A chilling message: Ice sheets melting three times faster than 20 years ago

New research using satellite measurements shows polar caps are shrinking three times quicker than 20 years ago

The polar ice sheets are melting three times faster than they were 20 years ago, according to satellite measurements.

More than 4,200 gigatonnes were lost from the polar ice sheets from 1992 to 2011, an average of 223Gt a year and rising.

Researchers described the losses as being at “the high end” of forecasts by the Intergovernmental Panel on Climate Change (IPCC) in 2007.

The findings are based on previous  satellite readings but have been combined and correlated to provide what scientists believe is “the most accurate assessment” yet of polar ice loss.

Accurate calculations of how much ice is lost from Greenland and Antarctica are notoriously difficult.

In 2007, the IPCC wasn’t even sure if there was a net loss or gain.

Professor Andrew Shephard, of the University of Leeds, said it was “two or three times” more accurate than previous assessments. He said the implications were serious: “The ice sheets used to be a minor player in sea-level rise. Now they seem to be a substantial player.”

It provides “baseline” data which will make future forecasts of ice loss and sea-level rises much more accurate.

Net losses of ice contribute to sea- level rises and the study found that the rate has increased significantly in only 20 years. During the 1990s, ice sheet loss accounted for 10 per cent of sea- level rises but in the past five years it has risen to more than 30 per cent.

Melting ice caps, the new calculations show, caused 11mm of the overall rise since 1992 but the rate of loss is increasing rapidly. In the 1990s, 0.27mm of annual sea-level rise was blamed on polar melting, whereas in the past five years it has risen to 0.95mm annually.

Melting of ice in Greenland has had the biggest impact, contributing 7.4mm to sea-level rises since 1992. Antarctica has contributed 3.7mm but there are clear regional differences. While West Antarctica has lost an average 65Gt annually and the Antarctic Peninsular 20Gt, there has been a 14Gt gain in East Antarctica.

Annual sea-level rises are still small but are forecast to increase significantly and the study suggests the most pessimistic forecasts will be proved right.

It comes after a report published earlier this week showed overall sea levels rose 3.2mm a year between 1993 and 2011, 60 per cent above the 2mm estimate in projections by the IPCC. 

The findings, published in the journal Science, were made by an international team of scientists jointly led by Professor Shepherd and Dr Eric Ivins at NASA’s Jet Propulsion Laboratory.

Professor Michiel van den Broeke, of Utrecht University in the Netherlands, warned: “Sea-level rises are at the very upper end of what the IPCC has predicted.”

The causes and mechanisms behind the increased rate of ice loss are not fully understood but it is widely attributed to global warming.

Professor Richard Alley, a climate scientist at Penn State University in the US, who was not involved in the study, said: “This project is a spectacular achievement. The data will support testing of predictive models, and lead to a better understanding of how sea-level change may depend on the human decisions that influence global temperatures.”

Enough ice is contained in the ice sheets to cause sea-level rises, if it all melted, of an estimated 63m – 7m from Greenland and 56m from Antarctica.

Start your day with The Independent, sign up for daily news emails
PROMOTED VIDEO
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Account Manager

£20000 - £35000 per annum: Recruitment Genius: This full service social media ...

Recruitment Genius: Data Analyst - Online Marketing

£24000 - £35000 per annum: Recruitment Genius: We are 'Changemakers in retail'...

Austen Lloyd: Senior Residential Conveyancer

Very Competitive: Austen Lloyd: Senior Conveyancer - South West We are see...

Austen Lloyd: Residential / Commercial Property Solicitor

Excellent Salary: Austen Lloyd: DORSET MARKET TOWN - SENIOR PROPERTY SOLICITOR...

Day In a Page

Isis in Iraq: Yazidi girls killing themselves to escape rape and imprisonment by militants

'Jilan killed herself in the bathroom. She cut her wrists and hanged herself'

Yazidi girls killing themselves to escape rape and imprisonment
Ed Balls interview: 'If I think about the deficit when I'm playing the piano, it all goes wrong'

Ed Balls interview

'If I think about the deficit when I'm playing the piano, it all goes wrong'
He's behind you, dude!

US stars in UK panto

From David Hasselhoff to Jerry Hall
Grace Dent's Christmas Quiz: What are you – a festive curmudgeon or top of the tree?

Grace Dent's Christmas Quiz

What are you – a festive curmudgeon or top of the tree?
Nasa planning to build cloud cities in airships above Venus

Nasa planning to build cloud cities in airships above Venus

Planet’s surface is inhospitable to humans but 30 miles above it is almost perfect
Surrounded by high-rise flats is a little house filled with Lebanon’s history - clocks, rifles, frogmen’s uniforms and colonial helmets

Clocks, rifles, swords, frogmen’s uniforms

Surrounded by high-rise flats is a little house filled with Lebanon’s history
Return to Gaza: Four months on, the wounds left by Israel's bombardment have not yet healed

Four months after the bombardment, Gaza’s wounds are yet to heal

Kim Sengupta is reunited with a man whose plight mirrors the suffering of the Palestinian people
Gastric surgery: Is it really the answer to the UK's obesity epidemic?

Is gastric surgery really the answer to the UK's obesity epidemic?

Critics argue that it’s crazy to operate on healthy people just to stop them eating
Homeless Veterans appeal: Christmas charity auction Part 2 - now LIVE

Homeless Veterans appeal: Christmas charity auction

Bid on original art, or trips of a lifetime to Africa or the 'Corrie' set, and help Homeless Veterans
Pantomime rings the changes to welcome autistic theatre-goers

Autism-friendly theatre

Pantomime leads the pack in quest to welcome all
The week Hollywood got scared and had to grow up a bit

The week Hollywood got scared and had to grow up a bit

Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

Panto dames: before and after

From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
Thirties murder mystery novel is surprise runaway Christmas hit

Thirties murder mystery novel is surprise runaway Christmas hit

Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

Anne-Marie Huby: 'Charities deserve the best'

Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
The botanist who hunts for giant trees at Kew Gardens

The man who hunts giants

A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there