The Day Everything Died

Today's video is kindly sponsored by Raid Shadow Legends. Hey, FortyTwo here. As you've probably noticed, planet Earth is home to a startling array of animals, both big and small. Lift up a rock, climb a tree, stick your head into a lake, spelunk your way into a cave. Wherever you look, life teems. But here's a mind-blowing random interesting fact for you. Despite the remarkable abundance of life all around us, it turns out that an estimated 99.9% of all the animal species that have ever existed on Earth have already gone extinct. Just as death is a normal part of life, extinction is a normal part of evolution. The quiet slipping away of species over time is known as the background extinction rate. It changes from one epoch to the next, but it's always there, no matter how good conditions are for life. But not all species loss is like the proverbial tortoise, slow and steady. Every once in a while, the extinction hair rocks up and starts gunning down unsuspected species, faster than Legolas killing orcs at the Battle of Helm's Deep. These so-called mass extinctions have occurred a total of five times in the history of our planet. No doubt you've heard of at least one of them, the Cretaceous-Paleogene extinction event that wiped out the dinosaurs 66 million years ago. But whilst that's undeniably the A-list celebrity amongst extinction events, it wasn't the deadliest, not by a long shot. That title belongs to a cataclysm so terrible, it came within a whisker of wiping out complex life on Earth entirely. Arena battles, dungeon runs and clan boss fights with an alliance of champions, it's the greatest mobile game of all time, Raid Shadow Legends. To jump straight into the action, you can use my links below to download Raid yourself to your mobile phone or PC. So recently I've been grinding out the PvP arena to try and help you get better in battles, and there's a reason for that, the Hydra. The biggest, baddest and scariest boss, the newest member of Raid's huge boss roster is an absolute beast. It has the ability to share its pain and push damage from itself onto your team and cause your champions to rot from the inside out. There's so much to discover in Raid, but personally I really enjoy the PvP arena. It's a great way to put all of my experience during the Raid campaign to good use against other players. So what's new in Raid? Well, Raid's giving away a super limited edition champion to every player in the game. Some of you might already recognise him, it's esports legend and Na'vi superstar, S1mple. Between now and January the 28th 2022, S1mple's limited edition champ is available for free to both new and old players in Raid. All you have to do is log in for seven days and he's yours. This is the best time to get started in Raid and if you use my link in the description or scan my QR code, you'll get some free resources and a free mystery champion straight away to kickstart your game. All this treasure will be waiting for you here. And remember, rewards will only be available for the next 30 days and only for new players. Once you're in, you can find me in-game under the name 42 and if you're fast, you can join my clan. It's that easy. Just click the link in the description and I'll see you in-game. Today, scientists call this catastrophe, the Permian-Triassic extinction event, but it's also known by another much more fitting name. The Great Dying. It was, quite simply, the biggest natural disaster in the history of life on Earth. The Great Dying took place approximately 252 million years ago and it was almost unimaginably deadly. When the dinosaurs' game over screen arrived on the surface of a 10-kilometre-wide asteroid that smashed into the Yucatan Peninsula with the force of 100 billion atomic bombs, 66 million years ago, 50% of all animal species on Earth at the time were deleted from existence. Now, it's hard to imagine something more destructive than an asteroid strike, but during the Great Dying, a staggering 90% of all species were eliminated. Apocalyptic doesn't even cover it. Never before or since has complex life been so close to disappearing entirely. So, here's the million-dollar question. If a giant asteroid smashing into the planet only killed off half of life on Earth, what the hell happened 252 million years ago to do away with almost all of it? The truth is, nobody knows for sure. 250 million years ago is a very, very long time and much of the evidence we would need to reach definitive conclusions have long since disappeared. Trying to figure out the identity of the ruthless killer that initiated the Great Dying is basically like investigating the oldest cold case on Earth. Luckily, like the good intellectual detectives they are, a bunch of scientists have spent the last few decades doing exactly that. Between them, they've pieced together a pretty compelling case for the prosecution of this most massive of mass murderers. One that not only explains how complex life nearly ended during the Great Dying, but that also has a surprising amount of relevance today, 252 million years later. Just before the Permian-Triassic extinction event kicked off history's most brutal bout of species-related spring cleaning, a volcanic eruption took place in what is today Siberia. When you picture an erupting volcano, you probably imagine something along the lines of Mount St. Helens in 1980. Explosive and destructive, but relatively short-lived. The volcano that erupted just before the Great Dying was a little bit different. The eruption of Mount St. Helens built up to an explosive finale over a period of a couple of months. The eruption event that coincided with the Great Dying lasted for two million years. The Siberian volcano is thought to have been caused by a mantle plume, essentially a big blob of unusually hot magma beneath the Earth's crust. About 250 million years ago, this particular mantle plume rose up from the belly of our planet and spewed forth its molten innards all over Siberia like a drunk after a vindaloo. To give you an idea of the kind of scale we're talking about here, the Mount St. Helens eruption, which was one of the largest in the entire 20th century, coughed up about 2.8 square kilometres of material. The volcanic events that took place in Siberia in the lead up to the Great Dying brought forth four million cubic kilometres of material from the depths of the Earth. That's enough lava to cover the entire planet in a layer eight metres deep. To state the bleeding obvious, that's a lot of molten rock. These eruptions represent one of the largest