Climate change impacts can be especially large in cities1, 2. Several large cities are taking climate change into account in long-term strategies3, 4, for which it is important to have information on the costs and benefits of adaptation5. Studies on climate change impacts in cities mostly focus on a limited set of countries and risks, for example sea-level rise, health and water resources6. Most of these studies are qualitative, except for the costs of sea-level rise in cities7, 8.