Thwaites Glacier In Bigger Trouble Than Thought: More Ocean Infiltration, Greater Instability

[hatrack]

“We might (and I stress might) have already reached and passed a point where there is really no turning back for Thwaites, no matter what we as humans do to our climate,” Alastair Graham, the University of South Florida and co-author of the study.


New data from under the ice stream at Thwaites glacier, commonly referred to as the doomsday glacier, in West Antarctica found the Florida-sized glacier is being assaulted by warm ocean water wherever it contacts the ice. Particularly alarming is that the phenomenon includes clear weakening of the glacier's pinning points - where the ice meets the bedrock that provides stability for much of West Antarctica’s floating ice shelves. This is dire news for the world's coastlines as ten feet of abrupt sea-level rise could happen sooner than anyone had dared to imagine. The data research, published in Scientific Advances, was obtained by an uncrewed submarine. It identifies new pathways and modifications of warm ocean water under Thwaites.

EDIT

The new study is based on field observations from 2019 when a team of two dozen scientists sent an autonomous orange submarine named Ran down underneath Thwaites. For 13 hours, the underwater vehicle traveled around two deep troughs beneath the glacier that funnel warm water toward it. As it did, the vehicle captured data showing that warm water—warm for a glacier, at up to 33.89 degrees Fahrenheit (1.05 degrees Celsius)—is swirling around the glacier’s crucial “pinning points,” or the points of contact where the ice shelf meets the bedrock that holds it in place. This warm water is melting away these crucial holds, making room for cracks and troughs in ice that can make the shelf all the more unstable.

EDIT

“The worry is that this water is coming into direct contact with the underside of the ice shelf at the point where the ice tongue and shallow seafloor meet,” Alastair Graham, associate professor of geological oceanography at the University of Southern Florida and study co-author, who was on the research expedition to the glacier, wrote in an email. “This is the last stronghold for Thwaites and once it unpins from the sea bed at its very front, there is nothing else for the ice shelf to hold onto. That warm water is also likely mixing in and around the grounding line, deep into the cavity, and that means the glacier is also being attacked at its feet where it is resting on solid rock.”

EDIT

https://www.dailykos.com/stories/2021/4/9/2025169/-Thwaites-glacier-is-in-extreme-peril-as-warm-water-is-discovered-eroding-critical-pinning-points

[Random Boomer]

1. Where have I heard this before?

...ten feet of abrupt sea-level rise could happen sooner than anyone had dared to imagine.

We (humans) appear to be suffering from extraordinarily impaired imagination because we persist in being surprised by the rapidity of climate change. I've been hearing the "faster than expected" mantra for two decades now, and I, for one, am no longer the least bit surprised.

[pscot]

2. I'm old enough to remember

being happily unaware of the troubled state of Antarctica's glaciers.