That is completely wrong.

First, the West and particularly the US are still well ahead of China regarding both historical total emissions and per-capita annual emissions. And regardless of what China does in the future we still need to get our acts together domestically.

Also, China is aggressively pushing low-carbon energy sources on all fronts. Where they are now is not necessarily an indication of where they will be in a decade or two.

A large part of their emissions is the result of stuff they make for us. If we are serious about climate policy, we have to set up trade barriers proportional to greenhouse gases emissions to limit this effect. These policies must be informed by climate science.

Finally, regardless of what the rest of the world does, mitigation depends only on us and how well prepared we are.

Really, there is absolutely no scenario in which it is not a good idea to understand what the hell is going on with our climate.