The Global Health Implications of a Nuclear War


A nuclear bomb explosion. Source: Wikimedia Commons.

In recent years, the topic of nuclear weapons has been a hotbed of political controversy across the globe. Many argue that the widespread use of nuclear weapons is a more plausible reality today than ever before, but the threat of nuclear war has existed ever since the culmination of the US Manhattan Project with the first nuclear bomb detonation in Alamogordo, New Mexico on July 16, 1945.1 Today, at least nine nations currently possess a combined estimate of 15,500 nuclear warheads.2 Over 90% of these belong to Russia and the United States, each of which have over 7,000 nuclear weapons.2 Although initial major nuclear reports from the 1980s focused on the threat of nuclear war between the US and the former Soviet Union3, today China, India, and Pakistan are all pursuing new missile technology, sea-based nuclear deliveries, and other nuclear advances. Additionally, North Korea is continuing to violate previous denuclearization pledges by advancing its nuclear weapon program.2 Never before has the world seen such widespread nuclear capabilities, and never before has the potential extent of nuclear war been so great.

This imminent nuclear threat poses major challenges for global health. Aside from the immediate resulting harm – namely the massive casualties in the immediate vicinity of a nuclear explosion due to blast, heat, and fallout – a major nuclear conflict (typically discussed on the scale of 100 Hiroshima-sized bombs) would upend the entire planet, leaving global health in a state of abysmal ruin. Researchers forecast spikes in cancer and genetic defects, mass starvation, and the global spread of epidemics due to a variety of environmental changes resulting from the nuclear explosion.

Immediately following a nuclear explosion, the resulting blast would kill almost everyone – even those in nuclear shelters – within a close range (up to two kilometers).3 Outside of a 10 kilometer range, the probability of death drops off, but people in the area would still be deeply affected by the long-lasting impacts of a nuclear detonation.3 By the second half of the Cold War, at the height of the global nuclear weapon count, researchers estimated that up to 500 million people could be killed immediately from the explosion of weapons in a nuclear war,3 a figure that has since been deemed an underestimate by modern models4 and is highly dependent on the population density of the directly bombed areas. Beyond these immediate impacts, which would largely occur within 24 hours of a nuclear explosion, radiation and changes in the environment would create long-lasting mass health problems that could affect the human population for centuries.

One of the most harmful effects of a nuclear war would come in the form of much higher levels of cancer incidence in the human population. A 2008 study suggests a “modest” estimate of 5 teragrams (Tg) of elemental carbon (soot) emissions from a regional nuclear conflict could elevate stratospheric temperatures 30 degrees Celsius, reducing 20% of the global ozone layer, with losses as large as 70% at northern high latitudes for as long as five years.4 This would dramatically increase both the duration and intensity of UV radiation reaching the Earth’s surface, in turn raising cancer rates. Additionally, although the mechanisms are not well known, evidence suggests a nuclear conflict could affect the exposure pathways of chemicals and toxins produced by nuclear weapons, further complicating the risk of cancer in the human population.5

Several of the most widespread health effects resulting from a nuclear war are all borne out of the same issue: destruction and lack of food and agriculture. The resulting major health issues are catastrophic, including foodborne diseases and malnutrition, which in turn give way to developmental and genetic defects. Researchers estimate that 5 Tg of elemental carbon emission in the wake of a regional nuclear conflict would be enough to cause the lowest temperatures seen on Earth in 1000 years.4 In contrast, emissions totaling 75 Tg, less than half of the predicted emissions in a hypothetical nuclear war between current global nuclear powers based on nuclear arsenals regulated by the Treaty of Strategic Offensive Reductions, would be sufficient to reach temperatures around those of the last Ice Age. Furthermore, global rainfall could be reduced by more than a quarter of its annual levels.4 This would drastically shift the growing season of crops, and in turn, the available food supply. For example, a nuclear war simulation in several provinces of China yielded an almost 100% reduction in rice crops in the northern areas, and reductions ranging from 10-42% in crop yield of southern areas.6 Climate models for a 5 Tg elemental carbon emission following a nuclear conflict correspond to a reduction in growing season rivaling the shortest average growing season length observed in “Midwestern corn-growing states.”4 This leads to food shortages and the proliferation of food contaminants due to changing ecosystems and the proliferation and termination of different species in response to changing precipitation and temperatures. In addition, a decline in food supply and adequate nutrition would affect human development during fetal and early youth stages of development. Combined with higher rates of exposure to toxic contaminants, these factors create the perfect environment to give rise to higher incidences of birth defects and genetic issues, due to improper developmental nourishment.

In the Quang Ngai province of southern Vietnam, a baby is born with a cleft palate, a common birth defect. An increase in radiation exposure in the aftermath of a nuclear war would increase the frequency of similar birth defects. Source: John Urban.

