Glaciers Might Not Be Able To Recover From Climate Change

Crack Petermann Ice Shelf

A crack in Petermann Ice Shelf was observed by an international team of scientists during the Oden expedition in 2019. These cracks can eventually grow across the entire ice shelf, leading to the release of large icebergs into the ocean and potentially breakup of the ice shelf. Credit: Martin Jakobsson

Ice shelves are floating extensions of glaciers. A new study, published in Nature Communications, found that if Greenland’s second-largest ice shelf breaks up, it may not recover unless Earth’s future climate cools considerably. 

A group of researchers from Stockholm University and the University of California, Irvine investigated whether the Petermann Ice Shelf in northern Greenland might recover from a future breakup caused by climate change. They employed a complex computer model to predict the ice shelf’s potential recovery.

“Even if Earth’s climate stopped warming, it would be difficult to rebuild this ice shelf once it has fallen apart,” says Henning Åkesson, who led the study at Stockholm University.

“If Petermann’s ice shelf is lost, we would have to go ‘back in time’ towards a cooler climate reminiscent of the period before the industrial revolution to regrow Petermann,” Åkesson says.

Ice shelves reduce mass loss from our polar ice sheets. These gatekeepers thereby limit sea-level rise caused by climate warming. “The rationale to avoid breakup of ice shelves in the first place should be clearer than ever”, Åkesson says.

Glaciers are rapidly melting

Petermann is one of Greenland’s few surviving ice shelves, and it is being closely monitored by experts throughout the globe after Manhattan-sized icebergs broke off from the ice shelf in 2010 and 2012, leading Petermann to lose 40% of its floating ice shelf. Scientists are afraid that additional ice shelf breakdown, or even collapse, may hasten ice flow from the interior ice sheet. In 2018, a new crack in the center of the ice shelf was found, raising additional concerns for Petermann’s health.

Swedish Icebreaker Petermann Ice Shelf

Swedish icebreaker Oden at the front of Petermann Ice Shelf in 2019. The new study shows that if the ice shelf breaks up, it will be difficult to rebuild it. Credit: Martin Jakobsson

Ice-sheet experts are concerned

While this study focused on northwestern Greenland’s largest glacier, another grave concern is that the larger ice shelves found in Antarctica could be difficult to build back as well, should they break up too.

“This is just the first step, but chances are that our findings are not unique for Petermann Glacier and Greenland.” Åkesson says. “If they are not, near-future warming of the polar oceans may push the ice shelves protecting Earth’s ice sheets into a new retreated high-discharge state which may be exceedingly difficult to recover from.”

The ice-sheet experts stress that we need to pin down exactly how ice shelves break up, and how much more warming they now can withstand before they fall apart.

Reference: “Petermann ice shelf may not recover after a future breakup” by Henning Åkesson, Mathieu Morlighem, Johan Nilsson, Christian Stranne and Martin Jakobsson, 9 May 2022, Nature Communications
DOI: 10.1038/s41467-022-29529-5

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