Several hundred million years ago the Earth was almost completely covered with snow.
American geophysicists have called the reason why a few hundred million years ago the Earth was almost completely covered with snow. A study published in the journal Geophysical Research Letters.
According to scientists, the reason that 717 million years ago, for about one hundred thousand years a large part covered with ice, was volcanic activity on the spot Franciscoi igneous province located on the territory of modern Alaska and Canada.
The eruption resulted in the release of the tropopause (the layer of the gas envelope between the troposphere and the stratosphere located at a height of 6-20 kilometers), sulfur dioxide and hydrogen sulfide. These compounds led to the formation in the stratosphere sulphate aerosols — droplets that reflect sunlight and thus reduce heating of underlying layers of the atmosphere and the surface of the planet. During the volcanic activity that, according to the authors, has led to a decrease in tropopause height.
Scientists noticed that the eruption of mount Pinatubo on the Philippine island of Luzon, which occurred in 1991, led to the emission of ten million tonnes of sulphur during the year have reduced global temperature by about 0.5 degrees Celsius. The authors also noted the presence of feedback loops — increased volcanic activity in ancient times, when glaciers extended up to the territory of modern California, led to a more intense reflection of sunlight by ice and consequent more rapid cooling of the planet.
Previously, scientists had known that the formation of Franciscoi igneous province and the first global glaciation of the Neoproterozoic era occurred approximately at the same time. The study found a possible causal relationship between phenomena.
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