Environmental experts have welcomed a pledge by a leading Chinese climate change negotiator that China will help bring about a meaningful result from next month's climate change summit in Copenhagen.

But they warned all parties still had a long way to go before reaching a consensus that they could sell to their own people.

Li Gao, an official with the National Development and Reform Commission (NDRC) and a key climate change negotiator representing the Chinese government, told a forum in Beijing Tuesday: "We will try to make the summit successful and we will not accept that it ends with an empty and so-called political declaration."

Li was speaking at the Sohu Green Forum, two weeks ahead of the long-anticipated 15th Conference of the Parties of the United Nations Framework Convention on Climate Change (UNFCCC) from Dec. 7 to 18 in Copenhagen, Denmark, where representatives of about 190 countries are expected to renew GHG emissions reduction targets set by the UNFCCC Kyoto Protocol, the first stage of which is to expire in 2012.

It is also expected to outline the post-2012 negotiation path.

However, pessimism has set in over the outcome because the United States, a major UNFCCC party, will attend the summit without any domestic legally binding document on quantified targets for reducing carbon dioxide emissions.

Dr. Yang Fuqiang, director of the Global Climate Solutions of the WWF International, said to make the summit successful, each nation should make an investment, small or large, a declaration and national action plan.

He said climate talks actually "stand on a political and moral platform."

"There is not a country willing to say it is not going to make efforts to combat the climate change due to the moral nature of it," he said.

The UNFCCC was not like the World Trade Organization (WTO) where no morality but interest was involved and nations felt free to criticize others, he said.

Yang said although the U.S. did not sign the Kyoto Protocol 12 years ago, it still had to be actively involved in the climate talks under the UNFCCC.

China should also find major points of agreement with other large developing countries so that they could negotiate as a bloc.

"Talks, whatever multilateral or bilateral, can promote the UNFCCC negotiations," said Yang.

"It is normal that major developing countries, such as China, India and Brazil, may have different views on climate change, as they all seek their own interest, but they still agree on larger issues."

Chen Ying, a senior research fellow of the Research Center for Sustainable Development under the Chinese Academy of Social Sciences (CASS), said there was a transitional process before international treaties were accepted domestically.

This had hampered the course of international climate talks, because, for example, an international treaty could only be legally effective in the U.S. after the Senate approves it.

"All parties have to play a multiple game both domestically and internationally," said Chen.

On Tuesday, Li Gao said, "The Kyoto Protocol and the Bali Road Map have always been China's bottom line in international climate negotiations."

The Bali Road Map, agreed by UNFCCC parties in 2007, laid out a two-year process to finalize a binding agreement in Copenhagen. It covers climate-related aspects such as emissions cuts, mitigation, forestation, adaptation, financing and technology transfer.

Li said all parties should negotiate under the framework of the Kyoto Protocol and the Bali Road Map, "or else the conference would be futile."

Climate negotiations so far, he said, had "made some progress, but are seriously inadequate."

The Kyoto Protocol, signed under the UNFCCC regime in 1997 by most UNFCCC parties except the United States, requires developed countries to set clear targets for emissions reductions. The European Union, Canada, Japan and Australia, among other developed nation signatories, all set respective targets.

An unnamed senior U.S. official reportedly said Monday that his country would reveal specific targets soon, so that all nations would put their emission targets on the table of the Copenhagen meeting.

The United States is under pressure from other nations as the American Clean Energy and Security Act (ACES), aiming to mitigate the effects of climate change, is unlikely to be passed by the Senate this year.

Many U.S. lawmakers worry that the bill, requiring a 20-percent cut in GHG emissions from the 2005 level by 2020, will hurt the economy, although the emissions reduction target was still viewed as "too weak" to tackle the dangerous consequences of climate change, observers said.

Despite all the difficulties ahead, Li said financing offered by developed nations and technological transfer had made some progress, which paved the way for success for the conference.

However, Li said China "will not accept any separate legal document" that put the Kyoto Protocol aside.

Observers say although some developed countries such as the United States cannot publicly deny the validity of the Kyoto Protocol, they could use various hidden means to make it void and legally useless, and let another legal document, in line with their own interests, replace it.

"Abiding by the Protocol and adhered to the UNFCCC-envisioned 'common but differentiated responsibilities' is a matter of principle," Li said.

Discussions on climate change with EU leaders were expected at the regular China-EU meeting later this month, and talks among developing countries were also expected to result in agreed stances at Copenhagen.

"Parties can speak louder and confidently if some of them speak in one voice," Li said.

China and the U.S. signed a memorandum of understanding encouraging cooperation on climate change and cleaner energy in July.

During U.S. President Barack Obama's visit to China last week, the two sides signed a joint statement in Beijing after talks between Obama and Chinese President Hu Jintao, agreeing that "the transition to a green and low-carbon economy is essential."