Arctic Ocean 'will be ice-free within 20 years'

Global warming will leave the Arctic Ocean ice-free during the summer within 20 years, raising sea levels and harming wildlife, a leading British polar scientist said today.

The changes will mean the top of the Earth will appear blue rather than white when photographed from space and ships will have a new sea route north of Russia.

The Catlin Arctic Survey, completed earlier this year by a team led by veteran polar explorer Pen Hadow, is the latest research into the condition of Arctic ice.

Global warming: Veteran polar explorer Pen Hadow and Ann Daniels prepare to swim through thin Arctic ice during their research completed earlier this year

Open sea: Ann Daniels during the Catlin Arctic Survey, which found that the Arctic Ocean will be almost entirely free from ice within a decade

Drilling and observation figures obtained during a 450km route across the northern part of the Beaufort Sea suggest the area is almost entirely made up of young, 'first-year' ice, whereas the region traditionally consists of older, thicker 'multi-year' ice.

Peter Wadhams, Professor of Ocean Physics at Cambridge University, has spearheaded the team analysing the results.

He said much of the melting will take place within a decade, although the winter ice will stay for hundreds of years.

'The summer ice cover in the Arctic will completely vanish in 20 to 30 years time. There won't be any sea ice there at all,' he said.

'In much less time than that, the ice in summer will be shrinking back to this last bastion north of Greenland and Ellesmere Island, so within a decade we will see a largely ice-free Arctic Ocean in summer.

'It won't be very long before we have to start thinking of the Arctic as an open sea. Man has taken the lid off the northern end of his planet and we can't put that lid back on again.

crucial: Most of the decrease in sea ice will happen before 2020, leaving the Arctic Ocean clear for marine transport

Calling for a 'solid deal' in Copenhagen, Dr Sommerkorn added: 'Such a loss of Arctic sea ice cover has recently been assessed to set in motion powerful climate feedbacks, which will have an impact far beyond the Arctic itself - self-perpetuating cycles, amplifying and accelerating the consequences of global warming.

'This could lead to flooding affecting one quarter of the world's population, substantial increases in greenhouse gas emission from massive carbon pools and extreme global weather changes.

'Remove the sea ice and we are left with a much warmer and very different world.'

Hadow, the first person to trek solo and unsupported from Canada to the Geographic North Pole, said his 73-day expedition had added weight to a growing consensus that Arctic summer ice sheets would be all but gone in 10 years.

Explorer Pen Hadow led the 73-day expedition across the Arctic

The 37-year-old explorer said: 'Quite lot of the public's understanding has been focused on 100per cent loss - mathematical closure, as I would call it.

'It's not really relevant whether you have got the last 10per cent, 2per cent, 1per cent (of Arctic ice) - the point is in terms of how it is going to impact on related climate, oceanic and atmospheric systems, and therefore our weather and so on: our lives.

'If you've got an 80per cent or 85per cent loss, job done. So let's focus on when most of it is gone - that's the timeframe that I feel is the one that's relevant to policy and to our lives.'

The average thickness of ice floes measured during the survey was 1.8 metres - a depth considered too thin to last a summer ice melt.

Hadow and fellow explorers Ann Daniels and Martin Hartley battled a wind chill of minus 70, delayed resupply flights and starvation rations during the expedition from March 1 to May 7 this year.

The expedition was blighted by numerous technical breakdowns, including that of a radar system intended to measure the ice as they trekked. Its failure forced the team to hand-drill the ice instead, slowing progress.

Hadow explained how polar explorers were having to change their means of transport from sledges pulled by dogs to canoes.

He said: Dogs can swim but they can't tow a sledge through water which is what's needed now.

'Now we have to wear immersion suits and swim and we need sledges that can float.

'I can foresee needing sledges that are more like canoes that you also pull over the ice.'