Irreversible danger of impending destruction of Antarctic ice sheet voiced

The West Antarctic Ice Sheet, which contains around 750,000 cubic miles of ice – enough to fill Wembley Stadium nearly 3 billion times – is a rich reservoir of precious frozen freshwater. Now scientists are warning that the vast natural feature is on the brink of catastrophic “irreversible” collapse. The collapse would cause a devastating rise in sea levels worldwide of up to 4 metres over the next few hundred years, experts say.

And it could be caused by ocean warming only slightly faster than we currently see, writes the Daily Mail.

"Even a modest warming of 0.25°C above present levels in the deep ocean could trigger the onset of collapse," warns study author David Chandler of the Norwegian Research Centre for Climate Change (NORCE). "In our current climate, the transition to a collapse state would be slow, perhaps over 1,000 years, but would likely happen much faster if there were additional global warming."

In the future, as sea levels rise, large towns and villages will be flooded, meaning people will have to abandon their homes and move inland. And small island nations could gradually become completely submerged, forcing their residents to emigrate, writes the Daily Mail.

Ice sheets are masses of ice sheet covering an area of ​​more than 50,000 square kilometres. There are two ice sheets on Earth – the Greenland and Antarctic – and together they contain around 99% of the Earth’s fresh water, the Daily Mail explains. As its name suggests, the West Antarctic Ice Sheet is the western segment of the latter and is more exposed to the effects of climate change. Unlike its eastern counterpart, the West Antarctic Ice Sheet lies mostly on the seabed. In other words, the West Antarctic ice sheet is covered in water, and today that water is getting warmer and warmer due to global warming.

"Both East and West Antarctica have very thick ice - more than 3km thick, and at its thickest point 4.9km," Chandler told MailOnline. "West Antarctica is important for two reasons: firstly, if even a small part of all that ice melted, it would cause a catastrophic rise in sea levels. Secondly, the ice sheet itself affects the climate, so if some of it melted, it could cause climate change as far away as Europe."

The research team, which also included experts from academic institutions in the UK and Germany, ran model simulations of glacial cycles over the past 800,000 years. During this period, the Earth's climate has alternated several times between cold periods known as "glacials" and warmer periods called "interglacials".

Some of these past interglacial periods were likely warmer than our modern climate, and provide insight into how the vast Antarctic ice sheet might respond to future warming.

During interglacial periods, warm ocean water would melt and thin the floating ice shelves that surround and protect the West Antarctic Ice Sheet, leaving it vulnerable.

"Over the last 800,000 years, the Antarctic ice sheet has had two stable states, between which it has changed several times," Chandler said. "One of them, the West Antarctic Ice Sheet, is in the state we're in now. The other state was the collapse of the West Antarctic Ice Sheet. Because the heat needed to melt the ice in Antarctica comes mostly from the ocean, there's now concern that warming waters from climate change will cause the West Antarctic Ice Sheet to collapse again."

The loss of ice from this "massive reservoir of fresh water" could threaten coastal communities and the global economy if the ice volume decreases by just a few percent.

Once the ice sheet reaches a collapsed state, it will take several thousand years of relatively low temperatures (at or below pre-industrial conditions) to return to a stable modern state.

"Once the overturning occurs, it becomes self-sustaining and it appears very unlikely that it will be stopped before it causes sea level rise of about four metres - and that would be virtually irreversible," Chandler said.

In 2023, British Antarctic Survey (BAS) experts said the rate of melting of the West Antarctic ice sheet would continue to increase until the end of the century, no matter how much we cut our use of fossil fuels.

Even if greenhouse gas emissions are controlled to achieve the best possible scenario, ice sheet melting will continue to accelerate this century, three times faster than in the 20th century, the BAS team found.

If the ice sheet were to melt completely, it would release enough water to raise sea levels worldwide by 5.3 metres. However, scientists say this would "only" add one metre to their rise by the end of the century.