An asteroid impact, not volcanic activity, killed the dinosaurs, according to a new study.
For decades, scientists have gone from one side to another about exactly what caused a mass extinction event 66 million years ago, which destroyed approximately 75% of all life on Earth, including all large dinosaurs. Some have thought that volcanic activity could be to blame, but a new study shows that a giant asteroid impact was the main culprit.
Scientists have known that the impact, which created the massive Chicxulub The impact crater (located in what is now the Yucatan peninsula in southeastern Mexico) was an important factor that contributed to this extinction event. But the volcanic activity that occurs at around the same time has raised questions about what could have been the main factor that changed conditions on our planet that led to the disappearance of creatures from Earth.
In a new study, researchers at Imperial College London, the University of Bristol, and University College London have shown that the impact of asteroids, not volcanic activity, was the main reason why approximately 75% of life in Earth perished at that moment, and it did. so it significantly interferes with Earth’s climate and ecosystems.
“We showed that the asteroid had a winter shock for decades, and that these environmental effects decimated dinosaur-friendly environments. By contrast, the effects of intense volcanic eruptions were not strong enough to substantially disrupt global ecosystems “, the principal investigator Alessandro Chiarenza, who carried out this work while studying for his doctorate in the Department of Earth Sciences and Engineering at Imperial, he said in a statement. “Impact winter” means a semi-permanent “winter” created when the particles that block sunlight are expelled into the atmosphere after an impact. “Our study confirms, for the first time quantitatively, that the only plausible explanation for the extinction is the impact of the winter that eradicated dinosaur habitats worldwide.”
To reach this conclusion, the researchers modeled how Earth’s climate would be expected to respond to two separate possible causes of extinction: volcanism and asteroid impact. In these mathematical models, they included environmental factors such as rain and temperature, which would have been critical for the survival of these species. They also included the presence of gases and particles that block sunlight and carbon dioxide, a greenhouse gases.
“Instead of just using the geological record to model the effect on climate that the asteroid or volcanism could have caused worldwide, we pushed this approach one step further, adding an ecological dimension to the study to reveal how these climatic fluctuations affected seriously to ecosystems. ” Senior coauthor Alex Farnsworth, a climatologist at the University of Bristol, added in the same statement.
With these models, the team discovered that the giant asteroid hitting our planet would have released huge amounts of gas and particles into terrestrial atmosphere, blocking the sun for years and years. This effect would have created a kind of semi-permanent winter on Earth, rendering the planet uninhabitable for most of its inhabitants.
Now, while the team discovered that the impact of asteroids is the main factor in making Earth uninhabitable for most animals, they also discovered that volcanic activity could have helped life recover over time, a conclusion scientists have drawn before.
They discovered that while volcanoes release gases and particles that block sunlight, which would have helped block the sun in the short term, they also release large amounts of carbon dioxide which, because it is a greenhouse gas, is it would have accumulated in the atmosphere and heated the planet.
So, as the researchers suggest in this paper, while the devastating winter caused by the asteroid killed most of life on Earth, over time, the warming effect created from volcanic greenhouse gases could have helped to restore life in habitats.
“We provide new evidence to suggest that volcanic eruptions occurring around the same time may have reduced the effects on the environment caused by the impact, particularly by accelerating the rise in temperatures after the winter impact. This warming induced by the volcanoes helped increase the survival and recovery of animals and plants that were made through extinction, with many groups expanding immediately afterward, including birds and mammals, “added Chiarenza.
This work was published June 29 in the Proceedings of the National Academy of Sciences magazine.
Email Chelsea Gohd at [email protected] or follow her on Twitter @chelsea_gohd. Follow us on twitter @Spacedotcom and in Facebook.
