[trashtoss]

This is more or less what will happen.

In addition to (eventual) climate change China has been making itself increasingly unlivable due to conventional pollution (in all forms)...but the leadership there has always seen this as a temporary cost that must be borne to catch up with the west.

Internal pressure will already force China to do something sooner rather than later; handling the problem is a good way to consolidate power internally and thus tackled enthusiastically.

Throw in the USA voluntarily ceding its position of world leadership and it's an opportunity to go from barely-tolerated semi-pariah to increasingly-respectable world leader.

In particular expect China to "save" Africa once the worst begins. But, not immediately; groundwork is already being laid, but right now they can afford to be patient.