demand for treatments and supplies that may not have been adequately stockpiled. If such health problems arise in combination with a disruption of supply chains for critical inoculations or medications, the potential for a severe health crisis could grow dramatically. Again, the effects might be felt far from the locations where the climate events occur. Climate events, especially when they occur in clusters, can also stress the capacity of international disaster response and humanitarian relief systems and thus cause harm in places that are not directly affected by the events but that need international assistance for other reasons.

Such shocks to integrated global social, economic, health, or technological systems are likely to have different effects in different places. It is reasonable to expect that they would be most disruptive in countries that are dependent on imports of the products of the global system that is shocked and in places or among populations that are particularly susceptible to harm if the availability of the outputs of those systems is restricted by price or policy.

EXPOSURES

Since the 1980s the number of recorded natural disasters related to weather and climate events has roughly doubled, while the number of those related to geophysical events, such as earthquakes, tsunamis, and volcanic eruptions, has neither increased nor decreased (Munich Re, 2012). Reported losses from global weather- and climate-related disasters also increased over the past few decades, mainly because of monetized direct damages to assets, with the amounts of losses varying greatly from year to year and region to region (Intergovernmental Panel on Climate Change, 2012). Since 1980 annual disaster losses have ranged from a few billion dollars to more than $200 billion (in 2010 U.S. dollars), with the greatest losses coming in 2005, the year of Hurricane Katrina. Loss estimates are lower bounds because many impacts, including the loss of human lives, cultural heritage, and ecosystem services, are difficult to monetize and so are poorly reflected in these estimates. Middle-income countries with rapidly expanding asset bases are particularly vulnerable to changes in the frequency, intensity, geographic range, and duration of extreme events. From 2001 to 2006 disaster losses were about 1 percent of gross domestic product (GDP) for middle-income countries, 0.3 percent of GDP for low-income countries, and less than 0.1 percent of GDP for high-income countries (Intergovernmental Panel on Climate Change, 2012). Most fatalities from extreme weather and climate events (95 percent) occur in developing countries.

The major causes of the long-term increase in economic losses from weather- and climate-related disasters have been the increasing exposure of people and the increased value of economic assets in exposed regions. Cal-



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