China has much lower CO2 emissions per capita than the USA. It's just a lot of people.

Here's the list: https://www.worldometers.info/co2-emissions/co2-emissions-pe...

Actually I am slightly surprised that the US isn't right at the top (excluding middle eastern countries). It's actually just behind Canada and Australia.

Still kind of mental that your per-capita CO2 emissions are 3x higher than the UK.