Book Reviewed: The Worst of Times: How Life on Earth Survived Eighty Million Years of Extinctions, by Paul B. Wignall

Life on collision course with forces of nature

About 251 million years ago, life on planet earth was almost extinct. Most species were lost in a catastrophic event along with the loss of habitats for of most land and marine creatures. It took almost 100 million years for life to return to pre-existing level, and the biodiversity returned in the form of diverse marine creatures, insects, dinosaurs, mammals and plants. In this process, animals and plants took various shapes, sizes and habitats. In this book, University of Leeds professor, Paul Wignall examines the environment of Pangea when the planet was fused into one single super continent. Atmospheric and geological conditions were vastly different with few coastline habitats, limited rainfall, and the deeper part of the land uninhabitable. Huge volcanic eruptions resulted in catastrophic events that filled the atmosphere with carbon dioxide and covered the land with lava. Changes in atmospheric temperatures, acidification of the ocean and depletion of life-supporting oxygen made the planet very hostile for life. Eventually a slow and steady separation of the single land mass into five continents changed the planet’s atmosphere and created diverse environment. Species evolved in the reformed planet with a tremendous increase in diversity.

Recent studies have suggested that the asteroid that hit Yucatan Peninsula 65 million years ago also intensified volcanic eruptions in the Deccan Plateau of India. Volcanic eruptions became twice as intense, throwing out a deadly cocktail of sulfur dioxide and carbon dioxide. The shockwaves produced at this time shook up earth and its volcanic “plumbing systems” around the world, creating larger magma chambers that spewed out more material. This “combined effect” is now believed to be responsible for wiping out dinosaurs.

Sir Charles Lyell was the first geologist to propose, in the first half of the nineteenth century, that earth was formed after cataclysmic events on giant scale in the distant past. He observed that the earth was shaped by slow-moving forces still in operation today, but acting over for a very long period of time. This idea still holds good and it was quite bold for his time when it was believed in the idea of abrupt planetary changes that conforms to beliefs of the Book of Genesis.

While geological and paleontological studies have been helpful to understand the formation of a habitable planet such as earth, we are still a long way to account for all factors that shaped our world. This is especially critical when NASA is investigating life on exoplanets with vigor and enthusiasm. Professor Wignall’s seminal work in this area is fascinating and should encourage readers to get interested in this field and learn more about the ancient history of our planet.