Here you go, it’s the secret of climate that we’ve searched for so long … SO … I can use that to calculate the climate sensitivity of the relationship. Just like the head post, I've used the log of the underlying data (to base 2, as in the head post). Only problem? The red line is not CO2. It’s the CPI, the U.S. Consumer Price Index, since 1850 … I hope you can see that this type of “match up the curves” is not all that diagnostic … w. PS: If you truly want to do this kind of analysis, you need to use a lagging equation on your forcings, and you need to include all known forcings. The problem is, most forcings we have no clue about for the 1800's … so we end up with error bars from floor to ceiling.