The size of the world’s nuclear arsenal has quietly increased in several countries amid fears of World War III.

Officially, five countries – China, Pakistan, India, Israel, and North Korea – have increased their nuclear stockpiles by over 700 warheads over the past 40 years.

But according to a 2024 report by the Federation of American Scientists (FAS), a nonprofit global policy think tank, there are concerns that three other nations with nuclear weapons may be quietly amassing even more arms in preparation for a potential nuclear conflict.

These worries arise at a time when organizations like the US National Nuclear Security Administration (NNSA) have highlighted that a treaty aiming to permanently prohibit nuclear testing has hit an impasse, while countries such as Russia and China have been observed constructing new facilities at their nuclear weapons facilities.

However, the US government announced last month that it will also restart its nuclear testing programs in secret underground facilities.

FAS released the estimated global nuclear warhead inventories for 2024, showing there are 12,121 nuclear warheads scattered across nine nations. 

Russia outnumbers the US by several hundred warheads.

The two nations control roughly 88 percent of this stockpile, with Russia reportedly holding 5,580 bombs and the US possessing 5,044.

China, France, India, Israel, North Korea, Pakistan, and the UK control the rest of world’s remaining 1,500 nuclear bombs.

Global tensions appear to be boiling over, with President Donald Trump warning Ukrainian president Volodymyr Zelensky that he is ‘gambling with World War III’ by not agreeing to America’s peace terms. 

A new report estimates that there are still over 12,000 nuclear warheads in the world, controlled by 9 different countries

The threat of a global war involving nuclear weapons continues to remain high due to ongoing conflicts in the Middle East and Ukraine

China also hit back at Trump’s vow to impose further tariffs with a stark warning that Beijing is ready for a tariff war or ‘any other type of war.’

Meanwhile, European leaders are publicly declaring their ability to defeat Russia in a major conflict.

‘Europe as a whole is truly capable of winning any military, financial, economic confrontation with Russia – we are simply stronger,’ Poland’s Prime Minister Donald Tusk told Ukrainian leader Volodymyr Zelensky ahead of an EU summit. 

‘We just had to start believing in it. And today it seems to be happening.’

According to the data from the Federation of American Scientists, there is clear evidence that five nations have seen their nuclear stockpiles grow since 1986 – China (224 to 500), Pakistan (0 to 170), India (0 to 172), Israel (44 to 90), and North Korea (0 to 50).

The experts found that 2,100 American, Russian, British, and French ‘warheads are on high alert, ready for use on short notice.’

 Since no country on Earth openly reveals exactly how many nuclear weapons they have in their arsenal, the team made an educated guess, which they note has become even harder to do in recent years.

To do this, FAS used publicly available information, historical records, and leaked data from government officials to compile their 2024 numbers. 

The US and Russia have about 2,500 nuclear warheads that are classified retired and still waiting to be dismantled, more than the combined nuclear stockpiles of every other nation with these weapons

However, scientists said governments are once again becoming tight-lipped about their nuclear secrets.

The first Trump Administration ended the total disclosure policy of America’s nuclear stockpile in 2019. It was a policy that had been in place since the Obama presidency in 2010.

Although the Biden Administration said they would restore the nation’s policy on nuclear transparency in 2021, researchers noted that the Biden White House immediately failed to declassify any US stockpile data for three straight years.

As of 2024, both the US and Russia are no longer exchanging data on their strategic warheads and launchers deployed around the world – even though this is mandated by the New START Treaty.

The agreement sought to increase US safety by placing limits on Russia’s deployed intercontinental nuclear weapons.

Overall, the think tank said that the US was still the most transparent nation when it comes to the size of their nuclear arsenal, noting that the country’s allies in Israel were the most secretive.

Another of America’s allies, the UK, has also stopped providing updates on their military’s nuclear stockpile – which researchers said sits at 225 warheads.

According to the Federation of American Scientists, 2,100 nuclear weapons worldwide ‘are on high alert, ready for use on short notice’

The new report noted that not every nuclear warhead is capable of being launched in a war right now.

Of the 12,121 warheads believed to be in existence as of 2024, about 9,585 are officially part of the world’s military stockpiles – meaning these countries can launch them as missiles from ships, submarines, or planes.

The rest are nuclear warheads which have been retired and are still waiting to be dismantled. This includes over 1,300 in the US and another 1,200 in Russia.

The research team added that just over 3,900 nuclear bombs are currently attached to missiles or sitting on active bomber bases.

However, even those figures would be ‘overkill’ in any nuclear war, according to at least one study.

In 1986, experts estimated that the world’s nuclear stockpile grew to 70,300 bombs, but that number has dropped since the end of the Cold War

Researchers believe several countries with access to nuclear weapons are currently increasing their stockpiles amid fears of a world war breaking out soon

In 2018, a team from Michigan Tech argued that the detonations of just 100 nuclear missiles would be enough to effectively destroy society.

They added any country using more than 100 nuclear weapons, even if no one retaliated, would cause so much environmental damage that the attack would end up killing that nation’s own people.

Professor Joshua Pearce said: ‘If we use 1,000 nuclear warheads against an enemy and no one retaliates, we will see about 50 times more Americans die than did on 9/11 due to the after-effects of our own weapons.’

Less than 40 years ago, researchers noted that there were approximately 70,300 nuclear warheads worldwide. 

During the 1990s, however, those numbers plummeted after the end of the Cold War between the US and Russia and the signings of several arms control treaties.