The Chicxulub asteroid impact that many believed wiped out the dinosaurs released far more climate-altering gas into the atmosphere than originally thought, scientists have revealed.
Scientists in a new study have refined the estimate as to how much sulfur and carbon dioxide gas were ejected into the atmosphere from vaporized rocks immediately after the Chicxulub event and now believe that three times as much sulfur may have entered the air than previously believed.
The new study supports the hypothesis 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.
“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,” Joanna Morgan, a geophysicist at Imperial College London in the United Kingdom and co-author of the new study, said in a statement. “We wanted to revisit this significant event and refine our collision model to better capture its immediate effects on the atmosphere.”
This discovery could ultimately aid scientists in better understanding how Earth’s climate radically changed in the aftermath of the asteroid collision.
The Chicxulub impact occurred 66 million years ago when an asteroid about 12 kilometers wide crashed into the Earth near what is now the Yucatán peninsula in the Gulf of Mexico, potentially triggering the Cretaceous-Paleogene extinction event.
The collision threw massive amounts of dust and sulfur into the atmosphere, forming a cloud that reflected sunlight and dramatically reduced the Earth’s temperature.
Previous estimates found that the Earth’s average surface air temperature may have decreased by as much as 26 degrees Celsius and that sub-freezing temperatures persisted for at least three years after impact.
In the current study, the researchers used a computer code to simulate the pressure of the shock waves created by the impact to estimate the amounts of gases released in different impact scenarios.
They changed variables, including the angle of the impact and the composition of the vaporized rocks to reduce the uncertainty of their calculations.
The new simulations show that the impact likely resulted in approximately 325 gigatons of sulfur and 425 gigatons of carbon dioxide being released into the atmosphere, more than 10 times the global human emissions of carbon dioxide.
The scientists used methods that ensured that only gases that were ejected upwards with a minimum velocity of one kilometer per second were included in the calculations.
They also based their model on updated estimates of the impact’s angle, estimating that the asteroid hit at an angle of approximately 60 degrees.
The British Journal Editors and Wire Services