The precautionary principle tells us that when catastrophe is a possibility, it is wise to act to prevent it, rather than waiting to gather more information on likelihood, writes Alex Kazemi.

In the photo, Robert Pershing Wadlow is smiling. He stands next to his stern faced father, leaning crookedly from the waist, his legs reaching higher than his father’s shoulders. At 8 feet 11 inches, the Guinness Book of Records declares Robert Wadlow to be the tallest man to have ever lived, at least in verified history. He lived until the age of 22 but, despite his relative celebrity, you will find only a handful of archived photos of him. Each one is carefully staged, a posed diorama of cameo appearances around him, with only brief explanatory captions. In an age where even the most ordinary existences become a flip book of thousands of digital photos flashing through the ether, it feels strange to peer distantly into scattered fragments of a life lived at an extreme. 

We’ve always been fascinated by extremes but we’d been accustomed to viewing them from the shelter of our average lives. In the last couple of years the world has been sent spinning out to the edge. In January 2020, outspoken statistician Nicholas Nassim Taleb co-authored a warning that if countries didn’t employ the precautionary principle in decisively closing down the spread of the emerging novel coronavirus, then a global pandemic was inevitable. He was not the only one to issue the warning but it went unheeded for much too long by a number of governments including those of the UK and the US. 

Taleb’s position came from his research into the risk of extreme global events and his strong belief that the probability of these events is misunderstood. He calls these events “ruin problems”, by which he means to say that they can be catastrophic for humanity. If not this one now, then one in the future. In this moment, his language might feel uncomfortable. We will get through this pandemic, albeit with great loss globally, but it needs to be an alarm signal. We need to give uncertainty the respect it is due because, as Taleb points out, our civilisation is more fragile to these risks than we choose to believe. 

In pandemic terms the precautionary principle means that where there is a potentially catastrophic outcome of an event, even with uncertainty about the exact chance of it occurring, it is wise to act to prevent it, rather than waiting to gather more information on its likelihood. Critics of the principle argue that it is unnecessarily cautious. This is both a misunderstanding of the situations in which it should be used as well as what it does. The paradox is this then – the best thing to happen, when it is properly used, is that nothing happens. It might feel strange for a world that has, up to this pandemic, been constantly hurling itself forwards, to hit the brakes. To those that are troubled by the intangible all we have after that is the counterfactual, the what-might-have-happened-otherwise. Though in the case of Covid-19, we now have plenty of tangible grim news from overseas to construct those counterfactuals for ourselves.

The underpinning theories are to do with probability and came into public prominence through the global financial crises of the early part of this century. Randomness, and probability, makes the shape of our world more blurry than we like to think it is. We can map out the chances of discrete events occurring into what are called probability distributions, the most well-known of which is the “normal” distribution or bell curve. The salient feature of this is that most of the values tend to cluster around a central average, whereas the left and right ends of the bell, known as the tails, contain relatively few events and disappear to zero very quickly. This last point puts it in the group of what are known as thin tailed distributions. Extreme events are both few in number and limited in how extreme they can be. 

For a lot of naturally occurring characteristics, such as the spread of heights in a population, they work well enough. The heights of most people you meet will tend to be clustered around an average value. Nearer the edges you will know a few people you think of as very tall. But only a handful of people in history would approach the height of Robert Wadlow and there is zero chance of anyone being 12 feet tall, in the normal order of things. 

They tend to arise as the result of many small random events; life lived at the casino table. If a roulette ball lands on red four times in a row you should shrug. Thrown enough times on a fair wheel it will land on red and black equally often. Events tend towards the average in the long run; the lucky streak comes to an end; the house always wins. But it turned out they were disastrously wrong when applied to interconnected systems like global finance. 

This was already understood within science but largely unappreciated outside it. In the 1960s the mathematician Benoit Mandelbrot, who became famous for the fractal beauty of his Mandelbrot set, found that changes in cotton prices followed what is called a heavy tailed distribution. In these, there is a higher chance of extreme events occurring than in thin tails, and the extremes themselves can be much larger. These distributions can be applied to many other measurements in the real world such as the size of cities and Twitter networks. For some types of event, the tails are heavy with potential disaster – earthquakes, wars, wildfires and pandemics, to name a few.

