The Thwaites Glacier, ominously nicknamed the "Doomsday Glacier," has been under the watchful eye of scientists who have been probing its depths with ice-breaking ships and underwater robots. Their findings, published in a series of studies, paint a bleak picture of the glacier's future, with the potential to significantly raise global sea levels.

Since 2018, the International Thwaites Glacier Collaboration has been conducting an in-depth study of this glacier, which could be on the brink of an irreversible collapse. The research, spanning six years, has revealed that the glacier's retreat has been accelerating over the past three decades, and the rate of ice loss is expected to increase further this century.

The implications are dire: Thwaites holds enough water to raise sea levels by over two feet, but its role as a buffer for the larger Antarctic Ice Sheet means that its collapse could lead to a catastrophic ten-foot rise in sea levels. This would have profound impacts on coastal communities worldwide, from Miami and London to Bangladesh and the Pacific Islands.

The glacier's vulnerability is partly due to its geographical setting, with the land it sits on sloping downward, exposing more ice to warmer ocean waters as it melts. However, the detailed mechanisms of its retreat were previously not well understood.

To shed light on this, scientists have employed a range of innovative methods. They have sent a torpedo-shaped robot, Icefin, to the glacier's grounding line, where the ice meets the sea, a critical point of vulnerability. The images captured by Icefin have shown that the glacier is melting in unexpected ways, with warm ocean water finding its way through deep cracks and "staircase" formations in the ice.

Additional studies using satellite and GPS data have highlighted how tides can push seawater miles beneath Thwaites, causing rapid melting. Meanwhile, by analyzing marine sediment cores, researchers have reconstructed the glacier's past and discovered that it began to retreat rapidly in the 1940s, likely due to a strong El Niño event.

While there is concern about the potential for rapid melting if Thwaites' ice shelves collapse, computer modeling has shown that this process, while real, is less likely than previously thought. However, this does not mean that Thwaites is out of danger. The scientists predict that the entire glacier and the Antarctic Ice Sheet behind it could be gone by the 23rd century.

Despite the progress made, there remains a deep uncertainty about the future of this glacier. Even if we were to cease burning fossil fuels immediately, it may already be too late to save Thwaites. The International Thwaites Glacier Collaboration has concluded this phase of their project, but they emphasize that further research is essential to fully understand this complex glacier and to determine whether its retreat is now irreversible. The fate of the Doomsday Glacier hangs in the balance, a stark reminder of the fragility of our planet's icy sentinels.