Drought as a Natural Hazard: Concepts and Definitions

Introduction Worldwide, economic damages attributed to natural disasters tripled from the 1960s The economic, social, and environmental costs and losses associated with drought are also increasing dramatically, although it is difficult to quantify this trend precisely because of the lack of reliable historical estimates of losses. White and Haas estimated in 1975 that the average annual crop losses associated with drought in the Great Plains region of the United States were about US$700 million. In 1995, the US Federal Emergency Management Agency (FEMA) estimated annual losses attributable to drought at US$6-8 billion (FEMA 1995). More specific figures from recent drought episodes in the United States provide a clearer picture of the magnitude of drought losses and our continuing vulnerability. The southwestern and southern Great Plains states experienced dramatic impacts on agriculture , water supply, wildfires, transportation, and tourism and The estimated losses further illustrate the trend in vulnerability in the United States. Factors that may explain this trend are numerous; they include deficiencies in monitoring and early warning systems and the application of this information by decision makers, urbanization, population growth and regional population shifts to more drought-prone areas, outdated or inappropriate water management policies and practices, lack of contingency planning, fragmented responsibilities in water/drought management by government agencies, and poor coordination within and between levels of government. Thus, vulnerability is increasing in the United States despite dramatic technological advances and the availability of large financial resources (Riebsame et al. 1991). The series of drought years that occurred in the United States between 1986 and 1992, as well as severe drought conditions that prevailed in 1994, 1996, and 1998, has further reinforced the reality of the nation's vulnerability. What concerns many scientists and decision makers is the diversity and complexity of drought impacts and the low level of preparedness for future events. The ongoing debate about climate change and its potential effects on the frequency and severity of extreme climatic events is adding further to the concerns of scientists and decision makers. The concerns about the trends in losses associated with natural disasters in developed countries are magnified when placed in the context of developing nations. Natural hazards result in significant loss of life and serious economic, environmental, and social impacts that greatly retard the development process. Figure 1.1 illustrates the trend of major natural disasters between 1963 and 1992, expressed as the number of disasters affecting 1 percent or …