Published in Countercurrents, 6 August 2025
Eighty years have passed since the atomic bombings of Hiroshima and Nagasaki seared the world’s conscience and introduced an age where the survival of nations could be decided in minutes. The post war decades saw a dangerous nuclear arms race, but also the gradual building of arms control agreements to slow that race and reduce stockpiles. In the first years after the Cold War, there was cautious optimism as US and Russian arsenals shrank from their peak of around 70,300 warheads in 1986 to far lower levels. But that optimism has faded. In 2025, the world stands at the threshold of what many experts warn is a new and even more unpredictable nuclear age.
The latest SIPRI Yearbook paints a stark picture. Nine countries—the United States, Russia, the United Kingdom, France, China, India, Pakistan, North Korea, and Israel—together hold an estimated 12,241 nuclear warheads. Of these, about 9,614 are in military stockpiles ready for potential use, 3,912 are deployed on missiles and aircraft, and around 2,100 are kept on high alert. Russia and the United States account for about 90 percent of all nuclear weapons and 83 percent of those in active service. For decades after the Cold War, dismantling retired warheads—mainly by Washington and Moscow—outpaced the production of new ones. That trend has now reversed. The pace of dismantlement has slowed, new deployments are accelerating, and nearly all nuclear-armed states are engaged in intensive modernisation.
In the United States and Russia, the size of active stockpiles has been relatively stable in recent years, but both countries are upgrading their nuclear triads and adding new systems that could expand their arsenals. Without a successor to the 2010 New START treaty, which limits deployed warheads and expires in February 2026, both sides are likely to increase the number of warheads on strategic missiles. US modernisation faces planning delays and cost overruns, while Russia’s programme has seen technical setbacks such as the failure of its Sarmat intercontinental ballistic missile test. Still, each is expected to expand deployments in the coming years—Russia by loading more warheads on each missile and reactivating silos, and the US by increasing warheads on existing launchers and introducing new non strategic weapons, partly in response to China’s nuclear build up.
The political climate surrounding nuclear policy has become more volatile. In July, President Trump announced that two “nuclear” submarines had moved closer to Russia in response to provocative statements from a senior Kremlin official. It was unclear whether he meant nuclear armed or nuclear powered submarines, but the ambiguity amplified the perceived threat. Former congressman John Tierney, now with the Center for Arms Control and Non Proliferation, warned that such public threats carry more risk than reward, creating opportunities for miscalculation. Erin Dumbacher of the Council on Foreign Relations also stressed that all nuclear states should adopt formal commitments to keep launch decisions in human hands, not artificial intelligence.
The episode occurred against a backdrop of hardening Russian positions. Moscow recently declared it would no longer honour its unilateral moratorium on deploying intermediate and shorter range missiles, a class of weapons banned under the 1987 INF Treaty until the US withdrawal in 2019. Russia argues that NATO has ignored its restraint and is moving US missile systems into Europe and the Asia Pacific for exercises aimed at Russia. The Foreign Ministry says these actions create destabilising missile forces near its borders and justify countermeasures. Kremlin spokesman Dmitry Peskov has stated Russia reserves the right to deploy these missiles if NATO “provokes” close to Russian territory.
Amid this escalation, there are still calls for structured dialogue. Rose Gottemoeller, former NATO deputy secretary general, has argued in the Bulletin of the Atomic Scientists that simply extending New START would not be enough. She proposes a new agreement—politically owned and championed by Trump if he is in office—that preserves verification measures such as inspections and data exchanges, maintains current warhead and launcher limits, and develops parallel negotiations with China. Her plan includes a freeze on all nuclear warheads, not just those deployed, reviving a step Trump and Putin agreed to in 2019. This could open the door to direct warhead monitoring, something past treaties have avoided by limiting only delivery systems. Gottemoeller also points to the need for bans on deploying nuclear weapons in orbit and for discussions on missile defence—particularly Trump’s proposed “Golden Dome” system—and its implications for deterrence stability.
While US Russia rivalry dominates global nuclear politics, the broader picture is shifting toward a multipolar nuclear world. China’s arsenal, now around 600 warheads, is projected by the US Defence Department to reach 1,500 by 2035, raising questions about its “no first use” pledge. The United Kingdom has reversed previous reductions and plans to increase its ceiling from 180 to 260 warheads. In the Global South, proliferation remains a quiet but serious concern. Israel maintains an undeclared stockpile of roughly 90 warheads. India and Pakistan are both producing more, though most remain in central storage rather than deployed. North Korea is thought to have material for up to 90 warheads, with about 50 assembled. Iran’s nuclear ambitions continue to fuel regional tension, especially given the erosion of the 2015 nuclear deal.
The nuclear challenge is no longer defined solely by weapons counts or missile deployments. As Cindy Vestergaard warns, advanced technologies are reshaping how nuclear weapons can be developed, concealed, detected, and controlled. Artificial intelligence offers powerful tools for data analysis and anomaly detection but also enables deepfakes, disinformation, and cyberattacks. Additive manufacturing (3D printing) can produce rare components cheaply but risks bypassing export controls and introducing counterfeit parts into supply chains. AI powered drones can conduct surveillance or even potentially deliver nuclear payloads, while quantum computing threatens to break existing encryption, undermining the security of nuclear command and control systems. Quantum sensors could, in time, expose hidden missile launchers or submarines, eroding traditional deterrence assumptions.
These disruptive technologies are “dual use”—capable of improving verification systems but also enabling new forms of evasion. Agencies such as the International Atomic Energy Agency and the Comprehensive Nuclear Test Ban Treaty Organization could benefit from AI driven analytics, secured additive manufacturing for tracking nuclear parts, and quantum sensors for non intrusive inspections. Yet the same innovations could make nuclear proliferation harder to detect and control, especially in a world where secrecy around arsenals is increasing. The principle of “trust but verify” must evolve into “verify, verify, verify” to address these new risks.
Addressing this complex setting will require a blend of old and new approaches. First, existing verification and transparency mechanisms must be reinforced and adapted to cover emerging technologies. Second, new arms control frameworks should run in parallel—one track for maintaining strategic parity with Russia, another for building predictability with China. Third, confidence building measures such as pledges against AI controlled launch decisions should be expanded to all nuclear armed states. Fourth, missile proliferation must be addressed through combined efforts on integrated defences and discussions on how such systems affect strategic stability. And finally, the nuclear powers must engage the Global South, both to discourage further proliferation and to include them in shaping norms for the new technological era.
The lesson of Hiroshima is not only that nuclear war is catastrophic, but that it is irreversible once begun. The nuclear world of 2025 is more complicated than during the Cold War, with more actors, more types of weapons, and more technologies that can destabilise deterrence. Without urgent and sustained diplomacy, the world risks sliding into an unconstrained nuclear competition—one in which accidents, misjudgements, or technological surprises could trigger disaster. The choice facing leaders today is whether to let this second nuclear age unfold unchecked or to summon the political will to contain it. The stakes, as they were eight decades ago, are nothing less than the future of global security.
