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Antarctica's Pine Island and Thwaites glaciers are tearing themselves apart, and it is horrifying.

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It is no surprise to those who follow the deglaciation process in Antarctica and are aware of the real threat posed by these glacial behemoths to human civilization. Rapid sea-level rise is likely when Pine Island and Thwaites (A/K/A The Doomsday glacier) glaciers collapse and take all of West Antarctica with them. These two glaciers hold 11 feet of sea-level rise.

Stef Lhermitte, an assistant professor at Geoscience TU Delft, shares his remarkable visuals of the ‘preconditioning’ currently in the process for eventual collapse. 

Due to the western wildfires and multiple hurricanes swirling in the Atlantic Basin, the climate crisis has broken through media outlets. They now report on the situation more than I can ever recall. Part of this current climate coverage was of these two glaciers that are crucial for the stability of West Antarctica.

We use satellite imagery to show how the shear margins of both @AntarcticPIG and @ThwaitesGlacier have weakened. Here you see a @NASA_Landsat🛰️ time lapse of @AntarcticPIG showing how the shear margin is tearing apart [2/n] pic.twitter.com/u7vRfFxcOH

— Stef Lhermitte (@StefLhermitte) September 14, 2020

From USA Today:

In the study, researchers combined satellite imagery from various sources to gain a more accurate picture of the rapid development of damage to portions of the ice shelves of Pine Island and Thwaites.

Ice shelves are permanent floating sheets of ice that connect to a landmass, such as Antarctica, according to the National Snow and Ice Data Center.

Ice shelves are the gatekeepers for glaciers flowing from Antarctica toward the ocean, according to NASA. Without them, glacial ice enters the ocean faster and accelerates the pace of global sea-level rise.

According to the study, the damage consists of crevasses and fractures in the glaciers, the first signs of the weakening process. Modeling has revealed that the emergence of this kind of damage initiates a feedback process that accelerates the formation of even more fractures and weakening.

More background and videos on the damage processes and why they matter on https://t.co/dmiObLInMW. Thx also to @Sainan_Sun@bert_polar@NASA_ICE@EtienneBerthie2@FrankPattyn@JanWuite@NASA_ICE@CopernicusEUpic.twitter.com/ENkLwE0htI

— Stef Lhermitte (@StefLhermitte) September 14, 2020

From the Proceedings of the National Acadamy of Sciences of the United States of America:

Pine Island Glacier and Thwaites Glacier in the Amundsen Sea Embayment are among the fastest changing outlet glaciers in West Antarctica with large consequences for global sea level. Yet, assessing how much and how fast both glaciers will weaken if these changes continue remains a major uncertainty as many of the processes that control their ice shelf weakening and grounding line retreat are not well understood. Here, we combine multisource satellite imagery with modeling to uncover the rapid development of damage areas in the shear zones of Pine Island and Thwaites ice shelves. These damage areas consist of highly crevassed areas and open fractures and are first signs that the shear zones of both ice shelves have structurally weakened over the past decade. Idealized model results reveal moreover that the damage initiates a feedback process where initial ice shelf weakening triggers the development of damage in their shear zones, which results in further speedup, shearing, and weakening, hence promoting additional damage development. This damage feedback potentially preconditions these ice shelves for disintegration and enhances grounding line retreat. The results of this study suggest that damage feedback processes are key to future ice shelf stability, grounding line retreat, and sea level contributions from Antarctica. Moreover, they underline the need for incorporating these feedback processes, which are currently not accounted for in most ice sheet models, to improve sea level rise projections.

We hypothesize that this damage preconditions these ice shelves for further disintegration. First, because it already compromises the integrity of both ice shelves. [4/n] pic.twitter.com/HqaPjg8OHv

— Stef Lhermitte (@StefLhermitte) September 14, 2020

An example of this preconditioning can be seen in the unprecedented retreat of the @AntarcticPIG ice shelf front over the last years where the ice shelf lost 30% of its area. [5/n] pic.twitter.com/cCccu3QQTS

— Stef Lhermitte (@StefLhermitte) September 14, 2020

Third, because the damage initiates a feedback process, where damage enhances speedup, shearing, and weakening, hence again promoting additional damage. [7/n] pic.twitter.com/zQ3gT7TCK6

— Stef Lhermitte (@StefLhermitte) September 14, 2020

To assess the importance of this damage feedback, we ran the BISICLES ice sheet model ice sheet model in an idealized setup with different weakening scenarios. [8/n] pic.twitter.com/wSWhz8UCxt

— Stef Lhermitte (@StefLhermitte) September 14, 2020

The model results highlight the importance of the damage feedback as a driver for ice shelf instability and grounding line retreat. E.g. the damage model runs result in a stronger grounding line retreat (up to 200%) than the model runs with only strong oceanic melting. [9/n] pic.twitter.com/qF18D9JrUe

— Stef Lhermitte (@StefLhermitte) September 14, 2020

Bonus: If you want to see how this damage looks like from an airplane? Check out this video made by @NASA_ICE on their Operation IceBridge flight over @AntarcticPIG in 2019 (https://t.co/ZfvskOQaYK) [The End / 12] pic.twitter.com/wMBlezw5zK

— Stef Lhermitte (@StefLhermitte) September 14, 2020

Like other recently discovered climate change phenomena, this discovery is not incorporated into current climate models.

Be sure to check out Stef, and his teams, work here. Fullscreen and crystal clear imagery. 

Wednesday, Sep 23, 2020 · 5:09:52 PM +00:00 · Pakalolo

Tonight!!

For an important perspective on the most crucial issue of our time, join @CE4Biden's event w/@SheldonforRI& Prof. @NaomiOreskes on #climate denial & critical need to elect @JoeBiden& @KamalaHarris. 23 Sept, 6 pm EThttps://t.co/5d0oFQhvry#science#ClimateWeek2020#ClimateWeekpic.twitter.com/mLxRPXCQwI

— A Siegel (@A_Siegel) September 22, 2020


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