Friday, September 9, 2022

Thinking about cities: Were ancient cities greener than modern ones?


*This is part of a series called ‘Thinking About Cities’ which are parts of a book I am working on about urban green space that I’ve decided to cut out of the book manuscript.


Picture a large modern city. Undoubtedly, your mental image includes a lot of grey. Grey buildings. Grey roads. Maybe grey skies saturated with ozone and particulate matter. Yet we don’t see green as a dominant feature of a city despite the undeniable importance of vegetation and green space to the well-being of a city. 


Now picture an ancient city. This image probably has a lot less grey and more browns and greens. We likely see dirt (unpaved) roads, wooden structures, trees here and there, a river with a natural bank, and chickens and other livestock intermingled with human activity. 


Were ancient cities inherently greener than modern cities? If so, was this done by design, or by accident, or because humans lacked the technology to completely transform the landscape? Before we delve into this question, we need to think about what a city is and where it comes from.


History of the city

Cities have evolved from small permanent settlements to massive human-created landscapes that house large and densely packed populations. As Gordon Childe argued (Childe 1950), the city is a revolution. They represent revolutions of technology, governance, economics, and our relationship with nature and place. Nothing like cities existed in all of human history until about 9-10 thousand years ago when the first known large settlements appeared near the shores of the Mediterranean Sea ( These were Jericho in what is today the West Bank and Catal Huyuk in Turkey. These cities housed somewhere between 2 and 6 thousand people).  To understand the origins of the city, we need to look to the birth of the major civilizations, and to find these, we need to go to the banks of the major rivers of the Middle East and Asia. The Nile, Ganges, Tigris, Euphrates, Indus, Yangtze, and Yellow rivers were the cradles fostering the birth of cities. Just like a germinating seed, cities required water to grow. The rivers were the lifeblood of these new forms of civilization and was essential for the irrigated agriculture that fed populations, a supply of drinking water and for construction, a means for moving waste away from human populations, and were the express highways of the day –moving people and goods.


These first major cities were home to several thousand people (certainly less than ten thousand) living in loosely organized communal areas, and though these do not seem like cities by today’s criteria, they were massive by the standards of the day. Pre-agrarian societies supported population densities of about 0.04 people per square kilometre and early agrarian societies, which gave rise to the first permanent settlements, had between 1 and 5 people per square kilometre. Cities today have densities of hundreds or thousands of people per square kilometre.


The shift from nomadic cultures to agricultural ones was the necessary development for cities to emerge. Having a permanent source of food drastically changed how people spend their time and allowed them to produce more food than they could personally eat. Sounds trivial, but this new reality allowed for specialized occupations that were not focused on finding and gathering food. The farmer produces the food, while others pursue their own vocational callings like carpenter, artisan, priest, and so on. With new occupations involving training and expertise, innovation and technological development ensued. Metal workers tested new methods and alloys, farmers found ways to increase yield, and the priests and elites organized people and resources.


By this point, cities were all but inevitable. As different cultures shared information and technology, small cities began to emerge along the great rivers of the world. These rivers all supported the eventual growth of large cities of ten thousand or more people by about 5 thousand years ago. But the rivers also needed to be controlled. While they were an invaluable resource, they could also be unpredictable and devastating. The ancient city of Petra in modern Jordan, was a thriving capital city between 300 BC and 300 AD, but it was subject to floods after heavy storms and the Petroneans built damns and culverts to reduce flooding. This was not unique to Petra. Many ancient city archaeological sites include evidence of engineered structures designed to control flooding.


Cities also required governance. Ten thousand people living together would be chaotic if there wasn’t some sort of government in place to create and enforce rules. For these early cities, this governance was intertwined with religion. Temples were the centre of these early cities and provided guidance, worship, laws, education and were the focal points for political power. People no longer relied solely on family or clan allegiance but were increasingly tied to loyalties to king, high priest, and nation-state. These power structures were important for organizing people and pooling efforts and creativity into larger and larger projects, while promising protection from other nation-states, which were also increasing in power.


The emergence of cities was a slow evolution from small permanent settlements to large centrally governed and densely populated ones. It is hard for scholars to say with certainty when the first city appeared because both the evidence has been washed away by time and it is not entirely clear what a city is.


For ancient settlements, we can say that the designation as a ‘city’ corresponds to certain features that are necessary to successfully house thousands of people in a small area. These would include: sturdy streets capable of sustaining constant use, dense and organized housing, central governance and control of law enforcement, taxation to pay for services and common good building projects (e.g., aqueducts, city walls, etc.), specialized occupations and trades that provide expertise in various elements of culture, governance and construction of cities (e.g., engineers, teachers, etc.), markets allowing specialized occupations to trade goods and services, because blacksmiths do not grow much food and farmers make few metal objects, and finally cities have large and permanent impacts on local environments.


Let us paint a picture of an early city by looking at the largest city in the world during the 11th century –Kaifeng, China (historically called Daliang or Bianjing). Kaifeng was the capital of the Song dynasty (960 - 1279) and at the height of its glory, it was home to somewhere between six hundred thousand and one million people. We actually know a lot about Kaifeng. China is the oldest continuous civilization on Earth and has tremendous collections of historical documents. Further, Kaifeng is still a major city today with a population of about five million people –a medium-sized city by Chinese standards, but a very large one by standards elsewhere. Most importantly, one of China’s most cherished historical artifacts is a giant scroll measuring 5.25 meters (or over 17 feet) long called “Alongthe River During the Qingming Festival”, and it beautifully depicts Kaifeng life during a national holiday. 


A small segment of the painting “Along the River During the Qingming Festival, painted by Zhang Zeduan (1085-1145). It depicts city life in Kaifeng, China at the height of its prestige when it was the capital city and the largest city in the world.

From this beautiful illustration, you can see the elements of what it means to be a city. First, there are lots of people milling around and participating in different activities. There is trade, we see people moving goods in carts and on camels. There are specialized occupations, notice the tea houses and restaurants. There is organised building construction lining a major road. We see the overwhelming evidence of codified economics as people are buying goods and exchanging money (and gambling!). And with economics we see class inequalities as the lady pulls aside the silk curtains and looks out of the litter, or shoulder carriage, being carried by porters. There is a city gate protecting the population and regulating and taxing the flow of goods. If we move along the scroll, we would see the Yellow River and the docks and ships necessary to move people and goods over great distances. Looking at the amazingly detailed depictions in the scroll, we can almost smell the odours and aromas and hear the sounds that permeate through a dense city. Horses neighing, dogs barking, people shouting, and dishes clanging. This was a city by any definition.


So was Kaifeng greener than modern Beijing?

Obviously, Kaifeng, if it existed today, would be a greener city than Beijing. Modern Beijing, or any other megalopolis, is defined by a massive concentration of material and energy that results in a concrete landscape capable of housing millions of people. Keifeng simply had less impervious surface and more space for nature. So, the short answer is yes, ancient cities were physically greener.


But if we think of ‘green’ as being a philosophy or approach that directs how we interact with nature, then I don’t think we can say that ancient cities were greener. Humans have created cities precisely to alter local environments to better suit our needs. A city is the embodiment of our innate desire to increase our own fitness by removing threats (from predators and other people), creating security through strength in numbers, and reducing environment unpredictability. We might want to romanticize early human relationships with nature, but the reality is that once technologies were created that advance urbanization, they were implemented and spread rapidly. Being susceptible to flooding, early cities channelized rivers once they were able to. In response to threats from other groups of people, cities around the world accepted being encased in walls as the technologies emerged.


The history of cities can be seen as a continuum from small and low-impact settlements to large, urbanized landscapes like Tokyo. What drives a smaller and greener city towards being a megalopolis? So long as the population demand is there and the technologies to build a city exist, the megalopolis is all but inevitable.


Unlike previous generations, we are in a unique position to ask the question, what do we want a city to look like? Most of the technological hurdles that would limit urbanization have been overcome. We now have the conceivable ability to create a completely urbanized planet, like Coruscant from Star Wars. But most people would think that this is a bad idea. But is barely constrained sprawl around urban centres like Los Angeles, Mexico City, Delhi, and Toronto not a microcosm for these urbanizing forces that we think are ultimately undesirable?


The point is that neither in ancient times nor now do people have an agreed upon vision of urbanization’s endpoint. Urbanization has been and is driven by the mix of demand and technology, but we now need, more than ever, an agreed upon vision and set of principles directing urbanization. We need cities that minimize environmental impact, reduce the effects of inequality, and ensure people realize the potential benefits of green space.


So, were ancient cities greener than cites today. Yes and no. While they had less impact on their local environments, the megalopolises of today were written into their DNA. The devaluation of nature has always been a defining feature of cities. Now, more than ever, we need to rethink the relationship between the city and nature, and rewrite what is coded in a city’s DNA.


Childe,V. G. (1950). The urban revolution. Town Planning Review, vol. 21, pg. 3-17.

No comments: