For a developed country, the US has quite low GDP output per emissions. See https://en.wikipedia.org/wiki/List_of_countries_by_ratio_of_...

Only Australia (another country full of climate change denialism) and Israel fare worse. Canada is rather comparable.

On the other hand, some European countries (e.g. France, UK) are nearly double gdp per emissions. Even Germany with its relatively large industrial sector has far better GDP per CO2 ton.

That's looking purely at CO2. Not energy.

Why is that relevant?

Either the US has poor energy efficiency (GDP output per energy input) or the US has energy sources that are highly carbon intensive. Both are bad.

I don't think there's a single economist in the world, without significant bias, who doesn't believe that China will be a serious economic powerhouse when it becomes a more developed nation.