Potential of urban green spaces for supporting horticultural production: a national scale analysis

Lael E Walsh,Bethan R Mead,Daniel Evans,Natalia Falagán,Charlotte A Hardman,Sofia Kourmpetli,Lingxuan Liu,Jess Davies

doi:10.1088/1748-9326/ac4730

Abstract

As urban areas and land-use constraints grow, there is increasing interest in utilizing urban spaces for food production. Several studies have uncovered significant potential for urban growing to supplement production of fruit and vegetables, focusing on one or two cities as case studies, whilst others have assessed the global scale potential. Here, we provide a national-scale analysis of the horticultural production potential of urban green spaces, which is a relevant scale for agri-food and urban development policy making using Great Britain (GB) as a case study. Urban green spaces available for horticultural production across GB are identified and potential yields quantified based on three production options. The distribution of urban green spaces within 26 urban towns and cities across GB are then examined to understand the productive potential compared to their total extent and populations. Urban green spaces in GB, at their upper limit, have the capacity to support production that is 8× greater than current domestic production of fruit and vegetables. This amounts to 38% of current domestic production and imports combined, or >400% if exotic fruits and vegetables less suited to GB growing conditions are excluded. Most urban green spaces nationally are found to fall within a small number of categories, with private residential gardens and amenity spaces making up the majority of space. By examining towns and cities across GB in further detail, we find that the area of green space does not vary greatly between urban conurbations of different sizes, and all are found to have substantial potential to meet the dietary needs of the local urban population. This study highlights that national policies can be suitably developed to support urban agriculture and that making use of urban green spaces for food production could help to enhance the resilience of the national-scale food system to shocks in import pathways, or disruptions to domestic production and distribution.

Highlights

Meeting the dietary needs of growing urban populations in a sustainable manner presents a significant challenge, under the limitations of decreasing land availability due to climate change and land degradation, and a need to preserve natural resources and protect biodiversity
We explored three options for the allocation of growing space to the six crop categories: (a) an equal split where each polygon was divided between the six fresh fruit and vegetable (FF&V) categories described above; (b) a split proportionate to domestic production, where each polygon was divided to match the area of land currently under commercial FF&V production in the United Kingdom (UK), as reported by DEFRA (2019), and (c) a split based on economic value where each polygon was divided according to the crop value of each crop category in the DEFRA (2019) dataset
We estimated that urban green space could support production of 20.70–22.41 metric tons (MT) of FF&V per year in Great Britain (GB), if all urban green spaces were utilized and expected average crop yields were achieved

Summary

Introduction

Meeting the dietary needs of growing urban populations in a sustainable manner presents a significant challenge, under the limitations of decreasing land availability due to climate change and land degradation, and a need to preserve natural resources and protect biodiversity. Urbanization can drive land use change and contribute to the reduction in available land for agriculture (Satterthwaite et al 2010, Barthel et al 2019). Urban dwellers are expected to form 67% of the global population by 2050 (UN Department of Economic and Social Affairs 2018), and new urban land will need to be designated to support this trend (Gao and O’Neill 2020). These population and land use trends are driving increasing global interest in incorporating food production into the urban landscape. We focus on urban horticulture the production of fruit and vegetables

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Conclusion