PNAS: The Ecology of Segregation in Cities

This issue of PNAS (Vol. 123, No. 38; September 2026) prominently features a special section on the "Ecology of Segregation in Cities," presenting research and perspectives on how historic residential segregation, redlining, and gentrification structurally impact modern urban ecosystems, climate resilience, biodiversity data availability, and environmental health disparities. This issue also includes a newly featured study by several Urban Systems Lab member in Iwaniec et al., “Insights from co-produced scenarios toward urban sustainability transformations.” Emerging from the NSF-funded UREx SRN network and co-led by the Urban Systems Lab, the paper analyzes 60 positive future visions across nine U.S. and Latin American cities to show how systemic urban resilience requires connected changes across institutions, power dynamics, and values.