The Use of Nuclear Weapons
Adopted by the Council on Oct. 23, 2025
Effective Oct. 23, 2025
The American Physical Society supports measures to minimize the risk that nuclear weapons will be used. One nuclear detonation can destroy an entire city; hundreds or thousands of detonations are an existential threat to civilization through millions of immediate deaths and injury, destruction of key infrastructure, radioactive fallout, and potentially catastrophic climate impacts.1 Any use of nuclear weapons, even a single nuclear weapon during a conventional conflict, would bring with it substantial risk of escalation to general nuclear war. Although nuclear weapons have only been used twice in warfare, nuclear weapons remain a critical issue. More than 10,000 remain in nine countries today, and nearly all are investing considerable resources in upgrading and modernizing their nuclear arsenals.
The United States should enact policies that reduce the role that nuclear weapons play in national security policy and reduce the number of weapons deployed and stockpiled. In keeping with their obligations under the Non-proliferation Treaty, the United States and all other parties should vigorously pursue the goal of nuclear disarmament and the prohibition of nuclear weapons. The United States should seek international treaties and other agreements that limit or prohibit the development, acquisition, testing, deployment, threat of use, or use of nuclear weapons and nonproliferation agreements and measures that limit or prohibit the spread of nuclear weapons and related technologies. The United States should invest in the development of verification technologies that build confidence in compliance with arms control and nonproliferation agreements and measures that protect nuclear materials from theft or diversion and prevent nuclear terrorism.
Nuclear war would produce an enormous number of direct casualties from blast and fire, as well as longer-term deaths from radiation-induced illness. It could depress economic activity and food production, leading to widespread famine, disease, and conflict. A 1979 report by the Congressional Office of Technology Assessment estimated that general nuclear war between the US and Soviet Union would kill between 28-88% of Americans and 22-50% of Soviets.
Table 0-1, The Effects of Nuclear War, May 1979, Congressional Office of Technology Assessment
A 1980s independent assessment of civilian casualties from a Soviet attack on U.S. strategic military targets estimated that direct effects of these weapons would have resulted in killing or seriously injuring 23-45 million, and an additional 2-20 million might have developed radiation-caused cancers. A similar attack by the United States on the Soviet Union could have killed or injured a total of 25-54 million people in the short term with an additional 2-14 million suffering radiation-induced cancers in the longer term. Direct attacks on urban areas could have caused twice this number of lethal and non-lethal injuries. Civilian Casualties from “Limited” Nuclear Attacks on the USSR. Barbara G. Levi, Frank N. Von Hippel, and William H. Daugherty. Even limited nuclear attacks have the potential to significantly disrupt economic systems through the collapse of transportation, energy production, trade, and modern agriculture, potentially for decades. A 1980s analysis based on Federal Emergency Management Agency models concluded that an attack on 71 US cities plus 200-300 weapons on industrial targets would induce economic collapse with no recovery, and a smaller attack could leave the US at one-third GDP or less for decades. Nuclear Crash: The U.S. Economy After Small Nuclear Attacks. M. Anjali Sastry, Joseph J. Romm, and Kosta Tsipis., Massachusetts Institute of Technology report, June 1, 1987.
These estimates did not include the effects of nuclear war on the climate. The cooling of the earth’s surface due to an increase of persistent sun-blocking soot in the upper atmosphere from a major nuclear exchange could result in the decline of average surface air temperatures in important regions, resulting in suppressed terrestrial and aquatic food production, potentially triggering widespread famine and disease. Even a limited nuclear exchange risks serious climate effects through soot produced by the burning of urban centers, should large amounts of soot be lofted into the upper atmosphere, spread, and persist. Xia et al. find in a nuclear war between India and Pakistan attacking urban centers that “more than 2 billion people could die from nuclear war between India and Pakistan, and more than 5 billion could die from a war between the United States and Russia.” Xia, L., Robock, A., Scherrer, K. et al. Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection. Nat Food 3, 586–596 (2022).