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W ith the birth of Gaia theory in the mid-1960s, a new worldview began to emerge in Western science. Or rather, ancient ways reemerged, with a modern twist. In this holistic view, life-forms combined, congealed, and otherwise clumped together to form bigger systems. The holistic view came to embrace cells, ecosystems— even planets. The world was alive. Mother Earth had reincarnated as Gaia. Once the Greeks’ vision of the Earth goddess, Gaia now had a decidedly space-age Xair. While seeking evidence of life on other planets, British chemist James Lovelock had recognized her through the mists. He’d seen her face in an atmosphere that deWed entropy. He identiWed the Earth—Gaia—as the world’s largest life-form, a composite of smaller systems that emerged as a living system in its own right. At the other end of the spectrum, the American microbiologist Lynn Margulis had peered down at paramecia and other one-celled creatures and found them teeming with life, a universe unto themselves. The worldview captured by these two holistic approaches at opposite extremes also built upon the momentum of a growing understanding about medium-sized systems. Ecologists had already shown that life-forms cooperated in complex ways in rain forests, prairies, coral reefs, and other ecosystems. Still, applying this holistic view to the planet required vision and courage. Lovelock’s version of Gaia only loosely relates to the Greeks’ vision of the Earth goddess. As with most of the gods and goddesses in their pantheon, Gaia’s life in Greek myth resembled a soap opera more than a spiritual treatise. Born of Chaos, she gives birth to Uranus, identiWed variously as the universe and the sky. With Uranus’s fertile rains, she gives birth to the mountains and seas and other earthly creations, including a host of children. Some Greek concepts of Gaia had aspects in common with the modern view, though. As Bruce ScoWeld noted in Scientists Debate Gaia, the philosopher Thales of Miletus, who lived in the sixth Y 2 Z A Living System Gaia and Climate Control century B.C., saw the world as an organism—speciWcally an animal. Thales and his contemporaries, including Pythagorus, embraced the concept of a living Earth they called anima mundi. Many cultures outside of Greece also featured the concept of the Earth as a living being, typically a bountiful female. Some indigenous American cultures have sacred teachings featuring both Mother Earth and Father Sky—an interesting overlap with the Greek’s concept of Gaia and Uranus/Sky (without the Oedipal overtones). In Colombia and other South American countries, people honor the Earth goddess Pachamama. Celtics honor Danu. Pagans in general honor local versions of Mother Earth, as do Hindus and some other Asian cultures. Lovelock could have bypassed some of the spiritual connotations by naming his theory Biocybernetic Universal System Tendency/Homeostasis, which he had considered. At the suggestion of neighbor William Golding, author of Lord of the Flies, he settled on the more poetic and succinct Gaia in the early 1970s. It suited the colorful spirit of the times. Anyway, as Lovelock likes to point out, the goddess Gaia is also known as Ge—as in geology, geography, and what he sometimes calls the Weld of geophysiology. The twentieth-century version of Gaia includes an important scientiWc reWnement. Lovelock established that life plays an important role in moderating Earth’s climate. Methods include manipulating atmospheric gases, changing the planet’s ability to reXect sunlight, and releasing compounds that help seed raindrops. Gaia theory starts from the premise that the Earth’s climate has remained relatively stable despite an ongoing increase in solar power. Like every star, the center of our solar system— Sol—starts out using hydrogen for power. Then it gradually turns to helium, which tends to burn hotter. After observing other suns, astronomers estimated that Sol has probably warmed by about a quarter since life Wrst began on Gaia. What’s more, the position of Earth in relation to the sun changes in regular cycles related to its orbit and tilt. These Milankovitch cycles, as they’re known, affect how much solar energy reaches Earth’s surface. They help explain the timing of ice ages and hothouses over the past 2 million years or so (as the next chapter will explain). Despite the sun’s ongoing warming and orbital Xuctuations in the amount of solar energy reaching Earth, Gaia manages to maintain its temperature within a range suitable for life. Lovelock...

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