Leading article: Leading the world – in hot air

Just as New Labour's "new dawn" was giving way to the harsher light of hard work nine years ago, Tony Blair appointed Jonathon Porritt to chair a new Sustainable Development Commission. It was an inspired appointment. Mr Porritt has a remarkable record of a lifetime's commitment to, and technical knowledge of, the green cause. The commission was a visionary idea, albeit labelled with the stodgy concept of "sustainability" – a way of describing the central imperative of environmentalism, namely that human activity should not deplete the earth's capacity to sustain future generations.

This is the key to viable green politics: how to reconcile the square of economic growth with the circle of protecting the environment. It is the theme on which Mr Porritt has focused, including in his recent book, Capitalism as if the World Matters.

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Yet Mr Porritt is now stepping down as chair of the commission, saying, as we report today: "We've wasted too much time and people know we need to move a lot faster." And the commission will publish a report this week that puts the Government in the stocks for its impending failure to meet a series of important targets. Speaking to The Independent on Sunday, Mr Porritt says: "We have a terrible record of leading the world on rhetoric and then failing to deliver in our own backyard, and that's particularly true on climate change."

Mr Blair's rhetoric and vision was important, but it was only the start of what was needed. Towards the end of his time at No 10, the rhetorical machine was increasingly cranked up, but, as Mr Porritt suggests, the follow-through was wanting. Gordon Brown never had the rhetoric, or the plausible appearance of conviction, but he did create the Department of Energy and Climate Change under Ed Miliband, and last week he set out Britain's preparations for a global deal at the Copenhagen summit later this year.

For nine years, though, progress has been too slow. One of New Labour's failings has been its "Year Zero" approach to policymaking, allied to an attention span that would make life difficult for a butterfly. Mr Porritt points out that Lord Adonis, appointed Secretary of State for Transport earlier this month, is an enthusiast for the continental model of using public transport and bicycles for more urban journeys. Yet that made sense in 1997, if not before, and John Prescott committed Labour to such a policy even before the new dawn broke.

That is a small example, but it applies across the piece. Sustainability requires a shift in the rules of capitalism, the most important being to put a higher price on carbon, in order to use market forces to reduce the output of the gases that cause climate change. That is how higher standards of living can be reconciled with preserving the eco-system. That is how the apparent oxymoron of green growth can be achieved. Not by tacking on green gestures as an afterthought to policies designed to promote growth, with the implication that we will forget them in times of recession, but by re-pricing the measurement of growth to take into account its environmental cost. The creation of Mr Porritt's independent Commission was an attempt by Mr Blair to hold himself and his Government to account for achieving that fundamental change. Of course, it has not been a complete failure and, as an optimistic green newspaper, we prefer to see the glass as half full. Much has been achieved, but it is now time to step up the pace.

Not least because the global situation has changed. It was always the case that "environmentalism in one country" made no more sense than the socialist equivalent. It would have been better if Britain were on course to meet its target for a 20 per cent cut in carbon dioxide emissions by next year. As Mr Miliband's brother David said when he was Secretary of State for the Environment, it would be valuable to "set an example" to the rest of the world, as well as being in our self-interest to gain first-mover advantage in green technologies and markets. But it would hardly make any difference to global outputs of carbon dioxide, with coal-fired power stations being built in China faster than they can be counted.

Now, however, a new US President has transformed the prospects for a global deal at Copenhagen: the Chinese would only ever act if the world's largest polluter, America, would. The world recession also gives us a chance to start to shift towards low-carbon capitalism.

Britain could play an important role in helping to broker such a deal, but only if, nine years late, Gordon Brown and Ed Miliband heed Mr Porritt's warning and finally make up for lost time.