Contents lists available at ScienceDirect Global Food Security journal homepage: www.elsevier.com/locate/gfs Commercial farming within the urban built environment – Taking stock of an evolving field in northern countries Khadija Benis ⁎ , Paulo Ferrão IN+ Center for Innovation, Technology and Policy Research, Instituto Superior Técnico, Avenida Rovisco, Pais 1, 1049-001 Lisbon, Portugal ARTICLE INFO Keywords: Urban agriculture Controlled-Environment Agriculture (CEA) Commercial farming Urban built environment Food security Sustainability assessment ABSTRACT Urban horticulture has historically contributed to the supply of fresh produce to urban dwellers and has been gaining popularity over the last years in the Global North, with growing awareness of environmental and health concerns. Over the past few years, commercial farms have been emerging in major northern cities, promoting a trend of environmentally friendly food, grown in highly efficient installations on top of or in buildings. This paper presents a scoping study, including: (i) a review of the scientific literature addressing environmental, economic and social aspects of commercial farming in urban contexts; and (ii) a consultation exercise to inform and validate findings from the review, consisting of semi-structured interviews with a few practitioners in the Netherlands. The main findings are: (1) while the recent proliferation of commercial farms in major cities shows that these new modes of urban agricultural production are gaining momentum, establishing their viability as compared to conventional agricultural practices is a challenge when it comes to scalability, resource efficiency, and cost-effectiveness; (2) as it is still a relatively new field, very few studies have been conducted to quanti- tatively assess the impacts of commercial farming in urban areas; (3) given the complex environmental, eco- nomic and social dimensions of urban agriculture, holistic decision support tools could help integrating them in urban areas. 1. Introduction Global population is projected to reach almost 10 billion by 2050, resulting in a higher demand for food by around 50% compared to 2013 – in a scenario of moderate economic growth; at the same time, income growth in low- and middle-income countries is expected to hasten a dietary transition towards higher consumption of meat, fruits and ve- getables, requiring changes in agricultural output and intensifying pressure on natural resources (FAO, 2017). However, while an accel- eration in productivity growth is needed, it is also hampered by the fast degradation of natural resources caused by agricultural practices, that have already led to massive land use change in order to meet demand for food, which in turn has amplified the environmental effects. Agriculture and climate change are interconnected: the former not only contributes to the latter, but is also affected by its manifestations. The effects of agriculture on climate change have been largely de- monstrated, mainly through GHG emissions, depletion of underground aquifers, and impacts of tillage, fertilizers and pesticides on soil, air and water quality, and on biodiversity (Clark and Tilman, 2017). Furthermore, the use of fossil fuels, jointly with land degradation such as desertification and deforestation, are the major anthropogenic sources of carbon emissions worldwide (IPCC, 2013). At the same time, rising carbon levels and the effects of global warming on temperatures and precipitations are projected to have impacts on crop yields (Zhang and Cai, 2011). In spite of the uncertainty in defining its net impact on the food system, it is likely that climate change will affect the suitable land area for crops, leading to significant socio-economic costs (Stevanovic et al., 2016). In a context of climate change and increasing urbanization – over two-thirds of global population are projected to be living in cities by 2050 (United Nations, 2014), while some experts are skeptical about the capacity of the biosphere to produce enough food for the entire human population (Gilland, 2006), interest for local production to contribute to sustainable urban food systems has re-emerged among decision-makers (Baker and de Zeeuw, 2015), and the practice of urban agriculture as a food, income and employment generator is likely to expand (Caputo, 2012). Today, urban cultivation has been widely re- cognized not only to enhance food security by shortening and thus https://doi.org/10.1016/j.gfs.2018.03.005 Received 6 November 2017; Received in revised form 22 March 2018; Accepted 24 March 2018 ⁎ Corresponding author. E-mail address: khadija.benis@tecnico.ulisboa.pt (K. Benis). Abbreviations: BIA, Building-Integrated Agriculture; CEA, Controlled-Environment Agriculture; GHG, Greenhouse gas; GWP, Global Warming Potential; PF, Plant Factory; RF, Rooftop farming; RG, RTG, Rooftop greenhouse; SC, Shipping Container; UPA, Urban and periurban agriculture; VF, Vertical Farming; VIG, Vertically-Integrated Greenhouse; ZFarming, Zero- Acreage Farming Global Food Security 17 (2018) 30–37 2211-9124/ © 2018 Elsevier B.V. All rights reserved. T