ANTARCTICA: The annual melting of ice in Antarctica is faster than ever, about six times more than forty years ago, resulting in an ever-increasing rise in ocean levels, scientists warned on Monday.
The waning ice of the White Continent is responsible for a 1.4-centimetre rise in the level of the world’s oceans between 1979 and 2017, according to a report from the Proceedings of the American Academy of Sciences (PNAS).
And the expected rate of melting should lead to a disastrous rise in this level in the coming years, noted Eric Rignot, president of the Chair of Earth Science System at the University of California (Irvine).
“With the Antarctic ice cap continuing to melt, we expect the ocean level to rise several meters because of Antarctica in the next centuries,” he added.
According to previous studies, a rise of 1.8 meters by 2100 – one of the worst scientific predictions – would flood many coastal cities with millions of people around the world.
For this new study, whose findings are published Monday, the researchers conducted the longest ice mass assessment in eighteen Antarctic regions.
They used data provided by high-resolution aerial photographs taken by NASA aircraft, as well as radar images from satellites of multiple space agencies.
They found that between 1979 and 1990, Antarctica lost an average of 40 billion tonnes of ice mass per year. From 2009 until 2017, it has increased to 252 billion tonnes each year.
More worryingly, scientists have identified areas in the east that were once considered relatively “safe from change”, unlike those in the west, but are now losing much ice.
“The Wilkes land area in eastern Antarctica has, overall, made a significant contribution to mass loss even as far back as the 1980s,” said Rignot.
“This region is probably much more sensitive to climate than was traditionally presumed and it is important to know because it has more ice than West Antarctica and the Antarctic Peninsula combined,” he said. he continued.
Antarctica contains enough ice to cause, if it melts completely, a rise of 57 meters of the sea level.
The vast majority of the ice is concentrated in the East Antarctic, with enough to raise the seas 52 meters in case of melting, against 5 meters for the western part.
The East Antarctic Ice Sheet, the largest in the world, contains about half of the world’s freshwater reserves.
A baseline study published in June 2018 in the journal Nature reported that the melting of Antarctic ice had tripled since 1992, but showed no significant impact in the East.
However, another major study analyzed three months later, in the same review, layers of seabed sediments deposited during the last melting of Wilkes subglacial basin in East Antarctica. is 125,000 years old.
This study showed that this huge pool would begin to melt again when the temperature rises 2 ° C, the high limit set by the Paris agreement to mitigate climate change.
Recent research should encourage “increased attention” to ice melt in eastern Antarctica, the PNAS report said.
Scientists say warming ocean water will accelerate melting even further, and sea levels will continue to rise for centuries, no matter what efforts are being made to combat climate change.
Their temperature, have shown recent studies, is warming faster than scientists thought and have reached new records in recent years.