Infrastructural measures alone are seldom effective in building urban resilience as seen in the examples of the 2011 floods in Bangkok and the 2005 typhoon in Manila , or projected estimates by Pervin et al.  who found that structural interventions in existing drainage systems reduce flooding risk by 7-19% in Sylhet  and Bharatpur ; however, without proper solid waste management, areas under flood risk could increase to 18.5% in Sylhet and 7.6% in Bharatpur in five years, rendering the infrastructural interventions ineffective over time. While in some cities it is estimated that infrastructural adaptation through 'hard' flood protection strategies  is more effective than institutional or ecosystem-based adaptation by 2100, for example, Shanghai. A hybrid approach where hard strategies protect from flood risk, and soft strategies reduce residual risk from hard strategies, is suggested . In Japan, without adaptation, estimated damage costs of floods  by 2081-2100 under RCP2.6 will be 28% higher , rising to 57% higher under RCP8.5 . With a combination of adaptation measures , estimated damage costs can be reduced even below the 1981-2000 levels, and with a combination of mitigation and these adaptation measures, an estimated 69% reduction in flood damage costs are expected-demonstrating the importance of concerted and immediate climate action in reducing damage.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report