The Next Global Synthesis of Natural Hazard Risks: Observational and Data Management Needs

Arthur Lerner-Lam 1

Robert S. Chen 2

1Lamont-Doherty Earth Observatory

1,2Center for Hazards and Risk Research

2Center for International Earth Science Information Network

1,2The Earth Institute at Columbia University

Two recent reports by the World Bank and the United Nations quantify the global exposure of populations and economic activity to natural hazards. For example, the World Bank/Columbia University disaster risk “Hotspots “study estimates risk levels by combining hazard exposure with historical vulnerability for two indicators of elements at risk—gridded population and Gross Domestic Product (GDP) per unit area — for six major natural hazards: earthquakes, volcanoes, landslides, floods, drought, and cyclones. (Earthquake risks are incorporated using a formulation based on the GSHAP studies.) Calculating relative risks for each grid cell rather than for countries as a whole provides estimates of risk levels at sub-national scales. These can then be used to estimate aggregate relative multiple hazard risk at regional and national scales. The UN’s Disaster Risk Index study achieves essentially the same result. By casting mortality and economic loss in geographic terms, both studies have provided baseline arguments for linking disaster losses to other factors inhibiting economic growth, and for linking hazard mitigation to strategies for sustainable development.

However, the global analysis undertaken in these projects is limited by the availability and quality of geophysical and socio-economic data. For some hazards, there exist only 15- to 25-year global records with relatively crude spatial information. Data on historical disaster losses, and particularly on economic losses, are also limited. On one hand, the data are adequate for general identification of areas of the globe that are at relatively higher single- or multiple-hazard risk than other areas. On the other hand, they are inadequate for understanding the absolute levels of risk posed by any specific hazard or combination of hazards. Nevertheless it is possible to assess in general terms the exposure and potential magnitude of losses to people and their assets in these areas. Such information, although not ideal, can still be very useful for informing a range of disaster prevention and preparedness measures, including prioritization of resources, targeting of more localized and detailed risk assessments, implementation of risk-based disaster management and emergency response strategies, and development of long-term plans for poverty reduction and economic development.

A new global natural hazard synthesis, the Global Risk Identification Programme, will merge higher-resolution, region-specific risk assessments according to standards for data quality and analytical methodology. This paper will discuss this process and make suggestions for data acquisition and management, and geophysical monitoring.