The obligation to eliminate nuclear weapons
Once again, the conduct in 2022 of all the nuclear-armed states was manifestly incompatible with the TPNW’s obligation to eliminate nuclear weapons. There was no evidence that any of the nuclear-armed states have the will purposefully to pursue nuclear disarmament.

The five-nuclear weapon states parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT)–China, France, Russia, the United Kingdom, and the United States–therefore also continued to fail to comply with their existing obligation under Article VI of the NPT to ‘pursue negotiations in good faith’ on nuclear disarmament.
All of the nuclear-armed states have a declared commitment to nuclear disarmament and the pursuit of a world free of nuclear weapons.1 Their stance, however, is that the prevailing security environment is not conducive to further reductions. Ultimately, they reject the commitment to actually achieve nuclear disarmament (and by extension the objective of both the NPT and the TPNW), in favour of an open-ended commitment to work towards it, seemingly in perpetuity. Their focus is not on nuclear disarmament, but on risk reduction, nonproliferation, counter-proliferation, and arms control measures, where the underlying logic is that nuclear deterrence as a system will continue.
According to the Federation of American Scientists (FAS), the number of nuclear weapons in the world peaked in 1986 at around 70,300 warheads. That number has since been reduced by 82%, to the estimated 12,512 warheads at the beginning of 2023. These reductions were mainly done in the 1990s and early 2000s and predominantly because of cuts in the massive US and Russian arsenals.
Each year since then, including in 2022, the total number of warheads in the world has decreased slightly, but this is only still true because Russia and the United States each year dismantle a small number of their older nuclear warheads that have been retired from service.
The number of nuclear warheads dismantled each year now appears to be decreasing, as illustrated by the data on US nuclear warhead dismantlements in the figure below. Russia does not release information on dismantlements. The Nuclear Weapons Ban Monitor in collaboration with the Federation of American Scientists estimate that Russia during the course of 2022 dismantled approximately 100 warheads, and the United States 184 warheads. As of January 2023, Russia had an estimated 1,400 retired warheads awaiting dismantlement, and the United States 1,512 warheads. Dismantlement of Cold War-era retired nuclear weapons will soon be exhausted as a course of action to reduce the global nuclear arsenal. No further progress in nuclear disarmament will then be in sight, unless nuclear-armed states can accept that their current usable arsenals are not indispensable.
Tenth NPT Review Conference
The Tenth Review Conference of the NPT in August 2022 ended in failure to agree on the text of a draft outcome document. Russia’s objection to wording on nuclear safety at Ukraine’s Zaporizhzhia nuclear power plant, occupied by its forces since March 2022, meant no consensus could be reached. However, the final text circulated for approval contained no substantive progress on nuclear disarmament issues. As Ray Acheson of Reaching Critical Will concluded: ‘Russia was fully aligned with the other NPT nuclear-armed states in actively preventing any meaningful commitment to advance nuclear disarmament, stop nuclear threats, or reduce nuclear risks from being included in the outcome document.’1 The final session of the Review Conference therefore saw expressions of concern at the lack of ambition on disarmament in the outcome document, a weakening of language agreed at previous review conferences, and resistance from the nuclear-armed states to greater accountability for their disarmament obligations. A number of states parties and signatories to the TPNW said in a joint statement that: ‘While the document before us points to the urgency to act upon the unacceptable humanitarian consequences and risks of nuclear weapons, it then falls dramatically short of advancing nuclear disarmament and actually implementing Article VI of the NPT or even concretely addressing the serious risks inherent in nuclear weapons.’2
The failure at the NPT Review Conference reinforced the case for the TPNW. The Austrian delegation to the NPT noted that: ‘The last four weeks have shown us again how the NPT primarily cements the status quo or even backtracks. No matter the existing obligations and commitments, the Treaty does little in real life to move us forward on nuclear disarmament … we see once again how little is possible.’ The status quo, Austria said, ‘is simply not an option’, calling on ‘all states who want to achieve actual progress on Article VI of the NPT to join the TPNW.’3
