16 May 2021
Andy Knoll wrote a masterful, fascinating book in 2003, Life on a Young Planet. Now, 18 long years later, he’s published another popular science volume, an eight-chapter encapsulation of our planet’s story. I don’t know why he’s waited so long (busy doing science, I guess) but he really does have a talent for telling geobiological stories in a full but accessible way. Knoll is a paleontologist, and the great theme he explores in Earth’s biography is the interaction between the nonliving and living portions of the planet. The volume is organized chronologically, starting with 30 pages on the chemical processes that developed in the condensation of the presolar nebula, then moving into the physical processes that organized the planet into layers and triggered motions in some of those layers, into the origins of life, and the rise of oxygen. Animals and plants get a chapter each, which leaves one for a discussion of singular catastrophes (LIPs, extraterrestrial impacts) that interrupt the flow of evolution, and the human influence of natural systems after that. Knoll draws a parallel between the end-Permian mass extinction and the current “Anthropocene” suite of changes in the planet, concluding that the next chapter in the saga is up to us all, collectively, to write.