It may be true that the USA has achieved the largest reduction in CO2 emissions in absolute terms. But they’re coming off a very large base. In percentage term

It may be true that the USA has achieved the largest reduction in CO2 emissions in absolute terms. But they’re coming off a very large base. In percentage terms, there are several countries that have done significantly better, including the UK who’s CO2 emissions are now 38% below 1990 levels (and 25% below 2012 levels!) despite significant population growth. While US emissions have, by some measurements, dropped in the past decade, they are still well above 1990 levels.