Over the years, we’ve heard hundreds of time about how we have enough nuclear weapons to destroy the world. But is that actually true? Could we actually destroy all life on this planet? We crunch the numbers and see exactly how bad it would be if every nuclear weapon in the world went off at once. And learn a little something about Robert Oppenheimer along the way.


Christopher Nolan’s Oppenheimer exploded into theaters last week, telling the story of J. Robert Oppenheimer, a nuclear physicist who led the Manhattan project that created the first nuclear bomb. And all the moral conflicts that come with that.

He would later say that seeing the first bomb go off reminded of a line from the Bhagavad Gita, “I am become death, the destroyer of worlds.”

He’s kind-of become associated with that line, but according to his brother, who was there with him when the bomb went off, that’s not what he actually said.

What he actually said, apparently was, “I guessed it worked.”

Not quite as profound, but I’m sure he was thinking the other thing.

Either way, I imagine as the years passed afterward, seeing the world stockpile these weapons thousands of times over was… a heavy burden. He may have truly brought about the thing that could destroy the world.

But could it?

Like when I was growing up, I always heard that there were enough nuclear weapons to end all life on the planet. Which, I thought was insane. Why would you need that many?

Like maybe just annihilate one country? Does it have to be all of them?

Or maybe… it sounds crazy because it’s not actually true.

The world’s a big place, it’s survived a lot of things…

So what if every nuclear weapon on Earth went off at once?

To answer this question, we first have to define some things. Things like what is a nuclear weapon.

A nuclear weapon is defined as a device that releases explosive energy from nuclear fission, fusion, or a combination of the two.

Atomic bombs are commonly fission weapons. Thermonuclear bombs, or hydrogen bombs, are fusion weapons.

Their blast energy is often referred to in terms of kilotons (1,000 tons) and megatons (1 million tons) in equivalent weights of conventional TNT explosives.

According to the Federation of American Scientists, nine countries possess around 12,500 nuclear warheads as of early this year.

These nations are:

  • Russia
  • United States
  • China
  • France
  • United Kingdom
  • Pakistan
  • India
  • Israel
  • North Korea

There are also six nations hosting nuclear weapons:

  • Italy
  • Turkey
  • Belgium
  • Germany
  • Netherlands
  • Belarus

Including those last few countries, that means there are approximately 12,700 warheads around the world.

So in total, yeah 12,500 weaons, that’s bad, sure, but not nearly as bad as during the cold war. At one point there were an estimated 60,000 to 70,000 weapons worldwide.

According to the International Campaign to Abolish Nuclear Weapons, Russia holds the most confirmed nuclear weapons at 5,997.

The U.S. is next with 5,428, held in the U.S., Belgium, Germany, Italy, the Netherlands, and Turkey.

And even though many other countries have their own nuclear weapons programs, it’s still mostly a Russia and U.S. thing. 90 percent of the world’s nuclear weapons are in those two countries.

By the way, the exact number of nuclear weapons in each country is top secret. So, we’re going to be playing with estimates a lot in this video. Truth is, nobody really knows how many nuclear weapons there are in the world. Which isn’t great…

But to kinda break down these missiles even further, there are two types of weapons, strategic, and nonstrategic.

Strategic nuclear weapons are long-range and made to directly attack another country’s homeland.

Nonstrategic nuclear weapons are also called tactical nuclear weapons. They have a shorter range and are made for battlefield use.

In other words, tactical weapons are intended to win a battle, while strategic ones are used to win a war.

So tactical nuclear weapons are much smaller, and don’t get as much attention as the big city-destroying kind, but there’s a couple of problems with that, one, they’re still nuclear weapons, some of them stronger than Hiroshima.

But second, because they’re smaller, that means they’re more likely to be used.

It’s like generals are a lot less likely to launch a nuclear attack if they know it’ll trigger a mutually assured destruction scenario. But a small one, just used to win a battle…? Maaaybe not?

Like at various times Putin and Russia have threatened to use tactical nukes in Ukraine, but if they do, and that’s still a possibility… Things would get really scary really quick.

Using nukes of any kind is a threshold that you just don’t cross on any level. Or as former U.S. Defense Secretary Jim Mattis said in 2018:

“I don’t think there is any such thing as a ‘tactical nuclear weapon.’ Any nuclear weapon used at any time is a strategic game-changer.”

But in our scenario today, politics don’t matter because we are definitely going to light all these candles.

To figure out how bad the damage would be, we’ve got to figure out how much explosive force we’re dealing with and with nuclear weapons, that’s measured in yields.

