Long term agricultural overshoot

According to Peter, humanity has probably been in overshoot of the Earth’s carrying capacity since it abandoned hunter gathering in favor of crop cultivation (~ 8,000 BCE). The problem is that soil needs tightly woven natural ecosystems to properly recycle nutrients and prevent soil erosion. Earth’s inhabitants have devised a whole series of approaches to increase the amount of food that can produced, starting first with hand-cultivation and culminating in the last century with the widespread use of fossil fuels. These approaches strip the soil of its nutrients and cause soil erosion. Even Permaculture cannot be expected to overcome these problems. According to the paper, eventually, to reach sustainability, the world will need to reduce its population to that of the hunter-gathers, and go back to living on the resources the natural ecosystems can produce.

Part 1: Life Before Agriculture

The major departure for humans as just another member of the global animal species assemblage came when fire was first used about 400,000 years ago by Homo erectus (Price 1995). The dynamic cyclical stability of complex systems has been shown for most animal populations, except top predators, to depend on predation to dampen overshoot and runaway consumption dynamics of prey species (Rooney et al. 2006). The ability to control and use fire removed the influence of wild animal predators as moderators of human numbers. The use of fire made possible the colonization of cold lands at high latitudes where fuel for heating shelters was available in some form such as animal oil, dried dung and wood. Even though their shelters became more complex and elaborate, they were, for the most part, temporary encampments whose main structural components could be transported across the landscape so as to benefit from variable food availability as the seasons changed.

The bulk of human history has been that of a culture of hunter gathers or foragers. They did not plant crops or modify ecosystem dynamics in any significant manner as they were passively dependent on what the local environment had to offer. They did however domesticate dogs as early as 100,000 BCE (Vila et al. 1997); these animals were useful as hunting aids, guardians, and occasionally as food during times of scarcity. Hunter gatherers maintained social organization and interdependence, and prevented the loss of food to spoilage by sharing the harvest among community members. These people lived in harmony with their supporting ecosystems and their ability to unsustainably stress and damage their environment was limited by the fact that if their numbers exceeded the carrying capacity of the complex, self-managing, species diverse, resilient terrestrial and aquatic ecosystems from which they gained their sustenance, then hunger and lower fertility exercised negative feedback controls on further expansion.

http://www.theoildrum.com/node/6048