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The Medical Implications of Nuclear War, Institute of Medicine. ~ 1986 by the National Academy of Sciences. National Academy Press, Washington, D.C. Nuclear Famine: The Indirect Effects of Nuclear War MARK A. HARWELL, PH.D., ~d CHRISTINE C. HARWELL, J.D. Cornell University, Ithaca, New York INTRODUCTION Over a 2-year period, the Scientific Committee on Problems of the Environment (SCOPE)-Environmental Effects of Nuclear War (ENU- WAR) project involved the participation of about 100 physical and at- mospheric scientists and an additional 200 agricultural and ecological scientists from more than 30 countries around the world in a unique undertaking to assess the global consequences of nuclear war. The at- mospheric scientists convened in a series of workshops, taking stock of their ongoing research and identifying the next issues to be examined with their computer models. From this emerged the characterization of the projected nuclear war-induced disturbances in the global atmosphere, with specified uncertainties and research needs (Pittock et al., 1985~. We on the biological side did not have the luxury of existing funded laboratory and modeling research projects on the consequences of nuclear war; in- stead, our mission was to inspect the current information, models, and understanding of how biological systems respond to stress. From these data and models, developed for reasons far removed from considerations of nuclear war, we synthesized a portrait of the global world after nuclear war (Harwell and Hutchinson, l9SS). The focus was on human population impacts mediated by disruptions in ecological, agricultural, and other life- support systems. The consensus that developed was stark: the indirect effects of a large- scale nuclear war would probably be far more consequential than the direct 117

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118 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES effects; and the primary mechanism for human fatalities would likely not be from blast effects, not from thermal radiation burns, and not from ionizing radiation, but, rather, from mass starvation. Whereas the direct effects of such a nuclear war could result in several hundred million human fatalities, according to several studies (e.g., Bergstrom et al., 1983; Am- bio, 1982), the indirect effects could lead to the loss of one to four billion lives. This conclusion is derived from considerations of the vulnerabilities of ecological and agricultural systems to the types of disturbances potentially associated with the occurrence of a large-scale nuclear war. Thus, the biological analyses were not linked to any specific nuclear war scenario or to any single specific projection of alterations in the physical environ- ment. This disassociation with particular scenarios was sought to avoid being limited by the current uncertainties of the physical estimates. Many of these uncertainties are irreducible, such as the specific details of an actual nuclear war, details that would only become certain as the war itself developed. Other uncertainties can be reduced by further investi- gations, such as the processes controlling smoke emissions and scavenging in the atmosphere. However, we cannot delay making biological and, especially, human impact assessments until such issues become fully re- solved. By examining the vulnerabilities of biological systems to classes of perturbations, our results can be applied to a full range of possible physical outcomes of nuclear war. Moreover, since the biological systems were found to be so sensitive to nuclear war-induced stresses, consensus was reached on biological responses and human impacts with perhaps less uncertainty than remains for the physical estimates. The categories of potential physical nuclear war-induced stresses that were examined are listed in Table 1. There was an emphasis on the effects from climatic disturbances, discussed in detail below, but other mecha- nisms for indirect effects were examined, including, in particular, effects from ionizing radiation and from increased levels of ultraviolet light. The climatic stresses were categorized with respect to the types of biological issues of importance. Specifically, an acute phase of climatic disturbance characterized by an abrupt onset of lowered temperatures and associated reductions in sunlight was identified as representing the potential envi- ronment in the first few days to weeks after a nuclear war. No single temperature or light decline was assumed; rather, the vulnerability of biological systems to brief episodes of chilling or freezing temperatures was examined. Similarly, for chronic-phase climatic disturbances, the vulnerability of biological systems to a few degrees' (Celsius) reduction in average temperatures persisting over the growing season, accompanied by 5-20 percent reductions in sunlight and possible decreases in precip- itation, was evaluated.

