Most countries are parties to instruments of international humanitarian law such as the Geneva Conventions, the Biological Weapons Convention, and the Chemical Weapons Convention. International humanitarian law seeks to address the humanitarian problems that arise, directly or indirectly, from armed conflict (whether or not the conflicts are international). It limits combatants' ability to utilize certain methods and weapons of war, thus protecting civilians and their property from harm. Many nations that have chosen to become parties to instruments of international humanitarian law have done so for one of two reasons: They favor peace in general, or they fear large, catastrophic events such as nuclear detonations.
Several basic principles underlie international humanitarian law. One is the principle of distinction, which requires militaries to target only combatants, never civilians. But a nuclear attack, even if it were theoretically aimed at an exclusively military objective, would carry severe consequences for public health. It would raise civilians' risk of developing degenerative diseases—notably cancer of the skin, liver, kidneys, stomach, and lungs. The most extreme effects, sadly, would appear in the most vulnerable segments of the population: children and the elderly. The health risks would extend to food, which would be harmful to people in the country affected and could not be exported, worsening the economic disaster that would afflict any country where a detonation occurred. So a nation could be left with little edible food; few financial resources; and a greatly reduced population. Any state affected in this way would have no choice but to declare itself a radiological emergency zone and ask for international support to help protect its population. Meanwhile, civilians would likely mount an exodus toward non-contaminated or less contaminated territory, even if this meant crossing borders. (This did not occur in the aftermath of the Hiroshima and Nagasaki bombings, largely because at the time there was little awareness about the health effects of high radiation doses.)
A second principle is that of proportionality, which prohibits attacks causing fatalities, injuries, and property damage that are excessive in relation to the concrete military advantage that is anticipated. A nuclear explosion inarguably violates this principle, for it unavoidably affects very large territories and very large populations. A third principle, expressed in instruments such as the Hague Convention for the Protection of Cultural Property, prohibits attacks on sites of cultural importance. But nuclear detonations are indiscriminate, and it is hardly possible to carry out a nuclear attack without destroying sites of cultural importance. Civilians in affected areas, suffering from enormous casualties, continuing health risks, and property destruction, would only be more likely to flee if they saw their cultural heritage destroyed as well.
Utterly vulnerable. In the event of a nuclear detonation, nations will be best equipped to respond to and mitigate the catastrophe if they possess certain basic elements of infrastructure. These include, at a minimum, a national architecture for radiation detection, a radiological emergency response center, a suitable communications center, a hospital specializing in radiological emergencies, a center for the decontamination of people, and adequately trained personnel, including civil defense and radiological emergency brigades. In countries where radiological accidents have occurred, the effects have often been mitigated in short order thanks to adequate national response capacity. However, countries with few economic resources in the first place have little response capacity.
After a nuclear detonation, the poorest countries would be utterly vulnerable: They lack the necessary infrastructure and the qualified personnel to respond effectively. The humanitarian effects of a detonation in such a country, both immediately and over the medium and long terms, would be incalculable. In middle-income countries, the consequences would be somewhat less but still catastrophic. Not even developed countries, where state-of-the-art technology is readily available, would be prepared to deal adequately with the consequences of a nuclear explosion. In fact, no one in the world is prepared to face a disaster on the scale of a nuclear detonation.
Nuclear weapons are frighteningly destructive in both humanitarian and environmental terms, and any individual or group of individuals who ordered their use would arguably be guilty of a crime against humanity. The world must continue to work for the day when nuclear weapons are abolished.