As a result of modern agricultural practices, the United Nations has estimated that one-third of the world's remaining arable land will be lost to desertification in the next quarter century. Two-thirds of the pesticides highlighted in Rachel Carson's 1962 classic, Silent Spring, are still being manufactured and used around the world. Modern patterns of food consumption have also had a tremendously negative impact on wilderness lands, deserts, and other ecosystems. One-third of the world's differ ent species of plants and animals are located in these regions and face extinction as a result of modern development. In addition to reducing biodiversity, clearing of the rain forests for pasture contributes to global warming.
Trees absorb carbon dioxide, the principal greenhouse gas.
Livestock production also produces methane, another greenhouse gas which contributes up to 10 percent of global warming. If this trend continues, temperature rises over the next several decades will cause tremendous climatic and meteorological changes, including possible melting of polar ice caps, rise of sea levels, and inundation of coastal regions in which hundreds of millions of people live. By changing to a more natural and organic food and agricultural system, the world's farmland could be regenerated, the environment could be preserved, and global warming forestalled. Monoculture would gradually be replaced with mixed crops. Heavy mechanical cultivation would give way to small-scale appropriate technological methods, and chemical fertilizers and insecticides would be retired in favor of organic compounds and wastes.