Can Urban Agriculture Feed the World's Growing Cities?

Living in a city puts everything at your fingertips: From fashion and movies to social movements and political experiments, residents of urban areas experience most everything before it trickles through the suburbs and into rural communities. The same can’t be said for food; even the most devoted locavore depends on produce that flows up the cultural stream, making its way from the countryside back to the urban core. But as more of those rural residents follow that food, making new lives in urban communities, should vegetables, like film premieres, emanate from cities too?

There are more people living in cities now than ever, and population growth is expected to center on urban areas. According to the United Nations, by 2030 nearly 5 billion people will be living in cities, much of them in Africa and Asia. This historic shift in population crossed a threshold in 2008, when more than half of the world’s people were living in cities for the first time.

The combination of rising density and reduced rural populations is changing the ways people get their food. Today an estimated 2.6 billion people—40 percent of the global population—are small farmers, raising crops for personal consumption on fewer than five acres of land, according to Greenpeace. In Africa, nearly 90 percent of harvests come from small farms. With many of those farmers expected to head to city life in the coming years, urban agriculture has been touted as a potential way to feed the larger, more dense population of the future. But just how much food could be grown in the world’s cities? How much urban area would have to be dedicated to growing crops in order for cities to feed themselves? A first-of-its-kind study published last month in the journal Environmental Research Letters attempts to answer those questions.

A team of geographers from Montreal’s McGill University compared the total amount of urban area available (excluding large urban open spaces like New York’s Central Park), the production of 27 vegetable crops, and both the total and the urban population of 165 countries. In short, the study finds that roughly a third of the world’s urban space would need to be planted with vegetables to meet the global demand of city dwellers.

So, it's possible for urban farms to feed the surge in urban dwellers that is being anticipated by population shifts.

But as the authors note, urban agriculture “is local by nature,” and a consideration of it on a global scale is “bound to include generalizations that are justified and simplifications that can be misleading.” Even on a country-by-country analysis, which is still a grand amalgam of backyard and rooftop gardens, it’s clear that meeting urban demand with a local, urban supply is both more nuanced and more complicated. The study doesn't address the labor part of the equation either; farmers aren't moving to cities to continue farming.

When considered in terms of current demand—the amount of vegetables people are eating—the prospects of urban agriculture seem bright: There are 22 countries that could supply their cities by farming less than 10 percent of urban land. Furthermore, 39 percent of the global population lives in countries that could feed urban populations by farming less than a quarter of city land.

There’s quite a gulf, however, between the amount of vegetables people eat and how much they should be consuming in a healthy diet—and that’s where the prospects for urban agriculture start to look decidedly less utopian. Only nine countries could feed their cities with less than 10 percent of urban land, and 51 countries couldn’t meet a recommended daily serving of 300 grams of vegetables even if they devoted all of their cities to growing food.

When looked at in terms of a healthy diet, the countries that meet urban demand by farming less than 25 percent of their cities are mainly clustered in Europe and North America; according to this study, the developing world largely cannot make such a local, sustainable food supply work—despite urban agriculture being quite commonplace in many countries. High population density and less available urban space makes it a difficult equation. The authors note that of the 29 “lowest food security” countries, 23 would need to farm more than 100 percent of their urban land to feed city dwellers, and 12 would need more than 200 percent to be devoted to agriculture.

That’s not to say that urban agriculture can’t be part of a sustainable future for the world’s growing population of city dwellers. Rather than focusing on metropolises like New York City, the study’s authors say that developing urban agriculture in midsize cities, where population density is lower and more space is available for crops, is the key to self-sustaining communities.