The Danger of Thermonuclear War
Andrei Sakharov is the distinguished Soviet physicist, winner of the 1975 Nobel Peace Prize, currently in internal exile in Gorki. Among his works available in English are Alarm and Hope and Collected Scientific Works. This article was written for publication in response to the materials noted, which had been sent to him by Professor Drell of Stanford. The translation from the Russian was done by Richard Lourie and Efrem Yankelevich. Copyright © Andrei Sakharov.
Dr. Drell's speech at Grace Cathedral (in San Francisco) is unpublished but available from him on request. His opening statement before the Subcommittee on Investigations and Oversight of the House Committee on Science and Technology is contained in the Committee's record of those hearings, The Consequences of Nuclear War on the Global Environment, September 15, 1982, p. 6. A more comprehensive statement of Dr. Drell's views will be found in his Danz Lectures, to be published by the University of Washington Press in June 1983 under the title Facing the Threat of Nuclear Weapons.
The Editor is grateful to Professor Drell and to Strobe Talbott for their help in refining the translation of technical terms, and in preparing the explanatory Editor's Notes, for which of course the Editor takes responsibility.
Andrei Sakharov
THE DANGER OF THERMONUCLEAR WAR
Dear Friend:
I have read your two splendid lectures—the speech on nuclear weapons at Grace Cathedral, October 23, 1982, and the opening statement to Hearings on the Consequences of Nuclear War before the Subcommittee on Investigations and Oversight. What you say and write about the appalling dangers of nuclear war is very close to my heart and has disturbed me profoundly for many years now. I decided to address an open letter to you, feeling it necessary to take part in the discussion of this problem, one of the most important facing mankind.
In full agreement with your general theses, I will express certain considerations of a more specific nature which, I think, need to be taken into account when making decisions. These considerations in part contradict some of your statements and in part supplement and, possibly, amplify them. It seems to me that my opinion communicated here in open discussion can prove of interest in view of my scientific, technological, and psychological experience, acquired in the period when I took part in work on thermonuclear weapons, and also because I am one of the few independent participants in this discussion in the U.S.S.R.
II
I fully agree with your assessment of the danger of nuclear war. In view of the critical importance of this thesis, I will dwell on it in some detail, perhaps repeating what is already well known.
Here, and later on, I use the terms "nuclear war" and "thermonuclear war" nearly interchangeably. Nuclear weapons mean atomic and thermonuclear weapons; conventional weapons mean any weapons with the exception of three types with the capability of mass destruction—nuclear, chemical, and bacteriological weapons.
A large nuclear war would be a calamity of indescribable proportions and absolutely unpredictable consequences, with the uncertainties tending toward the worse.
According to data from United Nations experts, by the end of 1980 the world's overall supply of nuclear weapons consisted of 50,000 nuclear charges.[1] The total power of these charges (most of which are in the 0.04- to 20-megaton range) amounts to 13,000 megatons according to the experts' estimates. The figures you have presented are not in conflict with those estimates. In this regard you mention that the total power of all the explosives used in the Second World War did not exceed six megatons (three megatons, according to the estimates with which I am familiar). However, when making this comparison one must take into account the greater relative efficacy of smaller charges with the same total power, but that does not alter the qualitative conclusions about the colossal destructive power of the nuclear weapons that have been amassed.
You also cite data according to which the U.S.S.R. at the present time (1982) has 8,000 thermonuclear charges deployed and the United States 9,000.[2] Many of these charges are warheads on ballistic missiles, and many of these are multiple independently-targetable reentry vehicles (MIRVS). It should be noted that the basis of the U.S.S.R.'s arsenal (70 percent, according to statements by smaller intermediate-range missiles, on mobile launchers. Eighty percent of the U.S. arsenal consists of submarine-based nuclear missiles, much smaller but less vulnerable than silo-based missiles, and also of strategic bombers carrying nuclear bombs, some of which are apparently very powerful. It is doubtful whether masses of aircraft could penetrate Soviet territory deeply—but a more precise assessment of their capabilities must take the possibilities of cruise missiles into account; these would probably be able to penetrate the enemy's air defense systems.
Currently, the most powerful American ICBMS (I am not speaking of the planned MX) possess several times less throw-weight than the principal land-based Soviet missiles.[3] The American ones carry fewer MIRVS, and the yield of their warheads is less. (It is assumed that when dividing the throw-weight of a missile among several warheads—let's say ten—the aggregate yield of the multiple warheads is less than the yield of a large single warhead on the same missile. But MIRVS greatly increase the ability of one side to attack compact targets on the other. MIRVS are also highly destructive against targets spread out over a wide area such as large cities. The aggregate yield may be less than that of a large single warhead, but the destructiveness will remain high because of the multiple blasts spread out over the area. I have dwelt on these details since they may prove of substance in further discussion.)
You cite the estimates of the international journal of the Royal Swedish Academy, according to which an attack on the principal cities of the Northern Hemisphere by 5,000 warheads with a total power of 2,000 megatons will kill 750 million people as a result of the shock wave alone.[4]
I would like to add the following to that estimate:
1. The overall number of long-range nuclear weapons possessed by the five nuclear powers is three or four times greater than the figure used in the Swedish estimate and their overall power is six to seven times greater. The accepted average number of casualties per missile—250,000 people—cannot be considered an overestimate if one compares the accepted average power of a thermonuclear charge of 400 kilotons with the power of the 17-kiloton explosion at Hiroshima and the number of victims from its shock waves, no fewer than 40,000.
2. An extremely important factor in the destructive capability of nuclear weapons is thermal radiation. The fires at Hiroshima were the cause of a significant portion (up to 50 percent) of the fatalities. With the increase of the charges' power, the relative role of thermal radiation increases. Therefore, this factor significantly increases the number of direct casualties.
3. During an attack on especially dense, compact enemy targets (like silo-based missile launchers, command points, communication centers, government institutions, shelters, and other of the more important targets) it must be assumed that a significant portion of the explosions will be ground-level or low. In such cases there inevitably will be "traces," bands of dust fallout raised by the explosion from the surface and "impregnated" by the products of uranium fission. Therefore, although the direct radioactive effect of a nuclear charge takes place in a zone where everything alive is, in any case, annihilated by the shock wave and by fire, its indirect effect—through fallout—proves very substantial. The area contaminated by fallout so that the total dose of radiation exceeds the safety limit of 300 roentgens is, for a typical one-megaton nuclear charge, thousands of square kilometers!
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