William H. Calvin, a theoretical neurophysiologist at the University of Washington at Seattle, has written nine books, including How Brains Think and The Cerebral Code. But he also maintains a punishingly busy schedule as a researcher, investigating how brains work and evolve, and travels extensively on the lecture circuit. Readers would therefore also be forgiven for wondering why Calvin devotes so much of his precious time to following the study of climate change. This article, although written in 1998, is well done with good science and great illustrations.
William H. Calvin
The Atlantic Online
The answer, Calvin says, is that the evolution of the human mind is intimately linked to abrupt climate change: our brains seem to have begun their transformation from apelike to fully human just when temperatures on earth began their current trend of jumping rapidly—often within a single lifetime—between warm and cold. Calvin argues that in the context of brief environmental opportunities (periods of warmth) and hazards (sudden icy temperatures), survival for our ancestors became dependent on having highly agile, “jack-of-all-trades” minds. The flip-flop of climates, in other words, led to the evolution of brains that could themselves flip-flop abruptly between strategies for survival. In describing the minds that we have ended up with, Calvin is fond of referring to a passage by William James that appeared in The Atlantic Monthly in October, 1880. “Instead of thoughts of concrete things patiently following one another,” James wrote,
We have the most abrupt cross-cuts and transitions from one idea to another, the most rarefied abstractions and discriminations, the most unheard-of combinations … we seem suddenly introduced into a seething caldron of ideas, where everything is fizzling and bobbing about in a state of bewildering activity.
Creative thinking is now more important than ever. A central point in “The Great Climate Flip-flop” is that the greenhouse gases we pump daily into the atmosphere may well trigger an abrupt global cooling. But if we have helped to bring on such a problem, we are also the only creatures on the planet with brains highly enough evolved to solve it—and solve it we must, even if, as Calvin points out, it won’t make our brains any larger.
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One of the most shocking scientific realizations of all time has slowly been dawning on us: the earth’s climate does great flip-flops every few thousand years, and with breathtaking speed. We could go back to ice-age temperatures within a decade—and judging from recent discoveries, an abrupt cooling could be triggered by our current global-warming trend. Europe’s climate could become more like Siberia’s. Because such a cooling would occur too quickly for us to make readjustments in agricultural productivity and supply, it would be a potentially civilization-shattering affair, likely to cause an unprecedented population crash. What paleoclimate and oceanography researchers know of the mechanisms underlying such a climate flip suggests that global warming could start one in several different ways.
For a quarter century global-warming theorists have predicted that climate creep is going to occur and that we need to prevent greenhouse gases from warming things up, thereby raising the sea level, destroying habitats, intensifying storms, and forcing agricultural rearrangements. Now we know—and from an entirely different group of scientists exploring separate lines of reasoning and data—that the most catastrophic result of global warming could be an abrupt cooling.
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Stabilizing our flip-flopping climate is not a simple matter. We need heat in the right places, such as the Greenland Sea, and not in others right next door, such as Greenland itself. Man-made global warming is likely to achieve exactly the opposite—warming Greenland and cooling the Greenland Sea.
A remarkable amount of specious reasoning is often encountered when we contemplate reducing carbon-dioxide emissions. That increased quantities of greenhouse gases will lead to global warming is as solid a scientific prediction as can be found, but other things influence climate too, and some people try to escape confronting the consequences of our pumping more and more greenhouse gases into the atmosphere by supposing that something will come along miraculously to counteract them. Volcanos spew sulfates, as do our own smokestacks, and these reflect some sunlight back into space, particularly over the North Atlantic and Europe. But we can’t assume that anything like this will counteract our longer-term flurry of carbon-dioxide emissions. Only the most naive gamblers bet against physics, and only the most irresponsible bet with their grandchildren’s resources.
To the long list of predicted consequences of global warming—stronger storms, methane release, habitat changes, ice-sheet melting, rising seas, stronger El NiÒos, killer heat waves—we must now add an abrupt, catastrophic cooling. Whereas the familiar consequences of global warming will force expensive but gradual adjustments, the abrupt cooling promoted by man-made warming looks like a particularly efficient means of committing mass suicide.