80 years after Hiroshima: Nuclear threat still looms over global security

History, with its grim cycles and painful lessons, has every reason to indict humanity. In the week marking the 80th anniversary of the US atomic bombings of Hiroshima and Nagasaki, Russia announced it no longer considers itself bound by the 1987 Intermediate-Range Nuclear Forces Treaty, blaming “the actions of Western countries” for creating a “direct threat” to its security.

Last Friday, US President Donald Trump said he had ordered the deployment of two nuclear submarines “in appropriate regions” following what he described as “highly provocative comments” by former Russian president Dmitry Medvedev.

It is ironic that nuclear weapons still exist, despite the well-known devastation they cause to the planet—and the threat of nuclear sabre-rattling remains as constant as the air we breathe. Aside from white lilies and sombre memorial services for the dead, and sympathy for those emotionally and physically maimed by the two blasts in Hiroshima and Nagasaki, little has moved forward in practical terms.

In the prologue of her book Nuclear War: A Scenario, Annie Jacobsen describes a frightening vision of what the next nuclear bomb explosion might look like. For now, it is only imagination—but reality would unfold within minutes if the bombs were ever detonated, for whatever reason. She writes:

“A 1-megaton thermonuclear weapon detonation begins with a flash of light and heat so tremendous it is impossible for the human mind to comprehend. One hundred and Eighty million degrees Fahrenheit is four or five times hotter than the temperature that occurs at the center of the Earth’s sun. In the first fraction of a second this thermonuclear bomb strikes… there is light…. Soft X-ray light with a very short wavelength. The light superheats the surrounding air to a millions of degrees, creating a massive fireball that expands at millions of miles per hour. Within a few seconds, this fireball increases to a diameter of a little more than a mile (5,700 feet across), its light and heat so intense that concrete surfaces explode, metal objects melt or evaporate, stone shatters, humans instantaneously convert into combusting carbon.”

This, of course, is Jacobsen’s speculative scenario of what might happen if a nuclear bomb were to strike the Pentagon outside Washington. But if such an event were to occur, her imagined horror would become exact, unbearable reality.

In the 653-page book The Effects of Nuclear War, authored along with Philip J Dolan, Samuel Galsstone writes, “There are inherent difficulties in making exact measurements of weapons effects. The results are often dependent upon circumstances, which are difficult, and sometimes impossible, to control even in tests and would certainly be unpredictable in the event of an attack.”

Then, after the immediate destruction there is the curse of a nuclear winter which is inevitable.

A legacy of devastation, a present of peril

Eighty years after the atomic bombings of Hiroshima and Nagasaki, which killed more than 200,000 people and left haunting reminders of nuclear warfare, the world remains on edge. Far from fading into the pages of history, nuclear weapons continue to cast a long, ominous shadow over global peace and security.

While the world has avoided another nuclear strike since 1945, today’s risks may be even more acute driven by geopolitical volatility, advancing technologies and the slow unravelling of disarmament frameworks.

A world still armed to the teeth

As of early 2025, the global stockpile of nuclear warheads stands at approximately 12,241, with the vast majority—over 90 per cent—held by United States and Russia. This massive arsenal is not just a relic of the Cold War but a continually modernised force, featuring increasingly sophisticated delivery systems and warhead designs, Andrew Hammond writes in The Business Times.

While global treaties have aimed to curb proliferation, they have done little to dismantle the core of existing nuclear forces.

Slowing clock of disarmament

The post-Cold War era witnessed a surge of hope for nuclear disarmament. Treaties such as the Strategic Arms Reduction Treaty (Start) and initiatives like the Nuclear Security Summits led to tangible reductions and enhanced controls over nuclear materials. However, this progress has since slowed, if not reversed.

Today, the momentum has shifted towards rearmament. The United States is developing a new generation of nuclear weapons and has indicated an openness to resuming nuclear testing.

