Limiting Food Waste Via Grassroots Initiatives As a Potential for Climate Change Mitigation: a Systematic Review

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TOPICAL REVIEW • OPEN ACCESS Limiting food waste via grassroots initiatives as a potential for climate change mitigation: a systematic review

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Topical Review Limiting food waste via grassroots initiatives as a potential for OPENACCESS climate change mitigation: a systematic review RECEIVED 3 January 2019 Nikravech Mariam1, Kwan Valerie1, Dobernig Karin2,∗, Wilhelm-Rechmann Angelika1 and Langen Nina1 REVISED 1 22 June 2020 Department of Education for Sustainable Nutrition and Food Science, Institute of Vocational Education and Work Studies, Technische Universität Berlin, Berlin, Germany ACCEPTEDFORPUBLICATION 2 Institute for Ecological Economics, WU Vienna University of Economics and Business, Vienna, Austria 6 July 2020 ∗ Author to whom any correspondence should be addressed PUBLISHED 16 December 2020 E-mail: [email protected]

Keywords: systematic review, food waste, climate change, mitigation, collective action, grassroots Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Abstract Any further distribution An estimated 30%–50% of food produced for human consumption is lost or wasted each year. of this work must maintain attribution to These global food loss and waste (FLW) annually generate 4.4 Gt CO2-eq, or about 8% of total the author(s) and the title of the work, journal anthropogenic greenhouse gas (GHG) emissions, and thus present a still underestimated driver of citation and DOI. climate change. To date, little is known about grassroots initiatives dedicated to reducing and preventing FLW and their actual potential to prevent FLW and thus contribution to mitigate GHG emissions. This paper presents a systematic review that examined the peer-reviewed evidence on grassroots initiatives’ potential to limit food waste and GHG emissions. We found 15 relevant studies which represent a small but recent and growing interest in the topic. The findings of the studies are mostly of a qualitative nature, exploring the initiatives’ organizational structure, goals and available resources. This systematic review highlights a pressing need for further research and impact measurement to better assess the role of grassroots initiatives in FLW reduction and climate change mitigation. It raises main directions for future research.

1. Background et al 2020). Thus, reducing FLW is indisputably crucial to mitigating climate change and environmental Globally about 30%–50% of food produced for degradation. human consumption is wasted each year (Gustavs- Scholarly discussions on measures to reduce and son et al 2011). For Europe, Stenmarck et al (2016) prevent FLW have so far mostly focused on either estimated that around 20% of the food produced government-led projects and policies, or on initiat- is wasted whereby individuals in developed coun- ives in the industrial food and third sector (such tries waste between 10% and 50% of the food they as the hospitality sector, commercial and collect- buy. Apart from the economic, social and ethical ive catering, wholesalers, retailers). Also, a top-down concerns, global food loss and waste (FLW) bears approach has been privileged as a mode of action high environmental costs, mainly because energy and for cutting the carbon footprint of the food sec- resources invested in food production are spent in tor (Bows 2012). Regulatory policy is important, yet vain. Indeed, global FLW (from food production, ‘voluntary behavioural change on the individual and land use change, and disposal) generate 4.4Gt CO2-eq household-level is an equally integral part of the annually, or about 8% of total anthropogenic GHG transition towards a comprehensive foodprint reduc- emissions (FAO 2011, 2013, 2014, EC and JRC/PBL tion’ (Kim 2017, p. 367). Bottom-up grassroots initi- 2012, Crippa et al 2018). From the per capita per- atives dedicated to reducing and preventing FLW have spective, the average mitigation potential of reducing received less attention, albeit they often follow innov- avoidable FLW is 0.3 t CO2-eq—considerably higher ative approaches and strategies and thus might be a than the average mitigation potential of managing powerful actor in FLW reduction and thus climate unavoidable FLW at 0.03 t CO2-eq/cap (Ivanova change mitigation.

