AFTER overdosing on chaos, science’s big thinkers seem determined to put the genie back in the bottle. Now they are finding unexpected order everywhere, from the cosmos to cellular biology to the whiz-bang complexity of human society. How much it helps us negotiate the miasma of cause and effect in the real world is moot, but Geoffrey West makes a heroic effort to do just that in Scale.
A British-born particle physicist, West came to public attention a couple of decades ago when he introduced power laws to biology. He showed how, despite hundreds of millions of years of evolution that ought to have maximised complexity, all life seemed spookily similar. The “most complex and diverse phenomenon in the universe” obeyed a series of simple rules predictable from network theory.
Draw a graph plotting the metabolic rate of any animal against its body mass, and everything from a mouse to an elephant falls neatly on a straight line. The bigger the body, the slower the metabolism. Even odder, whatever their weight and however long their typical lifespan, every mammal can expect to expire after the same number of heartbeats (about 1.5 billion, if you’re counting).
Clever. So what next? Cities, obviously: the hearts and minds of our modern industrial world, they are even more complex than life forms.
West hit the headlines again when he argued that cities, too, operate according to predictable power laws. They are very like organisms, except they don’t die. They don’t even mature; they keep on growing – like a cancer, in fact.
“West argues that cities, too, operate according to power laws. They are like organisms, but don’t die”
And while in the natural world, it is small creatures that live in the fast lane, metabolically speaking, in cities the opposite is true. Urban metabolic rates, as it were, increase with size, taking humanity with them (Homo urbanus… maybe that makes us the cancer). The bigger a city gets, the more its inhabitants get up to: busier bees in a bigger hive. Per capita, they generate more GDP, commit more crimes, patent more innovations and spread more disease. People even walk faster in big cities. Big is bountiful, beastly and above all rapid.
West grew up in rural Somerset, the son of a dress-maker and a professional gambler. Excelling in mathematics, he made his way eventually to the Los Alamos National Laboratory, New Mexico. His startling discoveries followed a mid-career move to the nearby Santa Fe Institute, an interdisciplinary think tank in a very small city whose intellectual productivity rather belies West’s urban power law.
The first part of this book is a brilliant exposition of those intellectual forays into biology and urban metabolisms. The second part digs in deeper, by asking what all this surprising order amid complexity means for humanity and the planet in the Anthropocene. Do West’s scale laws doom us, or might there be a path to a “sustainable future”?
Here, I think, he begins to come unstuck by putting his own power-law spin on some rather old-fashioned neo-Malthusian catastrophism – the stark prediction of mass starvation as the world’s propensity to over-breed outpaces food production.
In the late 18th century, the Victorian country vicar Robert Malthus had defined our demographic predicament by saying that human numbers rise exponentially (2, 4, 8, 16…) over generations, while the resources available to feed us can only rise arithmetically (2, 3, 4, 5…), however hard we try. “The power of population,” Malthus concluded, “is infinitely greater than the power in the Earth to produce subsistence for man.”
It is worse than that, says West. Our post-industrial urban world zooms ahead not exponentially, but “super-exponentially”. The metabolism of a human body requires an input in food calories at a rate equivalent to about 90 watts, whereas the lifestyle of the average American requires a staggering 11,000 watts.
Delivering this largesse while sustaining a world population approaching 10 times that in Malthus’s day has only been possible because of something Malthus never factored in: technological advance. Whether steam power or the green revolution in agriculture or digital information technology, it has transformed Earth’s capacity to sustain us. So far, so lucky.
But because we are pushing the bounds of the planet’s resources with faster-than-exponential growth, we have to come up with new transformative technologies ever more quickly, says West. “Not only does the pace of life inevitably quicken, but we must innovate at a faster and faster rate.” We are not, he says, just on a treadmill; we have to keep jumping off one treadmill on to an even faster one. This can’t go on.
I headed breathlessly for the final pages – reading ever faster, as seemed appropriate – to see how he would resolve the cliffhanger. The final chapter offers the “vision of a grand unified theory of sustainability”. It asks the right question: “Can we return to an analog of a more ‘ecological’ phase from which we evolved… a no-growth, stable configuration?” In other words, can cities, as the great centres of “exponential innovation”, deliver the eco-sustainability changes that are our only way out? Can cities become not the problem but the solution?
What is a shame is that he only asks this question on the last page of the last chapter. And answer there is none. Instead, this otherwise eye-opening book peters out in a way very unlike the world he envisages. Let me suggest one denouement. I think the missing element is already with us, hiding in plain sight: demography.
West lists population growth as central to his “successive accelerating cycles”, and takes as a given the future exponential growth that Malthus warned about. But this is wrong. For the population “bomb” was a temporary phase caused by the arrival of transformative medical technologies that, for the first time in human history, allowed most kids to grow up and have kids of their own. World population doubled in a generation, then doubled again.
“We are not just on a treadmill; we have to keep jumping off one treadmill on to an even faster one”
But that exponential phase has passed. People are not following Malthus’s lemming-like demographic model. Instead they are reducing family sizes to reflect the new survival rates. The world fertility rate has halved in half a century to 2.4 children per woman. That is approaching stable replacement levels. We have already reached “peak child”, and peak population will follow.
Even consumption may have its limits. Many Western economies have reached “peak stuff”. We no longer consume more and more basic resources each year. We pollute less, too. Yet nowhere does West acknowledge these decidedly non-exponential megatrends. Why? Because, despite his book’s prescient title, I suspect that he is not looking at them on the right scale. He is using a microscope to peer at the 20th century when what he needs is a pair of binoculars to scan the historical horizons.
In the past, our species has seen long periods of fairly stable population followed by bursts of growth when technologies – whether tool-making, agriculture or industrialisation – transformed the planet’s capacity to support us. This suggests an ability to manage our numbers in ways beyond Malthus’s imagining, or, it appears, West’s. We seem to be returning again to demographic stability today. Could that be our salvation?
Perhaps West is right to argue that industrialisation and urbanisation have changed everything, putting us on a super-exponential trajectory that we cannot hope to escape this side of apocalypse. Or perhaps the defusing of the population bomb and our changing sensibilities about the idea of unending economic growth will alter societies in ways that transcend his power laws. I’d love to know what he thinks. It would have made a fascinating final chapter.
Penguin Random House/Orion
This article appeared in print under the headline “The power of us”
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