The idea that Earth is a living thing goes back at least as far as Plato, who according to Francis Bacon believed that the planet “was one entire, perfect, living creature.” But it was James Lovelock and his colleague Lynn Margulis who, in the early 1970s, developed a testable scientific hypothesis aimed at investigating Earth’s lifelike properties. Known as the Gaia hypothesis, it states that life on Earth works to keep conditions at the planet’s surface favorable to life itself. In 2006 this led to Lovelock joining the likes of Louis Agassiz and Charles Darwin in receiving geology’s most prestigious prize—the Geological Society’s Wollaston Medal. In presenting the award the society’s president acknowledged that the Gaia hypothesis had “opened up a whole new field of Earth Science study.”
The Gaia hypothesis has now evolved, according to Lovelock, into a full-fledged scientific theory (in science hypotheses are held to be untested ideas put forward to explain facts, while theories have been tested and are generally considered true). Part of the testing came in 2001 when scientists from four international climate research programs reasserted the hypothesis’s basic tenets: (1) Earth “behaves as a single, self-regulating system”; (2) “human activities are significantly influencing Earth’s environment”; (3) Earth’s system is complex and difficult to predict, and “surprises abound”; (4) the system is characterized by “critical thresholds and abrupt changes”; and (5) Earth’s system has “moved well outside the range of natural variability exhibited over the last half million years at least.” Yet despite such support, the transformation of the hypothesis to the status of a theory is still widely disputed.
The Gaia concept and climate change science are intimately connected, and Lovelock has spent most of his career trying to understand the consequences of increased greenhouse gas concentrations in the atmosphere. In his latest book, The Vanishing Face of Gaia: A Final Warning, he argues that Earth’s system of self-regulation is being overwhelmed by greenhouse gas pollution and that Earth will soon jump from its current cool, stable state into a dramatically hotter one. All climatologists acknowledge the existence of such climatic jumps—as occurred for example at the end of the last ice age. But chaos theory dictates that the scale and timing of such leaps are inherently unpredictable, which means that they cannot be incorporated into the computer models of Earth’s climate system that such scientists use to project future climate change. Yet this is precisely what Lovelock attempts to do—using his own computer modeling—in The Vanishing Face of Gaia. A new climatic jump, he concludes, will occur within the next few years or decades, and will involve an abrupt increase in average global surface temperature of 9 degrees Celsius—from 15 to 24 degrees Celsius (59 to 75 degrees …
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