can repeat the question, but am I bright enough to ask it?"
But only a dozen years ago, no one knew much about abrupt climate change, those past occasions when the whole world flipped out of a warm-and-wet mode like today into the alternate mode, which is cool, dry, windy, dusty.
When the patient is civilization itself, science can provide a heads-upbut 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 changebut 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 only a dozen years ago, no one knew much about abrupt climate change, those past occasions when the whole world flipped out of a warm-and-wet mode like today into the alternate mode, which is cool, dry, windy, dusty.
In abrupt climate change you see big alterations in only 3-5 years, as sudden as a droughtwhich it is. We once thought of climate change as gradual, like ramping up a dimmer switch (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. 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 downsizingand not just on the scale of the genocide recorded in the Old Testament or the Greek versions deplored by Thucydides. Just recall Bosnia or Rwanda, multiply by ten, and imagine the whole ruined world affected by such hatred. Recovery from that hellish state of affairs would take 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 chain of causation and, in medicine, this is good news, as it provides a number of intermediate stages at which you can intervene. How much time do we have, 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. 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 took fifty years. Action and effective societal reaction have very different time scales.
While scientists can provide better headlights to spot the turnings and the washouts in advance, speeding up 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 seen as the same kind of geniuses that pulled off the American Revolution.