Arctic sea ice is like a living, breathing organism. Each winter, it inhales cold air and causes a freeze up, then in the summer, it exhales a breath of older sea ice from the high Arctic into the seas on its southern edge.
New research shows that the region is starting to hyperventilate, though. Warming oceans have caused more old sea ice to melt or sputter out into lower latitude. That’s made the remaining icepack more unstable, and could mean that even as more northerly shipping routes open up, other shipping lanes normally free of heavy ice could be clogged (at least until all the ice melts 🙃).
The findings were published this week in Geophysical Research Letters, and come courtesy of a team of Canadian researchers whose experiment in the Arctic didn’t quite go as planned. The CCSG Amundsen, the Canadian Coast Guard’s icebreaking research vessel, was conducting a study in Hudson Bay in late May
to study the impacts of climate change and stream flows on ice and the bay’s ecosystem. But the Arctic had other plans.
Prolific icepack piled up off Newfoundland at a time when the region was usually ice-free. Ice floes more than 26-feet thick and icebergs up to 50 feet in height crowded shipping lanes and made for dangerous travel. That caused the Coast Guard to divert the vessel to help with search and rescue and tracking the ice there. During the trip, two fishing vessels sunk and a ferry that provides supplies to remote communities had to rely on the Amundsen for safe passage.
“I’ve been to the Arctic 15 times and I’d say that this broken-up, but yet very thick, ice pack was unique and not like the ice that I’ve worked on in other places,” David Babb, one of the study’s authors who was on the diverted vessel, told Earther in an email.
When life gives you frozen lemons, you have to make frozen lemonade, which is exactly what Babb and other the scientists on board the ship did. They decided to figure out how all this old, thick ice had ended up off Newfoundland.
“This was a completely opportunistic study,” Babb said. “Considering the Amundsen was outfitted to study sea ice, albeit sea ice in Hudson Bay, we took advantage of the time between escorts and search and rescue duties and were able to sample the ice and figure out what the physical properties of this ice cover were and then how it came to be in area where thick multiyear ice is not typically present.”
Using samples and drone footage, they were able to determine that the ice had characteristics only found in the high Arctic. They then used satellite images to trace its journey, which began in October 2016 in the Lincoln Sea above Greenland and Ellesmere Island. From there, the ice pushed through the strait separating the two, and slowly wended its way through the Nares Strait and Baffin Bay before sliding down Canada’s northeast coast.
The reason why so much old thick ice was able to travel this circuitous route is somewhat counterintuitive. An arch of older ice usually blocks the Nares Strait, essentially allowing the Arctic to hold its breath a bit. But in May, that arch broke down and caused the Arctic to exhale a huge gasp of its old sea ice.
“This breakup is in no way catastrophic,” Nathan Kurtz, an ice scientist at NASA’s Goddard Space Flight Center, told NASA Earth Observatory at the time. “But it is worth noting that the early breakup of this arch puts some of the oldest and thickest Arctic sea ice in a more vulnerable state and will increase the flow of ice through the strait this year.”
This is bad news because old ice is essentially the glue that binds Arctic sea ice together. According to the most recent Arctic Report Card, the extent of ice older than four years declined from 981,000 square miles in March 1985 to just 50,000 square miles by March 2017.
Rising temperatures driven by climate change have caused this old ice to disappear, and a replacement of thinner, single-year icepack has left the Arctic more prone to widespread melting each summer. It’s a big reason why the summer sea ice minimum has declined by more than 13 percent per decade since satellite measurements began in the 1970s. The winter maximum is also decreasing, though at a slower rate. It has hit a record low for past three years in a row, and this winter might have just missed setting the record for a fourth straight year.
The disappearance of old, thick ice has opened up the Northwest Passage and other northern shipping routes. But in a weird twist, it also means that southern Arctic shipping routes normally free of ice in spring could have to contend with the increasingly shifty icepack of the Arctic.
“The relation between multiyear sea ice and shipping is interesting,” Babb said. “Yes, declining multiyear sea ice coverage should lead to longer open water seasons and reduce the risk posed by multiyear sea ice to shipping vessels. However, due to the transport of multiyear sea ice, it will continue to represent a hazard along Canada’s east coast and within the Canadian Arctic Archipelago along the Northwest Passage.”
Eventually old ice could completely disappear, further changing the ice regime. Researchers expect summers could be completely ice-free as early as the 2030s. All of this raises a host of commercial and national security concerns as the world races to cope with—and in some cases, take advantage of—the most rapidly changing region of the world.