While there is ongoing debate as to the mathematics used to describe each one, the common thread is that they arise out of complex systems, often human made. A high degree of connectivity between the various points means that we are not viewing independent events but rather each part can be connected to many others. The hallmark of these systems is that the way they move isn’t easily predictable from the starting point and they may lead to tipping points where the system can suddenly explode into the extreme. These arrangements are not intuitive for us. We tend to think in a linear fashion from A to B, fixating on the flame moving along the trail of gunpowder without thinking about the powder keg it leads to. 

We can find the maths challenging yet still understand what it means for how we act. In an era of incessant human growth tail risks are becoming more likely; our civilisation is more interconnected than ever and we are disturbing the natural world at vast scale. Disease spreads through the paths we have burnt into the world. Extreme weather events increase. Terms like “one in a hundred year event” will become essentially meaningless. And yet more extreme events are still possible. We would be fools if we thought we could never encounter a pandemic worse than this one or that there is no chance that a warming atmosphere could exceed predictions. 

That may be a troubling perspective but should not leave us paralysed in hopeless inaction. These understandings mandate urgent action at large scale ; the hope arises from thoughtful activism. Critics of the precautionary principle often say that identifying these difficult to quantify extreme events is just fearmongering. That view usually arises out of the wishful thinking of wanting to live in an old world that is some shade of normal instead of trying to create hope for the new one. It’s important to define which distribution you are in. Where risks are circumscribed and easier to define – say heart attacks or car accidents – then, yes, standard analyses can be applied. But the type of risks we talk about here are neither bounded nor easy to measure. We share them as a society, and as a world. No aspect of that is amenable to standard cost-benefit because the costs can be unimaginable. 

For the pandemic, that cost in lives lost should be clear looking around the world. For those that still wish to pursue only an economic argument then the cost to the world is estimated to be US $11 trillion by the end of 2021. Estimates of costs of investing in prevention and preparedness for pandemics are an order of magnitude less than that. Even once the pandemic had become inevitable, countries such as ours that employed the precautionary principle with faster and more stringent lockdowns fared better economically. Nor is the intention of the precautionary principle to paralyse a society forever. When we see a large obstacle in the road ahead we better brake rather than assume it is nothing. But that doesn’t prevent us moving forward again. We now have more knowledge, vaccines and evidence of the effectiveness of other interventions such as masks to help us proceed with caution. 

There is one more thing to consider. One type of heavy tailed distribution, the Pareto, describes the distribution of wealth, and privilege, in our world. A small number of people have vast amounts of wealth while large numbers have relatively little. Billionaires might carve through our stratosphere pluming burning dollars behind their rockets but on the earth below whole countries in Africa still wait to be vaccinated. The death toll has reached one in 500 people in the US as a whole, but disproportionately affects Indigenous North Americans. While we try to row back to the centre, we have left whole communities to drown at the edge. If left unaddressed this skewed distribution will push us further towards ruin. 

Our futures are hard to predict. When she was six, as often happens, my daughter’s thoughts turned to the question of mortality. She once told me that she had stayed up at night fretting and counting on her fingers, until she reassured herself I would live until I was 200. I just smiled and said “Not quite that long perhaps, but long enough for you.” Long enough. Our time here is unknown until it is used up. In lockdown my thoughts have turned to how, even when we are overwhelmed facing storm clouds that seem to fill the entire sky, we might still find quiet comfort in the existence of the ordinary around us. The conglomerate of all our interconnected ordinary lives, when lived with a sense of social purpose and the values that seek to protect our fellow beings from further harm, can lead to events that are quite extraordinary in how they turn the world to something new, something hopeful. 

So I’m fine with them, with these fragments of the ordinary among the extreme. With walking round the lounge picking up the multitude of tiny white paper butterflies my son holepunches into existence, then scattering them like ashes into the garden. Or wondering at the residue of sticky dust on my fingers from fishing out a forgotten Lego brick from underneath the couch. And when I am done sweeping the leaves off the deck and the wind picks up and the clouds roll into the far distance, I make my way back into the house, because I guess that bad weather may be on its way. 

Alex Kazemi is a doctor and writer, currently studying Public Health at the University of Auckland. He has worked as an intensive care specialist and was formerly Clinical Head of Intensive Care at Middlemore Hospital, Auckland. He is also an avid day-dreamer.