They might be cleaning up the smokestacks (which is a very good idea considering how much damage the pollution does) but that does nothing about the carbon emissions.
China is catching up the rest of the world in terms of its productive capacity. What other nations did over the course of centuries China is doing in a matter of decades. China also has almost 2 billion inhabitants, which might put its output in context compared to a nation of about 300 million. Cleaning up smokestacks doesn't directly impact carbon, but it helps preserve habitats that do.
Overall, China's strategy is only comprehensible if you take into account its other priorities, namely the empowerment and industrialization of the global south. To combat climate change, the nations with the longest record of causing it should be the ones who draw down their resources, not the ones that are undeveloped and lack basic infrastructure. Much of China's emissions are from their international effort to bring impoverished areas into the 21st century, and if you oppose those efforts then you're basically saying such areas do not deserve to have electricity, paved roads, or clean water.
Instead of depriving the global south of the first chance they have ever had at becoming autonomous and technologically developed, America should be calling upon the European and Japanese governments to massively scale back their military and heavy industry, and contribute a smaller portion of it to building up places in Africa to a dignified baseline of development. This is very unlikely, of course, but not impossible under the right leadership. Climate policy has to be international and can't be used as a cynical way to deny economic progress to the majority of the human species. China is one of the only countries whose policy is (at least currently) reflective of that.
