Last week I was in Sao Paolo, Brazil for that city’s Innovation Week. As a New Yorker I thought I was used to big metropolitan areas but Sao Paolo is something else. A vast mix of beauty, power, poverty and everything in-between (like so many cities including NYC). And like so many other cities, Sao Paolo raises an ancient question.

Why do we do this? Why do we build and live in these insane, dense, noisy conglomerations of humanity?

These days, with climate change breathing down our necks, that question takes on an entirely different vibe. Because we are pushing Earth into new territory, we must understand if cities are our planetary salvation or a planetary infestation. Can they help us make the transition to a sustainable version of human civilization or are they the reason we’re facing this crisis to begin with?

There are lots of ways to answer this question: policy, politics, population etc.  But for me there is a different perspective that shifts the emphasis entirely. What happens if we look at the history of life in the context of the history of the planet as a whole?

By looking at the history of life and the planet together we see how biotic activity can change its own planetary environment.  The early forms of Earth’s life were anaerobic bacteria, creatures that could not survive in an oxygen rich environment. But through their own activity that is exactly what was created. They invented a new form of photosynthesis that dumped oxygen into what had been an oxygen-free atmosphere. But all that O₂ was, for them, a poison. The new oxygenated atmosphere forced them, literally, off the Earth’s surface.  From these microbe’s perspective, their own population growth might have appeared to be an infestation – i.e. they were overrunning the planet in numbers or quantities large enough to be harmful and threatening.

Which brings us around to cities.  Some time around six thousand years ago (give or take a few) we began organizing ourselves into a city building species.  The agricultural revolution five or six thousand years before had made surpluses possible. Cities were the cultural revolution that made effective use of those surpluses.  Since then cities have been the engine of our greatest achievements, the cauldron of our most fecund imaginations and test beds for our most daring innovations.  Without cities the progress we have made in terms of an almost infinite increase in the scale of our vision could not have occurred. 

Of course, the steady but relentless push into cities was wildly accelerated with the birth of industry and our subsequent discovery of fossil fuels.  Now urban complexes are ringing our continents, as the overwhelming majority of human beings become city dwellers.

So what’s the problem?  Well, it can be stated pretty simply.  There are lots of lines of evidence telling us that the current system of cities and their supply-chains are unsustainable.  Climate change and the stresses it its likely to exert on our economies is the most obvious example of the back reaction.  But does that mean cities themselves are the problem and we should all move back to the farm? I don’t think so even if that were possible.

Instead, it means is we have to rethink how cities work. This is where it gets exciting.  There is urban agriculture and rooftop farms, there are proposals to make buildings more like plants so that they can get everything they need from where they sit, there are new opportunities to make urban energy use hyper-efficient.  In a thousand, thousand ways some big and some small there are opportunities to reimagine how cities work and how we work within them. 

That is pretty awesome.

With seven billion people and counting it is likely that the density and efficiencies that cities make possible might be our only hope for a vibrant high tech sustainable civilization.  And with 70% of the world’s population scheduled to move into cities by 2050, do we really have any choice?

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PS If you have specific questions or issues you want me to address leave a comment on the website or email me at [email protected]

PPS I could not get this proof-read so please excuse typos etc.

— Adam Frank 🚀