Right around 3700BCE, the Sumerians founded a city called Eridu. With a population of around 6000, it was the first real urban area, and undoubtedly the largest collection of humans in one spot up to that time. If you buy the Toba Bottleneck Theory (which most don’t, but there is evidence of some bottlenecking in the Pleistocene) some 50,000 years before that there were only maybe 10,000 humans total. That is an endless amount of time in the scale of our lifetimes, but it was incredibly rapid. During Toba- or at least that time, no matter what your mileage on the bottleneck- humans had very little impact on the planet. Post-ice age hunting certainly had an effect, particularly in North America. But we hadn’t yet taken over the planet. Urbanization was one of the twin engines that drove the Anthropocene, the other being widespread agriculture.
It’s also the great story of our time. From that weird beginning, in a place that must have seemed like a crushing enormity, but now would be a two-stoplight drive through, urbanization very slowly took over the world. Over the next 4000 years it was largely limited to a narrow latitudinal band, and even by the time the New World was being colonized, and north and south took on new meaning, most of the world was rural. It was only in the last 50 years that mass urbanization started taking place.
This is now beautifully visualized thanks to a landmark study on cities by Meredith Reba, Femke Reitsma, and Karen C. Seto. In it, using several data sets, they have compiled the most thorough history of urbanization that I’ve seen. They aren’t as concerned with strict definitions, but more what constitutes a large city at any given time. Cahokia, the largest city north of Mexico before colonization, makes it, whereas nearby current East St. Louis, with a larger population than Cahokia, does not. I think this is fair.
Just as exciting, at least in a visual stimulation sort of way, is the ability to map it out and watch it. I took a screenshot from Metrocosm, which is an invaluable site. In it, Max Galka shows cities popping up. It’s amazing to watch the pace, as they first center in modern-day Iraq, spread slightly east and west, and start to really roll as India and China develop their eternal cultures. Then Europe and Mesoamerica, then elsewhere, more north and more south, but still spaced out. Then the 20th-century these urban area start to spring up everywhere, and in the last few seconds of the video, it’s a violent epileptic explosion of dots, each one representing the lives of hundreds of thousands and of millions. It’s amazing. (The Guardian has a video as well, shorter and set to a jauntier tune.)
What we see with these maps, and in these datasets, is a dramatic visualization of the choices we have made as a species. I personally am very much in favor of urbanization, and think that it is a great way to reduce our impact on the planet, if done correctly. But there isn’t a way to mistake it: by transforming the land for agriculture, and then transforming the very basics of water drainage, light, sound, and other factors for urbanization, we’ve created the most species-driven environmental change since (arguably) the Great Oxygenation Event, which most scientists will tell you was a bad scene, man. Remember that the great cities of Mesopotamia were not dry and dusty, but lush and verdant.
But not to be a pessimist entirely. The data and the videos are also thrilling. It’s a stirring wonder, that atavistic gnaw in your stomach, to imagine a citizen of Eridu, gazing in wonder at the crowds. Did they know what they had accomplished? Did they know that a mere generation or two before such a thing was unimaginable? Surely they did; they had the imagination to build. They had the imagination to plan for a future. They had the knowledge to remember the past. They were us.