Time’s Bitter Flood: Trends in the number of reported natural disasters

Publication date

27 May 2011

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This report analyses the number of reported disasters in those regions where the majority of the world’s poor and vulnerable people live: sub-Saharan Africa, South and South-East Asia, and Latin America and the Caribbean. It presents analysis of the trends in the number of reported disasters, assesses what country-level factors influence the reported number of disasters, and compares the findings with independent published studies. There is an upwards trend in the number of reported disasters. This is chiefly driven by a steep rise in reported floods in all regions and, to a lesser extent, storms in Africa and the Americas. When weather-related disasters are analysed separately, the average rate of increase is 4.1 per cent per year for the sample of countries which have a first disaster reported from 1980 (a rise of 233 per cent over 30 years), and 4.9 per cent per year for countries whose first report was from 1990 or before (159 per cent over 20 years). An increase in the number of people exposed to disasters (approximated by population growth) partly explains the trend, but not fully. It is unlikely that reporting bias fully explains the trend either. Although it was not possible to estimate directly, it is therefore possible that an increase in the number of hazards is responsible for some of the increase in reported disasters, even if only a small part. This is consistent with the reported increase in extreme weather events across many parts of the world.