BBC: China has pledged for the first time to take firm action on climate change, telling a UN summit that its emissions, the world's highest, would soon peak.
Vice-Premier Zhang Gaoli also said China would make its economy much more carbon efficient by 2020.
US President Barack Obama said climate change was moving faster than efforts to address it, and the US and China had a responsibility to lead other nations.
The summit was the largest high-level climate meeting since 2009.
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