volcanic events ever to have taken place on Earth. But it wasn't the eruption itself that almost wiped complex life out of existence, or at least not directly. Whilst, in theory, this supervolcano produced enough lava to form a planet-wide ocean of molten death, in practice, that lava was confined to an area of seven million square kilometres in Siberia, known as the Siberian Traps. It's still there today, by the way. A vast landscape the size of Australia, built on lava fields hundreds of metres deep and over 250 million years old. But no, it wasn't lavary death that caused the Great Dying. It was the resulting chain reaction that quickly snowballed into a real-life version of the apocalypse. And it all started the same way your last beans-on-toast dinner ended, with some really bad gas. Whilst we tend to focus on the more exciting parts of volcanic eruptions, the lava, the pyroclastic flows, the holiday-hampering ash clouds, volcanoes also produce an awful lot of gas. That includes water vapour, which is, of course, harmless, but also CO2 and sulphur dioxide, which very much aren't. As trillions of tonnes of lava oozed up out of the Earth in Siberia 250 million years ago, vast quantities of sulphur dioxide, dust and ash billowed up into the atmosphere, blocking out the sun and causing global temperatures to plummet. The resulting reduction in sunlight caused massive disruption to photosynthesis in both the oceans and on land. Since the organisms found at the bottom of most food chains are photosynthesizers, like plants and algae, this sudden dip in production caused food chains to collapse, devastating ecosystems across the globe. What goes up must come down, and eventually all that debris fell back down to Earth. Dust and ash blanketed the ground and choked the air, and the sulphur dioxide, which had combined with water vapour to form acid aerosols, was washed out of the atmosphere in the form of some of the most severe acid rain ever experienced on Earth. This deadly precipitation got to work murdering whatever plant life was still left alive, whilst also contributing to a significant drop in the pH of the oceans, enough to crumble corals and melt the shells of other sea creatures clean off their backs. Then it was about time that this other volcanic gas I mentioned, carbon dioxide, joined the party. As you've probably noticed, CO2 is a potent greenhouse gas, and once the dust clouds had settled and the acid aerosols had dissipated, all that extra CO2 in the atmosphere began to do its thing, leading to an intense period of global warming. Warming that was made even worse by a monumental stroke of bad luck. You see, the Siberian Traps happened to be located on top of an extensive coal bed. As rampaging lava ignited these coal beds on an enormous scale, catastrophic levels of greenhouse gases, including carbon dioxide and methane, were released into the atmosphere. Estimates vary wildly, but by some measures it's thought the Siberian Traps eruptions contributed to the release of some 14.5 trillion tons of carbon, about 2.5 times what would be released if we burnt all the fossil fuels on Earth at the same time. As a result, global atmospheric temperatures shot up by as much as 8 degrees Celsius. Scientists today expect some fairly dire consequences if we allow global temperatures to increase just 2 degrees above pre-industrial levels. 8 degrees is practically unthinkable. And it wasn't just the air that was getting uncomfortably warm, the seas were too, with water temperatures reaching more than 40 degrees Celsius at the equator. That's about the temperature of a hot tub. Which sounds kind of nice, but remember, this particular hot tub was full of skin-melting acid and trillions of dead animals. When you start laying it all out like this, it's kind of surprising that anything managed to survive the Great Dying at all. And I haven't even finished painting this real-life hellscape yet. With plants and forests utterly decimated and acid rain pouring from the skies all over the world, far more bare earth was exposed to the elements than was normal, and so erosion skyrocketed, washing masses of nutrients into rivers and oceans. That might sound like a good thing, and it was for a bit. The nutrients triggered a brief but pronounced explosion of life. But when that life inevitably died away thanks to the increasingly inhospitable conditions, it sank back into the ocean depths, where the bacteria that fed on it suddenly found themselves as guests of honour on the biggest buffet on earth. As this bacteria proliferated, it hoovered up oxygen like a dedicated smoker after a triathlon. Combined with the fact that oxygen is less soluble in seawater at higher temperatures, this led to a huge reduction in ocean oxygen levels all around the world. Between this lack of oxygen and rising acidity from acid rain and elevated CO2 levels in the atmosphere, earth's oceans became very nearly uninhabitable. It's estimated that around 96% of all ocean-dwelling species died out. Nobody knows quite how long it took this nightmarish process to unfold. Early research suggested it might have been some 15 million years or so, but recent evidence points to a far more rapid decline, perhaps just a few tens of thousands of years. However long it took, everyone agrees that when it was over, life on earth had been all but annihilated. It's hard to get your hands on some good rock samples that span the Permian-Triassic extinction event. Much of it is either long since weathered away or buried deep beneath the ground. But the examples we do have tell a pretty bleak story, with fossil diversity simply disappearing at the boundary. Even more creepily, we also see a huge spike in fungal fossils around the time of the extinction, presumably because various fungi were having a great time chowing down on all the dead plants and animals lying around everywhere on land. Of course, not everything succumbs to the great dying. A few incredibly tenacious species manage to adapt to the almost unimaginably hostile conditions. One plucky beastie that made its way through this shitstorm was Lytrosaurus, a proto-mammal that was a bit like a cross between a lizard and a pig. Now I know what you're thinking, Christ, that's ugly. But be careful, you're insulting part of your own family. Whilst we humans aren't direct descendants of these magnificent creatures, they do make up part of our evolutionary tree. They're synapsids, just like we are. And every other mammal in existence, for that matter. Thank God those ugly bastards made it. Thanks for watching.