Crashes, Crises, and Calamities

If you want the latest news on global warming, for example, you might like to start with Chapter 9, which tells the story of how models have been developed to help us predict future events in complex personal and global scenarios. If you want an up-to-date list of early-warning signs relevant to our daily lives, you might even turn straight to Chapter 11, which gives such a list, beginning with the little-known fact that the height of women's hemlines is a remarkably accurate warning sign of changing economic circumstances.

The task of unearthing this information, putting it into familiar contexts, and applying it to problems that affect us all has been endlessly fascinating. I hope that you enjoy sharing my journey of discovery.

By a singular act of serendipity, the British ecologist Rachel Grant happened to be studying the mating behavior of the toads at the time of the earthquake. She was understandably annoyed when the toads suddenly disappeared from her study site, but thrilled when they returned the day after the earthquake—not just because she could continue her study, but because she was the first scientist to be able to confirm the many anecdotal reports over the centuries of animals acting strangely just before a natural disaster.

Following her scientific account of the phenomenon, there have been suggestions that we could use the behavior of toads or other animals as early-warning signs for earthquakes. Whether this suggestion will withstand scrutiny is not clear, but at least we may be able to discover any physical signals that the animals are responding to and monitor those.

What is clear is that the detection of early-warning signals can make a huge difference to our ability to deal with upcoming crashes, crises, and calamities—not only in the natural world but also in our personal lives and in our social and economic environments. This is especially true for the sorts of events that scientists have labeled as critical transitions.

In these events, things have been going along smoothly, or changing at a comfortable, steady pace, until abruptly, without apparent warning, there is a jump to a very different state. A volcano explodes; a market collapses; a bridge falls down; a relationship blows up; an epidemic takes off; war breaks out. All of these events, in the scientists' terminology, are critical transitions.

In this book I tell the story of mankind's search for warning signs of such events, and how it has culminated with the recent discovery of a set of early-warning signs that are common to critical transitions of all kinds. I show how these exciting discoveries could be of inestimable value in helping us to predict and deal with sudden crashes, crises, and calamities, both in our personal lives and in the world around us.

Mankind has sought warning signs of such events for millennia. Some cultures put their trust in seers and oracles who were believed to be able to "see" the future. Others looked for omens and harbingers of disaster in the form of unusual heavenly events such as eclipses—a belief that strongly resonates with the modern-day belief in the power of economic and social forecasters, who search for unusual social and economic indicators to guide their prophecies.

With the coming of the scientific era, physical laws began to be uncovered that could act as valuable aids to prediction. Galileo was the first off the blocks when he used simple physical principles to calculate how thick the roof of hell would have to be so that it did not collapse in on itself. Later scientists built on Galileo's physical ideas to develop the concept of stress, which engineers use to help predict whether structures like bridges and buildings will be able to support their own weight. This was a considerable advance on the medieval approach of trial and error: a great many cathedrals collapsed during construction or under the influence of the first high wind because the concept of stress was not fully understood.

The physical concept of stress has been "borrowed" by psychologists as an aid to understanding our response to different circumstances. They use it as a measure of the effect that difficult circumstances can have on us, and whether we can cope, or whether we might collapse like the medieval cathedrals.

Stress is not the only conceptual tool that psychologists have borrowed from the physical sciences. An equally important one is feedback, which forms the core of our present understanding about how critical transitions arise.

Feedback comes in two forms—positive and negative. Positive feedback reinforces change; negative feedback damps change down and restores equilibrium. Positive feedback can lead to runaway collapse. Negative feedback maintains the balance.¹

Positive feedback works by reinforcing change, with the strength of the reinforcement increasing as the change increases. This means that the rate of change continuously accelerates—an apparently insignificant initial change can grow to become a catastrophically big one. A ladder that starts to tilt and fall while you are at the top, growing panic in a crowd, a run on a bank, the growth of an avalanche from tiny beginnings, the evolution of an arms race, the runaway collapse of a fragile ecosystem, the increasing violence of arguments in a deteriorating relationship—these are all examples of positive feedback.

Negative feedback works by providing a restoring force that becomes stronger when change threatens to become larger—like the governor on an engine, which gradually closes off the fuel supply as the engine speeds up, or the way we steer a car by turning the wheel to correct any deviations from the line that we want the car to take. Our bodies also use negative feedback in many ways to maintain homeostasis. The hotter we get, for example, the more we perspire, and the greater becomes the cooling effect as the perspiration evaporates.

On a larger scale, it has been proposed that the "balance of nature" and the "invisible hand" of free market competition provide long-term stability by introducing negative feedback into ecosystems and economies, respectively. Unfortunately, it's a myth in both cases. Such negative feedback processes can provide temporary stability, but in the long term our ecosystems and our economies, like our bodies, our relationships, and our societies, are all governed by a complex and constantly shifting balance of positive and negative feedback processes.

Critical transitions happen when positive feedback or some other "runaway" process (such as a buildup of stress) takes over from the normal balancing processes of negative feedback. Our problem in predicting personal, social, economic, and natural disasters is learning how to tell when the balance is stable, on the one hand, and when we are getting dangerously close to a point of instability, on the other. When we get to such a point, intolerable stresses may provoke a sudden collapse, and runaway processes such as positive feedback may suddenly take over and cause the system to run out of control and fail catastrophically.

The underlying processes that produce critical transitions have a lot in common, but until recently the task of predicting the imminence of a critical transition has seemed close to impossible. Sometimes it is genuinely impossible, but in the last decade new insights and the development of increasingly powerful computers have allowed scientists to look more deeply into the question. What they have seen offers fresh hope. Out of a dizzying mess of action and reaction, deviation and correction, process and counterprocess, there has come into focus a remarkable set of universal early-warning signs that tell us when situations are about to become critical and when runaway processes are about to take over.

The signs are similar no matter whether we are talking about social disruption, economic disaster, ecosystem collapse, or climate change and other natural catastrophes. Most of the signs are also simple—simple enough for all of us to understand and take heed of.

Such early-warning signs promise to let us do Monday morning quarterbacking on a Saturday morning by using discoveries from physics, mathematics, and the world of nature to forecast and handle sudden shocks, surprises, and catastrophes, whether in our personal lives or in the world around us.

When I first came across these findings and recognized their profound importance, I realized that this was something we should all know about. I couldn't wait to find out more and to share my discovery.

This book is the result. It tells the story of mankind's search for predictors of disaster and investigates how we might use the recent and still-evolving discovery of a new set of generic early-warning signs to take firmer control of our own future and the future of the planet.

My main aim has been to provide stimulating and thought-provoking ideas from areas that may not be familiar to all readers. I have had to prune and simplify in order to clarify; almost every paragraph could have been expanded into a whole chapter, or even a book. In compensation, there are extensive notes for those who want to pursue particular issues in depth. The notes are an eclectic collection of fascinating anecdotes, references, and additional background information that I came across during my research but couldn't easily work into the main text. They provide an additional dimension and are a detailed resource for those who would like to take up any of the issues I address. Some readers of previous books of mine have even written to say that the set of notes is where they start reading!

Each note is linked to a particular point in the main text, but the notes as a whole are designed to be read independently and also to direct the reader to the most interesting and important original references. I have taken some pains to select the most readable references for the nonspecialist and to add comments when needed. Whether you start with the notes or the main text, I hope that this book stimulates you to think in new and creative ways about your own and the world's future.