The Cadman is a glacier that in 2017 was still known as a stable presence on the Antarctic continent. But recent research now shows that this is no longer the case; the Cadman Glacier appears to have transformed into an unstable glacier in a very short time.
Michael Meredith is a scientist who helped with the research, which was published in Nature Communications. He explains: “We have known for some time that the ocean around Antarctica is warming and that this could pose a major risk to glaciers and ice shelves. What this new research shows is that it is apparently possible for stable glaciers to become unstable almost without warning. This is dangerous, because from that moment on they suddenly become considerably thinner and lose large pieces of ice.”
Turned over
Anyway, from the beginning. Because what actually happened and why are scientists so shocked? In 2017, the Cadman Glacier was considered stable because it had a thick pillar of ice underwater that reached the bottom of the ocean. This ice pillar worked like an anchor, preventing ice from the glacier from easily floating into the sea. However, problems arose between 2018 and 2019, when a stream of unusually warm seawater deep below the surface found its way into the Cadman’s ice pillar. It is therefore during this period that the ice pillar finally breaks loose from the seabed, and can only sporadically exert its braking effect.
The ice pillar has now completely collapsed, and the glacier is melting twice as fast as normal. This has major consequences for the glacier itself, because it now loses 2.16 billion tons of ice every year and has to lose 20 meters in height. The most surprising thing, however, is that this entire process took exactly six years. Lead researcher Benjamin Wallis is therefore shocked: “We are surprised how quickly the Cadman has turned from a stable glacier to a glacier that is losing ice at a rapid pace.”
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Although the warm sea water is now causing the Cadman to melt rapidly, this is not the case with the neighboring glaciers Funk and Lever. The Wallis research team was mainly concerned with the question of why this was the case. It turns out: there is a group of undersea rocks and ridges that sends the warm sea water in a different direction. On the one hand, this is good news, but at the same time, according to the scientists, it shows how fragile the protection of the glaciers actually is. For example, further warming of the oceans could easily mean that these glaciers will no longer be safe.
The scientists conclude their research with a call to see the Cadman case primarily as an example of a glaciological tipping point. For example, they write in their research: “once past the tipping point, the Cadman lost 28% more ice in 13 months.” For now, the undersea rocks and ledges are still doing their job to spare Funk and Lever from a similar fate. However, we now also know: when they go, they go fast. Just like the Cadman.
2023-11-30 14:30:29
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