There are many more of us.
In my lifetime the population of the United States has more than doubled. Over these six decades, the population of the world has grown from a bit less than 3 billion to more than 7 billion.
Growth rates are slowing in many places, even reversing in some affluent corners. But our historical experience does not avail us many analogies well-suited to the present context.
US Census Bureau Image
We are more densely concentrated than ever before.
In 1870 one out of four Americans lived in urban areas. By 1920 the urban-to-non-urban ratio was 1-to-1. In 2010 four out of five Americans lived in urban areas. Today about 75 percent of Americans are concentrated on about three percent of the nation’s territory.
Demographers believe that — for the first time — since 2008 a majority of humans live in cities. This is a profound transition, but so suddenly achieved the full implications of our new condition cannot be confidently claimed.
For most of human history the vast majority of people have produced their own food or lived very close to where their food and other consumables were produced. The systems on which modern urban concentration depend have mostly emerged in the last four generations. They continue to emerge.
Whether this is a brave new world or one blithely unaware can be debated. In any case, never before have so many depended on so few so very far away.
For at least 5000 years humans have gathered in cities. To live in cities was to be civilized. Athens at its classical peak housed about 140,000 (about 30 percent slaves). In the Third Century Rome exceeded one million inhabitants, the greatest concentration of humans until 18th Century Beijing (when Rome had collapsed to about 100,000).
Only in the last century has technology allowed the vast majority of us to detach ourselves from the task of feeding ourselves and selling the excess of our crop to others. For most of human history there has not been sufficient excess to support anything like contemporary density.
Map by William Rankin from Census data
To supply these dense concentrations we increasingly specialize.
The map above (click on image for more detail) suggests the kind of crop monocultures that have emerged to supply the intense demand of our cities. Similar maps can be displayed for other monocultures: pork, chickens, pharmaceuticals, aircraft, micro-chips, financial services and more. All of which makes sense in terms of rapid exchange of information, availability of expertise, and services for processing, packaging, transport, and such.
High volume, concentrated sources of demand and supply, and specialized production and processing tend to be very efficient… most of the time.
The same efficient networks are just as adept at spreading contamination and disruption. The networks in effect becoming fat targets — much fatter than previously — for hurricanes, earthquakes, drought, pandemic and even just stupid mistakes.
Peter Drucker wrote, demography “is the future that has already happened.”