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An unprecedented and extraordinary marine heatwave in West Antarctica has glaciologists spooked. [1]

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Date: 2023-02-13  

The ice shelves around Antarctica are an essential barrier, holding huge volumes of ice on the continent.

Research ships that arrived in West Antarctica during mid-December when conditions are most favorable have reported an unprecedented marine heatwave threatening the stability of the giant ice platforms.

Marine heatwaves worldwide have substantially increased over the past decades, but not so much in Antarctica. The deep ocean heat corrodes the ice shelf from underneath the ice creating tunnels and fissures that weaken the ability to provide resistance to land ice.

At the two most essential chunks of ice in the world, Pine Island and Thwaites, the pinning points that fasten the ice to the bedrock are disintegrating, sparking fears of runaway melt and rising sea levels.

Warm Circumpolar Deep Water (CDW) , which upwells poleward onto the continental shelf, is the primary mechanism that transports heat toward Antarctica’s marine-terminating glaciers. In recent years, warm CDW transport onto the continental shelf has been linked to accelerated basal melting of ice shelves

Bob Berwyn reports in Inside Climate News.

Despite “that extraordinary change, what we’ve seen this year is dramatic,” said University of Delaware oceanographer Carlos Moffat last week from Punta Arenas, Chile, after completing a research cruise aboard the RV Laurence M. Gould to collect data on penguin feeding, as well as on ice and oceans as chief scientist for the Palmer Long Term Ecological Research program. “Even as somebody who’s been looking at these changing systems for a few decades, I was taken aback by what I saw, by the degree of warming that I saw,” he said. “We don’t know how long this is going to last. We don’t fully understand the consequences of this kind of event, but this looks like an extraordinary marine heatwave.” If such conditions recur in the coming years, it could start a rapid destabilization of Antarctica’s critical underpinnings of the global climate system, including ice shelves, glaciers, coastal ecosystems and even ocean currents. Such radical changes have already been sweeping the Arctic, starting in the 1980s and accelerating in the 2000s. Data collected during Moffat’s most recent research voyage includes the first readings from temperature and salinity sensors that were deployed a few years ago, which will give the scientists a starting point for comparisons. Moffat said it’s “too early, and difficult” to attribute this year’s conditions to long-term climate change until some peer-reviewed results are published.

If the same marine conditions return again and again, it likely will lead to a collapse of the W Antarctic marine extensions within ten years. Check out the below video; the collapse includes areas I had not considered before.

Clouds cover the Amundsen Sea Embayment on NASA's worldview; satellite imagery is the only way to see the damage to the shelves at Thwaites and Pine Island.

And El Nino is coming. Good times.

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[1] Url: https://www.dailykos.com/stories/2023/2/13/2152663/-An-unprecedented-and-extraordinary-marine-heatwave-in-West-Antarctica-has-glaciologists-spooked

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