In advance of the NPT Review Conference, Ban Ki-moon—former UN Secretary-General and now a deputy chair of The Elders—had warned against a growing fatalism about nuclear disarmament and said that the P5 states needed to ‘step up at the review conference and show the world they are serious about peace and disarmament’. He also said: ‘the need for new ideas and fresh commitment is paramount. Yet there is a striking contrast between the low expectations for and gloom surrounding the NPT Review Conference and the energy that was visible at the first meeting of states parties to the [TPNW].’ ‘If nuclear states want to be taken seriously, they need to respond with the same energy and purpose as the TPNW states in advancing arms control and disarmament’, said Ki-moon.4
First Meeting of States Parties to the TPNW
‘We have no illusions about the challenges and obstacles that lie before us in realizing the aims of this Treaty’ the states parties said in the final paragraph of the Declaration they adopted at the First Meeting of States Parties to the TPNW (1MSP) in Vienna in June 2022. ‘But we move ahead with optimism and resolve. In the face of the catastrophic risks posed by nuclear weapons and in the interest of the very survival of humanity, we cannot do otherwise. We will take every path that is open to us, and work persistently to open those that are still closed. We will not rest until the last state has joined the Treaty, the last warhead has been dismantled and destroyed and nuclear weapons have been totally eliminated from the Earth.’5
The 1MSP also adopted the Vienna Action Plan, where, inter alia, the states parties resolved to pursue further discussions in the intersessional period on the ‘competent international authority or authorities (IA)(s)’ which they will designate to negotiate and verify the irreversible elimination of nuclear-weapons programmes of destroy-and-join states and join-and-destroy states (Action 15). They also agreed to designate contact points with regard to the designation of IA(s) (Action 16). New Zealand and Mexico were appointed co-chairs of an informal working group on the implementation of Article 4 of the TPNW, in particular with respect to the future designation of a competent international authority or authorities to oversee such work. Participation in the working group is open to all states parties. The 1MSP also decided to establish a Scientific Advisory Group, which will provide guidance for Treaty implementation, including on the disarmament and verification obligations in Article 4.
Meetings in the working group on Article 4 were expected to be held about once a month in 2023. In accordance with Article 4(2), the 1MSP set a ‘maximum upper limit’ of ten years for the destruction of a state party’s nuclear weapons and other nuclear explosive devices. In a single ten-year period, it might even be feasible to achieve elimination of even the largest nuclear-weapon stockpiles (i.e. those of the United States and Russia).6 The deadline of ten years is, however, renewable for a period of up to five years, upon request to the other states parties. The extension will be granted where the additional time is necessary to ‘overcome unexpected difficulties in the disarmament process’.
Some nuclear-armed states, umbrella states, and NATO continue to frame the TPNW as a call for ‘unilateral’ and ‘unverifiable’ disarmament. These claims are misleading. It is certainly possible for a nuclear-armed state to adhere to the Treaty and disarm without other nuclear-armed states doing the same, and it is important that such an option exists. (Indeed, many critics of the TPNW insist that, for example, North Korea should disarm unilaterally). Few would, however, expect the United States or Russia to do so, and nuclear-armed states may therefore of course also commit under the TPNW to eliminate their nuclear-weapons programme through bilateral or multilateral disarmament arrangements that provide for mutual elimination.
Nuclear disarmament verification
The TPNW is the first and only legally binding multilateral instrument that specifically provides for and requires verification of nuclear disarmament. No such requirement exists in the NPT. The TPNW is helping to create the conditions for nuclear disarmament by establishing a framework for verified and irreversible elimination of states’ nuclear-weapons programmes. The value of the TPNW as a contribution to disarmament goals should therefore be recognised even by those states not yet ready to adhere to the Treaty themselves.
