Sr⁹⁰ in the soil—measured in thousandths of a gram per square mile.
Sr⁹⁰ in the soil—measured in thousandths of a gram per square mile.
Average Sr⁹⁰ in U.S. milk—measured in trillionths of a gram per quart.
Average Sr⁹⁰ in U.S. milk—measured in trillionths of a gram per quart.
Average radiation doses from Sr⁹⁰ in bones of young children (U.S.)—measured in roentgens per year.
Average radiation doses from Sr⁹⁰ in bones of young children (U.S.)—measured in roentgens per year.
The actual amounts of Sr⁹⁰ in the soil, in the milk, and in the bones of young children are only approximately known. But the main point that we are trying to illustrate, is that since 1954 the buildup of Sr⁹⁰ has gone on at a rather steady rate. How far will this buildup continue?
More radioactivity was released in tests in the year 1954 than in all other years put together. Probably more than one-half of that activity has already been deposited. Since that time the fission energy produced in U.S. tests has steadily decreased. Furthermore, we have learned how to minimize the world-wide fallout by employing ground bursts which deposit most of their activity in the close-in fallout near the test site. It is also possible to place chemical additives near the bomb in order to convert the strontium into a more insoluble form or else into a form which will more readily fall out in the immediate neighborhood of the explosion. And what is most important—we are developing clean nuclear weapons, which produce blast and heat but greatly reduced radioactivity. In the future these clean weapons may eliminate the additional radioactivity altogether.
It is hard to make predictions about the plans of all nations. If we find—and others also find—that clean weapons are the most desirable, the total strontium contamination is not likely to become more than perhaps two to four times the present value. We believe that all reasons—respect for human life, military considerations and simple sanity—lead to one conclusion. In the development of nuclear explosives we must endeavor to make them clean. But the real reason for this does not lie in the small contamination due to tests. The real reason is that war could turn contamination into a danger to countless people.
How much harm is being done by the atomic tests? Some scientists have claimed that from past tests alone about 50,000 persons throughout the world will die prematurely. There is no general agreement on this point. Some think the number should be smaller. It is possible that radioactivity produces some effects which prolong life rather than shorten it. But even if all the biological consequences of radiation were known many questions would still demand answers. Can tests be justified if they actually shorten some human lives? Even the possibility of a health hazard must be taken most seriously. On the other hand: Are there any reasons which make continued testing necessary?
We shall return to these questions in a later chapter. First, however, we shall try to put before the reader the known facts about the fallout danger to the individual. We shall try to put this danger into perspective by relating it to other more familiar dangers to which all of us are exposed. In the following chapter we shall discuss how the fallout may affect future generations.
The dangers from big doses of radiation are well known.Exposure to a thousand roentgens over our whole body causes almost certain death in less than thirty days. Four or five hundred roentgens give a fifty-fifty chance of survival. At less than a hundred roentgens, there is no danger of immediate death. Three years ago the Marshallese got a dose of 175 roentgens. None died. Apparently all are in good health.
Over longer periods of time even bigger radiation doses can be tolerated. A thousand roentgens spread over a lifetime produce no apparent biological consequences in individual cases. A rough rule (which is not too well-established) is that five times as much radiation can be tolerated if one is exposed to only a little radiation at any one time.
A hundred roentgens all at once, or several times this amount over a protracted time period, will not cause sickness or death that can be directly blamed on the radiation. However, such a dose of radiation may have harmful biological consequences which are more subtle. An exposed individual may develop an increased susceptibility to certain diseases, notably bone cancer and leukemia. Leukemia is a fatal disease in which the white blood cells multiply too rapidly.
A person who receives a hundred roentgens does not necessarily contract bone cancer or leukemia. Rather, his chance of contracting these diseases during his lifetime may have been increased. Knowledge of this kind can be obtained only with the help of statistics.
If, for example, a large number of mice receive a heavy dosage of radiation over a long period of time, one finds that the incidence of tumors and leukemia is higher amongst such irradiated animals than the natural incidence of these diseases.
Direct evidence with human beings—fortunately—is rather scarce. Statistics exist on the survivors of Hiroshima and Nagasaki, and also on radiologists. The latter group probably receive several hundred roentgens during their professional lifetimes. In addition, some statistics exist on children whohave been treated with large doses of radiation for enlarged thymuses. Persons suffering from ankylosing spondylitis, which is a painful disease of the spinal joints, have also been treated with large X-ray doses. The statistics in all these cases lead to the same conclusion: that large doses of radiation increase the likelihood that an individual’s life will be shortened by leukemia and possibly also other cancers. Furthermore, it appears (mainly from the experiments on animals) that the increased likelihood is simply proportional to the amount of radiation received, at least for doses in the neighborhood of several hundred roentgens or so.
