Dinner for 10 million

After decades of progress, global hunger is rising once more. Even before Covid-19, the world faced a growing food security crisis, and the pandemic has pushed millions more into hunger. In 2019, around a quarter of the world population were experiencing moderate or severe food insecurity; in 2020, this shot up to nearly one in three, or 2.37 billion people. 

Our precarious global food system is both a cause and a victim of global warming, and the situation will become more acute as the climate crisis intensifies. Globally, food production accounts for 37% of greenhouse gas emissions. And as the latest report from the UN’s Intergovernmental Panel on Climate Change warns, some of the impacts are now irreversible: we face a future of more frequent heat waves and droughts, increasingly severe weather events, and greater threats from fire, pests and diseases. This spells trouble for staple crops like corn, maize and wheat, which millions of people around the globe depend on. Without effective adaptation, it is estimated that yields could fall more than 30% by 2050. Hotter, more acidic oceans will wreak havoc on the international fishing industry. A significant loss of plant and animal biodiversity is projected to bring ecosystems to the brink of collapse, and agriculture is largely to blame. 

At the same time, the global population is growing and mass migration from rural areas into cities is putting yet more pressure on supply networks. More than half the world already resides in urban environments; by 2050, they are projected to be home to almost 70% of 9.7 billion people. Those cities will need to eat, and it’s not at all clear how our food system — drawing from a complex web of regional, national and international sources to satisfy consumer appetites — will feed them. 

So how do we fix it? For many, the answer is greater self-sufficiency. Urban agriculture is gaining traction as a way to shorten supply chains, reduce carbon emissions, rebalance ecosystems and put city dwellers back in touch with where their food comes from. It is already responsible for 15-20% of global food production, with significant potential for growth. But it also presents a whole lot of questions, from how we should prioritize different land uses to what kind of urban lifestyles we will lead in a less hospitable future. 

A planetary diet 

Before we determine what a sustainable food system would look like, we first need to ask what exactly we should be eating. Around the world, food has sweeping public health implications. Obesity is estimated to kill nearly 3 million people each year, and is linked to a host of other health problems that will profoundly challenge the viability of healthcare systems in the decades ahead. A study published in The Lancet found that between 1990 and 2017, one in five deaths globally were attributable to poor diets that were high in salt and fat, and low in fruit, vegetables and whole grains.

Perhaps the most comprehensive answer to date is the Planetary Health Diet, developed by the EAT-Lancet Commission, which convened a panel of 37 scientists in various fields to work out how to feed a future population of 10 billion, healthily and sustainably. Rather than a set menu, the result is flexitarian and intended to adapt to any geographic and cultural context. “Essentially, we need to be eating a lot more whole grains, fruits and vegetables, and a lot less ultra-processed foods and animal-based foods,” explains Emily Norford, urban food systems manager at non-profit EAT, which works to catalyze a global food systems transformation. “The whole world doesn’t have to go vegan or even vegetarian, just increase the proportion of plant-based foods that we’re eating and reduce everything else.”

So far, 14 major cities around the world have signed the C40 Good Food Cities Declaration, committing to achieve a Planetary Health Diet for all by 2030, with balanced, nutritious food that reflects the local culture and growing conditions. This includes supporting greater consumption of plant-based foods, reducing food loss and waste by 50%, and aligning food procurement policies to the principles of the diet, ideally sourced from organic agriculture.

For example, officials in Copenhagen have been using its significant purchasing power to drive demand for local and organically produced food: nearly 90% of the meals consumed in its canteens are now organic, and the supply chain offers a far more diverse range as a result. As well as restructuring procurement policies, staff in the municipality’s 900 kitchens were trained to cook from raw rather than processed ingredients and to avoid waste, allowing them to afford more expensive organic foods without any increase in budget.

