Asteroid Impact That Killed The Dinosaurs Cooled Earth's Climate More Than Earlier Thought


The asteroid impact popularly attributed for the extinction of the dinosaurs about 66 million years ago released more climate-changing gases into the atmosphere than previously believed.

In a new study, researchers made a more refined estimate on the amount of sulfur and carbon dioxide that were released into the Earth's atmosphere from vaporized rock immediately after the Chicxulub asteroid struck Earth.

Ten Times More Than Annual Global Human Emissions

It was earlier estimated that the amount of carbon dioxide and sulfur that were released when the asteroid impacted Earth led to the average surface air temperature of the Earth to drop by up to 26 degrees with the cold temperatures lasting for at least three years following the asteroid impact.

Researchers estimated that the amount of gas that was ejected into the atmosphere was three times the amount suggested by previous estimates, which implies that the ensuing period of cool weather after the Chicxulub event was colder than previously thought.

For the new study, researchers used a computer code to simulate the shock waves' pressure. With a better understanding of the composition of the Earth below the crater and the impact angle of the asteroid based on new data from exploration of the Chicxulub impact site, the researchers found that the asteroid could have instantly released around 420 gigatons of carbon dioxide and 300 gigatons of sulfur into the atmosphere, which is 10 times more than the annual amount of carbon dioxide humans worldwide produce per year.

"We estimate that 325 ± 130 Gt of sulfur and 425 ± 160 Gt CO2 were ejected into the atmosphere at velocities > 1 km/s," the researchers wrote in their study, which was published in the Geophysical Research Letters.

"These numbers have to be used in global climate models to quantify possible changes of solar irradiation, surface temperature, and duration of stressful conditions for biota."

Better Estimates

An earlier study that modeled the Earth's climate after the impact estimated that only 100 gigatons of sulfur and 1,400 gigatons of carbon dioxide were released when the asteroid collided with Earth.

Study researcher Natalia Artemieva from the Planetary Science Institute in Tucson, Arizona said that the methods used in the new study ensured that only the gases that were ejected upwards with a velocity of at least 2,200 miles per hour were included in the calculations. Those that were ejected at slower speeds did not reach a high enough altitude to remain in the atmosphere and influence the climate.

The older models did not have much computing power and assumed that all of the gas entered the atmosphere, which posed a problem with accuracy.

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