I have just watched a presentation by a paleoclimatologist by the name of Prof. Richard B. Alley, He also explains the role that CO2 has had over many millions of years of the earths climate history. He looks at all the controllers of climate, including the cosmic rays &c beloved of the skeptics.
There is a powerful graph showing a spike of cosmic rays that did not impact on the temperature record.
His conclusion - we can only explain the planet's climate by factoring CO2 in to the models. CO2 effect is key in making models match the observations. CO2 is the most important climate controller.
His review of the history of the subject shows how anomalies (gaps between theory and observations) are cleared up by more recent scientific work. The facts match the theory.
Anyone who is not fully convinced about man-made global warming should watch this.