This is an amazing visualization of the carbon dioxide concentration in the atmosphere from today to 800 000 years ago made by the U.S. National Oceanic and Atmospheric Administration (NOAA). The video is credited to Andy Jacobson, CIRES/NOAA.
The full video (3min 14s) shows direct measurements of CO2 in the atmosphere at more and more data points over the globe (1979-2011), then the Keeling data set from Mauna Loa (1958-1979), then finally CO2 concentrations in bubbles captured in ice cores drilled from the Antarctic ice sheets. In the first segment, note especially how the seasonal changes changes the CO2 concentrations more in of the northern hemisphere than in Antarctica (compare the red and blue dots). This is simply a brilliant visualization of a massive amount of research over more than half a century.
The HD-video (.mp4) can be downloaded here (e.g. for use in presentations): http://www.esrl.noaa.gov/gmd/ccgg/trends/history.html
The same short video is included in this NOAA clip, with a narrative by Dr. James Butler, NOAA: