Resolution 3472 B (1975) of the United Nations General Assembly (UNGA) defines a NWFZ as:
“...any zone recognized as such by the General Assembly of the United Nations, which any group of States, in the free exercises of their sovereignty, has established by virtue of a treaty or convention whereby:
- The statute of total absence of nuclear weapons to which the zone shall be subject, including the procedure for the delimitation of the zone, is defined;
- An international system of verification and control is established to guarantee compliance with the obligations deriving from that statute."
The States that make up a NWFZ, in the exercise of their sovereignty, commit themselves to prohibit, within their respective territories, the research, design, development, testing, acquisition, deployment, and possession of nuclear weapons.
Resolution 3472 B also includes a definition of the principal obligations of the nuclear-weapon States towards nuclear-weapon-free zones and towards the States included therein:
“2. In every case of a nuclear-weapon-free zone that has been recognized as such by the General Assembly, all nuclear-weapon States shall undertake or reaffirm, in a solemn international instrument having full legally binding force, such as a treaty, a convention or a protocol, the following obligations:
- To respect in all its parts the statute of total absence of nuclear weapons defined in the treaty or convention which serves as the constitutive instrument of the zone;
- To refrain from contributing in any way to the performance in the territories forming part of the zone of acts which involve a violation of the aforesaid treaty or convention;
- To refrain from using or threatening to use nuclear weapons against the States included in the zone.”
The UN Disarmament Commission in its report of April 30, 1999, recommended a set of principles and guidelines for the establishment of a nuclear-weapon-free zone, which included, inter alia:
- Nuclear-weapon-free zones should be established on the basis of arrangements freely arrived at among the States of the region concerned.
- The initiative to establish a nuclear-weapon-free zone should emanate exclusively from States within the region concerned and be pursued by all States of that region.
- In cases where consensus exists on the goal to establish a nuclear-weapon-free zone in a given region, efforts exerted by the States of the region concerned aimed at the establishment of such a zone should be encouraged and supported by the international community. Assistance should be provided, as appropriate, including through the essential role of the United Nations, to the States of the region concerned in their efforts to establish a nuclear-weapon-free zone.
- All the States of the region concerned should participate in the negotiations on and the establishment of such a zone on the basis of arrangements freely arrived at among the States of the region concerned.
- The status of a nuclear-weapon-free zone should be respected by all States parties to the treaty establishing the zone as well as by States outside the region, including all States whose cooperation and support are essential for the maximum effectiveness of such a zone, namely, the nuclear weapon States and, if there are any, States with territory or that are internationally responsible for territories situated within the zone concerned.
- The nuclear-weapon States should be consulted during the negotiations of each treaty and its relevant protocol(s) establishing a nuclear-weapon-free zone in order to facilitate their signature to and ratification of the relevant protocol(s) to the treaty, through which they undertake legally binding commitments to the status of the zone and not to use or threaten to use nuclear weapons against States parties to the treaty.
- If there are any States with territory or that are internationally responsible for territories within the zone concerned, these States should be consulted during the negotiations of each treaty and its relevant protocols establishing a nuclear-weapon-free zone with a view to facilitating their signature and ratification of the relevant protocol(s) to the treaty.
- Every treaty through which a nuclear-weapon-free zone (NWFZ) is established should provide for the effective prohibition of the development, manufacturing, control, possession, testing, stationing or transporting by the States parties to the treaty of any type of nuclear explosive device for any purpose, and should stipulate that States parties to the treaty do not permit the stationing of any nuclear explosive devices by any other State within the zone.
- Every treaty through which a nuclear-weapon-free zone (NWFZ) is established should provide for the effective verification of compliance with the commitments made by the parties to the treaty, inter alia, through the application of full-scope IAEA safeguards to all nuclear activities in the zone.
- A nuclear-weapon-free zone (NWFZ) should not prevent the use of nuclear science and technology for peaceful purposes and could also promote, if provided for in the treaties establishing such zones, bilateral, regional, and international cooperation for the peaceful use of nuclear energy in the zone, in support of socio-economic, scientific, and technological development of the States parties.