1.1. Grassroots initiatives and food waste their role in reducing GHG emissions and mitigat- Forged as a sociological tool to analyse the spread ing climate change. While grassroots initiatives or sus- of new forms of collective action, particularly in the tainability transitions literature have been the topic of context of dictatorships in Latin America (Hirschman systematic reviews (Hossain 2016; Sengers et al 2019), 1984), the concept of grassroots activism has also been these have not mapped grassroots initiatives accord- used to reflect on new forms of bottom-up environ- ing to their potential in tackling climate change via mental activism in the 1990s and 2000s (Cable and food waste reduction. To date, systematic reviews on Benson 1993, Almeida and Brewster Stearns 1998, food waste have compiled estimates of FLW (van der Mihaylov and Perkins 2015). Here, grassroots act- Werf and Gilliland 2017) and categorized the factors ivism encompassed forms of collective action initi- that impede or foster the generation of food waste ated by communities at the local level as a means of at the household-level (Schanes et al 2018, Stangher- social inclusion. Grassroots initiatives are defined by lin and de Barcellos 2018). Other reviews have a Grabs et al (2016, p. 100) as social activism ‘includ- specific geographical and/or sectoral focus such as ing any type of collaborative social undertaking that food waste drivers in the Arab world, in Brazilian is organized at the local community level, has a high ‘Food and Nutrition Units’, or food waste occurring degree of participatory decision-making and flat hier- in the national school lunch program in the United archies’. They are clearly distinguished from profit- Kingdom (Shanks et al 2017, Abiad and Meho 2018, oriented organizations as they ‘tend to operate in Ferigollo and Busato 2018). civil society arenas and involve committed activists’ The objectives of this systematic review are three- (Seyfang and Smith 2007, p. 585) as well as employ fold: First, it attempts to map grassroots initiatives alternative worldviews and system of values (Mar- dedicated to food waste reduction and prevention tin et al 2015, van Oers et al 2018). Importantly, along their stated objectives, the actors involved, and ‘these groups constitute a nexus between individual their broader network. Second, it compiles the out- motivation and collective action’ (Grabs et al 2016, comes of academic studies which have measured the p. 100). Often conceptualized as a new social move- effectiveness of grassroots initiatives to reduce or ment, grassroot initiatives aim to promote socio- recover FLW as well as reduce GHG emissions. Third, technological changes to address environmental and it categorizes the key success factors for grassroots social problems (van Oers et al 2018). initiatives to identify potential ‘bottom-up’ levers for While the impacts and benefits of grassroots ini- food waste reduction and prevention originating in tiatives unfold primarily locally (Seyfang and Smith civil society to complement ‘top-down’ approaches. 2007, Ornetzeder and Rohracher 2013, Smith et al 2014, van Oers et al 2018), strategies are commonly 2. Methods devised to scale-up these impacts, such as open communication, inclusion of stakeholders, and enrol- We conducted a systematic review of existing aca- ment of public, private and non-governmental act- demic research on grassroots initiatives dedicated to ors (Smith et al 2014). Grassroots initiatives appear reducing food waste. To ensure that the review is as innovative players to convey the claims of environ- systematic and replicable, we followed the Preferred mental justice activism, which emerged as a form of Reporting Items for Systematic Reviews and Meta- post-industrial collective action (Mihaylov and Per- Analyses (PRISMA) quality guidelines (Moher et al kins 2015) analysed within the New Social Movement 2009, 2015) which provide an evidence-based min- theory (Melucci 1980). Environmental grassroots imum set of items for reporting. initiatives differentiate themselves from traditional To ensure the focus of our review on grassroots environmental movements, in shifting the focus away initiatives, we excluded literature according to the cri- from political institutions towards a reshaping of teria outlined in table 2. These criteria were used at everyday consumption practices (Haenfler et al 2012, screening and at eligibility stages. Dobernig and Stagl 2015, Laamanen et al 2015, Cam- pos and Zapata 2017). Grassroots initiatives operating in the area of sus- 2.1. Sampling and search strategy tainability have embraced food as a key realm for Relevant articles were located based on the object- change, along with mobility or energy. They pursue a ive of gathering peer-reviewed evidence of the role of variety of activities: food growing and sharing (Davies grassroots initiatives in reducing food waste to mit- 2014, Rut and Davies 2018), food rescuing (Reynolds igate climate change. The search focused on peer- et al 2015), or surplus food redistribution (Midgley reviewed journal articles published between 2000 2014). However, little attention has been paid to the and 2018 in English, German and French. Grey lit- effectiveness of sharing practices to reduce food waste erature, including master’s theses, conference pro- (Morone et al 2018). ceedings and organizational reports, were excluded. This paper addresses this gap by systematic- For defining the search strategy, we defined inclu- ally reviewing the existing academic literature on sion criteria for our study along the PRISMA recom- grassroots-level initiatives around food waste and mendations (Moher et al 2015). For this, we used

