China has great expectations for the Copenhagen climate change conference, which must be a success in order to launch measures to avoid calamitous global warming, Chinese Vice Foreign Minister He Yafei said on Sunday.

Government ministers were arriving in Copenhagen over the weekend to work for an agreement on two draft texts that emerged from a week of discussions at the UN climate talks amid expectations that negotiators from over 190 countries will seal a deal to fight climate change.

"Climate change is a challenge the whole global community faces, failure in Copenhagen climate conference is not an option," He told Xinhua in an interview.

The Chinese official promised that "as a big country, China will do its share, so we've taken a constructive and positive approach in the Copenhagen talks and elsewhere."

Last month, China announced that it would reduce the intensity of carbon emissions per unit of its GDP in 2020 by 40-45 percent from 2005 levels. Later this week, Chinese Premier Wen Jiabao will join more than 100 heads of state and government in Copenhagen to attend a climate summit.

Premier Wen will expound China's policy, action plan and proposals on climate change, he said, adding that Wen's participation demonstrates the importance China attaches to the issue of global warming and the climate talks.

Progress has been made in the first week of talks, but negotiating groups are still wide apart on some key issues, such as emission cuts by developed nations and financial support for developing nations, he said.

At a UN panel of climate, scientists were proposing a 25-40 percent cut in carbon emissions by rich nations by 2020 in order to put global warming under control, but the commitments made so far by developed countries collectively amount to only a 16-18 percent cut, he said.

For funding, UN data put developing nations' needs at 100 billion U.S. dollars annually to cope with the impact of climate change, but rich nations were proposing only 10 billion dollars in the next three years and no mid-term and long-term targets were offered, he added.

"It's time for the developed nations to show their political will and turn their political will into substantial emission reduction targets," the Chinese official said.

He said China is doing no less than other countries, and even better, in combating climate change. He cited China's carbon intensity reduction target, saying China aims higher than developed countries.

Carbon emissions per unit of GDP in developed countries were reduced by 26 percent from 1990 to 2005 and will decrease by 30-40 percent by 2020 under their current commitments, but China has pledged a 40-45 percent cut, he said.

"China's efforts are unconditional and not tied to emission cuts by other countries. China has made remarkable contributions to the global fight against climate change," he said.

"China will continue to work with other countries to push for a successful outcome of the Copenhagen conference," he added.