With the help of a series of "evidence", he "solved" the biological "mass murder" 252 million years ago

The mass extinction event during the Permian period caused the extinction of more than 90% of life on Earth. It was the most serious of the five global disasters in Earth's history and more devastating than the disaster caused by the giant asteroid that caused the extinction of the dinosaurs.

The most plausible explanation proposed so far for the mass extinction is that volcanic activity in a region known as the Siberian Shield (a large area in modern-day Russia about the size of Australia) released carbon dioxide, causing global warming, acid rain, and ocean acidification.

Sun Yadong

However, according to a new study recently published in the journal Science, a giant El Niño effect may have played a more critical role. The researcher who made this new discovery is Professor Sun Yadong of the State Key Laboratory of Biogeology and Environmental Geology at China University of Geosciences (Wuhan). This is his fourth Science paper and his favorite one. "Because its significance is important enough to inspire everyone to more closely combine the changes in modern society with biological extinction."

Conducting “unique” scientific research

Sun Yadong has been very successful in scientific research. In 2004, he was admitted to China University of Geosciences (Wuhan) and obtained a doctorate degree. After studying and working in Germany for 9 years, he returned to his alma mater in 2022. So far, he has published 4 Science papers: at the age of 24, he published his first Science paper as the second author, at the age of 27, he published his first first-author research report, at the age of 28, he published his first review, and at the age of 39, he published his first research article.

Sun Yadong doesn't like to imitate or follow others, he only does what he is interested in. Perhaps this is why he has grown so quickly in scientific research, because passion can overcome all difficulties.

When he was in high school, he was obsessed with ancient buildings and even wanted to work in the architectural design industry to express himself through unique architectural works. But by chance, Sun Yadong did not become an architect and instead plunged into the world of science.

Permian sedimentary rock layers discovered in northern Italy

Even though he deals with rocks, minerals, and ancient organisms every day, Sun Yadong still insists on his "unique" pursuit of scientific research. The characteristics of geobiology provide him with a never-ending picture of exploration. To some extent, geobiology is a subject that is always in progress - because no one can completely uncover the whole truth of hundreds of millions of years ago. "This is what I am most interested in. With the advancement of science and technology, we know a lot, but we also don't know a lot. I want to dig into those unknown things."

When he was young, Sun Yadong liked to read detective novels. He was fascinated by "Murder on the Orient Express" by British mystery writer Agatha Christie. The handkerchief, dagger, unburned paper scraps, scarlet nightgown... all connected the evidence at the murder scene. He also tried to solve the mystery of who the real murderer was.

Be careful to verify. There are actually similarities between doing scientific research and solving cases. Just like the great detective Poirot in "Murder on the Orient Express", Sun Yadong used a series of "evidence" to clearly and orderly "solve" the "great murder" that occurred 252 million years ago.

All species have their limits.

The mainstream view in the scientific community is that the mass extinction at the end of the Permian period was related to the large-scale volcanic eruption in Siberia. After more than 4 billion years of evolution, life on Earth has become extremely resilient, and many species can adapt to very harsh environments. In fact, volcanic eruptions similar to Siberia have occurred many times in Earth's history, but none of them can compare to the scale of the mass extinction at the end of the Permian period.

"It is extremely difficult to wipe out life on Earth. This means that the mechanism behind the end-Permian mass extinction may be more complicated, and the 'mastermind' may be someone else," said Sun Yadong. If the end-Permian mass extinction is likened to a chaotic murder case, it is crucial to find out the culprit.

In 2018, Sun Yadong was still an assistant researcher at the University of Erlangen-Nuremberg in Germany. One of his research topics was to use oxygen isotopes from microfossils in deep-sea sediments to reconstruct the temperature of seawater. When reconstructing the temperature changes in the Tethys Ocean, he keenly noticed that the temperature change data on the east and west edges of the ocean were inconsistent. Combining the knowledge of modern oceanography, Sun Yadong boldly speculated that the difference in sea temperature may be caused by the El Niño phenomenon in deep time (concept of geological time).

Since then, Sun Yadong has not taken the time to delve into this hypothesis. It was not until the spring of 2021, when he had a lot of free time due to the pandemic, that his previous conjecture about El Niño came back to his mind. In order to prove the relationship between El Niño and the end-Permian mass extinction, he had to come up with two pieces of evidence: sedimentary geochemical proxy indicators and complex Earth system science model simulations.

Sun Yadong previously worked on ocean temperature indicators. By analyzing oxygen isotopes in the fossilized teeth of tiny organisms called conodonts, he derived the specific scale of climate warming at the end of the Permian. After further studying the temperature records of conodonts around the world, Sun Yadong found that the temperature gradient between low-latitude and mid-latitude regions dropped significantly at the end of the Permian.

However, analyzing indicators alone cannot tell the story clearly, nor is it convincing enough. "Indicators can only provide a few data points in a limited geographical location. To see the full picture, you need to use supercomputer simulations." Through an acquaintance, he met Alexander Farnsworth, a senior researcher at the University of Bristol in the UK who specializes in using comprehensive modeling methods to study the role of ocean-air circulation in climate change.

The supercomputer simulation took a year and a half, and the analysis took almost a year. Under their "careful verification", the truth of the mass extinction gradually surfaced. They pointed out that the giant ocean warming El Niño event was the key factor in the largest mass extinction on Earth about 252 million years ago.

El Nino "roasts" the world

"During the end-Permian extinction, El Niño lasted longer, often causing persistent large-scale hot and dry weather, followed by short, sudden rainfall. Such a climate is everywhere, making it difficult for any species to adapt," said Sun Yadong. This also explains why there is a time difference between the extinction of land species and the extinction of marine species during the mass extinction.

From 2023 to 2024, wildfires occurred in many places such as the United States and Canada, which are all related to the current global warming background. These disasters have caused some small cities to relocate, and the strong El Niño has also led to the degradation of the Amazon rainforest. "Now people pay less attention to it because the scale of the current disasters is small. Looking at these short-term disasters separately, it seems that they are not aware of their harmfulness. However, the compound effect of the increase in interannual climate variability and the background climate warming will have devastating consequences. The mass extinction at the end of the Permian period is a lesson for us." Sun Yadong said.

Sun Yadong's research found that frequent wildfires, coral death and forest degradation all occurred during the end-Permian mass extinction. "I am haunted by the thought of their relationship with biological extinction. Will future El Niños continue to intensify under the background of human intervention? If they become stronger and more frequent, this may affect various ecosystems around the world. Although life will bloom again after the mass extinction, the Permian mass extinction eventually led to the rise of dinosaurs as dominant species, and the Cretaceous mass extinction led to the rise of mammals and humans. But this is a harsh reminder: all species have their limits." Sun Yadong said frankly.