More to come

Given the facts that China is one of the world's two biggest greenhouse gas emitters (with the United States) and its economy continues to grow, experts say it will become the target of similar unilateral programs, despite its efforts to bring down carbon intensity domestically.

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"China should better prepare itself for similar cases and work out better tactics, instead of just saying no," Yang said. "This would require extensive research work by think tanks in the country."

EU's move is an alert to China's business sectors that it is time to face the climate challenge seriously. Otherwise, they are bound to face more strains on carbon emissions in future global competition.

"The same is true for the whole country," Yang said. "Now we can still use the developing status to refuse the carbon reduction obligations, but by 2020, China will have to shoulder more responsibilities as a major world power.

"There is not much time left."