The nuclear arsenals of Britain, France, China, Israel, India, and Pakistan are thought to lie in the range of ~100 to 300 warheads each. Although the use of these weapons by any of these countries could produce a regional, and likely global, disaster, India and Pakistan are of special concern because of a long history of military clashes including serious recent ones, lack of progress in resolving territorial issues, densely populated urban areas, and ongoing rapid expansion of their respective nuclear arsenals. Here, we examine the possible repercussions of a nuclear war between India and Pakistan circa 2025 in which cities are one class of target, either by direct or collateral targeting. These repercussions have not been investigated previously. Because of the near-term regional effects of nuclear blast, thermal radiation, and prompt nuclear radiation, we find that perhaps for the first time in human history, the fatalities in a regional war could double the yearly natural global death rate. Moreover, the environmental stresses related to climate changes caused by smoke produced from burning cities could lead to widespread starvation and ecosystem disruption far outside of the war zone itself.
The United States and Russia account for around 93% of the world’s estimated 13,900 nuclear weapons. Seven other nuclear-armed nations are not bound by treaties that require them to divulge information, such as the number of strategic launchers and the number of warheads deployed on missiles, allowing estimates of the numbers of nuclear warheads and yields in their arsenals, but between them, the seven nations may now hold a total of 1200 warheads. India’s and Pakistan’s nuclear forces in 2019 each may contain 140 to 150 warheads, with a possible expansion to 200 to 250 warheads in each country by 2025. Britain (~215), France (~300), China (~270), and Israel (~80) have a similar number of weapons but have been maintaining relatively constant arsenals. Estimates of the numbers of warheads possessed by India and Pakistan are based on the capacity of delivery systems that can be observed from remote sensing, rather than on the amount of enriched uranium and plutonium fuel that the countries may have produced.