by Kurt Cobb
Yet the forces which have made all of this migration possible seem like they are coming to an end. The fabulous advances in food production of the last century are slowing. We are having a harder time keeping up with population growth. This is partly the result of a self-reinforcing loop in which more urban growth means more land for housing and infrastructure and the consequent destruction of fertile farmland needed to feed this growing population. The result of this and other factors has been that per capita grain yields which peaked in 1984 have actually declined. Yes, there is overall more food available; but the key figure--as anyone who has gone hungry can tell you--is food per person. Naturally, people eat things other than cereal grains. But for most of the world, cereal grains are the central source of food calories; some 80 percent of all calories eaten are in the form of grain products and the products of livestock fed on grains.
We face a litany of other problems as well: the overuse of underground and surface waters, the collapse of fisheries, climate change, deforestation, loss of biodiversity, toxic pollution, and the depletion of strategic minerals. In addition, the growth in world oil production appears to be stalling out. Yet, against this backdrop, waves of humanity keep washing into the world's cities.
It is like the momentum of the tides which take water further up onto the beach even as the gravitational force which brought that water there is waning. People continue to come into the cities despite all the challenges of doing so because the whole system--even as it frays at the edges--practically forces them to.
Those who are concerned about sustainability talk about making cities more sustainable. But that is an oxymoron. Cities have never been sustainable. They have always needed more from the land than the land under them could give. But the issue is more nuanced than that. On the one hand, living more densely in an energy-constrained world makes sense. It reduces travel for all purposes, economic and social. And, in the past people did live in walkable villages and towns. Some still do. But today, at least in North America, only those living in large cities can really do without a car.
I'd like to see a sustainability study of medieval cities--Mr. Cobb is criticizing all cities everywhere and all times. What is the minimum size that an association must have in order to be considered a city?
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