This of course sounds frightening. But the radiation doses from the world-wide fallout are in a completely different class from those we have been discussing. They are very much smaller. On the average human bones are getting about 0.002 roentgens per year from the Sr⁹⁰ in the fallout. In addition the whole body is receiving a roughly equal amount in gamma rays, mainly from Cs¹³⁷. These figures apply to new bone in young children who have grown up in an environment of Sr⁹⁰ in the northern part of the United States. This is a region of maximum fallout. Adults whose bones were made for the most part before the atomic testing started are getting about 0.0003 roentgens per year from Sr⁹⁰. None of these figures appears to be alarming.
At this present rate a lifetime dosage in northern U.S. is only a small fraction of a roentgen. A rare individual might get several times this amount. If tests continue at the present rate, radiation levels could increase by as much as five-fold. However, even in this situation it is difficult to imagine anyone receiving a lifetime dose of more than five or ten roentgens from the world-wide fallout. A more reasonable estimate for the average lifetime dose would be a few roentgens or less.
One might conclude from these figures that there is no danger whatsoever from the fallout. This conclusion, however, may not be correct.
The danger from such small doses of radiation is not easy to define. Even the best statistical methods are insufficient. One is looking for small effects which show up only after millions of cases have been studied. Animal experiments are extremely difficult to carry out under these conditions. Direct controlled experience with human beings is, of course, impossible. As a result, one is forced to draw conclusions from the effects at higher dose levels, where experimental data have been obtained.
This may be done in many ways. One way is to assume that the law of proportionality holds down to the smallest doses. This means that one roentgen produces one hundredth as many cases of bone cancer and leukemia as 100 roentgens produce. This law is plausible. It is by no means proven.
By arguing in this way one finds that for each megaton of fission energy which escapes from the test site in the world-wide fallout the lives of approximately four hundred persons would be shortened by leukemia or bone cancer. Under present conditions of testing, roughly one half of the fission products are deposited as close-in fallout in and near the test site. Per megaton of fission energy exploded, therefore, perhaps 200 persons may get leukemia or bone cancer. This figure could actually be higher, possibly even a thousand persons or more per megaton. It could also be lower. It could be zero.
It is possible that radiation of less than a certain intensity does not cause bone cancer or leukemia at all. In the past small doses of radiation have often been regarded as beneficial. This was not supported by any scientific evidence. Today many well-informed people believe that radiation is harmful even in the smallest amounts. This statement has been repeated in an authoritative manner. Actually there can be little doubt that radiation hurts the individual cell. But a living being is a most complex thing. Damage to a small fraction of the cells might be beneficial to the whole organism.Some experiments on mice seem to show that exposure to a little radiation increases the life expectancy of the animals. Scientific truth is firm—when it is complete. The evidence of what a little radiation will do to a complex animal like a human being is in an early and uncertain state.
In any event the number of additional cases of leukemia and bone cancer due to the fallout radiation is certainly too small to be noticed against the natural incidence of these disorders.
In the next thirty years about 6,000,000 people throughout the world will die from leukemia and bone cancer. From past tests, which have involved the explosion of about fifty megatons of fission energy, the possibility exists that another 50 × 200, i.e., 10,000 cases may occur. Statistical methods are not able to find the difference between 6,000,000 and 6,010,000. There is no way to differentiate between the fallout-induced cases of leukemia and bone cancer, and those which occur naturally.
The possible shortening of ten thousand lives may seem rather ominous. But mere figures can be misleading. A better way to appreciate the danger from fallout is to compare it with other more familiar dangers. Such a comparison can be made with the natural background of cosmic rays and radioactivity in the earth and in our own bodies.
We are constantly and inescapably exposed to this radiation. Our ancestors have been exposed to it. The human race has evolved in such a radioactive environment. Moreover, the biological effects from different kinds of radiation can be compared in a meaningful way in terms of roentgens. Therefore the danger from Sr⁹⁰ is not unknown in every respect. In some ways it is very well-known because we and all living beings have spent our days in a similarly dangerous surrounding. We live on an earth which has radioactivity in its rocks, which carries a similar activity in its waters, and which is exposedfrom all sides, to a rain of particles which produce effects identical with the effects of radioactive materials.
