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Ryan Thomas

Ph.D. Candidate

Architecture, Art, and Planning Cornell University


Climate Risk Mapping in Contexts of Informality


Climate risk is spatialized within geographic information systems as the intersection of two layers—assets and hazard occurrence. In cities dominated by informal settle-ments, like Dar es Salaam, Tanzania, municipal databases lack the information needed for computer risk models, such as the location of assets (like schools and hospitals) and physical infrastructure, like roads and drainage. To begin addressing the lack of information, the World Bank developed a process called community mapping that re-lies on community engagement and mobile apps to rapidly collect data.

These efforts are also supported by open crowdsourcing infrastructure of Open-StreetMap and have led to the use of new tags and types of data being added to the platform. The social processes of data collection, along with the computer software they rely on, shape what risks are considered, and in turn, urban planning and policy making priorities focused on risk mitigation. This presentation reviews the emergence of the “community risk mapping” method as a method for spatializing flood risk and identifies the social and technological limitations of representing informal settlements on climate risk maps. I argue that flexible data standards offer both challenges and opportunities for just climate adaptation.



Ryan Thomas is a PhD candidate in City and Regional Planning at Cornell's Ithaca campus. His research examines the methods of producing metrics for policy and planning decisions, with a focus on spatial planning metrics in contexts of informality. His dissertation examines the political economy of climate change knowledge production in Dar es Salaam by exploring how NGOs, communities, the state, and international agencies to produce climate risk maps. Previously, Ryan worked on program evaluations for USAID, and contributed to a global index of urban environmental justice.

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