The taste of resilience Interdisciplinary project on the effects of urban agriculture on the resilience of the food system of Amsterdam – The Netherlands

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University of Amsterdam

The taste of resilience

Interdisciplinary project on the effects of urban agriculture on the

resilience of the food system of Amsterdam – The Netherlands

Naut Loots – Spatial Planning (10289216)

Lars de Ruig – Earth Science (10193197)

Lynn Snijder – Human Geography (10213155)

Supervisor: Dr. M. Hamers

Word count: +/- 7500 (excl. references) 22-5-2014

KEYWORDS: Urban Agriculture - Urban and Ecological Resilience - Amsterdam - Food Systems

ABSTRACT: This paper gives a quantification of the current resilience of the food system in Amsterdam

and the change of resilience of the food system as a result of implementing urban agriculture on brownfield sites and in free office spaces. Using an interdisciplinary framework, the quantification of the resilience of the food system in Amsterdam is made. As part of the framework, the potential of urban agricultural production on brownfield sites and in free office spaces is estimated. The results will consist of an estimation of the change in resilience of the food system due to the implementation of urban agriculture base on six criteria; local food production, soil pollution, biodiversity, community building, intake of nutritious & healthy food and self-reliance on fresh food production. It appears that urban agriculture could contribute for 1,83% in the total food consumption additionally the results indicates that urban agriculture could increase the resilience of the food system if measures are taken.

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2 Introduction

Food demand increases and puts pressure on urban food systems as a result of world population growth. Furthermore the ratio between urban to rural dwellers has shifted from 1:6,7 to 1:1 in the past century and is predicted to shift even further to 3:2 by 2025 (Satterthwaite, McGranahan & Tacoli, 2010; Sakdapolrak et al., 2008; Zezza & Tasciotti, 2010). Despite the decline of rural dwellers, global agricultural production was able to meet the demands of the growing urban regions using energy- and greenhouse gas emission-intensive food. Even though this development resulted in high economic growth, it also causes the global food system to suffer from negative social and environmental impact (Mougeot, 2006; Grewal & Grewal, 2011; Feenstra, 2002). Hereby the food system is defined as “The chain of activities beginning with the production of food and moving on to include the processing, distribution, wholesaling, retailing and consumption of food and eventually the disposal of waste” according to The American Planning Association (2006, p. 54, 55). Besides the enhancement of global warming due to of the use of energy- and greenhouse gas emission-intensive food, climate change could negatively change the productivity of food production on a global scale (Feenstra, 2002; Satterthwaite et al., 2010). Consequently, global food security is becoming more fragile and vulnerable.

On a smaller scale level, cities appear to be strongly reliant on the global food system to maintain their own food security. This dependence negatively affects the sustainability, ecological and economical resilience of the city and its food system (Grewal & Grewal, 2011). Additionally, the vulnerability of the global food network increases the pressure on urban food system even further (Satterthwaite et al., 2010).

Several studies, such as Lovell (2010) and Armar-Klemesu (2000), have shown the potential for urban agriculture (UA), which is defined by Mougeot (2000, p.10) as ‘an industry located within

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or on the fringe of a town, a city or a metropolis, which grows or raises, processes and distributes a diversity of food and non-food products, (re-)using largely human and material resources, products and services found in and around that urban area, and in turn supplying human and material resources, products and services largely to that urban area’. Adopting UA appears to increase local food security, produces healthier and fresher food and relieves stress of the global food system (Zezza & Tasciotti, 2010; Mougeot, 2006; Armar-Klemesu, 2000; Lovell, 2010). Consequently, UA could play a major role in solving the problems of food production and food security on an urban scale level and thereby relieving pressure of the global food system.

Despite the benefits of UA, knowledge gaps exists between disciplines (McClintock, 2010). Most conducted studies analyse UA from a mono-disciplinary perspective. For example, Armar-Klemesu (2000) approached UA using ecology while Nugent (2000) focuses on economics. UA is complex in nature, as there are many stakeholders involved from different disciplines (McClintock, 2010). Consequently, problems of the implementation of UA should be approached using an interdisciplinary perspective (Repko, 2012). Due to the lack of interdisciplinary research on this topic, knowledge gaps exist and problems arise with the implementation of UA (Mougeot, 2000; McClintock, 2010). For example, policy makers often do not know whether the government or residents should take initiative and adopt UA (Nugent, 2000) or according to Mougeot (2006) UA is associated with urban land squatting and is viewed as a socioeconomic problem instead of a solution. Therefore, this paper aims to fill in existing knowledge gaps on UA and gain more understanding of the uses of UA.

In the seventeenth century, the food system in Amsterdam was already of global scale. In this Golden Age spices were imported and transported from different location in Asia to Amsterdam, where these spices were sold to other traders (Amsterdam.nl, 2002). Currently, the food system of

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Amsterdam is mostly managed globally. Amsterdam has a total food consumption of 529 million kilograms per year. and a meal travels 33,000 kilometres on average before it reaches the consumer (Rabobank, 2012; Gemeente Amsterdam, 2013; Gemeente Amsterdam, 2014a). Consequently, Amsterdam can be seen as an example city that is dependent on the global food system. Therefore, this paper aims to identify possibilities for UA to improve the resilience of the food system in Amsterdam.

To achieve the aim of the research, the following question will be asked: How can urban agriculture contribute to a more resilient food system in Amsterdam? The concept of resilience has its basis defined as the ability of a system to return to an equilibrium state after a destabilizing disturbance (Holling, 1973). The resilience theory can be applied in several disciplines and the more disciplinary-specific definitions will be described in the theoretical framework section (see page 6-12). The change of resilience as a result of adopting UA in the city will be measured by firstly calculating the potential of UA on unused bare areas and empty buildings in the city. Subsequently, using several formed criteria, the current level of resilience of the food system of Amsterdam will be estimated. Lastly, the change of resilience when adopting UA in the city will be estimated based on the calculated potential of UA. In this estimation only fresh food, fruit and vegetables, will be taken into consideration as most data is available in this sector (Grewal & Grewal, 2011). Our research team consists of three specialists covering the disciplines of Human Geography, Spatial Planning and Earth Science. The field of Earth Science will cover the topics of ecological resilience, nutrient cycles and green urbanism, Spatial Planning will focus on Brownfield Sites and Human Geography will use the concept of urban resilience. These concepts will cover most aspects of UA and integrating these concepts should result in interdisciplinary insights.