Not all radiations which have the same intensity (the same number of roentgens) have precisely the same effect. The damage produced also depends somewhat on the spacing of the ionized and disrupted molecules. The cosmic rays and the Sr⁹⁰, however, are quite similar even in this respect.
The reader will recall that the spacing of the ionization depends only on the charge and the speed of the ionizing particle. The ionizing particle from the Sr⁹⁰ is an energetic beta ray, which has a charge of one and a speed close to that of light. A large part of the background radiation which reaches our bones comes from the cosmic rays. The main portion of the cosmic rays is due to the mesons. The meson, like the beta ray, has a unit charge and a speed close to that of light. The two particles may therefore be expected to produce identical biological effects. The only difference between their effects is that the beta ray does not have enough energy to leave the bones, while the meson is so energetic that it deposits its energy both in our bones and throughout our whole body. Thus if we compare a Sr⁹⁰ dose with the same dose of cosmic rays the same effect to the bones must be expected. But the cosmic rays give rise to additional effects in our bodies.
The total background dose to the bones is about 0.15 roentgens per year for the average person living at sea level in the United States. Of this amount, about 0.035 roentgens is due to cosmic rays. At higher altitudes the cosmic ray dosage increases. In Denver, at an altitude of 5000 feet, the cosmic rays contribute 0.05 roentgens per year.
The above numbers should be compared with the present level of world-wide fallout radiation to the bones: about 0.003 roentgens per year (from Sr⁹⁰ and other sources). The fallout radiation is thus only a few per cent of the natural cosmic radiation. It is small even when compared to the variationof cosmic ray intensity between sea level and 5000 feet.
A correlation between the frequency of leukemia and bone cancer, and the intensity of natural radiation has been looked for. Some statistics for the year 1947, before weapons testing began, are available. They show the number of cases of these diseases occurring in that year per 100,000 population.
The extra radiation that one gets in Denver from cosmic rays is many times greater than the fallout radiation. But the table shows no increased incidence of bone cancer or leukemia. On the contrary—the incidence of these diseases is actually lower in Denver.
Not all of the natural background radiation is due to cosmic rays. Part of the background comes from natural radioactive elements in the soil and in the drinking water. These include uranium, potassium⁴⁰, thorium and radium. Radium behaves like calcium and strontium, and gets deposited in our bones. All these effects are, to the best of our knowledge, at least as intensive in the Denver area as in San Francisco or New Orleans.
One possible explanation for the lower incidence of bone cancer and leukemia in Denver is that disruptive processes like radiation are not necessarily harmful in small enough doses. Cell deterioration and regrowth go on all the time in living creatures. A slight acceleration of these processes could conceivably be beneficial to the organism. One should not forget that while radiation can cause cancer, it has been used in massive doses to retard and sometimes even to cure cancer. The reason is that some cancer cells are more strongly damaged by radiation than the normal cells.
In spite of the table, however, there may actually be an increased tendency toward bone cancer and leukemia thatresults from living in Denver. If so—and this is the main point—the effect is too small to be noticed compared to other effects. We must remember that Denver differs from New Orleans and San Francisco in many ways (besides altitude), and these differences may also influence the statistics.
A more thorough consideration of the background radiation gives further evidence that this radiation is more important than the present or expected effects of Sr⁹⁰. The radium deposited in our bones from drinking water has been observed to reach values as high as 0.55 roentgens per year. Furthermore the heavier and slower alpha particles emitted by radium cause ionization processes which occur in closer spacing and are therefore more damaging than the ionization due to Sr⁹⁰. To make things worse radium is deposited in our bones in little nodules (hot spots). Thus the possibility of local damage is enhanced.
The background radiation to which we are exposed varies for some unexpected reasons. It has been pointed out recently that brick may contain more natural radioactivity than wood. The difference between living in a brick house and living in a wood house could give rise to ten times as much radiation as we are currently getting from fallout. (The additional radiation from the brick might be as much as 0.03 roentgens per year.)
Human beings are subject to radiation not only from natural sources, but also from man-made sources. One of these is wearing a wrist watch with a luminous dial. Another is having X-rays for medical purposes. Both of these sources give much more radiation than the fallout.
Of all ionizing radiation to which we are exposed the X-rays are most important. In some cases medical X-rays have intensities which are noticeably harmful. Yet this damage is practically always of little consequence compared to the advantage from correct recognition of any trouble that the X-ray discloses.
