The Cadman River is a glacier that in 2017 was still known to have a stable presence in Antarctica. But recent research now shows that this is no longer the case; Cadman Glacier appears to have turned into an unstable glacier in a very short time.
Michael Meredith is a scientist who helped with the research 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 danger 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 point on they suddenly become considerably thinner and lose large chunks of ice.
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Anyway, from the beginning. Because what really happened and why were scientists shocked? In 2017, Cadman Glacier was considered stable because it has a thick column of underwater ice that reaches the ocean floor. This ice column served as an anchor, preventing the ice from the glacier from easily floating out to sea. However, problems arose between 2018 and 2019, when a stream of unusually warm seawater deep beneath the surface found its way into the Cadman Ice Column. Therefore, during this period, the ice column finally breaks off from the seafloor, and can only exert a braking effect intermittently.
The ice column has now completely collapsed, and the glacier is melting twice as fast as usual. This has serious consequences for the glacier itself, because it is now losing 2.16 billion tons of ice every year, and must lose 20 meters in height. But what is most surprising is that this whole process took exactly six years. So, lead researcher Benjamin Wallis is shocked: “We are amazed at how quickly the Cadman River has gone from a stable glacier to a glacier that is rapidly losing ice.”
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Although warm sea water is now causing the Cadman River to melt rapidly, this is not the case with the neighboring Funk and Lever glaciers. Wallis’ research team was primarily interested in the question of why this happens. It turns out that there is a group of rocks and ridges under the sea’s surface that send warm sea water in a different direction. On the one hand, this is good news, but at the same time, according to scientists, it shows how fragile the protection of glaciers actually is. For example, further ocean warming may mean that these glaciers will no longer be safe.
The scientists concluded their paper with a call to look at the Cadman case primarily as an example of a glacial tipping point. For example, “once the tipping point was passed, Cadman lost 28% more ice in 13 months,” they wrote in their paper. For now, 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 Cadman.
