The Earth is going thin on top. A new study has revealed that the Arctic Ocean’s permanent blanket of ice around the North Pole has thinned by more than 40% since 2004. Scientists said the rapid loss was “remarkable” and said it could force experts to reassess how quickly the Arctic ice in the summer may disappear completely. They have called for more research to pin down the causes of the change, which they say is probably down to increased melting and shifts in the way the ice moves around.

The study, based on satellite measurements, is among the first to estimate the thickness of the Arctic ice, rather than just its surface area.

Ron Kwok, senior research scientist at Nasa’s Jet Propulsion Laboratory in California, said: “Even in years when the overall extent of sea ice remains stable or grows slightly, the thickness and volume of the ice cover is continuing to decline, making the ice more vulnerable to continued shrinkage.”

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The study looked at measurements taken of the Arctic region by the ICESat satellite, launched in 2003.

Overall, the experts found that the ice, typically up to about 3m thick, thinned by 67cm over the last four winters.

Converting to ice volume, the scientists worked out the amount of so-called multiyear ice, which persists through Arctic summers, had decreased in the winter by up to 6,300 cubic kilometres since 2005 – a decline of more than 40%. The research is published in the Journal of Geophysical Research: Oceans.

Kwok said: “Ice volume allows us to calculate annual ice production and gives us an inventory of the fresh water and total ice mass stored in Arctic sea ice. Our data will help scientists better understand how fast the volume of Arctic ice is decreasing and how soon we might see a nearly ice-free Arctic in summer.”

The Arctic ice cap fluctuates with the seasons, growing in the freezing winter and shrinking over the summer. An important finding of the study is that the majority of Arctic ice no longer survives the summer. In 2003, this multiyear ice made up 62% of the region’s total ice volume. By 2008, this was down to 32%. The remaining 68% was “first-year” seasonal ice, which was open water during the summer, so is thinner and more likely to melt away.

Earlier this year, scientists warned that sea ice volume reached a record low in 2008 due to an unusually high proportion of the thinner first year ice.

The Obama administration endorsed a revival of America’s nuclear industry yesterday in an effort to build forward momentum for climate change legislation before the Senate.

 

The seal of approval for nuclear power – a cause embraced by Republican senators – came on day one of a full-on lobbying effort by the White House for one of Obama’s signature issues.

 

Obama sent four of his top lieutenants to the Senate – his secretaries of energy, interior, agriculture and the head of the Environmental Protection Agency (EPA) – to try to drum up support for a global warming bill.

 

The PR effort saw direct appeals to the farming and nuclear lobbies – some of the fiercest critics of Obama’s clean energy agenda – with Steven Chu, the Nobel-winning energy secretary, calling for new nuclear plants to re-establish America’s technological dominance in the world.

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“I think nuclear power is going to be a very important factor in getting us to a low carbon future,” Chu told the Senate’s environment and public works committee. “Quite frankly, we want to recapture the lead on industrial nuclear power. We have lost that lead as we have lost the lead in many energy technologies and we want to get it back.”

 

The endorsement of a nuclear revival – a generation after the last reactor was commissioned – suggests the Obama administration is open to further compromises as it seeks to find a path through the Senate. The House of Representatives narrowly passed a climate change bill late last month.

 

Republicans in the Senate, who are almost universally opposed to action aimed at reducing greenhouse gas emissions, as well as Democrats from rust belt states, have been clamouring for a “nuclear renaissance” in America, which would see the construction of 100 new nuclear power plants by 2030.

 

The administration officials also tried to make inroads among the powerful farmers’ lobby, saying they hoped the effort could help ensure passage of the bill through the Senate.

 

 

Yesterday’s hearing marks the opening round of a second major push by the White House for Obama’s climate and energy agenda.

 

Obama is in Europe where he hopes to persuade the G8 to commit to limiting global warming to 2C, and to persuade Russia to make its lumbering industries more efficient.

 

But the White House acknowledges it must also demonstrate American willingness by ensuring passage of a climate bill through both houses of Congress by December, when international climate change negotiations end in Copenhagen. It is widely believed that the international community will not sign up to action on climate change without evidence of US commitment.

 

The Democratic leadership in the Senate hopes to use the house bill as a template. It has pencilled in a schedule that would see the bill clear the committee process by mid-September and move to vote by late autumn.

 

But the way ahead is daunting. Despite the Democrats’ 77-seat advantage in the house, the bill gained just 219 votes – one more than a bare majority – and the reform package had swollen to more than 1,427 pages. Much of that bloat was in the political sops to ensure the bill’s support: concessions to farmers that ultimately damage the bill, protectionist measures to help heavily polluting industries – and even a hurricane centre in Florida.

 

 

 

The administration’s case is also damaged by rising criticism of the bill, from environmentalists who say it does not go far enough as well as those opposed to any action.

 

Lisa Jackson, head of the EPA, stopped short of endorsing the package yesterday, saying: “It sends the right signal and you all in the Senate have work to do.”

 

But she said the Senate had little choice, and that inaction on climate change could lead to America’s global economic decline.

 

“Clean energy is to this decade and the next what the space race was to the 1950s and 60s and America is behind,” Jackson told the Senate. “Governments in Asia and Europe are ahead of the United States in making aggressive investments in clean energy technology.”