Urban flooding risks are also increased by urban expansion and land use and land cover change which enlarges impermeable surface areas through soil sealing, impacting drainage of floodwaters with consequent sewer overflows  . These risks are also driven by increasing societal complexity, urban developmental policy on flood control and long-term economic growth , including in mega-cities . The increase in flood risk from urban development can be considerable; based on modelling of two RCP  scenarios, Kaspersen et al.  noted flooding in four European cities could increase by up to 10% for every 1% increase in impervious surface area. Risks are also compounded by the location of settlements, with greater risks within cities located in low elevation coastal zones subject to sea level rise, potential land subsidence and exposure to tropical cyclones  and within informal settlements, where generally little investment in drainage solutions exists and flooding regularly disrupts livelihoods and disproportionately undermines local food safety and security for the urban poor .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report