The Big Picture:
Human Dependence on Nature
Energy is life, or at least the prerequisite for life. We depend on Nature for the energy that powers the crops in our fields, the animals in our farms and the pets in our homes. We depend on it even for the energy that powers our own bodies. All the fossil fuels that power our civilization are carbon compounds trapped by photosynthesis in past ecosystems and preserved (fossilized) as fossil fuels millions of years ago. The petrol and diesel that power our cars and the coal that is burnt to make electricity makes use of an energy preserved from hundreds of millions of years ago, where the energy-rich long chain organic compounds created by photosynthesis survive in a condensed and fossilized form today as oil and coal. Our planet is bathed in a life-giving stream of energy flowing from the Sun. Through the wonder of photosynthesis, plants trap 1-2 per cent of the sunlight that falls on them (Hall and Rao 1999). This powers almost all of Earth's ecosystems, the only exceptions being bacteria known as chemo-autotrophs that derive their energy from converting energy-rich chemicals in rocks (such as sulphur). So the Egyptians had it right - the Sun is the font of life. Its light drives almost all the living world.
Haydn Washington, Human Dependence on Nature (2012) p.5