We have arrived at a moment of decision. It is unprecedented and even laughable for us to imagine that we could actually make a conscious choice, but that is nevertheless the challenge that is before us.

Our home — earth — is in danger. What is at risk of being destroyed is not the planet itself, but the conditions that have made it hospitable for human beings.

Without realising the consequences of our actions, we have begun to put so much carbon dioxide into the thin shell of air surrounding our world that we have literally changed the heat balance between earth and the sun.

If we don’t stop doing this pretty quickly, the average temperature will increase to levels humans have never known and put an end to the favourable climate balance on which our civilisation depends.

In the last 150 years, in an accelerating frenzy, we have been removing increasing quantities of carbon from the ground and burning it in ways that dump 70 million tonnes of CO2 every 24 hours into the earth’s atmosphere.

The concentrations of CO2 — having never risen above 300 parts per million for at least a million years — have been driven from 280 parts per million at the beginning of the coal boom to 383 parts per million this year.

Just in the last few months, new studies have shown that the north polar ice cap — which helps the planet cool itself — is melting nearly three times faster than the most pessimistic computer models predicted. Unless we take action, summer ice could be completely gone in as little as 35 years. Similarly, at the other end of the planet, near the South Pole, scientists have found new evidence of snow melting in West Antarctica across an area as large as California.

This is not a political issue. This is a moral issue, one that affects the survival of human civilisation. It is not a question of Left versus Right; it is a question of right versus wrong. Put simply, it is wrong to destroy the habitability of our planet and ruin the prospects of every generation that follows ours. We now face a universal threat. Though it is not from outside this world, it is nevertheless cosmic in scale.

Consider this tale of two planets. Earth and Venus are almost exactly the same size, and have almost exactly the same amount of carbon. The difference is that most of the carbon on earth is in the ground and most of the carbon on Venus is in the atmosphere.

As a result, while the average temperature on earth is a pleasant 59 degrees, the average temperature on Venus is 867 degrees. True, Venus is closer to the sun than we are, but the fault is not in our star; Venus is three times hotter on average than Mercury, which is right next to the sun. It’s the carbon dioxide.

Here Americans have a special responsibility. Throughout most of their short history, the US and the American people have provided moral leadership for the world. Americans must come together and direct their government to take on a global challenge.

The US should join an international treaty within the next two years that cuts global warming pollution by 90 per cent in developed countries and by more than half worldwide in time for the next generation to inherit a healthy earth.

This treaty would mark a new effort. The Kyoto protocol has been so demonised in the US that it probably cannot be ratified there. Moreover, the negotiations will soon begin on a tougher climate treaty.

The Americans should aim to complete this global treaty by the end of 2009 — and not wait until 2012 as currently planned. There are some who will try to pervert this precedent and use xenophobia or nativist arguments to say that every country should be held to the same standard. But should countries with one-fifth the gross domestic product of the US — countries that contributed almost nothing in the past to the creation of this crisis — really carry the same load as the US?

(The writer is former vice-president, the USA)
IHT