There’s been quite a bit of discussion about CO2 data lately. Most of it has centered around Anthony Watts’ nonsense and the recent revision to the Mauna Loa monthly averages. What’s been lacking is a look at what the data are telling us about the changing CO2 concentration of the atmosphere. So let’s take a “quickie” look at monthly average CO2 data from three different locations: Mauna Loa, Barrow (Alaska), and South Pole station.