Leading article: The people's warning... we need urgent action on climate change

Grass-roots pressure pushed this issue up the agenda. And it will be grass-roots pressure that keeps it there

This was a week in which we saw more clearly than ever the damage our way of life is doing to the planet. Sir Nicholas Stern's report on the economic impact of climate change revolutionised the debate about global warming. We now know that the cost of not acting to tackle climate change could by the end of the century be 20 times the cost of carrying on as we are. It is no longer a question of whether we can afford to reduce our emissions. The fact is that we cannot afford not to.

A report on the future of global fish stocks by an international team of scientists was just as blunt. It revealed that stocks could collapse entirely within 50 years if commercial fishing is not curbed. This was a Stern report for the seas. Indeed the two areas - climate change and the state of the oceans - are linked. One of the reasons why fish stocks are thought to be under pressure is rising sea temperatures. And in both cases, vested interests - fishermen and the oil industry - have for too long distracted our attention from the urgent need to modify our behaviour.

But this was not a week without hope. Sir Nicholas's report, despite its dramatic conclusion, was no counsel of despair. It demonstrated very clearly that if we spend 1 per cent of global GDP now to reduce our emissions, we can still enjoy formidable economic growth over the long term. Sir Nicholas thus nailed the lie that reducing our carbon emissions would mean regression to feudalism.

Our politicians are, of course, all now fighting for ownership of this issue. At the launch of the Stern report Gordon Brown stated his desire to put Britain in the forefront of the struggle against climate change. Mr Cameron has built his leadership of the Conservative Party on the platform of environmentalism. And our outgoing Prime Minister was yesterday pressing the German Chancellor, Angela Merkel, to make the struggle against climate change a priority during Germany's forthcoming EU presidency. Next week's summit in Nairobi to resume the negotiations for a successor to the Kyoto protocol will provide the opportunity for more political manoeuvring.

But for all this encouraging evidence that our leaders are waking up to the scale of the problem, we should remember that it was grass-roots pressure that pushed this issue up the agenda. And it will, no doubt, be grass-roots pressure that keeps it there. A mass rally, organised by the Stop Climate Chaos coalition, will take place in Trafalgar Square today. The range of groups represented - from the Women's Institute to Surfers against Sewage - will be formidable. A host of voices from different backgrounds will gather to deliver a firm message that urgent action is demanded.

There is growing pressure from the general public, too. Stern seems already to have made an impact. According to a poll this week, 53 per cent of Britons agree that the Government should impose higher taxes on activities that cause pollution, even if this means the end of cheap flights and makes motoring more expensive. But there are also lingering suspicions. Sixty-two per cent of those questioned believed our politicians' interest in green taxes is motivated more by raising revenue than improving the environment. It will be a challenge for our politicians to convince the public they are genuine in their concern for the planet. Mr Brown in particular, if he is to be the next Prime Minister, must demonstrate that he is serious.

Climate change is an issue that cuts across traditional political loyalties, class affiliations and economic interests. Everyone has an interest in the future of the planet. Our leaders must keep this in the forefront of their minds in the crucial months and years to come.