Waste can be regarded as a human concept as there appears to be no such thing as waste in nature. The waste products created by a natural process or organism quickly become the raw products used by other processes and organisms. Recycling is predominant, therefore production and decomposition are well balanced and nutrient cycles continuously support the next cycles of production. This is the so-called circle of life and is a strategy clearly related to ensuring stability and sustainability in natural systems. On the other hand there are man-made systems which emphasize the economic value of materials and energy, and where production and consumption are the dominant economic activities. Such systems tend to be highly destructive of the environment as they require massive consumption of natural capital and energy, return the end product (waste) to the environment in a form that damages the environment and require more natural capital be consumed in order to feed the system. Where resources and space are finite (the Earth isn’t getting any bigger) this is ultimately not sustainable