Mass extinctions are rapid global decreases in Earth’s biodiversity, with five key events identified over the planet’s history, arguably the most famous of which occurred ~66 million years ago during the Cretaceous, which brought the rein of dinosaurs to an end. However, the largest mass extinction is attributed to the Permian, during which it is estimated that >95% of all life on Earth was eradicated.

The cause of this devasting event is still debated, with advocates for both a large asteroid impact that caused dust to plume into the atmosphere, blocking sunlight and generating acid rain, or significant volcanism that released copious amounts of CO2 into the atmosphere and made the oceans toxic to marine life.

New research published in Chemical Geology lends further support to the latter theory.