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The paper is ordered as follows; the first section will give an overview on the used mono-disciplinary theories that provide the theoretical framework for this paper. Secondly the methods used in this paper will be explained and thirdly, the results on overcoming common ground and conflicts between mono-disciplinary theories will be given and applied to the gathered data of Amsterdam. Subsequently, the discussion section will discuss on the outcomes of the results and lastly, the conclusion will provide an answer on the main research question.

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6 Theoretical framework

To be able to integrate mono-disciplinary knowledge into the interdisciplinary research, the individual theories and key concepts should be fully understood (Repko, 2012). In this section these theories and key concepts are explained in perspective of each discipline. These theories will be integrated with each other to form the criteria on which resilience will be classified. This process is described in more detail in the methods section (page 13-15).

Earth Science

Green Urbanism theory

One of the first complete definitions of green urbanism is stated by Beatley (2000, p.243) as: ‘Cities that strive to live within their ecological limits’. In this sense, cities must reduce their ecological footprint which requires

the cities to acknowledge their connections with other cities and communities. Lehmann (2010) expanded the theory to a conceptual model for urban design to achieve zero-emission and zero-waste. In Figure 1 the complexity and the interdisciplinary nature of the theory is visualized (Beatley, 2000; Beatley, 2006; Lehmann, 2007; Lehmann, 2010). UA is part of green urbanism and can help to solve arising problems.

Figure 1, the three pillars of Green Urbanism that show the complexity of the theory (Source: Lehmann, 2010)

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The theory consists of 15 principles that act as a framework to guide stakeholders and research on the topic (Lehmann, 2010). Following the scope of this paper, four of the fifteen principles are relevant.

Firstly, according to principle three the city must become zero-waste, meaning the waste should be fully recyclable. The essence of this principle is, that waste should be made into a resource instead of waste, although caution should be taken when considering industrial and e-waste, as these waste treatments are often energy-heavy and toxic (Lehmann, 2010). Secondly, the fourth principle states that the city’s water quality should be high, while water consumption should be low. This can be achieved by using water efficiently by recycling of water while maintaining the quality of water and avoiding toxic pollution in the urban water system (Lehmann, 2010). Thirdly, the fifth principle describes the importance of urban biodiversity, in the shape of green areas and public gardens. Beside the aesthetic value of parks and public gardens, the biodiversity of these elements is essential for habitats, ecosystems, wildlife rehabilitation, forest conservation and the protection of regional characteristics. Using local ecological cycles, such as the nutrient cycle, in combination with green urban spaces could increase the biodiversity in a city significantly (Lehmann, 2010). Lastly, the eleventh principle of green urbanism explains the benefits of a local food supply and short supply chains. UA is named as a possibility to achieve these benefits and creating a more sustainable city and an increase of the city’s food security. Additionally, the principle suggests adjusting our food consumption patterns by consuming less animal products, such as meat (Lehmann, 2010).

The theory of green urbanism is a relatively new theory and therefore it is only barely reviewed. Because of the complexity of green urbanism, state of the art research from several disciplines is required to give insights on the value and effectiveness (Lehnmann, 2010). Furthermore, the

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application of green urbanisms to cities is in an early stage which gives insufficient empirical evidence to confirm the validity. Despite of the lack of verification, several studies show high potential for green urbanism and it has drawn the interest from both the academic and political world (Beatley, 2006; City of Vancouver, 2012; Lehnmann, 2010). Only the four principles as described above will be used as this paper only focuses on the food system. Using additional literature, the validity of the results will be tested, to prevent biased or incorrect results due to a lack of critics on green urbanism.

Ecological Resilience Theory

The resilience theory originates from the ecological disciplines, first described by Holling (1973). Besides concepts of stability and transition, the main-concept is ‘resilience’ and defined by: ‘The persistence of relationships within a system and is a measure of the ability of these systems to absorb changes of state variables, driving variables and parameters, and still persist.’ (Holling, 1973, p.17). The resilience theory can be applied to an ecosystem system and determines the ability of the system to withstand external disturbances. When the resilience and stability of the system are stronger than the disturbance, the system will not shift to another state and will eventually recover to the initial equilibrium. However, if the disturbance is too strong or the frequency of disturbances is higher than the recovery rate, the system will shift between stable states. This regime shift in states could result in unwanted and unexpected changes. The shift back to the previous state could be irreversible, in the sense that more energy is needed to reverse the shift than to maintain the initial state (Holling, 1973; Folke et al., 2004; Folke, 2006; Scheffer et al., 2001; Scheffer et al., 2009; Folke et al., 2010). This way of approaching the stability of an ecosystem is different from the previous accepted theories, such as the management of resources, as it considers unpredictable and irrational behaviour of systems and interaction with variables

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while previous theories only considered the availability of resources (Holling, 1973, Bhamra, Dani & Burnard, 2011).

After the introduction of the concept of resilience by Holling, the theory was widely accepted and expanded significantly. Concepts such as stable states, regimes shifts and irreversibility were added and the application of resilience in other disciplines was analysed (Folke, 2006; Scheffer et al., 2001; Scheffer et al., 2009; Bhamra, Dani & Burnard, 2011). Firstly Holling put resilience in an engineering context and subsequently various researchers applied ecological resilience to social-economical systems and other disciplinary systems (Holling, 1996; Folke, 2006; Folke et al., 2010). Due to the application of the theory in other disciplines, a wide extent of reviews on resilience by other disciplines than ecology have been made. As a result, disciplinary bias is mainly avoided (Folke, 2006; Bhamra, Dani & Burnard, 2011). Even though the resilience theory is widely accepted, criticism arises from the purely qualitative approach of the theory. As there are no methods to measure the magnitude of resilience, it proves to be difficult to implement it in quantitative assessments (Bhamra, Dani & Burnard, 2011).

