US running ops out of australia. Building bases as we speak

A lot of these nations are trying their best to simultaneously hold the door shut during these Trump years but keep a foot in the door to mend relations thereafter and should sensible Democrats return to power. Still, the volatility of US politics means these nations are forced to keep the US at arms-length because even if we elect another Obama (perceived extremely well by these nations) like El-Sayed, AOC, Talarico, etc. who's to say in another 4 years we won't elect another Trump... ? My guess is they will now expect systemic changes to prevent another Trump-like candidate hijacking the system, which is of course mostly dreaming as that would require major legislation and outright constitutional amendments. Tall order.

Israel isn't part of G20 and this wasn't a leaders summit either.

Too many.

According to this website (which claims IWF data), its currently 8th.

Though China isn't there yet, the share contributed by coal is declining. The reason solar panels have gotten as cheap as they are is thanks to Chinese production.

Just because they aren't making the greatest visible strides yet, they would appear to be gearing up for a big shift. If their push for electric cars is anything to go by, they would appear capable of committing to change.

Meanwhile America and Europe are dragging their feet.
Just because they aren't there yet, doesn't mean we should give up.
Just because you see someone else littering, doesn't mean it's all useless and you might as well not bother with bins anymore.

China has produced more Nuclear power plants than the entire world combined. They have installed more solar than the entire world combined. They have installed more hydro than the entire world combined. Yes, they have a lot of coal as well. Because they are simulataniously trying to raise the standard of living for 1.4 billion people, while meeting their climate goals which are far more aggressive than any other nation.

They also manufacture a lot of things for other countries. An important fact you're leaving out of the discussion here...

China is among the greatest polluters but it is also by a long shot the largest builder of renewable energy plants (solar, wind, you name it). The US on the other side is also among the greatest polluters, and there is also construction of renewable power sources but it is against the opposition from DC. The administration is not even indifferent, it is actively hostile to such projects, trying to prevent them.

China isn't the good guy here but the definitely have invested a lot in reducing the impact of their industrial rise on air quality. That can be seen also by how dramatically air quality has improved in many large Chinese cities.