Sapient life, descended from gorgonopsians, after a chance wandering in the shrubland of Gondwana that isolated them several million years before, evolves shortly (some 90,000 years) before the Permian Extinction, which wipes out 95% of all life on Earth, like that extinction does in OTL (it is the biggest extinction ever to strike Earth). Civilization arises 11,000 years before the extinction, starting near the mountains in the middle of the Pangaean supercontinent. By the time of the extinction, airplanes fly the skies over the Paleo-Tethys Ocean from and to the lands surrounding it and the larger Panthalassic Ocean is being explored, and there is a high level of technology. Then the Siberian Traps eruptions begin anew, releasing great clouds of methane (thus triggering the extinction)..