So there was an opinion article in the Times the other day by Dickson Despommier, professor of public health at Columbia, who is writing a book on urban farms and has a company to consult on urban farms, pushing urban farms. I came across the same idea (from the same source) a few years before referenced in How the World Works and still remember it, because it seemed to me at the time to be one of the more breathtakingly naive concepts I had ever come across. In summary (I won’t try to be fair, you can read the article yourself or go to www.verticalfarm.com) it is, wouldn’t it be great if farming was done in skyscrapers?
Back then, I wrote in response:
I don’t know if this is a worse idea from the theoretical or practical perspective. Let’s see:
Theoretical: I am an environmentalist, but it drives me crazy to see ostensibly smart and credentialed environmentalists focus so hard on one variable - in this case, land - while ignoring all the others. Sky farming would save on land and transport - at the cost of vastly increased energy and infrastructure costs. Are we really going to save the earth by replacing the sun with millions of grow lamps?
Practical: This proposal bends over backwards to optimize cheap inputs in favor of expensive inputs. Replace farm land with high rise construction, the sun with electrical energy, and throw in exceptionally complicated technological control and management. “Green” skyscrapers with integrated solar panels, cogeneration systems, black water reclaiming etc. are REALLY expensive. The idea of building an advanced green skyscraper in the middle of a city for the purpose of growing food is economically absurd. Not financially difficult as a result of weird pricing forces, like solar and wind power, green building, or other sensible things, but fundamentally economically absurd.
To solve the population/land production mismatch, why not just apply some of the professor’s strategies to farmland already in use to make it more productive and sustainable? Build more greenhouses, collect and recycle agricultural waste and runoff, reduce pesticides and non-organic fertilizers when you can? You can do all these things without building a skyscraper on the most expensive land you can find, for pete’s sake.
(How lucky for me that I always seem to come across the urban farming idea on slow work days…)
Since then the proposal seems to have taken some steps towards reality. Instead of new green skyscrapers, the proposal is now for a five story building on an eighth of a block, and it’s now called “urban farming” instead of “sky farming.”We’re getting closer to a concept known as “gardening” which I think makes a lot of sense.
But Despommier still claims that “the real money would flow once entrepreneurs and clean-tech investors realize how much profit there is to be made in urban farming.” This is highly nuts and doesn’t pass a first level in-your-head economic analysis. You can use the numbers the author provides in his op-ed: let’s start with land.
Production in an urban farm, he says, is 10 to 20 times a normal dirt farm. This would mean (I think) that the five story farm he proposes would produce as much as 100 acres of farmland. OK, this gets you close to parity in terms of urban land cost - although certainly not in Manhattan. But you’ve still got to build a building, and a building with intensive lighting, water, energy, waste removal etc. requirements (because, you know, you still have to artificially provide all the stuff you get for free when you grow plants in the ground outdoors - see where I’m going with this?) - perhaps comparable to a light industrial food processing plant. Despommier says he thinks he can build his five story prototype for $30 million. That would be a development cost of about $300 per square foot, in Manhattan, which means one of us is missing something. But even if he’s right, this is only the capital costs - we have not touched energy, maintenance, labor, or any of the other ongoing costs that are necessary to sustain such productivity. The thing does not look even close to covering costs to me - or to put it another way, since he spends a lot of time on how we are losing a lot of productive farmland, food costs would have to go to places none of us want to see for this to make any kind of sense.
I am not against urban farms. There are undoubtedly places in any big city where an urban farm would be great, and areas of the world in which intensive industrial agriculture could have a lot of advantages. I am also not against thinking outside the box, re-imagining how our society should work and our cities should look, and in general trying to avert the general catastrophe that global warming might be. What makes me spend way too much time writing about this is that this guy has spent a lot of his and his students’ time, and has gotten a lot of press and a certain amount of support, all on the basis of how great it would be, without ever having taken it to the logical next step of does it make sense? He addresses lots of details, but he seems to have never tried to put the thing together even in a rough way. I find this kind of loose thinking extremely annoying.
“When people ask me why the world still does not have a single vertical farm, I just raise my eyebrows and shrug my shoulders.” Well, yes. Exactly.