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Table 1. Sampling strategy. PICOS criteria Problem Intervention Comparator Outcome Study design Grassroots initiatives for food Reported waste preven- amount of food tion or reduc- waste/GHG Food waste tion Open emissions Open Type of literat- Peer-reviewed literature ure

Languages English, French, German

Timespan 2000–2018

Table 2. Exclusion criteria. Exclusion of peer-reviewed studies which:

(a) did not have food loss or waste as main problem (b) focused on supply-side initiatives driven by retailers, producers or the local government, as well as solely on individual- and household-level initiatives (c) solely discussed behavioural determinants and attitudes for food waste (d) only quantified food waste of GHG (e) investigated grassroots initiatives that did not focus on food waste reduction (f) did not consider community-based interventions as the main level of analysis, such as meta-analyses or system analyses (used only at eligibility stage) (g) had a natural science focus (used only at screening stage) the PICOS criteria (Problem/Intervention/Compar- bibliographic databases CAIRN and INRA Sciences ator/Outcomes/Study design) as defined by Methley Sociales as well as the German-speaking database et al (2014). We considered FLW as our problem WiSo were also searched. The first five pages of the of interest and grassroots initiatives dedicated to web-based database Google Scholar were considered food waste prevention or reduction as our interven- as complementary sources of evidence. Duplicates tion. If presented, we conceptualized outcomes as the were removed within databases and between data- amount of food waste reduced and/or mitigated GHG bases (n = 135). The initial keyword search string emissions, expressed as CO2-eq. The study design was was adapted to fit each database search engine syntax kept open to include all types of research designs. (table A1, table A2). The search term list was com- Finally, due to the low retrieval rate of experimental prised of the three PICOS criteria: (i) problem, (ii) or quasi-experimental studies, there was no restric- intervention, and (iii) outcome, which were respect- tion on the comparator (see table 1). ively ‘Food waste’, ‘Grassroots’ and ‘Greenhouse Gas’ In the case that an article described food waste (table A1). The search was also run without the third reduction initiatives at the crossroads between the term, to comprehensively appraise all studies which supply-side sector, the public sector, and civil soci- investigated grassroots initiatives for food waste ety, a case-by-case approach was used to delimit the prevention. intervention as a grassroots initiative or not. The cri- The systematic search resulted in 1875 articles. All teria for inclusion as a grassroots initiative were (i) the abstracts were screened manually, of which 67% were initiative was started by a civil society actor, (ii) the screened independently by two reviewers (‘Screen- initiative began locally, (iii) the initiative was partly ing’ stage in figure 1). The reviewers decided at that or mainly based on the action of volunteers, and (iv) stage to consider the studies for full text reading or to the hierarchy of the initiative was flat. Some studies exclude them, along the previously defined exclusion investigated the structural features and impact of food criteria. At that stage, we decided to be inclusive if sharing via a pilot approach or meta-analysis. These uncertain. When no agreement was reached (n = 5), did not provide sufficient insight into the individual a third author made the final decision. The main grassroots initiatives. exclusion reasons during the screening phase are also depicted in figure 1. After the title and abstract screening, n = 127 2.2. Data collection articles remained. Additional records were identified The systematic literature search was conducted via through reference checking and snowballing (n = 1) a word search run in the titles, abstracts and and included if they had not shown up in our pre- text of items in the bibliographic databases Web vious searches. In the next step, the pool of 127 art- of Sciences (Social Sciences Indexes only), Science icles was extracted for full text reading and a fur- Direct, Scopus and AGRIS. The French-speaking ther specification of the sample (‘Eligibility’ stage

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Figure 1. Full PRISMA flow chart including exclusion reasons by frequency. Source: Adapted from VonVille (2019) with permission. © CC BY-NC-SA 3.0. And from Moher et al (2009). CC BY 4.0. Note that the following abbreviations are used: Food loss and waste (FLW); Greenhouse gas emissions (GHG).