We may summarize in this way. Our knowledge of the effects from the fallout is deficient. We cannot say exactly how many lives may be impaired or shortened. On the other hand, our knowledge is sufficient to state that the fallout effect is below the statistically observable limit. It is also considerably less than the effect produced by moving from sea level to an elevated location like Denver, where cosmic radiation has a greater intensity. It is also less than having a chest X-ray every year. In other words, we know enough to state positively that the danger from the world-wide fallout is less than many other radiation effects which have not worried people and do not worry them now.
We have compared radiation from the fallout with radiation from other sources. It is also possible and helpful to compare the fallout danger with different kinds of dangers. For this purpose it is convenient to express all dangers in terms of a reduced life-expectancy. For example, smoking one pack of cigarettes a day seems to cut one’s life-expectancy by about 9 years. This is equivalent to 15 minutes per cigarette. That cigarettes are this harmful is, of course, not known with certainty. It is a “best guess,” due to Dr. Hardin Jones, based on an analysis of statistical data. A number of Dr. Jones’ statistical findings are listed in the following table:[13]
The reader will see that the world-wide fallout is as dangerous as being an ounce overweight or smoking one cigarette every two months.
How people get radiationAverage dose in roentgens per year
How people get radiationAverage dose in roentgens per year
The objection may be raised that the fallout, while not yet dangerous, may become so as more nations develop and test atomic weapons. On this point we can only say that the future is not easy to predict. Some factors, however, justify optimism. We are learning how to regulate the fallout by exploding bombs under proper surroundings. Development of clean bombs will greatly reduce the radioactivity produced. Deep underground tests will eliminate fallout altogether. The activity put into the atmosphere in 1954 was considerably greater than the activity released in any other year. It is highly probable that the activity produced by United States tests will continue to decline.
Finally, we may remark that radiation is unspecific in its effects. Chemicals are specific. About the effects of a new ingredient in our diet, in our medicine, or in the air we breathe, we know much less than we know about radiation. If we should worry about our ignorance concerning our chemical surroundings as we worry about the possible effects of radiation, we would be condemned to a conservatism that would stop all change and stifle all progress. Such conservatism would be more immobile than the empire of the Pharaohs.
It has been claimed that it is wrong to endanger any human life. Is it not more realistic and in fact more in keeping with the ideals of humanitarianism to strive toward a better life for all mankind?
Radiation may hurt the individual. It may also be harmful for our children and hurt the race. We have seen that the danger from the radiation due to testing is small compared to many risks which we habitually take and almost always ignore, which in fact we have to ignore to continue to live in this civilized world. In addition we are not even quite sure that the danger to the individual is real.
There can be little doubt, however, that radiation does produce some harmful changes in our children. What seems even more frightening, is that these changes may not show up in our children but only in their children or further progeny. A danger which may lie hidden for generations might seem more terrifying, especially as it has often been repeated that all such radiation effects are harmful.
We transmit our properties to coming generations in a most curious and concentrated fashion. From the mother and the father a child inherits a number of chromosomes, twenty-four from each.[14]These are structures along which the actual carriers of the properties—the genes—are strung up.
We are beginning to understand something about the nature of the genes. They seem to be very big spiral molecules. They carry the master plan of our body and even of our character in a strange chemical code.
The laws of heredity are complicated because of the fact that the same property is influenced by a gene from each parent. Frequently these two genes dictate different behavior and then the result is a compromise, sometimes evenhanded, sometimes unbalanced. But of the two genes only one will find its way to the child of the next generation. The compromise is temporary and original properties may emerge again. Which one of any pair of chromosomes (or of the two assemblies of genes) carries on is a matter of chance. In the world of the cells as in the world of atoms it is chance that determines the future—not fate.
Of all these facts we need be particularly interested in one. The units of inheritance are rather constant but not quite immutable. There is a small possibility that any gene may suffer a mutation. That is, it may turn into a new chemical, carrying a new code and new properties.
A gene is an extremely finely and precisely constituted object. It must be so in order to carry all the racial past in so little material. A mutation due to chance will spoil this order in almost every instance. The great majority of mutations are detrimental. Many are lethal.
It is an incredible fact that these random mutations, almost always harmful and never proceeding according to any plan, should have been responsible in the very long run for all the many beautiful and perfect living creatures that nature has produced (and this includes the human race). The thread leading from single cells to cell colonies, worms, fishes, vertebrates, mammals and human beings does certainly not seem to be the work of chance. Much less does it seem to be the work of a gamble taking one chance of a small improvement against a thousand chances of deformity or death. Neverthelessit is such a terrible game of chance which has produced both the human body and in some manner also the human spirit.
