World’s population susceptible to water risks is concentrated in two of the 58 IPCC reference regions

This study shows how the global population exposed to water-related risks is disproportionately contained in two reference regions and reflects on the implications for future Intergovernmental Panel on Climate Change (IPCC) assessments. In assessing future climate change risks the IPCC makes use of 58 standardized geographical reference regions. Global human population numbers and water-related risks in terms of economic and non-economic loss and damage are unevenly distributed across these reference regions.

The analysis suggests that the geographical reference regions being used by the IPCC would benefit from further spatial disaggregation in highly populated parts of the planet, especially South and East Asia. Current geographical boundaries being used are suitable for climate hazard identification as is done by IPCC Working Group I but are too coarse spatially when climate change impacts are viewed from a population-at-risk perspective as is done in Working Group II. With loss and damage becoming a growing preoccupation of the United Nations Framework Convention on Climate Change (UNFCCC) process, authors suspect policymakers will increasingly turn to the IPCC and particularly researchers whose work contributes to Working Group II assessments to generate projections of where future loss and damage potential is greatest. They suggest that reconsideration of the number of geographical reference regions in heavily populated regions and their boundaries is warranted. Having a larger number of geographical reference units with higher spatial resolution for heavily populated parts of the world would also support more detailed risk assessments in future Working Group II regional chapters, with particular relevance to Asia.