'Glacial earthquakes' warn of global warming

A A A

Dramatic new evidence has emerged of the speed of climate change in the polar regions which scientists fear is causing huge volumes of ice to melt far faster than predicted.

Scientists have recorded a significant and unexpected increase in the number of "glacial earthquakes" caused by the sudden movement of Manhattan-sized blocks of ice in Greenland.

A second study has found that higher temperatures caused by global warming could melt the Arctic and Antarctic ice sheets much sooner than previously thought, with a corresponding rise in sea levels.

Both studies - along with a series of findings from other scientists over the past year - point to a disturbing change in the polar climate which is causing the disappearance of glaciers, ice sheets and floating sea ice.

The rise in the number of glacial earthquakes over the past four years lends further weight to the idea that Greenland's glaciers and its ice sheet are beginning to move and melt on a scale not seen for perhaps thousands of years.

The annual number of glacial earthquakes recorded in Greenland between 1993 and 2002 was between six and 15. In 2003 seismologists recorded 20 glacial earthquakes. In 2004 they monitored 24 and for the first 10 months of 2005 they recorded 32.

The latest seismic study, published today in the journal Science, found that in a single area of north-western Greenland scientists recorded just one quake between 1993 and 1999. But they monitored more than two dozen quakes between 2000 and 2005.

"People often think of glaciers as inert and slow-moving, but in fact they can also move rather quickly," said Goran Ekstrom, professor of geology and geophysics at Harvard University, who led the study.

"Some of Greenland's glaciers - as large as Manhattan and as tall as the Empire State Building - can move 10 metres in less than a minute, a jolt that is sufficient to generate moderate seismic waves," Professor Ekstrom said.

Average temperatures in the Arctic have risen far faster than in other parts of the world over the past few decades, resulting in the rapid acceleration in polar melting.

As the glacial meltwater seeps down it lubricates the bases of the "outlet" glaciers of the Greenland ice sheet, causing them to slip down surrounding valleys towards the sea, explained Meredith Nettles of Columbia University.

"Our results suggest that these major outlet glaciers can respond to changes in climate conditions much more quickly than we had thought," Dr Nettles said.

"Greenland's glaciers deliver large quantities of freshwater to the oceans, so the implications for climate change are serious. We believe that further warming of the climate is likely to accelerate the behaviour we've documented," she said.

The seismologists also found that the glacial earthquakes of Greenland occurred mainly during the summer months, indicating that the movements were indeed associated with rapidly melting ice - normal "tectonic" earthquakes show no such seasonality. Of the 136 glacial quakes analysed by the scientists, more than a third occurred during July and August.

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Extras
The Tesco Hudl2: An exceptional Android tablet that's powerful, well-built and outstanding value
indybest

Life and Style
food + drinkAuthor DBC Pierre presents his guide to the morning after
Sport
Two christmas trees ,Moonbeam (2L), Moonchester (2R) and Santa Claus outside the Etihad Stadium
footballAll the action from today's games
News
Sarah Silverman (middle) with sister Reform Rabbi Susan Silverman (right) and sister actress Laura Silverman (left) at Jerusalem's Western Wall for feminist Hanuka candle-lighting ceremony
peopleControversial comedian stages pro-equality Hanukkah lighting during a protest at Jerusalem's Wailing Wall
Arts and Entertainment
The Bach Choir has been crowned the inaugural winner of Sky Arts’ show The Great Culture Quiz
arts + ents140-year-old choir declared winner of Sky Arts' 'The Great Culture Quiz'
Life and Style
food + drink
News
i100
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Finance Director

£65000 - £80000 per annum: Recruitment Genius: Finance Director required to jo...

Recruitment Genius: Medico-Legal Assistant

£15000 - £25000 per annum: Recruitment Genius: This is a unique opportunity fo...

Ashdown Group: (PHP / Python) - Global Media firm

£50000 per annum + 26 days holiday,pension: Ashdown Group: A highly successful...

The Jenrick Group: Quality Inspector

£27000 per annum + pension + holidays: The Jenrick Group: A Quality Technician...

Day In a Page

Homeless Veterans appeal: 'You look for someone who's an inspiration and try to be like them'

Homeless Veterans appeal

In 2010, Sgt Gary Jamieson stepped on an IED in Afghanistan and lost his legs and an arm. He reveals what, and who, helped him to make a remarkable recovery
Could cannabis oil reverse the effects of cancer?

Could cannabis oil reverse effects of cancer?

As a film following six patients receiving the controversial treatment is released, Kate Hilpern uncovers a very slippery issue
The Interview movie review: You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here

The Interview movie review

You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here
Serial mania has propelled podcasts into the cultural mainstream

How podcasts became mainstream

People have consumed gripping armchair investigation Serial with a relish typically reserved for box-set binges
Jesus Christ has become an unlikely pin-up for hipster marketing companies

Jesus Christ has become an unlikely pin-up

Kevin Lee Light, aka "Jesus", is the newest client of creative agency Mother while rival agency Anomaly has launched Sexy Jesus, depicting the Messiah in a series of Athena-style poses
Rosetta space mission voted most important scientific breakthrough of 2014

A memorable year for science – if not for mice

The most important scientific breakthroughs of 2014
Christmas cocktails to make you merry: From eggnog to Brown Betty and Rum Bumpo

Christmas cocktails to make you merry

Mulled wine is an essential seasonal treat. But now drinkers are rediscovering other traditional festive tipples. Angela Clutton raises a glass to Christmas cocktails
5 best activity trackers

Fitness technology: 5 best activity trackers

Up the ante in your regimen and change the habits of a lifetime with this wearable tech
Paul Scholes column: It's a little-known fact, but I have played one of the seven dwarves

Paul Scholes column

It's a little-known fact, but I have played one of the seven dwarves
Fifa's travelling circus once again steals limelight from real stars

Fifa's travelling circus once again steals limelight from real stars

Club World Cup kicked into the long grass by the continued farce surrounding Blatter, Garcia, Russia and Qatar
Frank Warren column: 2014 – boxing is back and winning new fans

Frank Warren: Boxing is back and winning new fans

2014 proves it's now one of sport's biggest hitters again
Jeb Bush vs Hillary Clinton: The power dynamics of the two first families

Jeb Bush vs Hillary Clinton

Karen Tumulty explores the power dynamics of the two first families
Stockholm is rivalling Silicon Valley with a hotbed of technology start-ups

Stockholm is rivalling Silicon Valley

The Swedish capital is home to two of the most popular video games in the world, as well as thousands of technology start-ups worth hundreds of millions of pounds – and it's all happened since 2009
Did Japanese workers really get their symbols mixed up and display Santa on a crucifix?

Crucified Santa: Urban myth refuses to die

The story goes that Japanese store workers created a life-size effigy of a smiling "Father Kurisumasu" attached to a facsimile of Our Lord's final instrument of torture
Jennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress

The Boy in the Dress: On set with the stars

Walliams' story about a boy who goes to school in a dress will be shown this Christmas