Antarctic ice can melt 20 times faster than we thought

A warning for contemporary global warming is included in a recent study of one of the largest ice sheets from the previous Ice Age.

Antarctica's melting ice sheets may disappear considerably more quickly than previously imagined. According to a research published on April 5 in the journal Nature, the Eurasian Ice Sheet retreated up to 2,000 feet per day in certain places during the end of the last Ice Age. Compared to earlier data, this pace is 20 times quicker. Even the glaciers in Antarctica that are thought to move as swiftly as 160 feet per day are outpaced by these changes by a wide margin.

The new discoveries could be very important for comprehending the current ice loss.

The third-largest ice sheet during the previous Ice Age, the Eurasian Ice Sheet, receded from Norway around 20,000 years ago. It stretched out to approximately 3,000 kilometers at its widest point. The ice sheets in Greenland and Antarctica, which have lost more than 6.4 trillion tons of ice over the last thirty years, reflect these retreats. More than one-third of the overall sea level increase is attributable to both of these contemporary ice sheets.

According to Newcastle University physical geographer and study co-author Christine Batchelor, "this research presents a warning from the past about the rates that ice sheets are physically capable of receding at." Our findings indicate that bursts of fast retreat may occur much more quickly than previously seen.

High-resolution images of the seabed were utilized by an international team of researchers to examine how the ice sheet transitioned for this study. In the area where the ice sheet formerly existed, they sketched out more than 7,600 tiny structures known as "corrugation ridges" on the ocean floor. The ridges are 82 to 984 feet apart and have a height of less than eight feet. These ridges are thought to have developed as a result of the retreating ice sheet's edge moving with the tide. Every low tide, sediments from the seafloor are forced into a ridge, therefore two ridges would have formed throughout two daily tidal cycles. The crew was able to determine the massive retreat speed because to the spacing.

Such information on the previous responses of ice sheets to warming may be used to guide computer models that forecast future ice-sheet and sea-level change. It also implies that these bursts of fast melting may only last a few days to months, which is a brief amount of time in the context of geology.

This demonstrates how rates of ice-sheet retreat that are averaged over many years or more can mask shorter episodes of more rapid retreat, according to research co-author and glaciologist Julian Dowdeswell of the University of Cambridge. It's crucial that computer simulations can capture the dynamics of this "pulsed" ice-sheet.

Studying these formations on the ocean floor also demonstrates the mechanisms underlying the fast ice retreat. According to co-author and Cambridge glacial geophysicist Frazer Christie from Scott, the study discovered that the old ice sheet receded more along the flattest portion of its bed where "less melting is necessary to thin the underlying ice to the point where it starts to float." "As it becomes buoyant, an ice edge can unground from the bottom and recede almost immediately."

The research team predicts that some regions of Antarctica, notably the enormous Thwaites Glacier in West Antarctica, could eventually see pulses of comparable rapid retreat. As Thwaites, often known as the "Doomsday Glacier," has lately retreated close to a flat portion of its bed, it may experience a similar pulse of rapid glacier retreat.

According to Batchelor's research, sudden bursts of fast retreat can be caused by the Antarctic Ice Sheet's current melting rates in flat-bedded regions, notably at Thwaites. In the near future, satellites "may well detect this sort of ice-sheet retreat," particularly if the current pattern of climatic warming is maintained.