claim: "The IPCC’s Fourth Assessment Report, 2007, carries in three places a graph in which the Hadley Center’s global mean surface temperature anomaly dataset from 1850-2005 is displayed with four arbitrarily-chosen trend-lines overlaid upon it.
evidence: Some climate change denial groups say that because CO 2 is only a trace gas in the atmosphere (roughly 400ppm, or 0.04%, 4 parts per 10,000) it can only have a minor effect on the climate.