Efficient Responses to Catastrophic Risk

The Indian Ocean tsunami of December 2004 has focused attention on a type of disaster to which policymakers pay too little attention-a disaster that has a very low or unknown probability of occurring but that if it does occur creates enormous losses. Great as the death toll, physical and emotional suffering of survivors, and property damage caused by the tsunami were, even greater losses could be inflicted by other disasters of low (but not negligible) or unknown probability. The asteroid that exploded above Siberia in 1908 with the force of a hydrogen bomb might have killed millions of people had it exploded above a major city. Yet that asteroid was only about two hundred feet in diameter, and a much larger one (among the thousands of dangerously large asteroids in orbits that intersect the earth's orbit) could strike the earth and cause the total extinction of the human race through a combination of shock waves, fire, tsunamis, and blockage of sunlight wherever it struck. Other catastrophic risks, besides earthquakes such as the one that caused the recent tsunami, include natural epidemics (the 1918-1919 Spanish influenza epidemic killed between twenty and forty million people), nuclear or biological attacks by terrorists, certain types of lab accidents (including one discussed later in this Article), and abrupt global warming. The probability of catastrophes resulting, whether or not intentionally, from human activity appears to be increasing because of the rapidity and direction of technological advances. It is natural to suppose that the prediction, assessment, prevention, and mitigation of catastrophes is the province of science, but in this Article, which is based on my book Catastrophe: Risk and Response, I will argue that economic analysis has an important role to play, as well.1 Able scientists can commit analytical errors when discussing policy that economists would easily avoid. Thus Barry Bloom, dean of the Harvard School of Public Health, has criticized the editors of leading scientific journals for having taken the position that "an editor may conclude that the potential harm of publication outweighs the potential societal benefits."2 (The specific reference is to publications from which terrorists could learn how to create lethal biological weapons.) Bloom calls this "a chilling example of the impact of terrorism on the freedom of inquiry and dissemination of knowledge that today challenges every research university."3 He appears to believe that freedom of scientific research should enjoy absolute priority over every other social value. Such a belief comes naturally to people who derive career advantages from being able to engage in a particular activity without hindrance, but this belief arbitrarily refuses to weigh costs and so consider the need to make tradeoffs. Bloom is particularly incensed at limitations on allowing foreigners to study science in American universities. Under the rubric of "Advancing Openness," he advocates changes in existing regulations to enable any foreigner who obtains a visa for studying science in the United States to pursue any area of scientific research, however sensitive and whatever the student's likely motive.4 Bloom's concern is understandable in terms of professional self-interest. American universities, and especially their graduate programs, are heavily dependent on foreigners. According to Bloom, 24 percent of the graduate students at Harvard are foreign.5 But professional self-interest is not a sure guide to sound public policy. I will begin my analysis of the catastrophic risk problem with the recent tsunami. Suppose that a tsunami as destructive as the one that struck the Indian Ocean occurs, on average, once a century and kills 250,000 people. That is an average of twenty-five hundred deaths per year. Even without attempting a sophisticated estimate of the value of life to the people exposed to the risk, one can say with some confidence that if an annual death toll of twenty-five hundred could be substantially reduced at a moderate cost, the investment would be worthwhile. …