The "Doomsday Glacier" is rapidly melting. Scientists now have evidence of when and why
Scientists have turned back in time to reconstruct the past life of the "Doomsday Glacier" in Antarctica, nicknamed as such because its collapse could trigger a catastrophic rise in sea levels.
They found that the glacier began melting rapidly in the 1940s, according to a new study that provides an alarming perspective on future melting, as reported by CNN.
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The Thwaites Glacier in West Antarctica holds the title of being the world's largest glacier, approximately equivalent in size to the state of Florida. Researchers were aware that it had been experiencing an increased ice loss since the 1970s, but due to the limited timeframe covered by satellite data, the precise onset of significant melting remained unknown.
Now there is an answer to that question, according to a study published on February 26 in the Proceedings of the National Academy of Sciences.
Analyzing marine sediment cores extracted from the ocean floor, researchers found that the glacier began retreating significantly in the 1940s, likely triggered by a very strong El Niño event — a natural climate fluctuation that tends to have a warming impact.
Since then, the glacier has failed to recover, reflecting the increasing impact of human-caused global warming, according to the report.
What happens to Thwaites will have global repercussions. The glacier already contributes to a 4% rise in sea levels, shedding billions of tons of ice into the ocean each year. Its complete collapse could increase sea levels by more than 2 feet.
However, it also plays a crucial role in the stability of the West Antarctic Ice Sheet, acting as a plug that stops the vast expanse of ice behind it from spreading. Thwaites' collapse would undermine the stability of the glacier, which contains enough water to raise sea levels by at least 10 feet, causing catastrophic global flooding.
The study's findings align with previous research on the neighboring Pine Island Glacier, one of the largest ice streams in Antarctica, which also began melting rapidly in the 1940s.
This makes the research significant, said Julia Wellner, associate professor of geology at the University of Houston and one of the study's authors. She told CNN that what is occurring with Thwaites is not unique to a single glacier, but is part of the larger context of a changing climate.
To build a picture of Thwaites' life over the past almost 12,000 years, scientists took a research vessel close to the glacier's edge to collect ocean sediment cores from various depths.
These cores provide a historical timeline. Each layer provides information about the ocean and ice thousands of years ago. By scanning and dating the sediments, scientists were able to identify when significant melting began.
Based on this information, they believe Thwaites' retreat was triggered by an extreme El Niño event that occurred at a time when the glacier was likely already in a melting phase, tipping it into imbalance.
The conclusions are alarming because they suggest that once major changes are triggered, it is very difficult to stop them, said James Smith, a marine geologist at the British Antarctic Survey and co-author of the study.
Although similar retreats occurred much further in the past, the ice cap recovered and grew again, Smith said. But these glaciers "show no signs of recovery, likely reflecting the increasing influence of human-caused climate change".
