China lags, not leads. There is an enormous amount of misinformation in this space -- exporting large numbers of solar cells does not mean you are cutting emissions at all, it is a completely different metric.
For the record, China gets half its energy from coal, about 20% from oil, about 15% from natural gas. It is not leading in any sense. They are massively investing in new oil fields, fracking, and deep water drilling, they added 225 new oil fields, they are building out new coal plants and new natgas pipelines. But I guess because they export a lot of solar panels, they are now "leaders" in CO2.
Their long term CO2 goals are in terms of ratio of GDP to CO2 output, not in absolute terms, so their promised 60% decline in that ratio by 2060 allow them to quadruple the emissions if their GDP continues to increase. They also lead in paying people like Kerry (actually his wife and other family members) to whitewash their climate goals.
That is China leading.