The amount of CO2 in the air can be measured. The National Oceanic and Atmospheric Administration (NOAA) department has been collecting data on the amount of CO2 in the air since the early 1950s. The data we'll be using can be found at https://www.esrl.noaa.gov/gmd/ccgg/trends/data.html. We'll specifically be using that Mauna Loa monthly mean data.
The data, after removing the comments, looks something like this:
# decimal average interpolated trend #days# date (season corr)1958 3 1958.208 315.71 315.71 314.62 -11958 4 1958.292 317.45 317.45 315.29 -11958 5 1958.375 317.50 317.50 314.71 -11958 6 1958.458 -99.99 317.10 314.85 -11958 7 1958.542 315.86 315.86 314.98 -11958 8 1958.625 314.93 314.93 315.94 -1
In particular, ...
