The good news: there has been a dramatic increase in Arctic sea ice. The bad news: it's still half the level is was in the 1980s

Even worse, the rebound is probably only a temporary respite

Science Editor

A A A

The volume of the sea ice floating in the Arctic Ocean increased by about 50 per cent in October compared to the same period of 2012, which was one of the lowest on record, scientists said.

Europe's CryoSat satellite, which is designed to monitor sea-ice thickness, measured about 9,000 cubic kilometres of sea ice in October 2013, a notable increase compare to the 6,000 cu km seen in October last year.

Scientists said that the rebound probably marks a temporary respite for the polar region, which has seen dramatic and long-term changes in recent decades due to regional warming that has melted Arctic ice on both land and sea.

The extent of the surface area covered by sea ice - measured by a different satellite - also saw an increase on the previous year, however it was still the sixth lowest since satellite records began in 1979. The seven lowest recorded sea-ice extents have all occurred in the last seven years.

Sea ice naturally increases from about mid-September to March and then recedes again during the warmer summer months. However, measurements from satellites and nuclear-powered submarines all show a significant long-term average decline in both sea ice volume and surface area extent over the past four decades.

Although last October saw a significant return of the sea ice compared to the previous October, it was still less than half the estimated volume of the same time period in the early 1980s, said Professor Andrew Shepherd from University College London.

"The 9,000 cubic kilometres we measured in October is still very much smaller than the 20,000 cubic kilometres we estimate for the same time in the early 1980s. So today's minimum still ranks among the lowest for the past 30 years," Professor Shepherd said.

"The October figure is still a significant result and it's not to be underestimated, but it's not an unexpected result. We do see year-to-year variations in the sea ice due to changes in weather patterns," he said.

The European Space Agency's Cryosat satellite, which has been operating for four years, found that 90 per cent of the rebound was due to sea ice that had survived the summer melt season, the so-called "multiyear" ice. Just 10 per cent was first-year ice that had newly formed.

It found that the multiyear ice, which is generally thicker than single-year ice, is now on average about 20 per cent or around 30 centimetres thicker than the previous year, said Rachel Tilling the UK's Centre for Polar Observation and Modelling, who led the study.

"One of the things we'd noticed in our data was that the volume of ice year-to-year was not varying anything like as much as the ice extent - at least in 2010, 2011 and 2012. We didn't expect the greater ice extent left at the end of this summer's melt to be reflected in the volume. But it has been, and the reason is related to the amount of multiyear ice in the Arctic," Dr Tilling said.

An Arctic "report card" for 2013, presented to the American Geophysical Union last week, found that the long-term trends in the polar region continued to show that it is warming rapidly and as a result has experienced dramatic changes, such as decreased snow cover, melting permafrost and diminishing ice both on land and sea.

"The Arctic Report Card presents strong evidence of widespread, sustained changes that are driving the Arctic environmental system into a new state and we can expect to see continued widespread and continued changes in the Arctic," said Martin Jeffries, of the University of Alaska, Fairbanks.

David Kennedy, deputy undersecretary for operations as the US National Oceanic and Atmospheric Administration, said: "The Arctic caught a bit of break in 2013 from the recent string of record-breaking warmth and ice melts of the last decade. But the relatively cool year in some parts of the Arctic does little to offset the long-term trend of the last 30 years: the Arctic is warming rapidly."

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Austen Lloyd: Private Client Solicitor - Oxford

Excellent Salary : Austen Lloyd: OXFORD - REGIONAL FIRM - An excellent opportu...

Austen Lloyd: Clinical Negligence Associate / Partner - Bristol

Super Package: Austen Lloyd: BRISTOL - SENIOR CLINICAL NEGLIGENCE - An outstan...

Recruitment Genius: Sales Consultant - Solar Energy - OTE £50,000

£15000 - £50000 per annum: Recruitment Genius: Fantastic opportunities are ava...

Recruitment Genius: Compute Engineer

Negotiable: Recruitment Genius: A Compute Engineer is required to join a globa...

Day In a Page

Iraq invasion 2003: The bloody warnings six wise men gave to Tony Blair as he prepared to launch poorly planned campaign

What the six wise men told Tony Blair

Months before the invasion of Iraq in 2003, experts sought to warn the PM about his plans. Here, four of them recall that day
25 years of The Independent on Sunday: The stories, the writers and the changes over the last quarter of a century

25 years of The Independent on Sunday

The stories, the writers and the changes over the last quarter of a century
Homeless Veterans appeal: 'Really caring is a dangerous emotion in this kind of work'

Homeless Veterans appeal

As head of The Soldiers' Charity, Martin Rutledge has to temper compassion with realism. He tells Chris Green how his Army career prepared him
Wu-Tang Clan and The Sexual Objects offer fans a chance to own the only copies of their latest albums

Smash hit go under the hammer

It's nice to pick up a new record once in a while, but the purchasers of two latest releases can go a step further - by buying the only copy
Geeks who rocked the world: Documentary looks back at origins of the computer-games industry

The geeks who rocked the world

A new documentary looks back at origins of the computer-games industry
Belle & Sebastian interview: Stuart Murdoch reveals how the band is taking a new direction

Belle & Sebastian is taking a new direction

Twenty years ago, Belle & Sebastian was a fey indie band from Glasgow. It still is – except today, as prime mover Stuart Murdoch admits, it has a global cult following, from Hollywood to South Korea
America: Land of the free, home of the political dynasty

America: Land of the free, home of the political dynasty

These days in the US things are pretty much stuck where they are, both in politics and society at large, says Rupert Cornwell
A graphic history of US civil rights – in comic book form

A graphic history of US civil rights – in comic book form

A veteran of the Fifties campaigns is inspiring a new generation of activists
Winston Churchill: the enigma of a British hero

Winston Churchill: the enigma of a British hero

A C Benson called him 'a horrid little fellow', George Orwell would have shot him, but what a giant he seems now, says DJ Taylor
Growing mussels: Precious freshwater shellfish are thriving in a unique green project

Growing mussels

Precious freshwater shellfish are thriving in a unique green project
Diana Krall: The jazz singer on being friends with Elton John, outer space and skiing in Dubai

Diana Krall interview

The jazz singer on being friends with Elton John, outer space and skiing in Dubai
Pinstriped for action: A glimpse of what the very rich man will be wearing this winter

Pinstriped for action

A glimpse of what the very rich man will be wearing this winter
Russell T Davies & Ben Cook: 'Our friendship flourished online. You can share some very revelatory moments at four in the morning…'

Russell T Davies & Ben Cook: How we met

'Our friendship flourished online. You can share some very revelatory moments at four in the morning…'
Bill Granger recipes: Our chef serves up his favourite Japanese dishes

Bill Granger's Japanese recipes

Stock up on mirin, soy and miso and you have the makings of everyday Japanese cuisine
Michael Calvin: How we need more Eric Cantonas to knock some sense into us

Michael Calvin's Last Word

How we need more Eric Cantonas to knock some sense into us