Wednesday 10 August 2022 04:07 PM East Antarctic Ice Sheet could cause sea levels to rise by up to 16 FEET by ... trends now
An ice sheet that holds about 80 per cent of the world's glacier ice has the potential to cause global sea levels to rise by up to 16 feet (five metres) by 2500.
Scientists have predicted that melting of the East Antarctic Ice Sheet (EAIS) will result in this increase if temperatures continue to rise at the current rate.
This warming of about 0.32°F (0.18°C) per decade is the result of humanity's increase in greenhouse gas emissions since the Industrial Revolution.
Researchers from Durham University modelled the effects different temperatures and levels of emissions would have on the ice sheet in the next few centuries.
If no change is made to slow the warming, the EAIS could contribute up to ten feet (three metres) to global sea levels by 2300.
The melting could be limited significantly if emissions targets are met that see global temperature rise limited to 3.6°F (2°C) above pre-industrial levels.
The EAIS could then only contribute about 0.8 inches (two centimetres) of sea level rise by 2100, and 1.6 feet (0.5 metres) by 2500.
Thickness of ice in Antarctica, showing the location of the East Antarctic Ice Sheet (red outline), which holds the equivalent of 52 metres of sea level rise (alongside the UK and Ireland at the same scale). Wilkes Land (highlighted) has been referred to as East Antarctica’s ‘weak underbelly’, where some glaciers appear to be thinning, retreating and losing mass due to warm ocean currents
Scientists have predicted that melting of the East Antarctic Ice Sheet (EAIS) will result in this increase if temperatures continue to rise at the current rate. Pictured: Ice cliff at the terminus of Vanderford Glacier, Wilkes Land, East Antarctica
Previous periods of warming, that are similar to what the Earth is experiencing today, occurred over hundreds of thousands of years.
About 300,000 years ago, during the mid-Pliocene, temperatures were only between 1.3°F and 3.6°F (2°C and 4°C) higher than present.
This period of warming occurred gradually over 300,000 years and is thought to have been caused by changes in the way the Earth orbits the sun.
However, evidence of today's global warming indicates it just under 200 years ago.
The Earth's average surface temperature has increased rapidly by about 1.8°F (1.0°C) since the late 1800s.
This can be explained by the increase in our greenhouse gas emissions since the industrial revolution.
Lead author Professor Chris Stokes said: 'We used to think East Antarctica was much less vulnerable to climate change, compared to the ice sheets in West Antarctica or Greenland, but we now know there are some areas of East Antarctica that are already showing signs of ice loss.
'Satellite observations have revealed evidence of thinning and retreating, especially where glaciers draining the main ice sheet come into contact with warm ocean currents.
'This ice sheet is by far the largest on the planet, containing the equivalent of 52 metres of sea level and it's really important that we do not awaken this sleeping giant.'
Ice sheets in Greenland and West Antarctica were already predicted to lose ice in the centuries to come.
Greenland is far away from the North Pole so is exposed to warm air, and West Antarctica is affected by warm ocean currents as it sits below sea level.
However the EAIS is home to the staggeringly cold South Pole, and it is located on land that shields it from the sea's warmth, so it was widely assumed to be more solid.
But in 2020, evidence was found that a part of the EAIS retreated 435 miles (700 km) inland just 400,000 years ago - not that long ago on geological timescales.
This was in response to only 1.8-3.6°F (1-2°C) of warming.
In the study, published today in Nature, researchers from the UK, Australia, France and the USA examined how the EAIS responded to periods of warmth and high carbon dioxide concentrations in the past.
Around three million years ago, during the mid-Pliocene, temperatures were only between 3.6°F and 7.2°F (2°C and 4°C) higher than present.
This range of temperature change is one we could experience later this century.
However, global sea levels in the mid-Pliocene were between 33 and 82 feet (10 and 25 metres) higher than they are now.
Evidence from sea-floor sediments around East Antarctica indicates that part of the ice sheet collapsed and contributed several metres to this.