Nuclear weapons are receiving renewed attention in the wake of the Israel-Iran conflict. Israel’s air strikes on Iran have led to calls for regional de-escalation and nuclear disarmament. Israel, a nuclear power, struck Iran at a time negotiations about Tehran's nuclear programme was intensified. Iran has long insisted its nuclear programme is for civilian purposes only.

What is nuclear weapon?

The United Nations says nuclear weapons are the most dangerous weapons on earth.

They are extremely powerful explosives whose blast can result in massive destruction and long-term environmental effect.

Nuclear weapons derive power from fission reactions (atomic bombs) or fusion reactions (hydrogen bombs) with their key elements being plutonium-239 and uranium-235, according to experts.

A nuclear explosion releases thermal radiation so intense that almost everything close to where it is detonated is vaporised.

A single nuclear warhead could kill hundreds of thousands of people, according to the Nobel Prize winning anti-nuclear weapons group, the International Campaign to Abolish Nuclear Weapons (ICAN).

‘’Nuclear weapons are the most dangerous weapons on earth.  One can destroy a whole city, potentially killing millions, and jeopardizing the natural environment and lives of future generations through its long-term catastrophic effects.  The dangers from such weapons arise from their very existence,’’ the United Nations Office for Disarmament says. 

How many nuclear weapons are there in the world?

Nuclear bombs have only been used twice in warfare—in the bombings of Japanese cities of Hiroshima and Nagasaki in 1945 by the US.

Modern smaller nuclear bombs have explosive capacities 20 times that of the bomb that destroyed Hiroshima, according to ICAN. That bomb killed about 150,000 people in the immediate months after detonation in the Japanese city.

Nuclear weapons are considered by major powers as the ultimate line of defence. Possessing such weapons is considered a deterrent because of the fear of the destruction that may happen to both the attacker and defender.

The closest the world had ever come to a full-blown nuclear war was in 1961 following a confrontation between the US and the Soviet Union. Since then, countries have generally agreed that the proliferation of nuclear weapons was a problem.

About 12,000 to 13,400 nuclear weapons reportedly remain in the world today and there have been over 2,000 nuclear tests conducted to date, according to the UN Office for Disarmament Affairs. 

Nuclear-weapon countries 

At present there are nine countries in the world that possess nuclear weapons. They are Russia (5,459), US (5,117), China (600), France (290), UK (225), Pakistan (170), India (180), Israel (90) and North Korea (50).

They possessed roughly 12,241 warheads as of the beginning of 2025, according to the Federation of American Scientists (FAS), with the US and Russia possessing approximately 87% of the total inventory of nuclear weapons.

Most nuclear-armed states do not provide information about the size and composition of their nuclear stockpiles.

However, the global inventory of nuclear weapons is declining from a high of 70,000 warheads during the Cold War.

Efforts to eliminate nuclear weapons

The United Nations has sought to eliminate nuclear weapons through a disarmament process, but it has not been successful so far. A number of treaties have since been established with the aim of preventing nuclear proliferation and testing.

These include the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) that is meant to prevent nuclear spread and promote disarmament.

It's considered the cornerstone of global non-proliferation of nuclear weapons with a mechanism of verifying compliance. The International Atomic Energy Agency (IAEA) is responsible for monitoring compliance.

The treaty, which was opened for signature in 1968, entered into force in 1970. So far, 191 states joined treaty, pledging to abide by it.

However, some of the nuclear-armed states have not signed the binding treaty. They are: Israel, India and Pakistan, while North Korea, which had signed, withdrew in 2003.

The nuclear-power countries that have signed the non-proliferation treaty are: The United States, Russia, China, France and the United Kingdom

Nuclear arsenal are costly to develop and maintain. It is estimated that countries that are armed with nuclear weapons spend close to US $225 million a day on nuclear forces, according to ICAN.

Critics have pointed out that the money could be used to uplift people’s quality of life.