Nutrient Cycle theory

Although Darwin (1881) and other scientist mentioned early abstract versions of the nutrient cycle, the first to describe the concept of the theory in detail were Dumas and Boussingault (1844). The theory states that organic and inorganic matter move and exchange back and forth between the production of living matter in a closed cycle (Bormann & Likens, 1967; Odum, 1991). When living matter dies, it is decomposed by microorganisms into minerals and nutrients. Subsequently, plants can uptake the minerals and nutrients or they are spread by processes such as surface runoff and leeching. However the spreading of minerals and nutrients will only change the geographical location, where the nutrients and minerals will eventually be cycled through the local food web.

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Every small cycle of every food web forms a large closed cycle on Earth (Odum, 1991; Elser & Urabe, 1999; Ohkuma, 2003). The nutrient cycle theory is highly accepted by most disciplines as there is currently no criticism and forms a basis for other key concepts and processes. For example, Balmford et al. (2002) uses it in an economic context while Esler & Urabe (1999) applies the nutrient cycle theory in an ecological context in relation with farming systems. In this research project, the nutrient cycle theory will be used in relation with ecological resilience and green urbanism, as these relation provide more insights on the current level of resilience of a food system. This is explained in the results section (page 16-19).

Human Geography

Urban resilience

As stated by Campanella (2006) cities are more than the sum of their buildings. They are also thick concentrations of social and cultural matter. Therefore the theory of urban resilience is organised around four key themes of inquiry: metabolic flows, governance networks, social dynamics and the built environment (see Figure 2). When viewing cities as complex adaptive systems, these four themes are of particular significance for the resilience of the urban system (CSIRO, 2007; Leinchenko, 2011). Urban resilience emphasizes

the idea that cities, urban systems and urban constituencies need to be able to quickly recover from shocks and stresses (Leinchenko, 2011). What human geography can contribute to the analysis of urban resilience is identifying the spatial processes that have an influence on the

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sense of community, globalisation, urbanization and food networks. All these processes have an influence on the resilience of the urban socio-economic system (SES) (own insights).

The theory of urban resilience arose from ecological resilience. As explained in the Ecological Resilience section (see page 8-9), the first idea of ecosystem stability, vulnerability and resilience, and came from Holling (1973). Only in recent years the concept of resilience is linked to urban issues. As stated in Coaffee (2008), there is more attention to the way security and risk are part of the build environment because of the growing urban population. Nevertheless, more research is needed to understand disruption and cause recovery of the urban system. Therefore there is not much criticism on this theory yet.

Urban Planning

Brownfield development theory

Cities change all the time, and sometimes a result of this everlasting change are urban vacant sites. After the industrial age, often heavy polluted factories moved far away from cities because of health and safety issues. This is, according to Ferber et al (CABERNET report, 2006), a brownfield site. The official definition according to the CABERNET report (2006) is as followed: “Sites that have been affected by the former uses of the site and surrounding land; are derelict and underused; may have real or perceived contamination problems; are mainly in developed urban areas; and require intervention to bring them back to beneficial use”. However, nowadays brownfield sites do not always have to be polluted (Siebielec, 2012). Brownfield development is used around the world for multiple purposes, and UA is one of them. Transformation of these sites have various positive effects; stops the further degradation of land, increase in ecological and economical value. Important is to look at the history of a site to gain insights about what kind of pollution might be present. This is important to ensure the possibility of safe UA. However, most brownfield are

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currently present outside the centre of Amsterdam and are mostly abandoned factory sites. The concept of brownfield development is implemented differently throughout the world. This is due to the differences in character of the sites, and the possibilities that it might offer. Moreover, these differences in the implementation, ensure that there is not one correct basic theory and brownfield development needs to be addressed individually. This makes brownfield development quite time consuming and difficult to get the desired effect (Siebielec, 2012). In this research brownfield development will mostly be addressed as vacant lots in Amsterdam, and empty office spaces. Later on, will be more clear why these sites were chosen.

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13 Methods

The previous section gave an overview and insights on individual theories and concepts of each discipline. However, in order to combine these theories and concepts, integrative techniques are required as described by Repko (2012 p. 336-348). This section will describe the techniques used in this paper. Furthermore, the methodology of the calculations on the potential fresh food production by adopting UA in Amsterdam are explained. Then lastly, how the change of resilience is quantified, will be described in this section. The steps are visualized in Figure 3.

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14 Integrative techniques

The first part is a theoretical analysis and uses the integrative techniques as defined by Repko (2012, p. 336-348). Two of the integrative techniques are relevant for this paper, the technique of organization and the technique of transformation (Repko, 2012). Firstly, the technique of organization will be used to clarify the relations between ecological and urban resilience. Even though these theories might look similar, they should be used in different ways and should be used parallel (Tidball & Krasny, 2007). However, organization is needed to gain knowledge on the relationship between both theories (Repko, 2012). Secondly, the technique of transformation is used in order to quantify the concept of resilience. Resilience is qualitative in nature and most commonly used this way (Bhamra, Dani & Burnard, 2011). This paper aims to give a more detailed insight into the food system due to UA, and therefore using formulated criteria transforms resilience in a continuous variable. The criteria will be formulated by using the technique of organization on the individual theories to relate them with each other.

Urban agriculture potential estimation

The second part of the process, after the use of the integrative techniques, is an estimation that is made for the potential food production by implementing UA in Amsterdam. This estimation will be based on a calculation that uses the average yield of the primary production type that will be adopted in Amsterdam when implementing UA (Grewal & Grewal, 2011). The the potential food production as a result of implementing UA on usable Brownfield sites and free office space in Amsterdam can be calculated and will be compared with the total food consumption of Amsterdam. This gives insights on how significant the impact of implementing UA will be in

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Amsterdam. Subsequently, data maps of Amsterdam are used to identify the geographical locations in the city where UA can be implemented.

Resilience quantification

The third part of the results, after the potential of UA is estimated, a quantification of the level of resilience of the food system in Amsterdam is made. The individual theories as described in the theoretical framework (see page 6-12) will be related with each other. Again, Repko’s (2012) integrative technique of reorganization will be used on the individual theories with the concept of UA. This will result in relations with the theoretical background and a practical approach of UA. These relations are the basis for the quantification of resilience of the food system of Amsterdam and will act as criteria on which the level of resilience of the food system can be identified. The criteria are subsequently combined with geographical data of Amsterdam, processes with a Geographical Information System (GIS) or other data sets. Consequently, based on the criteria and the data sets, an estimation of the level of resilience of the food system of Amsterdam is made. The last step is to estimate the level of resilience of the food system of Amsterdam after the implementation of UA on brownfield sites and free office space. This is achieve by combining the criteria and data sets with the calculation of the potential of UA in Amsterdam and on which locations in Amsterdam can be implemented, as acquired in the second part of the process. Following these steps should result in an overview of the current level of resilience of the food system in Amsterdam based on several criteria and the change of resilience as a result of implementing UA in Amsterdam on brownfield sites and free office space.