Big numbers are strange things and when each member of a huge assembly must be given individual attention then the numbers are even harder to appreciate. Billions of contemporary lives in billions of distinct generations have led to the incredible outcome: the harmony of life produced by gambling.
Radiation is surely disruptive. It does cause mutations. Since the genes appear to be single molecules, a single process of ionization or excitation is likely to result in a change. As has been said before there is doubt whether or not cancer and leukemia can be caused by exceedingly little radiation. There is little doubt, however, that mutations can be caused by any small amount of radiation. The less radiation the less the chance. But the chance will always be there.
A very great increase in the natural rate of mutations could indeed have terrifying effects. We can be quite certain, however, that radiation from atomic tests will increase the chance of mutations by only a very small amount.
The argument is essentially the same as the one concerning the danger to the individual. The tests are responsible for 0.001 or 0.002 roentgens per year to the human reproductive cells. This is equivalent to approximately 0.05 roentgen per generation. Most of this radiation is due to gamma rays from Cs¹³⁷ which has been deposited on the ground or absorbed in the body. The number of mutations caused by this radiation is to be compared with the number of natural mutations.
Some of the natural mutations are caused by heat and chemicals. Some are due to background radiation, to cosmic rays or to gamma and beta rays emitted by natural radioactive substances in or near our bodies. Our best estimate is that 10 per cent of the natural mutations are due to the background radiation.
Over a period of one generation the background radiation dosage to the human reproductive cells is approximately five roentgens. Assuming a simple proportionality between dosage and the number of mutations, it follows that fifty roentgens would be required to induce a number of mutations equal to the total number of natural mutations (from background radiation and all other causes). That is, fifty roentgens is a “doubling dose.”
The atomic tests are therefore increasing the number of mutations by about 0.05 ÷ 50, which is 0.1 per cent. This kind of increase in the rate of mutations would certainly not seem to be a serious reason for worry.
Actually the number of mutations from the tests is very small even compared to geographical and altitude variations in the natural radioactivity. The Inca empire existed for many generations in the high country of Peru. The people of Tibet have been exposed for generation after generation to the greater cosmic ray intensity which bombards them through a thinner layer of atmosphere. These people have been exposed to much greater additional radiation than anything which is caused by atomic tests. Yet genetic differences have not been noticed in the human race or for that matter in any other living species in Peru or Tibet. We are certainly talking here about questions which may strike hard on some individuals but which from the point of view of the community or race are not serious.
It has been often repeated that all mutations due to radiation are harmful. There is every reason to believe that mutations due to radiation are not different in kind from other mutations. Should we then seriously believe that all mutations are harmful? That most of them are is admitted. If all of them were indeed always harmful, we must deny the simplest facts of evolution.
There will be some who maintain that the human race is not capable of improvement. Such an argument is irrefutable.It is also unreasonable. What cannot be further improved is perfect, and not many people will maintain that our species can claim perfection.
Another and much more plausible argument has been advanced: In the wild state living species do perfect themselves by means of natural selection. Human society by caring for the imperfect and defective individual has eliminated natural selection. Therefore further mutations will not improve mankind.
It is very hard to discuss this question for the simple reason that the argument involves the interaction of two processes extremely different in magnitude and in fact different in kind. On the one hand it concerns itself with evolution which proceeds in the slow deliberate way of a glacier. On the other hand it focuses attention upon the process of human civilization with its technical and social changes which has gained momentum like an avalanche. The momentum is still there and it is still increasing and where we shall land we do not know. To consider the motion of the glacier while being carried along by the avalanche puts things completely out of proportion. Long before the present rates of mutation could have any effect upon the human species we shall live in a very different world and we shall have started to influence our own behavior including those of selection, natural or otherwise, in ways which today we cannot foresee.
If we discuss the question how civilization will influence natural selection, we shall not do it with the hope of arriving at a firm answer. We shall do it rather in order to illustrate how doubtful all the arguments are which concern the interplay of two processes which cannot be measured in the same scale.
