UCL Earth Sciences


Born of Ice and Fire

17 October 2023

This book, written by Prof Graham Shields explores how the Cryogenian Period, when our planet was covered in ice for millions of years, created today’s remarkable biodiversity.

Book title: Born of Ice and Fire

Ever since Darwin, one of the most vexing problems in science has been the apparent absence of any long fuse to the Cambrian explosion of animals about half-a-billion years ago. Recently, it has become apparent that the long Cryogenian Period, a time of unimaginable cold, holds some of the clues. This first-hand account of the Snowball Earth controversy is based on more than three decades of fieldwork around the world.

The book sketches out how and when conditions enabled animals to evolve into our earliest ancestors, and narrates a journey that navigated incredible extremes. In providing a holistic view of the Earth as a complex, emergent system, the book seeks to answer questions such as: What causes extreme climate change and could global glaciation ever happen again? How did life not only survive Snowball Earth but spawn our direct ancestors in its aftermath? And what can this tell us about the likelihood of complex life elsewhere in the universe? 

a huge boulder, locally called the BubbleCaption: 717 million years ago, the world entered the Cryogenian Period of global glaciation. The photo shows a huge boulder, locally called the Bubble, that was scraped off the underlying limestone reef and folded back on itself by the immense forces of the overlying ice sheet (Eileach An Naoimh Island, SW Scotland). Fred Bowyer (Edinburgh Uni. PDRA and Elias Rugen (UCL PhD student) for scale.

Early reviewer comments:

“A spellbinding read from one of the deepest thinkers about deep time. Part scientific autobiography, part paean to unsung heroes of the past, and part thrilling detective story, this book is the culmination of three decades of field research. Graham Shields pieces together an astonishing new answer to the oldest question: Where did we come from?”—Nick Lane, author of Vital Question: Energy, Evolution, and the Origins of Complex Life

Born of Ice and Fire is a fresh take on the mystery that most vexed Darwin: the seemingly sudden appearance of animal life in Cambrian strata. Graham Shields explores Earth’s evolving biogeochemical system and the extreme ice age that ushered in a brave new oxygen-rich world.”—Marcia Bjornerud, author of Timefulness: How Thinking Like a Geologist Can Help Save the World