Before cities existed humans were nomadic and harvested food from the landscape though which they walked. Only when agriculture developed could people “settle” in one place. However, agricultural settlement itself is not sufficient to produce a city. It is only when farmers produce food surplus to their own needs that some people can give up farming and do something else. Cities are what people do when they are not growing food (or wandering around trying to find it). Put another way, the most fundamental constraint on cities is their food supply. Without a foodshed, and the energy to transport food to the city from it, a city cannot exit.This reminded my of one of my all-time favorite post on the Of Two Minds blog, reminding us that cities of the past used much less energy and yet were fantastic places to live:
When was the last time you heard an urban planner talk about the food supply? For most urban planners food supply is an “externality”. Is can simply be assumed to happen independent of what happens within a city. But this will not be true in a future, resource-constrained world.
What never ceases to amaze me is how many people seem to have forgotten that great cities flourished without fossil fuels. The capital of the wondrous Tang Dynasty in China (near present-day Xian) contained upwards of 1 million people circa 700-900 A.D., and was a complex entrepot of trade and treasure from distant lands.Read the whole thing here: 1905 San Francisco: Great City, Low Energy Consumption.
The great Thai capital of Ayuttaya also had nearly a million residents in the 1600s and early 1700s before it was sacked and burned by the Burmese army; Westerners had carved out their own small quarters in the sprawling city.
Paris and the other great cities of Europe thrived in the same timeframe (1600s and 1700s) without fossil fuels or high energy-density consumption.
Those who expect (and become furious when their quasi-religious "faith" is questioned) a decline in energy availability to immediately lead to violent chaos overlook how similar life was in 1905 San Francisco, when coal generated (by today's standards) modest amounts of power and biofuel transportation (i.e. horses) were the common form of drayage.
Note the pace of travel via trolley is a slow trot (roughly 8-10 miles per hour), probably faster than much of today's auto-centric traffic.
Yes, the world of 1905 was filled with social injustices, and the overcrowded ghettos of South of Market and Chinatown were wretched. But this film reveals how prosperity was not yet dependent on high consumption of fossil fuels or a transport system totally dependent on oil.
While steam ships powered by coal were the norm in 1905, the age of sail was still within living memory, and there were still old cargo ships (hauling lumber and the like) which were powered solely by sail.
We should also ponder where the food and hay came from to fuel the people and drayage animals in 1905; the farms did not yet depend on petroleum-based fertilizers and the transport was largely water-borne.
The population of San Francisco in 1905 was roughly 400,000--the 1900 Census pegged the number at 343,000. Thus the population was about half the modern total. But we should recall that much of modern-day San Francisco ("the Avenues", etc.) was still sand dunes in 1905.
I was thinking about this the other day. In some circles when they talk about Peak Oil, the advice is you hear is to get the hell away from cities, and that you'd better be living on a farm or else. The idea is that cities will turn into battle zones, as if suddenly all the shelves will be empty. Given urban crime rates and racial tensions, I can understand this inclination, but I think it misses some key points.
I think the reality will be much different. In fact, cities will be where the solutions will come from. Cities cannot afford to ignore problems, and when large amounts of people are together, they will come up with solutions. Already urban gardens are sprouting up in cities. Already car sharing is cropping up in cities. Urban homesteading is on the rise. Many cities have time banks and some even have community currencies. Most cities have farmer's markets springing up everywhere. Cities are where most of our commerce takes place because that's where the money is - and where the markets are. In fact, we could be looking at a world where cities trade with each other while the countryside becomes depopulated. Unless you plan on farming for a living, the city is the place to be to procure what you need to survive. What fossil fuels remain will be coming here first.
I do think there's a "sweet spot" for urban size. I think Milwaukee is ideal: just the right density but not too dense, with plenty of bounty in the surrounding farmlands, and plenty of access to water. If you wanted to, you could find every food you really needed within a few hours of the city; beef, poultry, pork, fish, vegetables, corn, cheese, honey, beer, wine, if not in the city itself. And with pioneers like Growing Power and Sweet Water Organics, Milwaukee is shaping up to be an ideal template for a future American post-carbon city.
BONUS: Lloyd Alter today asks the exact same question.