A widening of an eighty mile wide ice stream is the latest concern by glaciologists in West Antarctica to show signs of extreme stress. The river of ice is the Thwaites glacier which holds 2 feet of sea level rise. Thwaites, Pine Island and Crossen ice shelves all of which are weakening together in the Amundsen Sea Embayment would raise levels by four feet if they were to collapse together.
A recent Stanford University study published in the AGU has found the widening to be an accelerator of ice flow within the main trunk of the ice stream Thwaites is nicknamed the Doomsday Glacier for it’s potential to raise sea levels quickly as it is the cork which holds back a total of eleven feet of sea level rise in the entirety of West Antarctica.
The findings are yet another warning of the deglaciation of the planet's air conditioners. We are in unknown and dangerous waters.
The report occurred before the massive iceberg b22A broke away in December of 2022 from the undersea mountain where it had been lodged for twenty years. The loss of the iceberg exposed the tongue of the weakened glacier to the power of the Pine Island Gyre and the open ocean itself. Several pinning points failed, but the tongue survived. March and April are when ice shelves across the continent are at the most risk of shattering and collapse.
From Stanford University's presser:
In West Antarctica, the 80-mile-wide stream of sliding ice at the heart of Thwaites Glacier is likely to creep outward over the next 20 years, a change that could speed up ice loss, new research finds.
"It's like a torrential river eating away at the riverbanks and widening in the process," said senior study author Jenny Suckale, an assistant professor of geophysics at the Stanford Doerr School of Sustainability.
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Led by geophysics Ph.D. student Paul Summers, the researchers found that the observed thinning of Thwaites Glacier, together with changes in the slope of its surface and the conditions at its base, makes both sides prone to move a few miles outward over the next 20 years.
"We are considering relatively small changes in driving stress as would realistically occur in the coming two decades," Summers and colleagues write. Yet even this subtle widening—only about 2% of the glacier's overall width—could speed up ongoing ice loss.
"If the widening trend were to continue and were to accelerate, then we'd better know. It would mean that we would have to prepare for higher sea levels," said Suckale, who is one of dozens of scientists working to understand the glacier and its response to climate change as part of the International Thwaites Glacier Collaboration.
The abstract is in plain language. There is no paywall.
Thwaites Glacier, Antarctica, is losing ice rapidly, making it a major contributor to the uncertainty in current projections of global sea level rise. Many models have looked at how ice speed and thickness are likely to evolve over hundreds of years. Less scientific attention has been devoted to understanding the possibility that the main trunk of Thwaites Glacier might change in width. Here, we use a numerical model to show how ice thinning and could affect the width of the main trunk of Thwaites Glacier. We find that both lateral sides of Thwaites Glacier are prone to move, resulting in an overall widening of the main trunk when we apply thinning where it is currently observed. This widening of the glacier could speed up ongoing ice loss. To evaluate the sensitivity of our findings on conditions at the base of the ice sheet, which tend to affect ice speed sensitively, we look at four different cases of basal friction and use these to discuss what different bed friction means for where widening might occur and how pronounced it might be. We also discuss how our results could be tested against field data currently being acquired through the International Thwaites Glacier Collaboration.
There is an additional worry of trouble in East Antarctica after Kris Van Steenbergen provided satellite imagery of the Frost Glacier ice bridge breaking up near a steep slope on land. Unlike Thwaites, Frost glacier is above sea level, resting on the bedrock of East Antarctica. The Thwaites glacier is below sea level, where collapse would have a rebound effect in raising the sea level.
Frost glacier is part of the Porpoise Bay embayment. It is the largest glacier between the Cook-Ninnis-Mertz glacial system, which drains the Wilkes Subglglacial Basin and the Totten-MUIS (Moscow University Ice Shelf) glacial system, which drains the Aurora Subglacial Basin per Kris Van Steeben.
All of the below glaciers are at risk of collapse.
El Nino is likely to speed up Southern Ocean warming, exacerbating the melting of the Antarctic ice shelves.
EOS is one of the magazines of the American Geophysical Union They write:
When westerly winds weaken over the tropical Pacific Ocean, a string of weather extremes unfolds all over the globe, with impacts ranging from flooding in South American deserts to reduced monsoon rains in Indonesia and India. This shift in wind and water currents, known as the El Niño–Southern Oscillation (ENSO), will become more intense if global temperatures continue to rise.
Research now has revealed that projected changes to this global weather maker will also influence the remote Southern Ocean. Using the latest climate models, scientists have shown that enhanced El Niño events will likely speed the heating of deep-ocean waters around Antarctica, with the potential for accelerated melting of the continent’s land-held ice.
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The researchers found that an increase in ENSO variability over the next century will lead to changes in circulation in the Southern Ocean, causing accelerated warming of Antarctica’s deeper waters. The reason is that the slower westerly winds that blow over the region will reduce the upwelling of deep warm waters.
The analysis also showed that although the ocean surface will warm more slowly, the deeper ocean around Antarctica will warm more quickly, exposing the ice shelves that fringe the continent to heat from below.
These shelves do the important job of holding back glaciers on land. Deep-ocean warming could destabilize and melt the floating ice, allowing land-held ice sheets to slide more easily into the ocean, raising sea level. The researchers cannot say at this stage how deep-ocean warming will affect ice loss because the CMIP6 models don’t include interactive ice shelves or ice sheets