The oldest, thickest, and toughest Arctic sea ice is weakening.

Arctic sea ice has starkly declined over the last 40 years, though polar scientists believed a region dubbed the “Last Ice Area” was largely resistant to melting as the planet warmed. Yet new research published in the scientific journal Geophysical Research Letters shows a hole nearly the size of Rhode Island opened up there in 2020, meaning even places with robust ice some 15-feet thick (or more) is increasingly susceptible in today’s warming climate.

“The scary thing is this area might not be as resilient as we think it is,” Arctic scientist Kent Moore told Mashable. Moore is a professor of physics at the University of Toronto Mississauga who led the research.

The Last Ice Area extends from northern Greenland westward through the Canadian Arctic Archipelago (the islands above Canada’s mainland). The ice crunches together between the islands, growing particularly thick and robust. Even when nearly all Arctic ice eventually melts each summer, perhaps sometime around mid-century as Earth continually warms, ice in the Last Ice Area (and the unique life it supports) may still remain. But how much ice might remain is now a prominent question.

“This area is transitioning to thinner ice,” said Moore.

The NASA satellite images below show the especially large 1,160-square mile hole, called a “polynya,” that opened up in the Arctic sea ice above Canada’s Ellesmere Island in May 2020. The thinning sea ice was no match for a powerful storm.

“The thinner ice can more easily be moved around or broken apart by strong storms, high winds, and large waves,” said Zachary Labe, an Arctic researcher at Colorado State University who had no role in the research. “Arctic sea ice is becoming thinner around the entire Arctic Ocean and during every month of the year.”

“This is just one indicator of how human-caused climate change is dramatically transforming the Arctic”

“This is just one indicator of how human-caused climate change is dramatically transforming the Arctic with a shift from older and thicker ice to younger and thinner ice,” Labe added.

In 2021, older, multiyear ice nearly dropped to a record low.

Scientists observed a large polynya (right) north of Ellesmere Island in May of 2020, along with smaller holes (left). Credit: NASA EOSDIS Worldview

The large May 2020 polynya was the first time polar researchers watched such a big hole opening up in the Last Ice Area. The study’s leader, Moore, looked back at older satellite footage and spotted only two other (previously unnoticed) instances of polynyas forming there, in 2004 and 1988. During the 2004 event, which scientists have more data about, the winds were even stronger than in 2020, but the hole was smaller.

“The difference now is that the ice is thinner overall,” said Walt Meier, a senior research scientist at the National Snow and Ice Data Center who had no role in the research.

The big Rhode Island-sized polynya suggests as Earth warms more big holes could open up in the Last Ice Area in the coming years, decades, and beyond, explained both Meier and the study’s author, Moore.

In the greater Arctic, diminished and thinning sea ice has major implications:

• Sea ice provides necessary habitat for unique Arctic life. “If we lose the ice, we lose all the ice-dependent ecosystems,” emphasized Moore. This includes many walruses, polar bears, bird species, fish species, and beyond. In the case of polar bears, the loss of ice extends the period of time these marine mammals must fast as they wait for their feeding grounds to freeze up each winter. As ice continues to dwindle, biologists expect many polar bear populations to die out this century.

• Less sea ice means an increasingly warmer Arctic, as open water soaks up more sunlight (sea ice reflects about 80 percent of sunlight back into space). In part due to diminished sea ice, the Arctic is warming about three times faster than the rest of the globe, and this warming makes wildfires more extreme during the summer, particularly in Siberia and the Arctic Circle. In 2019 and 2020, Arctic scientists observed unprecedented burning in the Arctic, as persistent, record-breaking heat settled over the region. This could be the start of a new Arctic fire regime.

• Permafrost, ground that typically stays frozen, is thawing. Arctic infrastructure like roads, buildings, and oil tanks, is beginning to fail.

• Although it’s still a hot area of atmospheric research with no clear consensus, there’s some evidence a heating Arctic affects global weather patterns, creating stagnant weather events like longer heat waves in the U.S., Europe, and elsewhere. 

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Both the Arctic, and the greater world, are changing in profound ways. Even the Last Ice Area isn’t immune.

“The planet is changing, and it’s changing more rapidly than we thought,” Moore said.

Mashable