Even moderate warming could melt the Antarctic ice cap: study

A moderate increase in global temperature of just two degrees Celsius could still be enough to melt parts of the Earth's largest ice sheet and raise sea levels by several meters, experts said Wednesday.

As the pace of climate change quickly surpasses mankind's attempts to control it, scientists have plunged into the distant past of the glaciers of eastern Antarctica to predict what was happening as our planet was warming up.

Until now, the attention of climate experts was mainly focused on the ice caps in the West of Antarctica, many of which are located below sea level and contribute to most of the melting ice on the continent.

But parts of the East Antarctic Ice Sheet – the largest in the world, containing about half of the Earth's freshwater – also lie beneath the line of Flotation of the ocean, which makes it particularly vulnerable to rising temperatures.

A study published by Nature on Wednesday analyzed the layers of ocean floor sediments deposited the last time the Wilkes subglacial basin, located in southern Australia, melted about 125,000 years ago.

The experts estimated that a sustained temperature rise of only 2 ° C – the ceiling set in the historic Paris Framework Agreement to prevent global warming – would be needed for the Wilkes Basin to melt again.

"This is the first time we see direct evidence of how this part of the ice sheet has undergone a fairly moderate warming in the geological past," said AFP's David Wilson. Imperial College and senior author of the study.

"The extent of the changes will depend this time on the magnitude of the warming, but by 2 ° C, you will see changes."

The team found that if global temperatures were maintained at 2 ° C above pre-industrial levels for several hundred years, the entire basin would melt, causing the global sea level to rise by about 4 meters.

This would endanger small island nations and make hundreds of millions of people uninhabitable on the coast.

Under the current emission levels, the Earth would warm well beyond 2 ° C at the end of the century, even 4 to 5 ° C.

"The loss of ice contributes to rising sea levels globally, posing a threat to many coastal communities," said Kevin Walsh of the University of Queensland, who worked on the study.

– "Loss of ice inevitable" –

Walsh and his team studied ice-age sediment samples from 450,000 years ago, at times when the global sea level was several meters higher than it is now.

"These periods could be similar for future climates and it seems likely that ice loss from the East Antarctic ice sheet contributed to these higher levels of the sea", he declared.

The Paris agreement, concluded between nations in 2015, aims to limit global temperature increases to "well below 2C – and 1.5C if possible".

But scientists are still catching up with the mass emissions of fossil fuels emitted into the atmosphere since the industrial era on the planet.

While the Earth has experienced several periods during which temperatures were warmer than today, Wilson said that climate change caused by humans was a different proposition.

"The time scale of interglacial cycles was tens of thousands of years … today we are talking about conditions that could be reached by the end of the century," he said.

"With current global temperatures already one step ahead of pre – industrial levels, future ice loss seems inevitable if we fail to reduce carbon emissions.

Until now, the attention of climate experts was focused mainly on the ice caps in the western Antarctic, many of which lie below sea level and contribute to most of the melting ice on the continent.