International Day against Nuclear Tests

Since nuclear weapons testing began 80 years ago, over 2,000 have taken place. On the International Day against Nuclear Tests (IDANT), the   United Nations Secretary-General antonio Guterres calls on all States to ratify the Comprehensive Nuclear-Test-Ban Treaty. Its entry into force is more urgent than ever. “Now is the time to silence the bombs before they speak again.”

2025 Conference on Facilitating the Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty United Nations, New York;   The 14th Conference on Facilitating Entry into Force of the Comprehensive Nuclear-Test-Ban Treaty (Article XIV Conference) will take place at the United Nations in New York on Friday, 26 September 2025. Conference Material Draft Rules of Procedure (CTBT-Art.XIV/2025/1) English | Arabic | Chinese | French | Russian | Spanish Draft Provisional Agenda (CTBT-Art.XIV/2025/2) English | Arabic | Chinese | French | Russian | Spanish Information for participants: Note by the Secretariat (CTBT-Art.XIV-2025-INF.1) English Information for non-governmental organizations: Note by the Secretariat (CTBT-Art.XIV-2025-INF.2) English

As we observe the International Day against Nuclear Tests , we are also approaching another milestone. In 2026, we will mark 30 years since Comprehensive Nuclear Test-Ban Treaty was opened for signature . Anniversaries invite reflection, not only on what has been achieved but also on the work that lies ahead. Our Treaty has already had a profound impact. Nuclear test explosions have become extremely rare, and the verification regime operates with global reach and trust. We look forward to the day when Treaty enters into force, enabling all elements of the verification regime to be deployed. Achieving this will require the remaining States to take the final step . They have the opportunity to help complete what was started almost three decades ago. Their decision to ratify the Treaty would reinforce a commitment that has already proved its worth and support a system that benefits every region. This International Day is a reminder that the absence of nuclear test explosions is not a ma...

Today’s international climate is marked by heightened tensions and evolving geopolitical dynamics. However, the record leaves little room for doubt: testing has come to an almost complete halt, and States continue to support and use the verification system . This reflects a near-universal view that nuclear testing has no place in the twenty-first century . The International Day againts Nuclear Tests (IDANT) reminds us that change happens when people understand why it matters. Communities affected by past tests carry voices that deserve to be heard. Diplomats, scientists, educators and youth advocates help translate remembrance into prevention. Their work strengthens a culture of responsibility that maintains the silence we expect from test sites across the world.

The success of the Comprehensive Nuclear-Test-ban Treaty rests on science in the service of diplomacy. Its International Monitoring System (IMS) , already operating with more than 300 stations and laboratories in over 90 countries, uses seismic, hydroacoustic, infrasound and radionuclide technologies to detect any nuclear explosion . Data from this network flow to the International Data Centre in Vienna, where they are processed around the clock and made available to all signatory States. This transparency builds confidence. All States rely on the same objective information to assess adherence to the Treaty and to determine whether a nuclear test has taken place. Even countries that have not yet ratified the Treaty host facilities and benefit from the data. That participation reflects the value and credibility that nations place in a system built through global cooperation. Those benefits extend well beyond peace and security: IMS data contribute to tsunami warning systems, support...

Before the Comprehensive Nuclear-Test-ban Treaty (CTBT) was opened for signature, more than 2,000 nuclear test explosions had been conducted worldwide. Since 1996, that number has fallen to fewer than a dozen. This dramatic decline is no accident. It reflects the strength of the norm created by our Treaty and the value that the international community places on preventing any return to testing . The Treaty is already a proven success. It has brought almost all nuclear testing to an end, placing powerful constraints on the development of new nuclear weapons and the advancement of existing designs , while fostering a strong international expectation that testing belongs in the past . Entry into force will build upon this, giving us the full range of verification measures , including on-site inspections , to further reinforce what has already been achieved.

Nearly three decades ago, the world took decisive steps to bring nuclear test explosions to an end . Those actions changed the course of history. Where once the ground shook with alarming regularity, today such events are rare, a testament to the strength of our collective resolve. On August 29th , the International Day against Nuclear Tests (IDANT), we  reaffirm our commitment to placing non-proliferation and disarmament first , and to ensuring that no person ever again lives in the shadow of a nuclear explosion. We will never forget standing at ground zero in Semipalatinsk, Kazakhstan – a site scarred by more than 450 nuclear tests – the closure of which we also commemorate on this day. We felt the full weight of that history, a sobering reminder of what the international community must never allow to happen again. At the height of the cold war, such tests occurred almost weekly. They were not only a grave risk to global peace and security but also had a lasting impact on publ...

The U.S. conducts some of its most sensitive nuclear weapons research in a laboratory deep underground in Nevada. NPR was recently given a tour.  National Nuclear Security Administration/Nevada National Security Site The US conducts some of its most sensitive nuclear weapons research in a laboratory deep underground in Nevada. NPR was recently given a tour. PODCAST : Step inside the secret lab where America tests its nuke. In the middle of a dry lakebed northwest of Las Vegas sits a lone section of a bridge, its steel girders bent like spaghetti. Nearby are other oddities — a massive bank vault with no bank for miles; the entrance of an underground parking garage with no lower levels; and domes of rebar and concrete that have been ripped open, leaving their insides exposed to the desert sky. A half-mile from here, on the morning of May 8, 1953, an Air Force bomber dropped a Mk-6D nuclear bomb from a height of 19,000 feet above the desert floor. It exploded with a yield of 27 kil...

  Nuclear testing harms the environment , undermines economic development, and has devastating effects on people’s lives and health . It is a relic of another age that has no place in the 21st century. “ My message to leaders is simple: stop playing with fire. Now is the time to silence the bombs before they speak again, ” said UN Secretary-General ‌António Guterres on Friday's August 29th ,observance of the  International Day against Nuclear Tests .

The second phase of the Youth Leader Fund for a World without Nuclear Weapons (YLF) has officially begun! Following a high-level launch event at the Permanent Mission of Japan to the United Nations, the new chapter of this programme kicked off with an informal online gathering, where the new cohort met each other and connected with past YLF participants to hear about their experiences. This marks the start of a four-month online training component, where participants will dive into topics like: The human cost of nuclear weapons, Leadership and negotiation, The UN’s role in nuclear disarmament, Gender, youth and disarmament, Storytelling and journalism. ...And so much more! Stay tuned for more updates from YLF Phase II!

  On August 12th, we’re gathering at Expo 2025 Osaka for an intergenerational dialogue exploring the role of art and storytelling to preserve the legacy of the consequences of nuclear weapons. 📍 UN Pavilion Amphitheatre 🕑 14:00–15:30 JST (session in Japanese) Expo admission ticket required for site entry. Join UNODA x 1FUTURE at the Osaka World Expo 2025!