Volcanic Climate Effects

Volcanoes have repeatedly altered global climate. The 1991 Pinatubo eruption sent about 20 million tons of sulfur dioxide into the stratosphere, cooling Earth by roughly 0.5 degrees for two years.

The massive volcanism that formed the Siberian Traps 252 million years ago likely triggered the worst mass extinction ever, wiping out over 90% of marine species. Yet without volcanic CO2 over geological time, Earth would freeze into a permanent snowball — volcanoes are both destroyers and sustainers of life.