(AP) -- Wealthy nations, as history's biggest polluters, should cut greenhouse gas emissions by 40 percent from 1990 levels by 2020, China says in a policy document on climate change. The government also rolled out fresh help for solar power and other "green energy."

The reductions China is calling for are based on the principles of "historical responsibility and fairness," the position paper says, and set a hard line ahead of international negotiations on addressing global warming.

A U.N. conference set for December in Copenhagen aims to draft a new agreement on controlling carbon dioxide and other heat-trapping greenhouse gases that scientists say are causing the Earth to warm. Delegates will meet in Bonn, Germany, next month to begin discussing the text of that agreement.

China's position paper was posted Thursday on the Web site of the National Development and Planning Commission, the country's main economic planning agency.

Meanwhile, the government announced new support for solar and wind power and other .

In a meeting Thursday with provincial officials, the Ministry of Finance promised 38 billion yuan ($5.6 billion) in subsidies to promote wider use of wind and solar power and encourage the use of energy efficient cars and appliances, state-run media reported Friday.

China, which relies on heavily polluting coal for about three-quarters of its electricity, has sought to spotlight its efforts to improve and cut emissions, but has not committed to specific targets in climate talks.

The policy document issued this week gave no specific targets for China or other developing countries, but instead reiterated demands for technology transfers and other support.

Rich countries should provide at least 0.5 percent to 1 percent of their annual gross domestic product to help developing countries upgrade technology, cut emissions and adapt to the consequences of , the document said.

China has welcomed President Barack Obama's commitment to tackle climate change and re-engage in the international negotiations to come to an agreement in December.

But despite that shift, "the developed world has yet to do its due part in tackling climate change," the official newspaper China Daily said Friday in a commentary.

"No solution to fight global warming will be genuine enough, and thus practical enough, if developed countries keep glossing over their historical responsibility on this issue," it said.

The U.S. - which also has not issued targets for reducing emissions - has said that any agreement to combat global warming should require developing countries like India and China to reduce emissions.

Together, the U.S. and China are the world's two biggest emitters of , accounting for 40 percent of the global total.

While visiting Prague this week, Premier Wen Jiabao shrugged off pressure from the European Union for China to commit to cutting greenhouse gas emissions, though he backed EU efforts to reach a new global climate change accord to replace the U.N. Kyoto Protocol, which expires in 2012.

The EU says it will reduce emissions by 20 percent by 2020 and will go to 30 percent if major world nations will make similar cuts.

Experts say emissions must peak in 2015 and then fall by half by 2050 to limit .

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