Gordon Brown’s first big green speech was long on analysis and aspiration, but shorter on action. It was a classic Brown performance, in its strengths and its weaknesses.

His first goal was to show that tackling climate change and creating a low-carbon economy are a high priority for his Government. He seems to have succeeded, to judge by the warm response of most green pressure groups.

Mr Brown accepted the conclusions of the Stern report that meeting the challenge is “both technologically feasible and economically rational; the costs of urgent action are far less than the costs of delay; and the earlier we act, the easier and less expensive our task will be”.

His speech discussed a series of daunting targets, which are not demanding enough for some green groups and have been missed or watered down, according to opposition politicians.

Mr Brown suggested that the target for achieving a reduction in carbon dioxide emissions might have to be raised from at least 60 per cent by 2050 up to 80 per cent for developed countries. A global carbon market, based in the City of London, is the heart of his approach, “harnessing the power of the market to set a global price for carbon”, building on the EU emissions trading scheme.

The trouble, as often with Mr Brown, is when you come to the how. There were lots of challenges, tough decisions and hard choices, even bigger opportunities, and lots of consultations, and forums, not least on yesterday’s intended headline initiative over eliminating single-use disposable plastic bags.

The links and, above all, the costs are vague. It may be possible to halve average emissions from cars by 2030 by applying new technology but what will these cars, and their fuels, cost? The same is true on making homes have a zero-carbon profile. The goals are correct but, again, how and how much?

It is still unclear how we can achieve the goal of ensuring that virtually all electricity and most energy used in heating, cooling and transport will come from low-carbon sources by 2050. Mr Brown reiterated his support for new nuclear power stations, but a detailed policy will not come until the new year. Who will bear the cost of nuclear waste and decommissioning? This will determine the scale of private investment.

The EU has yet to decide how the overall target of one fifth of energy produced by renewables will be divided between countries but, since only 2 per cent of British energy comes from renewables, this is bound to mean a huge increase. Again, how? Offshore and onshore wind farms, tidal energy (particularly from the River Severn) and energy from waste and biomass, all were mentioned in careful terms of future studies.

There was a lot about initiatives by government, business and voluntary groups. What was missing was any sense of what we, as individuals, will all have to do and pay, apart from not using plastic bags. The challenges were mainly general, not specific. That is understandable politically, given that voters are green in theory but sceptical in practice, but to achieve his goals Mr Brown is going to have to move beyond targets and summits and to take hard choices over policies affecting us all.

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