This century’s worst-case climate scenario is not global warming of 4?C or even 5?C. It is a nuclear winter that would trigger global cooling up to 12?C or 13?C.
That would happen within weeks of the start of a nuclear war, as smoke from burning cities blotted out the sun. The result would be a massive famine, as the ocean’s food chain collapsed and global crops failed.
In most scenarios, hunger would spread around much of the globe and kill hundreds of millions of people, said Alan Robock, a climatologist at Rutgers University and coauthor of two new studies on agriculture collapse and ocean destruction.
How bad it gets depends on the size of the nuclear exchange, but even a “smaller” nuclear war — say, between India and Pakistan — would cause enough global cooling to starve hundreds of millions.
In a war that involved Russia and the US, which have more powerful weapons and larger stockpiles, the death toll would likely exceed half the world’s population.
That means any country willing to launch a first strike is willing to be a mass murderer, Robock said, and anyone willing to launch a retaliatory strike is agreeing to be a suicide bomber.
Robock is among a number of experts who think an aggressive posture in response to Russian President Vladimir Putin’s nuclear threats is not a deterrent, but only puts the world in more danger.
Daniel Ellsberg, the famous whistle-blower who stole hundreds of pages of nuclear secrets, along with the Pentagon Papers, says the same thing in his 2017 book The Doomsday Machine.
The experts I spoke with say the model of deterrence and “mutually assured destruction” is based on an outdated picture, and does not take enough of consideration the risk of a false alarm triggering a first strike, followed by escalation, or the ensuing climate catastrophe that would kill billions. Just as improved climate modeling has sharpened our knowledge of global warming, it has also allowed researchers to better understand the catastrophic costs of nuclear winter.
Talking about annihilation on this scale can make people feel helpless, but it should not. Policy changes could drastically reduce the risk of nuclear apocalypse.
CLIMATE CHANGE
One set of measures should target global warming. That is because climate change caused by emissions could increase the risk of nuclear war by increasing political instability.
“Extreme heat, extensive droughts, terrible disasters and rising seas are creating wave after wave of challenge to societies around the world ... thus affecting the social, economic and political domains of nations — and thereby influencing relations among nations,” wrote Christine Parthemore, head of the Council on Strategic Risks, in a speech for last year’s UN’s climate summit, COP26.
Another set of reforms should make current nuclear policy less threatening. A way to start would be for more countries, including the US, to adopt a “no first use” policy — a pledge never to use nuclear weapons except in retaliation for a nuclear strike.
Last month, the US failed to adopt a such policy in the latest version of the Nuclear Posture Review, a report issued by each new president since the former US president Bill Clinton’s administration. This seems not just dangerous, but immoral. Putin appeared to be threatening first use of nuclear weapons during the Ukraine invasion, a threat the world correctly found monstrous. So why would the US reserve the right to start a nuclear war?
I asked Frank von Hippel of Princeton University’s department of science and global security, and he told me that although US President Joe Biden has expressed a preference for a no-first-use policy, he is getting pushback from the Pentagon and from some of our allies, “who think we shouldn’t take any options off the table.”
The problem is the Pentagon and some of our allied leaders might not be thinking enough about the science of post-nuclear climate change. It is based on well-accepted physics and climate modeling, and still, “the Pentagon has been dismissing this as the hobby horse of a bunch of scientists,” Von Hippel said.
Even in the absence of a no-first-use policy, the US should take its land-based intercontinental ballistic missiles off what is called hair-trigger alert. Right now, if there is a warning of a Russian nuclear attack, the president has about 10 minutes to decide whether to strike back and thereby end the world as we know it, Von Hippel said.
ACCIDENTAL WAR
That leaves the world vulnerable to a so-called accidental nuclear war — an absurd, but totally plausible way to end civilization through a series of misunderstandings. We have come close before, and the risk goes up when international tensions are high.
It is a fallacy to equate an aggressive stance with the willingness to use nuclear weapons, said Pavel Podvig, an independent researcher in Geneva, Switzerland, who was born in Russia and has studied nuclear security issues at the Massachusetts Institute of Technology, Stanford University and Princeton.
The principle of deterrence rests on showing you have the capacity to kill more people than your opponent, he said.
However, if the West tries to deter Russia this way, it needs to demonstrate the consequences of a global calamity would be worse for Russia, and that is not likely to be the case. It goes back to Robock’s comparison to suicide bombing.
“I don’t think there’s any reason to believe that it’s mutually assured destruction that prevents Russia’s using nuclear weapons,” he said. “I believe that it’s the fact that any use would be almost universally considered completely unacceptable.”
He said he does not think Putin would employ so-called tactical weapons in Ukraine, because that notion was conceived to attack large concentrations of troops “and this is not that kind of war.”
However, he worries that even just talking about it is normalizing the use of nuclear weapons.
“The message should be that if you use nuclear weapons, you’re in criminal territory,” he said.
The world should still take an aggressive stance, but in a different way — aggressive in universally condemning the use of nuclear weapons, he said.
Americans are starting to realize how much we should demand climate stability, and decades of activist pressure is finally starting to move the needle on climate change. We should also be demanding a nuclear posture that does everything possible to prevent a nuclear threat to our atmosphere. And we should demand that our lives not be considered collateral damage in a war that cannot be won.
Faye Flam is a Bloomberg Opinion columnist covering science. She is host of the Follow the Science podcast. This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
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