On 8 – 9 December 2014, states meeting in Vienna to discuss the humanitarian impact of nuclear weapons will have the opportunity to voice their views on the legality of nuclear weapons under existing international law.

The legality of nuclear weapons is a controversial and politically sensitive issue. The questions at the core of the legal debate are whether (and if so, under what circumstances) it is legal to use nuclear weapons, and, connected to this, whether it is legal to threaten the use of nuclear weapons and to engage in other activities involving nuclear weapons, such as the development, testing, manufacture, possession, emplacement, deployment and transfer of nuclear weapons.

This paper provides a brief overview of some relevant legal rules and principles, with a focus on nuclear disarmament, and rules for the protection of the human person and of the environment. A number of existing instruments already severely restrict activities involving nuclear weapons, and all states remain under a legal obligation to eliminate nuclear weapons. In light of the potentially catastrophic humanitarian and environmental consequences of a nuclear weapon detonation, nuclear weapons appear difficult to reconcile with key principles of environmental law as they have evolved in recent decades. There are also strong indications that nuclear weapons could not be used in compliance with international legal rules for the protection of the human person.

The horrific suffering and the vast scale of devastation they can cause, as well as the difficulty of containing their effects in space and time mean that nuclear weapons threaten sustainable development and are contrary to principles of humanity and other values that provide the foundation of the international legal order. Other weapons of mass destruction (WMD) have been outlawed because they are considered repugnant to the conscience of humankind. No treaty prohibits nuclear weapons unequivocally and comprehensively. Safeguarding the human health and human rights of present and future generations is the concern of all states. To this end, a treaty banning nuclear weapons is urgently needed.

Download the briefing paper

 The effects of nuclear weapons under international law

December 2014

Briefing paper