BABYLON, HILLAH, IRAQ - NOVEMBER 20, 2016:  This is DigitalGlobe closeup satellite imagery of the remains and location of Babylon -- and ancient city in Mesopotamia.  Located in Hillah, Iraq. (Photo DigitalGlobe via Getty Images)

Earth’s ancient geography ‘directed the course of human evolution’

In his new book, Origins, astrobiologist Lewis Dartnell shows us how the Earth’s ancient geography has influenced the development of human civilisations, and how it still affects our behaviour today.

What is Origins about?

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It’s about the many ways that different features of planet Earth have directed the course of human evolution and influenced the growth and development of civilisations over thousands of years. It looks at fundamental features like plate tectonics, or atmospheric circulation patterns, showing how they’ve directed the course of our history and why the world is the way we find it today.

What prompted you to write the book?

I’m an astrobiologist, which is all about looking at the possibility of life on other planets, so I spend a lot of my day-to-day working life thinking about how the features of Earth have made it habitable in the most fundamental sense. I wanted this new book to expand on that – to bridge the gap between science and history and see how they inform each other. Through Origins I try to weave those two back and forth through the chapters of the book, like two strands of a narrative.


Listen to the full interview with Lewis Dartnell in the Science Focus Podcast


You talk about plate tectonics in the book. How have they affected human development?

When you look at a map of where ancient civilisations started, a lot seem to huddle along tectonic boundaries. Plate boundaries are dangerous places to be in one sense, because that’s where earthquakes and volcanoes are concentrated, but clearly they’re also providing some sort of benefit.

Take Mesopotamia, the land between the Tigris and the Euphrates rivers in the Middle East. That entire region is essentially running along the tectonic trough that was created when the Arabian plate pivoted away from Africa and slammed into Eurasia, which then collected great rivers and sediment to make fertile soil.

So in that particular instance there’s a very clear reason why some of the earliest cities in our history grew up around that particular tectonic region, as it was a really conducive place to settle down and go through the beginnings of agriculture.

How has geography influenced current behaviour?

One modern example is the election of Donald Trump. If you look at an election map of the southeast region of the US, it’s a sea of Republican red. But in that sea of red there’s this very distinct crescent shape of blue, of people voting Democrat. If you look at a geological map, underneath that crescent of Democrat-voting counties is a stratum of thick, fertile sea mud that dates back 60-70 million years.

Cotton grew well in that rich fertile soil, and in the 1840s, 1850s and 1860s, slaves were used to grow and harvest cotton. More than 150 years later, the descendants of those slaves still live in that region, and their socioeconomic background means they’re more likely to be voting Democrat, rather than Republican.

Is it important to be aware of how these physical formations are influencing our behaviour?

We’re now turning all of this on its head with our modern industrialised civilisation. A lot of scientists are calling this current era the Anthropocene, because humanity has become the dominant force in changing our planet.

We’ve got a lot of problems on our doorstep to do with climate change, global warming and ocean acidification, and we need to find solutions to them so we can keep living the way we’ve become accustomed to.

I think by appreciating this deep link behind how the Earth has made us and how we’re now affecting the Earth in return, you just appreciate everything around you a little bit more, and understand why we need to take extra care of the planet.

Origins: How the Earth Made Us by Lewis Dartnell is out now (£18.99, Bodley Head)

Origins: How the Earth Made Us by Lewis Dartnell is out now (£18.99, Bodley Head)

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