Flood risk is projected to increase in humid areas in Asia and Africa and decrease in most regions of Europe except the UK and northern France by the end of this century, according to a new model published today in Nature Climate Change.
An international team of researchers, including Dr Dai Yamazaki from the University of Bristol, estimated the change in global flood risk in the 21st century with a state-of-the-art global hydrodynamics model that used the outputs from 11 global climate models under the latest climate change scenarios.
Dr Dai Yamazaki says, "So far, only a few studies have projected changes in floods on a global scale and none of these studies relied on multiple climate models. As the consistency of flood risk change among the 11 global climate models was found to be low in some regions, multi-model analysis for future flood risk assessment was needed."
In this study, the researchers used a global river routing model with an inundation scheme to compute river discharge and inundation area.
Their projections demonstrated a large increase in flood frequency in Southeast Asia, peninsular India, eastern Africa and the northern half of the Andes, with small uncertainty in the direction of change. In certain areas of the world, however, flood frequency was projected to decrease.
Dr Dai Yamazaki says, "We estimated the change in population exposed to flood by overlaying simulated flooded area onto global population data. Flood exposed population was projected to be increased significantly following global temperature rise. We also found a large inter-annual variability in flood risk. Adaptations to flood risk change should therefore be made before the increase trend in flood risk becomes significant."