Bad things come in threes, it is said, and nothing shows that more than The Carnian Age; the first stage of three in the mass extinction era of the Late Triassic Epoch 228 to 217 million years ago.
It had three features; dramatic climate change with much higher humidity, the first dinosaurs appeared, and gigantic volcanic eruptions called the Wrangellia large igneous province spewed out greenhouse gases.
For dinosaurs, climate change was a good thing because plant life grew, thanks to the humid conditions and higher carbon dioxide. That event, now called the Carnian Pluvial Episode, may have been caused by the Wrangellia volcanic eruptions. The confluence of events seems to have spurred the early diversification of dinosaurs.