The undersea ice anchors that help prevent Antarctica’s land ice from sliding into the ocean are shrinking at more than twice the rate of 50 years ago, research shows.

More than a third of these frozen moorings, known as pinning points, have shrunk in size since the turn of the century, experts say.

Scientists have warned that further deterioration of the pinning points, which hold the floating ice sheets that strengthen Antarctica’s land ice in place, will accelerate the continent’s contribution to sea level rise.

Floating ice sheets cover 75 percent of Antarctica’s coastline and cover an area the size of Greenland.

The findings are part of the first study of changes in the thickness of the Antarctic ice shelf — the extension of land ice that floats on the ocean — stretching back to 1973. Previous observations date back to 1992 only.

Researchers at the University of Edinburgh used satellite imagery from a fifty-year-old archive of the NASA/United States Geological Survey (USGS) Landsat program to trace variations in the appearance of pinning points on the ice surface.

Pinning points are formed when part of a floating ice sheet anchors itself high on the ocean floor, creating a pronounced bump on the surface of an otherwise smooth ice shelf.

Using changes in pinning points as a reliable proxy for changes in ice shelf thickness, the team measured changes in these properties over three time periods: 1973 to 1989, 1990 to 2000, and 2000 to 2022. .

The scientists found that between 1973 and 1989, only 15 percent of pinning points decreased in size, causing small localized pockets of ice shelf thinning.

However, in the 1990s, large-scale acceleration and drift of ice shelves from pinning points began in the West Antarctic Peninsula and Amundsen Sea.

The number of pinning points increased to 25% from 1990 to 2000 and 37% from 2000 to 2022.

Newspaper, published in The naturewas funded by the Leverhulme Trust.

Lead author, Dr Bertie Miles, Liver Holme Early Career Fellow, School of Geosciences, University of Edinburgh, said: “Relatively limited and regionally concentrated ice shelf melting over the past 50 years has resulted in much more widespread disarray. The shift toward being, is staggering. The ongoing concern is how many of these tipping points will begin to melt over the next 50 years.”

Co-lead author Professor Robert Bingham, Professor of Glaciology and Geophysics, School of Geosciences, University of Edinburgh, said: “What we’re seeing around Antarctica is a sustained onslaught of climate warming. , which slows the rate of ice melt. Global sea level rise. This reinforces the need for us to take steps where we can to reduce global carbon emissions. “