What triggers a mass extinction? Habitat loss and tropical cooling were once to blame

What triggers a mass extinction? Habitat loss and tropical cooling were once to blame: The second-largest mass extinction in Earth's history coincided with a short but intense ice age. Although it has long been agreed that the so-called Late Ordovician mass extinction was related to climate change, exactly how the change produced the extinction has not been known. Now, scientists have determined that the majority of extinctions were caused by habitat loss due to falling sea levels and cooling of the tropical oceans.