Fifth extinction event

The Cretaceous and Paleogene extinction occurred 66 million years ago.

A 90°C heat wave engulfed the world, followed by a rapid cooling that caused this extinction.

Value	Unit
Temperature change
∆ ~5.2	°C
Rate of temperature change
10 to 100	°C per million year

The impact of an asteroid in Yucatán, Mexico caused this extinction. Some changes may have occurred before this asteroid, with intense volcanic activity and tectonic lifting. Sunlight was blocked for a few months.

Extinction rates:

76% species
40% genera
17% families

Before this extinction, dinosaurs experienced a large increase in diversity and abundance and became the dominant vertebrates in terrestrial ecosystems. Mammals also diversified greatly but remained small.