His views on climate change are set forth in a powerpoint presentation which has lots of graphs, but no references about where the graphs came from.
The first graph I looked at closely was on page 18 ("Measured Atmospheric CO2"), and was annotated to claim that measurements had been doctored by omitting data points that did not support the theory of global warming. I searched for the caption text ("The encircled values between...") and found a paper containing that graph: Global Warming - Global Winter - What sayeth the Data: Open Questions and New Theories by Klaus P. Heiss, an economist and mathematician who was director of the climate denialist organization Science & Environmental Policy Project. (Dr. Heiss also signed the Heartland Institute's Climate Change Reconsidered.)
The measurements being criticized are from a 1938 paper, The Artificial Production of Carbon Dioxide and its Influence on Temperature by Callendar, which is described as the first global warming paper. The criticism was raised in a 1955 paper, Has the amount of carbon dioxide in the atmosphere changed significantly since the beginning of the twentieth century? by Slocum. Callendar seems to have replied in a 1958 paper, On the amount of carbon dioxide in the atmosphere.
I hope that saves somebody some legwork! One of these days I'll write a bit more on this.