Possibilities and challenges in the development of a global flood disaster risk indicator from the post-2015 UN processes perspective: a preliminary study

This study aims to contemplate possibilities and challenges in the current development of global flood disaster risk indicators (GFDRIs). To this end, methodological requirements are first identified from stakeholders' opinions included in the post-2015 UN Development process and the post-2015 Hyogo Framework for Actions process. Then, state-of-the-art methods are applied, as a preliminary attempt, to fourteen countries in Asia to understand how the GFDRI estimates plausibly describe the number of affected people and fatalities under the 50-year return period condition. The results show that GFDRIs are capable of overcoming the unavailability of data necessary to analyze flood inundation depths and areas, describing the number of people affected by flood events, using vulnerability proxies contextually meaningful to understand why flood fatalities disproportionally occur in less developed countries, and making GFDRIs simple, understandable and transparent estimates. Simultaneously, it is revealed that there is still much room to technically improve GFDRIs, especially in dealing with reluctance in assigning a single value to an indicator for a large area such as a country, inaccessibility to authorized disaster records, difficulties in showing the effectiveness of infrastructure such as dams and dykes, and lack of local knowledge about vulnerability.