We started out as human beings with the need to tame solar energy to get our food. Sunlight is distributed over the entire planet, maybe not quite evenly but there is sufficient sunlight most everywhere to sustain us, and we had to develop systems and societal rules to use it properly. And in fact that is how human societies developed, the whole idea of property and wealth had its origins in agriculture and food, based on harnessing solar energy to grow things, both as food for people and subsequently as food for animals. [The fish eaters were going their merry way, and had a different series of rewards associated with catching the fish].
But sometimes about three hundred years ago we started using fossil fuels instead of solar energy, and as this took off, particularly in the 20th century, the whole balance of things changed. So now the power to support agriculture is not spent on the farm but in the cities where there are factories to manufacture chemicals, build tractors and other farm machinery, in universities and industrial laboratories where new varieties are developed, to make fertilizers, and to provide the input and output systems, all the logistics to buy, distribute and sell the food.
As the great anthropologist Howard Odum put it in his classic book, Environment Power and Society, 'as we stand on the edge of the vast fields of grain with tractors and production as far as the eye can see, we are tempted to think that man has mastered nature, but the plain truth is that he is overcoming bottlenecks and providing subsidy from fossil fuel. As he said, we now eat potatoes made mostly from oil. He mused that 'the citizen in the industrialized country thinks he can look down upon the system of man, animals, and subsistence agriculture that provides some living from an acre or two in India when the monsoon rains are favorable. Yet if fossil and nuclear fuels were cut off, we would have to recruit farmers from India and other developing world countries to show the now affluent citizens how to survive on the land while the population was being reduced by a hundred fold to make it possible.' And here is another interesting observation: we have completely changed the systems by which we provide ourselves with food, but we have hardly changed the systems of societal organization in response to this.
I recently did a radio program on some of the environmental issues around food and you can get it from itunes for free from http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewPodcast?id=319560376