Scientists Share Theories About ‘Snowball Earth’

First Posted: Mar 24, 2017 05:08 AM EDT

George RR Martin may be the one who wrote about ice and fire. But as it turns out, a perfect storm of the same materials may have led to "snowball Earth." This phenomenon is considered to be a "once-in-a-billion-year event" and caused the largest glaciation event to ever happen on the planet.

According to the research published in the Geophysical Research Letters, researchers pinpointed the start of the Sturtian snowball Earth even around 717 million years ago. At the time, a huge volcanic event devastated a large area of the planet as massive as from present-day Alaska to Greenland. However, Harvard professors Francis Macdonald and Robin Wordsworth thought this is not the case.

Macdonald, an associate professor of the Natural Sciences in Harvard's Department of Earth and Planetary Sciences, shared, "We know that volcanic activity can have a major effect on the environment, so the big question was, how are these two events related?"

At first, Macdonald's team thought that basaltic rocks interacted with CO2 in the atmosphere and caused the world's cooling. However, if that were the case, cooling would have happened over millions of years. Thus, he turned to Wordsworth to answer the question: Could aerosols from volcanoes have rapidly cooled the planet?

Under the right conditions, Wordsworth said that it can. While large volcanic areas can erupt, these types of eruptions happen over and over again. Nonetheless, they are not always associated with cooling events -- there has to be something different.

Geological studies from the region showed that these volcanic rocks erupted through sediments that are rich in sulfur. When pushed through the atmosphere during eruption, they turn into sulfur dioxide that can block solar radiation when they reach the upper layers of the atmosphere.

Harvard's School of Engineering and Applied Sciences noted that this same phenomenon happened in 1991 after the eruption of Mount Pinatubo in the Philippines shot about 10 million metric tons of sulfur in the air. The eruption managed to reduce global temperatures of about 1 degree Farenheit for a year after.

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