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NUCLEAR FAMINE: THE INDIRECT EFFECTS OF NUCLEAR WAR 1 19 TABLE 1 Nuclear War-Induced Stresses Examined Climatic Acute Temperature episodes of chilling or freezing Light-episodes of 1-10 percent normal insolation Chronic Temperature average decreases of 1C, 3C, 5C, 7C, 10C below nodal over growing season Light associated reductions in insolation by 5-20 percent Precipitation- reductions by 25-50 percent Radiation Local fallout Global fallout Focus on external gamma doses Other stresses Fire Ultraviolet-B radiation Atmosphenc pollutants In order to make these evaluations, no single set of experimental data was available; instead, a number of lines of reasoning were drawn on to exploit the full range of relevant information, including historical analogs, statistical analyses, laboratory physiological studies, simulation models, and expert judgment. The historical approach involved examination of specific episodes of environmental stresses and responses which have actually been experienced. For instance, incidents of freezing events in subtropical regions (e.g., Florida and southern Texas) were examined for their effects on fish populations, fruit trees, and other biological systems. Statistical analyses were done on data representing multiple years and multiple locations to determine the relationships among the physical en- vironment and biological systems. For instance, the relationship between the average air temperature experienced over growing seasons and the length of the frost-free period (a measure of growing season duration) was characterized statistically. Laboratory data were evaluated for physiolog- ical-level information, such as the growth rates of crop plants under lab- oratory conditions of different levels of temperature, light, moisture availability, and air pollutant exposures. Computer simulation models of ecological and agricultural systems were used for assessing the effects of chronic alterations in climate on crop yields and ecosystem productivity. And the judgment of scientists with expertise in specific agricultural and ecological systems was relied on to identify and evaluate available data and models and to extrapolate beyond the current experimental and his- torical records to obtain the best estimates of biological system responses to nuclear war. For the most part, the physiological-level data and expert

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120 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES judgment were used to evaluate acute vulnerabilities, and the less extreme perturbations associated with chronic-phase conditions were more suited to histoncal, statistical, and computer simulation analyses. These approaches were applied to each major biome type (Table 2 and Figure 1), covering freshwater, manne, and terrestrial ecosystems from the Arctic to the Southern Ocean and including the main grain crops in the northern temperate, Topical, and southern temperate regions of Earth. A number of international conferences were convened, each of which specifically addressed particular system types: northern temperate eco- systems were addressed at Toronto, Canada; northern temperate agncul- ture at Essex, United Kingdom; Topical ecological and agricultural systems at Caracas, Venezuela; Southern Hemisphere extratropical ecological and agricultural systems at Melbourne, Australia; and general biological re- sponses to radiation at Pans, France. Other conferences dealing with more generic biological issues were held in Stockholm, Sweden; New Delhi, India; Leningrad, USSR; and Essex, United Kingdom. A special confer- ence on the experiences and extrapolations from the Japanese nuclear bombings was convened in Hiroshima and Tokyo, Japan. At each con- ference, as broad a consensus as possible was sought among the experts, TABLE 2 Biome Approach to the Ecological Evaluations Northern Hemisphere terrestrial ecosystems Arctic and boreal Deciduous forests Coniferous forests Grasslands Arid and semiarid Northern Hemisphere aquatic ecosystems Freshwater Marine Estuarine Tropical ecosystems Evergreen rainforests Deciduous forests Montane-cloud forests Alpine Grasslands and savannahs Mangroves Southern Hemisphere extratropical ecosystems Australian ecosystems New Zealand ecosystems Southern Ocean and Antarctica

