Comprehensive Nuclear-Test-Ban Treaty — international treaty to ban nuclear explosions
The CTBT established a global norm against nuclear testing, though it has not entered into force due to non-ratification by key states.
Key Facts
- Adoption date
- 10 September 1996
- States signed / ratified
- 187 signed, 178 ratified (as of 2024)
- Annex 2 non-ratifiers
- 9 states including US, China, Russia, India, Pakistan, North Korea
- Nuclear tests since 1996
- 16, all by non-signatory states
- IMS monitoring stations planned
- 321 stations and 16 laboratories across 89 countries
- Nuclear tests 1945–1996
- Over 2,000
By the Numbers
Location
Cause → Event → Consequence
Over 2,000 nuclear test explosions conducted between 1945 and 1996, primarily by the United States and Soviet Union, prompted international efforts to curb nuclear proliferation. Building on the 1963 Partial Nuclear Test Ban Treaty and the 1968 NPT, negotiations in the Conference on Disarmament during 1995–96 sought a comprehensive ban on all nuclear explosions.
The UN General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty on 10 September 1996, prohibiting all nuclear weapons test explosions and other nuclear explosions in any environment, whether civilian or military. The treaty opened for signature and was first signed by the United States, while establishing a monitoring body and an International Monitoring System of 321 stations across 89 countries.
Despite not entering into force due to nine Annex 2 states failing to ratify—including the US, China, Russia, India, Pakistan, and North Korea—the treaty established a widely observed norm against nuclear testing. Only sixteen nuclear tests have been conducted since 1996, all by non-signatories. Russia withdrew its ratification in 2023, and the US Senate had rejected ratification in 1999.
Political Outcome
Adopted by the UN General Assembly but not in force; 178 states ratified, nine Annex 2 states (including US, China, Russia, India, Pakistan, North Korea) have not ratified. Russia withdrew ratification in 2023.