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Probability of Nuclear War

Most people go about their lives giving minimal thought to the consequences or probability of nuclear war.  The consequences are generally understood to be catastrophic and, as a result, the probability of nuclear war is thought to be extremely low.  But is this actually the case?  Should people feel safe from nuclear war on the basis of a perceived low probability of occurrence?

Since the consequences of nuclear war could be as high as human extinction, the probability of such an outcome would preferably be zero, but this is clearly not the case.  Nuclear weapons have been used twice in the past 72 years, at a time when only one country possessed these weapons.  Today, nine countries possess nuclear weapons, and there are nearly 15,000 of them in the world.

Nuclear deterrence, based upon the threat of nuclear retaliation, is the justification for possession of these weapons. It is, however, a poor justification, being unethical, illegal, and subject to catastrophic failure.  Over the 72 years of the nuclear era, nuclear deterrence has come close to failing on many occasions, demonstrating weaknesses in the hypothesis that threat of retaliation will protect indefinitely against nuclear war.

I asked several individuals working for nuclear disarmament, all Associates of the Nuclear Age Peace Foundation, about their views on the probability of nuclear war.

Martin Hellman, a professor emeritus of electrical engineering at Stanford, had this to say: “Even if nuclear deterrence could be expected to work for 500 years before it failed and destroyed civilization – a time period that sounds highly optimistic to most people – that would be like playing Russian roulette with the life of a child born today. That’s because that child’s expected lifetime is roughly one-sixth of 500 years. And, if that ‘nuclear time horizon’ is more like 100 years, that child would have worse than even odds of living out his or her natural life. Not knowing the level of risk is a gaping hole in our national security strategy. So why does society behave as if nuclear deterrence were essentially risk free?”

I next asked John Avery, an associate professor of quantum chemistry at the University of Copenhagen, for his view of the probability of nuclear war by end of the 21st century.  He responded:

“There are 83 remaining years in this century. One can calculate the probability that we will reach the end of the century without a nuclear war under various assumptions of yearly risk. Here is a table:

Yearly risk           Chance of survival
1%                             43.4%
2%                             18.7%
3%                              7.9%
4%                              3.4%
5%                              1.4%

“One has to conclude that in the long run, the survival of human civilization and much of the biosphere requires the complete elimination of nuclear weapons.”

Finally, I asked Steven Starr, a scientist at the University of Missouri, who responded in this way:

“I’m not sure if I can provide any sort of numerical value or calculation to estimate the risk of nuclear war in a given time period. However, I certainly would say that unless humans manage to eliminate nuclear arsenals, and probably the institution of war itself, then I think it is very likely that nuclear weapons will be used well before the end of the century.

“But I certainly would say that unless humans manage to eliminate nuclear arsenals, and probably the institution of war itself, then I think it is inevitable that nuclear weapons will be used well before the end of the century.  There are just too many weapons in too many places/countries . . . something close to 15,000 nuclear weapons, right? . . .  and there are too many conflicts and injustices and power-hungry people who have access to and control over these weapons. There are just too many possibilities for miscalculation, failures of technology, and simply irrational behavior, to imagine that we can continue to indefinitely avoid the use of nuclear weapons in conflict.

“Thus I am very happy to see that a treaty to ban nuclear weapons is now being negotiated at the UN. This proves to me that there are a great many people and nations that are fully aware of the nuclear danger and are taking action to stop it.”


The odds of averting a nuclear catastrophe are not comforting.

We are playing Nuclear Roulette with the futures of our children and grandchildren.

The only way to assure that the probability of nuclear war goes to zero is to eliminate all nuclear weapons.

One way to support the goal of nuclear zero is to support the Nuclear Ban Treaty currently being negotiated at the United Nations.

Vaya aquí para la versión española.

David Krieger
David Krieger
David Krieger is President of the Nuclear Age Peace Foundation (www.wagingpeace.org). He is the author and editor of many books on peace and nuclear weapons abolition, including "Speaking of Peace: Quotations to Inspire Action."