After Five Years, What Impact Has the Nuclear Ban Treaty Had on the World?

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On January 22, 2021, the Treaty on the Prohibition of Nuclear Weapons (TPNW) entered into force. The treaty is now signed, ratified, or acceded to by the majority of countries eligible to do so, demonstrating a global majority in favour of the most comprehensive nuclear weapons prohibition ever negotiated.

Significantly, since the TPNW became international law, it has played a dynamic role in the global nuclear weapons policy discourse. This article will look at five ways the TPNW has impacted nuclear disarmament in the last five years.

First, it has clarified and closed a longstanding legal gap on nuclear weapons, comprehensively prohibiting them as is the case with other weapons of mass destruction (biological and chemical weapons).

Before the UN General Assembly mandated negotiations of the TPNW, there was no single treaty universally outlawing nuclear weapons activities including their possession, development, production or use. Rooted in international humanitarian and human rights law, the TPNW is comprehensive in outlawing the development, testing, production, manufacture, stockpiling, possession, hosting, or acquisition of nuclear weapons. It provides a framework for countries that have nuclear weapons to either join the treaty and dismantle their arsenals under a plan agreed amongst states parties, or to dismantle their arsenals and join with International Atomic Energy Agency agreements in place to ensure there are no weapons-related activities remaining.

While the Non-Proliferation Treaty of 1968 prohibits new countries from manufacturing nuclear weapons, it does not impose a general ban on the use or possession of nuclear weapons for all its parties, and the various nuclear-weapon-free zone treaties adopted since 1967 prohibit nuclear weapons only within particular geographic regions. The TPNW filled this legal gap.

Second, the TPNW has enabled a broad understanding of the catastrophic humanitarian and environmental harm caused by nuclear weapons. The TPNW was born out of the deep concern of a majority of the world’s governments at the growing threat that nuclear weapons pose to human survival, the environment, socioeconomic development, the global economy, food security, and the health and welfare of current and future generations.

The TPNW has strengthened the nuclear taboo that developed from the knowledge of what happened at Hiroshima and Nagasaki, and of the catastrophic and long-lasting, intergenerational harm these weapons do to people.  The treaty has made humanitarian concerns the focus of efforts to advance nuclear disarmament, when previously such concerns were not prominent in international discussions, and it includes an obligation to provide victim assistance and environmental remediation for the people and places harmed by nuclear weapons use and testing. The TPNW is about protecting people.

Third, the TPNW has solidified the international consensus that nuclear threats are inadmissible. It is the first multilateral treaty to explicitly prohibit nuclear threats. Since the TPNW became international law, there have been several instances in which nuclear-armed countries have overtly threatened the use of nuclear weapons, and the TPNW has fostered collaborative responses that have been taken up even by countries that have not yet joined. Efforts, including a joint statement at the UN General Assembly 11th Special Session on Russian Aggression, by TPNW supporters resolutely rejecting Russian orders to raise the readiness levels of its nuclear forces, have highlighted the humanitarian consequences of nuclear weapons and the critical international treaties to constrain nuclear behaviour. Of these, the TPNW is the only treaty that “expressly prohibits any use or threat of use of nuclear weapons.” The Vienna Declaration, issued at the conclusion of the first TPNW Meeting of States Parties in 2022 also condemned unequivocally “any and all nuclear threats, whether they be explicit or implicit and irrespective of the circumstances.”

These efforts resonated in further condemnation of nuclear threats, including in the G20 Summit in Bali, in which G20 leaders, including nuclear-armed members, affirmed that "The threat of use or use of nuclear weapons is inadmissible," while then NATO Secretary General Jens Stoltenberg said “Any use of nuclear weapons is absolutely unacceptable.”  Other leaders, including Xi Jinping and Olaf Scholz have also condemned nuclear threats in similar language to that initially used by TPNW States Parties. 

Fourth, the concept of nuclear justice is now on the table across multiple nuclear disarmament forums. Prior to the TPNW’s entry into force, there were few opportunities for countries to discuss in a multilateral setting and in a focused way how to provide for victim assistance and environmental remediation where nuclear testing has taken place.

The TPNW has inspired action at the UN General Assembly, where, in 2023, Kiribati and Kazakhstan led a resolution encouraging all states to cooperate to provide victim assistance and environmental remediation, including, for those in a position to do so, through technical and financial assistance. It also urges states that have used or tested nuclear weapons to share technical and scientific information on their consequences with affected states, and acknowledges the special responsibility of these states to address harm. Only four states voted against the resolution: France, North Korea, Russia, and the United Kingdom, while 171 countries voted in favour and six abstained.

Nuclear justice issues are also under discussion outside of the more traditional nuclear disarmament forums, including in the UN Human Rights Council which released a report in 2024 on “Addressing the challenges and barriers to the full realization and enjoyment of the human rights of the people of the Marshall Islands, stemming from the State’s nuclear legacy.” While the report specifically addresses the human rights implications of US nuclear testing in the Marshall Islands, it also draws attention to the ongoing consequences of nuclear weapons and human rights violations due to nuclear testing in many other places.

Finally, the TPNW has inspired investors to take their money out of nuclear weapons. As public stigma against nuclear weapons grows, corporate involvement in nuclear weapons becomes more commercially risky. Banks, pension funds, and other financial institutions representing at least $4.7 trillion of global assets have refused to finance or seek profit from the companies involved in the nuclear weapons industry.

The TPNW has demonstrated the feasibility of nuclear disarmament at a time when the possibility of achieving a nuclear-weapon-free world seemed remote. The treaty has provided confidence to governments and the public that progress can be achieved towards a world free of nuclear weapons.

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Susi Snyder is the Director of Programmes for the International Campaign to Abolish Nuclear Weapons (ICAN), where she facilitates the design and delivery of ICAN’s strategic objectives, including divestment initiatives and engagement with the financial sector. Susi previously served as ICAN’s president, including when the organisation won the 2017 Nobel Peace Prize. For more than a decade, she has coordinated Don’t Bank on the Bomb, a leading effort to end financial support for companies involved in nuclear weapons production. Ms Snyder is a Foreign Policy Interrupted/Bard College Fellow (2020) and a Nuclear Free Future Award Laureate (2016)..