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16 Results

The main concept of this paper is the resilience of the food system. However, as described in the theoretical framework (see page 6-12), both Earth Sciences and Human Geography define resilience differently. The first part of this section will give the results of the application of the integrative techniques to gain insights on the differences and common ground of both theories. Subsequently, the relation between the individual theories and UA are made. The second part of this section describes the calculations made to determine the potential food production for UA in Amsterdam on brownfield sites and free offices. Furthermore, this part is used to show the possible location on which UA could be implemented. The third part consists of the description of the criteria on which resilience will be quantified. These criteria will be subsequently used on available data for Amsterdam to estimate the current level of resilience of the food system of Amsterdam. And lastly, combining the calculations of UA potential and the criteria, the change of resilience of the food system of Amsterdam after the implementation of UA is estimated.

Reorganization of the concept of resilience

Ecological and urban resilience

Even though ecological and urban resilience are closely related, they cannot be seen as the same theory. Hence, the definitions of the related concepts are similar, but fundamental assumptions differ, as the origin of both theories comes forth from different disciplines. As a result, both theories should not be merged, but they should be seen as individual theories (Tidball & Krasny, 2007). Repko’s technique of organization can clarify relations between both theories (Repko, 2012).

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Both theories have the main definition of resilience as the amount of change or disturbance the system can undergo before shifting to another state as it is not capable to restore to the original equilibrium in time. In the case of ecological resilience, the system refers to ecosystems while in urban resilience the system refers to a social system, such as a local community or the city as a whole (Tidball & Krasny, 2007). The relation between these systems is made using the concept of resource dependency, which states that the resilience of a social system is lower when dependent on a risky resource. When an urban system has resource dependency on a low-resilience ecological system, urban resilience will decrease (Adger, 2000; Tidball & Krasny, 2007; Henrik et al., 2010). However, when the urban system is integrated with a high-resilience ecological system, the urban resilience is most likely to increase. In case of UA, this integration can be achieved between the city as urban system and the food system (Alberti, 2004; Colding, 2007; Tidball & Krasny, 2007). The integration of the city and the food system is based on two fundamental concepts (Tidball & Krasny, 2007). Firstly, it appears that diversity is fundamental to retaining functional and structural control against disturbances. In case of ecological systems, resilience increases as a result of increasing biodiversity (Peterson, Allen & Holling, 1998; Elmqvist et al., 2003). Subsequently, urban systems also experience increased resilience as a result of diversity. This diversity is formed by cooperation between stakeholder, such as community members, NGOs, government officials and other groups related to the food system.

Secondly, the concept of self-organization implies that processes and patterns should function on the smallest scale possible. Local ecological processes can strongly influence the regional economy and therefore the food system can benefit if residents manage their own resources on a local scale. It should be noted though, that it the smallest scale only holds if efficiency and benefits allows it (Alberti, 2004; Tidball & Krasny, 2007). Furthermore, by adopting self-organization,

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residents gain more awareness and knowledge on food and food systems which also leads to a higher urban resilience (Tidball & Krasny, 2007).

In conclusion, urban and ecological resilience are different theories but are strongly related. Because urban systems are dependent on the ecological systems of a city, the improvement of the ecological system by for example adopting UA, will also result in an increase of urban resilience. If it is only sought to improve the urban resilience but neglecting the urban ecosystems, efforts will not have as significant impact as an integration of both system will (Alberti, 2004; Colding, 2007; Tidball & Krasny, 2007).

Relations between urban agriculture and theories

The resilience of an urban food system appears to increase when the mean number of cycles that nutrients or minerals make before they leave the system (DeAngelis, 1980; DeAngelis). By adopting UA, food production becomes more localized. The nutrient cycle of the food system has a higher probability to recycle through the system more often, if production is within the same system as consumption. Consequently, higher resilience can be created by localizing food production. This benefit becomes stronger when using organic waste as fertilizer for UA. As a result, the probability of recycling nutrients and minerals through the system increases and hence the resilience of the food system increases (DeAngelis, 1980; DeAngelis et al., 1989; Lehmann, 2007; Lehmann, 2010). The concept of self-organization applies in case of recycling unconsumed organic waste, as when residents manage their own unconsumed organic waste for their urban agricultural activity, nutrients are not transported to another system (Tidball & Krasny, 2007). Biodiversity, which is essential for green urbanism according to principle five (see Theoretical framework, page 6-7), will increase the resilience of ecosystem services and therefore increase the resilience of the food system (Peterson et al., 1998; Elmqvist et al., 2003; Lehmann, 2010). It

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appears that resilience is generated by diverse ecosystems but some overlap between ecosystem services should exist. When a disturbance occurs, the overlapping ecosystem services will support each other which will result in a faster recovery to the initial equilibrium (Peterson et al., 1998; Elmqvist et al., 2003; Colding, 2007). In the context of UA, disturbances caused by drought or floods have faster recovery rates when the resilience is high. For example, plants are often dependent on pollinators in order for them to reproduce. When a hazard disables the only pollinator specie in the city, as a result of low biodiversity, plants are not able to reproduce and will become extinct in the city. However, having several pollinator species, the probability of hazards removing key functions in ecological systems is significantly lower (Colding, 2007). Therefore it is essential to have a wide variety of agricultural and ecological activities within the city to increase the biodiversity (Peterson et al., 1998; Colding, 2007; Folke et al., 2010).

Lastly, waste treatment and water management should be well regulated, according to principles three and four, in order to avoid toxic pollution within the UA system. As cities are often polluted due to air polluting emissions and toxic waste from nearby industry and high density highways, soils and water can easily contain toxic materials in the city. Consequently, urban agricultural ground could become contaminated and cause significant public health issues (Brown & Jameton, 2000; Armar-Klemesu, 2000). However, the natural ability of plants to detoxify contaminated soil and air, could decrease pollution in the city. Despite this advantage, the plants will contain toxic material and will not be suited for consumption (Brown & Jameton, 2000; Armar-Klemesu, 2000).

