The pledge, announced Tuesday as part of China's Annual Report on Policies and Actions to Address Climate Change, comes just ahead of the U.N. climate change conference in Cancun, Mexico, which begins Monday.
In announcing the report, Xie Zhenhua, deputy director of the National Development and Reform Commission, said China was likely to have cut emissions of carbon dioxide by approximately 1.5 billion tons during its 11th Five-Year Plan period (2005-10). He attributed the reduction to the government's energy-saving and emission-reduction investments.
"The size of the emission reduction is greater than any other country in the world," Xie said, China's state-run news agency Xinhua reports. "This is China's contribution (to preventing global climate change)."
Under the five-year plan, China sought to reduce energy consumption per unit of gross domestic product by 20 percent compared with 2005 levels by the end of 2010.
As a last-ditch effort to achieve those pollution-reduction targets, local governments resorted to enforced blackouts.
China, the world's top emitter of greenhouse gases, announced last year plans to cut greenhouse gas emissions per unit of gross domestic product by 40 percent to 45 percent by 2020 from 2005 levels.
The NDRC is laying out plans for the 12th Five-Year Plan (2011-15), which covers energy saving and environmental protection, new energy development and ecological construction.
While details of the plan are scheduled to be announced in a few months, observers expect the new law to also include firm, legally binding targets for improving carbon intensity.
As for the Cancun conference, Beijing said it opposes any draft that hasn't been fully discussed or recognized by member countries as the basis for negotiation.
Xie urged developed nations to take responsibility for their cumulative emissions and high per capita emissions.
"The developed countries should take action first to mitigate climate change," he said.
For the Cancun climate talks to succeed, Xie said, developed countries should agree to transfer technology to developing nations such as China and be the first to cut emissions.
"Developed countries need to take the lead in massively cutting their green house gas emission in order to give further development space to developing countries," Xie said, The New York Times reports. "Developing countries in particular should be concerned about achieving tangible results with regard to funding and technology transfer issues."