Can an ancient volcano destroy the Earth?

According to some researchers, after the eruption of the volcano Toba, the Earth suffered a drop in temperatures around 10 ° C. From Rutgers University in New Jersey, there are new studies that seem to discredit these theories.

About 74,000 years ago, a volcano in the Sumatra Island, the gigantic Toba began to emit steam from the top, signs of strong ongoing activities. It erupted with the emission of rocks and other materials a thousand times greater than those erupted in 1980 from Mount St. Helens in Washington State.

Previous studies argue that, following the eruption, a long process of the Earth's climate cooling started, decreasing the temperature about 10 ° C. The main cause is thought to be due to greenhouse gases emitted by the volcano, together with carbon dioxide and sulphur. The latter, when combined with water vapour, spread sulphate on the terrestrial globe in the form of aerosols, delaying the journey to Earth of the solar radiation and cooling the air until the formation of acid rain and snow.

It was the start of an ice age that lasted about 1000 years and that may have led to a "volcanic winter", causing famine and a drastic reduction of the population over time. Some geneticists believe that it has had a catastrophic effect on human life, reducing Earth’s population to just a few thousand people.

But the models developed by NASA and the National Center for Atmospheric Research in Boulder, Colorado, does not endorse these theories, because the climate simulations have not reproduced the hypothesized glaciation.

Alan Robock of Rutgers University has conducted some simulations based on advanced models that include the effects of the death of vegetation due to the radiation and chemical reactions that simulate the condition of the volcanic origin cloud. The purpose of the study was to investigate additional mechanisms that could have improved and/or have extended the effects of the eruption of Toba.

The Robock’s team simulated injections of aerosols (obtained by sulphur dioxide) in the processes, ranging from 33 to 900 times the quantities found for the eruption of Mount Pinatubo in 1991, but no  glaciation was obtained from these simulations. The results, published in the Journal of Geophysical Research Atmospheres, speak only of cooler climate for several decades. It was assumed therefore that the cold spell that lasted for 1000 years, follows a natural cycle, like the other dozen ice ages of the past.

Climatologist Ellen Mosley-Thompson of Ohio State University in Columbus says that according to this research, volcanic eruptions are excluded from being mentioned as one of the main causes of glaciation of the Earth. For this reason, the scientists should concentrate their studies more on changes in ocean circulation or cyclical variations on the Earth's orbit around the Sun

And if Toba erupted today as it did in the past? It would be a disaster.

Robock and his colleagues estimated that a big eruption would lower global temperatures about 17 ° C for several years, followed by decades to return to normal conditions. This could affect the human population reducing agricultural production and vegetation, causing lack of food, famine and death.

Two years after the Tsunami, the Toba volcano resumed its activity with harmonic tremor. Some scientists say it will again be a candidate to become a super volcano in 2012.

According with the results of these studies, let’s hope that this does not happen.