Meanwhile, China has more than tripled its arsenal, reaching around 600 warheads. These developments have reignited fears of a new arms race, especially as Russia also pursues advanced systems like hypersonic missiles and underwater nuclear drones. Submarines are indeed deadly platforms for nuclear launches.

Efforts such as the Treaty on the Prohibition of Nuclear Weapons (TPNW), which came into force in 2021, have garnered support from many non-nuclear states. Yet, they have been largely dismissed by nuclear-armed nations. The global appetite for disarmament, once buoyed by the horrors of Hiroshima, is faltering in the face of renewed strategic competition.

Tensions in a fragile world

Geopolitical fault lines are increasingly volatile, exacerbating the risk of nuclear conflict. Recent exchanges between Medvedev and Trump over nuclear threats serve as stark reminders of how easily diplomatic tensions can veer into dangerous territory.

Medvedev’s reference to Russia’s “Dead Hand” nuclear retaliation system and Trump’s counter by repositioning submarines closer to Russia are not just posturing, they reflect the peril of miscalculation in today’s hyper-charged political climate.

Other hotspots, including the enduring India-Pakistan conflict and North Korea’s relentless nuclear testing, add layers of complexity. These regions combine deep-seated historical animosities with nuclear capabilities, making them particularly susceptible to escalation.

Iran, for its part, remains a significant concern. Reeling from attacks on its nuclear facilities, Tehran may further accelerate its nuclear programme, potentially pushing other regional powers like Saudi Arabia and Turkey toward similar ambitions.

Technology: The new wildcard

While nuclear weapons have always embodied existential danger, emerging technologies are making the nuclear scenario even more unpredictable. Artificial intelligence, cyber warfare and advanced missile defence systems are disrupting the traditional logic of nuclear deterrence.

According to Hammond, AI-driven systems, if poorly managed, could make decisions faster than human operators can verify, increasing the likelihood of misjudgements. Meanwhile, cyberattacks on nuclear command and control systems could trigger false alarms or disable safeguards.

The potential for accidental launches or misinterpreted threats has grown significantly in an era of digital warfare and machine decision-making.

During the Cold War and into the 1990s, several false alarms nearly triggered nuclear war due to technical errors and misinterpretations. In the 1950s, a flock of Canadian geese was mistaken for a Soviet bomber attack by radar systems.

The 1960s saw meteor showers and radar reflections from the moon falsely indicating a missile strike, while in 1979, a human error led to a false nuclear alert, causing Norad (North American Aerospace Defense Command) to scramble fighter jets.

A year later, a faulty computer chip triggered a similar scare, prompting the preparation of B-52 bombers and the President’s emergency aircraft. The most serious incident occurred in 1995 when a Norwegian research rocket was misidentified by Russian systems as a US nuclear missile, prompting president Boris Yeltsin to consider a retaliatory strike, an act he ultimately resisted, narrowly avoiding catastrophe.

Terrorism threat

Beyond state actors, the threat of nuclear terrorism has not disappeared. While acquiring a functional nuclear weapon remains a high barrier for non-state groups, the possibility of a radiological dispersal device (dirty bomb) is far more feasible. Such a weapon would use conventional explosives to spread radioactive material, potentially causing mass panic, economic chaos and long-term contamination of urban centres..

Hammond mentions former US defence secretary Robert Gates who once remarked that the thought of a terrorist obtaining a nuclear weapon was what kept him awake at night.

Treaties undermined, norms at risk

International treaties and arms control frameworks that once served as guardrails are now fraying. The Doomsday Clock, maintained by the Bulletin of the Atomic Scientists, was set just one second from midnight earlier this year, the closest it has ever been to global catastrophe.

Eighty years after Hiroshima, the world faces a dual nuclear threat: that of state-led warfare and non-state terrorism. While the horrors of 1945 forged a powerful global aversion to nuclear war, that consensus is under threat. The only way to ensure nuclear weapons are never used again is to eliminate them altogether. Eight decades on, the urgency of that mission has never been clearer.