Earth’s most devastating extinction was triggered by Siberian volcanic eruptions 250 million years ago.
Hardly any species survived the Great Permian Extinction, known as the “Great Dying”, which lasted one million years.
The event wiped out more than 95 percent of marine life and 70 percent of land animals.
Catastrophic environmental changes also resulted from the period.
But scientists have not known what it was that wiped out life – until now.
Geoscientists have now unearthed exactly why the eruption was so devastating.
In a new research paper, geoscientists claim the million-year long eruption released chemicals into the atmosphere that were so toxic they essentially stripped the Earth of its ozone layer.
This led life on our planet to be exposed to deadly solar radiation which would have massively increased the risk of cancer and caused plant life to die off – leading to the death of animals through lack of food and poor breathing conditions.
The researchers analysed Siberian rocks from between the earth’s crust and mantle that date back to the time of the extinction.
They found the rocks contained an extremely high concentration of deadly chemicals such as bromine, iodine, and chlorine.
The toxins ate away at the ozone layer, leaving animals on our planet exposed to the deadly elements from space.
Study lead author Michael Broadley said: “We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth’s atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction.
“The scale of this extinction was incredible.
“Scientists have often wondered what made the Siberian Flood Basalts so much more deadly than other similar eruptions.”
Life on Earth would be extremely different to how we know it at the time of the volcanic eruption 250 million years ago.
Dinosaurs had not even come to be at this point. Instead the Earth was dominated by reptiles – which were the precursors to the dinosaurs who came about 10 million years later.
The planet would have been home to large herbivores known as captorhinomorphs, which measured between two and three-metres in length (7 to 10 feet) and were the first grouping of reptiles.
The ocean was dominated by bony fish with fan-shaped fins and thick, heavy scales.