Regional Nuclear War in South Asia:
Effects on Surrounding Countries

Nicholas Wilson, MBChB, FAFPHM, MPH

Abstract

The potential effects of nuclear wars involving India, Pakistan, and China on neighboring non-combatant countries and the rest of the world are estimated by applying historical data on nuclear weapons effects and models for nuclear weapons usage to a range of plausible war scenarios involving these three countries. Lethal levels of local radioactive fallout could reach neighboring countries such as Nepal and Bangladesh after nuclear attacks on India. After an India-China conflict, radiation could spread globally and the external radiation alone might be expected in the long-term to cause around 0.6 million cancer deaths in the population living in latitudes 20 to 40 degrees North. Refugee flows, the spread of epidemics, and trade disruptions could have even more severe effects on neighboring countries than the impact from fallout. Nuclear weapon attacks on Pakistan, India, and China would have major impacts on neighboring countries and could spread radioactive fallout globally. Prevention of nuclear war through disarmament measures should be both a regional and global priority. [M&GS 1999;6:24-27]

During May 1998 both India and Pakistan undertook a series of nuclear weapons tests that dramatically demonstrated their nuclear weapon capabilities [1]. The current military situation between these countries is relatively unstable as there is major asymmetry in the size of their nuclear arsenals, along with asymmetry in conventional military power. The absence of sophisticated early warning systems and the very short warning times involved also raise the risk of surprise first strike attacks. In the last half of this century India has had three major wars with Pakistan and one with China [see Mian, Z., “The Politics of South Asia’s Nuclear Crisis,” M&GS 1998;5:78-85]; current border disputes between India and these other countries remain unresolved; and both India and Pakistan have increased military spending [2]. Given this situation, it is likely that this region poses the highest risk of a future nuclear war in the world. Indeed, the Bulletin of the Atomic Scientists considered the developments in India and Pakistan as a reason for moving the hands of their symbolic doomsday clock forward to nine minutes to midnight [3].

Methodology

The following two nuclear war scenarios are considered here (direct and indirect physical effects are based on scaling from the 1985 and 1986 SCOPE studies [4,5]) :

• An India-Pakistan war in which 25 15-kiloton (kt) Hiroshima-sized warheads are exploded on Pakistani targets and nine similar warheads are exploded on Indian targets (0.27 megaton (Mt) as airbursts, 0.24 Mt as surface bursts).
• A China-India war involving 25 Hiroshima-sized explosions on Chinese targets and 75 explosions on Indian targets (an even mix of 100 kt and 300 kt weapons; 7.5 Mt as airbursts, 7.9 Mt as surface bursts).

Arsenals and Delivery Systems

These scenarios represent around half the Indian strategic arsenal (assumed to contain 50 strategic nuclear weapons) and around three-quarters of the Pakistani arsenal (assumed to contain around 12 strategic weapons [6]). There is significant uncertainty surrounding the size of the weapons in these arsenals given the seismological data from recent weapons tests suggesting much smaller yields (less than Hiroshima-size) than the official information released by the Indian and Pakistani Governments [7]. China was assumed to use 30% of its 250 strategic nuclear weapons, which range from 100 kt to 300 kt for most long-range missiles (an average of 200 kt was used) [8]. The delivery systems assumed were aircraft for Indian and Pakistani weapons and aircraft and ballistic missiles for Chinese weapons [6].

As in a number of previous nuclear war scenarios [4], this study assumed an equal mix of air and surface nuclear explosions. In addition to the scenarios developed, the effect of the destruction of all of India’s 10 nuclear reactors (with a generating capacity of 1,695 MWE [9]) was considered in terms of its contribution to global fallout (based on a previous reactor attack model [4]).

Fallout

Results

An India-Pakistan War

Nuclear explosions of 15 kt over Indian and Pakistani cities in this scenario would probably kill far more people per city than the 120,000 killed at Hiroshima [11]. This is because of the larger and denser populations of modern Asian cities and the higher level of combustible materials and fossil fuels, which increase the risk of firestorms. One estimate for a 15-kt attack on Bombay suggested that 150,000 to 800,000 deaths would occur within a few weeks [12]. Therefore, it is likely that many millions of citizens in both countries would die in the short term from the 34 explosions occurring in this scenario.

The destruction of many major cities in the attacked countries would also be likely to lead to social and political chaos disrupting food production and distribution. This could lead to famines, which may not be alleviated by international aid measures in a turbulent post-war international environment. Also, the destruction of water and sewage systems could increase the risk of disease epidemics among the survivors. These indirect effects could ultimately cause far more mortality than the short-term effects, as has been previously predicted for larger nuclear wars [5]. Such effects could have an impact on neighboring countries, especially if there were large migrations of refugees crossing country borders to escape famine, social chaos, or environments contaminated with radioactivity.

Figure 1. A nuclear war between India and Pakistan or between India and China would have health and environmental consequences for the entire South Asia region, including neighboring countries Bangladesh and Nepal.

