“This is one of the most serious problems the world has ever faced.” – Peter Wadhams, professor of ocean physics at Cambridge University

The U.K. Sunday Times Online reports further evidence that global warming has reached the emergency stage:

“The Arctic icecap is now shrinking at record rates in the winter as well as summer, adding to evidence of disastrous melting near the North Pole.”

The article reports that last winter the thickness of sea ice decreased in places by as much as 19%. The Guardian also has a story on the study, which was funded in part by the Natural Environment Research Council and the European Union.

In 2008, the summer shrinkage  for the first time resulted in the opening of both the Northwest and the Northeast passages – even though the weather was not unusually warm. The summer melting now appears to be continuing even during the winter months.

The Times article quotes Dr. Katharine Giles, who led the study and is based at the Centre for Polar Observation and Modelling at University College London (UCL):

“After the summer 2007 record melting, the thickness of the winter ice also nose-dived. What is concerning is that sea ice is not just receding but it is also thinning.”

The cause of the thinning is potentially even more alarming. The team found that the winter air temperatures in 2007 were cold enough that they could not have been the cause, suggesting that some other, longer-term change, such as a rise in water temperature or a change in ocean circulation that has brought warmer water under the ice, was at work. This could mean that the Arctic is likely to melt much faster than had been thought and that the summer icecap could vanish within a decade.

A feedback loop is key to the Arctic melting. Ice is white, so most of the solar energy hitting it is reflected back into space. When it melts, the darker open ocean absorbs more solar energy and gets warmer, melting more ice and making it harder for ice to form again in winter. The process feeds on itself until there is no more ice to melt.

David Spratt, co-author of Climate Code Red: the case for emergency action, in a forum at the Environmental Activists’ Conference ‘08: Climate Emergency — No More Business as Usual, in Adelaide, Australia, said that most of the public policy debate on climate is delusional, that is, a fixed, false belief resistant to reason or confrontation with actual fact. There is no realization of how serious our predicament is.

The Arctic is key to the world’s climate, and Arctic changes have the potential to seriously destabilize the global climate system. Events in the polar north should be turning the world of climate policy upside down. Melting is happening “a hundred years ahead of schedule”. Yet the international policy debate is still being carried on as if nothing is happening. And of course the national and local policy debate has yet to begun in earnest.

Spratt expands on what the feedback loops imply:

“The danger is that an ice-free state in the Arctic summer will kick the climate system into run-on warming and create an aberrant new climate state many, many degrees hotter. The Arctic sea-ice is the first domino and it is falling fast. Other dominos will inevitably fall unless we stop emitting greenhouse gases and cool the planet to get the Arctic sea-ice back.

“Those dominoes include the Greenland ice sheet. . . ‘We are close to being committed to a collapse of the Greenland ice sheet . . . If Greenland totally melts, global sea levels will rise by 7 metres. The question, given the present trajectory of the climate system is not if, but how fast?  The general view is 1–2 metres this century, but . . . 4 metres cannot be ruled out; in past climate history 14,000 years ago, sea levels rose as fast as 5 metres per century.

“The rapid regional warming consequent to the sea-ice loss also has grave repercussions for the permafrost. Permafrost areas hold 500 billion tonnes of carbon, which can fast turn into greenhouse gases . . . the question is no longer whether the permafrost will start to melt, but if and when the time-bomb will go off. . . It could happen as early as mid-century.”

As Spratt says, the time to act is now:

Unless we adopt the strongest measures — emergency action  — it will be too late. It is no longer a matter of how much more we can heat the planet, but how quickly can we cool it.