Abstract: The interrelationships and interdependencies between humans and their environment are inherently complex and dynamic. Urban settlements are of particular complexity and interest because of their concentrated geographies, form and structure, material flows and cultural and population dynamics. The risk of climate change impacts imposes another level of complexity on such human environment systems and being able to better understand such complexity is becoming more urgent. This paper describes the methodological approach and conceptual framework developed for the Integrated Assessment of Climate Change Impacts on Urban Settlements (IACCIUS) project, which the author hopes will enable a better understanding. The methodology incorporates a number of approaches that lend themselves to the analysis of complex, dynamic, multi-scale, cross-sectoral, long-term real world problems posed by climate change. In particular, it describes how key aspects of dynamical systems thinking, urban studies; risk, vulnerability, adaptive capacity and uncertainty approaches; climate science; policy processes; demography and geography; stakeholder participation; and reflexive and iterative practice are incorporated into an IACCIUS conceptual framework. This paper concludes with a brief presentation of the evolving conceptual framework.