in the journal Earth and Planetary Science Letters.
“The glacier increased its speed by 300 times to more than 80 feet per day in 2016. While we sometimes see certain glaciers around the world periodically surge with similar increases, there is no record of such surges at Vavilov,” said Matthew Pritchard, professor of earth and atmospheric sciences, who co-authored the study with his doctoral students Whyjay Zheng and William Durkin.
The study was led by Michael Willis, assistant professor of geological sciences at the University of Colorado, a former research associate at Cornell.
Unlike fast-moving glaciers, ice caps that are mostly frozen to bedrock are thought to be stable and respond slowly to climate change. The Vavilov Ice Cap’s rapid deterioration has scientists questioning whether it’s simply an anomaly, or if other polar ice caps might also be susceptible to accelerated change.
“In all of the glaciers that we’ve looked at in Russia, Vavilov really stands out as anomalous. Given the Vavilov Ice Cap’s geometry, small annual mass losses and no previous record of surging, this is a glacier that we had expected to be stable,” said Durkin.
The research team pieced together the ice cap’s deterioration using remote sensing technology from a constellation of satellites and high-resolution topographic maps of the Arctic region.
The study’s authors believe the accelerated change observed in the ice cap in 2010 started as a slow process as the glacier advanced for decades from the land into the ocean. The bed beneath the offshore portion of the glacier is likely low-friction, saturated marine sediments, according to the research team, which accelerated the movement and led to the glacier rapidly spilling into the sea starting in April 2015.
“Since 2016, the glacier has slowed down, but is still moving faster than its long-term average. We are continuing to monitor the glacier and are developing models of what happened and what the future of the ice cap could be,” said Pritchard, who added that the Vavilov may not recover to its previous state given the warming climate of the Earth.
High-latitude glaciers and ice caps cover about 450,000 square kilometers of the planet and hold back a potential 30 centimeters of additional sea-level rise, according to the study. The Vavilov Ice Cap has lost about 4.5 cubic kilometers of equivalent water between 2015 and 2016. That’s about half the volume of Cayuga Lake, or enough water to provide about 370 years of domestic water use for the Ithaca metropolitan area, according to the research team.
Source: Cornell University