ABSTRACT
Human health is directly tied to the availability of energy, be it the solar energy captured in the food we eat (calories), the cooking fi re we need for safe consumption, the hearth for keeping warm and dry, the muscle power of grazers harnessed to work the land or the oil and gas that fuel the hospitals, pharmaceutical industry and doctor’s offi ces. For the vast majority of our existence on Earth, humans have depended on solar energy captured by the plants and animals. Today, in the modern industrial world, we are no less dependent on solar energy than were our distant ancestors; it is just that we’ve come to expect instantly available energy, mainly from fossil fuels, the concentrated solar energy of eons ago.
