The first two parts of this series (Klevberg and Oard, 2011a, 2011b) introduced methods of studying past climate change, the historicity of the Medieval Warm Period and Little Ice Age, and the importance of the Little Ice Age in understanding climate change and constraining climatic models. The reasons for concentrating on the North Atlantic region include the richness of the historiography for the period and the utility of the geography in studying climatic constraints on the inferred postdiluvial ice age. Nowhere is the historiography richer or the geographic setting better for this than Iceland. This paper summarizes observations of climate change in Iceland from Landnám to the present and the contemporary glacial fluctuations.