Could the Antarctic ice sheet melt? “It has weakened by 450 meters in 200 years.” Horrific study in nature

The ice sheet in West Antarctica has suddenly shrunk dramatically. This emerges from new research by Nature Geoscience: The evidence comes from the analysis of a semicircular section of ice – about 600 meters long – obtained through core drilling of glaciers or polar ice caps, a technique capable of providing useful information about the world's climate. past. The study raises alarm bells: part of the ice sheet has already diminished by 450 meters in just 200 years. This is the first research showing rapid and obvious ice loss in Antarctica.

“We were able to tell exactly when the ice retreated, but we were also able to see how quickly it retreated,” Eric Wolf, a glaciologist at the University of Cambridge and author of the study, told CNN. The danger is that it could happen again: “If it happens, it will happen very quickly,” Wolff added. The consequences could be catastrophic due to global sea level rise. In fact, the West Antarctic ice sheet contains enough water to raise sea levels by about 5 metres, causing devastating flooding in coastal cities around the world. “The amount of ice stored in Antarctica can change very quickly, at a pace that is difficult for many coastal cities to manage,” Ted Scambos, a glaciologist at the University of Colorado Boulder, told CNN.

Ice cores—sections analyzed through subterranean drilling—serve as historical archives of Earth's atmosphere: they consist of layers formed as snow falls and compresses over thousands of years and contain bubbles from ancient times and contaminants that provide documentation of environmental changes that have occurred over the course of thousands of years. thousands of years. The section analyzed in the nature study was excavated by the Ice Rise Skytrain located at the edge of the ice sheet. Scientists extracted it in 2019, in a painstaking process that included continuous drilling over a period of 40 days, carried out by lifting a thin cylinder of ice a few meters at a time. They then cut the core into sections, which were packed into insulated boxes kept at minus 20 degrees Celsius and sent to the UK, where scientists measured water isotopes, which provide information about past temperatures. They also measured the pressure of air bubbles trapped in the ice. The data revealed that the ice thinned very quickly at the end of the last ice age.

The study is crucial to improving the accuracy of models that scientists use to predict how the ice sheet will respond to global warming in the future. David Thornalley, an oceanographer and climate scientist at University College London, said the study's data was “astonishing.” He cautioned that because they examined a period 8,000 years ago, when climate conditions were different, the results are not a direct example of what might happen today. But he added that they could provide “insight into how ice sheets collapse.”

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