Never really thought about it.
Globally the overall numbers are better, mainly thanks to much greater investment in both Nuclear Power and massive Solar Farms/Wind Farms/Hydroelectric generation (on the scale that only Nation States can manage) that, while appalling conservationists who have watched delicate ecosystems get trampled, have reduced reliance on fossil fuels, especially in the U.S., where a combination of high speed rail and EV vehicles has made iC engine vehicles pretty much niche consumer products (pretty much the mirror image of today) with the main users of IC engines being the military and certain agricultural operations (those that are located too far from generation/relay stations).
I would imaginate that Chinese enviroment is even in worse condition than in OTL if it is even possible. China can't feed its 2B population without massive foreign support with any way. It would mean that it has outright exploit its enviroment to really bad condition. Probably every square meter of fertile land is now farmland, every place where is some valuable minerals are turned as polluting mines etc.
Yes, it has Soviet vassal but Siberia can't produce lot of food.