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Thwaites Glacier. This is what melting Antarctica looks like up close. Doom Glacier ‘still in trouble’ [WIDEO]

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The Thwaites Glacier, also known as the Doom Glacier, is melting in a completely different way than predicted. Using a remote-controlled camera, scientists have peered beneath the surface of a giant ice mass in Antarctica, discovering cracks and undercuts where the glacier’s mass loss is rapid.

The Antarctic Thwaites Glacier covers an area of ​​192,000 square kilometers, which is almost two-thirds of Poland. This gigantic structure is particularly vulnerable to climate change and rising ocean temperatures. Melt from the Thwaites Glacier is estimated to account for about four percent of annual sea level rise. Scientists from the International Thwaites Glacier Collaboration (ITGC) project investigated how melting occurs and the results have been published in Nature.

Steps and cracks

To look under the 600-meter-thick ice sheet, the researchers cut a hole in it. It was located close to the grounding line – the border of contact between the base of the glacier and the land, beyond which it floats on the surface of the water. In this way, scientists were able to introduce the Icefin robot – a remote-controlled camera – under the ice. The researchers measured the rate of melting in this zone and compared it with data from five other points below the ice.

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During the nine-month study, the ocean near the ground line became warmer and saltier, but the rate of melting at the base averaged 2-5 meters per year less than climate modelling. The ice is protected by a layer of fresher water that acts as a buffer. However, scientists noticed a disturbing regularity – the melting processes led to the undermining of the shelf in the shape of giant steps. In these places, as well as in cracks and fissures, it occurs extremely quickly.

“The glacier is still in trouble,” explains Peter Davis of the British Antarctic Survey, one of the study’s authors. – Despite the relatively small amount of melting, the ice is retreating quickly, so it doesn’t take much to throw it off balance.

Icefin camera under the iceRob Robbins, USAP Driver/ITGC

The weakest points of the glacier

Britney Schmidt of Cornell University, one of the authors of the study, adds that new ways of observing glaciers allow us to understand that it matters not only how fast the melting progresses, but also where.

– Such cracks and steps are observed in warming glaciers. Warm water gets into the cracks, washing away the ice at its weakest points, he points out.

Heat and salt can be transferred deep into the Thwaites Glacier through fissures, widening existing gaps in the ice. Worryingly, major fractures are progressing across the ice shelf, and their continued weakening may eventually lead to it breaking off.

The Thwaites Glacier is one of the fastest changing glaciers in Antarctica. Its ground-level zone, where the ice meets the seabed, has retreated 14 kilometers since the late 1990s. Much of the cover is below sea level and is prone to rapid melting, which could raise global sea levels by more than half a meter over the course of centuries.

Cracks in Thwaites Glacier, 2020Icefin/ITGC/Schmidt

Thwaites Glacier research station, 2022Peter Davis/British Antarctic Survey/ITGC

Science Alert, The International Thwaites Glacier Collaboration

Main photo source: Icefin/ITGC/Schmidt/Washam

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