717 million years ago, the planet transformed into Snowball Earth in a perfect flurry of ice and fire.
(Photo : Mario Tama/Getty Images)
Roughly 717 million years ago, the planet turned into a bizarro-Earth ice kingdom known as Snowball Earth. It«s the largest glaciation event in the planet»s history, covering the entire world in ice for about five million years. This has also never been completely explained, puzzling scientists for years.
According to a report from Harvard University, this was also around the time when a huge volcanic event destroyed a region extending from present day Alaska to Greenland.
Harvard University professors Francis Macdonald and Robin Wordsworth believed the simultaneous occurrence of these two catastrophic events may not be a coincidence. After all, volcanic activities are known to have a major impact on the environment, so the researchers sought to answer how the two events could actually be related.
The answer is a perfect storm of all the necessary elements — ice and fire — lining up to produce the precise conditions for the snowball Earth.
The volcanic eruption at the region known as the Franklin large igneous province would have spewed sulfur dioxide in the atmosphere, where it can quite effectively block solar radiation. It«s most effective when it reaches the height of the tropopause, which is the boundary separating the troposphere and stratosphere. Once the sulfur dioxide reaches this point, it»s more likely to be pulled back down and can extend its time in the atmosphere.
However, the height of the tropopause barrier and consequently, the likelihood the sulfur dioxide from the eruption can reach it depends on the climate of the planet at the time. The cooler the planet, the lower the tropopause.
It«s also important to note that 717 million years ago, the Franklin large igneous province was located near the equator, where most of the solar radiation for Earth is pointed at. Furthermore, the eruptions weren»t a single event from just one volcano. Instead, the ones that might have caused snowball Earth was a range of volcanoes spanning nearly 2,000 miles across Canada and Greenland. They also erupt continuously, much like the ones currently spewing in Hawaii and Iceland.
The researchers estimated that around a decade of such eruptions could have produced enough aerosols in the atmosphere to rock the climate situation of the planet.
«Cooling from aerosols doesn’t have to freeze the whole planet; it just has to drive the ice to a critical latitude,» Macdonald explained. «Then the ice does the rest.»
The findings are published in the journal Geophysical Research Letters.