Why Geology Matters: decoding the past, anticipating the future by Doug MacDougall. University of California Press, Berkeley, 2011. No. of pages: xiv + 285. Price: US$24.95. ISBN 978-0-520-27271-2 (paperback).


This book is full of surprises, all good. The title was a surprise and it made me assume, erroneously, that this volume is a superficial text that hopped around the Earth sciences like a kangaroo in heat. Then, the book itself was a surprise. It does make some big leaps in direction between chapters, but each holds together well and is packed with meat, while the changes in direction are expertly handled so that transitions are smooth. This second surprise was very welcome; indeed, Why Geology Matters is one of the most informative new books on the subject that I've read for some time—and I read it avidly. I must emphasise that MacDougall is a fine writer and his style of writing is highly readable.

Why Geology Matters is a real beauty of a book on general geology for any reader, whether professional, amateur or student. Why Geology Matters is broad, informative and well written; it is as close to being a compulsive book to read as any that I've seen in semi-popular science. MacDougall's message is of the utmost seriousness, that the Earth has survived many major environmental perturbations from diverse sources since it formed and that our detailed knowledge of the range of these events can be a key to future concerns, such as climate change, that just won't go away without informed action. The truly pleasing aspect of this book for me was the amount of up-to-date information and interpretation that it contains; I was surprised and delighted to find much of it new to me.

How does MacDougall reveal the Earth? He alternates between chapters explaining parts of the Earth's history, such as Chapter 7, ‘Mountains, life, and the big chill’ (=the Proterozoic), and the explanation of major environmental perturbations in the past. Some of the latter are exotic—bolide impacts, eruptions of supervolcanoes—while others are being repeated at the present day—climate change, mass extinction. I congratulate MacDougall for the pains he has taken to demonstrate how solid scientific methodologies have provided near-incontestable explanations of ancient catastrophes, and how these data and interpretations are being extrapolated to explain what is happening today and tomorrow. Certainly, the future doesn't look rosy.

Why Geology Matters is not top heavy with jargon, although it may have benefitted from an explanatory glossary. More importantly, it is not encumbered with marginally relevant illustrations. Rather, the figures (mainly line drawings) support the text to perfection. They have obviously been carefully chosen and play their role as cornerstones for MacDougall's story. My favourite (fig. 29) is a line of four computer-generated spheres of increasing size. It provides ‘A comparison of estimated eruption volumes for the volcanoes discussed in this chapter’ (caption), namely Pinatubo in 1991 (small sphere equivalent to 11 km2), Yellowstone 640 000 years ago (much bigger), Mount Toba 74 000 years ago (bigger still) and La Garita (28 million years ago and almost unimaginably huge, equivalent to about 5000 km2). It is this sort of illustration that engages the reader and demonstrates what the numbers really mean.

Why Geology Matters is an outstanding achievement, highly readable, informative and deserving to be widely read. I commend it to everyone with an interest in the Earth sciences; it would certainly be a thought-provoking text for an undergraduate class. But, most importantly, it is a book that will bring many of us up-to-date on so many important issues related to the health of this planet.