What the Volcano Can Teach Us About Nuclear War

Think the ash cloud was bad? That's nothing compared to what would happen if India and Pakistan exchange just a few nukes.

Thousands of people were stranded across the globe. Perishable foods unable to be transported to Europe were spoiling in Kenyan warehouses. Altruistic Britons organized a flotilla of boats to ferry their stranded compatriots from Calais across the English Chanel to Dover—à la Dunkirk. Sounds like the end of the world, but all the drama and chaos was actually caused by an ash-spewing volcano.

The Icelandic menace whose name we cannot pronounce shut down air travel in Europe, with global consequences. Eyjafjallajökull, for all its volcanic fuming, can hardly even compare to a major disaster. Tsunamis, earthquakes and droughts have all done far worse—and so can we.

Even though “duck and cover” drills have gone the way of the dodo and VHS, people still understand that a nuclear explosion would cause unfathomable death and destruction. What they probably do not realize is that if a nuclear war broke out anywhere, the fallout would have global consequences that would kill millions of people, disrupt climate patterns, and threaten global agricultural collapse. How do we know that would happen? Volcanoes.

The 1815 explosion of Mt. Tambora in Indonesia was the biggest volcanic eruption in the past 500 years. The ash and dust it kicked up spread around the world, blotted out the sun, and cooled global temperatures by five degrees Fahrenheit for a year. The next year, 1816, became known as “The year without a summer” and New England saw crop-killing frosts every month. With crops failing, grain supplies dropped, food prices skyrocketed, and farmers sold animals they could not feed. Widespread famines began setting in.

Climate scientists have applied lessons from volcanic eruptions like Tambora to estimate how nuclear fallout would affect the global climate. The projections aren’t good.

Put aside Cold War ideas of a U.S.-Russian nuclear exchange, India and Pakistan are the world's tensest nuclear rivals. Both nations possess more than 100 nuclear weapons and they have mobilized for nuclear war with each other—twice. The scientists Alan Robock and Owen Brian Toon estimate (pdf) that in even a limited exchange—perhaps 50 nuclear explosions on each side—20 million Indians and Pakistanis would die from the nuclear blasts, fires, and radioactive fallout. But that's just the beginning. The firestorm ignited by the bombs would spread heavy smoke across South Asia and send 5 million tons of particles into the atmosphere. Within 49 days, the particles would “blanket the earth, blocking enough sunlight that skies would look overcast perpetually, everywhere.” With less sun, the global average surface-air temperature would drop by 2.7 degrees Fahrenheit. Precipitation averages would fall and climate patterns would change dramatically.

With shortened and disrupted growing seasons, global agricultural production would be pushed to collapse. These declines in agricultural output would be felt everywhere simultaneously, grinding international markets to a halt. Since most cities or countries only keep enough food on hand for a very short period, hunger would start in a grocery store near you. Scientists estimate that the total grain stored on the planet today would only feed the earth’s population for about two months. After that, the world could start looking like The Road.

The ash cloud from Eyjafjallajökull provided a dramatic example of how fragile our interconnected economy can be. We should remember that when we consider the importance of eliminating nuclear weapons.

Global nuclear stockpiles dropped from a Cold War high of over 70,000 nuclear weapons in 1986 to about 23,000 weapons today—with 96 percent in the United States and Russia alone. But less than half a percent of the existing global stockpile could devastate the globe. Right now nuclear weapons are being sought by terrorists; held by tense military rivals, poised on alert to launch on a moment’s notice; and occasionally lost by the most powerful country in the world. Our only hope for real security is to keep working towards a world without nucear weapons.

Alexandra Bell is the Project Manager at the Ploughshares Fund and a Truman National Security Fellow. Ben Loehrke is a Research Assistant at the Ploughshares Fund and a graduate student at the University of Maryland School of Public Policy.

Illustration by Johana Tran.