The opening for signature in 1967 of the Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco) established the first NWFZ in a permanently populated territory of the planet.
The Latin American and Caribbean initiative would go on to inspire the establishment of four other NWFZs: South Pacific (Treaty of Rarotonga, 1985); Southeast Asia (Treaty of Bangkok, 1995); Africa (Treaty of Pelindaba, 1996); Central Asia (Treaty of Central Asia, 2006) and the territory of Mongolia, which in the year 2000 gained international recognition as a State free of nuclear weapons (UNGA Resolution 55/335).
• Treaty of Tlatelolco: Establishes the NWFZ of Latin America and the Caribbean. It was opened for signature on 14 February 1967 and entered into force on 22 April 1969. It has been ratified by all the 33 states of the region: Antigua & Barbados, Argentina, The Bahamas, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominica, Ecuador, El Salvador, Granada, Guatemala, Guyana, Haití, Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Dominican Republic, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Suriname, Trinidad and Tobago, Uruguay and Venezuela. The Treaty of Tlatelolco contains two Additional Protocols. Additional Protocol I is aimed at extraterritorial States which, de jure or de facto, have territories under their jurisdiction in the Treaty´s Zone of Application. It has been signed and ratified by The United States, France, The Netherlands, and the United Kingdom. As for Additional Protocol II, it is aimed at Nuclear Weapons States. It has been signed and ratified by China, the United States, France, the United Kingdom, and Russia.
• Treaty of Rarotonga: Establishes a NWFZ in the South Pacific. It was opened for signature in Rarotonga (Cook Islands), on 6 August 1985 and entered into force on 11 December 1986. It has 16 states parties: Australia, Cook Islands, Fiji, Kiribati, Marshall Islands, the Federated States of Micronesia, Nauru, New Zealand, Niue, Palau, Papua New Guinea, Solomon Islands, Tonga, Tuvalu, Vanuatu, and Western Samoa. The treaty contains three Protocols, which have been signed and ratified by the Nuclear Weapon States, with the exception of the United States, which has not yet ratified.
• Treaty of Bangkok: Establishes the NWFZ of Southeast Asia. It was opened for signature on 15 December 1995 by the 10 Member States of the Association of Southeast Asian Nations. It entered into force on 27 March 1997. It has been ratified by all the states of the Zone: Brunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. To date, none of the Nuclear Weapons States have signed the Treaty´s Protocol.
• Treaty of Pelindaba: Establishes the NWFZ of the African continent. It opened for signature on 12 April 1996 in Cairo, Egypt. The Treaty of Pelindaba has been signed by 51 States: Argelia, Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cabo Verde, Central African Republic, Chad, Comoros, Congo, Ivory Coast, Djibouti, Egypt, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenia, Lesotho, Liberia, Libya, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Democratic Republic of Congo, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leona, Somalia, South Africa, Sudan, Swaziland, Tanzania, Togo, Tunisia, Uganda, Zambia and Zimbabwe. However, 15 States have not ratified. The Treaty has three Additional Protocols. The five Nuclear Weapon States have signed protocols I and II; the United States has not ratified any of them. France ratified Protocol III and Spain has not signed it.
• Treaty of Central Asia: It was signed on 8 September 2006 and entered into force on 21 March 2009. This treaty was ratified by the five states of the region, all belonging to the now extinct Union of Soviet Socialist Republics: Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. It is the first NWFZ established in the northern hemisphere of the planet. In May of 2015, all five Nuclear Weapon States simultaneously signed the Protocol to this Treaty.
• The Nuclear Weapon Free State of Mongolia: the continuing effort of Mongolia and the work carried by during different sessions of the United Nations Disarmament Commission resulted in Resolution 53/77 D, adopted at the 53rd Session of the General Assembly on 4 December 1998, which welcomed Mongolia´s decision to declare its territory free of nuclear weapons.
The five NWFZs and Mongolia make up a total of 115 States Parties and signatories, encompassing more than 50% of the planet´s surface.
There are other international instruments which also address the military denuclearization of certain geographic zones: