They already have ruined the environment here, beyond what most people are willing to believe. And for a long time to come. Preventing further environmental damage by limiting climate change seems to the Chinese leadership like a small gain in comparison to the losses which already have been incurred. Furthermore as Chinese environmental damage accumulates, in relative terms the climate change issue may loom smaller rather than larger.
This simple point is not well understood. Consult the framework from Charles Karelis’s The Persistence of Poverty.
People here talk about the environment more than any place I have been — ever — but they are not talking about climate change.