Volcanoes Led to Earth’s Biggest Ice Age, Latest Research Suggests

This is how the Earth may have appeared about 650 million years ago during a period when snow and ice may have covered most, if not all, of the Earth's surface and oceans. This image suggests the Earth's appearance during the Marinoan glaciation from 650 to 630 million years ago. The southern and eastern hemispheres are dominated by glacier-covered land masses while the opposing hemisphere is frozen ocean save for a few areas of exposed liquid water, AKA refugia for the Earth's surviving soft-bodied multicellular organisms. In addition to the Marinoan glaciation there may have been at least two, and possibly three previous Proterozoic glacial periods going back to two billion years ago. The causes of these snowball periods are unknown but may have been due to massive volcanic eruptions, massive meteoritic impacts (both resulting in global sun-reflecting ash clouds), or variance's in the Earth's orbit.
(Getty Images)

 

A new theory behind the Earth largest Ice Age, a period dubbed “snowball Earth,” points to volcanoes as the culprit—with a chain of eruptions occurring at the right time and places for the most impact possible.

About 717 million years ago, glaciers covered the entire surface of the planet in ice. Scientists have long debated the root causes of this glacial event, according to Phys.org.

Harvard University researchers now reason the extreme global phenomenon was caused by a period of intense volcanic eruptions—spanning 2,000 miles wide and lasting about a decade—that began just as the planet started to cool.

In their study published in Geophysical Research Lettersthe scientists say a cooler climate made it more susceptible to the sunlight-blocking effects of sulfur dioxide spewing from the volcanoes. The volcanic ash hit the stratosphere around the equator where the most radiation enters to keep the planet warm.

As a result, more ice began to form than previously, which in turn reflected more sunlight, cooling the planet down further in a cycle that continued until it reached its apogee.

The new research could shed light on extinctions events and better inform our understanding of how climate change occurs on other planets, too.

—RealClearLife


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