in figure 1). In case it was not possible to access Moreover, we discuss the resources available to grass- an article, it was reported as unavailable (n = 21). roots initiatives tackling food waste as well as the out- The full-text papers were stored manually using the comes of grassroots initiatives in terms of food waste Excel Workbooks and User Guides for Systematic reduction and climate change mitigation. The ana- Review (Vonville 2019). References were stored in lysis of the peer-reviewed articles was conducted with the reference management software Citavi (n = 106). the qualitative and mixed-method analysis software Every full text was read independently by at least MAXQDA. The coding was organized around four two researchers to ensure consistency. Exclusion cri- key categories: (i) methodologies employed in the teria were the same as above. We reported the main studies, (ii) type, goals, participants and resources of reasons for exclusion by frequency and the exclu- the grassroots initiatives studied, (iii) outcomes of the sion process in figure 1. Bibliographic information grassroots initiatives, and (iv) key success factors and such as journal, author, year of publication and challenges. country of the study were extracted. This process resulted in a final sample size of 15 peer-reviewed articles. 3. Review results

2.3. Analysis and synthesis While the number of studies investigating grassroots Given that the systematic literature search revealed initiatives to reduce and prevent food waste (accord- only a very small number of studies that quanti- ing to our research interest and the resulting inclu- fied the outcomes of grassroot initiatives (n = 9), sion criteria) has increased since 2000, especially from a quantitative analysis of the data was not justi- 2015 onwards, the overall scholarly discussion about fied. Instead, we extracted and synthesised the out- their contribution to reducing food waste and mitig- comes presented in the individual studies in the form ating climate change remains modest. Grassroots ini- of descriptive statistics. In a narrative synthesis, we tiatives were mainly studied in Australia (n = 3), the review findings from the sampled studies to discuss United Kingdom (n = 3), and the USA (n = 5); fol- the key characteristics of the studied initiatives, in lowed by New Zealand (n = 1), Sweden (n = 1), Aus- particular their goals, organizational structure as well tria (n = 1) and Singapore (n = 1) (table 3). All stud- as the profiles of people engaged in the initiatives. ies were conducted in urban areas (n = 15).

4 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ) ) ) ) 2017 ) ( 2017 2007 2017 2017 ) et al 2018 Campos and Zapata ( Sarti Caplan ( Barnard (2010) Edwards and Mercer ( Kim ( Rut and Davies ( Start time of the initiative2012 Study 2012 N/A 2000 1980s N/A 2015 Location Gothenburg (Sweden) Germany West Wales (UK) New York City (USA) Australia London (UK) Singapore Organization Food movement network/citizen- based initiative Citizen-based initiative/digital social platform Global food movement (Transition network) Global food movement Global food movement Citizen-based initiative/community gardening Citizen-based initiative/community gardening/online platform Enabling factors Development of contextualized knowledge and competences related to food waste prevention Vivacious community and critical mass of users on aplatform single Embedment into the global Transition network Embedment into the global Free- gan network Media exposure and audience’s attention Easiness of participation Alliances with smaller shops Embedment into the global Free- gan network Easing legal and regulatory framework Supportive social environment Embedment in local network Strong volunteer engagement Embedment in the local and larger food community network (informal groups, community gardening, dumpster diving) and strategic partnerships with entrepreneurs and CSOs Overview of the sampled studies and the studied grassroots initiatives. Table 3. Activities Food Rescue Parties: Cooking rescued food in social events Food Rescue free markets Popup restaurant during the Restaurant Day Festival sharers to save and re-distribute food surplus among them Con- nects volunteer foodsavers and organize rescue operations at markets and supermarkets Serves meals at affordable prices, made of local surplus food. Practice of dumpster diving for discarded food for individual consumption and other anti- consumerist practices Practice of dumpster diving for discarded food for individual consumption Local food growing Mapping of edibles in Singapore Online Plat- form for knowledge and skill- sharing about growing, healthy eating and waste reduction e Bro Gwaun ´ Name of the grassroots initiative Food Rescue FoodSharing Platform Connects a community of food- Transition Community Caf Freegans Dumpster divers Community gardens Local food growing The Collective Priority Environmental priority