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122 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES with identification of unresolved issues and research needs. Many of the latter were addressed within the ENUWAR project itself, with specific statistical and computer simulation analyses being initiated. We used the reports of the various conferences, the results of the commissioned anal- yses, and additional studies conducted by the ENUWAR teams at Cornell University and the University of Toronto as the bases for writing Volume II of the ENUWAR report. This was subjected to an extensive review process, during which we ensured faithful representation of the consensus of the participants of the conferences; the completed book (Harwell and Hutchinson, 1985? provides the technical basis for the conclusions pre- sented here. ECOSYSTEM VULNERABILITIES The vulnerabilities of ecological systems were found to differ among ecosystems, types of disturbances, and time of year. For example, tem- perate forests were found to be most sensitive to acute, extreme temper- ature changes that occur during the spring or summer, whereas marine ecosystems were quite tolerant to changes in air temperatures. However, marine ecosystems were found to be very vulnerable to disruptions in the levels of incident sunlight, with acute reductions in insolation resulting in the collapse of phytoplankton and, perhaps, zooplankton populations on a large scale. Grassland ecosystems and the wheat-growing areas of Australia were assessed to be most vulnerable to chronic disturbances in precipitation, which is during the summer in the case of African grasslands and during the winter in the case of Australian wheat-growing areas. These conclusions were based primarily on the understanding of plant responses to light, temperature, and moisture levels; by contrast, animal responses, especially with respect to propagation of effects from one species to another through species-species interactions, were considered to be more speculative and probably never fully predictable. It is clear that inadequate data bases and simulation model resources exist for precise characterization of ecosystem responses, particularly to the less extreme range of physical disturbances. Nevertheless, the various approaches out- lined above suggest the cross-system vulnerability estimates provided in Table 3. Other analyses addressed the prospects for recovery for various eco- systems and the processes by which recovery could be affected. The consensus was that nuclear war-induced disturbances to the environment would include virtually every environmental problem of concern today- habitat destruction, species extinction, air pollutants, toxic chemicals, acid precipitation, ozone depletion only on a scale of totally unprecedented

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NUCLEAR FAMINE: THE INDIRECT EFFECTS OF NUCLEAR WAR 123 extent and intensity. Precisely what the full ecological ramifications of such stresses would be and the specific pathways that subsequent recovery would follow are urgently in need of a concerted research effort in the general field of stress ecology. Other considerations, however, show clearly that even without any disturbance to ecosystems, these natural systems could support only a very small fraction, on the order of 1 percent or less, of the current human population on Earth. The reason for this is that there would simply not be the base of utilizable energy sufficient to maintain 5 billion people if we did not have agricultural and other human-controlled systems to rely on. Thus, the carrying capacity of natural ecosystems is greatly exceeded by the current human population, and disruptions in human support systems that would force humans to rely substantially on natural systems for sustenance would necessarily lead to reductions in the human population. This fact provides the overriding incentive to examine the vulnerability of agricultural and food distribution systems to disruptions following a nuclear war. AGRICULTURAL VULNERABILITIES An examination of the vulnerabilities of agricultural systems showed that these systems are the most sensitive of any biological systems to changes in climatic conditions. There are several mechanisms by which climatic alterations translate into reductions or loss of crop yields. For most agricultural crops, temperature is the critical variable, although many crops are also sensitive to changes in precipitation and others can be limited by insufficient sunlight. Our studies focused on grain crops because these contribute the majority of the caloric inputs into the human diet on the global scale and because these crops are more effectively stored than most other food crops (e.g., fruits), a factor that could be critical in the aftermath of a nuclear war. Considering first the effects of temperature on grain yields, a number of factors are important: 1. Brief episodes of chilling or freezing temperatures The occurrence of even short-duration events of freezing temperatures during the growing season leads to loss of grain yields, as demonstrated in laboratory exper- iments and in the historical record; for example, in 1816 (the year without a summer) a series of frosts occurred during June through September, resulting in the loss of grain crops in the northeastern United States, eastern Canada, and western Europe. The occurrence of such episodes following a nuclear war could be expected to happen during the acute period, when average temperatures might be reduced by tens of degrees Celsius for days to weeks. Because of cloud patchiness during the period of early smoke cloud development, it could be expected that even greater tem

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126 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES perature reductions could occur for brief periods of time. Furthermore, during the chronic period that would extend into growing seasons one or more years after a nuclear war, average temperature reductions of rela- tively small amounts (in the range of 1C-5C) would be associated with episodes of chilling or freezing events. The historical record indicates that years with extreme low temperatures during the growing season (e.g., 1816) had average temperature reductions of less than 1C, which none- theless caused large crop losses. 2. Insufficient growing season length- Associated with the average reduction in temperatures over the spring-summer months, which is ex- pected during a chronic post-nuclear-war period, would be a shortening of the length of the growing season, with delay in the occurrence of the last day of freezing temperatures in the spring and an early onset of freezing temperatures in the fall. Several lines of evidence indicate that in the Northern Hemisphere continental regions of the mid-latitudes (i.e., the main grain-producing areas), on average, a 1C reduction in average tem- perature correlates to a 10-day reduction in the growing season length. For example, Figure 2 shows the average temperatures and growing season lengths for several locations in the United States over a several-year period. The importance of this phenomenon can be seen when a growing season is shorter than the growing season length requirements of the crop in order for it to reach maturity and produce a yield. Exacerbating this problem is the fact that reduced growing season temperatures result in the slower development of crop plants, thereby increasing the growing season length requirements for the crop to reach maturity. More on the growing season limitation aspects will be discussed below. 3. Insufficient growing degree-days-The term thermal time is used as a measure of the number of hours during the growing season that air temperatures exceed a specified base level by venous amounts and is calculated by multiplying the amount of time that the air temperature exceeds the base level times the increment of temperature above that level. For example, for a base level of 10C, 2 days with a temperature of 20C would have the same thermal time as 1 day with a temperature of 30C (i.e., 20 degree-days). As with growing season requirements, each variety of crop plant has a particular requirement for a total amount of thermal time, measured as growing degree-days, that is needed in order for the crop to mature. Below the threshold for thermal time, maturity does not occur and grain yields are lost. Again, during the chronic period after a nuclear war, the thermal times may be too low for grain production. 4. Insufficient integrated sunlight time A similar situation exists for the numbers of hours during the growing season during which sunlight levels exceed a certain amount. Simulations of Canadian wheat production showed that reductions in insolation by about 20 percent over the growing

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NUCLEI FAMINE: THE INDIRECT EFFECTS OF NUCLEI Wit 127 Climate cats 1955, 65, 75 20 . ~8 L ~ Mean annual 14 temperature . |8 L. 0 50 1 00 1 50 200 250 300 Frost-free length (days) FIGURE 2 Relationship between mean annual temperature and duration of frost- free period. Source: Harwell et al. (1985, p. 2791. Repnnted with permission from the Scientific Committee on Problems of the Environment (SCOPE). season led to a total loss of yield because the required threshold level was not exceeded. Thus far we have looked at mechanisms by which temperature and light reductions would lead to a total loss of crops for the growing season. In addition, the altered climate could be sufficiently benign so that some productivity remained possible, but the yields could be substantially re- duced from current levels. The mechanisms are as follows: 5. Reduced productivity in response to the physical environment- Laboratory data show those circumstances under which the thresholds of stress that would eliminate production are not exceeded, but less than optimal conditions reduce yields. These can result from reduced temper- atures, reduced light levels, and reduced precipitation levels. As an ex- ample of the latter, the historical record and computer simulations indicated that wheat yields in Australia are essentially linearly reduced with reduc- tions in rainfall; i.e., a 25 percent reduction in precipitation could be expected to result in at least a 25 percent reduction in yields. 6. Disruptions in energy inputs to agriculture The considerations to this point have focused on the yields that would be possible assuming continued high levels of energy inputs to agriculture, e.g., inputs of fer

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128 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES tilizers, pesticides, herbicides, fuel for tilling and harvesting, machinery, etc. However, in the aftermath of a large-scale nuclear war, the availability of these subsidies to agriculture, in combatant counties and in noncom- batant countries that rely on other countries for energy and commodity imports, would be severely disrupted or eliminated. Current yields of grains are heavily dependent on such energy subsidies, as demonstrated in Figure 3, which shows the tremendous increase in yields over the last four decades. This is largely in response to increases in energy subsidies. Assessments indicate that even in the absence of any climatic disturbances, disruptions in agricultural subsidies could lead to reductions in crop pro- duction by up to SO percent. The Agriculture Canada mode] of spring wheat production illustrates the potential effects of chronic climatic alterations on crop production following a nuclear war (Figure 4~. A map of the wheat-producing prov- inces of western Canada shows Me current boundaries for wheat production and the boundaries associated with a reduction in temperatures over the growing season on average by 1C, 2C, 3C, and 5C. The 1C reduction in average temperature results in a decrease in the potential growing area by a relatively small amount, but a 2C reduction in average temperature MEAN RICK YIELD 3200 3000 2800 KGIHA / / 2600 2400 2200 ~ 2000 1800 1 600 1400 ~ 1945 1955 1965 YEAR / / 1975 1 985 FIGURE 3 Mean rice yield. Source: Harwell et al. (1985, p. 343). Reprinted with permission from the Scientific Committee on Problems of the Environment (SCOPE).

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130 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES eliminates the majority of the growing areas; a 3C reduction would result in the complete elimination of any wheat production in Canada. This effect follows both from the reduction in the growing season length and in the insufficient levels of thermal time. Similar results were found for all other crops simulated, including crops that grow in much warmer climates such as soybeans (for which only a 4C-6C reduction in average temperature would eliminate yields in the southern United States). Rice was evaluated in particular because of its large share of the human diet on a worldwide basis and because a disproportionate number of im- mediate post-nuclear-war survivors would live in tropical and subtropical regions. We found that rice is the most sensitive of the grains to temper- ature reductions and that rice yields can be eliminated even in the absence of frost. In fact, at certain times during the growing season, temperatures below 15C lasting for only one or two nights would be adequate not to kill the rice plants but to preclude the formation and maturation of the rice grains. The historical evidence of rice production in Japan adds con- siderable support to the conclusion that rice is extremely sensitive to temperature; for example, when average summer temperatures are reduced in Japan by 1C-2C, crop failure occurs. From these and many other analyses and considerations, the strong consensus that emerged among the agricultural scientists associated with ENUWAR is that the acute phase of climatic disturbances could eliminate grain production in the Northern Hemisphere following a large-scale nu- clear war that occurred in the spring or summer and perhaps at other times of the year. Furthermore, the chronic-phase climatic conditions could also be expected to result in severe reductions or total elimination of yields of Northern Hemisphere grain crops, and Southern Hemisphere crops could also be adversely affected. Superimposed on these responses would be severe reductions in yields in response to the loss of energy subsidies, reductions in precipitation, and loss of arable land in combatant countries because of radioactive fallout. Additional yield reductions could follow enhanced levels of ultraviolet light and air pollutants. Clearly, there are multiple mechanisms by which food production could be disrupted on at least a hemispheric scale. A critical point in this is that these disruptions would occur at climatic disturbances at the very low end of the range of climatic changes projected to be likely to occur; thus, many of the un- certainties associated with climatic projections are irrelevant to the impacts on food production, since the levels of temperature changes under dis- cussion (e.g., tens of degrees Celsius average decreases in air temperatures in the grain-producing areas of the Northern Hemisphere for a spring- summer nuclear war) well exceed the thresholds necessary for elimination of grain yields.