The bombs the U.S. dropped on Japan during War War II had yields of around 15 kilotons and 20 kilotons each. So that was their yield.

That’s actually kinda on the small side compared to many that followed, but when you get into hydrogen bombs, you’re getting into the megatons of yield, literally thousands of times bigger.

Hydrogen bombs use a fission bomb as its trigger. The force from the fission bomb compresses hydrogen enough to fuse, giving it an almost unlimited yield.

Some of the largest bombs ever tested were hydrogen bombs, with the largest being the “Tsar Bomba.”

The Soviet Union detonated it on Oct. 30, 1961, and it had a yield of 50 megatons.

For reference, if that bomb exploded here in Dallas today, it could at least cause 3rd degree burns for a 37.3 mile radius. (60 km)

But nuclear weapons are double bad because it’s not just the stuff that got blown up, there’s also the fallout radius.

So what happens is a giant fireball is created when a nuclear weapon explodes. Everything inside the fireball vaporizes and is carried upwards, creating the mushroom cloud you’ve seen a million times.

But in that mushroom cloud all the radioactive material from the device, vaporized and mixing with the air.

Once that air cools, it condenses and forms particles, that then fall back to Earth, covering everything down below.

And not just below because the wind spreads this way further than the blast site.

So when you talk about nuclear blasts, you have to factor in the fallout because it irradiates everything to a dangerous level.

There are several physical effects caused by nuclear weapons. These include a thermal wave, a blast wave, an electromagnetic pulse, ionizing radiation released, and radioactive isotopes produced in fallout.

Just one explosion in a city can kill thousands of people immediately. Massive overpressures would destroy most structures, high temperatures would incinerate flammable materials, and intense winds would cause firestorms.

Radiation exposure would cause short and long-term illnesses and genetic health effects.

The world’s climate and agriculture production would also be severely disrupted.

So, that scenario is about just one explosion or a handful of them.

In reality, there’s no exact way to estimate the impact of one nuclear weapon.

Several variables determine its effects. Like how large the weapon is, the weather, the time of day, the geography of where it explodes, and if it explodes in the air or on the ground.

But we can make some general predictions with the limited resources we have.


So, what if all nuclear weapons were shot or dropped and exploded at the same time? What would that look like, and what would be left?

Okay, so we’re going to use data from the NUKEMAP by Alex Wellerstein. (Jason Note: on his page, he specifically requests credit: https://nuclearsecrecy.com/nukemap/faq/)

This site shows the effects of different types of nuclear bombs going off in specific locations.

For this exercise, let’s choose the W87 warhead, which has a yield of 300 kilotons.

One airborne explosion at 6,860 feet (2,091 meters) would create:

  • A radiation radius of 1,520 ft, covering an area of 0.26 square miles. (463m & .67 km²)
  • A fireball radius of 1,960 ft, covering 0.43 mi² (597m & 1.1 km²)
  • A moderate blast damage radius (5 psi) of 2.92 miles with an area of 26.9 mi² (4.7km & 69.6 km²)
  • A thermal radiation radius (3rd-degree burns) of 4.45 miles covering 62.3 mi² (7.1km & 161.3 km²)
  • A light blast damage radius (1 psi) of 8.22 miles covering 212 mi² (13.22km and 549km²)

For comparison, the bomb dropped on Hiroshima was 15 kilotons and it completely destroyed everything within a 4.4 mile radius.

So, for our exercise, let’s use the thermal radiation area of 62.3 square miles for the 300-kiloton weapon as a destruction benchmark.

Let’s imagine that all 12,700 nuclear warheads have 300 kilotons of power. Again – we’re playing with averages here.

We get an area of 791,210 square miles of thermal radiation if they all go off in the air.

Combined, that pretty much wipes out the western U.S. states of Arizona, California, Idaho, Nevada, Oregon, Utah, Washington, and Wyoming.

Or all of Mexico. Or a third of Australia.

The Earth’s surface area is around 196,900,000 square miles.

So, thermal radiation from all the 300-kiloton nukes going off at the same time would affect 0.4 percent of the Earth.

But that’s a low average yield, let’s say the average of all of them was the same as the 800-kiloton Russian Topol 22-25 missiles.

One detonated at 2,899 meters (9,511 feet) in the air would create a thermal radiation area of 148 square miles. (383 km²)

Beep bop beep boop… do the math… and for all of them going off at once would be 1,879,600 square miles of thermal radiation. (4,868,142 km²)

That’s enough to take out Alaska, California, Texas, and a few other states. Or all of India.

