Thawing chunks of Arctic sea ice trapped and sunk boats in the Atlantic Ocean
In the spring of 2017, a thick-hulled icebreaking research vessel, the Amundsen, had left its Quebec port en route to a research cruise in Hudson Bay. But the scientists aboard never made it to their destination: The Amundsen was diverted to rescue unsuspecting ships that had become entrapped by Arctic ice floes that moved into North Atlantic Ocean shipping lanes.
In past years, these masses of Arctic ice had mostly stayed put in their proper ocean -- the Arctic -- but increasing temperatures caused ice to melt, unclogging the channels connecting the Arctic to the north Atlantic, thus allowing massive surges of ice to flow freely south.
Scientists aboard the vessel documented the event and published their research in the journal Geophysical Research Letters on March 15, warning that the threat of ice-trapping events could become more commonplace.
Icebergs from Greenland's glaciers have long been a hazard for ships in the North Atlantic, particularly during the months of April and May. An iceberg from Greenland's Jakobshavn Glacier is thought to have been responsible for sinking the Titanic in 1912, for example.
But now boats are running into trouble because of sea ice getting flushed out of the Arctic.
"The warming in the Arctic and decline in ice cover is increasing the ability of this ice to be transported out of the Arctic, to areas that typically don’t have these large pieces of ice," said David Babb, a research scientist at the University of Manitoba's Center for Earth Observation Science, in an interview. Babb is a scientist who was aboard the icebreaker, and is a coauthor of the study.
The rescue events for trapped, punctured, and sinking ships specifically occurred in an expanse of ocean north of the large Canadian Island of Newfoundland. Two fishing ships were sunk by the ice, and other ships -- including ferries and an oil tanker -- had to be escorted to ice-free waters by the formidable Amundsen.
One fishing vessel could only travel a few hundred meters before getting stuck in the ice, Babb said.
To determine where exactly the ice was coming from, scientists on the Amundsen found themselves jumping onto the thick masses of ice in the Atlantic and taking samples of the ice thickness, temperature, and salinity. From their analysis, they found this thicker ice had traveled from the Lincoln Sea in the high Arctic, which is north of Greenland.
It's normal for thick masses of multiyear sea ice to travel down the west side of Greenland inside the frigid Nares Strait. Most winters, this ice gets blocked by natural ice dams that form in the narrow channel.
But these natural ice dams didn't form in the winter of 2016-2017, allowing the ice to move through. The sizable ice chunks then traveled unhindered through the mostly ice-less Baffin and Labrador seas, eventually collecting around Newfoundland.
The sea ice was further propelled by a third factor: Two early-spring storms whose onshore winds thrust the ice toward Newfoundland.
The Arctic sea ice extent in 2017-2018 has been some of the lowest since record-keeping began in 1979. January and February 2018 saw their lowest ice extents on record. And sometime later this century, scientists expect the Arctic to become completely ice-free during the summer months. But this doesn't mean vessels in the future will be safe from surges of ice, both from sea ice and land-based glaciers.
Young and relatively thin sea ice will still form in the Arctic during winter, said Babb. This ice, which can be up to two meters (six and a half feet) thick, can bunch together and grow into deformed masses. And it too, explained Babb, might travel swiftly down iceless straits and pose risks to ships in the Atlantic.
"It's the same hazard but it's coming from a different source," Babb said.
Scientists will once again board the Amundsen this spring, with plans to travel into Hudson Bay. This year, Babb said they've spoken with the Canadian Coast Guard who says there should be other icebreaking vessels in the area, should a surge of thick ice come down again from Arctic and entrap ships.
"We're leaving again to give it another shot," he said.
Mark was the science editor at Mashable. After working as a ranger with the National Park Service, he started a reporting career after seeing the extraordinary value in educating people about the happenings on Earth, and beyond.
He's descended 2,500 feet into the ocean depths in search of the sixgill shark, ventured into the halls of top R&D laboratories, and interviewed some of the most fascinating scientists in the world.
