Why Modern Earth Is Different — Pleistocene to PETM

This week, award-winning science writer Peter Brannen returns to Decouple to explore the 4.5 billion-year story of carbon dioxide on Earth. Grounding our discussion is his new book, The Story of CO2 Is The Story of Everything. From the alien world of the Hadean eon to humanity's emergence as the "pyromaniac ape," Brannen reveals how this trace gas has shaped every aspect of our planet's evolution, through Snowball Earth, mass extinctions, and the rise of complex life, culminating in humanity's unprecedented ability to burn fossil fuels.

We talk about:

• The origin of life and early carbon chemistry

• Why Earth needed fossil fuels to create an oxygen-rich atmosphere

• The Great Unconformity and Snowball Earth's role in building the rock record

• The Carboniferous period as the age of giant insects and coal formation

• The Permian mass extinction and Siberian Traps volcanism

• The Paleocene-Eocene Thermal Maximum as a climate analog

• The ice age world that shaped human evolution and the rise of agriculture

• How megafauna extinctions marked the beginning of human planetary impact