Why It's Impossible To Win a Nuclear War

Nuclear war would be catastrophic – but  maybe not just for the reasons you think. Hi, I'm Cameron, and this is MinuteEarth. Yes, it’s true that immediately following  the detonation of a nuclear weapon, everything – and everyone – inside the blast zone  is incinerated.

And yes, over the following days, weeks, and years, radiation poisoning causes death  and debilitating disease in those just a little farther afield. But that’s just the first domino  of devastation: radioactive fallout, refugees, looting, and large-scale damage to infrastructure  will all be bad, but the smoke is what has the farthest-reaching – and deadliest – effects. When lots of smoke goes into the atmosphere at one time, it absorbs sunlight, which means it  can affect the climate.

After Mount Pinatubo erupted in 1991, the resulting ash cloud  temporarily dropped global temperatures by an average of a degree Celcius. Smoke from  mega-wildfires can have similar local effects. The smoke from a burning city is even  more of a problem, though.

As cities, with all of their buildings, plastics, asphalt,  etc – as all of this stuff burns. . .

It creates smoke with tons of free-floating groups of  carbon atoms known as “black carbon,” which is the special sauce of our nuclear doom.  These dark particles soak up sunlight and warm the surrounding air, making it buoyant  and lofting the smoke into the stratosphere. Smoke from wildfires and volcanoes also make  it high in the air, but these sources don’t produce much black carbon.

As a result, their  lighter-colored smoke doesn’t absorb as much sunlight, and therefore won’t float very long. But  smoke made mostly of black carbon can stay aloft for as long as a decade, riding air currents,  and cooling the planet by absorbing the sun's rays in the upper atmosphere so that they (and  their heat) never make it to the surface below. Scientists have recently calculated that just 15  nuclear bombs could create as much as five million tons of black carbon – that’s enough to cool  the planet by an average of 2 degrees Celsius.

But wait a minute – we have detonated more than  2,000 nuclear bombs – why haven’t we experienced this cooling already? Well, the vast majority  of nuclear detonations have happened either high in the atmosphere, in remote places, or deep  underground. That’s all in order to minimize the potential for damage – including the damage that  would be caused by megatons of black carbon soot.

Two nuclear bombs have been used to their  full – and devastating – potential. But, somewhat frighteningly, those were small  bombs compared to what we have now. Today, not only are nuclear weapons way bigger, we  also have way more of them than we did then, albeit not nearly as much as existed during the  Cold War.

Still, a war between nuclear powerhouses could create as much as 150 million tons of black  carbon, enough to drop global temperatures by an average of 16 degrees. For reference, during the  most recent ice age – you know, when glaciers covered half the earth – global temperatures  were just 7 degrees colder than they are now. And if a nuclear-triggered mini ice age were to  occur, it would freeze food production in most of the world, many of those who manage to survive the  bombs and radiation and freezing conditions would suffer from inevitable global food shortages; as  many as 5 billion people worldwide might starve in the first year – that’s nearly two-thirds of  the global population.

At northern latitudes, it gets even worse – up to 99% of  people there may starve to death. A war that heats up to the point of going  nuclear could leave everyone in the cold. This video was brought to you by the Future  of Life Institute to celebrate recipients of the Future of Life Award.

This award is  given annually to individuals who have steered the course of history away from  disaster without having received much public recognition at the time. The 2022  Award went to John Birks, Paul Crutzen, Jeannie Peterson, Alan Robock, Carl Sagan,  Georgiy Stenchikov, Brian Toon and Richard Turco for their roles in discovering and  popularizing the science of nuclear winter.