I agree that CO2 is an imperfect measure and you don’t seem to be making the claim that CO2 has an SNR of 0 (ie it carries no information at all). We seem to agree on the core of your central three paragraphs so I won’t comment on them.

You’ve stated multiple times now that you don’t know any better measures than CO2. So even if there are other measures they’re just as bad or worse. Given this lack of any better metric, on what verifiable evidence are you basing any of your conclusions?

I’m assuming based on the time you responded to me that you are in China so maybe you can elucidate me on how I get this wrong.

The same way you got your conclusions about China’s pollution wrong, by misapplying evidence and jumping to conclusions.

It’s interesting that you should phrase your question that way. The cheap answer would be to point out that you’re not using “elucidate” correctly. You’re missing a preposition. It’s also odd to use “get” instead of “got” here. A corrected version of your sentence might be, “…maybe you can elucidate to me how I got this wrong.” It’s cheap in the sense that personal attacks are easy and do little to advance a conversation. It would be just as silly of me to use your grammar error as evidence that you’re a foreign national as it is for you to use the timing of my posts as evidence of my location.

You might then suspect that I might still be a foreigner who’s studied too much English grammar. That would be correct. It turns out that when I speak my native language, other native speakers can sometimes pinpoint the exact district in Vienna where I was born. These days, none of my neighbors speak German. They love the Sox and rock their “Dunkies”.

Just as in the case of estimating China’s pollution levels, cavalier use of evidence leads to erroneous conclusions.