Localized food production is central to the Planetary Health Diet philosophy — it also calls upon cities to set land aside for urban agriculture and community gardens. “It’s about awareness of where your food comes from and finding ways to prioritize food that’s produced closer to where you’re actually going to consume it,” Norford says. “By focusing on local food, that means you’re also focusing on seasonal food, so what grows best in your geography.”

Cities, not islands

But how self-sufficient could a city ever hope to be? The potential of urban agriculture depends on many factors and varies from one place to the next. A 2018 study estimated that if cities all over the world used vacant land for urban farming, they could produce up to 180 million tonnes of food annually, approximately 10% of global legume and vegetable crop yields. Another recent study found that many cities in the less populous middle and north-west regions of the US could feasibly feed their entire populations with food produced locally — especially if consumers were to eat less meat.

On the other hand, researchers exploring the potential for urban farming in Boston, US, found that all of its vacant land and rooftops could supply only 30% of the city’s fruit and vegetable demand. Many cities, particularly in the northern hemisphere, will be incapable of providing residents with the variety they have come to expect. If you live above the equator and are accustomed to buying pineapples at the nearest grocery store, then eating purely local might feel like taking a step backwards.

Arguably the good news here is that transportation is far from the biggest impediment to building a low-carbon, future-proof food system: what you eat counts for more than where it comes from. Although more than a third of total greenhouse gas emissions are the result of global food production, most of those emissions come from animal agriculture. Experts estimate that if all the cows being raised for food were a single country, it would be the third-highest greenhouse gas emitter in the world. Food animals also require a huge amount of space, with more than 26% of the planet’s land being used for livestock grazing, and 33% of total available crop land currently used for livestock feed production.

Even the most sustainable ways of making animal protein still result in higher greenhouse gas emissions than plant-based sources, according to a 2018 study by researchers at the University of Oxford and Swiss organization Agroscope. This analysed hundreds of life cycle assessments for different food products all over the world, examining the carbon footprint, energy and water use per grams of protein from different animal sources, such as beef, lamb, cheese, pork and eggs, in comparison with plant-based options, such as tofu, beans, peas and nuts. It also looked at the potential for eating more local foods to reduce environmental damage. Another study from 2008 by Carnegie Mellon University compared the relative greenhouse gas impacts of food production versus long-distance transportation, aka the popular concept of “food miles”. It found that what consumers ate and how it was produced accounted for 83% of the average US household’s food-related emissions, far outweighing the 11% linked to how far it had travelled. No matter how close to the food source you are, nothing measures up to eating less meat, says Julie Sinistore, senior project director in WSP’s US sustainability, energy and climate change team: “A localized diet might reduce your greenhouse gas emissions, but a plant-based diet that isn’t necessarily local will reduce it by eight times as much.”

What you see is what you eat

But can people be persuaded to eat differently? Food is deeply personal. It is tied to our identities, memories, culture and sense of place. With governments unlikely to outlaw meat consumption, the biggest impediment to the adoption of more plant-based diets remains individual choice. And while vegetarianism and veganism are gaining traction in some societies, demand for meat is going up as the global population grows and more people adopt a Western diet.

One component of a sustainable urban food system is a built environment that encourages consumption of healthy, sustainable food, says Norford. “Your physical surroundings, especially in a city, have a huge impact on how you behave around food, what you eat and the food choices you make,” she says. “If you’re walking down a city street or taking public transportation and you’re exposed to advertising for unhealthy foods, or if there are fast-food stands all around you and that’s what is easy and convenient on your way home, those are the choices people will make.”

Now imagine a different reality. You walk out of work at the end of a busy day. A food truck awaits you, offering affordable meals made with fresh fruits and vegetables, picked that day from your local urban farm just across the street. You grab a snack and head home to prepare dinner for the night, pulling from your backyard garden or indoor hydroponic system. Norford describes a pilot project in Copenhagen, led by the urban planning firm Gehl, which involved the installation of edible gardens, pop-up furniture and food trucks serving meals aligned with the Planetary Health Diet. “There are many different food environment interventions that can help make healthy and sustainable foods the convenient choice,” she says.