It is true that we can and do preserve the lives of children who, because of inherited weaknesses, would perish under natural conditions. It is true too that we do this for reasons and for feelings concerning the individual and we do it withoutregard to the consequences to the race. However, under our present condition of civilization a disease which can be corrected by administering chemicals or using the surgeon’s knife is no longer effectively a disease. In our present condition such a life can be as valuable to society and to the race as a life which does not have these superficial shortcomings. That we can and do preserve more life in this manner only emphasizes that under present conditions biological differences which used to be important no longer matter.
On the other hand, in social living many properties which used to be indifferent for a wild being have become of great significance. Ability to communicate and to get along with our fellows is not the only one, but is perhaps the most obvious one of such properties. The struggle for existence has become more gentle, and the chance of any individual to live on in his children is governed by new ways of behavior. Nevertheless the difference between the individual adapted to civilized living and the one who is not adapted is of great importance and will become of greater importance. It is likely that civilization will not eliminate evolution of the race. Rather it will direct it into new paths.
But the greatest change might be expected from an entirely different direction. We are going to understand in real detail the intricacies of human inheritance. Then we shall be faced with problems and shall find possibilities of an entirely new and different kind. The interest of a person in his children is not a superficial one. It is one of the most strong and lasting forces in biology, sociology and history. A clear understanding of the details of inheritance may bring about some grave difficulties because a new situation is never fitted easily into existing patterns of living. In the end more understanding may bring about improvements of a kind beside which all the worthwhile things that have been so far accomplished, might look unimportant.
The real importance of radioactivity for heredity does notlie in the fact that we may speed up the glacier by one inch in a millennium. The real importance of nuclear radiation is rather that it is helping us to understand the strange processes of life and the curious substances which connect one generation to the next.
Nuclear explosions seem horrible for many reasons. They were presented to an unprepared world as a dramatic surprise—as the climax to the slaughter of the Second World War. Their power of destruction is fantastic. Before we had adjusted our thinking to atomic bombs, an even more potent tool of warfare—the hydrogen bomb—was invented. Worst of all: To the fear of destruction there was added the dread of the unknown. It is not surprising that discussion of nuclear weapons has not proceeded on a purely rational level.
To the nightmare of the atomic and hydrogen bombs has been added—not as a reality but as a further threat—the cobalt bomb. The idea of such a bomb is to intensify the most terrifying aspect of nuclear explosions: the radioactivity. This radioactivity could be used to poison the enemy. It could get out of hand and poison everyone.
Cobalt⁶⁰ is a radioactive isotope of the fairly common metal cobalt. It can be easily produced by absorbing slow neutrons in the natural and stable cobalt⁵⁹. It has a half-life of five years and it emits penetrating gamma rays. These properties make it useful in cancer therapy.
Many cancerous growths are more sensitive to radiation than healthy tissue. Therefore radiation can be used to reduce—sometimes even to destroy—dangerous tumors. The penetrating rays of cobalt⁶⁰ can reach the cancer even deep inside the human body. The lifetime of cobalt⁶⁰ is long enough so that this substance is easily installed in hospitals.
But the same properties which make cobalt⁶⁰ useful also make it potentially dangerous. A nuclear explosion produces many neutrons and these could be absorbed in ordinary cobalt. The radioactivity produced in this way lives long enough to become widely distributed. Its ray can easily penetrate a foot of masonry and several hundred feet of air. A cobalt bomb would indeed be a most unpleasant object. (Seepictures 7 and 8.)
One widely discussed possibility is that future nuclear tests will be used to develop a cobalt bomb or other bombs for radiological warfare. Actually tests have little to do with the cobalt bomb. Once one has a powerful nuclear weapon, such as a hydrogen bomb, it is relatively easy to make a radiological bomb. Further tests are not necessarily required. To the extent that any testing need be carried out, it is only necessary to activate a moderate amount of substance to find out in what way a certain bomb would function as a tool of radiological warfare. Tests of this kind would add only a negligible amount of radioactivity to the atmosphere. Therefore, in connection with the test program we need not worry about the cobalt bomb or any related experiment. The question of the cobalt bomb or radiological warfare in general is not whether it is feasible—it is—but rather whether it serves a useful military purpose.
It is not impossible that situations might arise in which radiological warfare could be militarily advantageous. Instead of cobalt, other materials may be placed near the nuclear bombs. In this way other radioactive substances can be produced. By an appropriate choice of such a substance onecan get a radioactive material which, when deposited near the point of explosion, will contaminate the site for a time which can be adjusted to the military requirements. The lifetime of the radioactive material may be long enough to give an opportunity to the people to escape from the contaminated area. At the same time, one may precipitate almost all the activity near the explosion so that distant localities would not be seriously affected. It is conceivable, therefore, that radiological warfare could be used in a humane manner. By exploding a weapon of this kind near an island one might be able to force evacuation without loss of human life. No instrument, not even a weapon, is evil in itself. Everything depends on the way in which it is used.
