Cheng Siwei, a renowned Chinese economist and a former senior legislator, said China is estimated to reduce the proportion of fossil fuel in total energy mix from the current 91 percent to 85 percent in 2020.

Cheng, chairman of the International Finance Forum and former vice chairman of the Standing Committee of China's National People's Congress, made the remarks at the ongoing World Economic Forum's annual Summer Davos meeting in the northern Chinese city of Tianjin.

China needs to improve fossil energy efficiency and also develop new energy, Cheng said. He cited his research results as saying that pollution cost 34.5 percent of the gross domestic product in 2005.

China is also committed to promoting carbon trade, he said. "The critical problem now is to find the most suitable carbon trading market."

The economist also proposed carbon tax to promote sustainable growth.

"We are suggesting imposing carbon tax on thermal power plants and using the revenue to subsidize solar and wind energy development," Cheng said.