Climate change is widely understood as an environmental and economic threat, but new research from the University of Sydney shows it is also a growing social crisis, weakening the relationships people rely on to survive.

As the fifth anniversary of Hurricane Ida approaches later this summer, researchers across Penn show that flooding was not a statistical anomaly but the result of compounding forces—climate change, urbanization, and infrastructure—that are reshaping flood risk. By building a street-level model of the Schuylkill River, the team has identified a critical tipping point at which floods become uncontained, offering new insight into how urban rivers behave under extreme conditions.