Public opinion has all but persuaded itself that nuclear weapons will be used not for a military objective but to terrorize and kill the greatest number of people. This is technically feasible. In fact, it does not even require the atomic bomb. For the last hundred years this possibility has been with us. Bacteriological warfare may cause widespread destruction. Yet no one has resorted to this horrible way of making war. We do not believe that anyone will expose his enemy and ultimately himself to indiscriminate bacteriological or radiological destruction. Our guarantee against this danger is not that it cannot be done. Our guarantee is the better and saner part of human nature: the will to survive and the feeling of common decency.
Many people feel that tests should be discontinued. This feeling is widespread and strong. The question of tests is obviously important. It may influence our security as individuals. It certainly will influence our security as a nation. If in a free, democratic country the majority believes that something should be done—it will be done. The sovereign power in a democracy is “the people.” It is of the greatest importance that the people should be honestly and completely informed about all relevant facts. In no other way can a sound decision be reached. The basic and relevant facts are simple. The story can be presented without unnecessary frills or undue emotion. When this has been done, the right decision will be reached by common sense rather than by exceptional cleverness.
Unfortunately much of the discussion about continued experimentation with nuclear explosives has been carried out in a most emotional and confused manner. One argument concerning tests is so fantastic that it deserves to be mentionedfor that very reason: It has been claimed that nuclear explosions may change the axis of the earth.
Of course, nuclear explosions do produce such changes. Only the changes are so small that they are impossible to observe and even difficult to estimate. Searching for effects connected with past tests that may displace the axis of the earth, or the position of the North Pole, we could find no effect that would have caused a change of position even as great as the size of an atom. One could design tests with the specific purpose to produce such a change, but these man-made effects could not be compared even remotely with the forces of nature. The motion of the Gulf Stream has a small effect on the North Pole; but this effect is incomparably greater than what any nuclear explosion could accomplish. It is good to know that the old top on which we live does have some stability.
The argument about world-wide radioactive fallout is more serious. It is asserted that fallout is dangerous and that we are ignorant of the extent of the danger.
In a narrow, literal sense both these statements are correct. But in the preceding chapters we have seen that the danger is limited. We do not know precisely how great it is. We do know, however, that the danger is considerably smaller than the danger from other radiations to which we continue to expose ourselves without worry. The danger from the tests is quite small compared with the effects of X-rays used in medical practice. The fallout produces only a fraction of the increase in cosmic ray effect to which a person subjects himself when he moves from the seashore to a place of higher altitude like Colorado. People may or may not be damaged by the fallout. But it is quite certain that the damage is far below a level of which we usually take notice.
Fallout in the vicinity of the test sites did cause damage. In the past this damage was not great although in one Pacific test it was serious. Precautions have been increased andwe may hope that future accidents will be avoided altogether. The safety record of the Atomic Energy Commission compares favorably with other enterprises of similar scale.
It seems probable that the root of the opposition to further tests is not connected with fallout. The root is deeper. The real reason against further tests is connected with our desire for disarmament and for peace.
There can be no doubt that the desire for peace is most deep, and this desire is felt by all thinking and honest people on our earth. All of us certainly hope that the catastrophe of war can be avoided. This great and universal wish for peace is the driving force behind the desire for disarmament. In the minds of most people it would be an important step toward disarmament if the testing of nuclear weapons were stopped by all nations. This belief is widely held, but it is not necessarily well-founded. In fact, there are arguments on the other side which should be considered carefully.
It is generally believed that the First World War was caused by an arms race. For some strange reason most people forget that the Second World War was brought about by a situation which could be called a race in disarmament. The peace-loving and powerful nations divested themselves of their military power. When the Nazi regime in Germany adopted a program of rapid preparation for war, the rest of the world was caught unawares. At first they did not want to accept the fact of this menace. When the danger was unmistakable, it was too late to avert a most cruel war, and almost too late to stop Hitler short of world conquest. Unfortunately, disarmament is safe only when no one wants to impose his will by force of arms upon his neighbors.
