Leafy green skyscrapers? The potential for localised food systems

There is a mountain of literature on the fact that globally, our food systems will need to change substantially if we are to have any hope of even partially attaining the SDGs.?The pile of information on what precisely such change might look like is considerably smaller.

Strong arguments can be made that concentration and consolidation in production, distribution, and retailing of food introduces considerable vulnerability into food systems (Epting, 2016; and see some of the many papers on Covid impacts).

Localising food systems is one way in which they can be made more resilient to the shocks that may disrupt value chains. There is growing interest in the effectiveness of local agriculture as part of a holistic approach to strengthening food systems and making them more just, equitable and sustainable (Dunning et al., 2015; and many other references). There are social and health benefits too.?Many players are helping to build momentum for localising food systems, from grass-roots farmer and consumer organisations, networks such as the C40 Good Food Cities and their commitments to sustainable, equitable and low-emission food systems, and the private sector.

The idea of local food is as old as agriculture itself.?It’s only in the last 300 years or so of a 10,000-year history that agriculture-based food systems have become global, driven by our use of fossil fuels (Smil, 2018).

Small gardens close to or surrounding dwellings already play an important role in food production in both lower- and higher-income countries. In the UK, for example, there are about 330,000 allotments (small gardens of roughly 250 m2 or 0.04 ha, owned by the local community), with 90,000 people on the waiting list for one. There are few estimates of potential production, though in the UK allotments in three cities provide their urban populations with enough fruit and vegetables for about 30 days per year (Grafius et al., 2020). The potential is likely very much higher.?Aggregated data on home garden production in lower-income countries do not appear to exist, although we know that very small farms of ≤2 ha contribute about 30% of most food commodities in many parts of Sub-Saharan Africa, Southeast Asia and South Asia (Herrero et al., 2019). About 40% of urban households in Africa are thought to engage in some kind of urban farming practice (Lee-Smith and Lamba, 2015).

The potential of local home food production in both urban and rural landscapes could be substantial, even in environments that are not very conducive to agricultural production, using greenhouses and other protected environments (McCartney and Lefsrud, 2018).?There are many old, infant and new technologies that could contribute (Orsini et al., 2020).?Singapore aims to produce 30% of its nutritional needs by 2030 from urban farming using a wide variety of new technologies .?Urban agriculture often revolves around controlled environment agriculture (CEA), on, under or above the ground. One example of CEA is vertical agriculture, proposed around the turn of the century as a means of producing fresh food using less water and fossil fuels than outdoor farming – the vision of one early proponent was to grow crops in city skyscrapers, using drip irrigation, hydroponics and aeroponics (Despommier, 2009). Commercial production companies using CEA (of which there are quite a large number) are concentrating on leafy greens, with big increases in yields per unit area of land compared with traditional farming.?But is it a technology that can be scaled up massively?

There are two big challenges currently. CEA may have very large start-up construction and equipment costs, so despite the potentially very large yield benefits that may accrue, pay-back periods may be long. Second, CEA using current technology has very large energy needs: lighting, temperature and humidity control, and carbon dioxide and fertilizer inputs.

Despite these challenges, the application of cutting-edge technology is starting to change the outlook for CEA. Investment is increasing rapidly, and by some estimates, the CEA market will be worth more than USD 170 billion by 2025.

In summary, for the foreseeable future, CEA is not going to provide food for your entire diet; but for vegetables and green leafy crops, it has considerable potential and in some places is already profitable, on a par with more traditional production methods. There are considerable efficiency gains to be realised from CEA – land, labour (because much of the labour input can be supplied by robots and/or automated systems), and water (Avgoustaki and Xydis, 2020). For industrial / high-input CEA uptake at massive scale, addressing the energy challenge will be key. For lower-input CEA that may be appropriate and viable for low- and middle-income countries, assessments are needed that can inform investment decisions with respect to the SDGs and the synergies and tradeoffs that may arise with specific approaches.?

References

Avgoustaki, D.D. and Xydis, G., 2020. How energy innovation in indoor vertical farming can improve food security, sustainability, and food safety? Advances in Food Security and Sustainability, 5, p.1. doi: 10.1016/bs.af2s.2020.08.002

Despommier, D., 2009. The rise of vertical farms. Scientific American, 301(5), pp.80-87.

Dunning, R., Bloom, J.D. and Creamer, N., 2015. The local food movement, public-private partnerships, and food system resiliency. Journal of Environmental Studies and Sciences, 5(4), pp.661-670.

Epting, S., 2016. Participatory budgeting and vertical agriculture: A thought experiment in food system reform. Journal of Agricultural and Environmental Ethics, 29(5), pp.737-748. DOI 10.1007/s10806-016-9631-x

Grafius, D.R., Edmondson, J.L., Norton, B.A. et al. Estimating food production in an urban landscape. Sci Rep 10, 5141 (2020). https://doi.org/10.1038/s41598-020-62126-4

Herrero M, Thornton PK, Power B, Bogard J, Remans R, Fritz S, Gerber J, Nelson GC, See L, Waha K, Watson RA, West P, Samberg L, van de Steeg J, Stephenson E, van Wijk M, Havlik P (2017). Farming and the geography of nutrient production for human consumption. The Lancet Planetary Health 1, 33-42.

Lee-Smith, D. and Lamba, D., 2015. Nutrition and urban agriculture in sub-Saharan African cities. Watch Article, 7. https://www.righttofoodandnutrition.org/files/Watch_2015_Article_7_eng_Nutrition%20and%20Urban%20Agriculture%20in%20Sub-Saharan%20African%20Cities.pdf

McCartney, L. and Lefsrud, M., 2018. Protected agriculture in extreme environments: a review of controlled environment agriculture in tropical, arid, polar, and urban locations. Applied Engineering in Agriculture, 34(2), pp.455-473. https://doi.org/10.13031/aea.12590

Orsini F et al., 2020. Features and functions of multifunctional urban agriculture in the Global North: a review. Front. Sustain. Food Syst., https://doi.org/10.3389/fsufs.2020.562513

Smil V, 2018. Energy and Civilization: A History. MIT Press.