Policies that could cost millions of lives

George MONBIOT

RICH NATIONS: Seeking to cut climate change have this in common: they lie. You won't find this statement in the draft of the new report by the Intergovernmental Panel on Climate Change. But as soon as you understand the numbers, the words form before your eyes.

The governments making genuine efforts to tackle global warming are using figures they know to be false.

The British Government, the European Union, and the United Nations all claim to be trying to prevent "dangerous" climate change.

Any level of climate change is dangerous for someone, but there is a broad consensus about what this word means: two degrees of warming above pre-industrial levels.

It is dangerous because of its direct impacts on people and places (it could, for example, trigger the irreversible melting of the Greenland ice sheet and the collapse of the Amazon rainforest) and because it is likely to stimulate further warming, as it encourages the world's natural systems to start releasing greenhouse gases.

The aim of preventing more than 2 degrees Celsius of warming has been adopted overtly by the U.N. and the EU, and implicitly by the British, German, and Swedish governments.

All of them say they are hoping to confine the concentrations of greenhouse gases in the atmosphere to a level that would prevent such a rise.

And all of them know that they have set the wrong targets, based on outdated science. Fearful of the political implications, they have failed to adjust to the levels the new research demands.

Complex statistics This isn't easy to follow, but please bear with me, as you cannot understand the world's most important issue without grappling with some numbers. The average global temperature is affected by the concentration of greenhouse gases in the atmosphere.

This concentration is usually expressed as "carbon dioxide equivalent." It is not an exact science, you cannot say that a certain concentration of gases will lead to a precise increase in temperature, but scientists discuss the relationship in terms of probability.

A paper published last year by climatologist Malte Meinshausen suggests that if greenhouse gases reach a concentration of 550 parts per million carbon dioxide equivalent, there is a 63-99 per cent chance (with an average value of 82 per cent) that global warming will exceed two degrees.

At 475 parts per million (ppm) the average likelihood is 64 per cent. Only if concentrations are stabilised at 400 parts or below is there a low chance (an average of 28 per cent) that temperatures will rise by more than two degrees.

The IPCC's draft report contains similar figures. A concentration of 510 ppm gives us a 33 per cent chance of preventing more than two degrees of warming. A concentration of 590 ppm gives us a 10 per cent chance.

You begin to understand the scale of the challenge when you discover that the current level of greenhouse gases in the atmosphere (using the IPCC's formula) is 459 ppm. We have already exceeded the safe level.

To give ourselves a high chance of preventing dangerous climate change, we will need a programme so drastic that greenhouse gases in the atmosphere end up below the current concentrations.

The sooner this happens, the greater the chance of preventing two degrees of warming. But no government has set itself this task.

The EU and the Swedish government have established the world's most stringent target. It is 550 ppm, which gives us a near certainty of an extra 2 degrees C. The British Government makes use of a clever conjuring trick.

Its target is also "550 parts per million," but 550 parts of carbon dioxide alone. When you include the other greenhouse gases, this translates into 666 ppm, carbon dioxide equivalent (a fitting figure).

According to last autumn's Stern report on the economics of climate change, at 650 ppm there is a 60-95 per cent chance of 3 degrees C of warming.

The government's target, in other words, commits us to a very dangerous level of climate change. The British Government has been aware that it has set the wrong target for at least four years.

In 2003 its environment department found that "with an atmospheric CO2 stabilisation concentration of 550 ppm, temperatures are expected to rise by between 2 degrees C and 5 degrees C." Last October, I challenged British Environment Secretary David Miliband over this issue. He responded as if he had never come across it before.

The EU is also aware that it is using the wrong figures. In 2005 it found that "to have a reasonable chance to limit global warming to no more than 2 degrees C, stabilisation of concentrations well below 550 ppm CO2 equivalent may be needed." But its target hasn't changed either.

Embarrassingly for the government, and for left-wingers like me, the only large political entity in the U.K. that seems able to confront this is the Conservative party. In a paper published last month, it called for an atmospheric stabilisation target of 400ppm-450ppm carbon dioxide equivalent. Will this become policy? In my book Heat, I estimate that to avoid two degrees of warming we require a global emissions cut of 60 per cent per capita between now and 2030.

This translates into an 87 per cent cut in the U.K. This is a much stiffer target than the British Government's, which requires a 60 per cent cut in the U.K.'s emissions by 2050.

Guardian Newspapers Limited 2007