An Empirical Orthogonal Teleconnection (EOT) analysis of the AIRS CO2 product (monthly anomalies from 2003-2008) using the Earth Trends Modeler (ETM) very clearly shows the progressive increase in CO2 in the mid-troposphere. Below we see the EOT correlation image and its associated temporal graph.
All areas of the globe show very high correlations with the trend, although they are lower in the boreal and tropical forests. Note that this analysis is based on anomalies so that the seasonal variation inherent in the Keeling curve is not so evident.
An analysis of the Theil-Sen slope (below) of the same series shows the rate of increase. Here we see a clearly lower rate of increase in the tropics with the highest rate in Siberia.