These massive, long-standing changes caused by a nuclear clash would also affect other aspects of global health. The increase in air pollution due to the release of particulates and aerosolized toxins, as well as the exposure to seasonal air elements such as pollen as a result of changing growing seasons, could contribute to high incidences of asthma and related respiratory diseases. Increased temperatures in certain regions and changing disease vectors, as a result of climate and ecosystem shifts, would likely increase cardiovascular disease and stroke rates. Extreme weather events, such as monsoons, hurricanes, droughts, and wildfires, due to changing ecosystems and water supply, could increase mortality rates among those in the affected areas. Rates of waterborne and vector-borne diseases, such as cholera, malaria, and giardia, could skyrocket in response to shifts in precipitation patterns, coastal environments, and relocation of large populations. Lastly, neurological diseases and mental health disorder rates would also likely increase, as a result of higher stress placed on individuals from factors such as geographic displacement, death of relatives, extreme stress, exposure to biotoxins, and malnutrition.

Although total global nuclear weaponry has decreased three-fold since its peak towards the end of the Cold War, a nuclear war still remains a massive threat to the stability of human health around the world.7 Much of this stems from the refusal of every nation currently in possession of nuclear weapons to disclose the official contents of their respective arsenals. Thus, much of what we know about current nuclear warhead counts is rooted in various international treaties and data concerning nuclear delivery systems in each nation and in regular releases of the Bulletin of the Atomic Scientists.8 Other nuclear estimates are based on approximations of fissionable material in nuclear weapon states, such as plutonium produced in nuclear reactors, and attempts to match up the data with plausible weapon assembly counts. This has been done by the Institute for Science and International Security for nations including India, Israel, North Korea, and Pakistan, but leave much uncertainty and lack of confirmation associated with the estimates.4 This international silence on nuclear weaponry is one of the major roadblocks impeding scientists’ ability to understand and tackle the issues of global health in the wake of a nuclear war. Without more exact and specific data on the sheer size and potentials of the weapons in each nuclear nation, we are unable to wholly predict the global health effects of a major nuclear conflict. What is clear, however, is the imperative need for further reduction of nuclear inventories at a much faster speed. As early as the 1970s, the nuclear programs of the US and Russia were capable of overkill, a term coined by Nobel Peace Prize winner Philip Noel-Baker, referring to the ability to “exterminate a population more than once,” and something Noel-Baker claimed the world might be capable of doing “ten times over.”3

Ultimately, our lack of information about current nuclear stockpiles impedes the ability to adequately evaluate, assess, and attack the global health crisis that would undoubtedly occur following the use of multiple nuclear weapons. Armed with the current bed of nuclear information available, we must identify major potential global health issues and work to provide solutions as best we can. For cancer, this involves an active effort to understand carcinogen exposure pathways, investigate effects of ozone layer mitigation, investigate adaptation measures on rates of cancer incidence, and formulate oncologic therapies and treatments to optimize the best solution. For foodborne diseases and malnutrition, it is essential that we work towards a more informed stance on how changes in agriculture and fisheries impact food supply and nutrition, a stricter supervision of disease-related agents, and an understanding of intricate food and organism relationships to further our ability to brace healthcare sectors for an onset of new diseases. With regards to developmental and genetic defects, the crucial steps to improving this issue lie in a greater understanding of factors affecting both the supply and quality of food, as well as identification and mapping of pesticide use, toxic contamination, and expanding disease ranges.

In a study completed in the final years of the Cold War, one researcher declared, “What can be said with assurance…is that the Earth’s human population has a much greater vulnerability to the indirect effects of nuclear war [including damage to the world’s agricultural, transportation, energy, medical, political, and social infrastructure], especially mediated through impacts on food productivity and food availability, than to the direct effects of nuclear war itself,” and that ultimately “the indirect effects could result in the loss of one to several billions of humans.”9 Aside from the crucial reduction and eventual elimination of nuclear warheads from the face of the Earth, this preparation and research, which may seem futile in the face of immediate mass casualties following detonations of weapons in the event of nuclear warfare, will be the key to success against the threat of nuclear war.

Sarah Spaulding is a junior in Jonathan Edwards College majoring in Environmental Engineering and Ecology and Evolutionary Biology. She can be contacted at



  1. The First Atomic Bomb Blast, 1945 – EyeWitness to History. Retrieved from
  2. Martin, Brian. (1982). The global health effects of nuclear war. Current Affairs Bulletin, 59(7), 14-26.
  3. Toon, O. B., Robock, A., & Turco, R. P. (2014). Environmental consequences of nuclear war. Physics Today, 61(12), 37-42.
  4. Environmental Health Perspectives & National Institute of Environmental Health Sciences. (2010). A Human Health Perspective on Climate Change: A Report Outlining the Research Needs on the Human Health Effects of Climate Change. Environmental Health Perspectives.
  5. Xia, L., & Robock, A. (2012). Impacts of a nuclear war in South Asia on rice production in Mainland China. Climatic Change, 116(2), 357-372.
  6. World Nuclear Weapon Stockpile Report. (2016, March 2). Retrieved from
  7. Bulletin of the Atomic Scientists. (2016, September). Bulletin of the Atomic Scientists, 72(5), 1-350. Retrieved from
  8. M. A. Harwell, T. C. Hutchinson. Environmental Consequences of Nuclear War: Volume II: Ecological and Agricultural Effects, 2nd ed., Wiley, New York (1989).

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