Reduced insurable losses from heavy rain events after nature-based adaptation in Amsterdam

A new empirical study published in Natural Hazards and Earth System Sciences finds that municipal adaptation measures, such as green infrastructure and upgraded drainage, can substantially lower insured damages from intense short-duration rainfall (cloudbursts) in urban neighbourhoods. The research analyses insurance claims data across almost all Dutch insurers, focusing on a part of Amsterdam where adaptation measures were implemented, and compares it with a similar neighbourhood where no such measures were taken.

The authors from the Institute for Environmental Studies, Dutch Association of Insurers, and Deltares apply a difference-in-differences (DiD) approach, a quasi-experimental method that allows for causal inference. They compare a treatment area (where, between 2018 and 2022, the municipality implemented a suite of nature-based and other adaptation interventions) with a control area in the same district that did not receive such measures.

The results show that after implementation of the adaptation measures, insured rainfall damage per rain-day in the treatment area dropped by between €1,375 and €5,648, relative to the control area. The study also confirms that higher daily precipitation correlates strongly with higher insured damages, underscoring the climate-driven exposure to cloudbursts.

The authors conclude that combining green infrastructure (such as green streets, rain gardens, green roofs), enhanced water storage (on squares and under tram lanes), improved sewer systems and household-level rainproofing can effectively reduce insurance losses from pluvial floods. This provides strong empirical support for encouraging insurers, banks and municipalities to co-invest in adaptation measures as part of urban climate-resilience strategies.