The United States outsourced the bulk of its consumer production to China and the latter's emissions are still falling. You don't find that impressive?

A little chemistry:

    CH4 + 2 O2 -> CO2 + 2 H2O - 890kJ/mol
    C + O2 -> CO2 - 393kJ/mol

The relevance of those equations are that CH4 is methane, the principle component of natural gas, C is pure carbon, the principle component of coal and the USA has been transitioning it's energy production from coal to natural gas.

The above equations say if you produce the same amount of electricity with natural has, your CO2 emissions halve. That is the driver of the reduction you point to. It is nice to see, but halve is the best that can happen. Meanwhile if China's continues down it's current path, their CO2 emissions for electricity production will drop to 0.

According to the EIA, the USA has about 18 years of reserves of natural gas at current production rates [0]. The USA has about 70 years of reserves of coal, so this transition to using natural gas is temporary. After about 100 years the USA will run out of both. If you want to see what that looks like, look at the UK.

[0] https://mahb.stanford.edu/library-item/fossil-fuels-run/

China can get to 0 emissions with their approach - replacing coal with solar and batteries. The US cannot do the same with theirs - replacing coal with natural gas.

But of course the countries who would have to pay are precisely the ones that will never sign on that.