The disaster that almost killed off the dinosaurs could happen again

(NLĐO) - The most devastating mass extinction on Earth occurred just a few million years before the dinosaurs appeared. The culprit was the "super El Niño".

A team of scientists from China, the UK, Germany, and Austria, led by geologist Yadong Sun from the Chinese University of Earth Sciences, has developed models of ocean currents and the atmosphere 252 million years ago to learn about the most catastrophic events that occurred before the dinosaurs appeared.

The catastrophic event mentioned is the Permian-Triassic extinction event, which nearly halted the evolutionary path of life on Earth. Fortunately, a few survivors made it through.

This disaster wiped out approximately 96-97% of marine species and over 70% of land species.

An ancient stratigraphic cross-section reveals a barren surface at the transition from the Dipterocarpus to the Triassic periods, suggesting a super El Niño once existed - Photo: LEEDS UNIVERSITY

The ancestors of the dinosaurs were fortunate to survive this event, turning the devastated world into an opportunity to begin an age of monsters that lasted for three epochs: the Triassic, the Jurassic, and the Cretaceous.

With just a little more bad luck, dinosaurs wouldn't have appeared on Earth, and the planet might not even be alive today.

What triggered the Dipsaccidal-Triassic mass extinction is still not entirely clear.

According to evidence gathered from around the world, 252 million years before the "doomsday scenario," the Earth's biosphere was very vibrant.

Diverse aquatic life flourished in a superocean surrounding a single supercontinent. On that supercontinent, coniferous trees grew into dense forests as the four-legged ancestors of modern mammals, birds, and reptiles frolicked beneath the canopy.

Everything seems fine, but something is silently eroding life.

Of the evolving families of four-legged animals, only 10% will go on to produce future generations. Millions of years later, marine species will begin to disappear one by one, until only about one-fifth of the original species remain.

Never before has the world witnessed such a massive loss of life, leading researchers to question why this period is so toxic.

Scientists have discovered massive layers of igneous rock in what is now Siberia, indicating a prolonged period of volcanic activity spanning the transition between the Dichotomous and Triassic periods—exactly 252 million years ago, a remarkable coincidence.

Putting other evidence together, the research team suspects a series of chain effects from the continuous volcanic eruptions.

This process can strip or severely damage the ozone layer, releasing enough carbon dioxide to warm the atmosphere, while the growth of bacteria floods the oceans with oxygen before absorbing it again.

By analyzing the oxygen isotope ratios in the fossil teeth of ancient marine organisms, researchers found evidence of climate changes similar to the El Niño phase of today's Southern Oscillation.

El Niño events cause many problems for humanity today, such as torrential rains in some places and droughts in others, enough to cause difficulties for the biosphere even if they only last 1-2 years.

However, at the end of the Dichotomy, there was a prolonged and intense super El Niño period that lasted for centuries.

Models suggest this could easily cause a mass extinction, or even an apocalypse.

That could happen again if humanity continues to emit massive amounts of greenhouse gases, "mimicking" the effects of supervolcanoes of the past.

The Earth could once again restore its biosphere thanks to the rare species that survive, much like how dinosaurs came into existence. However, clearly no one wants that because, first and foremost, most life would be wiped out if a super El Niño event were to repeat.

Source: https://nld.com.vn/tham-hoa-khien-khung-long-suyt-khong-ra-doi-co-the-lap-lai-196240915104318756.htm