As far as food is concerned, the great extravagance is not caviar or truffles, but beef, pork and poultry. Some 38 percent of the world's grain crop is now fed to animals, as well as large quantities of soybeans. There are three times as many domestic animals on this planet as there are human beings. The combined weight of the world's 1.28 billion cattle alone exceeds that of the human population. While we look darkly at the number of babies being born in poorer parts of the world, we ignore the over-population of farm animals, to which we ourselves contribute...[t]hat, however, is only part of the damage done by the animals we deliberately breed. The energy intensive factory farming methods of the industrialised nations are responsible for the consumption of huge amounts of fossil fuels. Chemical fertilizers, used to grow the feed crops for cattle in feedlots and pigs and chickens kept indoors in sheds, produce nitrous oxide, another greenhouse gas. Then there is the loss of forests. Everywhere, forest-dwellers, both human and non-human, can be pushed out. Since 1960, 25 percent of the forests of Central America have been cleared for cattle. Once cleared, the poor soils will support grazing for a few years; then the graziers must move on. Shrub takes over the abandoned pasture, but the forest does not return. When the forests are cleared so the cattle can graze, billions of tons of carbon dioxide are released into the atmosphere. Finally, the world's cattle are thought to produce about 20 percent of the methane released into the atmosphere, and methane traps twenty-five times as much heat from the sun as carbon dioxide. Factory farm manure also produces methane because, unlike manured dropped naturally in the fields, it dies not decompose in the presence of oxygen. All of this amounts to a compelling reason...for a plant based diet.
You think man can destroy the planet? What intoxicating vanity. Let me tell you about our planet. Earth is four-and-a-half-billion-years-old. There's been life on it for nearly that long, 3.8 billion years. Bacteria first; later the first multicellular life, then the first complex creatures in the sea, on the land. Then finally the great sweeping ages of animals, the amphibians, the dinosaurs, at last the mammals, each one enduring millions on millions of years, great dynasties of creatures rising, flourishing, dying away -- all this against a background of continuous and violent upheaval. Mountain ranges thrust up, eroded away, cometary impacts, volcano eruptions, oceans rising and falling, whole continents moving, an endless, constant, violent change, colliding, buckling to make mountains over millions of years. Earth has survived everything in its time. It will certainly survive us. If all the nuclear weapons in the world went off at once and all the plants, all the animals died and the earth was sizzling hot for a hundred thousand years, life would survive, somewhere: under the soil, frozen in Arctic ice. Sooner or later, when the planet was no longer inhospitable, life would spread again. The evolutionary process would begin again. It might take a few billion years for life to regain its present variety. Of course, it would be very different from what it is now, but the earth would survive our folly, only we would not. If the ozone layer gets thinner, ultraviolet radiation sears the earth, so what? Ultraviolet radiation is good for life. It's powerful energy. It promotes mutation, change. Many forms of life will thrive with more UV radiation. Many others will die out. Do you think this is the first time that's happened? Think about oxygen. Necessary for life now, but oxygen is actually a metabolic poison, a corrosive glass, like fluorine. When oxygen was first produced as a waste product by certain plant cells some three billion years ago, it created a crisis for all other life on earth. Those plants were polluting the environment, exhaling a lethal gas. Earth eventually had an atmosphere incompatible with life. Nevertheless, life on earth took care of itself. In the thinking of the human being a hundred years is a long time. A hundred years ago we didn't have cars, airplanes, computers or vaccines. It was a whole different world, but to the earth, a hundred years is nothing. A million years is nothing. This planet lives and breathes on a much vaster scale. We can't imagine its slow and powerful rhythms, and we haven't got the humility to try. We've been residents here for the blink of an eye. If we're gone tomorrow, the earth will not miss us.