The trouble with Petropolis [1/2]
I first read the work of Herbert Girardet in Undercurrents in the early eighties, and his short book Creating Sustainable Cities – published in 2006 by Green Books – was fundamental in shaping my view of the planet’s urban boom. This was the book where he calculated that London’s ecological fooprint was 125 times larger than the city itself, and so larger than the UK. So when I found that he was talking at the LSE as a guest of the LSE Cities programme, I made sure I could go along.
The story he told, based on his book, Creating Regenerative Cities, published last October, is that we are on the cusp of a transition to the third age of the city – or at least we’d better be, if we are going to avert the worst effects of climate change. The first age he called Agropolis; the second Petropolis, and the third, Ecopolis. In this post, I’m going to talk about the first two; in the next post, I’ll look at Ecopolis.
It is almost impossible to over-estimate how quickly the city has grown. Until 18th century cities were an add-on to agricultural society, and in 1800, there was only one city of one million people – London. Now the urban population increases by about a million people a day; 50% of the world’s population, or 3.6 billion people, live incities and it is projected to climb to 6.4 billion by 2050.
The Agropolis was a city of 10-20,000 people, sometimes walled, surrounded by successive rings of market gardens, forest, cultivation, then fallow and pasture. These provided food and fuel. The city returned nutrients to this land through its “night soil.” Windpower was an important source of energy. The image, a map of 16th century Aachen, gives a sense of how such towns connected to their surroundings.
A tiny proportion of the population lived in these “cities.” The need for resources effectively limited the size of the city; the Agropolis is a pre-industrial model.
The Petropolis is the modern city, and emerged largely during the 19th century. It is, in Girardet’s words, “utterly dependent on fossil fuel inputs for services of all kinds”, from food systems to sewage. And what those fossil fuels did was to allow the city to scale. During the course of the 20th century, the global population increased four-fold, while urban population increased fifteen-fold.
And this shift has, historically, also increased resource consumption. When a villager moves to a cities, their resource use increases by a factor of four. There’s also a huge imbalance between land use and resource use: cities take 3-4% of world’s land surface and 80% of its resources.
One of the effects of the huge growth of the city during the 20th century in particular is that we end up focusing on the city, rather than the systems that support them. Cities themselves act as if they have “declared independence from nature.” But, of course, they are locked into the same eco-systems as everyone else. Girardet showed us the sums that led him to conclude that London’s footprint was 125 times larger than its surface area, and then said that others, sceptical of his sums, had concluded that he’d under-estimated the impact rather than over-estimated it, missing out from his calculations elements such as petfood, fish and restaurant consumption.
Whatever the figure, it makes you realise how dependent the city is – at almost any scale – on trade, I realised, listening to the presentation, that the boom in urbanisation in the last thirty years would probably not have happened without the revolution in containerisation happening first. In turn, it’s also striking that both of the great waves of globalisation, in the late 19th and late 20th centuries, have gone hand in hand with urban booms.
So, the modern city is built on huge flows of food, energy and waste. Girardet described this as an “urban metabolism,” which extends across the planet sucking in inputs through pipes and cables, along with key metabolic infrastructure such as power stations, reservoirs and container ports. Energy is a critical issue: in terms of per capita energy consumption, every European has the equivalent of 60 energy slaves, every American 110 (assuming a strong man working 10 hours a day, 6 days a week).
It follows that a critical decision in the expansion of the city, even to a population of a million, is how it manages these flows. In London, of course, a defining moment was the “Great Stink” of 1858, when the Thames was overloaded with the city’s sewage, and the city invested heavily in Bazalgette’s sewage network to solve the problem. (There’s a related story here that Girardet didn’t tell: one of the factors that caused the city’s 19th century cholera epidemics was that the city got too big for the nightsoilmen to transport the wastes to the city limits, so it got dumped in cellars and gardens instead.)
The Great Smog
It similarly just exported its problems 100 years later, when coal pollution threatened to overwhelm the city in the 1950s. The Great Smog of 1952 galvanised the authorities, and the 1956 Clean Air Act eventually moved electricity production to power stations outside of London, whose tall chimneys ensured that London’s pollution was instead carried into the North Sea, and to Scandinavia.
And not just London, of course. During questions, there was a discussion about the water shortages that Rio and Sao Paolo are currently experiencing, which can be traced back directly to the clearing of Amazon rainforest to create farmland to feed cities somewhere else. And in the meantime, Rio is directly polluting the water on its seafront. It doesn’t have to be this way: New York City has paid to re-forest the Catskills to maintain the integrity of its water supply.
In the next post, I’ll look at the Ecopolis model of the city, and how that reorganises urban flows to make them more local, and more manageable.