Can Urban Agriculture Help Cities Access More Diverse Diets?

James Wong, ethnobotanist and presenter of BBC’s ‘Follow the Food’ series, examines how urban farming could offer sustainable ways for city populations to access high-value, nutritious yet perishable foods like fruits, vegetables and protein.

In the future, there will be more of us than ever, but we won’t all be living in the countryside next to where our food is grown – most of us will be in cities. By 2050, it is estimated that more than 60 per cent of the world’s population will live in a city, and they will all need food. But breakages in food supply chains during the Covid-19 pandemic highlighted the distances our food often travels and the potential for agility in that system.

Is it possible to move food production closer to the area of its consumption?

I grew up in the high-rises of Singapore, and often went on school trips to rooftop gardens growing salad leaves. Even then, I thought it was crazy to think you could feed a metropolis on lettuce. But as we discover in the new series of ‘Follow the Food’ on BBC World News, times are changing.

The world’s largest urban rooftop farm, Nature Urbaine, located on the seventh floor of a building in Paris. Photo credit: Rima Armstrong (BBC)

Overground

We recently visited the world’s largest urban rooftop farm, Nature Urbaine, located on the seventh floor of a building in Paris. At 150,000 square feet – the size of two football pitches – it dwarfs all of those rooftop gardens I saw as a kid.

At Nature Urbaine, they concentrate on growing food such as tomatoes, strawberries, eggplant and butternut squash. When it is in full production, the farmers will be harvesting up to 1,000 kilograms of 35 different varieties of fruits and vegetables every day. But, with only so much rooftop available, urban farmers will need to look elsewhere too.

Underground

Within one of Paris’s 600 hectares of disused car parks beneath the city’s streets, Jean-Noel Gertz co-founded La Caverne, a unique urban farm that grows mushrooms underground. Delivered to local shops and restaurants, the farm has the ability to grow up to 100 kilograms of mushrooms per day, across 38,000 square feet.

With some varieties of mushroom containing almost a third of their dry weight as protein, they could be a fantastic addition to supplement the leafy greens associated with urban farms.

La Caverne, an urban farm that grows mushrooms under the streets of Paris. Photo credit: Rima Armstrong (BBC)

Going underground opens up a whole new dimension to urban farming, but it’s not the only direction we can take to feed our growing population – we can also go underwater.

In the sea 

Ten of the world’s largest megacities are situated on the coast, but only two per cent of our global calories are sourced from the seas. The majority of this comes from fish, but our fish stocks are heavily depleted. One possible solution is to turn to sustainably-farmed shellfish like mussels, but for this to become a realistic food-source grown right next to coastal cities, it would require a big change.

As a source of protein and minerals, mussels tick every box. But they are so mineral-rich because they are filter feeders, sucking in everything in the seawater around them – including heavy metals and other pollutants. Could the waters around coastal megacities ever be clean enough to support this?

New Yorkers think so. Home to 18.8 million people, New York was once known as the oyster capital of the world, but a population boom and pollution all but wiped out these filter feeders in little under 100 years. Today, New York harbour is cleaning up its waters, with a project to see nearly one billion oysters back on its harbour floor by 2035 proving how farming the waters around megacities may be possible in the future.

Vertical farming

With land space at a premium, could vertical farming be the key to urban farming? 80 Acres Farms in Ohio is a big player in the rapidly growing business of vertical farming, aiming to be one of the largest, fully automated farms in the United States, with the capacity to deliver affordable produce on demand.

At 55 feet high, the farm has 10 rows, 10 levels and is 10 positions deep. In just 70,000 square feet, this vertical farm will robotically plant, harvest and package over USD $2 million of nutritious, sustainable and affordable produce annually – something that wasn’t feasible 10 years ago without the latest technology.

80 Acres Farms in Ohio is aiming to be one of the largest, fully automated farms in the United States. Photo credit: Rima Armstrong (BBC)

Fresh ideas

It is easy to dismiss urban farming as a gimmick, a science fiction of the future. But what I have found out through my journey for ‘Follow the Food’ is that to develop practical solutions, you do have to entertain ideas which, on the surface, sound weird and wonderful. With urban agriculture, I think it really is a case of “watch this space”…

To find out more about ‘Follow the Food’ or watch the full series, visit the BBC website, and follow @BBCFuture on Facebook and Twitter for the latest updates.