China is fuelling fears of a 'more dangerous' Cold War. Here's how it could unfold

 Shortly before lunchtime on Oct 30 1961, a Soviet plane flying above the Arctic archipelago of Novaya Zemlya dropped the most powerful nuclear bomb ever created.

The USSR’s “emperor bomb” was 3,000 times more powerful than the US atomic attack that killed 140,000 people in Hiroshima two decades earlier.

When it exploded, it unleashed a six-mile-wide fireball and a mushroom cloud that loomed more than 40 miles into the sky. And the Soviets were testing it at only half of its designed capacity.

Since then, decades of negotiations and arms-control treaties have massively reduced American and Russian warhead arsenals, with neither side testing a nuclear bomb in more than three decades.

But the last of these bilateral agreements has expired – and with it, hopes that the nuclear arms race had been consigned to the history books.

On Feb 5, the New Strategic Arms Reduction Treaty (Start), which capped the number of deployed nuclear warheads held by the US and Russia, came to an end.

It is the first time since the 1970s that the two powers have had no agreement in place without at least negotiations for a new treaty under way.

At a time of huge geopolitical upheaval, analysts and diplomats are concerned that the stage is set for a new nuclear arms race – one that could prove even more dangerous than the world has seen before.

This is because for the first time in the history, the competition will not just be confined to Russia and the US.

China has also been developing nukes at a startling trajectory, more than doubling its stockpile of warheads over the last six years.

And it is China’s rise that will be Donald Trump’s biggest concern.

A three-way race will be hugely destabilising for the world order. If America tries to build an arsenal large enough to deter its twin foes at once, it will spur an even more dramatic increase in their respective stockpiles.

“This is the end of an era. It is not the end of arms control but it is definitely the end of arms control as we know it,” says Heather Williams, director of the Project on Nuclear Issues at the Centre for Strategic and International Studies (CSIS).

Smaller nuclear powers such as Britain and France will also face pressure to bulk up, particularly at a time when US security guarantees feel less reliable. And there will likely be a proliferation of new nuclear states.

Trump has insisted for decades that he wants denuclearisation. But he seems to have no strategy to get there. His plans to build a new missile defence system – which he refers to as the “Golden Dome” – are only fanning the flames.

‘Complete collapse of everything I worked on for 45 years’

Nikolai Sokov, who worked on Cold War nuclear arms treaties from the Russian side, says: “I was always quite proud of what I did. I negotiated agreements that resulted in about an 80pc reduction of nuclear weapons.

“Now I see a complete collapse of everything that I worked on for 45 years.”

Cold War nuclear arms negotiations between the Soviet Union and the United States were intense and confrontational.

“They would say, ‘No, your proposal is completely unacceptable, it’s bull----’,” says Sokov, who was working for the USSR’s foreign ministry in the late 1980s, travelling between meetings at the US and Soviet missions in Vienna several times per day.

Once, he and his US counterparts spent 18 hours in non-stop negotiations over a draft text, haggling over the meaning of five individual words in the document.

“Food was brought to us at our table. He suffered because I smoke. Eventually we agreed on three words, and we had a reasonably good idea on how to finalise the remaining two,” says Sokov.

“Words mean something. They’re where heavy bombers are located, or how you look at warheads during inspections. It’s never a word, it’s actual weapons.”

But these lines of communication and debate have now disappeared completely.

The New Start agreement, signed by the then US president Barack Obama and Russian president Dmitry Medvedev (Vladimir Putin was then prime minister) in 2010, was the last in the line of successive treaties that has reduced each power’s respective hoard of deployed warheads from 12,000 in the early 1990s to 1,550.

The deal monitors all three nuclear weapon delivery systems: intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs) and bombers.

It also agreed rules around transparency, including the provision that each country would hold 18 on-site inspections of its nuclear weapons per year.

In 2023, Putin suspended Russia’s participation in the treaty, halting inspections and data exchanges. However, both sides have signalled they have kept within the numerical limits on the treaty. Currently, the US has 1,419 deployed strategic warheads while Russia has 1,549.

In September, Putin said Russia was prepared to maintain the numerical limits of the treaty for one more year if the US “acts in a similar spirit”. But in January, the Kremlin said it had still not received a response from Trump.

“If it expires, it expires. We’ll do a better agreement,” the US president told The New York Times last month. But there are no talks in the works.

“No one is even talking about negotiations, except for very general statements,” says Sokov, who is now a senior fellow at the Vienna Center for Disarmament and Non-Proliferation.

“The problem is we’re losing all kinds of predictability that we used to have.”

The treaty expires at a time when Putin has already been using nuclear threats to pressurise the West over its support for Ukraine.

The Russian leader has placed nuclear weapons on heightened alert and announced that Russian nuclear weapons will be deployed in Belarus. He has also been investing heavily in new delivery systems, such as Russia’s Oreshnik intermediate-range ballistic missiles that can travel at 2.1 miles per second.

Without a nuclear disarmament treaty in place, the first thing that the US and Russia are likely to do is rapidly increase the number of warheads.

Both countries have much larger stockpiles beyond what they have loaded onto missiles.

Including “non-deployed and retired warheads” – those which cannot be launched at the touch of a button – the US has 5,225 while Russia has 5,580. Combined, they hold 87pc of the world’s nuclear weapons.

In the short term, simply by uploading more of its existing warheads onto its ICBMs, SLBMs and bombers, each side could double its strategically deployed warheads to somewhere around 3,000 each within a year or two, says Daryl Kimball, the executive director of the Arms Control Association.

So the big question is to what extent each country ramps up its overall holdings and develops new weapons at a time when relations are frayed.

‘A new, unconstrained nuclear arms race’

Georgia Cole, of Chatham House’s international security programme, says: “Definitely the direction that we’re headed in is a new, unconstrained nuclear arms race.

“Not only does that mean that we could be looking at a world with a lot more nuclear weapons like we had in the Cold War, but also this will be without the verification and transparency measures and without dialogue. That also increases the risk of miscalculations and escaations.”

Nuclear arms experts are unanimous in their warnings about a fresh 21st-century weapons race, which would put the Cold War in the shade.

Rose Gottemoeller, a former deputy secretary general of Nato, says: “Even in the height of the Cold War, we kept up our nuclear arms control cooperation.

“If there are absolutely no negotiated restraints on the nuclear capitals, one has to be afraid that we could be on the cusp of a nuclear arms race.”