Graphical measurements of rising carbon dioxide

keeling curve graphic
Figure 1 is the "Keeling curve". It measures atmospheric buildup of carbon dioxide. The amount drops each summer as plants suck up more carbon dioxide but then increases once leaves are shed each Fall.

rising carbon dioxide picture
Figure 2 is ice core data showing CO2 levels over this millennium.

For more, see Greenhouse: The 200-Year Story of Global Warming.