5 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ), ) ) ) et al et al 2017 2017 ( 2007 et al et al ) ) ) ) Reynolds ) ) 2015 ( et al 2016 2016 2015 2014 2015 2013 Sönmez ( Mirosa ( Warshawsky ( Lindberg ( et al Schneider ( Edwards and Mercer ( Lee Reynolds ( Walia and Sanders ( 2012 2005 2010 Start time of the initiative Study 1980s N/A N/A Early 1980s 1980s New Zealand Los Angeles (USA) 2009 Victoria, Tasmania, Queensland, and New South Wales (Australia) Austria Location Australia Boston metropol- itan area New York State (USA) Australia New-York City (USA) North Car- olina (USA) Indi- anapolis (USA) Food rescue social enterprise Food rescue social enterprise Food rescue social enterprise Food rescue social enterprise Organization Global food movement Food rescue social enterprise Food rescue social enterprise Food rescue social enterprise Continue Table 3. Access to fresh surplus food Positive reputation of saving and distributing nutritious fresh food Network and collaboration for increased access to food wastes supply and social reach Diversification of funding sources Successful framing of food waste as an issue Positive reputation of saving and distributing nutritious fresh food Access to fresh surplus food Abund- ant pool of volunteers Volunteers’ engagement EU regulatory frameworks Enabling factors Embedment into the global Freegan network Easing legal framework Scheduling capacity, amount and eagerness of volunteers Financial donations Extensive network of food waste suppliers Early local scale up Hol- istic approach to the food recovery process Collection and redistribution of donated food surplus Collection from wholesales and farmer markets and redistribution of recovered food to local CSOs backyard harvesting program Collection and redistribution of surplus fresh food Community capacity building in food skills and nutrition Advocacy of donated food from companies and supermarkets at the Austrian Red Cross Activities Collection of surplus food from markets to cook and serve toon people the street Collection and redistribution of donated food Culinary job training program for disadvantaged adults Practice of gleaning from farmers and offering of fresh food toassistance food recipients Collection and redistribution of donated food FoodShare Food Forward SecondBite Team Österreich Tafel Collection, sorting and distribution Name of the grassroots initiative Food Not Bombs City Harvest Inter- Faith Food Shuttle Second Helpings Food Bank of the Southern Tier (FBST)’s gleaning program FareShare OzHarvest FoodBank Priority Social priority

