Going up in smoke

As the biggest seller of carbon credits worldwide, China has made billions of dollars from the Kyoto Protocol's carbon trading mechanism.

The country had attracted thousands of green projects since 1997, when the agreement between 37 developed countries to cut greenhouse gases between 2008 and 2012 was adopted.

As the protocol nears the halfway point, however, experts say China's strong position could be weakened when world leaders discuss revising and expanding the carbon market next month at the United Nation's climate conference in Copenhagen, Denmark.