Also, that would be one percent of the world’s surface destroyed.

But what if there was an actual nuclear war or someone was just trying to kill as many people as possible by directing them at cities?

Around 56 percent of the world’s 8 billion population live in cities or urban areas.

That’s about 4.4 billion people.

There are also over 4,000 cities with more than 100,000 inhabitants.

While some places are bigger than others, let’s say we use three bombs for each city. To keep the math simple, let’s stick with the 4,000 number for that.

Bing bang boom… We’d use 12,000 nukes to kill more than 4 billion people and still have around 700 warheads left.

Still not enough to kill the roaches.

But what if it’s just a war between the U.S. and Russia?

Well, the Bulletin of the Atomic Scientists claims that 4,000 100-kiloton nuclear warheads would lead to the immediate death of 360 million people. At minimum.

And if a rogue AI blew all the nukes right where they’re stored?

There would be hundreds of millions of deaths, primarily in the U.S. and Russia since they account for 90 percent of the world’s nuclear weapons.

Nukes housed in submarines all exploding at the same time would create powerful tsunamis, while also killing anything within the blast radius.

One positive is that water is a good radiation blocker, so it would limit the amount escaping from the blast.

Finally, what if we just piled all 12,700 nukes in one spot and blew them up there?

Sticking with our 300-kiloton missiles, an explosion would equal 3.8 gigatons of power.

For comparison, the Chicxulub impact event was around 100 million megatons (100,000 Gt), and the Krakatoa volcano explosion in 1883 equaled around 200 megatons.

By the way, the 1815 volcano explosion of Mount Tambora in Indonesia was 10 times more powerful than Krakatau.

But Krakatau is more widely known because it erupted during the time of the telegraph, which helped spread the news more quickly.

Just doing my part to help you win bar trivia. You’re welcome.

Some of you may question that 3.8 megatons of power calculation because there could be an additive yield by combining all of them together. That’s a fair point, and more than I really need to get into in this video.

Sticking with our 300-kiloton missiles, an explosion would equal 3.8 gigatons of power.

For comparison, the Krakatoa volcano explosion in 1883 equaled around 200 megatons. Far less than our all-nuke explosion but equal to about 4 Tsar Bombas.

But the 1815 eruption of Mount Tambora was thought to be 10 times more powerful than Krakatoa, which would put it at about 2 Gigatons. Roughly half our nuclear apocalypse.

Now while both of those eruptions did have impacts on the climate – the year after Tambora was famously known as the Year Without A Summer because of all the ash – neither of them led to any drastic extinction events.

For that, we can look at the mother of all extinction events, the Chicxulub meteor impact, which has been estimated to have had 100 million megatons of explosive power, or one hundred thousand gigatons. So… slightly bigger.

Some of you may question that 3.8 megatons of power calculation because there could be an additive yield by combining all of them together. That’s a fair point, and more than I really need to get into in this video.

But the point is… would we “destroy the world?” Not really. But we’d definitely destroy the world as we know it.

Sure, some parts of the world would still be habitable, and some people would survive. But it won’t be pretty.

Radioactive fallout will be the biggest issue the world would have to deal with. It would have serious health and environmental effects.

People will breathe it in, leading to high risks of cancer. It would fall on crops, leading to food shortages.

And all the ash and dust in the air would have a cooling effect on the planet, the so-called Nuclear Winter.

In fact, famine itself within two years of a nuclear war would be more than 10 times as deadly as hundreds of bomb blasts.

o, why do we have all these nuclear weapons?

Throughout history, there’s this repeating pattern of people inventing increasingly more horrifying weapons with the goal of “ending war.”

I mean, look at the Gatling gun.

Richard Gatling thought his invention would help end conflicts because people would see how horrific the carnage was after using his gun.

We built the nuclear bomb for the same reason, to end World War II.

Then this led to mutual assured destruction between the U.S. and the Soviet Union.

But did building, testing, and exploding nuclear bombs actually work?

We’ve seen our fair share of wars in the 20th and 21st centuries, but nothing yet on the scale of World Wars II.

So, maybe the invention of the nuclear bomb finally did show us how capable we are of destroying ourselves, and it’s a line we don’t want to cross.

In the famous words of Oppenheimer:

“I guessed it worked.”

Until… you know… It doesn’t.

In fairness to Mr. Oppenheimer, if he hadn’t done it, someone else was going to, there were multiple countries working on an atomic bomb at the time. In fact, the first scientists to split a uranium atom were in Berlin in 1938.

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