What do geologists believe the earth was like 250 million years ago?

In the Late Permian, a volcanic region in India called the Deccan Traps formed, pumping large amounts of gases into Earth's atmosphere. These created a greenhouse effect, raising global temperatures. This is known as the End Permian Extinction.

By the Permian-Triassic boundary, 250 million years ago, vast deserts covered the planet. Over 90 percent of all animal species on Earth had died out.