Floods are important disturbances to urban socio‐eco‐technical systems and their meteorological drivers are projected to increase through the century due to global climate change. Urban flood models are numerical models that have the capability of representing the features of urban ecosystems and the mechanisms of flooding that impact them. They have the potential to play a critical role in flood risk assessment, operational response, and resilience planning, but existing models remain limited in their capability to represent integrated flooding processes in urban areas and provide the credible quantitative information needed to support risk assessment and resilience practice. Research to advance model development, facilitate intensive watershed monitoring for model parameterization and validation, and support collaboration between researchers and practitioners should be prioritized. This will represent a substantial, expensive effort, but will still be of great value as cities are faced with urgent challenges posed by climate change in coming decades.

Motivated by the need for cities to prepare for and adapt to climate change, we advance the paradigm of safe‐to‐fail by focusing on the decision dilemmas and the consideration of infrastructure failure consequences in developing infrastructure. Infrastructures are largely designed as fail‐safe; that is, they are not intended to fail, and when failure happens, the consequences are severe. Safe‐to‐fail has been recently presented as the antithesis of fail‐safe, without any specific guidance of what the paradigm is or how to apply it. There is an emerging need for stakeholders, including policy makers, planners, engineers, utilities, and communities to understand infrastructure failures, bring their knowledge into the infrastructure development process, and help adapt cities to unpredictable and changing climate risks. We frame safe‐to‐fail as an infrastructure development paradigm that internalizes the consequences of infrastructure failure in the development process. This framing of safe‐to‐fail further reveals an emerging “infrastructure trolley problem” where the adaptive capacity of some regions is improved at the expense of others. We demonstrate practical dilemmas in developing infrastructure under nonstationary climate and guide managing trade‐offs in the prioritization of different consequences of infrastructure failure.

Green stormwater infrastructure (GSI) is increasingly used to comply with stormwater management requirements under the Clean Water Act, but there is growing interest in leveraging GSI as part of climate change adaptation strategies. Success in contributing to this goal depends on what types of GSI are being used and how they are sized. Here we review GSI design storm requirements for the seven Urban Resilience to Extremes Sustainability Research Network (UREx SRN) cities in the United States. We find that while GSI in most of our study cities is designed for smaller, more common precipitation events (e.g., 1-year event) considered by current water quality regulations; GSI in several UREx cities is primarily focused on flood control and require design for much larger storms (e.g., 100-year events). In order for GSI to contribute to climate change adaptation, it is critical to ensure that design guidelines align with that goal.