The UK carbon dioxide pollution is far too high. But per head of population it is half that of the USA.

But it's not true actually that the USA is the worst offender per head of population - that distinction belongs to the United Arab Emirates, though there's not a lot in it. But of coiurse the USA has a lot more heads of population.

That fact comes from ecoworld.com, which has all kinds of fascinating stuff. And it's American, so far as I can see. Americans are the worst polluteors, but also provide some of the strongest voices against pollution.