United States

THE White House offered a cool response to the review, acknowledging that it was a "contribution'' to the study of global warming but declining to endorse its findings.

The US energy industry was less cautious, accusing Nicholas Stern of producing a report that owed more to "science fiction'' than economic reality.

"The Stern report is fun with numbers for political purposes. It's easy to make guesses; it's harder to pin down reality,'' said an industry spokesman.

Analysts in Washington said the report demonstrated the difficulty of forecasting the economic impact of climate change. "When it comes to the science of climate change, we hear a lot about consensus but the consensus argument disappears when you move into the economic cost of global warming. You can find almost as many benefits as you can costs'' said Jerry Taylor, an expert in energy policy at the Cato Institute. "The Book of Revelations scenarios offered in the press don't stand up.''

Although President George W Bush has asked for more funds to be spent on energy research next year, the federal government currently spends just half as much on the subject as it did in 1979.

The Bush administration believes that research into alternative energy sources - such as hydrogen fuel cells - offers a better long- term solution than increased regulation or new carbon taxes. Al Gore, Gordon Brown's new environmental adviser, argues that "we already know everything we need to know to effectively address this problem'' but the reality of American politics means any proposal to impose a "carbon tax'' on petrol would be unpopular. Motorists, long accustomed to cheap fuel, were outraged when petrol hit $3 ( pounds 1.58p) a gallon (42p per litre) in the summer.

Environmental campaigners hope the report will increase pressure on the administration to change. "Finger-pointing at China and India won't do anymore, the US, the world's largest economy, has to lead,'' said Philip Clapp, of the National Environmental Trust.

China

CHINA faces a grave environmental crisis of its own, but is also potentially the greatest contributor to global warming because of the size of its population and the rise of its economy. It produces a sixth of the carbon dioxide emissions per head of population that the United States does. But if its economic growth continues and its emissions per head come to match America's, it would require an entirely new planet to sustain it, according to one estimate. Meanwhile, it is already seeing the consequences. Glaciers on the Tibetan plateau are set to shrink by more than a quarter by 2050 at current rates, reducing China's fresh water supply by 20 to 40 per cent in the next 50 to 100 years.

China also requires a huge growth in energy output to meet the needs of its industries and keep its growing and still poor population in work. It is building a new coal-fired power station every week.

Its leaders are now deeply concerned about the environmental costs but there are limits to how far they can implement "green policies''.

In 2002, the Government set a target of 10 per cent for reductions in sulphur emissions by 2005. In fact, they rose by 27 per cent.

Jeanne-Marie Gescher, a British business consultant in Beijing specialising in the environment, said the options for China were narrower because of the relative poverty of its population.

"China takes the view that global warming is primarily the result of the industrialisation of the western world,'' she said. "There's a sense that because China didn't create the problem it shouldn't have to tackle it until America does.''

China has pursued economic growth in the past 25 years with a passion that only decades of hunger and poverty can produce, but with little thought to the consequences. But for every unit of gross domestic product, China uses five times as much energy as the United States and 11 times as much as Japan.

The figures for water usage are similar, leaving large parts of the country with increasingly noticeable shortages. It also relies heavily on coal, the dirtiest form of energy, to generate electricity, which is responsible for the sulphur emissions which have won China the dubious honour of having 16 of the world's 20 dirtiest cities.

India

INDIA did not react officially to the report but experts blamed the West for any potential environmental apocalypse. Vasant Gowarikar, a former scientific adviser to the prime minister, said Western countries were responsible for global warming and suggested they put in more effort to "undo'' past harmful effects.

"India should not be made part of the gang responsible for global warming. It is a phenomenon affecting Western nations more,'' he said.

A report by the Delhi-based Tata Energy Research Institute declared that while developing countries are more vulnerable to climate change, their contribution to the greenhouse problem was "much smaller'' than that of developed states.

Historically, the study declared, developed countries were responsible for more than 60 per cent of greenhouse gases responsible for polluting the atmosphere over the past century.

Rajendra Pachuri, the head of the institute and also chairman of the global Inter-governmental panel on climate change said India remained "highly vulnerable'' to the impact of human-induced climate change.

However, India has problems of its own making. An ongoing population explosion has placed great strain on the environment. Industrialisation and urbanisation have created more than 20 cities with populations of at least a million.

Urban air quality ranks among the world's worst. Sources of air pollution, India's most severe environmental problem, come in several forms, including vehicular emissions and untreated industrial smoke.