maandag 13 februari 2023

Extraordinary Marine Heatwave That Could Threaten Antarctica’s Ice

Science

Antarctic Researchers Report an Extraordinary Marine Heatwave That Could Threaten Antarctica’s Ice Shelves

The inexorable rise of ocean heat is now evident off the coast of West Antarctica, potentially disrupting critical parts of the global climate system and accelerating sea level rise.

February 12, 2023

An iceberg calving from Antarctica's Brunt Ice Shelf in February 2021. Credit: Gallo Images/Orbital Horizon/Copernicus Sentinel Data 2021

Research scientists on ships along Antarctica’s west coast said their recent voyages have been marked by an eerily warm ocean and record-low sea ice coverage—extreme climate conditions, even compared to the big changes of recent decades, when the region warmed much faster than the global average.

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.

“But it seems to me that this might be a really unprecedented event,” he said. “These episodes of relatively rapid ocean warming that can persist for months have been occurring all over the place. They haven’t been common in this region.”

https://insideclimatenews.org/news/12022023/antarctic-ice-shelves-marine-heatwave/

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