The overall theme of this set of four challenges is "Every Day is Earth Day: 365 Books to Start Your Climate Change Library"
"we finish ... with The Ideas, the philosophies, psychologies, politics, and pathologies arising from our proximity to environmental collapse." (Lit Hub, 2019)
This is the 4th and last part of a 4 part series. The parts are as follows:
Part 1: The Classics
Part 2: The Science
Part 3: Fiction and Poetry
Part 4: The Ideas