Over the weekend, the last intact ice shelf in the Canadian Arctic collapsed and turned into two ice islands. Scientists say warmer air temperatures and a lack of sea ice contributed to the breakup.
"These ice shelves can now break open due to the lack of pressure from sea ice against the sides of these ice shelves," said Dr. Adrienne White, ice analyst with the Canadian Ice Service for Environment and Climate Change in Canada, told Digital Trends. White was monitoring satellite imagery along the north coast of Ellesmere Island and the west coast of Greenland over the weekend when she noticed that the Milne Ice Shelf looked very different. it had a big break. In the next few days the shelf broke in two and now there are so-called ice islands. One is about 21 square miles; the other is about nine square miles.
"The winds are causing the ice pack to move away from the boundaries of the ice shelf so that it can actually erupt and the ice islands drift away from the front of the ice shelf," she said. NASA has a graph that shows how the amount of Arctic sea ice has decreased since 1979. In the long run, warming air temperatures and possibly warming sea temperatures can cause shelves to become thinner and more fragile.
"Ice racks are kind of a unique feature," said White. "You can really only find them along the north coast of Ellesmere Island, and there are some in parts of Russia" and Antarctica.
Ice shelves are thick ice sheets that are connected to a coast. They are often formed from glacial currents and melting sea ice that freezes on the shelf. It can take thousands of years, White said. "It's not something that builds up over a season." Over the millennia, they can accumulate thousands of feet in thickness.
In 2015, Carleton University's water and ice research laboratory sent a remote-controlled vehicle to an ice channel in the Milne Ice Shelf and discovered that the sediment contained many benthic (ground-dwelling) organisms living there. This ecosystem is likely to be hit by the collapse.
As the ice islands continue to disintegrate and move, White said the Canadian Ice Service will continue to monitor them. "We are very concerned about the safety of our ships and our coast guard," she said.