Why “Smart Cities” Wont Stop Global Warning – And May Even Accelerate It

Those of us who like to think about city-scale innovation also like to think that it is somehow going to lead us away from our carbon-abusing ways towards a new world of sustainability.

Well I’ve got some bad news: it’s not. Sorry to say it.

Civic innovation and “smart city” technology is going to do a lot to make cities more usable. But it isn’t going to help us solve the global warming conundrum. In fact it may even make it worse, accelerate the problem.

That’s right – all of those apps, all of that open data, all of those super-cool realtime traffic alerts, all of the things that make the system work better – they may actually making carbon output worse.


There’s a little-known idea called the Khazzoom-Brookes Postulate (that name probably explains why it is so little-known), that explains it like this: increasing efficiency in any macro system has the unexpected effect of also increasing demand in that system over time. Basically, making a system more efficient makes resources in that system cheaper, which in turn makes using those very resources more economical and attractive to others, who then end up using more resources than they did before.

When things get more efficient, they get cheaper to everyone. And when things get cheaper, people respond by consuming more of those things than they did when the cost was higher. You end up back where you started, or worse. It’s a boomerang effect.

Let’s take a real-world example:

Say you build and launch an app that makes it easier for people to carpool. And say it actually works, and 10,000 people stop driving and instead share rides with others to work as a result. You’ve made the commute system more efficient – less energy spent to get people to work in the morning. Carbon output goes down. Great.

But a secondary effect of taking 10,000 people off the road is to create more space on the freeway during commute hours. The “cost” of driving, in terms of time, goes down for other people and businesses. That incentivizes them to fill up that space themselves. Even if they didn’t plan on using that space originally, they now think about using it – it’s a resource that was formerly expensive and is now suddenly very cheap. Some may decide to switch from taking the subway to driving, because it’s suddenly so easy to drive (extra space!). Others may be businesses who decide to open a new delivery route and make more money, because the lighter traffic presents an opportunity for them.

When all is said and done, according to Khazzoom-Brookes, you may very well have more than 10,000 people replacing the 10,000 free spots on the freeway created by the app. Your app to get fewer people driving has led to more people driving.

This goes on across every vertical, in every nook and cranny that you may be trying to improve. Making the system more efficient encourages people to use more resources, which pushes use of the system even higher.

This may be why, despite the fact that our cities are quickly getting smarter and more efficient than ever, 2010 saw the biggest single-year increase in global carbon output in history, what one scientist called a “monster” increase in emission.

None of this is an argument against making cities more efficient. Cities need to become more efficient, absolutely. But it is to say: efficiency is good for a lot of things, but it isn’t good for reducing carbon output.

What is good for reducing carbon output? Three things: legislation, behavior change, or clean energies. Or a combination of all three.

Maybe these things should be considered as part of a broader “Smart City” strategy as well, if we want cities to really be Smart?

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Daniel Helfrich

I think I could agree about the name of the postulate, Khazzoom-Brookes, that it might be discouraging a wider awareness of itself. Nice writeup. Very disturbing to this altruistic Honda Civic Hybrid driver who hypermiles, and who’s thinking forward to acquisition of an all-electric car for my commuting…