Beijing - China on Wednesday admitted for the first time that its emissions of greenhouse gases have caught up with the world's longtime top producer, the United States, and said its reliance on coal would make emissions reductions difficult.

"According to our data, China's current total emissions are almost as the same as that of the United States," Xie Zhenhua, a top government economic planner, told reporters.

"Whether or not we have surpassed the US in emissions is in itself not important," he argued in presenting a key policy paper on climate change to the media. "We should look at the issue fairly and from a historic view."

Longtime industrialized nations have a duty because of their historic responsibility for the accumulation of greenhouse gases in the atmosphere to take the lead in reducing them and providing cooperation, financing and technology transfers to poorer, developing countries, China's cabinet said in the White Book.

While the policy paper said China was committed to reducing its greenhouse gas emissions, it also admitted that its reliance on coal, from which it derives two-thirds of its energy, would present a hurdle.

"Its coal-dominated energy mix cannot be substantially changed in the near future, thus making the control of greenhouse gas emissions rather difficult," the document said.

China has set goals to reduce its greenhouse gas production and energy consumption but has failed to achieve them.

Beijing said it wrote the White Book on the principle of "common but differentiated responsibilities" for climate change.

"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," the White Book said.

Experts have long held that China has equalled and might have surpassed the United States as the world's top greenhouse gas emitter, but Wednesday was the first time the quickly developing, most populous nation on earth said it had achieved parity with the world's largest economy.

Beijing has argued, however, that the West bears a greater historical responsibility for global warming and should allow poorer countries to develop their economies and reduce poverty as the world fights climate change.

Xie - the vice chairman of the National Development and Reform Commission, China's top economic planning body - said rich nations accounted for 77 per cent of the global greenhouse gas emissions from 1950 to 2000 while China accounted for 8 per cent from 1904 to 2004.

He added that China's per-capital emissions were a fifth of those in the United States and 20 per cent of China's emissions came from the production of goods for developed countries.

He said rich nations should commit at least 0.7 per cent of their gross domestic products to help poor countries fight global warming.

"Up until now, their spending has been far below that level," he said.

The White Book argued that developed countries should work to adapt to climate change and reduce their emissions "to the lowest degree" while at the same time developing their economies and fighting poverty.

It added that China would do its part through energy conservation, development of sources of renewable energy, increases in nuclear plant construction and reducing emissions.

The policy paper also said China is one of the countries most susceptible to climate change and has already seen decreases in precipitation in northern China and increases in southern and western China while the intensity and frequency of droughts and heavy precipitation has risen.

It predicted drops in agricultural yields and livestock production, increasing desertification, and rising crop and livestock diseases as well as insect blights.

Water supplies were also expected to undergo further drops, it said. (dpa)