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3.1. Analytical scope but employ content analysis (n = 3) (Schneider 3.1.1. Research objectives of reviewed studies 2013, Sarti et al 2017, Walia and Sanders 2017) The research objectives of the studies we reviewed and impact quantification methods (n = 3) (Reyn- can broadly be grouped into two complementary olds et al 2015, Sönmez et al 2016, Lee et al 2017). foci: The first group of studies explore grassroots Finally, one study (n = 1) is based on a cross-sectional initiatives to describe the collective and individual web-survey design among gardeners in community motivations and practices of reducing food waste. gardens and food growing organizations (Kim More specifically, studies conceptualize freegan col- 2017). lective dumpster dives as acts of political street theatre (Barnard 2011); describe how food gleaners in Aus- 3.1.3. Type of data collected tralian cities identify with freeganism (Edwards and Within their research designs, most studies (n = 8) Mercer 2007); discuss the place of civil society organ- collect qualitative data via in-depth semi-structured izations (CSOs) in urban food governance and debate interviews with stakeholders such as food donors, fin- grassroots CSOs in the context of food waste reduc- ancial donors, recipient agencies (Mirosa et al 2016); tion (Warshawsky 2015); deconstruct popular views government administrators, formal food grocers, of food surplus and food aid (Caplan 2017); describe farmers market sellers, food recovery CSO managers the workings of an Australian food rescue organ- (Warshawsky 2015); food consumers (Warshawsky ization (Lindberg et al 2014); develop a theoretical 2015), volunteers (Edwards and Mercer 2007, Barn- framework on citizen-driven initiatives for waste pre- ard 2011, Lindberg et al 2014, Warshawsky 2015, vention to grasp their diffusion and contribution to Mirosa et al 2016, Campos and Zapata 2017, Caplan social change (Campos and Zapata 2017); and doc- 2017, Kim 2017, Rut and Davies 2018) and paid staff ument ICT-mediated shared food growing (Rut and members. Interestingly, recipients’ perspectives are Davies 2018). not reflected in the studies unless they are volunteers The second broad group of studies investigates or paid staff of the respective initiative. (n = 3) use the outcomes of grassroots initiatives in reducing ethnographic and participant observations (Edwards or preventing food waste, such as the social value and Mercer 2007, Barnard 2011, Warshawsky 2015). of food rescue enterprises for the stakeholders and Two studies (n = 2) collect data via web-based surveys the communities (Mirosa et al 2016); how com- with 79 volunteers and 48 community garden parti- munity gardening improves daily food consump- cipants respectively (Mirosa et al 2016, Kim 2017). tion and waste management practices and thereby Finally, six studies (n = 6) are mainly based on sec- shrinks the carbon foodprint (Kim 2017); the eco- ondary data, such as documents and internet material nomic and environmental impact of food rescue (Schneider 2013), online platforms (Sarti et al 2017) operations from charities and NGOs (Reynolds et al and organizations’ administrative data (Reynolds et al 2015, Sönmez et al 2016, Lee et al 2017, Walia and 2015, Sönmez et al 2016, Lee et al 2017, Walia and Sanders 2017); the comparative potential of online Sanders 2017). food sharing platforms to help prevent food waste (Sarti et al 2017); and the impact of food donation on ecology, economy and society (Schneider 3.2. Main characteristics of the academically 2013). investigated grassroots initiatives In the following sections we discuss the grass- 3.1.2. Design of the reviewed studies roots initiatives in our sample with regards to their To address these research objectives, our reviewed goals, organizational structure and participants. Sub- studies employed different research methodologies: sequently, we categorize the resources which the ini- The case study approach is adopted in four studies tiatives possess to work towards their goals. (n = 4) with either one or several grassroots initiatives as the unit(s) of analysis. The specific cases selec- 3.2.1. Overall objectives/goals/missions ted for the studies are FoodShare, an urban social All studied grassroots initiatives embrace the goal enterprise specialized in food redistribution (Mirosa of reducing food waste with a focus on human et al 2016); the local Food Rescue CSO Food For- consumption which is in line with the food waste ward (Warshawsky 2015); transition caf´es (Caplan hierarchy (Papargyropoulou et al 2014) pictured 2017); citizen-based food waste prevention initiat- in figure 2. The food waste hierarchy provides a ives (Campos and Zapata 2017); and a community framework of the available options for the pre- food growing initiative (Rut and Davies 2018). Four vention and management of food waste and sorts studies (n = 4) take an ethnographic approach to them by desirability. While some initiatives expli- analyse food gleaners (Edwards and Mercer 2007), citly prioritise the prevention of avoidable food freegans (Barnard 2011), a food rescue social enter- waste (and thus addressed the first priority of prise (Lindberg et al 2014) and a shared food grow- the food recovery hierarchy), others work primar- ing initiative (Rut and Davies 2018). Six (n = 6) ily on the re-distribution and re-use of food studies do not mention a specific research design surplus.

