Making Sense of Recent Calamities

INTRODUCTION A disaster happens when an extreme event occurs in the context of societal vulnerability. Nowhere is the meeting of vulnerability and extreme more tangible than where the land meets the sea. This was horrifi cally apparent on 26 December 2004 when a powerful earthquake under the eastern Indian Ocean caused a massive tsunami that killed more than 280,000 people and caused billions of dollars (all dollars in this article refer to U.S. dollars) in damage. Other disasters at the ocean-land boundary are similarly fresh in our minds—the U.S. hurricane seasons of 2004 and 2005 resulted in hundreds of billions of dollars in damage and more deaths than in the previous 35 years combined. We do not have to look too far back in time to recall other tragedies, such as Hurricane Jeanne, which killed several thousand people in Haiti in 2004; the Venezuelan coastal landslides in 1999, which killed upwards of 30,000 people; and Hurricane Mitch in 1998, which killed more than 10,000 people, mainly in Nicaragua and Honduras (Taft, 2004; Pielke et al., 2003). In 1991, perhaps 150,000 people died in Bangladesh as the result of storm surge and fl ooding from a tropical cyclone (Pielke and Pielke, 1997). The recent spate of disasters has created two common perceptions among decision-makers and the general public. First, there is a sense that the economic impacts associated with extreme events have increased in recent years. Second, given that a human infl uence on the climate system has been well established, a perception exists that the recent increase in weather-related disasters like fl oods and hurricanes is in some way related to changes in climate. These perceptions beg two questions: • Have loss of life and damages associated with extreme weather events actually increased in recent years? • What factors account for observed trends in the impacts of weather on society? The answers to these questions are more than simply idle speculations—they help shape how we think about policy options with important social, economic, and political ramifi cations (such as disaster preparation, insurance, international climate-change negotiations) and how we set priorities for the funding of scientifi c research. Because policy is based in part on the perceptions that policy-makers hold about weather and climate, it is worth determining the answers to the two questions in a scientifi cally rigorous manner. This lecture discusses trends B Y R O G E R A . P I E L K E , J R . S E V E N T H A N N U A L R O G E R R E V E L L E C O M M E M O R AT I V E L E C T U R E