Abstract: This dissertation examines scientific uncertainty as a boundary-ordering device between natural and social scientists. While current research in the human dimensions of global climate change typically uses knowledge and certainty as predictors of an individual's position on global climate change, then collapses the differences between scientists of different expertise into one expert group assumed to be both knowledgeable and certain on global climate change and then compares expert and non-expert beliefs in global climate change, this dissertation took a different approach. This research compares scientists of different expertise and focuses on how natural and social scientists differ in their assessments of the philosophic roots of uncertainty relating to global climate change. In particular, it explores whether the disagreements of natural and social scientists are related to their assessments of the philosophic roots of uncertainty of global climate change communicated during interdisciplinary discussions. As such the present study sought a methodological approach for data collection -- Sense-Making -- that could successfully discern differences in how natural and social scientists conceptualize and communicate uncertainty and how these conceptual differences relate to their perceptions of global climate change. Results revealed differences in natural and social scientists2 perceived source of disagreement, assessments of the philosophical nature of uncertainty and the types of bridging strategies suggested. Additionally, with 2 significant main effects and 14 significant interactions, assessment of the philosophic roots of uncertainty appears to be a mediating variable in the relationship between level of knowledge or sureness and the belief that global climate change is occurring or perceived risk global climate change poses to humans between natural and social scientists. These findings suggest scientific uncertainty is a boundary-ordering device not only between experts and non-experts, but also between natural and social scientists. Moreover, it suggests that the current expert-non-expert model of belief in global climate change may be insufficient to explain the complex dialogic and decision-making environment. Finally, that Sense-Making is a methodology that can acknowledge interdisciplinary differences in the communication of uncertainty between scientists of different expertise and provide a way to view and compare these differences empirically.