The relationship of all this to human life on the planet--to civilization and to the society in which we live--is obvious.

Human beings, like all other forms of life, exist as part of an interconnected food (or energy) web. The basis of the food web is plants, which make their own organic carbon building blocks from CO2. This is where the food web begins, and the energy of sunlight is passed from plant to animal to animal and so on down the line. Some animals eat plants, and some animals eat the animals that eat the plants. But whether an organism occupies the first, second, or third link on the web chain, the energy it uses ultimately derives from the sun, and its body and waste products are utilized by other life forms, and so on. By powering photosynthesis, the sun gives us both the building blocks of life and the fuel to make them function.

Through civilization, human beings have placed themselves at many points in the food web. Scientists estimate that the five and half billion human beings alive today consume approximately 40% of the entire biomass produced annually by the planet.