First of all, it is safe to say that detonating the world's arsenal of nukes would be a Very Bad Idea.
A nuclear confrontation involving 100 or so warheads would plunge the world into a nasty nuclear winter. This would involve years of winter-like temperatures and extreme levels of crop failure, sending the global food system into a tailspin and creating unprecedented levels of famine. As few as five could drag us into a nuclear autumn, less severe, sure, but still pretty devastating. As a result, we could lose 20 to 80 percent of global rainfall and up to 1 billion lives.
Now, if we consider the world's entire nuclear stock, you are looking at around 15,000 warheads. The US and Russia both possess a little under 7,000 each, with the rest split unevenly among the remaining nuclear powers – the UK, France, China, India, Pakistan, Israel, and North Korea. It's fair to say that these weapons could do quite a lot of damage.
In case you are wondering what level of destruction can be done with 15,000 nukes, you will be pleased to know that YouTube channel Kurzgesagt – In a Nutshell has your back. In an animation posted on Sunday, they answer the question, "What would happen if all the world’s nuclear bombs were detonated at once?"
The answer is a lot.
According to scientists consulted by the host of the channel, it takes just three nuclear warheads to destroy one of the planet's 4,500 cities. This means that even after you have taken out every urban area of 100,000 or more people, you have 1,500 warheads left over.
If, instead, you decide to put all your nukes in one basket and drop that basket in the Amazon, you could unleash an explosion with the force of 3 billion tons of TNT, according to the host. That is equivalent to 15 Krakatoa 1883 eruptions, the most powerful volcanic eruption on record.
It would trigger a 50-kilometer (30-mile) fireball that would destroy all within a 3,000-kilometer (1,800-mile) radius of the blast. This would generate a series of pressure waves that would circle the world in the following weeks. Meanwhile, a mushroom cloud would extend to the upper levels of the Earth's atmosphere and millions of tons of incinerated material would be catapulted into the skies.
A (relatively) small crater 10 kilometers (6 miles) across would mark the site of the explosion, while the entire continent of South America would be engulfed in extreme wildfires that would make the Californian flames of last summer (the deadliest and most destructive in history) look minute in comparison.
But this is when the "unpleasant part" begins, the host says. Because this is when extreme levels of radiation would do their damage, killing living things. Everywhere from the crater to hundreds of kilometers downwind would be simply uninhabitable, while the rest of the planet would be doused in the fallout carried into the atmosphere by the mushroom cloud. The world would be plunged into a nuclear winter.
Still, we are told, "human life will go on". It just won't be very nice.
For an explanation of what would happen if we put every bit of uranium on Earth into a nuclear bomb and watched it burn, check out the video here.
[H/T: Daily Dot]