Antarctica’s ‘doomsday glacier’ began melting in mid-20th century: Study

West Antarctica’s Thwaites Glacier — often known as the “doomsday glacier” due to the potentially catastrophic consequences of its hypothetical collapse — began rapidly retreating at an earlier date than scientists had previously known, according to a study published Monday.

Published in the Proceedings of the National Academy of Sciences, the study used new satellite technology to conclude the rapid melting of the glacier likely began in the 1940s.

While scientists had already observed the glacier’s accelerated retreat by the 1970s, they did not know when it began.

Coupled with earlier research about Thwaites’s neighboring Pine Island Glacier, the study also provides new, potentially alarming, insight into the cause of the glacier’s melting.

Scientists tried to reconstruct the glacier’s history using analysis of the marine sedimentary record, and they found the Thwaites and Pine Island glaciers both lost contact with the seafloor highs in the 1940s — at around the same time.

These significant changes happened against the backdrop of a massive El Niño weather phenomenon, the scientists found, showing the glaciers “were responding to the same driver(s).”

“The synchronous ice retreat of these two major ice streams suggests that, rather than being driven by internal dynamics unique to each glacier, retreat in the Amundsen Sea drainage sector results from external oceanographic and atmospheric drivers, which recent modelling studies show are modulated by climate variability,” the study read.

The scientists note that the glaciers’ continued retreat shows how difficult it can be to reverse some of the consequences of naturally occurring weather events — which they say is made even more difficult by human activity.

“That ice streams such as Thwaites Glacier and Pine Island Glacier have continued to retreat since then indicates that they were unable to recover after the exceptionally large El Niño event of the 1940s,” the scientists wrote.

“This may reflect the increasing dominance of anthropogenic forcing since that time but implies that this involved large-scale, in additional to local, atmospheric and ocean circulation changes.”