By 2030, more than 60 percent of the world's populations will live in cities. This creates an enormous food system challenge, particularly when you consider that most of the urban growth between now and 2030 will occur in Africa and Asia. These regions already suffer from high malnutrition rates and are more vulnerable to climate change and price shocks because of their heavy reliance on markets.
Until now, the development sector has paid little attention to urban populations and there is, therefore, limited knowledge of the complex mechanisms of urban food and health systems in low and middle income countries. It is, however, known that inequality spans both across and within cities. The lowest quintiles of urban populations can be as vulnerable, if not more, than their rural counterparts.
In high-income countries, the issue of urban food systems has already started to come to the forefront of local policy agendas. Urban food systems must now become an international development priority if we are to feed growing city populations in low and middle income countries.
Providing everyone with a healthy and sustainable diet will require innovative approaches and, crucially, the rapid advance of new technologies. Low and middle-income countries leapfrogged straight to mobile phone technologies, bypassing the growth of landlines in high-income countries. Many are now asking whether we can we do the same with food system innovations.
Already in high income countries, there has been an increased interest in urban agriculture through initiatives such as city farming, rooftop gardens and locally sourced movements such as farmers markets. This has led to the rise of Controlled Environment Agriculture (CEA), the umbrella term for urban farming techniques such as hydroponics, aeroponics, aquaponics, farming using LED grow lights and vertical farms. If CEA's efficiency increases and its costs go down, CEA could contribute substantially to improving urban food and nutrition security. These new methods of agriculture actually provide many advantages over traditional methods because they shorten the supply chain and are environmentally sustainable
One example is the London-based "Growing Underground" project, which uses a system of hydroponics and LED grow lights to produce vegetables in underground tunnels built during World War II as bomb shelters. This is just one example of cities turning redundant and abandoned spaces into agricultural space. Vertical farms, such as the Plantagon in Linköping, Sweden and Sky Greens in Singapore, are farms built in tall buildings that could grow food on a large scale within mega cities. The "CityFarm Initiative" at MIT's Media Lab, founded by Caleb Harper, aims to add large vertical farms to office buildings. These farms can use natural sunlight or LED lights and grow hydroponically or aeroponically. China has already invested in research to look at whether these vertical farms can be integrated into its rapidly urbanizing spaces.
Improving the cold chain by making it cheaper and more efficient can also increase access to fresher, nutritious foods for low-income households. Inventions such as the solar powered fridge by The Fridge Factory and Danish Technical Institute (GTZ) and Ian Tansley's Sure Chill fridges that can remain cold for 12 days without power are environmentally friendly and can be used in places with low electricity infrastructure. In the developing world these kinds of technologies are being adopted in areas where power for traditional cooling methods are often too costly or simply unavailable. The Zero-Energy Cooling Chamber is one such technology. Cheap and easy to build using just adobe bricks, sand and water, this sandbox-size contraption produces evaporative cooling chambers that can reduce the temperature of nutrient-dense vegetables and fruits by 15 to 20 degrees, extending their life by a couple of days.
Apps have now also started transforming the food system. Many CEA and urban agriculture systems can be enhanced by connected mobile technologies that indicate the overall health and nutritional requirements of an individual plant. Online grocery stores can also shorten the supply chain and create less food and carbon waste because they deliver only what people are ordering from local suppliers. One example comes from South Korea where they have implemented grocery aisle posters next to bus and metro stops that allow consumers to shop using just a smartphone's camera. With Sub Saharan Africa alone expected to have 930m mobile subscriptions by 2019 there is enormous potential for city and rural populations alike to use and create technologies that enhance the food system.
Innovations like these are in the early stages and many of them are still just pilots. But if taken to scale they could make a big impact on food security for the 5 billion people living in cities by 2030.
To provide nutritious and environmentally sustainable diets for city populations now and in the future, our food system must be revolutionized. This means finding opportunities along the entire value chain to deliver healthier, more nutritious diets for rural and urban populations alike. It means focusing on development goals that relate to the future, not what we've experienced in the past. We can't predict which technologies will have the most impact on the future food system, but we can create a framework for learning and sharing what works on a global basis.