The Economic Consequences of Disasters due to Asteroid and Comet Impacts, Small and Large

Abstract

The objective of this paper is to investigate the economic consequences of asteroid or comet impacts, referred to here as near Earth objects (NEO). As of September 8, 2005, according to the Near Earth Objects Program of NASA (NASA 2005), there are 3535 NEOs, of which asteroids (NEAs) are 3438. NEAs greater than 1 km in diameter are represented by 797. The number of potentially hazardous asteroids (PHAs) is 720, of which PHAs greater than 1 km are 146. Of these, 3 appear (on September 8, 2005) on the NASA “impact risk” page. An NEO that is less than 50 meters would have a 5 megaton energy impact, although NEOs of even less than 30 meters could be damaging, depending on their composition and density. From about 50 meters to about 1 km diameter, an impacting NEO can do tremendous damage on a local scale. With an energy level above a million megatons (diameter about 2 km), an impact will produce severe environmental damage on a global scale. Still larger impacts can cause mass extinctions, such as the one that ended the age of the dinosaurs 65 million years ago (15 km diameter and about 100 million megatons). Table 29.1, reproduced from Chapman (Chap. 7 of this volume) is instructive; it summarizes impact energies and possible physical damages.