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

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

Subscribe to Geographical!

University of Winchester

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • The Human Game – Tackling football’s ‘slave trade’
    Few would argue with football’s position as the world’s number one sport. But as Mark Rowe discovers, this global popularity is masking a sinister...
    Essential oil?
    Palm oil is omnipresent in global consumption. But in many circles it is considered the scourge of the natural world, for the deforestation and habita...
    Mexico City: boom town
    Twenty years ago, Mexico City was considered the ultimate urban disaster. But, recent political and economic reforms have transformed it into a hub of...
    When the wind blows
    With 1,200 wind turbines due to be built in the UK this year, Mark Rowe explores the continuing controversy surrounding wind power and discusses the e...
    The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...

MORE DOSSIERS

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...

Geophoto

The recent heatwave had everyone longing for a drop of…

Wildlife

The demand for horseshoe crab blood – vital for testing…

Climate

One of the problems in getting accurate climate science out…

Wildlife

Italy is divided over the future of its wolves and…

Energy

A Scottish tidal power project in the Pentland Firth has…

Oceans

The world’s first full global analysis of beaches reveals the…

Geophoto

With the recent Saddleworth Moor fire, it can be easy…

Wildlife

Whale sharks have been found to not travel far from…

Wildlife

The Lone Star tick is spreading across North America, carrying…

Tectonics

Earlier this week, Indonesia was struck by a series of…

Energy

Efforts to reduce the energy drain of the internet are…

Energy

Coal’s rising popularity among climate-apathetic leaders is a worrying trend,…

Climate

Sharing the ideas of climate justice with a little humour…

Polar

Rising bedrock under the West Antarctic Ice Sheet could prevent…

Oceans

Officially declared the world’s ‘most overfished sea’, the Mediterranean is…

Wildlife

An interview with biologist Chris D Thomas, author of ‘Inheritors…

Geophoto

Some may see using the 50mm lens as a regressive…

Oceans

With the war against plastic gaining publicity and popularity, one…

Wildlife

India’s booming domestic dog population is attacking some of the…

Energy

Soaring sales of air conditioning units over the next thirty…