So this is pretty misleading. The reason China's emissions are so high compared to everyone elses is that everyone else has moved their production to China. That Sony Playstation your buying is produced in China, so although it's emissions are going up, its actually because of the consumption of Europe and the collective West. Which is to say, China may be emitting, but it is emitting on everyone's behalf.
Seconldy, China's per capita emissions are MUCH lower than the US - about 25%.
Thirdly, China implemented the most effective emission program ever - the one child program.
Historically, the country lease likely to ratify international conventions is the US (because of its congressional approval system). The reason Japan pulled out of Kyoto was because its main economic rival - China - wasn't a signatory. The US sets a bad example for everyone by not ratifying these things, yet insists on being involved.