Part of this is reacquainting city dwellers with where their food comes from — and it is here that urban farming can have an impact far beyond what is actually grown. This has been the most significant legacy of the Roimata Food Commons project in Christchurch, New Zealand. When coordinator Michael Reynolds first started the project, he had many conversations with local people who didn’t know much about how food is grown. “That is changing. Our customers are realizing a lot more about what is in season at particular times of the year in our region, and it is breaking cycles and setting up much healthier intergenerational patterns. That is the bit of this work that really excites and drives me. We’re trying to shine a light on the way the food system works or doesn’t work for people, and inspire them to do things differently.”

Meanwhile, outside the city …

Reynolds doesn’t see urban agriculture as the whole solution — he wants it to be an additional source of healthy food for the community, rather than the only option available. “It is not adding resilience to the food system if people are reliant on one food source for everything they need,” he points out.

We will still need large-scale agricultural production — which means we also need to address the environmental impact of current farming practices. “Today, our food is grown in a very agriculturally intensive, carbon-intensive, pesticide and fertilizer intensive way,” says Adarsh Varma, an economist and director in WSP’s UK advisory team. “Commercial food production creates enormous amounts of waste and CO₂ emissions at the cost of biodiversity. We’re clearing land, polluting rivers and creating a lot of other environmental problems that we just can’t see. We are blind to it.”

Like other sectors, agriculture is under pressure to reduce its carbon emissions — which presents an opportunity for a bigger-picture rethink on how we use land. There is plenty of scope for agriculture to mitigate its contribution to climate change, says Jenn Packer, a decarbonization adviser at WSP, based in Ontario. For example, biogas from by-products such as manure could be a source of green energy to power farming operations, or upgraded and blended into natural gas supplies. In the longer term, the development of a green hydrogen supply will enable the production of near-carbon-neutral fertilizer, while biochar — made by thermal conversion of organic materials in a low-oxygen environment — could improve soil quality and sequester carbon.

“Agriculture is currently a source of carbon but it also holds the potential to be a carbon sink,” says Packer. “There are various farming techniques that can achieve emissions removal, including no-till planting, enhancing soils with cover crops, making better use of crop residues and mixing trees with agricultural land. Net-zero opens the door to new ways of creating carbon sinks and rethinking agriculture practices.”

It is much harder to quantify the carbon sequestered by nature-based solutions in comparison to industrial ones: often it can only be estimated, says Packer. But the fast-developing field of natural capital valuation means that it is increasingly possible to put a financial figure on the wider ecosystem services that nature provides — and therefore to drive more sustainable ways of managing the environment.

Varma advises investors and developers on the economic impact of projects and, over the past decade, he has noticed a fundamental shift in how land is valued and how the costs of different activities are calculated: “You can make a lot of money by investing in certain types of industrial activity, but if it damages the environment or creates social problems, then increasingly advisers will not make that kind of decision,” he says.

Varma’s job is to capture the true cost of a project, including all of the financial, environmental and social impacts. For example, if a development destroys green space, there will be a monetary and environmental cost associated with a higher flood risk or greater reliance on air conditioning. If industrial activities worsen air quality, there might be a financial cost linked to absences from workers getting sick. “We are increasingly able to monetize the damage we are causing to the environment and the benefits of reducing carbon and protecting or enhancing nature,” he says.

This is also being reflected in regulations: in the UK, new developments or changes in land management must now assess the impact on biodiversity and are required to deliver a net gain of 10% over a period of at least 30 years.

As a result, developers are beginning to recognize the potential value in leaving land wild, designating it for agriculture or including greenbelts in new projects, says Varma. To build on this, his team are looking to create a catalogue of ecosystem services that can first be measured, then monetized. “This will help us to develop innovative business models to connect sellers such as land owners and farmers with buyers, such as insurers, utilities and local authorities.”

