Wednesday, October 25, 2006


FIONA HARVEY, FINANCIAL TIMES - A growing body of scientific opinion
suggests the world may be about to experience not a gradual rise in
temperatures over several decades but a wild careering into climate
chaos. That is because some of the changes triggered by warming
temperatures create a "feedback" effect of their own. These feedbacks
can cause the warming trend to accelerate further or bring serious
disruption to regions of the world
In this view, the rising proportion of carbon dioxide in the atmosphere,
by creating feedbacks, is pushing the earth's climate through a series
of thresholds or tipping points that threaten to bring cataclysmic
consequences. Those could include a much more rapid melting of the
Arctic ice and the Greenland ice sheet than previously predicted, the
accelerated melting of permafrost, the cessation of the Indian monsoon,
a rapid dying back of forest in the Amazon and a halting of the sea
currents that help bring warm weather to Europe. . .

Peter Smith, special professor in sustainable energy at Nottingham
University, told the British Association science festival last week: "We
could reach the tipping point within 15 to 20 years from now, which
would give us just 10 years in which to determine the destiny of our
planet." Jay Gulledge, senior research fellow at the Pew Centre on
Global Climate Change, says climatologists "have dramatically
under-estimated how responsive the climate is to warming".

The world's current attempts to cut emissions, such as the Kyoto
protocol and the Asia-Pacific Partnership on Clean Development and
Climate, a collaboration between developed and developing countries,
presume a slowdown over decades of the rate of increase in the world's
output of greenhouse gases. But Myles Allen of Oxford University, one of
the leaders of a project that predicted up to 11 degrees of warming,
says: "The danger zone is not something that we are going to reach in
the middle of this century. We are in it now."

"It is not too late to save the Arctic, but it requires that we begin to
slow CO2 emissions this decade," says James Hansen, director of NASA's
Goddard Institute for Space Studies.

Talk of feedback effects and tipping points is still controversial among
scientists, however. Tim Lenton, reader in earth systems analysis at the
University of East Anglia, is conducting a review of the science of
feedbacks and tipping points. He says: "There has been quite a lot of
hyperbole around this.". . .
One of the main topics of informal discussion at the meeting will be the
fourth assessment report, due out next year, of the Intergovernmental
Panel on Climate Change, the scientific study that underpins Kyoto. The
draft version of the report suggests that the notion of tipping points
and positive feedbacks will play a minor role. It is likely to predict
an average global warming of 3 degrees Celsius by 2100.

Though some warn against overstating the feedback effect and the near
approach of tipping points, most climate scientists accept the
possibility that the climate will change abruptly rather than warm
gradually. But this is not adequately taken into account at the highest
levels of politics. Mr Lenton, describing this as a serious omission,
says the climate is subject to "highly non-linear change".

He elaborates: "The curve is not smooth, in other words. But the typical
economic approach has smooth curves. This is a conceptual shift, from a
smooth curve to stepped rises, that if policy-makers could get hold of
could transform the way we think about this."

principles of poker, it turns out, are useful lessons for thinking about
the environment. . . [Here are] two bad bets:

1. To assume that there is no risk until you prove there is a risk.

2. To assume that there is no risk in doing nothing. . . If you toss a
coin there is a fifty percent chance it will come up tails; if you
repeatedly toss a coin, however, there is almost a hundred percent
chance that it will eventually come up tails. Now if the down side of
your game is not merely a coin that lands tails up, but the loss of your
house -- or a nuclear plant radiation leak or a massive oil spill --
then the probability of something happening ever becomes far more
important than the probability of it happening on a particular occasion.

Finally we come to the ultimate game -- a long future of uncertainty and
highly disputable odds, in which the ante is the earth and human life
itself. . . Now we have unknown odds but enormous stakes. So what does
poker have to tell us? It says you have to know when to hold them and
know when to fold them. And as a rule of thumb, whatever the odds, you
don't want to bet either your house or your planet on a game of chance.
. .

Take the Gulf Stream, for example. We simply don't know what changes in
climate or water currents and temperatures might cause the Gulf Stream
to shift directions. As Stanford population studies professor Paul
Ehrlich has pointed out, "what scares [experts] is the knowledge that
weather is driven by small differences between large numbers." Let's
imagine, for example that some climatic change causes the Gulf Stream to
cross an invisible threshold and, as a result, it moves away from
Europe. A very small but very wrong alteration could easily create the
world's newest ski resorts in the hills of Wales, give Ireland the
climate of Nova Scotia and make London ( at least until everyone moves
out) the largest Arctic city in the world. Bear in mind that London sits
near the latitude of Winnipeg, Nice and the Riviera are due east of
Boston, and Paris lies north of Quebec. . .



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