Assessment of Long-Term Flood Risk Change in Japan

Flood disasters are among the most pressing global challenges, posing serious threats to sustainable development. As countries and regions experience flood risks of varying degree and origin, the need for improved information sharing has become both critical and urgent, particularly under the accelerating impacts of climate change. Over the past several decades, Japan has undergone substantial changes in flood risk driven by climatic, hydrological, socioeconomic, and demographic factors. This work investigates long-term trends in flood risk in Japan by examining changes in hazard, exposure, and vulnerability. The results show that climate change has intensified both flood hazards and exposure, while aging in both population and infrastructure has increased societal vulnerability. While flood risk has been widely studied, this research advances existing knowledge by offering new insights into the long-term assessment of flood risk.