Be glad you weren't alive for the Permian-Triassic Extinction.
No human was - it happened 250 million years ago. But there was plenty of life. The Earth was populated with thousands of species of fish and land animals and insects.
If you're imagining Jurassic Park, it wasn't that. It was Earth 20 million years before. There were big animals lumbering around, but they don't spark the imagination like a T Rex. Michael Chrichton didn't write a bestseller about "Permian Park", where they brought a Lisowicia bojani back to life. (That's the largest animal you'd find at the time. It looked like a cross between a hippo and a tortoise.)
But the era is famous for one thing: how it ended. The Permian-Triassic Era suffered the most severe mass extinction in Earth's history. Nearly all life in the ocean was wiped out -- 96% by some estimates. And 70% of all land animals. It actually cleared the way for the age of the dinosaurs. It's known as The Great Dying.
Obviously, any event called "The Great Dying" is not something you want to be a part of. And scientists are trying to understand it to make sure it doesn't happen again.
The trigger of the Permian-Triassic Mass Extinction was a volcanic eruption. This might bring to mind a single mountain with lava erupting from its summit. But this was much worse. We're talking about an entire region the size of modern day Australia that was entirely volcanic rock. It's called the Siberian Traps. It still exists today (yes, in Siberia), now just vast stretches of hardened basalt rock. But 250 million years earlier, the region spewed huge volumes of lava through massive cracks in the Earth's crust across a staggering 2.7 million square miles.
The carbon emissions released from this massive volcanic eruption -- particularly CO₂ and methane -- filled the atmosphere. Normally, sunlight that warms the Earth is reflected back into space as infrared radiation. But this shield of carbon emissions had the diabolical effect of letting the light in, so the Earth still gets warm, but stopping any infrared to escape, trapping the heat like a thermal blanket. If this sounds familiar, it's because we're warned about it constantly. This is the Greenhouse Effect.
The carbon emissions from the Siberian Traps covered the planet and led to ocean acidification and toxic air and unbearable heat. Just about every living thing died. It was catastrophic.
Strange to consider that toxic world is the same Earth we're standing on right now. Obviously the planet recovered. How long did it take? Scientists would expect the recovery -- for the Earth's temperatures to return to pre-volcanic levels -- to happen in about 100,000 years. Long enough that none of us would survive to see the end, but actually short in geological time. 100,000 years is long enough for rainwater to dissolve silicate rocks and pull CO2 from the atmosphere. It's long enough for the oceans to slowly absorb CO2 from the atmosphere (just this process takes tens of thousands of years). And, as the climate stabilizes and photosynthesis returns, it's long enough for life to re-emerge.
But this leads us to the mystery: the toxic world of the Great Dying lasted five million years.
Scientists have been unable to pinpoint why super-greenhouse conditions persisted so long. Until now.
A new study published this month (July 2025) by the University of Leeds and the China University of Geosciences answers the mystery. And the answer they find is a critical warning to us, 250 million years later.
We're probably sick of hearing how important rainforests are to stopping the greenhouse effect. Turns out, it's true. These massive areas of dense forest perform what's called "carbon sequestration" -- they remove carbon dioxide from the atmosphere and, simply put, turn it into food. The team of international researchers behind this new study found that the rainforests of the Permian-Triassic Era basically disappeared, leading to the significantly prolonged period with toxic CO2 levels.
The paper's lead author, Dr Zhen Xu, called the Great Dying, "the only high temperature event in Earth's history in which the tropical forest biosphere collapses, which drove our initial hypothesis. Now, after years of fieldwork, analysis and simulations, we finally have the data which supports it."
There's a tipping point. If the Earth loses a certain amount of rainforest, it just can't recover. Not for millions of years, anyway. When carbon emissions are too high, the natural machine that clears the air of CO2 needs to be in overdrive -- we need more rainforest, not less. The obvious question is, are we heading into that same crisis today?
In the Permian-Triassic Era the map of the globe looked very different -- well, there was one big difference. All the land was in one piece -- there was only one continent. We call it Pangaea (not sure why we have to name it, like it's a country we may visit, but there it is). Back then, the rainforests were along the equator.
Today, the rainforests are still near the equator but obviously broken up in different areas. Namely, the Amazon, the Congo, parts of Central America, and Southeast Asia.
Also today, the rainforests are disappearing. Because we're getting rid of them. We clear them to raise cattle, or for soy plantations. We clear them for logging. We clear them for mining. Over the last 50 years, over 1.2 million square miles of tropical rainforests have been lost. That's essentially the size of Western Europe.
At the same time, carbon emissions continue to raise global temperatures. The 8 years between 2015 and 2023 were the hottest on record, with 2023 being the hottest year in recorded history.
The recent study of the Permian Triassic Era proves that losing rainforests makes survival on Earth impossible for a devastatingly long time. If we stay on the same trajectory, 250 million years from now, some new form of life on Earth may look back on our time and say, "glad we weren't part of that mass extinction". Maybe they'll call it the "Second Great Dying".
Of course, we won't let that happen. We're smarter than a Lisowicia bojani.