As per the new study, widespread melting of Antarctic ice sheets can possibly lead to sea-levels rising up to 20 metres. Antarctic ice sheets are capable of widespread melting under current atmospheric carbon dioxide levels, the study led by Victoria University of Wellington, New Zealand stated. Up to one-third of Antarctica’s ice sheets melted during the Pliocene epoch around three million years ago, the research stated. It caused sea-levels to rise as much as 25 metres above present levels. Carbon dioxide levels in the Earth’s atmosphere were similar to today’s levels and the temperature was two to three degrees Celsius warmer.
The study was led by Dr Georgia Grant, a PhD graduate from the Victoria University of Wellington. As part of her PhD research, Dr Grant developed a method to determine the magnitude of sea-level change through analysing the size of particles moved by waves. The method was applied to the geological archive from Whanganui Basin on the west coast of New Zealand’s North Island. Dr Grant showed in her research that global sea levels regularly fluctuated between 5 to 25 metres during the past warm period of the Pliocene about three million years ago.
"If we do not keep our greenhouse gas emissions in line with the Paris Climate Agreement target of two degrees warming, then we may potentially lose not only the West Antarctic Ice Sheet, but also the vulnerable margins of the East Antarctic Ice Sheet," said Professor Naish.
A critical concern is that over 90 per cent of the heat from global warming to date has gone into the ocean and much of it into the Southern Ocean which surrounds the Antarctic ice sheet, Dr Grant said raising concerns. One-third of Antarctica’s ice sheet sits below sea-level and is vulnerable to catastrophic collapse from ocean heating, the research shows.
"Our new study supports the idea that a tipping point may be crossed, if global temperatures are allowed to rise more than two degrees, which could result in large parts of the Antarctic ice sheet being committed to melt-down over the coming centuries. It reinforces the importance of the Paris target," said Dr Grant.
According to the research, the ice sheet melted in the past when atmospheric carbon dioxide levels were 400 parts per million, as they are today.