On a bad day - which can be hundreds in a year - the ancient city of Linfen in the northern province of Shanxi is environmental hell. Named by the World Bank last year as having the worst air quality on Earth, its 3.5 million people more often than not choke on coal dust; its soil and its rivers are covered with soot, and its Buddhas are blackened and shrouded in a toxic mist.

The cause is Linfen's 196 iron foundries, its 153 coking plants, its unregulated coalmines, tar factories, steelworks and domestic homes, all of which burn cheap, easily accessible brown coal.

Shanxi is the centre of China's vast and growing coal industry, which was pinpointed yesterday by Dutch government scientists as the major culprit, along with the cement industry, in the country's sudden surge to the top of the world's league of greenhouse gas emitters.

In the last six years, the Chinese coal industry, with reserves put at more than 1 trillion tonnes, has doubled production to more than 1.2bn tonnes a year. The country is now building 550 coal-fired power stations - opening at the equivalent of two a week - and in the five years to 2005, electricity generation rose 150%.

But while the Chinese economy has tripled in size in a decade, it has been at the expense of carbon dioxide emissions, which were yesterday put at more than 6.2bn tonnes in 2006, compared to nearly 5.8bn tonnes for the US.

China is well aware of its impact on climate change. Its Himalayan glaciers are melting at an unprecedented rate, its deserts are encroaching on cities in the north-west, and rivers are drying up as a result of temperature rises and over-exploitation. According to the Worldwatch Institute thinktank in Washington, Chinese air pollution from coal-burning cost its economy more than $63bn (£31bn) in 2004, or roughly 3% of GDP.

But China argues that even with its surging economy, it is a relatively minor villain. The carbon footprint of the average Chinese last year was only a quarter of an American, or half that of a Briton.

China's first national plan on climate change, put together after two years of preparation by 17 government ministries, follows western countries in setting ambitious domestic targets to improve energy efficiency by 20% by 2010 and to raise the share of renewables - such as wind and hydropower - to 16% by 2020. However, more than a year into the energy plan, it is proving hard to implement. For another 10 to 20 years, the most populous country on Earth is expected to continue its supercharged growth, then to plateau for a decade or so, before making reductions.

"Compared to five years ago, the environment is much higher up the political and media agenda", said Zou Ji, a climate change expert at Renmin university. "For most people, the concerns are local - about contaminated rivers or filthy air - rather than global, but there is a growing understanding of the economic costs of climate change. Last year, a government study forecast a 37% reduction in crop yields within the next 50 years if current trends continue."

Mr Zou said quantitative targets were "pointless" in China, where data is unreliable. In addition, he said, China is suspicious that the EU often sets unattainable goals for short-term political ends.

"Despite its growing importance to the climate change debate, most people in China are either unaware of or uninterested in climate change. In this respect, China's position today is similar to that of the US or Europe during the 70s, when people first started to be concerned about pollution and the destruction of ecosystems," Mr Zou said.

"We have only just started being concerned about local environmental issues. When we become richer and richer, and feel safer and safer then people will have more time and more resources to pay attention to something not directly linked to themselves."

Yang Ailun, climate campaigner for Greenpeace in China, said the country was slowly waking up to environmental problems, but not necessarily in terms of greenhouse gas emissions . "They are worried about the immediate causes of pollution - like river contamination - rather than global warming. Climate change seems far away," she said. "If the government is really serious about environmental protection, then we need to change our economic structure and reduce our dependency on coal."

Yesterday, reactions to China's emissions were mixed. Christopher Flavin, Worldwatch Institute president, said: "The pace of energy development in China is breathtaking. No other large country has ever built an economy at this speed. This is a critical global indicator and it shows the urgency for action everywhere.

"The Chinese are not going to take a different energy trajectory unless the rest of the world does."

John Sauven, director of Greenpeace, said: "Responsibility for China's soaring emissions lies not just in Beijing but also in Washington, London and Tokyo. The west has moved its manufacturing base to China knowing it was vastly more polluting than Japan, Europe or the US."