In the uneasy world in which we live today no reasonable person will advocate unilateral disarmament. What people hope is that all sides will agree to reduce their military power and thereby contribute to a more peaceful atmosphere. The elimination of tests has appeared possible and proper for tworeasons. One is that tests are conspicuous, and therefore it is believed that we can check whether or not testing has actually been stopped by everyone. The second reason is that nuclear explosives already represent such terrifying power that further tests appear useless and irrational. These arguments are simple and almost universally accepted. They are based on misconceptions.
A nuclear explosion is a violent event, but in the great expanses of our globe such tests can be effectively hidden if appropriate care is taken to hide them. There can be no doubt that this is possible. The question is only how much it costs to hide a test and how big is the explosion that can be carried out in secret for a certain amount of expenditure.
If an agreement were made to discontinue the tests, the United States would surely keep such an agreement. The very social and political structure of our country excludes the possibility that many people would collaborate in breaking an international undertaking. Whether Russia would or would not keep such an agreement would depend on the ingenuity of the Russians, on their willingness to make economic sacrifices, and on their honesty. Of these three factors we can have a firm opinion about the first. The Russians are certainly ingenious enough to devise secret methods of testing. As to the other questions, whether the Russians will want to invest the effort and whether they will be bound by their word, we feel that each man is entitled to his own opinion. According to past experience, an agreement to stop tests may well be followed by secret and successful tests behind the iron curtain.
In a more general way we may ask the question: Is it wise to make agreements which honesty will respect, but dishonesty can circumvent? Shall we put a free, democratic government at a disadvantage compared to the absolute power of a dictatorship? Shall we introduce prohibition in a new form, just to give rise to bootlegging on a much greater scale? Itis almost certain that in the competition between prohibition and bootlegging, the bootlegger will win.
All of these arguments, however, would become irrelevant if it were true that further testing would not accomplish any further desirable result. It has been said and often repeated that we now possess adequate nuclear explosives to wipe out the cities of any enemy. What more do we need?
Our main purpose in further experimentation with nuclear bombs is not, of course, to make city-busters more horrible. We would prefer not to have to use our nuclear weapons at all. We keep them as a counterthreat against the danger that we ourselves should be subjected to a devastating attack. To understand what we are actually trying to do in the tests, we have to take a closer look at some military problems.
In the Second World War strategic bombing was used for the first time on a really massive scale. It may well be and, in fact, it is probable that such strategic bombing will not be repeated in the future.
There are two military reasons for the bombing of cities. One is that factories are located in cities, and these factories support the war effort. The other reason is that cities are centers of transportation through which the supplies of war materials pass. By destroying these centers the flow of the war supplies can be interrupted.
Nuclear warfare is likely to be quite different from past conflicts. The great concentration of firepower which a nuclear weapon represents makes it possible to attack on enemy anywhere, at very short notice. This is true no matter what the particular target is, whether one is trying to attack the planes, ships, tanks, or troop concentrations of an enemy. The great mobility of nuclear firepower makes it highly probable that the nuclear conflict will be short. What the factory produces during this conflict will not affect the outcome of the fighting. The only weapons on which anyone can rely arethe weapons which are already stockpiled. Therefore, it will be militarily useless to bomb factories.
The same fact of mobility also implies that no great flow of war material will need to be maintained. Practically all movement can be executed by light and fast methods, by planes, submarines, and small battle groups. Under these conditions the cities will lose their importance as centers of transportation.
The only purpose in bombing cities will be to spread terror among the enemy. This was rarely done in past wars. In fact, terror is self-defeating because it provokes retaliation from the other side.
We believe that the role of nuclear weapons in a future war is by no means the killing of millions of civilians. It is rather to stop the armed forces of an aggressor. This is not easy to do because it requires not only nuclear weapons, but very special kinds of nuclear weapons which are hard to develop and harder to perfect. But with proper experimentation and proper planning the defensive use of nuclear weapons is possible.
The idea of tactical nuclear weapons is not new. The possibility of using nuclear explosives in small wars has been frequently discussed. What kind of weapons do we need in order to fight these small wars and to defend the freedom of people wherever such defense becomes necessary? It has often been suggested that in small wars, small weapons will be used, while big weapons are appropriate for big wars. Such a statement is much too simple and has no relation to reality. In every case the right kind of weapon is the one which performs the job of stopping the enemy’s armed forces without inflicting unnecessary loss on the innocent bystander. For this purpose we need a great number of weapons which are adaptable to specific purposes, which are easy to transport and easy to deliver, and give rise to the kind of effect which the situation requires.