China is a signatory to the international treaty, which seeks to prevent global climate change. But it is not required to meet mandatory carbon dioxide (CO2) reductions targets, unlike signatory developed nations.

Under the scheme, China - the world's second-largest emitter of carbon dioxide behind the United States - is required only to make a commitment to cut its pollution. Beijing's non-binding reductions were one of the reasons Washington cited in refusing to join the scheme.

Although China does not face compulsory cuts, Mr Zhang predicted the Kyoto Protocol would generate diplomatic pressure on Beijing and provide new momentum to the mainland's growing environmental movement.

Mr Zhang said: 'Before the protocol came into effect, countries could shrug off their responsibility. But now with most of the world adopting concrete measures, China will have to do so also.'

Mainland researchers have already begun assessing the economic impacts if Beijing were to commit to pollution targets, he said. In the past decade, Beijing has been aggressively adopting clean-air technologies and improving its energy efficiency, dramatically reducing the growth rate of its pollution.

However, experts believe the mainland's emission rates will continue to rise because of its growing economy and the heavy reliance on coal, which generates 75 per cent of the nation's energy.

In a potential sign of things to come, environmental activists in Beijing organised a rally at Jinshan Park recently, urging the public to conserve energy and the world to support Beijing's pollution-cutting effort.

Mainland produces one-seventh of the world's carbon dioxide emissions, according to the International Energy Agency. In 1990, the mainland emitted an estimated 2.289 billion tonnes of CO2, increasing to 3.307 billion tonnes in 2002, as its gross domestic product grew 204 per cent.