The Worst of Times: How Life on Earth Survived Eighty Million Years of Extinctions

Wignall, professor of paleo-environments at the University of Leeds, presents a sound examination of an 80-million-year span, which began nearly 260 million years ago, that is considered by scientists to have been the most extreme extinction event in the Earth’s history. He reveals that research into the event’s causes, which resulted in “the loss of more than 90% of all species” on Earth, points to the impact of volcanism on the supercontinent Pangaea, on a scale that is orders of magnitude beyond what humankind has experienced. He follows the pattern through the end-Permian and end-Triassic mass extinctions and four lesser crises, in each case assessing multiple theories and lines of evidence about the causes of the events. Wignall points to severe warming episodes as factors in these cataclysms, but he avoids drawing too strong a connection between these episodes and climate change today. Wignall critiques hypotheses that don’t support his own concept, but he also freely acknowledges instances when his own case is not fully proven. In sharing this story of the scientific process, he also gives credit to colleagues pursuing related research. Readers will inevitably encounter difficult terminology, but Wignall explains the relevant concepts to laypersons, making for a great example of scientific sleuthing. Illus. [em](Oct.) [/em]