Xie Zhenhua, vice minister in charge of the National Development and Reform Commission (NDRC), China's top economic planner, made the remarks at a press conference.

China's State Council, the Cabinet, announced Thursday that the country is going to reduce the intensity of carbon dioxide emissions per unit of GDP in 2020 by 40 to 45 percent compared with the level of 2005.

This is a "voluntary action" taken by the Chinese government "based on our own national conditions" and "is a major contribution to the global effort in tackling climate change," the State Council said.

Vice Foreign Minister He Yafei also attended the press conference. "China made the emission cut target without financial and technological support from developed countries. This is not only for the country's own sustainable development, but also for the benefit of all the mankind," said He.

However, China is still hoping developed countries would take actions as soon as possible, He said, adding that the Bali Road Map has set binding targets and actions on emission cut, investment and technology for developed countries.

China faces huge pressure and special difficulties in controlling greenhouse gas emission, as the country has a large population and relatively low economic development level and is at a critical period to accelerate industrialization and urbanization, Xie said.

"It demands great courage for the government to announce such a target," said Yu Jie, an official in charge of Climate Group's policy and research. The Climate Group is a British-based non-governmental environmental organization.

As a developing country, China still faces various problems in both economic and social development, and it is not easy to make such a commitment, Yu said.

The announcement of China's carbon emission target has broken one of the deadlocks challenging the upcoming Copenhagen summit, she said. It is also an answer to President Hu Jintao's promise at the September United Nations climate summit in New York that China would cut emission intensity by "a notable margin" by 2020 from the 2005 level.

China's target is made after scientific research and calculations, combining the efforts to both tackle climate change and promote social and economic development, said Yao Yufang, professor at the Institute of Quantitative and Technical Economics under the Chinese Academy of Social Sciences (CASS). "Any party that asks China for higher cut is acting unreasonably."

China can and will achieve the target if the country endeavors to improve energy efficiency, promote the development of renewable energy and optimize industrial structure, Yao said.

"The country has set a specific quantitative target far beyond the Bali Road Map demands for developing countries, which reflects China's sincerity to make the Copenhagen summit successful and its commitment to tackle the climate change," said Pan Jiahua, director of the CASS Research Center for Urban Development and Environment.

Li Gao, an NDRC official and a key climate change negotiator representing the Chinese government, said 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."