President Hu Jintao's announcement of China's planned "significant cuts" of carbon intensity by 2020 and urgency of assistance from rich countries to help other nations adapt to climate changes shows the country's leadership in pushing for a climate deal at Copenhagen this December, experts have said.

"These announcements should sweep away the canard that China is not willing to reduce emissions," said Daniel Dudek, chief economist of New York-based Environmental Defense Fund.

"A significant reduction in China's emissions would contribute mightily to turning global emissions from growth to decline and it would protect the Chinese people from the worst damages of climate change," Dudek said, adding that 2020 is an important milestone, a threshold scientists say the global emissions must peak if the world is to avoid the catastrophic climate dangers.

"The reduction plan is fantastic, but the major question is how the plan will be implemented in order to really deliver the reductions," said Dennis Pamlin, a Sweden-based environmental policy advisor for several international organizations.

China will have to intensify its domestic actions to realize carbon intensity reduction by 2020, said Yang Fuqiang, director of the global climate change solutions program at WWF.

"To fulfill this commitment, the country will include the carbon-intensity targets, comparable to the current energy efficiency goal, in its 12th and 13th five-year plans (between 2010 and 2020)," said Yang, adding that the new indicator will pave way for more carbon-related economic policies in China, such as levying a carbon tax and fostering a domestic carbon trade market.

"Industries can carry out trade for carbon intensity quotas, which will facilitate for overall carbon emission reductions in China, even though there is no cap for the absolute carbon emissions," said Yang.

And the carbon intensity target is likely to be quantified in the run-up to the Copenhagen climate congress. There are still several rounds of international meetings scheduled ahead of the final negotiations in December.

Yang's view is shared by Yu Hongyuan, an associate professor with the Shanghai Institute for International Studies, who said that China has already started to draft low-carbon economy guidelines and action plans to fight global warming at provincial levels.

"This shows the carbon-intensity goal proposed by President Hu is not a pompous statement, like the emission reduction targets laid out but unachievable by some developed countries, rather, it is a pragmatic target China is already on track to realize," Yu said.

Dudek also said China must set interim targets and have much more frequent compliance steps by enterprises to be sure that the nation is on track to deliver emission reductions.

In the speech delivered to world leaders at the UN climate summit, Hu also urged the developed countries to equip African countries, small island countries, less-developed countries and land-locked countries to adapt to climatic catastrophes.

"Up until now, the developed countries have never realized their promises to help developing countries in terms of financial aid, technology transfer and capacity building," Yang Fuqiang said.

Yang said China may take lead because the technology and experience China, as a biggest developing country in the world, has accumulated can better meet the needs of less developed countries, Yang said.

China, which has a huge rural population, has been conducting research and practice on both the mitigation of greenhouse gas emissions from agriculture and the necessary adaptations to the coming climate changes, according to Dudek.

"At the same time, these practices (helping other countries) would be most efficiently deployed if linked into the global carbon market," Dudek said.

With the carbon intensity reduction, and further improvement of the country's energy efficiency, Yang from WWF estimated that China will be able to achieve 4.5 billion tons of carbon emission reduction between 2005 and 2020, based on the research Yang and his colleagues have been working on.

"This would be the largest ever than in anywhere else," he said.

This will of course pose a big challenge for other developed countries, especially for the US, which has yet to have its domestic climate bill approved by the Senate.