What's missing from the 9/11 "CO2 drop" data is - what is the statistical day-to-day variation in CO2 level?
We know that temperature, pressure, water vapor, etc. all vary from time to time and place to place. Do we really think that CO2 is a constant? Is the "2% drop" statistically significant?
Maybe the answer really exists, but it hasn't yet come to the surface.