Potential of urban agriculture in Amsterdam

Even though small initiatives aim to implement UA in Amsterdam, no significant estimate has been made for the potential in Amsterdam (Gemeente Amsterdam, 2014a). Due to a lack of this

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estimation, the feasibility of UA in Amsterdam is unknown. This section will calculate an estimation for the potential of UA on brownfield sites and in empty office buildings. Table 1 and Table 2 hold the main data used for the estimation. Data for Amsterdam in specific is most often not available, so some generalizations are made for Amsterdam based on data of The Netherlands. This should not result in inaccurate results because of the ratio of urban dwellers and rural dwellers in the Netherlands is nearly 1:1 (Erwich & Vliegen, 2010). Furthermore, it assumed that the areas on which UA can be implemented are used for fresh, fruit and vegetable, food production.

Table 1, the used data for the estimation of potential UA production and self-reliance of fresh food (Sources: Gemeente Amsterdam, 2013; Rabobank, 2012, CBS-statline, 2007)

Description Amount

Average household 1,8 persons

Total amount of residents in Amsterdam 779.808 residents Total consumption in Amsterdam 529.000.000 kg per year Total consumption of fresh food in Amsterdam 69.013.008 kg per year Average expenditure on food € 14,95 per day per resident Total Expenditure on food € 4.255.217.304,- per year Average Expenditure on fruit and vegetables € 2,- per day per resident Total expenditure on fruit and vegetables € 569.259.840,- per year

Table 2, the used data for the estimation of potential UA production and self-reliance of fresh food (Sources: Gemeente Amsterdam, 2013; CBS-statline, 2007; *Grewal & Grewal, 2010; DRO, 2014)

Description Amount

Total vacant brownfield sites 72

Total surface vacant brownfield sites 682.542 m² Total surface free office space 1.059.400 m² Average urban farming yield for fresh food 6,2 kg/m2/year*

Average intake of vegetables 73,8 kg/year/household Average intake of vegetables 41 kg/year/resident

Average intake of fruit 85,5 kg/year/household

Average intake of fruit 47,5 kg/year/resident Average intake of fresh food (fruit and vegetables) 88,5 kg/year/resident

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The brownfield sites that are available for UA are determined based on the soil pollution in Amsterdam. Figure 4 shows all the brownfield sites in Amsterdam with a soil pollution map. As indicated on the figure, some brownfield sites are polluted and not suitable for UA (Gemeente Amsterdam, n.d.(a); Gemeente Amsterdam, 2012; Gemeente Amsterdam, 2014a). Subsequently, Figure 45 shows all brownfield sites in Amsterdam without soil pollution or soil pollution with harmless concentrations. In total, 682.542 m² is available for UA on brownfield sites. Besides brownfield sites, free office space in Amsterdam is also used in the estimation. Figure 6 shows the available free office space in Amsterdam and results in a total of 1.059.400 m². Figure 5 and 6 also gives an overview on the locations where UA can be implemented. In case of the brownfield sites, they appears to be located at the city’s borders while the free office space are more spread throughout the city. Using free office spaces for UA is a new concept with high potential. The

Figure 4 (left), all brownfield sites in Amsterdam, Figure 5 (right), all brownfield sites with acceptable soil pollution concentrations. For both maps, red colours indicate polluted areas and green areas are usable for UA (Source: Gemeente Amsterdam, n.d.(a), modified)

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possible yields from indoor farming can be much higher than regular farming, and can therefore be cultivated on more expensive ground. One hectare of indoor farming can stand for 30 hectares of outdoor farming (Despommier, 2010). However, due to the size of the research, same yields have been chosen as for outdoor agriculture and in this way a minimalistic scenario has been chosen.

The potential for UA to be implemented in Amsterdam based on brownfield sites and free office space is calculated according to formula (1), (2) and (3) (see next page). It should be noted that the average yield could be potentially higher than assumed (Grewal & Grewal, 2011).

Figure 6, free office space in Amsterdam that can be used for urban agricultural activity (Source: Gemeente Amsterdam, n.d.(a), modified)

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Consequently, it appears that UA can take support 15.65% of the fresh food demand in Amsterdam and 1.83% of the total food demand in Amsterdam.

𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒 𝑓𝑜𝑟 𝑈𝐴 × 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑦𝑖𝑒𝑙𝑑 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 = 𝑡𝑜𝑡𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 (1) (682.542 𝑚2_{+ 1.059.400 𝑚}2_{) × 6,2}𝑘𝑔 𝑚2 ≅ 10.800.040,40 𝑘𝑔 𝑇𝑜𝑡𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 𝑇𝑜𝑡𝑎𝑙 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 𝑐𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 × 100 % = 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑈𝐴 𝑟𝑒𝑙𝑎𝑡𝑒𝑑 𝑡𝑜 𝑡𝑜𝑡𝑎𝑙 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 𝑓𝑜𝑜𝑑 𝑑𝑒𝑚𝑎𝑛𝑑 (2) 10.800.040,40 𝑘𝑔 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 69.013.008 𝑘𝑔 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 × 100 % ≅ 15.65 % 𝑇𝑜𝑡𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 𝑇𝑜𝑡𝑎𝑙 𝑓𝑜𝑜𝑑 𝑐𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 × 100 % = 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑈𝐴 𝑟𝑒𝑙𝑎𝑡𝑒𝑑 𝑡𝑜 𝑡𝑜𝑡𝑎𝑙 𝑓𝑜𝑜𝑑 𝑑𝑒𝑚𝑎𝑛𝑑 (3) 10.800.040,40 𝑘𝑔 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 529.000.000 𝑘𝑔 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 × 100 % ≅ 1.83 %

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24 Quantification of resilience

Based on potential of UA in Amsterdam and the relations between the theories, as described above, the resilience of the food system of Amsterdam will be quantified via several criteria, namely localisation of food production, biodiversity, soil pollution, the reliance on locally produced food, community building, and the intake of healthy and nutritious food. In the following section, these criteria are described and used with data to create an overview as displayed in table 3 in Appendix I (see page 38).