This nuclear war could cause immediate deaths from radiation exposure in neighboring countries--depending on meteorological conditions, which vary by season. Other impacts on the neighboring countries could arise from exposure to sub-lethal local fallout (increased long-term cancer risk), the disruption in cross-border trade of critical products such as food, floods from destroyed dams, and the movements of refugees across borders. Bangladesh would be particularly vulnerable to the consequences of a nuclear attack on Calcutta, and Nepal would suffer from attacks on northern Indian coastal cities.

Due to the relatively small size of the nuclear weapons used in this scenario, there would not be significant injection of radioactivity into the stratosphere. Hence this war would not contribute significantly to global radioactive fallout.

A China-India War

In this scenario the devastation on Indian cities by the higher yield Chinese weapons would be substantially greater. For example, a 150-kt attack on Bombay would be likely to cause between two and six million deaths [12]. Surface level nuclear explosions in this scenario would contaminate even larger areas of India than would be affected in an India-Pakistan exchange. Short term deaths in non-combatant countries such as Nepal and Bangladesh would also occur from nuclear attacks on Indian cities. For example, a surface burst explosion of 300 kt produces a 300-square-km fallout plume that delivers a 48-hour whole-body dose of 450 centiGray. This would be lethal to half the exposed adult population [13]. Depending on wind speed and direction, plumes could extend from explosions on Delhi and Calcutta into the territories of Nepal and Bangladesh respectively (e.g., with the predominant southwesterly winds which occur mid-year). By comparison, an estimated 53% of the total person-sievert exposure of radioactivity from Chernobyl affected those living in European countries outside the Soviet Union where the disaster occurred [14].

In this scenario, which involves weapons of 100 kt and larger, a proportion of the fallout would be injected into the stratosphere and hence circulate the globe and even cross the hemispheres. The global external gamma ray dose was estimated to peak at 4.6 milliGray (mGy) (at latitude 20 to 40 degrees North) in the Northern Hemisphere and 0.003 mGy (at latitude 30 to 50 degrees South) in the Southern Hemisphere. These levels of radiation would be expected to cause 230 fatal cancers per million population in the latitude bands of the Northern Hemisphere and 0.2 in the Southern Hemisphere. For the 20 to 40 degree North latitude, with a population of approximately 2.5 billion people, there would be an estimated 0.6 million radiation-induced cancer deaths. However, only around 12% of this dose would be delivered in the first 20 years, with the rest being delivered over thousands of years (based on the experience of atmospheric tests and the importance of carbon-14 as a radionuclide from these explosions [5]).

These levels of global fallout would only be marginally increased if Chinese weapons vaporised the contents of all India’s 10 nuclear reactors (i.e., adding an estimated 1.5 mGy to gamma ray doses from lower latitude Northern Hemisphere fallout). Bombing nuclear reactors, however, would dramatically increase the area contaminated with hazardous local fallout within the attacked country. For example, the explosion of a one-megaton bomb on a one-gigawatt reactor has been estimated to cause a fallout plume delivering total external gamma-ray doses of 100 centiGray per year around 530 km long and up to 70 km wide [4].

Discussion

This analysis indicates that plausible types of nuclear wars involving Pakistan, India, and China would have catastrophic impacts on these countries that would rival the previous worst disasters they have experienced. These include the 1876-1877 famine in India that affected 20 million and killed 3.5 million [15] and the 1958-1961 famine in China that caused an estimated 30 million premature deaths [16].

The global fallout distribution model used in this analysis has a number of limitations, including being based on limited data on Northern Hemisphere explosions in mid-latitudes [4]. The assumptions that there would be no weathering and no sheltering lead to an over-estimation of the exposure level since weathering is important in most environments and a majority of humans spend most of their lives indoors. These estimates of radiation exposure are probably conservative, however, since the effects of internal radiation dosage are not included and since these would probably be more important than external radiation in the long term [7]. Moreover, low-level radiation exposure might be significantly more hazardous than the estimate used in this analysis [17,18].

If the nuclear arsenals of these countries increase in size and in average weapon yield in the future, then multiple attacks on cities would become more likely in future war scenarios. This would further increase the risk of firestorms in cities suffering nuclear attack, which would increase the probability of toxic and radioactive debris reaching adjacent countries. It would also pose greater risks of regional climatic disturbances arising from nuclear war.

Adverse economic effects on neighboring countries would arise from disruption in cross-border trade, floods from destroyed dams, and the movements of refugees across borders. These impacts could be further exacerbated if there were cross-border radioactive contamination of primary agricultural products produced for export. Such impacts could damage trade for many years into the post-war period.

The use of weapons of mass destruction is the very worst way for nations to solve international disputes. Moreover, most forms of nuclear weapons use are likely to be illegal under international law [19] and damage to non-combatant countries in war breaches international law [20]. There is an urgent need for nuclear disarmament to lower the risk of such catastrophic nuclear wars. Progress toward disarmament is unlikely, however, without strong leadership by the United States and Russia towards a verifiable and enforceable Nuclear Weapons Convention [21].

References

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NW is a public health physician and an independent consultant to health organizations in Wellington, New Zealand.
Address correspondence to Nicholas Wilson, FAFPHM, 367A Karori Rd, Karori, Wellington, NZ; e-mail: nwilson@actrix.gen.nz.

© Copyright 1999 Medicine & Global Survival

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