Written by: Miriam Dobson. Dr Dobson holds a PhD in urban agriculture from the University of Sheffield and currently works in the field of green space, forestry and public health
If you grow tomatoes on your balcony, keep a basil plant on your windowsill or try out home hydroponics – you’re participating in urban agriculture. From pot plants to more intensive subsistence farming within urban boundaries, urban agriculture can help combat several key problems in the urbanised, globalised world food system: it can reduce food miles from farm to table, cut carbon emissions and fight food poverty; offer avenues to more local employment and improve the health and wellbeing of city residents; and protect biodiversity, from plants to bees and birds.
In this brief introduction to urban agriculture and its place in the world of the future, we will explore its possible benefits and potential to feed a city, presenting a broad overview of why urban agriculture is becoming increasingly relevant within the global food supply chain.
What Do We Mean by ‘Urban Agriculture’?
Urban agriculture is understood to be any form of food production – horticulture or livestock holding, for example – taking place within city boundaries. On the other hand, ‘peri-urban agriculture’ refers to agriculture that is carried out in semi-rural areas on the borders of cities, outside residential areas but not fully in rural farmland.
It is estimated that around 800 million people worldwide engage in some form of urban agriculture (Orsini et al., 2013), from personal food-growing in gardens and backyards, to community projects transforming vacant urban spaces into gardens; to rooftop and vertical food production; to controlled-environment agriculture, such as hydroponics, taking place underground and indoors.
Urban agriculture in the 21st century is a picture of diversity, with new technologies meeting old horticultural and agricultural practices. For example, according to the National Society of Allotment and Leisure Gardeners, there are 330,000 allotment gardens in the UK, which provide traditional horticultural growing space, while new technologies such as the ‘Internet of Things’ enable hydroponics farmers to remotely monitor their growing systems.
The spectrum of urban agricultural forms provides an exciting new way to look at our cities: rooftops, walls, and underground spaces are now also potential sites of food production alongside traditional soil-based growing spaces.
In the Global South urban agriculture looks different than in the Global North, thanks to varied histories and climates. It also fulfils different purposes around the world, from food provision for subsistence and to combat food insecurity, to its practice as a leisure activity that contributes more to wellbeing and lifestyle with the added bonus of producing fresh and healthy food.
Expanding a Limited Resource
As the climate and our relationship to the land changes, urban agriculture will become increasingly important. The UN has estimated (opens PDF) that 68% of the world’s population will live in cities by 2050; in some countries, such as for example the UK, as much as 90% will be urban residents by this point. Urbanisation has several consequences for the food system and the wider environment. Growing urban populations necessitate the geographical expansion of cities, and this expansion often encroaches on prime agricultural land often located immediately outside city limits, which historically would have produced food for city residents: urban areas are forecast to increase in land cover by 1.2 million km² globally by 2030 compared to the turn of the century (Seto et al., 2012).
This is on top of the fact that agricultural land is already a limited resource, facing increasing problems with soil degradation and desertification as the post-1950 industrialised ‘Green Revolution’ agricultural techniques run their course in stripping nutrients from the soil and contributing to soil erosion.
The demands that a growing global population places on the food system contribute to this. For example, the density of city populations means that their agricultural land requirements are vastly greater than their areal extent, with London requiring an area equivalent to 40% of the UK’s total agricultural land to meet its food demands despite occupying less than 1% of the UK’s geographical area (Deelstra and Girardet, 2001). Cities, therefore, rely on importing food to meet their needs, which makes them vulnerable to shocks in the global food system.
Not to mention that cities themselves are often sites of great inequality. ‘Food deserts’ – areas of a city where there are no opportunities to purchase fresh and affordable fruit and vegetables nearby – are a growing problem in the Global North. Access to fresh, healthy and affordable food is a key tenet of improving the livelihoods of many disadvantaged urban residents. Sustainability and social justice therefore go hand-in-hand when it comes to the food system. Participation in urban agriculture can be one solution, as it produces fresh food while giving people the opportunity to increase their autonomy by providing for themselves.
Urban agriculture also has the potential to combat the negative impacts of the global food system on the environment. It can support biodiversity in cities, forming part of the network of urban green infrastructure, and providing support to key species such as pollinators and earthworms. It can also help mitigate the urban heat island effect – the temperature increase in cities because of waste heat given off by the dense infrastructure and populations. Finally, urban agricultural areas can absorb rainfall, mitigating the impact of storms that may otherwise cause flooding.
Soil-based urban agriculture such as growing in allotments or community gardens also provides participants with the opportunity to improve their wellbeing by spending time outside. Research has demonstrated that a single session of allotment gardening, for example, has comparable wellbeing benefits to more formal horticultural therapy, and that allotment gardeners self-report a wide spectrum of well-being benefits related to spending time on their plot.
Can Urban Agriculture Really Feed Us?
This all leads to a fundamental question: just how much food can we grow in our cities, and how much can this contribute to a more sustainable and equitable food system now and in the future?
There is an increasing body of research developing methods aimed at quantifying the productive capacity of urban agriculture. In the United Kingdom, the MYHarvest project, which is yet to report its results, conducted the first nationwide survey of own-growers (in allotments, private gardens and community gardens; Edmondson et al., 2019). Recent publications from a pilot study in just one city, Leicester, focused on allotments and yielded promising results: When fully cultivated, the current allotment land could feed 10,000 people (or 3% of the city’s population on 1.5% of the land) their ‘five a day’ (British government healthy eating guidelines, around 400g of fruit and vegetables) diet (Edmondson et al., 2020a).
An exploratory study that looked at the potential available land space in another UK city, Sheffield, found that there was sufficient potential land available for soil-based urban agriculture to feed more than 100% of the city their five-a-day diet (at maximum possible cultivation); at only 10% cultivation of potential land, 12% of the city’s population could be fed (Edmondson et al., 2020b). This is a promising start in advance of the nationwide survey reporting back its findings: It demonstrates the importance of expanding the amount of food growing that takes place in cities to bring sustainable environmental and wellbeing benefits to all; the opportunities now lie in the hands of communities and policymakers to help this happen.
Expanding to include other forms of urban agriculture is key to answering the question of the potential production that can take place in cities. This will involve researching not only soil-based agricultural practices, but also how much of the other infrastructure in cities, such as rooftops and car parks (‘grey infrastructure’) can be used to grow food with systems such as hydroponics.
Of course, this brief introduction leaves open more detailed questions relating to productive capacity: How capable are cities of feeding themselves, really? What stands in the way of attaining the full potential of urban agriculture? What skills would citizens require in order to truly take advantage of urban food production? How much untapped potential is there in cities for future agricultural projects? What can we learn from diverse forms of urban agriculture around the world?
¹Deelstra, T., & Girardet, H. (2000). Urban Agriculture and Sustainable Cities. In N. Bakker, M. Dubbeling, S. Gundel, U. Sabel-Koshella, & H. de Zeeuw (Eds.), Growing Cities, Growing Food: Urban Agriculture on the Policy Agenda (pp. 43-66). Feldafing: ZEL.
Peer review declaration: This is a peer-reviewed article written by an academic researcher. It has been put through double-blind peer review.