Acid rain led to mass extinction 250 mn yrs ago

A new study, published in the journal 'Geology', shows that acid rain and ozone depletion caused the extinction of over 90% marine species and 70% terrestrial species 250 million years ago. Gases released during contemporaneous volcanic eruptions in Siberia resulted in ecology-damaging pH fluctuations and UV radiations. These combined with global warming led to the earth's worst known species die-off.