Our directory of things of interest

University Directory

Ice sheet melt rate underestimated

The West Antarctic Ice Sheet The West Antarctic Ice Sheet NASA
11 Mar
2015
The West Antarctic Ice Sheet contains enough ice to raise the global sea level by 16 feet, and it could be melting faster than previously thought

Researchers have long agreed that the vast West Antarctic Ice Sheet will collapse. Up until now the question has been whether it will take decades or centuries.

However, a new model from Caltech suggests that the collapse will come sooner than previously thought, with the potential to raise global sea levels by 16 feet.

Antarctica’s ice sheets are an unknown factor in global climate change. Scientists know that rising atmospheric and ocean temperatures damage the ice sheets, but nobody is sure how fast each sheet will melt.

Last year, a study suggested that the fastest possible melt rate would be 200 years with the slowest at more than a millennium, with 200–500 years being the most likely scenario.

‘All of our simulations show it will retreat at less than a millimetre of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go,’ said Ian Joughin, a glaciologist at the University of Washington, commenting on last year’s research.

us vs antarcticaUS and Antarctica compared (Image: NASA)

The new research shows the ice sheet’s physical features make it particularly vulnerable to global warming. The sheet’s grounding line, where the land ice meets the ocean, is particularly vulnerable.

‘Our results show that the stability of the whole ice sheet and our ability to predict its future melting is extremely sensitive to what happens in a very small region right at the grounding line,’ says Andrew Thompson, a co-author on the study.

A slope on the ocean floor directs warm water to the ice sheet’s base to melt the sheet from below.

Life on ice. A tour round the US Antarctic Program’s West Antarctic Ice Sheet base

The scientists think that as the grounding line retreats, interior ice flow into the oceans could increase. Grounding line recession also thins and melts ice shelves, which are floating extensions to an ice sheet that reduce ice flow into the sea.

Previous research took a simplified approach to measuring ice melt that did not account for friction at the grounding zone. The new model takes inspiration from earthquake research to improve predictions.

‘If another sudden switch happens in West Antarctica, sea level could rise a lot, so understanding what is going on at the grounding lines is essential,’ says Richard Alley, a glaciologist at Pennsylvania State University.

Once the new model has been applied to the ice sheet, scientists will be able to tell just how much sooner change will take place.

The research was published in the Journal of Glaciology. Read it here.

Related items

Subscribe and Save!

geo line break v3

Free eBooks - Geographical Newsletter

Sign up for our weekly newsletter today and get a FREE eBook collection!

geo line break v3

University of Winchester

geo line break v3

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The University of Derby

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Oceans

A ship that ran aground early in February has been…

Wildlife

Two whale populations on either side of the African continent…

Geophoto

March traditionally heralds the beginning of spring, a time of…

Wildlife

An innovative project to utilise Laos’ elephant experts in service…

Polar

Despite common belief that Antarctica is vastly uninhabited, humans are…

Wildlife

Javan rhinos survived the recent Krakatoa tsunami, but the species…

Energy

As the world turns away from fossil fuels, one question…

Geophoto

The winners of the Outdoor Photographer of the Year 2018…

Climate

New legislation in Florida aims to solve various environmental issues,…

Polar

The world’s magnetic model is getting an early update, as…

Climate

Marco Magrini looks at the financial pressures spilling out into the…

Geophoto

Few sights are more dramatic than a star-filled sky at…

Polar

A region of Antarctica previously known for relative stability is…

Tectonics

Everything we thought we knew about eruptions could be wrong

Oceans

Sea levels are rising across the globe, but along the…

Polar

Seismometers buried in the Ross Ice Shelf have revealed that…

Wildlife

A tightening of restrictions on the insecticides known as neonicotinoids…

Wildlife

Bonnethead sharks, the second smallest member of the hammerhead family,…

Nature

There’s more than enough plastic in the world. That’s why,…

Wildlife

The recent discovery of more than 200 million termite mounds…