Among many potential causes for policymakers' contention over whether there is a largely unified scientific agreement on global warming and climate change (GWCC), one possible factor, according to the information deficit theory, is that the scientists who testified in congressional hearings might be substantially divided in their views and positions associated with GWCC. To clarify this, we perform content analysis of 1350 testimonies from congressional GWCC hearings over a period of 39 years from 1969 to 2007 and use the data derived from this content analysis to provide an overview of scientist witnesses' stances on GWCC. The key findings include: (1) among the scientists' testimonies with an expressed view on whether GWCC is real, a vast majority (86 %) indicates that it is happening; (2) among the scientists' testimonies with an identified stance on whether GWCC is anthropogenic, a great majority of them (78 %) indicates that GWCC is caused, at least to some degree, by human activity; (3) even under Republican controlled congresses, there is still a supermajority (75 %) - among the scientists' testimonies with an expressed position on GWCC existence or GWCC cause - that believes that GWCC is real and that GWCC is anthropogenic; (4) most scientists' testimonies (95 %) endorse pro-action policy to combat GWCC; and (5) the percentages of scientists' views and positions are consistent across different types of scientist testimony groups. Our findings suggest that the scientific information transmitted to Congress is not substantially different from the general agreement in the climate science community.
