The asteroid that killed the dinosaurs cooled Earth’s climate • Earth.com
Researchers are now learning that the asteroid released far more climate-altering sulfur gas into the atmosphere than previously realized.
11-01-2017

The asteroid that killed the dinosaurs cooled Earth’s climate

The asteroid that formed the Chicxulub Crater, named after the Mexican village that it struck near its center, wiped out over half of the species on Earth including the dinosaurs. Researchers are now learning that the asteroid released far more climate-altering sulfur gas into the atmosphere than previously realized.

To estimate the amount of sulfur and carbon dioxide released during the Chicxulub event, the scientists used computer simulations to represent the pressure of the shock waves created by the asteroid’s impact. They changed variables such as the angle of the asteroid as it struck to reduce the uncertainty of their calculations.

The research team found that more than three times as much sulfur may have entered the air compared to what previous models indicated. This suggests that the weather on Earth after the impact may have been much colder than previously thought.

The new study shows that the impact likely released 325 gigatons of sulfur and 425 gigatons of carbon dioxide into the atmosphere. In contrast, a previous investigation had assumed 100 gigatons of sulfur and 1,400 gigatons of carbon dioxide were expelled as the asteroid struck the planet.

The dust and sulfur that shot out into the atmosphere formed a cloud that reflected sunlight and drastically reduced temperatures by as much as 47 degrees Fahrenheit, according to the experts, and the freezing temperatures persisted for up to three years.

The new research supports the theory that the impact played a significant role in the Cretaceous-Paleogene extinction event that eradicated nearly three-quarters of Earth’s plant and animal species. Study co-author Joanna Morgan is a geophysicist at Imperial College London.

“Many climate models can’t currently capture all of the consequences of the Chicxulub impact due to uncertainty in how much gas was initially released,” said Morgan. “We wanted to revisit this significant event and refine our collision model to better capture its immediate effects on the atmosphere.”

According to climate scientist Georg Feulner, the new findings could ultimately help scientists better understand how Earth’s climate radically changed in the aftermath of the Chicxulub event.

“The key finding of the study is that they get a larger amount of sulfur and a smaller amount of carbon dioxide ejected than in other studies,” said Feulner. “These improved estimates have big implications for the climatic consequences of the impact, which could have been even more dramatic than what previous studies have found.”

The research is published in Geophysical Research Letters, a journal of the American Geophysical Union.

By Chrissy Sexton, Earth.com Staff Writer

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