Can Cities Feed Their Inhabitants?

There are three dominant trends to which cities and national governments must respond in order to secure food supplies for their people. First, between 1980 and 2011 the not dependent on agriculture doubled to 4.4 billion, and, according to the Food and Agriculture Organization this population is growing at a rate about five times that of the agriculturally dependent population.

Second, the amount of agricultural land available for growing food is declining and will soon start to be adversely affected by climate change. Third, in 2011 agricultural subsidies in the world’s top 21 food-producing countries totalled an estimated US$486bn. At the same time, agriculture and livestock remain a major source of greenhouse gas emissions – 4.7 billion tonnes of carbon dioxide-equivalent in 2010 (the most recent year for which data is available), an increase of 13% over 1990. While efforts are ongoing to reduce emissions from energy production and transport, food consumption is being ignored. The obvious point is that agricultural subsidies need to be redirected from unsustainable practices to sustainable ones.

The growing of food in cities won’t mean that conventional agriculture will disappear. We might be able to keep chickens and produce eggs in urban environments but, at present, we cannot grow staple foods, such as grain, indoors or at a small scale. It seems that in any case our consumption of meat protein is going to have to decline considerably both because of the greenhouse gas emissions associated with meat production and because it is an inefficient use of land. Or perhaps we will find a way to grow meat-like protein in factories without the need for animals, as in the case of the Quorn mycoprotein.

For the remainder of our diet we are going to choose from a range of options: allotments, rooftop growing, growing on the vertical walls of buildings, and growing indoors with hydroponics, aquaponics and/or aquaculture. All of these are being practiced now, and if supported by a switch of agricultural subsidies can produce perhaps as much as 30% of the city-dwellers’ nutritional requirements. In many cases, they do not even need support. Add to mix the use of hinterlands around cities, as used to be the case (for example, Paris was able to feed itself in the 19th century from its hinterlands), and urban food production could provide multiple benefits, including: a drastic reduction in the carbon footprint associated with food miles; a reduction in food lost due to crop failure; an improvement in health and fitness when people participate in growing and have a better diet; a big reduction in water pollution due to nutrient recycling; and much greater water efficiency due to water recycling.

The corporate option
I am convinced that the vast majority of local food will come from giant warehouse-type buildings because growing crops outdoors, whether in vacant lots or on rooftops, without the use of poly-tunnels or greenhouses, leaves the growers vulnerable to the vagaries of the weather and the strictures of the seasons. On the other hand, in a controlled environment you can have several growing cycles during a year, and root vegetables can be continually harvested if grown in a soil-less environment where there is no need to dig up and kill the plant.

So, I foresee that there will be one or more of these giant sheds (with or without glazing) in every city, owned by the likes of Amazon, or perhaps in the form of  franchises like McDonald’s, Starbucks or Costa. They may include in their portfolios high street cafés, hotels and restaurants where you can pick your tomatoes and greens and eat them fresh because they are grown in the same building.

In these warehouses there will be tiers of rack after rack of vegetables being grown in precisely controlled conditions. Amazon already has the technology to monitor what is happening in remote, upper corners of its climate-controlled warehouses and to bring products down on demand for shipping. From a consumer point of view, you will be able to order your vegetables using an app, and they will be harvested and delivered to your door within hours: fresh, local and organic.

These warehouses will be fine-tuned to minimize energy use, to produce the maximum amount of nutrition and to produce for the minimum amount of inputs. They will be far more efficient than what happens in an open field. Some might find this a horrifying prospect, but the choice is stark: either this or starvation for many of the 10 billion people who will walk the earth in 2050 and beyond.

The technology to produce and operate these warehouses is already here. They are on the cusp of being commercially viable. A marketing push will be required to persuade people to buy the products – or perhaps they won’t care where their food comes from.

Small-scale options
Farmed Here and Green Spirit, based in the state of Michigan in the United States of America, are two examples of pioneering urban-growing enterprises that support the local community, source everything locally and train unemployed teenagers. In Detroit, Farmed Here runs a profitable indoor vertical farm, the first and only US Department of Agriculture Organic Certified and HACCP-certified and audited aquaponic vertical farm in the US. Farmed Here’s head of development, Paul Hardej, says that it has a greater than 95% success rate with plants, compared with 70% on traditional farms.

Green Spirit Farms near New Buffalo, targets under-used urban space to create its vertical farms and has designed a system that is simple to operate and harvest. It has a stacked indoor growing area that yields 12 harvests per year, compared to around seven harvests per year in California where many of the country’s fresh vegetables are grown.

City administration
City administrations will need to change. At present, there are no widely used standards, no building codes and no proper regulations that allow city authorities to issue permits to developers who want to grow food or raise chickens or fish in cities. Right now, it’s problematic to get permission. For example, in Chicago, Paul Hardej had to construct an undercover test farm as a pilot to develop his technology before he could persuade the city’s mayor that his idea worked.

Research and development
In the United Kingdom, three entities are working together to validate work on plant responses, measuring the number of grams per mole of nutrients and working out how they can scale up. The three are: CambridgeHOK, a leading producer of retail structures, commercial glasshouses and associated equipment; Stockbridge Technology Centre, a centre of excellence supported by both the production and supply sectors of the horticultural industry; and the multinational Phillips Lighting company. Tim Haworth of CambridgeHOK says that the economic models “need to be worked out, factoring in how the model is affected by local situations, outside climate and expected prices. Automated processes also need to be refined to cut labour costs further and use space to maximize the productivity per cubic metre”.

The Netherlands already boasts many experts in the required technology. Jan Westra, a strategic business developer for Priva, a multinational that manufactures control technology for indoor growing, travels the world looking for business opportunities. “We can completely control indoor climates. In Holland, we use underground heat storage to moderate internal temperatures, storing solar heat in the summer and releasing it in the winter. It’s very efficient. We also control light levels and humidity.”

A rooftop growing experiment in Paris is testing the results of using different substrates made from urban organic waste. Given a choice of compost, vermiculture, coffee grounds with mycelium and compost or crushed wood, different root and leaf vegetables will thrive on different substrates. The same researchers from France’s Institut national de la recherche agronomique have tested leaves of plants grown in cities for lead concentration and fortunately found them to be well below the danger threshold.

Community initiatives
Community growing brings communities together, generates links and makes people happy, but not everybody wants to do it. For many people, growing their own food is a drag, but when people actively participate in sourcing their own food, it galvanizes individuals, creates new respect for nature, and reconnects urbanized humanity to the soil with which it was once intimately familiar. For these reasons, community growing initiatives are vital in whatever form they take.

Cities that adopt these practices will thrive and achieve greater food security. The pioneering cities may even be able to export their expertise. Every area will find their own patchwork of solutions.



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