Have you ever heard about the volcanic winter that killed many species and helped dinosaurs take over the Earth? More than 200 million years ago, there was a time when the Earth suffered several enormous volcanic eruptions. These eruptions were so strong that they released gases and ash into the sky, blocking out the sun and cooling the planet. Scientists call this a volcanic winter. A new study shows that these eruptions caused a great extinction that, unintentionally, helped dinosaurs become the rulers of the planet. So, let’s find out more about this study.
What happened at the end of the Triassic?
The extinction occurred about 201 million years ago, at the end of an era called the Triassic. More than 70% of the species that lived on land disappeared. With many species out of the way, the dinosaurs were able to grow, multiply, and dominate the world in the next era: the Jurassic.
For a long time, scientists have tried to understand what caused that great extinction. The main suspect has always been a giant volcanic region called CAMP (Central Atlantic Magmatic Province), which formed when the continents were joined together in a supercontinent called Pangaea.
What did scientists discover?
A group of scientists studied ancient volcanic rocks from Morocco and Canada. These rocks hold traces of the Earth’s magnetic field at that time. Thanks to that, they were able to identify five major eruptions that happened in less than 50,000 years—something very fast in the planet’s history.
Each eruption lasted less than 100 years, and they were so powerful that they filled the sky with gases like sulfur dioxide (SO₂). This gas turns into a kind of “mirror” that reflects sunlight, making the Earth cool down quickly.
Why was that so dangerous?
That sudden cooling is called a volcanic winter. Since not enough sunlight could reach the ground, plants couldn’t do photosynthesis, which means they couldn’t grow. If plants die, the animals that eat them also start to die. That’s how the whole food chain breaks down.
The first volcanic pulse released 63,000 megatons of sulfur dioxide—500 times more than a major eruption in Iceland in 1783! These winters were so cold and came so close together that ecosystems didn’t have time to recover between one and the next.
What happened in the ocean?
In the ocean, the damage was different. There, the carbon dioxide (CO₂) from the eruptions warmed the water, made it more acidic, and reduced the oxygen. That caused many marine species to also go extinct, but for different reasons than on land.
And what about the dinosaurs?
Dinosaurs already existed before these eruptions, but they were few and not dominant. When the volcanic winters wiped out many other species, the dinosaurs survived and found more space and food.
Also, scientists believe that smaller, feathered dinosaurs could adapt better to the cold and changing climate, while other larger reptiles didn’t survive. That’s how dinosaurs became the most important animals on Earth for more than 130 million years.
What can we learn from this?
This study shows that the climate can change very quickly and affect all living beings. In this case, five eruptions lasting less than 100 years each completely changed the history of life on the planet. It also teaches us that big disasters can open up opportunities for new forms of life to grow and evolve. Thanks to this great extinction, dinosaurs got their chance.
Finally, scientists used many techniques (like studying magnetism, soils, and marine rocks) to better understand what happened more than 200 million years ago. That helps us understand how climate is connected to life on Earth, even today.