Local food production

The first criterion is based on the relation between the resilience theory with the nutrient cycle theory and green urbanism. Besides the increase of ecological resilience of the food system due to an increase of the mean rotations of a nutrient before leaving the system, a localized food production increases the social sustainability and inclusion of a city (DeAngelis, 1980; DeAngelis et al., 1989; Lehmann, 2007; Lehmann, 2010). Furthermore, people involved in community gardens appear to improve their consumption patterns to a more healthy diet (Blaine et al., 2010; Douchemin et al., 2008). As a result, the social resilience will also increase (Lehmann, 2007; Lehmann, 2010). Community markets appear to function as good indications for the amount of urban agricultural activity in the city (Mougeot & Welsh, 1999; Mougeot, 2006). The number of these markets are used as one of the quantification criteria of resilience.

In Amsterdam, there are currently five markets that sell local products. However these are not used for products produced by residents, but by local farmers. Currently the lack of markets for residential produced food, gives no incentive to residents to produce on a larger scale than for self-use only. Creating markets for residents to sell their product will stimulate residents to start or expand their urban agricultural activity because they can consume it and sell excess on the markets

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(Mougeot, 2006; City of Vancouver; 2012). There is significant potential to increase the amount of community markets and therefore the implementation of UA.

Soil pollution

The second criterion on which resilience is quantified, is soil pollution. Soil pollution causes problems for the implementation of UA in polluted cities, as mentioned in the of relation between UA and theories (see page 18-19) (Brown & Jameton, 2000; Armar-Klemesu, 2000).

Figure 4 and 5 (see page 21) show the difference in usable brownfield sites for UA in Amsterdam. Especially in the city centre are some significant areas unusable for UA, as a result of soil pollution. Still, the majority of the sites can be used for UA. It should also be noted that residents in the city centre will not be able to implement UA in their home gardens or any other space with bare ground that does not follow the criteria of the brownfield sites. By clearing the soil of pollution gives UA on bare soil more potential in the city centre.

Biodiversity

Thirdly, biodiversity appears to increase the resilience of the city’s food system. UA increases the biodiversity in the city which results in a more resilient food system (Peterson et al., 1998; Elmqvist et al., 2003; Colding, 2007; Folke et al., 2010; Lehmann, 2010). The amount of biodiversity is used as a semi-quantitative factor, based on Figure 7 to quantify the resilience of the food system.

Amsterdam has a clear policy on biodiversity within the municipality to reduce threats for species and ecosystems. For example, Amsterdam invested 12 million euros in biodiversity conservation in 2010 (IUCN, 2007; Gemeente Amsterdam, 2014a; Gemeente Amsterdam, 2014b). However, most of the biodiversity locations are located at the borders of the municipality of Amsterdam, as seen in Figure 7 indicated with dark green colours. Potential brownfield sites that could adopt UA

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as land use is also indicated on the map, with the blue dots and are scaled on size. Despite the possible adoption of UA, and therefore an increase of biodiversity, most areas are not close to the city centre. Based on this data, the implementation of UA on brownfield sites does have potential to increase the biodiversity, but less than it would if it is implemented in the city centre (Deen, 2009; Spier, 2012; Gemeente Amsterdam, 2014a). The implementation of UA in free office spaces might have potential to increase the biodiversity in the city centre, as a significant part of the free offices spaces are located in the city centre (see Figure 6). However, it is unclear whether adopting UA in office buildings increase the biodiversity, as the agricultural activity is less connected with the outside (Perkins, 1999; Mougeot, 2006).

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Figure 7, a biodiversity map with brownfield sites available for UA. Darker green colours indicate higher biodiversity levels. The spotlighted areas are not relevant for this research. Areas with biological hotspots or unique ecosystems are indicated with the red circles (Source: Gemeente Amsterdam n.d.(a); Spier, 2012, modified)

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Community building

Furthermore, the sense of community is part of the quantification of resilience. Urban gardening, especially collective gardening, can also promote this sense (Grewal & Grewal, 2011). Neighbourhoods with garden projects in Philadelphia and San Francisco observed “market reduction” in burglaries, thefts and illicit drug dealing (Malakoff, 1995) This criterion will therefore be measured by the amount of crime in Amsterdam. Neighbourhoods with a higher sense of community are more willingly to help each other and so withstand disturbances of the system. In 2011, the Afrikanerplein in the Transvaal neighbourhood in Amsterdam was turned from an inaccessible square with nuisances of liquor and drug users to a square with a community garden. The Afrikanerplein is now a place where the residents of this neighbourhood can cultivate herbs, vegetables and flowers (Gemeente Amsterdam, n.d.(b)). This transformation was part of a bigger community development programme from the municipality of Amsterdam in collaboration with various housing corporations. In total seven community gardens were created. The sense of liveability of the people rose from 6,1 in 2007 to 7,0 in 2013 (scale 1 to 10) (Wonen In Amsterdam, 2013). Because this UA project was part of a bigger community development plan, it is difficult to identify the specific benefits of UA in this projects. The introduction of more community gardens or UA in Amsterdam will plausibly create a more liveable city with a higher sense of community.

Malakoff (1995) notes that neighbourhoods with garden projects in Philadelphia and San Francisco observed “marked reductions” in burglaries, thefts, and illicit drug dealing. In addition to the liveability of the city, those indicators would plausibly drop with the introduction of UA. As seen

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in Figure 8, the current presence of crime in Amsterdam is significant. By adopting UA, there is potential to lower crime and increase the urban resilience of the food system.

Intake nutritious & healthy food

Additionally, resilience will be quantified by the intake of healthy and nutritious food. Blaine et al. (2010) showed that urban gardeners tend to focus on the production of edible items, especially vegetables. So it appears that community gardening plays an important role in the lives of participants and likely leads to permanent changes in behaviour. People who produce food in gardens tend to consume more healthy and nutritious food and consequently eat more vegetables (Blaine et al., 2010; Douchemin et al., 2008). The resilience of a city will rise when its people are more healthy and can withstand more disturbances.

