posted 15 December 2002


William H. Calvin, "Phi Beta Kappa book prize for science" acceptance speech, Washington DC (6 December 2002). See also

William H. Calvin 
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 University of Washington



My book A Brain for All Seasons: Human Evolution and Abrupt Climate Change (University of Chicago Press 2002 ) won the Phi Beta Kappa book award for science.  Here's my speech for the book award dinner:

It is difficult to make brief remarks on a book about how climate lurches resonate with punctuated equilibria to accelerate human brain evolution... but I just happen to have in my pocket some op-ed-sized remarks that I always take along when visiting DC, on the off chance that someone will invite me in off the street -- say, Pennsylvania Avenue -- and ask what I think a science advisor ought to be saying these days.

Shocks and Instability

A Machiavellian advisor to a president might note that scientists are always handy when you need an excuse to postpone action.  We’re professional skeptics, and can always find holes in any proposal.  (You say you figured that one out already, all by yourself?)  Yes, but the physician who waits until dead certain of a diagnosis before acting may wind up with a dead patient.  Sometimes things develop so rapidly that only early action – back when you’re still somewhat uncertain – stands a chance of being effective, as in catching cancer before it metastasizes.

       When the patient is civilization itself, science can provide a heads-up – but only the best politicians have the talent to implement the foresight.  And coming on stage now is a stunning example of how civilization must rescue itself.  Looked at one way, the story is about abrupt climate change – but similar lessons about shocks and instability likely apply to our current problems with suicidal terrorists.

       Another major climate story is now emerging, and it dwarfs the three big scientific alerts from the 1970s about global warming, ozone loss, and acid rain.  (Yes, it really has been thirty years.)  But until the 1990s, no one knew much about abrupt climate change, those past occasions when the whole world flipped out of a warm-and-wet climate like today’s into the alternate mode, which is cool, dry, windy, dusty.

       There are big alterations in only 3-5 years.  It’s as sudden as a drought – which it is.  We once thought of climate change as gradual, like ramping up a dimmer switch.  That’s the usual greenhouse warming notion.  But now we know that some climate change is more like the ordinary light switch that flips abruptly. Dozens of these flips have recently been discovered in ice cores and layered sediments around the world.

       In scope, a flip looks like a worldwide version of the Oklahoma Dust Bowl of the 1930s.  A few centuries later, the drought climate flips back into worldwide warm-and-wet, even more quickly.  Unlike greenhouse warmings, the big flips have happened every few thousand years on average, though the most recent one was back before agriculture in 10,000 B.C.

       Were another climate lurch to happen in today's world, with a population six thousand times greater than on the last occasion, agriculture could no longer feed the city populations.  People would flee into the countryside, eating everything in sight, and losing much of the societal organization needed for prompt recovery.

       "The bigger they are, the harder they fall" will likely apply, with a vicious downward spiral into the Four Horsemen of the Apocalypse:  famine, pestilence, war, death.  It probably won’t be the end of human beings but genocide will be widespread in this vast downsizing.  Just recall Bosnia or Rwanda, multiply by ten, and imagine the whole ruined world affected by such hatred.  Recovery from that hell would take many, many generations.

       Can we head off the next flip, or perhaps slow it down?  After all, were the same climate changes spread out over 500 years, and not such a shock, there might be a technofix, one that would counter the tendency to collapse like a house of cards.  Flips have a Rube Goldberg chain of causation and, in medicine, that is good news, as it provides a number of intermediate stages at which you can intervene.  How much time do we have, then, to develop this preventative medicine of climate that guards against sudden shocks?

       Alas, the next flip may arrive sooner than otherwise, thanks to our current warming trend.  The northern extension of the Gulf Stream appears quite vulnerable to global warming in four different ways.  That’s important because it fails in a flip – some suspect it is even the cause of the flip.  An early warning might be a decline in this current.  And according to two oceanographic studies published this last year, this vulnerable ocean current has been dramatically declining for the last 40-50 years, paralleling our global warming and rising CO2.

       Some optimists say, from what little is known about the climate feedback mechanisms, that we might be immune to the usual flips for awhile.  I hope they are right, but a possible "out" is not something to bet our civilization on.  As the new National Research Council report Abrupt Climate Change says dryly, "denying the likelihood, or downplaying the relevance of past abrupt events, could be costly."

       It is now clear that climate is like a drunk.  If left alone, it sits.  Forced to move, it staggers.

       While climate flips are a particularly dramatic setup for the failure of civilization, other sudden shocks might set off much the same scenario, where people flee the cities and destroy the remaining efficient agriculture before starving.  Epidemic disease in big cities could trigger much the same thing.  So could a widespread economic collapse.  Asymmetrical warfare may not yet be capable of starting a climate flip, but we certainly have acquired suicidal enemies whose shock tactics aspire to trigger epidemic and economic catastrophes.  But their victims might become the whole world, as many interdependent countries, unable to feed their large populations, slide down the slippery slope into genocidal downsizings.

       We must shore up the foundations of civilization well in advance, much as the medieval cathedrals had flying buttresses retrofitted.  What to do is a much longer story, but getting started now is important because political consensus takes so long to achieve.  The development of atomic bombs required only a few years, yet Europe’s impressive achievement of a common currency nonetheless took fifty years.  Often action is nimble while effective reaction is only slowly achieved.

       While scientists can provide better headlights to spot the turnings and the washouts in advance, consensus-building requires a different set of skills.  Only an effective combination of foresight and leadership stands a chance of building those flying buttresses that are needed to protect the cathedral of civilization from abrupt shocks.

       I think that political leadership has the harder task, given how difficult it is to make people aware of what must be done and get them moving in time.  It’s going to be like herding kittens, and the political leaders who can do it will be remembered as the same kind of geniuses who pulled off the American Revolution.

William H. Calvin

Affiliate Professor of Psychiatry and Behavioral Sciences, University of Washington, Seattle.  Author of A Brain for All Seasons:  Human Evolution and Abrupt Climate Change and the Atlantic Monthly’s cover story, “The great climate flip-flop.”



         R. B. Alley et al, "Abrupt Climate Change," Science (28 March 2003).

         B. Hansen et al, “Decreasing overflow from the Nordic seas into the Atlantic Ocean through the Faeroe Bank channel since 1950,” Nature 411:927-930 (2001).

          B. Dickson et al, “Rapid freshening of the deep North Atlantic Ocean over the last four decades,” Nature 416:832-837 (2002).

          Committee on Abrupt Climate Change, National Research Council,  Abrupt Climate Change: Inevitable Surprises (National Academy Press, 2002).

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To order a copy of one of my more recent books, click on a cover for the link to 

A Brain for All Seasons, 2002
A Brain for All Seasons

Lingua ex Machina:  Reconciling Darwin and Chomsky with the Human Brain (Calvin & Bickerton, 2000)
Lingua ex Machina

The Cerebral Code:  Thinking a Thought in the Mosaics of the Mind (1996)
The Cerebral Code

How Brains Think:  Evolving Intelligence, Then and Now (1996)
How Brains Think

Conversations with Neil's Brain:  The Neural Nature of Thought and Language (Calvin & Ojemann, 1994)
Conversations with
Neil's Brain

The River That Flows Uphill
The River That
Flows Uphill


The Throwing Madonna:  Essays on the Brain
The Throwing Madonna

copyright ©2002 by William H. Calvin

William H. Calvin
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