Chicxulub occurred 66 million years ago. That is, the asteroid that extinguished the dinosaurs, collided with the planet Earth 66 million years ago. It was 12 miles and fell into what is now known as the Yucatan peninsula in the Gulf of Mexico. The collision was the cause of the mass extinction of the Cretaceous-Paleogene, which eliminated more than 75% of plants and animals – including dinosaurs – from the planet.
This collision with the Earth had global consequences as it released massive amounts of dust, sulfur and carbon dioxide into the atmosphere. The first two formed a cloud that reflected sunlight and drastically reduced the temperature of the planet. But now, a new study published in the Geophysical Research Letters, concluded that the release of sulfur was three times higher than previous research had claimed – so the cooling of the Earth was even more drastic than previously thought.
Joanna Morgan, a geophysicist at Imperial College of London and co-author of this study, told the American Geophysical Union website that “many climate models cannot currently see all the consequences of the impact of Chicxulub, largely because of the uncertainty about the amount of gas which was released”, adding that the team that led the investigation wanted to” revisit this event and refine the collision model to better understand its immediate effects on the atmosphere”.
For this study, the physicists used a code that simulated the pressure of shockwaves created by the impact, in order to estimate the amount of gas released. They worked with several variables, such as the composition of the vaporized rocks, to reduce the uncertainty of the calculations. They concluded that the asteroid released approximately 325 billion tons of sulfur and 425 of carbon dioxide into the atmosphere, more than ten times the global CO2 emissions in 2014.
The major difference between this new study and the previous ones is related to the method. The researchers took into account only the gases that were released into the atmosphere with a minimum speed of one kilometer per second. The gases with lower speeds did not reach a sufficient altitude to remain in the atmosphere and influence the climate, but the oldest investigations integrated in the calculations all the sulfur and CO2 released.
Still beyond the speed of the gases, the authors of the study innovated still as far as the angle of impact of the asteroid. Previous studies mentioned 90 degrees; this admits that the asteroid collided with the Earth at a 60-degree angle, which led to a higher emission of sulfur.
In turn, released sulfur has blocked sunlight and changes in ocean circulation have devastated the entire terrestrial flora and marine biosphere. This new study will help researchers calculate the amount of gases emitted into the atmosphere during other similar events.