astralavista

The Geological Society of London have told the British Government that catastrophic volcanic eruptions "might threaten global civilzation." It said that such eruption, hundreds times larger than Krakatoa, would cause damage comparable to the impact of a 1 kilometer asteroid, but is 5 to 10 times more likely. "Such eruptions are quite frequent on a 'geological' timescale, although not one has occurred on Earth in the short time that an interdependent human civilisation has existed," the society said. "There may be several super-eruptions large enough to cause a global disaster every 100,000 years. This means super-eruptions are a significant global humanitarian hazard. They occur more frequently than impacts of asteroids and comets of comparable damage potential."
Prof. Steve Sparks of the University of Bristol, co-lead author of the report, said: "Several of the largest volcanic eruptions of the last few hundred years, such as Tambora (1815), Krakatoa (1883) and Pinatubo (1991) have caused major climatic anomalies in the two to three years after the eruption by creating a cloud of sulphuric acid droplets in the upper atmosphere. These droplets reflect and absorb sunlight, and absorb heat from the Earth - warming the upper atmosphere and cooling the lower atmosphere. The global climate system is disturbed, resulting in pronounced, anomalous warming and cooling of different parts of the Earth at different times."
The detailed report is still under embargo. But last month, American scientists reported that huge volcanic eruptions in Siberia some 250 million years ago may have caused mass extinction of plants and animals.