Residents of The Netherlands consume 161 grams vegetables a day (Van Der Brie et al., 2012), 39 grams less than the prescribed 200 grams a day by The Netherlands Nutrition Centre Foundation Figure 8, crime rates in Amsterdam, red colours indicate high crime rates while green colours indicate low crime rates (Source: nul20.nl (2011), modified)

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(Voedingscentrum, n.d.). It is likely that this average consumption is also applicable on residents. Implementing UA in Amsterdam could lead to a higher vegetable intake (Blaine et al., 2010; Douchemin et al., 2008). This will plausibly lead to a healthier and more nutritious intake of food, that results in higher food security (Frison, Cherfas & Hodgkin, 2011). Consequently, this leads to an increase of the resilience of the food system in Amsterdam.

Self-reliance on fresh food production in Amsterdam

The last criterion is the self-reliance on food production in Amsterdam. It appears that if a city has self-reliance on food production, the food system is less dependent on the global food system and therefore has a higher resilience (Grewal & Grewal, 2011; Satterthwaite et al., 2010). Currently Amsterdam has only minor UA activity in the city, at a unmeasurable scale (Gemeente Amsterdam, 2013). It is therefore not possible to express the current UA activity in a percentage or other measure. However, Grewal & Grewal (2011, p. 3-4) introduced a method to estimate the amount of reliance on food production in a city. Based on this calculation, the potential self-reliance on fresh food in Amsterdam as a result of implementing UA on brownfield sites and in free office buildings is estimated.

Using Table 1 and Table 2 (see page 20), a percentage is made that indicates the potential self-reliance on food production in Amsterdam. Formulas (4) and (5) (see next page), calculate respectively the surface area required to support the fresh food demand per resident and the surface area required to support the fresh food demand of Amsterdam, based on an average yield for UA fresh food production (Grewal & Grewal, 2011). The potential surface area of brownfield sites (6), free office space (7) and the total of both (8) are subsequently divided with the total surface area as calculated in formula (5). This results in a potential self-reliance by brownfield sites of 6,13%, by free office space of 9,52%. In total, a potential self-reliance on fresh food production of 15,7%

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by implementing UA on brownfield sites and in free office buildings. It should be noted that this percentage could increase as the yields differ per specific crop (Grewal & Grewal, 2011). Consequently, adopting UA on brownfield sites and in free office buildings could significantly contribute in the self-reliance of fresh food and therefore may increase the resilience of the food system in Amsterdam. 𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑓𝑜𝑟 𝑓𝑟𝑒𝑠ℎ 𝑓𝑜𝑜𝑑 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑝𝑒𝑟 𝑟𝑒𝑠𝑖𝑑𝑒𝑛𝑡 = 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑖𝑛𝑡𝑎𝑘𝑒 𝑌𝑖𝑒𝑙𝑑 = 88,5 6,2 ≅ 14,27𝑚 2₍₄₎ 𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑓𝑜𝑟 𝐴𝑚𝑠𝑡𝑒𝑟𝑑𝑎𝑚 = 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑖𝑛𝑡𝑎𝑘𝑒 × 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑟𝑒𝑠𝑖𝑑𝑒𝑛𝑡𝑠 𝑌𝑖𝑒𝑙𝑑 = 88,5 × 779.808 6,2 ≅ 11.131.130𝑚 2₍₅₎ 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑏𝑟𝑜𝑤𝑛𝑓𝑖𝑒𝑙𝑑 𝑠𝑒𝑙𝑓 𝑟𝑒𝑙𝑖𝑎𝑛𝑐𝑒 𝑜𝑓 𝐴𝑚𝑠𝑡𝑒𝑟𝑑𝑎𝑚 = 𝑃𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 × 100% = 682.542 11.131.130× 100% ≅ 6,13% (6) 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑏𝑟𝑜𝑤𝑛𝑓𝑖𝑒𝑙𝑑 𝑠𝑒𝑙𝑓 𝑟𝑒𝑙𝑖𝑎𝑛𝑐𝑒 𝑜𝑓 𝐴𝑚𝑠𝑡𝑒𝑟𝑑𝑎𝑚 = 𝑃𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 × 100% = 1.059.400 11.131.130× 100% ≅ 9,52% (7) 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝑜𝑓 𝑡𝑜𝑡𝑎𝑙 𝑠𝑒𝑙𝑓 𝑟𝑒𝑙𝑖𝑎𝑛𝑐𝑒 𝑜𝑓 𝐴𝑚𝑠𝑡𝑒𝑟𝑑𝑎𝑚 = 𝑃𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 × 100% = (682.542 + 1.059.400) 11.131.130 × 100% ≅ 15,7% (8)

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32 Discussion

This research was conducted with the presumption that more data about the food system in Amsterdam was present. However, the lack of data was filled with several assumptions and generalisations in order to estimate the potential of UA in Amsterdam and the self-reliance. Moreover, the average yield used in the calculations is a simplification of the reality and this amount varied strongly in the literature. The yield that was used for the estimation was mostly based on the yield described in Grewal and Grewal (2011). The estimation can be improved by identifying the different types of crops that efficiently grow in the climate of The Netherlands, and use the average yield of these crops. Consequently, statements on the self-reliance on locally produced food can be made with more certainty. Grewal & Grewal (2011) also investigated rooftop gardening. Because of the lack of information about flat roofs in Amsterdam, this is not included in our research but could increase the potential of UA in Amsterdam.

Even though ecological and urban resilience are closely related, they cannot be seen as the same theory. Two techniques of Repko (2012) were used to conduct an new interdisciplinary interpretation of the resilience theory; organization and transformation. Even though the integration between urban and ecological resilience might be valid, care should be taken when using urban resilience. Social systems are difficult to predict and vary significantly (Holling, 2002). Therefore, the theoretical results may differ from practical outcomes of implementing UA. Subsequently, the use of the technique of transformation made the concept of resilience a quantitative variable. However, only a few aspects are taken as criteria on which the resilience is quantitated. Because of the complexity of the system, all influencing factors might not even be identified (Lehnman, 2010). Opportunities for further research are the identification of all influencing factors. Furthermore, some known factors are not taken into consideration, though they

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do influence UA. For example, waste reduction and water retention are important aspects for the quantification of urban resilience, and should therefore be also taken into account. These aspects are knowingly left out of this quantification due to the size of the research. Furthermore, more disciplinary research is needed, especially in the field of economics and politics. These insights might give a better all-round conclusion on this topic.

