a sudden change of state:
The IPCC predicts that sea levels could rise by as much as 59cm this century(2). Hansen’s paper argues that the slow melting of ice sheets the panel expects doesn’t fit the data. The geological record suggests that ice at the poles does not melt in a gradual and linear fashion, but flips suddenly from one state to another. When temperatures increased to 2-3 degrees above today’s level 3.5 million years ago, sea levels rose not by 59 centimetres but by 25 metres. The ice responded immediately to changes in temperature(3).
(...) Rather than taking thousands of years to melt, as the IPCC predicts, Hansen and his team find it “implausible” that the expected warming before 2100 “would permit a West Antarctic ice sheet of present size to survive even for a century.” As well as drowning most of the world’s centres of population, a sudden disintegration could lead to much higher rises in global temperature, because less ice means less heat reflected back into space. The new paper suggests that the temperature could therefore be twice as sensitive to rising greenhouse gases than the IPCC assumes. “Civilization developed,” Hansen writes, “during a period of unusual climate stability, the Holocene, now almost 12,000 years in duration. That period is about to end.”(4)
(...) I looked up from the paper, almost expecting to see crowds stampeding through the streets. I saw people chatting outside a riverside pub. The other passengers on the train snoozed over their newspapers or played on their mobile phones. Unaware of the causes of our good fortune, blissfully detached from their likely termination, we drift into catastrophe.
(...) Or we are led there. A good source tells me that the British government is well aware that its target for cutting carbon emissions – 60% by 2050 – is too little, too late, but that it will go no further for one reason: it fears losing the support of the Confederation of British Industry. Why this body is allowed to keep holding a gun to our heads has never been explained, but Gordon Brown has just appointed Digby Jones, its former director-general, as a minister in the department responsible for energy policy. I don’t remember voting for him. There could be no clearer signal that the public interest is being drowned by corporate power.
(...) If Hansen is correct, to avert the meltdown that brings the Holocene to an end we require a response on this scale: a sort of political “albedo flip”. The government must immediately commission studies to discover how much of our energy could be produced without fossil fuels, set that as its target then turn the economy round to meet it. But a power shift like this cannot take place without a power shift of another kind: we need a government which fears planetary meltdown more than it fears the CBI.