Natural disasters

Numbers of great natural disasters per year, 1950-2001

Graph shows increasing trend in frequency of 'great' natural disasters. Catastrophes are classed as great if the ability of the region to help itself is overtaxed, making inter-regional or international assistance necessary, as is usually the case when thousands of people are killed, hundreds of thousands made homeless or when a country suffers substantial economic losses Source: Munich Re 2001

People and the environment are increasingly suffering from the effects of natural disasters. There are a number of reasons for this such as high population growth and density, migration and unplanned urbanization, environmental degradation and possibly global climate change. The sheer scope of the socioeconomic impacts of natural disasters has brought about a shift in the political approach to dealing with the concept of risk in modern societies.

Comparing the past two decades, the number of people killed in natural and non-natural disasters was higher in the 1980s (86 328 annually) than in the 1990s (75 252 annually). However, more people were affected by disasters in the 1990s - up from an average of 147 million a year in the 1980s to 211 million people a year in the 1990s. While the number of geophysical disasters has remained fairly steady, the number of hydrometeorological disasters (those caused by water and weather) has increased (see figure). In the 1990s, more than 90 per cent of those killed in natural disasters lost their lives in hydrometeorological events such as droughts, windstorms and floods. While floods accounted for more than two-thirds of people affected by natural disasters, they are less deadly than many other types of disaster, accounting for only 15 per cent of deaths (IFRC 2001).

The social and economic costs of disasters vary widely and are difficult to estimate on a global basis. Insurance claims tend to be misleading as an estimate of the economic impact of disasters. Considering insured damage claims for the 1999 floods in Austria, Germany and Switzerland, at least 42.5 per cent of damage was covered by disaster insurance. But in Venezuela the same year, only 4 per cent of flood damage was covered (CRED-OFDA 2002). There is a need for reliable and systematic data on disasters to help assess their socio-economic and environmental impacts in both the short and the long term. But although communities in developing countries suffer from numerous local-scale disasters such as wildfires, small floods, droughts and pest infestations, these are often not reflected in disaster statistics.

Economic costs of great natural disasters (US$billion), 1950-2000

In comparison with the 1960s, economic losses during the 1990s increased by a factor of almost nine Note: chart shows only the cost of 'great' natural catastrophes - see figure above for definition Source: Munich Re 2001

The most expensive disasters in purely financial and economic terms are floods, earthquakes and windstorms but events such as drought and famine can be more devastating in human terms. While earthquakes accounted for 30 per cent of estimated damage, they caused just 9 per cent of all fatalities due to natural disasters. In contrast, famine killed 42 per cent, but accounted for just 4 per cent of damage over the past decade (IFRC 2001). In 1999, global financial losses from natural catastrophic events were estimated to exceed US$100 billion - the second highest figure on record. A total of 707 large events were recorded compared to 530 to 600 events in previous years. It is even more striking that the number of major catastrophic events over the past decade has increased threefold in comparison with the 1960s, while the rate of economic losses has increased by a factor of almost nine over the same period (Munich Re 2001).

Between 1995 and 1997, the impacts of natural hazards cost the United States at least US$50 billion a year, or the equivalent of about US$1 billion a week (IDNDR 1999a). The economic losses of the United States because of the 1997-98 El Niño event were estimated at US$1.96 billion or 0.03 per cent of GDP. Ecuador suffered equivalent financial losses but this represented 11.4 per cent of its GDP. The floods in China in 1991, 1994-95 and 1998 caused losses ranging from US$20 to 35 billion (CNC-IDNDR 1999). The annual loss from natural disasters over the period from 1989 to 1996 is estimated to range from 3 to 6 per cent of China's GDP, averaging 3.9 per cent. In December 1999, the Anatol, Lothar and Martin storms generated losses in northern Europe amounting to US$5-6 billion (Munich Re 2001). Less developed countries with limited economic diversity and poor infrastructure must not only rely mostly on external relief if a disaster happens but their economies need more time to recover. In developed economies, governments, communities and individuals have greater capacities to cope with disasters, the economic losses are to some extent absorbed by a diversified economy, and most assets are insured.

Among the least developed countries, 24 of the 49 face high levels of disaster risk; at least six of them have been affected by between two and eight major disasters per year in the past 15 years, with long-term consequences for human development (UNDP 2001). Since 1991, more than half of all the disasters reported occurred in countries with medium levels of human development (see 'Socio-economic background'). However, two-thirds of those killed came from countries with low levels of human development, while just 2 per cent came from highly developed countries. The effect of development on disasters is dramatic: on average, 22.5 people die per reported disaster in highly developed countries, 145 die per disaster in countries with medium human development, and 1 052 people die per disaster in countries with low levels of development (IFRC 2001).

A number of experts link the current trend in extreme weather events with an increase of the global mean temperature. Many parts of the world have suffered major heat waves, floods, droughts and other extreme weather events. While individual events, such as El Niño-related phenomena (see box below), cannot be directly linked to human-induced climate change, the frequency and magnitude of these types of events are predicted to increase in a warmer world. The changes in the global mean temperature are 'very likely' to affect parameters such as precipitation patterns, wind velocities, soil moisture and vegetation cover which appear to influence the occurrence of storms, hurricanes, floods, drought and landslides (IPCC 2001). For example, the extent of damage from storm surges can be directly linked to sea level variations.

Climate change and variability alone do not explain the increase in the impacts related to disasters. 'Natural' can be a misleading description for disasters such as the droughts, floods and cyclones which afflict much of the developing world. Identifying humaninduced root causes, and advocating structural and political changes to combat them, is long overdue (IFRC 2001). For example, destruction of the natural environment because of logging or inappropriate land uses for short-term economic gain is one of the major factors promoting floods or mudslides such as those that hit Venezuela in December 1999. Similarly, the migration of population to urban and coastal areas increases human vulnerability as population densities increase, infrastructure becomes overloaded, living areas move closer to potentially dangerous industries, and more settlements are built in fragile areas such floodplains or areas prone to landslides. As a result, natural catastrophes affect more people and economic losses are increased. For example, despite the fact that seismic activity has remained constant over recent years, the effects of earthquakes on the urban population appear to be increasing.