There is a massive issue with adjusting for trade though. If you just imagine a country lets call it Green, which has no emissions, and a another country Black, which is fully run on dirty fossil fuels. Now when both countries trade, the Green country imports emissions and the Black ones are lowered. It can be that dirty processes have been outsourced to the Black country or you can just have the Green country do things better. When you take the EU and China you can see both. There are absolutely dirty processes outsourced to China, but at the same time things like electricity are dirtier in China then in the EU.