The big thaw: Greenland ice cover is melting away

 

A A A

The vast ice sheet of Greenland, which holds enough water to raise global sea levels by 7.2 metres, underwent a remarkable transformation for a few days this month when scientists observed an unprecedented melting of its frozen surface.

Click HERE to view graphic

For the first time since satellites began recording changes to Greenland from space more than 30 years ago, scientists observed surface melting across almost the entire ice sheet – the second largest body of ice after Antarctica.

At this time of the year, about half of the surface of the ice sheet usually experiences some kind of surface melting as summer day-time temperatures rise above freezing point.

However, scientists at the US National Aeronautics and Space Administration (Nasa) were amazed to discover that on 11 and 12 July surface melting had extended across 97 per cent of the ice sheet – the most widespread melting they have witnessed.

The observation comes just weeks after an iceberg twice the size of Manhattan broke away from the Petermann glacier in northern Greenland and other scientists recorded a rapid loss of floating sea ice further north in the Arctic basin.

The phenomenon in Greenland was so unusual and unexpected that researchers at Nasa’s Jet Propulsion Laboratory (JPL) in Pasadena, California initially could not believe what they were seeing and so quickly sought verification from colleagues elsewhere.

“This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?” said Son Nghiem, whose job at JPL was to analyse radar data from the Indian Space Research Organisation’s Oceansat-2 satellite.

Dorothy Hall at Nasa’s Goddard Space Flight Centre in Greenbelt, Maryland, soon supplied the verification in the form of temperature data from two other Nasa satellites. She confirmed unusually high temperatures over the entire ice sheet, which at 1.7m square kilometres is three times the size of Texas, or more than 16 times the size of England.

Thomas Mote, a climatologist at the University of Georgia, then came up with a meteorological explanation for the highly unusual observation. A ridge of warm air, called a heat dome, has formed over Greenland.

Dr Mote said that it was in fact the latest of a series of ridges that had dominated Greenland’s weather since the end of May. “Each successive ridge has been stronger than the previous one,” he said.

What was so unusual was the extent of the melting. It was even taking place near the highest point in Greenland, around Summit Station which is 3.2 km (2 miles) above sea level, which hardly ever melts.

In fact, according to ice cores taken from the region, the Summit of the Greenland ice sheet has not experienced melting of this kind since 1889, according to Lora Koenig, a Nasa glaciologist at Goddard.

“Ice cores from Summit show that melting events of this type occur once every 150 years on average. With the last one happening in 1889, this event is right on time,” Dr Koenig said.

So the unprecedented melting monitored by satellites might just be a natural event, or it could indicate more serious climate change. “If we continue to observe melting events like this in the coming years, it will be worrisome,” Dr Koenig said.

The Greenland ice sheet is 2,400 km long, 1,100 km wide, and up to 3km thick at its highest point. The current ice sheet is believed to be 110,000 years old, but there may have been ice sheets on Greenland for 18 million years or more.

Have you tried new the Independent Digital Edition apps?
News
i100
Arts and Entertainment
Billie Piper as Brona in Penny Dreadful
tvReview: It’s business as usual in Victorian London. Let’s hope that changes as we get further into the new series spoiler alert
Life and Style
A nurse tends to a recovering patient on a general ward at The Queen Elizabeth Hospital in Birmingham
health
News
science
Arts and Entertainment
No Offence
tvReview: No Offence has characters who are larger than life and yet somehow completely true to life at the same time spoiler alert
News
Chuck Norris pictured in 1996
people
Arts and Entertainment
Sarah Lucas, I SCREAM DADDIO, Installation View, British Pavilion 2015
artWhy Sarah Lucas is the perfect choice to represent British art at the Venice Biennale
News
A voter placing a ballot paper in the box at a polling station
i100
News
people
Arts and Entertainment
The Queen (Kristin Scott Thomas) in The Audience
theatreReview: Stephen Daldry's direction is crisp in perfectly-timed revival
Sport
football
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

SThree: Trainee Recruitment Consultant - Dublin

£13676.46 - £16411.61 per annum + OTE: SThree: SThree Trainee Recruitment Cons...

Ashdown Group: Marketing or Business Graduate Opportunity - Norwich - £22,000

£18000 - £22000 per annum + training: Ashdown Group: Business and Marketing Gr...

SThree: Trainee Recruitment Consultant

£20000 - £25000 per annum + Commission: SThree: Are you great at building rela...

Ashdown Group: Database Analyst - Birmingham - £22,000 plus benefits

£20000 - £22000 per annum + excellent benefits: Ashdown Group: Application Sup...

Day In a Page

General Election 2015: Ed Miliband's unlikely journey from hapless geek to heart-throb

Miliband's unlikely journey from hapless geek to heart-throb

He was meant to be Labour's biggest handicap - but has become almost an asset
General Election 2015: A guide to the smaller parties, from the the National Health Action Party to the Church of the Militant Elvis Party

On the margins

From Militant Elvis to Women's Equality: a guide to the underdogs standing in the election
Amr Darrag: Ex-Muslim Brotherhood minister in exile still believes Egypt's military regime can be replaced with 'moderate' Islamic rule

'This is the battle of young Egypt for the future of our country'

Ex-Muslim Brotherhood minister Amr Darrag still believes the opposition can rid Egypt of its military regime and replace it with 'moderate' Islamic rule, he tells Robert Fisk
Why patients must rely less on doctors: Improving our own health is the 'blockbuster drug of the century'

Why patients must rely less on doctors

Improving our own health is the 'blockbuster drug of the century'
Sarah Lucas is the perfect artist to represent Britain at the Venice Biennale

Flesh in Venice

Sarah Lucas has filled the British pavilion at the Venice Biennale with slinky cats and casts of her female friends' private parts. It makes you proud to be a woman, says Karen Wright
11 best anti-ageing day creams

11 best anti-ageing day creams

Slow down the ageing process with one of these high-performance, hardworking anti-agers
Juventus 2 Real Madrid 1: Five things we learnt, including Iker Casillas is past it and Carlos Tevez remains effective

Juventus vs Real Madrid

Five things we learnt from the Italian's Champions League first leg win over the Spanish giants
Ashes 2015: Test series looks a lost cause for England... whoever takes over as ECB director of cricket

Ashes series looks a lost cause for England...

Whoever takes over as ECB director of cricket, says Stephen Brenkley
Fishing for votes with Nigel Farage: The Ukip leader shows how he can work an audience as he casts his line to the disaffected of Grimsby

Fishing is on Nigel Farage's mind

Ukip leader casts a line to the disaffected
Who is bombing whom in the Middle East? It's amazing they don't all hit each other

Who is bombing whom in the Middle East?

Robert Fisk untangles the countries and factions
China's influence on fashion: At the top of the game both creatively and commercially

China's influence on fashion

At the top of the game both creatively and commercially
Lord O’Donnell: Former cabinet secretary on the election and life away from the levers of power

The man known as GOD has a reputation for getting the job done

Lord O'Donnell's three principles of rule
Rainbow shades: It's all bright on the night

Rainbow shades

It's all bright on the night
'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power