Farming Changes the Game
Roughly 10,000 years ago, the introduction of farming marked a dramatic shift in the human diet and in our relationship to the earth. This shift is thought to have started in the 'Fertile Crescent' between the Tigris and Euphrates Rivers in what is now Iraq. (It is a sad commentary that the Fertile Crescent was recently the scene of a war called the 'Desert Storm'). Observant ancestors realized that seeds from annual grasses related to wheat and barley would produce reliable and abundant crops when planted in the rich alluvial soil of the river flood plains. This technique was refined and extended to other food plants. At nearly the same time we learned to pen up animals to make hunting them a simpler more efficient operation.
Throughout the world, hunting gradually evolved into animal husbandry and gathering evolved into farming. By learning to control the food supply, agriculture created a huge increase in the amount of food available for humans. Unfortunately, the increase in the total amount of available food has been mirrored by a sharp decline in the variety of foods we eat. By the mid-twentieth century, the thousands of species of edible plants and the hundreds of local varieties of fruits and vegetables had diminished to a small handful of the most productive and most profitable.
The effects of this new approach to food production had the most profound effects on human cultures and on the earth's ecology. As we learned to control the available food supply and to store the excess production of grain in containers, a new motive for hard work was created. Food gradually became more limited by labor shortages than by natural resources. It became economically justifiable to use slaves to produce more food and armies to protect it. Controlling our supply of food led directly to a steadily increasing human population and indirectly to centralized power structures and theologies that recognized the new human dominion over other life forms.
Generally speaking, ecosystems tend to evolve towards complexity and stability, with a large number of interdependent species efficiently cycling nutrients and conserving the energy that enters the system. As the agricultural revolution accelerated and the grip of human control tightened, natural ecosystems underwent a profound de-evolution.
Monocultures of a few annual crops replaced more stable and more diverse stands of perennial plants and became the norm. We created vast immature ecosystems similar to those created by the rapid colonization of flooded or burnt land by quick seeding pioneer plants, such as pigweed, ragweed and lambsquarters. Within the river flood plains these annual cropping systems worked relatively well because the land was flat and the soil fertility was periodically replenished by silt from flooding. However, as human populations grew, people were forced onto new lands that were not as well suited for their agricultural system based on intensive planting of annual crops. On sloping land this agricultural system was so unstable that soil loss per acre was (and still is) often a thousand fold greater than it is from the native forests.