Dear G8 leaders,
It contains a fascinating gap, which as ever comes in those failsafe square brackets so beloved of civil servants and diplomats. The first bullet-point in paragraph 6 reads:
- There is now compelling evidence [statement on scientific evidence of the need for action].
The precise wording of whatever statement is to go inside those bureaucratic brackets is, clearly, sensitive territory. Downing Street diplomats and their scientific advisers cant quite agree on what to put in. They dont want to scare the Americans, after all.
So here is what you should be considering.
The world is approaching an abyss. We dont know exactly where the edge is, but there is a strong case that an average global temperature rise of 2 degrees Centigrade above pre-industrial levels will take us there. That is just 1.3 degrees warmer than today. On current trends we will be there before 2050, and it may be too late to slam on the brakes any time after about 2020.
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Somewhere around that two-degree figure, warming may start to trigger a series of irreversible shudders through the Earth system climatic equivalents of a tsunami.
They may include the runaway melting of the Greenland and west Antarctic ice-sheets, which would add thirteen metres to sea levels worldwide; a shutdown of the warm Gulf Stream, giving western Europe near-Siberian temperatures. It could even include the release of huge stocks of methane currently frozen in the Siberian tundra and beneath the Arctic seabed stocks sufficient to raise global temperatures by a further ten degrees or more.
Science fiction? Not at all. These terrifying prospects come from a meeting of the worlds top climate scientists, organised by the British government at the Met Office in Exeter, western England, in February 2005 (see Stabilisation 2005).
In their dispassionate way, the scientists present called these wild and sudden events type II climate change, as distinct from the more gradual type I stuff you are probably more familiar with. John Schellnhuber, director of the Tyndall Centre for Climate Change in Cambridge, put it more bluntly: We now know that if we go beyond two degrees we will raise hell.
It was the fear of type II climate change that encouraged European Union leaders in March to adopt the two-degree target. We may hope that, by the time Tony Blairs drafters have filled in their square brackets, it puts in an appearance in the G8 statement you will be asked to sign. If not, please put it in.
You may remember that at the Earth Summit in 1992 your predecessors, including the father of George W Bush, signed a climate-change convention agreeing to prevent dangerous climate change. At the time, nobody knew quite what that might mean. So the targets for cutting greenhouse-gas emissions in the Kyoto Protocol five years later were a holding operation.
But now we have a scientifically coherent benchmark for how dangerous climate change might be. So lets use it.
How do we go forward? For the answer, listen to David Warrilow, head of the global atmosphere division at Britains department for environment, food and rural affairs (Defra), at a mid-May meeting in Bonn of government experts on what should follow when the Kyoto targets expire in 2012.
To prevent a two-degree warming, Warrilow said, we probably have to restrict the amount of the main warming gas, carbon dioxide. This would mean that from 2000-2100 we would need to put fewer than 600 billion tonnes into the atmosphere. But on current trends, he said, we will have emitted 400 billion tonnes by 2030.
Do the maths: big cuts are needed. Quickly.
Warrilow followed up with an overhead of the Titanic. The captain of that ship received five warnings of icebergs ahead, but only slammed on the brakes when he actually saw the ice in front of him. Too late. You might conclude that we too are sailing full steam ahead, oblivious to the warnings of icebergs ahead.
We are inclined to believe such disasters as those outlined at the Exeter meeting couldnt happen. But they have in the past. Within the past 20,000 years, nature has shut down the Gulf Stream, lowered temperatures by six to eight degrees within a couple of decades, and raised sea levels by twenty metres in 400 years or five centimetres a year. Nature could do so again, and climatologists say our reckless management of the climate system makes that a racing certainty.
You might think that Earths ship is unsinkable. But it may be no accident that the entire period of human civilisation has happened during a period of climatic tranquillity on the planet that now appears to be quite unusual. We mess with it at our considerable peril.
Dont despair. There is a reassuring range of technologies available that could cut our emissions quickly and relatively cheaply. Even the high end of the estimated bill suggests that only a couple years delay in raising GDP spread over many decades would be involved. A small price to pay, you might think.
You aspire to be the leaders of the current flowering of human civilisation. Your countries are responsible for almost half current global warming. You cant solve all the problems in Gleneagles. But do check that bullet-point, and consider your options.
This article appears as part of openDemocracys online debate on the politics of climate change. The debate was developed in partnership with the British Council as part of their ZeroCarbonCity initiative a two year global campaign to raise awareness and stimulate debate around the challenges of climate change.
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