Action 18 of the Vienna Action Plan committed states parties to ‘advancing and supporting progress on nuclear disarmament verification, while recognizing that verification is not an end in itself, nor a substitute for nuclear disarmament, but a positive enabler for progress on disarmament’. In addition, states parties resolved through Action 37 to cooperate with other international bodies, such as the International Atomic Energy Agency (IAEA) and the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), in order to enhance cooperation, including in the areas of nuclear safeguards and verification, with a view to enhance the complementarity between the TPNW, the NPT, and the Comprehensive Nuclear-Test-Ban Treaty (CTBT).
The complexity of verification of nuclear disarmament means that many years are likely to be required before TPNW states parties are in a collective position to adopt their approach. When any nuclear-armed state adheres to the TPNW, the general verification model will also need to be tailored to the particular circumstances of that state. The designation of the competent international authority (or authorities) will probably follow substantive progress on the model for verification. A 2022 report edited by Pavel Podvig and published by the UN Institute for Disarmament Research (UNIDIR) argues that, as a new paradigm, ‘the TPNW opens a new political and technical space for innovation and offers opportunities for a new generation of disarmament science researchers and disarmament practitioners from around the world with different kinds of skills to identify possible disarmament-verification measures that would be significantly different from those identified as part of the existing arms control experience’. That experience it described as ‘shaped by active suspicion and distrust of treaty partners and by national security imperatives to protect nuclear weapon information, arsenals, capabilities and policies’.7
In contrast, Podvig and his co-authors foresee that cooperation and transparency will have an important role to play in verification of nuclear disarmament under the TPNW, because a nuclear-armed state’s decision to relinquish nuclear weapons and join the TPNW would necessarily be accompanied by a deep transformation of the state and be a highly visible process, ‘where the disarming state would be actively seeking cooperation with the international community to demonstrate its commitment to the obligations it assumed by joining the Treaty.’8 This view of disarmament as a political process focused on cooperation, transparency, problem-solving, and consultation significantly expands the set of tools that can be used to verify compliance with the TPNW. It is therefore important to strengthen institutions that can turn this vision into reality, which is a challenging task considering the non-participation of or active opposition from nuclear-armed states. To overcome these obstacles, the UNDIR report recommends ‘building capacity and assembling a critical mass—economic, institutional, bureaucratic and maybe military as well—to support a world that does not rely on nuclear weapons.’8
This will be a long process, but the TPNW is assuredly one of its elements.
- In accordance with Article 4(6) of the TPNW, the states parties are explicitly obligated to designate a ‘competent international authority or authorities’ to negotiate and verify the irreversible elimination of nuclear weapons programmes.
- The TPNW provides two pathways to the future adherence of nuclear-armed states: one for so-called destroy-and-join states (‘Article 4(1) states’) and a second for so-called join-and-destroy states (‘Article 4(2) states’).
- Article 4(1) obligates each nuclear-armed state that destroys its nuclear weapons and eliminates its nuclear-weapons programme before adhering to the TPNW, to cooperate with the ‘competent international authority’ that states parties will designate to verify nuclear disarmament, in order to ascertain that its nuclear-weapon programme has been irreversibly eliminated.
- Article 4(2) obligates those nuclear-armed states that decide to adhere to the Treaty before completing nuclear disarmament, to immediately remove the weapons or devices from operational status and to destroy them as soon as possible but not later than the deadline of ten years determined by the First Meeting of States Parties in 2022. The process of destruction must be detailed in a legally-binding, time-bound plan that provides for the verified and irreversible elimination of that state party’s nuclear-weapons programme, including the elimination or irreversible conversion of all nuclear-weapons-related facilities. Such a state must submit a draft of the plan to the other states parties or to the competent international authority within 60 days of becoming a party. The plan must then be negotiated with this authority and submitted to the next meeting of states parties or review conference, whichever comes first, for approval.
- Article VI of the NPT requires that the states parties to the Treaty, including the five nuclear-weapon states parties ‘pursue negotiations in good faith’ on nuclear disarmament. The TPNW is one avenue by which any nuclear-armed state can effectively pursue nuclear disarmament.