The earth made us

Those are the last four words of “Origins,” by Lewis Dartnell. I recently read Darwin’s “Origin of Species,” and before that “Guns, Germs and Steel,” Jared Diamond’s excellent account of how human societies succeeded or failed based on the accidents of plant, animal and climate distributions. “Origins” is the story of life on earth told from the point of view of geology, plate tectonics and global climate. I was aware that the cradle of our species lay in the rift valley of Eastern Africa, but I didn’t connect “rift” with the movements of tectonic plates, let alone how that particular geology brought together just the right climate conditions at just the right time to drive our ancestors out of the forest and into the grassy plains. Similarly, I knew about the recent ice age and the peopling of the Americas by travel across the Bering land bridge, but I didn’t realize that horses and camels originated in the Americas and traveled the opposite direction into Eurasia before going extinct in the land of their origin.

The impact of coal and oil on our present-day world economies (and the disastrous global warming now resulting) is a familiar story, but Dartnell tells us the peculiar geological, ecological and climatological circumstances of their formation in the Carboniferous (coal) and late Jurassic/Cretaceous (oil and gas) eras. Indeed, many of the finer details of human history are plausibly explained by accidents of our planetary geology. The distributions of important metals—copper, iron, silver—that drove men to great feats of exploration and cruel acts of violence owe themselves significantly to plate tectonics.

The conquest of the world’s oceans by sail is the story of wind circulation patterns and ocean currents. The monsoons of South Asia not only affect the annual wet/dry cycle on land but drive a unique air circulation pattern in the Indian Ocean that drove the history of European colonialism.

I was surprised at how much I didn’t know about world history by reading this book. I guess I’d always thought of geology as separate from human history, except as it affected migration patterns and agriculture. I learned a great deal from this book, and the writing made that education pleasurable. I highly recommend this book.