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Actually it’s the so-called feedback loops that have tripped up scientists so badly, causing the experts to wildly misjudge the speed of the climate crash. Having never witnessed a planet overheat before, no one quite anticipated the geometric rate of change. To cite one example, when that brilliantly white Arctic ice melts to blue ocean, it takes with it a huge measure of solar reflectivity, which increases sunlight absorption and feeds more warmth back into the system, amplifying everything dramatically. And as northern forests across Canada continue to die en masse due to warming, they switch from being net absorbers of CO₂ to net emitters when forest decomposition sets in. And as tundra melts all across Siberia, it releases long-buried methane, a greenhouse gas twenty times more powerful than even CO₂. And so on and so on and so on. Like the ear-splitting shriek when a microphone gets too close to its amplifier, literally dozens of major feedback loops are screeching into place worldwide, all at the same time, ushering in the era of runaway climate change.

“Only in the past five years, as researchers have learned more about the way our planet works, have some come to the conclusion that changes probably won’t be as smooth or as gradual as [previously] imagined,” writes Fred Pearce in his new book With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change. “We are in all probability already embarked on a roller coaster ride of lurching and sometimes brutal change.”