Technology to the rescue

But could the world realistically feed 10 billion people without intensive farming methods? This is the subject of much impassioned debate. One study found that a global conversion to organic agriculture would reduce nitrogen and pesticide use, but require more land to produce comparable yields. Others argue that only by abandoning such destructive practices can we hope to bring about the necessary transformation of food and agricultural systems. The growing agroecology movement focuses not only on working with local ecosystems using techniques such as crop diversification, natural fertilizers and rainwater collection, but on empowering small farmers and securing land rights.

Food technology is also evolving rapidly: tomorrow’s cities may feed themselves in ways we can’t yet contemplate. While labs are continuing to explore new ways of creating animal-free meat and dairy, one of the fastest-growing models is vertical farming — a high-tech, high-yield method that’s a million miles away from backyard gardening. These indoor facilities provide a controlled environment to grow plants year-round in stacked beds, without the need for vast swaths of land. They also use significantly less water and fewer chemicals than conventional farming. But they are a long way off being able to compete with conventional farming on cost — since indoor agriculture doesn’t benefit from free use of the sun, LED lights are a major cost and energy suck, as are the environmental controls and heating and cooling systems. As of now, the carbon footprint of a vertical farm is significantly higher than a greenhouse of similar size. They are also only capable of producing a handful of crops — predominantly leafy greens.

“To decrease costs, we need more plants adapted to those systems,” says John Reich, scientific program director for urban food systems at the Washington DC-based Foundation for Food & Agriculture Research. Tomatoes, green beans, cucumbers and zucchini are ideal candidates to grow indoors and vertically, while space-hungry staple crops such as wheat, corn and rice may never be compatible. “With current production methods, I don’t think it’s possible for a city to feed itself and to supply all the diverse fresh fruits and vegetables a consumer wants,” says Reich. “Our dietary patterns are just not based on the growing season. But local food sheds are still an important part of our food system in that they can complement other food sources and make us more self-sufficient and resilient to shocks.”

Another promising area of research is called precision agriculture, which Reich says could make farming more efficient overall. This approach includes developing drought and heat-resistant crops, reducing water and fertilizer use while increasing yields, and even adapting plants so they can photosynthesize more efficiently. Precision agriculture technology is still in its infancy, but could eventually be applied to crops in both rural and urban areas. In cities where the soil may be contaminated — for example, with heavy metals — precision farming practices and indoor farming could together offer an alternative to traditional urban farms.

No food wasted

Increasing production can help feed more people, but we still have to tackle one of the major barriers to building a sustainable global food system: food waste. The United Nations Food and Agriculture Organization estimates that one third of the world’s food is lost or wasted every year. Urban agriculture could help to reduce waste at an individual level, by making consumers more aware of the effort and resources that goes into producing food. At a commercial scale, meanwhile, by-products that are currently thrown away are becoming new inputs to the process.

Diana Bennett, food and beverage market leader within the energy, resources and industrial group at WSP, cites the example of one client that has developed a way to break down its agricultural waste, release the carbohydrates and convert them to sugar. This could offer an alternative to the use of large land parcels to grow corn for corn syrup, she says.

Another company takes the carbon output from commercial boiler systems and uses it to feed algae, which is harvested to make spirulina and other health-food additives. Food waste can also feed insects, which are rich in protein and healthy oils. “There are several companies out there that grow insects for further processing and use in pet food, and they’re trying to do it for human food as well,” Bennett says.

From home hydroponics to precision-engineered crops, the future of food promises to look very different to today. And it needs to, given how far away today’s production and supply chains are from being healthy, resilient, carbon-neutral and in balance with nature.

For cities, concepts such as urban farming and local production are not about harking back to some historic rural idyll. If we do succeed in creating a sustainable global food system, it will be a first. Food scarcity and insecurity have been constants of the human story since our very earliest days. The challenge may be huge, but there’s never been a better time to change the narrative.