It was the first time the central government had publicly acknowledged that China may have passed the US to become the world's biggest greenhouse gas emitter.

'Based on information we have at hand, our total emissions are roughly the same as the US,' Mr Xie said at the launch of the country's first white paper on tackling climate change.

International research institutes and experts have said for two years that China's output of carbon dioxide, the key greenhouse gas, had surpassed that of the US, given that the latest data on China's greenhouse gas emissions was from 1994.

But Mr Xie said: 'Whether or not we have surpassed the US is not in itself important.' He repeated China's stance that it was only fair to consider historical and accumulated emissions in determining whether developed or developing countries should play a bigger role in the global fight against climate change.

The white paper says: 'Developed countries should be responsible for their accumulative emissions and current high per capita emissions, and take the lead in reducing emissions, in addition to providing financial support and transferring technologies to developing countries.'

Mr Xie said China's per-capita emissions for its 1.3 billion people remain much lower than those of rich countries, and was about a fifth of the US average. 'As China is in the process of industrialisation and urbanisation, it is fairly natural that the country's greenhouse gas emissions grow very fast,' he said.

He also said it was not fair for China to take responsibility for emissions generated on behalf of countries that consumed Chinese exports, which accounted for 24 per cent of the country's total emissions.

Both the white paper and Mr Xie played down the growing criticism over China's refusal to accept a mandatory target in cutting emissions.

'There is no doubt that under the Kyoto Protocol, developed countries must take the lead in reducing their greenhouse gas emissions,' Mr Xie said.

Under the UN-sponsored treaty, developing countries are not obliged to accept mandatory caps, but the US has refused to ratify it, citing the framework's failure to hold China and India more responsible.

'But regardless of the results of international negotiations and how much developed countries honour their commitments, China from its own perspective must realise sustainable development,' Mr Xie said. 'We must save energy, raise energy efficiency, develop renewable energies and adopt measures aimed at reducing greenhouse gases.'

He said the financial turmoil should be viewed as an opportunity for China as well as the whole world to carry out economic restructuring, promoting environmentally friendly technology and cutting pollution.

'Tackling climate change and the financial crisis is not contradictory,' he said. 'We will seize the opportunity to increase domestic demand and funding on energy efficiency. We will have to solve climate change and environmental problems through development.'

Mr Xie said developed countries should contribute at least 0.7 per cent of their gross domestic products to help developing countries fight global warming.

Analysts said the release of the policy paper as well as recent remarks by mainland officials were part of Beijing's strategy amid intense negotiations on a successor to the Kyoto Protocol, which expires in 2012.

An international climate change seminar on technology transfer organised by the UN and China will be held in Beijing next week, and delegates from more than 190 countries will participate in another key UN conference on climate change in Poznan, Poland, in December.

Yang Ailun , from Greenpeace China, said the white paper was basically a review of the government's achievements in tackling climate change in the past few years.

'While it may not have much new information, it is clearly aimed at highlighting China's progress in cutting emissions ahead of international negotiations,' she said.

Moving on

The mainland's dependence on coal-fired power plants is complicating the fight against climate change, but the sector is in the firing line as authorities battle to reduce emissions and increase reliance on renewable energy

Throughout the mainland last year, authorities shut down: 11,200 coal mines

The energy saved by key enterprises in 2006-07 equalled: 147m tonnes of coal

From 1980 to 2007, the proportion of coal used to produce energy fell from 72.2% to: 69.4%

In the same period, the proportion of renewable energy grew from 4% to: 7.2%

From 2005 to 2010, energy consumption per unit of GDP is expected to drop: 20%

SOURCE: CHINA'S POLICIES AND ACTIONS ON CLIMATE CHANGE