Even though the quantification of the research does not completely cover all aspects and is based on partially generalized data, it does gives insights on the effects on resilience when UA is implemented. Because of the lack of similar papers or interdisciplinary analysis, it is difficult to validate this research. Further research could aim to validate the outcomes of this paper.

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34 Conclusion

The first step of this paper used the integrative techniques of organization and transformation on the theories of ecological and urban resilience. It appears that both theories cannot be seen as one, but integration can be made between both theories. The concept of resource dependency is used and concludes that when an urban system is dependent on a low-resilience ecological system, urban resilience will decrease. It is therefore essential that both ecological and urban resilience improvements should be made if it is aimed to increase the resilience of a food system.

Subsequently, relations are made between UA and the theories given from the three disciplines, Earth Science, Human Geography and Spatial Planning. These relations are used in the formulation of the criteria on which resilience of the food system is quantified.

The second step of the process calculates an estimation of the potential for UA in Amsterdam if it is implemented on brownfield sites and in free office spaces for fresh food production (fruit and vegetables). It appears that UA on brownfield sites and in free office spaces can meet 15.65% of the fresh food demand in Amsterdam which is 1.83% of the total food demand in Amsterdam. This is quite significant as brownfield and free office spaces are only a part of the possible implementation locations for UA. For example, there is potential to also implement it on rooftops and in private gardens. Further research should estimate the potential for these areas.

The third step of the process is the quantification of the current level of resilience of the food system in Amsterdam. Based on the relations between the disciplinary theories, integrated urban and ecological resilience and UA, six criteria are formulated, namely localisation of food production, soil pollution, biodiversity, community building, and the intake of healthy and

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nutritious food and the reliance on locally produced food. An overview of the results of the quantification of resilience is displayed in Table 3.

The last step includes an estimation of the change of resilience of the food system of Amsterdam as a result of the implementation of UA on brownfield sites and free office space for fresh food. This is achieved by combining the estimation for potential UA in Amsterdam with the criteria on which resilience of the food system is based. These results are also displayed in Table 3.

The first criterion, local food production, is currently not applicable on Amsterdam. It is measured by the number of community markets where residents can sell their produced food. Currently, Amsterdam has five markets for local farmers but these are not used for residential produced food. Creating these markets increases the potential for UA.

The second criterion is soil pollution and it appears that the city centre of Amsterdam is strongly polluted. This makes the implication of UA on bare ground more difficult. Therefore the soil pollution should be cleared in order to increase the potential for UA.

The third criterion is based on the amount of biodiversity, used in a semi quantitative order. Biodiversity is high at city borders, though lacks in the city centre. Because of the soil pollution, UA is harder to adopt in the city centre and cannot increase the biodiversity at this location. If biodiversity increase, ecosystem services can support each other which increases both ecological and urban resilience. Consequently, this has potential to increase the resilience of the food system when the problems with soil pollution are solved.

Community building is the fourth criterion on which resilience in quantified. Crime rates appear to be good indications for community building and UA has a positive influence on reducing crime.

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Currently Amsterdam has significant crime rates, but the implementation of UA could strongly decrease these rates.

Subsequently, intake nutritious and healthy food is the fifth criterion and currently the residents of Amsterdam eat too little vegetables a day, namely 161 grams instead of 200 grams. UA appears to increase the awareness of residents to eat more healthy and nutritious, so UA has potential to increase the intake of nutritious and healthy food.

Lastly, the self-reliance on fresh food production in Amsterdam is estimated. Currently the fresh food production is at an unmeasurably small scale. However, the estimated potential of self-reliance on fresh food production in Amsterdam after the implementation of UA on brownfield sites and in free office space is 15.7%. It should be noted that this is the self-reliance for the fresh food sector only, not the total food sector. Higher self-reliance appears to increase the resilience of the food system, and therefore UA has high potential.

Comparing the results of the current state of resilience of the food system and the potential change of resilience of the food system, indicates that the resilience of the food system could increase as a result of the implementation of UA. The current state of the food system of Amsterdam has much potential for improvement and UA appears to offer benefits that could help in the improvement of the food system and reinforcement of the resilience of the food system. Consequently, the answer to the main research question, how can urban agriculture contribute to a more resilient food system in Amsterdam, is that urban agriculture can improve the urban and ecological resilience of the food system in Amsterdam when it is implemented on brownfield areas and free office spaces. On basis of these results, it is recommended for the municipality of Amsterdam to adopt UA on at least suitable brownfield sites and free office spaces. However, measures should be taken such as

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removal of soil pollution and creating of community markets. For further research, we recommend to identify possible factors that influence the resilience of the food system of cities and uses these outcomes to create a more complete analysis. Furthermore, similar interdisciplinary research should be executed for other cities to gain insights on the validity of this paper and effects of UA on resilience.

Because of the lack of similar research, it is difficult to generalize the outcomes of this paper to a broader perspective. However, Amsterdam can be seen as an average city, as described in the introduction (see page 3-4), and therefore the methodological framework used in this paper might be applicable to other cities as well. Again, further research should verify the framework.

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Appendix I

Table 3, summary of the quantification of resilience of the food system of Amsterdam

Indicator Measured unit Amount of

influence

Negative or positive influence

Current state Potential when implementing UA

Local food production

Community markets

High Positive Five markets for local farmers

More markets for products produced by residents Soil pollution Soil pollution High Negative See Figure 4 & 5 City centre pollution causes

implementation on ground level to be more difficult

Biodiversity Biodiversity High Positive See Figure 7 Biodiversity in the city centre will only slightly increase when the potential UA grounds are used Community

building

Crime & drug dealing

Medium Positive See Figure 8 UA could increase resilience as communities become closer Intake of

healthy & nutritious food

Vegetable intake

Low Positive Insufficient; vegetable intake is too low

UA has potential to increase the intake of healthy and nutritious food Self-reliance

on food

Percentage of self-reliance on food

High Positive Unmeasurably small A potential to become 15,7% self-reliant in fresh food production

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The taste of resilience Interdisciplinary project on the effects of urban agriculture on the resilience of the food system of Amsterdam – The Netherlands

University of Amsterdam