BEIJING, March 2, Xinhua -- U.S.-China climate change cooperation was "enormously important" in reaching the historic Paris agreement, the United States special envoy for climate change Todd Stern said here on Wednesday.

"Climate change has become a real pillar in the bilateral relationship over the last few years," said Stern, who is in Beijing to meet with his Chinese counterparts to discuss the implementation of the Paris agreement and continued bilateral cooperation.

Hailing the two countries' rapid progress of cooperation in climate change since 2009, Stern highlighted cooperative mechanisms such as the climate change working group and dozens of cooperation initiatives.

During President Xi Jinping's visit to the United States in September last year, the two heads of state issued a joint statement on climate change, reiterating their resolve to work together toward an ambitious and successful outcome of the climate conference in Paris.

"That statement outlines a number of understandings between the U.S. and China and was a huge jolt of momentum that gave countries the belief that this agreement will actually happen", said Stern.

The Paris agreement, approved by envoys from nearly 200 countries in December last year, still needs to be signed by 55 countries constituting at least 55 percent of CO2 emissions,to enter into force, according to Stern.