GHGSat is a Canadian company though it has an agreement with ESA to enable data sharing as part of the Third Party Mission Programme. Their first demonstration satellite could detect CO2 but the following five satellites were optimised for methane detection. Presumably this was because it is much easier to detect methane. A quick search doesn't reveal any technical details on the new GHGSat-C10 sensor. However, it is basically the same as the previous ones but it has been optimised for detection of carbon dioxide spectral features instead.

I was going to say, this is already a thing. The refinery I work at tries to only burn their flairs on cloudy days to avoid detection and fines