India News | Ice Sheets Capable of Collapse at a Much Faster Rate Than Known
Get latest articles and stories on India at LatestLY. Ice sheets are capable of retreating up to 600 metres a day during periods of climate warming, 20 times faster than the highest rate of retreat previously measured, and may last only for days or months, according to a new study.
New Delhi, Apr 6 (PTI) Ice sheets are capable of retreating up to 600 metres a day during periods of climate warming, 20 times faster than the highest rate of retreat previously measured, and may last only for days or months, according to a new study.
The international study, led by Christine Batchelor of Newcastle University, UK, used high-resolution imagery of the seafloor to find that a former ice sheet, that extended from Norway, underwent pulses of rapid retreat at a speed of 50 to 600 metres per day.
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This rate, the researchers said, is much faster than has been observed from satellites or inferred from similar landforms in Antarctica.
The former ice sheet retreated at the end of the last Ice Age, about 20,000 years ago.
The researchers have described their findings in the journal Nature.
The team, which mapped more than 7,600 small-scale landforms called 'corrugation ridges' across the seafloor, said that these landforms were understood to have formed when the ice sheet's retreating margin moved up and down with the tides, pushing seafloor sediments into a ridge every low tide.
The ridges are less than 2.5 metres high and are spaced between about 25 and 300 metres apart.
Given that two ridges would have been produced each day (under two tidal cycles per day), the researchers were able to calculate how quickly the ice sheet retreated.
"Our research provides a warning from the past about the speeds that ice sheets are physically capable of retreating at," said Batchelor.
Past behaviour of ice sheets helps inform computer simulations that predict future ice-sheet and sea-level change, the researchers said, and thus the value of acquiring high-resolution imagery about the glaciated landscapes preserved on the seafloor.
The study suggested that periods of such rapid ice-sheet retreat may only last for days or months.
"This shows how rates of ice-sheet retreat averaged over several years or longer can conceal shorter episodes of more rapid retreat," said study co-author professor Julian Dowdeswell, University of Cambridge, UK.
"It is important that computer simulations are able to reproduce this 'pulsed' ice-sheet behaviour," said Dowdeswell.
Batchelor and colleagues noted that the former ice sheet had retreated fastest across the flattest parts of its bed.
"An ice margin can unground from the seafloor and retreat near-instantly when it becomes buoyant," explained co-author Frazer Christie, University of Cambridge.
"This style of retreat only occurs across relatively flat beds, where less melting is required to thin the overlying ice to the point where it starts to float," said Christie.
The researchers conclude that pulses of similarly rapid retreat could soon be observed in parts of Antarctica, including those at West Antarctica's vast Thwaites Glacier, the subject of considerable international research due to its potential susceptibility to unstable retreat.
"Our findings suggest that present-day rates of melting are sufficient to cause short pulses of rapid retreat across flat-bedded areas of the Antarctic Ice Sheet, including at Thwaites," said Batchelor.
"Satellites may well detect this style of ice-sheet retreat in the near-future, especially if we continue our current trend of climate warming," said Batchelor.
(The above story is verified and authored by Press Trust of India (PTI) staff. PTI, India’s premier news agency, employs more than 400 journalists and 500 stringers to cover almost every district and small town in India.. The views appearing in the above post do not reflect the opinions of LatestLY)