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NUCLEAR FAMINE: THE INDIRECT EFFECTS OF NUCLEAR WAR 131 VULNERABILITY TO DISRUPTIONS IN FOOD AVAILABILITY These conclusions of the potential for massive disruptions in food pro- duction must be examined to assess the potential impact on humans. Since we cannot predict precisely by how much food production would be affected, because of the climatic and nuclear war scenario uncertainties discussed above, we again focused on the vulnerability of the human population to disruption in food production for 1 or more years. The key issue here is the amount and duration of food stores distributed around the world. In order to make this assessment, we examined data from the U.N. Food and Agriculture Organization and other sources for 15 countries on the quantities of grains stored, the current and estimated immediate post- nuclear-war population levels, the age structure of the population, and the minimal caloric consumption rates that humans require for subsistence. These 15 countries include about 65 percent of the human population and were selected to represent the range of situations in the world, including highly industrialized nations, likely combatants, underdeveloped coun- tries, Northern and Southern Hemisphere locations, tropics and temperate regions, and various population densities. Included in the analyses are the United States, the USSR, China, India, Australia, Japan, Costa Rica, Nigeria, and others. In addition, we acquired less extensive data to analyze the situation in 120 other countries, representing almost the entire world's population. Some simplifying assumptions were required: (1) grains were assumed to be fed only to humans, diverting the large quantities that currently are designated for animal feed; (2) the diet was assumed to chance to crimarv reliance on grains as opposed to current patterns of --I- -- rid ~ - ~ ~ ~ consumption; (~) no imports or exports or grains or energy supplies were assumed to occur in the aftermath of a large-scale nuclear war; (4) grain stores in combatant countries were assumed to be destroyed approximately in proportion to the loss of human life from direct effects of nuclear detonations, and (5) within each country, food distribution was assumed to work perfectly, such that each person would receive exactly the minimal amount needed for survival; furthermore, if it was found that there would be insufficient food to keep the full population in the country alive for 1 year, Den the maximum numbers of people that could be maintained were assumed to consume all the food stores, and no food was assumed to be eaten at all by those eventually doomed to starvation. Clearly this last set of assumptions provides a very considerable overestimate of the number of people that the food stores would actually keep alive and provides the physically limited upper value for population maintenance. The issues of societal disruption and other factors that could lead to a less-than-perfect

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132 PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES distribution of food in the aftermath of a nuclear war were not analyzed but require a concerted scientific study. The picture that emerged from the calculations of the food supply is as follows: 1. For a very few countnes, specifically those that are the major grain exporters, such as the United States, Canada, and Australia, the grain stores are, in principle, sufficient to keep the surviving population alive for a few years. Again, other factors might change this conclusion if food were not appropriately distributed, and long-term sole reliance on such grains could lead to nutrient deficiencies that were not calculated in our analyses. Also, these would likely be combatant countries, so the direct effects of nuclear detonations would be extensive. 2. For the rest of the world, including the vast majority of countries and of the human population, there is less than 1 year s food supply typically available during the year; for most countries the food duration is on the order of half a year or less. Furthermore, if the war were to occur prior to harvest (i.e., when food supplies were at their minimum levels), most of the stores would last only a matter of weeks to a few months. 3. Consequently, if food production were disrupted for one or more growing seasons, there simply would be not enough food to keep most of the survivors alive. Starvation, and the diseases and societal disruptions associated with starvation, would account for global declines in the human population. An indication of the extreme vulnerability of the Earn s human pop- ulation to sole reliance on food stores is seen in Figures Sa-c. Figure 5a shows the current population, as distributed within latitude bands, and the population distribution expected after a large-scale nuclear war (based on other analyses involving a severe-case impact on cities). Figure Sb com- pares the current population with the number of people who could be kept alive for one year under the assumptions discussed above if food stores were at their median level at the time of the nuclear war; Figure Sc shows the same, but for food stores at their minimum levels. These benchmark calculations make clear the extent of human vulnerabilities on a global scale. One other analysis is also noteworthy. Even if there were no impacts on food production at all, but only direct food and energy imports were disrupted, many countries would still be severely affected. Japan is the most striking case (Figure 6), where cessation in food imports would result in the loss of half the total population in Japan, even if 100 percent of current agricultural productivity could be maintained and if no nuclear detonations occurred in the country. In the much more likely situation of

