Barack Obama will take his inauguration oath on the steps of the Capitol on Tuesday as the world looks on in fervent hope of the change he has promised. And nowhere will this be more important than in relation to the environment. He has already given us a flavour of his agenda by announcing a $150 billion (£100 billion) investment in green technology over the next 10 years that will create 5m “green collar” jobs. He has pledged to set an example on clean energy and emissions and his Green New Deal will fight two of the world’s immediate problems: climate change and recession.

Other countries also see the environment as a way of beating the downturn. Japan plans to create 1m green jobs and South Korea will be investing $38 billion in green technology by 2013. Spain plans to link its provincial capitals with a high-speed rail network – laying about 6,000 miles of new track by 2020 – to limit carbon emissions and improve passenger choice.

Unlike the US, the UK has no comprehensive, integrated strategy for the creation of green technology. There have been some welcome, relatively small-scale initiatives on home insulation and renewable energy but no coherent, determined, national initiative. At times it seems as if we are determined to be wedded to a high-carbon economy. And as if to prove the point, the government has now announced the go-ahead for a third runway at Heathrow, claiming it is needed for our country to remain internationally competitive.

This is an unproven claim and I am sceptical of the economic benefits this decision will bring. I am certain, however, of the environmental damage it will cause. Air quality around the airport is already approaching EU pollution limits and, with the operation of a third runway, not only will we be producing unhealthy amounts of nitrogen dioxide, but we will struggle to reach our ambitious – but essential – target of an 80% reduction in carbon dioxide by 2050. It was a deeply disappointing decision.

The Environment Agency, which has consistently opposed the additional runway, has been asked to monitor and enforce air quality limits around Heathrow. It is an ironic position to find ourselves in, but we will be strenuous and rigorous in carrying out our new responsibility, and will do our utmost to protect local people and the environment. Ensuring a watertight system of monitoring air quality is going to be difficult because pollution will come both from aircraft and from all the ground traffic getting to and from the airport, but we’ll be tough.

It is still not certain that the runway will actually get built, of course. Legal challenges will be made; a major planning process will have to take place; and there will be a general election with both opposition parties pledging to reverse the decision. It is impossible to see how this will all play out, but it is now inevitable that the third runway will becomethecause of climate activists in the same way that Twyford Down and other road schemes in the 1990s were under a Conservative government. On this iconic environmental issue, Labour has ended up on the wrong side of the debate.

The government’s committee on climate change has said that it might be possible to continue flying at current levels and still meet the 80% target for carbon dioxide reduction; but this would involve dramatic reductions in emissions from all other areas of life and, in any case, the Heathrow decision would seem to be heading wilfully in the opposite direction. How much better it would have been to have focused on real and sustained investment in our rail network.

There is probably only one way in which the government can get back onto the front foot. Soon it will have to make a decision on the future of coal-fired power generation, and especially on the proposal for a large new power station at Kingsnorth, in Kent. If it insists that coal-fired power can happen only with integral carbon capture and storage in place, developed as part of any new power stations from the word go, it will not only be doing the right thing for the environment but it will help Britain to take a world lead in a crucial green technology.

Even if the world stopped emitting any carbon dioxide at all tomorrow, the effects of climate change – rising sea levels, increasingly erratic weather patterns, water shortages across the world – would continue for 30 years. That’s the scale of the challenge. We have a limited amount of time to turn things round and we must not abandon the task, even in the face of huge economic difficulties.

It so happens that doing the right thing environmentally also makes economic sense. Investing now in a major way in green technology, in renewable energy, carbon capture and storage, rail infrastructure, energy efficiency, the decarbonisation of electricity and waste reduction would create jobs, stimulate the economy and help us to beat the credit crunch and combat climate change.

This is a message that we’ll hear from the steps of the Capitol in two days’ time. Could we please hear it from the steps of Downing Street as well?

Lord Smith is chairman of the Environment Agency and a former Labour cabinet minister

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