Launching more than 100 nuclear warheads at a foe would catastrophically backfire on any nation deploying them, a study has shown.
Scientists found that the “environmental blowback” of such an attack would lead to unacceptable losses – even if the enemy failed to retaliate.
A major clash involving the use of 1,000 nuclear warheads by the US would result in 50 times more deaths of Americans than occurred in the 9/11 terrorist attacks, said the researchers.
And this was without a single nuclear strike on the US.
The study found that a nuclear arsenal of no more than 100 weapons provided a “safe” level of deterrence.
Nine nations, the US, Russia, the UK, France, China, India, Pakistan, Israel and North Korea, collectively hold an estimated 15,000 nuclear warheads.
The US alone has 6,800 nuclear warheads, of which 1,800 are in active service and deployed.
Russia has 7,000 warheads and the UK 215, according to a report published last year by the US Defence Intelligence Agency.
The effects of “environmental blowback” include lowered temperatures due to dust from burning cities blocking out sunlight, reduced rainfall, falling food production, the breakdown of supply chains, and increased levels of ultra-violet radiation, said the scientists in the journal Safety.
A “nuclear autumn” triggered by lack of sun – less severe than a “nuclear winter” – would still result in agricultural losses ranging between 10% and 20%, according to the study.
The scientists predicted that food shortages would lead to severe rationing, starvation and numerous deaths due to civil disturbance.
Lead author Professor Joshua Pearce, from Michigan Technological University, said: “With 100 nuclear weapons you still get nuclear deterrence, but avoid the probable blowback from nuclear autumn that kills your own people.
“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.”
The September 11 2001, attack on New York by the al Qaida terror group using passenger jets flown into the twin towers of the World Trade Centre cost 2,977 innocent lives.
The scientists calculated the grim consequences of launching just 100 nuclear warheads at China’s most populated cities.
More than 30 million people were likely to die just in the initial blast, exceeding the death toll of even a severe pandemic.
Fear of such a terrible scenario would provide “plenty of deterrence”, the researchers claimed.
Other countries besides the US were at even greater risk from nuclear blowback, they claimed.
Prof Pearce said: “It is not rational to spend billions of dollars maintaining a nuclear arsenal that would destabilise your country if they were ever used.
“Other countries are far worse off. Even if they fired off relatively few nuclear weapons and were not hit by any of them and did not suffer retaliation, North Korea or Israel would be committing national suicide.”