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NUCLEI F~INE: THE INDIRECT EFFECTS OF NUCLEI Wit 133 (A) 80-71 N 70-61 N 60-51 N 50-41 N 40-31 N 30-21 N Lat ( ) 20-11 N 10-1 N O-9 S 10-19 S 20-29 S 30-39'S 40-49 S 50-59 S (B) . 80-71 N 70-61 N 60-51 N 50-41 N 40-3 1 N 30-21 N Lat() 20-11 N 10-1 N O-9 S 10-19 S 20-29 S 30-39 S 40-49 S 50-59 S (C) 80-7 1 N 70-61 N 60-51 N 50-41 N 40-31 N 30-21 N Lat ( ) 20-11 N 10-1 N O-9 S 10-19 S 20-29 S 30-39 S 40-49 S 50-59 S ~ _ __ _ _ 1 1 = S" l .~ 'NNSSx . . , ~ ~t I I I I 0 200 400 600 800 1000 1200 Population (millions) FIGURE 5 1982 population (solid bars) versus survivors of a nuclear war (hatched bars). A: Current population, as distributed within latitude bands, and population distribution expected after a large-scale nuclear war. B: Current population in comparison with how many people could be kept alive for one year if food stores were at their median level at the time of nuclear war. C: Same as in B. except for food stores at their minimum level. Source: Harwell et al. (1985, pp. 472 and 4801. Reprinted with permission from the Scientific Committee on Problems of the Environment (SCOPE).

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134 150 6 ~ 50 o PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES JAPAN /''~''''''''''''''''''''''''''''''''~ 100% of Production + I mports _ :. ::.: : I: ~ ~ ~ ....... ... ~::~ If: ~::~::~: if:: 100% of Production 150 100 50 o To o- FIGURE 6 Post-nuclear-war chronic phase agricultural effects in Japan. Source: Harwell et al. (1985, p. 475~. Reprinted with permission from the Scientific Committee on Problems of the Environment (SCOPE). food production impacts, such as from energy input disruptions or from mild climatic alterations, then 25 percent of current grain production could keep only about 15 percent of the population alive in Japan. CONCLUSION The indirect effects of a nuclear war, especially as mediated by dis- ruption in food availability, could be much more extensive than the direct effects. Furthermore, this risk is especially severe for noncombatant coun- tries- for the 4 billion or so humans expected to survive the immediate period after a nuclear war relatively physically unharmed. Thus, a fun- damentally different picture of the post-nuclear-war world results, where a large-scale nuclear war between the United States and the Soviet Union would probably result in more eventual fatalities in India than in the United States and the Soviet Union combined, and more people would die on the African continent than in all of Europe. Rather than reflecting images of Hiroshima and Nagasaki, a modern nuclear war would, for most of the people of the world, much more resemble current images of Ethiopia and the Sudan. ACKNOWLEDGMENTS This report represents the findings of the International Council of Sci- entific Unions' SCOPE-ENUWAR project, which involved the contri

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NUCLEAR FAMINE: THE INDIRECT EFFECTS OF NUCLEAR WAR 135 buttons of many scientists from all over the world (see Harwell and Hutchinson, 1985; Pittock et al., 1985~. We especially recognize the contributions by Wendell P. Cropper, Jr., Cornell University, and Thomas C. Hutchinson, University of Toronto. We wish to acknowledge He f;- nancial support provided by the SCOPE-ENUWAR Unit, Essex Univer- sity, United Kingdom, and by Cornell University, Ithaca, New York. REFERENCES Ambio. 1982. Nuclear War: The Aftermath. Special Issue of Ambio Vol. XI(2-3):75- 176. Bergstrom, S., D. Black, N. P. Bochkov, S. Eklund, R. J. H. Kruisinga, A. Leaf, O. Obasanjo, I. Shigematsu, M. Tubiana, and G. Whittembury. 1983. Effects of Nuclear War on Health and Health Services. Report of the International Committee of Experts in Medical Sciences and Public Health, World Health Organization. World Health Or- ganization Pub. A36.12. Geneva: World Health Organization. Harwell, M. A., and T. C. Hutchinson, with W. P. Cropper, Jr., C. C. Harwell, and H. D. Grover. 1985. Environmental Consequences of Nuclear War. Volume II. Ecological and Agricultural Effects. SCOPE 28. Chichester, U.K.: John Wiley & Sons. Pittock, A. B., T. P. Ackerman, P. J. Crutzen, M. C. MacCracken, C. S. Shapiro, and R. P. Turco. 1985. Environmental Consequences of Nuclear War. Volume I. Physical and Atmospheric Effects. SCOPE 28. Chichester, U.K.: John Wiley & Sons.