Previous: 3 Animals That Breathe Through Their Butts
Next: SciShow Talk Show: Jimmy Henderson & The Red Eyed Skinks



View count:594,223
Last sync:2022-12-29 21:45
There are a lot of nuclear weapons on Earth, so many that we often say it’s enough to “destroy the world several times over.” But could we? Well, that depends on what you mean. matter what you mean, probably not. The Earth is pretty sturdy and people are pretty good at surviving and even after all this time and technology, our biggest weapons are pretty puny on a universal scale.
Messages from our Subbable Subscribers
Hey best friend, I love you. - Justice Hitchcock
I love Milly Fox and look up to Adam Savage. - Miles from Sydney, AUS
I love you, Nicholas. - Marisse M.
Go Science!!! - Claire
Don't Forget To Be Awesome means Don't Stop Believing ;) #Glee - monacolonia
This time that we had I will hold forever! #Glee - monacolonia
Live long and prosper. - Christie Nel
Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Justin Ove, Justin Lentz, David Campos, Chris Peters, and Fatima Iqbal.
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:

Or help support us by becoming our patron on Patreon:
Looking for SciShow elsewhere on the internet?

TNT Equivalence
Nuclear Winter:
(text: QQs: could we destroy the Earth?)

Hank: So we talk about how we, the people of Earth, have the ability to destroy ourselves in a way that most species don't. What we're generally talking about when we say this is nuclear weapons and how we like "have enough nuclear weapons to destroy the Earth many times over." Well first of all good news, we couldn't do that. In terms of pure destructive force, the entire nuclear arsenal of every country on Earth, mostly concentrated in the US and Russia, is about 7,000 megatons, the equivalent of 7 [billion] tons of TNT.

Now the Chicxulub meteor impact didn't destroy the Earth or all life on Earth and it was about 14,000 times more powerful than that. 14,000 times more power than all the nuclear weapons on Earth. We truly are puny humans.

Even the relatively mild 1883 eruption of Krakatoa was four times more powerful than the most powerful fusion bomb ever designed. Basically, if every nuclear weapon on Earth simultaneously exploded right now... we would have some bad stuff happen, there would be like an increase in localized radiation, and a number of unfortunate deaths, but overall we might actually live in a safer world, especially because those bombs right now are underground in remote areas for the most part.

The most dangerous possibility and where the idea of the deadly apocalyptic nuclear winter comes from is if those bombs are actually used on cities. The bombs themselves of course would have a significant impact but the more important bit is the resulting thousands of firestorms.

Now firestorm sounds just kind of like a hyperbolic word for like a really bad fire, but it is not that. Firestorms happen when a fire is intense enough to create its own weather pattern of increased winds, which further drive the burning and destruction and they shoot soot and ash way up into the atmosphere. This is exactly what happened in Hiroshima and Nagasaki.

If that happened thousands of times around the Earth all at once, atmospheric models indicate that yes, indeed, it would be very bad. We're talking global decreases in temperatures up to 25 degrees Celsius for a few months, and then up to 6 degrees Celsius for a number of years. That would be very bad news for all of the people and also the ecosystems that we depend on. Also, having the majority of city-dwelling humans killed and all of the city-based infrastructure destroyed would be... you know, not good.

However, and I'm not saying I want to test this out, I do have confidence that some people would survive, though they would survive in a world without YouTube and air conditioning, so really, what's the point?

Thank you for asking and thank you if you are one of our Patrons on Patreon who keep these answers coming. If you want to submit questions to be answered or get these quick questions a few days before everybody else, you can go to, and if you just want to keep getting smarter with us, you can go to and subscribe.