We are living in a uniquely urban time in Earth’s history. In 1800, and for a thousand years before, just 2% of the world’s people lived in urban areas. Within the past five years, we have reached the point where more people are living in cities than in rural areas. By 2050, around three-quarters of the estimated 10 billion people on Earth will live in cities. It’s by far the biggest migration in human history, and it’s well underway.
So much so that the Anthropocene will be dominated by one species: Homo urbanus.
As a result, most of our species will live in artificial environments. The evolution of urban landscapes will be one of the strongest environmental changes to affect us.
Civilisation, that great loaded descriptor of human society, originates with cities. They have grown from the once vast Nineveh – home to 120,000 people in the ancient Assyrian Empire in 650 BC – to the Anthropocene’s megacities, defined as having more than 10 million inhabitants. There are currently almost 30 megacities on the planet (there were just three in 1975) – with the Tokyo metropolis, Japan’s national capital region, hosting over 35 million people at a population density more than double that of Bangladesh. By 2050, these megacities are expected to merge into dozens of megaregions, like Hong Kong-Shenhzen-Guangzhou in China, with more than 100 million people living in an endless city skyline.
The denser the city, the more productive, efficient and powerful it becomes. The theoretical physicists, Luis Bettencourt and Geoffrey West calculated that if the population of a city is doubled, average wages go up by 15%, as do other measures of productivity, like patents per capita. Economic output of a city of 10 million people will be 15-20% higher than that of two cities of 5 million people. Incomes are on average five times higher in urbanised countries with a largely rural population. And at the same time, resource use and carbon emissions plummet by 15% for every doubling in density, because of more efficient use of infrastructure and better use of public transportation.
The urban revolution of the Anthropocene could prove to be the solution to many of our environmental and social problems, allowing humans to inhabit the planet in vast numbers, but in the most sustainable way. Or, it could finally prove to be our species’ undoing, the apocalyptic version of the dystopian megacity so often portrayed in science fiction.
Whether the cities of the Anthropocene will be environmentally sustainable or not depends on how the slum districts of developing world cities evolve. Will cities follow the inefficient North American model: suburban sprawl of highway-linked satellite towns, or rather the closely packed high-rises of Hong Kong and Singapore? Seoul is one example of how a city can transform in a couple of decades – from a filthy slum in which one-third lived in low-rise squatter settlements, to a shining functioning city of metro-linked skyscrapers in which most of the 25 million population live in healthy surroundings.
Apart from a few examples, most cities were never designed or planned, they grew - sometimes over thousands of years – in an ad hoc pattern. Occasionally, sections would be entirely rebuilt according to architects’ plans, but these opportunities were usually the result of disasters, such as earthquakes or bombings, or because of grand schemes, such as slum clearance, industrial development or large-scale municipal constructions, such as a new highway or transport system.
Now architects are having to re-think the city in the age of high population, strained resource use and global environmental impacts. In some places, such as Tianjin in China, planners are designing entirely new cities for the Anthropocene, trying to avoid errors of the past and achieve a sustainable solution from the outset.