Their choices for non-fiction:
Silent Spring by Rachel CarsonRead about the fiction on the list.
Development as Freedom by Amartya Sen
Soil Not Oil by Vandana Sheeva
The Revenge of Gaia by James Lovelock
The Selected Works of Arne Naess
So Shall We Reap by Colin Tudge
Feeding People is Easy by Colin Tudge
Collapse by Jared Diamond
Six Degrees by Mark Lynas
Heat by George Monbiot
Collapse appears on Andrew Ellson's critic's chart of books on "cash crashes."
Also see--Ten of the best: green stories in literature.