Cities are one of the main ways humans inhabit the landscape and organise themselves, though they have only recently, historically speaking (Data), become where most people live. They, historically, made up for their lack of population with concentration and by being major economic, cultural and political centres. While climate potentially change the locations of our major cities, possibly further inland, I think its more than likely that our current cities will exist during and shortly after overshoot. After all Sydney was founded by convicts with no access to fossil fuels and only indirect assistance from them (in the form of the British Empire). Therefore, if cities will play a role in overshoot the obvious question must be answered.
What is a city?
To aid the answer here is an appropriate extract from Terry Pratchet’s Night watch
Everyday, maybe a hundred cows died for Ankh-Morpork. So did a flock of sheep and a herd of pigs and the gods alone knew how many ducks, chicken and geese. Flour? He’d heard it was eighty tons, and about the same amount of potatoes and maybe twenty tons of herring. He didn’t particularly want to know this kind of thing, but once you started having to sort out the everlasting traffic problems these were the facts that got handed to you.
Everyday forty thousand eggs were laid for the city. every day, hundreds, thousands of carts and boats and barges converged on the city with fish and honey and oysters and olives and eels and lobsters. And to think of the horses dragging this stuff, and the windmills… and the wool coming in, too, everyday, the cloth, the tobacco, the spices, the ore, the timber, the cheese, the coal, the fat, the tallow, the hay EVERY DAMN DAY….
And that was now. Back home, the city was twice as big….
Against the dark screen of night, Vimes had a vision of Ankh-Morpork. It wasn’t a city, it was a process, a weight on the world that distorted the land for hundreds of miles around. People who’d never see it in their whole life nevertheless spent their life working for it. Thousands and thousands of green acres were part of it, forests were part of it. It drew in and consumed….
…and it gave back the dung from its pens and the soot from its chimneys, and steel, and saucepans, and all the tools by which its food was made. And also clothes, and fashions and ideas and interesting vices, songs and knowledge and something which, if looked at in the right life, was called civilization. That’s what civilization meant. It meant the city.
So we can see that a city is also a process as much as a place and includes the immediate area it gains resources from and its products go to, e.g. in the past ¾ of some cities were metal works. From the hinterland come the raw (and sometimes refined) resources, such as wheat, eggs, ore and timber, that a city consumes and out it gives the refined products (like steel, weapons and tools), culture and now days machines/equipment. What can form from this is a symbiotic relationship that enhances both the city and rural communities.
Here’s an example; a village machine shop maybe able to produce almost all the villages needs but lacks the skills, resources and time to make some of its own high precision equipment. Now instead of cutting other services to be able to remake this equipment or losing whatever capability the equipment provides. The machine shop could instead import the equipment from a city, which has far more machine shops, engineering works and the like. The village machine shop could then maintain the equipment without sacrificing capabilities and allow the village to produce more using the machine shops products. This can feed back into greater exports to the city and hence the overall economic activity and technological complexity. This form of symbiotic relationship will be important if we wish to keep a relatively high level of technology/technical skills.
The level of technology is quite important when thinking about sustainability on this scale as the smallest unit shifts as the tech level increases. While at most levels the village is the most basic unit as the tech level rises it becomes the village- town relationship and then the village-town-city complex. If we want an eco-technic future, we need more than eco-villages, at a minium we need eco-towns as well and then eco-cities. This is not to say that village level sustainability isn’t worthwhile, since villages can more easily downshift tech level, simply that to have an eco-technic future, rather than a medieval future, the cities that exist today will need to be involved.