The invasion of Iraq brought to a head a new wave of anti-American feeling around the world. In cartoon terms, the European charge is that Americans are fat, trigger-happy, Christian fundamentalists, opposed to abortion, wedded to the death penalty and determined to drive the largest cars on the planet with some of the cheapest petrol.

In fact the environment is the issue which is going to give America the most trouble, because it resonates with ordinary people in so many countries. The United States does not easily see itself as the villain of the world's environment, as so many others do. Americans look around and see a green and fruitful land, less polluted, less spoiled and less inhabited than many areas of Europe or Asia, and they have a point.

The problem is climate change. America emits more greenhouse gases per person than any other country in the world. Until it was overtaken by China (roughly at the end of 2007), it emitted more than any other country overall, even though its population is just a quarter of China's. That underpins its reputation as greedy, consuming “more than its share” of the world's resources, its people refusing to compromise the world's highest standard of living to save those in poor countries from the effects of climate change. The cars two feet longer than anything you could park in London or Paris, the sport utility vehicles managing only 14 miles to the gallon - all these are brandished as evidence of America's moral failing (although critics never adjust for the smaller size of the American gallon, only 83 per cent of the size of the imperial gallon used in Britain).

There is still a lot that can be said in its defence that is lost in the insults. The first point is the depth of the environmental tradition in American culture. The American reverence for the wilderness goes back before even the explorers who pushed the frontier westwards - back to Native American culture. When I was at school in Washington DC in the 1970s, the curriculum was peppered with lectures about recycling and protecting wildlife, a good couple of decades before that became standard in British schools. “It was America that put environmentalism on the world's agenda in the 1970s and 1980s,” recalled Glenn Prickett, a senior vice-president for Conservation International. “But since then, somehow, the wealthiest and most powerful country on the planet has gone to the back of the line.”

A second point in America's favour is that the environmental laws which it passed in those decades are some of the world's toughest. The 1980 Superfund Act, a tax on petroleum and chemical industries to pay for cleaning up toxic land, and the five separate Clean Air Acts between 1963 and 1990 were very expensive for American businesses and state governments.

The US also moved quickly, when a 1976 National Academy of Sciences report found damage to the ozone layer, to ban chlorofluorocarbons from aerosols, a move resisted initially by the European Union. It was one of the driving forces behind the 1987 Montreal Protocol to ban substances damaging to the ozone layer, and in developing replacement technologies.

What is more, America enforces these laws, even if their application is challenged in court. In contrast, while the EU has been prolific in passing ambitious regulations on environmental standards, the marvel is how patchily they are enforced. The countries on Europe's southern fringe, Greece, Italy, Spain, Portugal - the poorer ones, before the influx of those from the former Soviet bloc - have often been treated with some lenience when they have failed to comply with laws on drinking water standards, cleanliness of beaches, the protection of wildlife habitats.

But then we come to climate change, and America has a more difficult case to make, one where, so far, it has won no worldwide sympathy. The Bush Administration did, in February 2008, say for the first time that the US would agree to be bound by limits on emissions - but only if China and India were too. But that sidesteps their main objection: that the emissions of the developed world have caused the problem and that rich countries should bear the cost of mitigating climate change.

America's best defence is that it would find it much more expensive than would other countries to make those changes to its economy, and if it did so abruptly, there would be an effect on growth that would also hurt other economies, particularly the poorest. Given its size and its reliance on road transport, it is inevitably more dependent on petrol than are smaller, more densely inhabited countries.

The Kyoto Protocol was much easier for European countries to meet, as it coincided with a shift from coal to gas-fired power stations, which immediately reduced emissions. Germany was helped by the closure of many old, dirty East German industries, which scythed through the emissions levels of a united Germany, as well as by the slow shrinkage of its ageing population. Even given those advantages, the EU has not found it easy to make the required cuts. The European Environment Agency, a Copenhagen-based think-tank, predicted in November 2007 that the 15 countries covered by the Kyoto commitment (not including those who joined since 2004), were on course to achieve only a 4 per cent cut in emissions, not the 8 per cent required.

America's proposal to research new green technologies and to export or give them to other countries is also a strong point in its favour. The speed with which it did this over ozone-damaging chemicals was dramatic. In December 2007 Bush signed into law new rules on energy efficiency in cars and houses - the Energy Independence and Security Act. That will slowly, but profoundly, effect change in America towards cars and appliances that use less fuel.

As well as these new federal efforts, some of the states have now been moving on their own to try to encourage behaviour that would reduce carbon emissions. That does not fit the stock image of America as a country which does not care about global warming.

The same phenomenon is true in all developed countries - that people are concerned about global environmental problems, but do not much want to sacrifice their own standard of living to help. It is unfair for countries which, because of the structure of their economy, find these changes easy to accuse America of entirely neglecting something it would find more difficult.

I'll add one final argument, even though I'm conscious that it drives my greenest colleagues to a point beyond anger: there is a moral value in encouraging people's mobility because it encourages their understanding of one another and their ability to work together. Americans' delight in criss-crossing their own country carries a cost in pollution but it springs from the exhilaration of the American project itself, and underpins its success.

© Bronwen Maddox 2008. Extracted from In Defence of America, to be published by Duckworth Overlook on September 11 at £12.99. Buy it for £11.69, p&p free, from Booksfirst: 0870 160 8080 or www.timesonline.co.uk/booksfirst

Tomorrow: what America can do to restore its image

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