Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism

[摘要] We assess the potential damage and smoke production associated with thedetonation of small nuclear weapons in modern megacities. While the numberof nuclear warheads in the world has fallen by about a factor of three sinceits peak in 1986, the number of nuclear weapons states is increasing and thepotential exists for numerous regional nuclear arms races. Eight countriesare known to have nuclear weapons, 2 are constructing them, and anadditional 32 nations already have the fissile material needed to buildsubstantial arsenals of low-yield (Hiroshima-sized) explosives. Populationand economic activity worldwide are congregated to an increasing extent inmegacities, which might be targeted in a nuclear conflict. We find that lowyield weapons, which new nuclear powers are likely to construct, can produce100 times as many fatalities and 100 times as much smoke from fires perkt yield as previously estimated in analyses for full scale nuclear warsusing high-yield weapons, if the small weapons are targeted at city centers. A single "small" nucleardetonation in an urban center could lead to more fatalities, in some casesby orders of magnitude, than have occurred in the major historical conflictsof many countries. We analyze the likely outcome of a regional nuclearexchange involving 100 15-kt explosions (less than 0.1% of the explosiveyield of the current global nuclear arsenal). We find that such an exchangecould produce direct fatalities comparable to all of those worldwide inWorld War II, or to those once estimated for a "counterforce" nuclear warbetween the superpowers. Megacities exposed to atmospheric fallout oflong-lived radionuclides would likely be abandoned indefinitely, with severenational and international implications. Our analysis shows that smoke fromurban firestorms in a regional war would rise into the upper troposphere dueto pyro-convection. Robock et al. (2007) show that the smoke wouldsubsequently rise deep into the stratosphere due to atmospheric heating, andthen might induce significant climatic anomalies on global scales. We also anticipate substantial perturbations of globalozone. While there are many uncertainties in the predictions wemake here, the principal unknowns are the type and scale of conflict thatmight occur. The scope and severity of the hazards identified pose asignificant threat to the global community. They deserve careful analysis bygovernments worldwide advised by a broad section of the world scientificcommunity, as well as widespread public debate.

[学科分类] 大气科学