When a history book leaves you reeling, you know that it has done its job properly. Climate Change and the Health of Nations is a grand synthesis of environmental history, charting the fate of civilizations and the links between climatic changes and the health of people. It is also a book that almost wasn’t.
What has plate tectonics ever done for us? Not having studied geology, I have a basic understanding of the movement of earth’s continents, but this book made me appreciate just how much of current geology it underpins. Marine geophysicist Roy Livermore, who retired from the British Antarctic Survey in 2006 after a 20-year career, convincingly shows here that the discovery and acceptance of plate tectonics was a turning point in geology, on par with Darwin’s formulation of evolution by natural selection. To paraphrase evolutionary biologist Theodosius Dobzhansky: nothing in geology makes sense except in the light of plate tectonics.
Before plate tectonics became an accepted idea in geology, Lyell’s doctrine of uniformitarianism still ruled supreme (see my review of Cataclysms: A New Geology for the Twenty-First Century for a short introduction). A corollary was that the continents supposedly had always been where they are now. One observation scholars had to explain away was that the same fossils occur on both sides of the various oceans. Looking at maps, some people noticed the thin strip of land connecting North and South America and concluded that land bridges must have formed and sunk beneath the waves at just the right times in history to enable migrations (see Four Revolutions in the Earth Sciences: From Heresy to Truth for more details). As explained in The Tectonic Plates are Moving!, we know better nowadays. Nevertheless, the concept of land bridges is still alive and well today, and palaeobotanist Alan Graham here introduces five of them, exploring their effects on biogeography, climate, and human history.
This book is an example of what happens when you go down rabbit holes. I have been reading several books on the subject of palaeontology and geology lately, and I know that the face of the earth has shifted over the hundreds of millions of years of deep history covered in these books. But where were all the continents at different times? Many will have seen the iconic maps of the supercontinent Pangaea. But I want to know more. What happened in between? And before? As Nield tells in Supercontinent: 10 Billion Years in the Life of Our Planet, Pangaea was only one of several such supercontinents in Earth’s history. But I want to know more still. Where exactly were the continents located? And how did they move? Several accessible books have provided snapshots of iconic moments, such as the formation of the Himalayas (Mike Searle’s Colliding Continents: A Geological Exploration of the Himalaya, Karakoram, & Tibet) or the disappearance of the Tethys ocean (Dorrik Stow’s Vanished Ocean: How Tethys Reshaped the World). But I want to know more! This technical reference work contains lots of fantastic palaeogeographical maps that answered all my questions.
So, stop me if you’ve heard this one before, but it is often said that we know more about the moon than we do about our own oceans. However, palaeo-oceanographer and climate scientist Eelco J. Rohling points out we know more than you might think. His new book, The Oceans: A Deep History, takes the reader through a 4.4-billion-year history of Earth’s oceans. Much more than just a book about water, this is foremost a book about the intimate link between our planet’s climate and its oceans, as they are far more intertwined than you might give them credit for.