Let’s compare the del 13 carbon isotope data, after removing the seasonal cycle with the same technique, shown in Figure 5.
This is an amazing chart! There are two surprises immediately apparent in the del 13 chart, in comparison to the bulk CO2 chart. First, there is a wide separation between the curves on the del 13 chart, whereas the bulk CO2 curves are in a narrow band. Second, the del 13 chart shows large waves moving through the data, whereas the bulk CO2 curves are smooth and nearly linear. Let’s explore these two differences.
Atmospheric CO2 Carbon Isotope Data: