A Global Geospatial Ecosystem Services Estimate of Urban Agriculture

Abstract

Though urban agriculture (UA), defined here as growing of crops in cities, is increasing in popularity and importance globally, little is known about the aggregate benefits of such natural capital in built‐up areas. Here, we introduce a quantitative framework to assess global aggregate ecosystem services from existing vegetation in cities and an intensive UA adoption scenario based on data‐driven estimates of urban morphology and vacant land. We analyzed global population, urban, meteorological, terrain, and Food and Agriculture Organization (FAO) datasets in Google Earth Engine to derive global scale estimates, aggregated by country, of services provided by UA. We estimate the value of four ecosystem services provided by existing vegetation in urban areas to be on the order of $33 billion annually. We project potential annual food production of 100–180 million tonnes, energy savings ranging from 14 to 15 billion kilowatt hours, nitrogen sequestration between 100,000 and 170,000 tonnes, and avoided storm water runoff between 45 and 57 billion cubic meters annually. In addition, we estimate that food production, nitrogen fixation, energy savings, pollination, climate regulation, soil formation and biological control of pests could be worth as much as $80–160 billion annually in a scenario of intense UA implementation. Our results demonstrate significant country‐to‐country variability in UA‐derived ecosystem services and reduction of food insecurity. These estimates represent the first effort to consistently quantify these incentives globally, and highlight the relative spatial importance of built environments to act as change agents that alleviate mounting concerns associated with global environmental change and unsustainable development.

Excess phosphorus from compost applications in urban gardens creates potential pollution hotspots

“…For example, if UA expanded to cover 3% of the land area of CRWD (less than the current extent of UA in Montreal (Metson and Bennett 2015a) and less than Scenario 1 in Grewal and Grewal (2012), in which 80% of vacant lots in Cleveland are used for UA), then the resulting P inputs would be more than 5×the current cumulative P inputs to the watershed. Clinton et al (2018) estimated that UA could produce 100-180 million tonnes of food per year globally, providing ecosystem services worth $80-160 billion. However, achieving these yields with a 2.5% PUE would result in the buildup of P in urban soils of approximately 1.7 Tg P/yr, a significant component of the global P budget (Bennett et al 2001).…”

“…Urban agriculture can take a variety of different forms, but most outdoor urban agriculture (including backyard and community gardens, as well as commercial urban farms) typically relies heavily on compost-derived nutrients (Metson and Bennett 2015a). If UA can increase urban nutrient recycling, that would add to a number of other environmental, social, and cultural benefits that have been described (Recknagel et al 2016, Artmann and Sartison 2018, Clinton et al 2018.…”

Does Urban Agriculture Improve Food Security? Examining the Nexus of Food Access and Distribution of Urban Produced Foods in the United States: A Systematic Review

“…Applying a distribution lens to the existing literature yields similar results to the food access analysis in that several articles theorize idealized distribution systems, showing the capacity of hypothetical urban and peri-urban farms to supply distribution networks that meet most urban food demands [40,[53][54][55][56][57]. Others highlight barriers and challenges farmers face in practice around distributing their produce to those in need while maintaining their operations [72,73].…”

“…To address those critics, the localized food systems scholarship offers a fair amount in the landscape ecology and planning literature theorizing the high productive potential of UA to address food insecurity [2,18,53,54]. Spatial analyses such as those cited above provide insights into theoretical access, while not addressing the policy, governance and practical barriers that would need to be overcome in order to realize the potential.…”

“…The optimal siting analyses, using census block group data, promote food justice by prioritizing low-income communities when siting urban farms in effort to increase access [55,56]. From a global quantitative mapping analysis done with Google Earth Engine, urban agriculture was found to "positively influence food production, nitrogen fixation, energy savings, pollination, climate regulation, soil formation, and the biological control of pests, services that are worth, as a whole, as much as $160 billion" [53]. This study suggests the ability of urban agriculture to improve food security on a global scale (acknowledging significant country-to-country variability).…”