Nuclear warNuclear War Could Be Devastating for the U.S., Even If No One Shoots Back

By Joshua M. Pearce

Published 26 February 2020

The White House’s 2021 budget calls for $28.9 billion for the Pentagon for nuclear weapons and a 20 percent increase to $19.8 billion for the National Nuclear Security Administration. Yet the U.S. already has over 3,000 nuclear weapons. The U.S. could only safely use a fraction of them without killing Americans with an unintended adverse series of cascading environmental effects: Soot from the burning of cities following numerous nuclear blasts would cause a significant drop in global temperature, blocking the sunlight from reaching the Earth’s surface. This would cause a drop in precipitation, increased ultraviolet radiation resulting from a badly damaged atmosphere, and a breakdown in supply chains and food production. In short, a nuclear attack using only a few nuclear weapons would be exceedingly damaging for the aggressor nation.

The White House’s 2021 budget calls for $28.9 billion for the Pentagon for nuclear weapons and a 20 percent increase to $19.8 billion for the National Nuclear Security Administration.

Yet the U.S. already has over 3,000 nuclear weaponsAnd my research shows that the U.S. could only safely use a fraction of them without killing Americans with an unintended adverse series of cascading environmental effects.

My models and those of others show that soot from the burning of cities following numerous nuclear blasts would cause a significant drop in global temperature, blocking the sunlight from reaching the Earth’s surface. This would cause a drop in precipitation, increased ultraviolet radiation resulting from a badly damaged atmosphere, and a breakdown in supply chains and food production.

The study my colleague, David Denkenberger, and I did shows how damaging a nuclear attack using several nuclear weapons would be for the aggressor nation.

Nuclear Winter versus Nuclear Autumn
You have probably heard of “nuclear winter.” That’s when multiple nuclear weapon strikes cause cities to burn, putting massive amounts of smoke into the upper atmosphere and blocking sunlight for years. The resultant agricultural loss would cause massive global starvation.

The science behind nuclear winter influenced Russian president Mikhail Gorbachev and U.S. president Ronald Reagan to end the Cold War and begin nuclear disarmament.

The agricultural loss from the less-known “nuclear autumn” – meaning a smaller amount of smoke – would range from a 10 percent to 20 percent drop in global agriculture. That’s enough to cause widespread food shortages, still causing many millions of people to starve.

Every nation willing to use its nuclear weaponry must determine whether it has the ability to survive the problems of its own making. Nations with nuclear weapons all ascribe to the concept of nuclear deterrence – the idea that more nuclear firepower is intimidating and makes other countries think twice before picking a fight.

My colleague and I wanted to know: How many nuclear weapons could a country use against an enemy without causing a nuclear autumn and killing their own people?

Simulating Nuclear War
First, we determined how many nuclear weapons would be enough to provide substantial deterrence for a “worst case” enemy – the most populous target nation. We looked at the threat posed by a number of different countries, from those with around 100 weapons, like India or Pakistan, to Russia, which has about 7,000.