In a very real sense, we're all made out of sunlight. Sunlight is the source of almost all life on Earth. Many people I meet believe that plants are made up of the soil in which they grow. That's a common mistake. A tree, for example, is mostly made up of one of the gases in our air (carbon dioxide) and water (hydrogen and oxygen). Trees are solidified air and sunlight.
Animals, including humans, cannot create tissues directly from sunlight, water, and air, as plants can. Thus the human population of the planet has always been limited by the amount of readily available plant food (and the supply of animals that eat plants).
Something important happened about 40,000 years ago: humans discovered they could domesticate ruminant (grazing) animals like goats, sheep, and cows that convert daily sunlight captured by scrub and wild plants on “useless” land into animal flesh, which humans could eat.
About this time, we also figured out that we could replace forests with farmland. Because we had discovered and begun to use herding and agriculture to convert the sun's energy into human food more efficiently, our food supply grew and the human population started growing faster.
Within a few thousand years we also discovered how to extract mineral ores from the Earth, to smelt pure metals from them, and to build tools, such as plows and scythes, that made us much more productive farmers. So the period from 8,000 B.C. until around the time of Christ saw the human population of the world increase from 5 million people to 250 million people. But we were still only using about one year's worth of sunlight-energy per year, and our impact on the planet remained minimal. We weren't “dipping into our savings” to supply our needs, yet.
. . . . .The article in YES! was adapted by permission of the publisher from The Last Hours of Ancient Sunlight
by Thom Hartmann, copyright (c) 1998, 1999, 2004 by Mythical Research, Inc. Used by permission of Harmony Books, a division of Random House, Inc.
However, we do not have the rights to put the full article on the web. To read the complete article, you will need to obtain a print version of the fall 2004 issue YES! Or, we strongly recommend reading the book.