Moderate warming could melt East Antarctic Ice Sheet

September 19, 2018

Parts of the world's largest ice sheet would melt if Antarctic warming of just 2°C is sustained for millennia, according to international research.

University of Queensland scientist Dr Kevin Welsh was part of a team that used evidence from warm periods in Earth's history to see how the East Antarctic Ice Sheet might react to a warming climate.

Dr Welsh said marine sediment layers indicated the ice sheet had retreated during warming in the late Pleistocene period, when temperatures were like those predicted for this century.

"Antarctica is around twice the size of Australia, with ice sheets several kilometres thick and containing around half of the world's fresh water," he said.

"The East Antarctic Ice Sheet covers about two thirds of the area, and because its base is largely above sea level it was generally thought to be less sensitive to warming climates than the adjacent West Antarctic Ice Sheet.

"However, some areas - like the Wilkes Land Subglacial Basin, directly south of Australia - are below sea level and contain enough ice to raise global sea levels by several metres.

"The evidence we have suggests that with the predicted 2°C warming in Antarctica - if sustained over a couple of millennia - the sheet would start melting in these locations."

Dr Welsh, from UQ's School of Earth and Environmental Sciences, said the team chemically analysed layers of sediment deposited on the Southern Ocean floor by glaciers.

"We found that the most extreme changes in the ice sheet occurred during two interglacial periods 125,000 and 400,000 years ago, when global sea levels were several metres higher than they are today," he said.

"These periods could be analogues for future climates and it seems likely that ice loss from the East Antarctic Ice Sheet contributed to those higher sea levels.

"Ice loss contributes to rising global sea levels which are a threat to many coastal communities, and making projections requires a solid understanding of how sensitive these ice sheets are."

Imperial College London researcher Dr David Wilson said the findings were extremely concerning for humanity.

"With current global temperatures already one degree higher than during pre-industrial times, future ice loss seems inevitable if we fail to reduce carbon emissions," Dr Wilson said.
-end-
The study was made possible by the International Ocean Discovery Program (IODP), part of the Australia and New Zealand IODP Consortium, funded by the Australian Research Council and other research organisations and universities in Australia and New Zealand, including UQ.

The scientific drilling ship JOIDES Resolution is funded by the US National Science Foundation.

University of Queensland

Related Ice Sheet Articles from Brightsurf:

Greenland ice sheet shows losses in 2019
The Greenland Ice Sheet recorded a new record loss of mass in 2019.

Warming Greenland ice sheet passes point of no return
Nearly 40 years of satellite data from Greenland shows that glaciers on the island have shrunk so much that even if global warming were to stop today, the ice sheet would continue shrinking.

Greenland ice sheet meltwater can flow in winter, too
Liquid meltwater can sometimes flow deep below the Greenland Ice Sheet in winter, not just in the summer, according to CIRES-led work published in the AGU journal Geophysical Research Letters today.

Ice sheet melting: Estimates still uncertain, experts warn
Estimates used by climate scientists to predict the rate at which the world's ice sheets will melt are still uncertain despite advancements in technology, new research shows.

Thousands of meltwater lakes mapped on the east Antarctic ice sheet
The number of meltwater lakes on the surface of the East Antarctic Ice Sheet is more significant than previously thought, according to new research.

Researchers discover ice is sliding toward edges off Greenland Ice Sheet
They found that ice slides over the bedrock much more than previous theories predicted of how ice on the Greenland Ice Sheet moves.

A clearer picture of global ice sheet mass
Fluctuations in the masses of the world's largest ice sheets carry important consequences for future sea level rise, but understanding the complicated interplay of atmospheric conditions, snowfall input and melting processes has never been easy to measure due to the sheer size and remoteness inherent to glacial landscapes.

Researchers discover more than 50 lakes beneath the Greenland Ice Sheet
Researchers have discovered 56 previously uncharted subglacial lakes beneath the Greenland Ice Sheet bringing the total known number of lakes to 60.

Ice-sheet variability during the last ice age from the perspective of marine sediment
By using marine sediment cores from Northwestern Australia, a Japanese team led by National Institute of Polar Research (NIPR) and the University of Tokyo revealed that the global ice sheet during the last ice age had changed in shorter time scale than previously thought.

Novel hypothesis goes underground to predict future of Greenland ice sheet
The Greenland ice sheet melted a little more easily in the past than it does today because of geological changes, and most of Greenland's ice can be saved from melting if warming is controlled, says a team of Penn State researchers.

Read More: Ice Sheet News and Ice Sheet Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.