In some ideal world - yes. In the real world that number can be easily cheated and hard to verify, and hard to translate into emissions, due to different tech,

In some ideal world - yes. In the real world that number can be easily cheated and hard to verify, and hard to translate into emissions, due to different tech, different fuel composition, different usage patterns and so on. So estimate, then use estimate to estimate a bigger picture and on and on, introducing errors every time and never being sure about base numbers, if they are true or fake. We can't cheat or fake CO2 level in the atmosphere. You can plop a spectrometer in the middle of Beijing and no CCP can alter that number (there was a fun permanent scandal similar to this, when US embassy in China was measuring air pollution daily and published it in Xitter, CCP was furious). No politicians at COP9000 can sit together and fudge some numbers to make their work look good and important. It's just there, in every place on this planet, easily measurable by everyone.