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Grassroots initiatives focusing on food waste pre- redistributing it to people in need, addressing the vention (n = 5) offer networks and tools to save second priority in the food waste hierarchy (n = 8). surplus food and use it for the own consumption The common concept of food redistribution has (Edwards and Mercer 2007, Barnard 2011, Campos many names: food rescue (Lindberg et al 2014, Reyn- and Zapata 2017, Sarti et al 2017) or share the food olds et al 2015, Warshawsky 2015), food rescue social surplus within the community (Caplan 2017, Sarti enterprise (Mirosa et al 2016, Walia and Sanders et al 2017). Some initiatives critically question con- 2017), food rescue CSO (Warshawsky 2015), food sumption practices (Barnard 2011), promote a radical redistribution from gleaning (Edwards and Mercer anti-capitalist ideology (Edwards and Mercer 2007, 2007, Lee et al 2017) or food donation (Schneider Barnard 2011), and challenge middle-class taboos 2013). At the nexus of food security and food waste around food waste (Campos and Zapata 2017). These (Mirosa et al 2016, Lee et al 2017), these initiat- initiatives promote awareness of food waste gener- ives re-use surplus food to reduce hunger and food ation and demonstrate how tasty and safe ‘waste inequality. food’ is (Barnard 2011, Campos and Zapata 2017). Complementary to this, some grassroots initiatives (n = 2) promote urban farming (Rut and Davies 3.2.2. The organizational structure of the initiatives 2018) and community gardening (Kim 2017) which Grassroots initiatives take complex institutional have the potential to limit food waste. These initi- forms and have different organizational structures atives offer shared open spaces managed and oper- (table 2). While having in common a strong volun- ated by members of the local community for multiple teer basis (Reynolds et al 2015), they differ greatly in purposes such as vegetable growing (Kim 2017)1,2 or size, number of volunteers, amount and volume of knowledge and skills sharing about growing, eating food saved, degree of professionalization, as well as healthy and reducing waste (Rut and Davies 2018). funding and recognition. = They promote another model of food consumption Three studies (n 3) focus on loosely formal- and production with the goal of reducing the carbon ized, connected initiatives belonging to a broader, foodprint, notably via the reduction of food waste global food movement which prioritize individual (Kim 2017),3 and fostering well-being (‘Grow food, and community-directed actions (Barnard 2011). cook well, eat well, live well’, Rut and Davies 2018, The Food Gleaners and Dumpster Divers are respect- p. 282). ively embedded in the Food Not Bombs group and Grassroots initiatives emphasizing food redistri- the Freegan movement, both of which are global in bution seek to divert edible food from the bin by reach (Edwards and Mercer 2007, Barnard 2011). The Community Transition Caf´e Bro Gwaun described in (Caplan 2017) recycles local surplus food to serve meals at affordable prices and is part of the Trans- 1 To facilitate the reading, we refer in the text to the authors of the ition Network. These three grassroots food move- sampled reviewed studies. Secondary citations are given as foot- note. ments for food waste reduction have at least two 2 Holland (2004) cited in Kim (2017) p. 365. aspects in common: a flat hierarchy and a high level 3 Abrams (2014) cited in Kim (2017), p. 366. of engagement of activists who are the backbone of

8 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al the initiatives. Such food movements are analysed Campos and Zapata 2017) also elicits a motivation to by the New Social Movements literature as a reper- engage in movements like freeganism, as this allows toire of practices encompassing more than only food, to express political and moral concerns while enga- although dumpster diving is the most central, i.e. get- ging locally in freegan practices (Edwards and Mer- ting food from the trash and eating it (Barnard 2011). cer 2007, Barnard 2011, Campos and Zapata 2017). Four studies (n = 4) discuss citizen-led initiat- The adoption of other activities associated with free- ives (Campos and Zapata 2017, Kim 2017, Sarti et al ganism such as squatting, scavenging, community 2017, Rut and Davies 2018) that encompass informal living, cycling, and second-hand shopping are fur- and self-organized community groups. Conceptual- ther factors which support and sustain engagement ized in Campos and Zapata (2017, p. 17) they ‘share in food waste prevention practices such as dumpster the capacity to mobilize people and get them to diving or food gleaning (Edwards and Mercer 2007, work, regardless of whether volunteers, participants, Barnard 2011). The development of contextualized and employees shared the values and rationales of knowledge and competences (Barnard 2011, Mirosa the organizers’. One example are social not-for-profit et al 2016, Rut and Davies 2018) needed ‘to trans- platforms, which facilitate the sharing and exchange form unwanted resources into commons’ (Campos of food surplus in a peer-to-peer approach. These are and Zapata 2017, p. 1069), as well as the knowledge flexible and free of charge but depend on the work of ‘about what works in a locality and what matters to voluntary food savers (Sarti et al 2017). local people’ (Seyfang and Smith 2007, p. 593–4 cited CSOs and social enterprises are studied in nearly in Campos and Zapata 2017) are also motivational half of the reviewed articles (n = 7). These are factors. non-governmental not-for-profit entities that ori- Participants of food waste grassroots initiatives ginated in civil society. Because of paid staff and commonly pursue alternative diets, often reflect- management, they are often able to secure and ing the organic food, freegan or vegan discourse provide advocacy and other services (Warshawsky (Edwards and Mercer 2007). According to Edwards 2015). Although they present professionally-led vol- and Mercer (2007), demand for ethically acceptable untary organizations, they have flexible structures products (i.e. acceptable producer history and labour and are attentive to local communities and non- conditions, absence of ‘chemicals, pesticides, indus- governmental funding (Warshawsky 2015). Examples trial waste-ridden food’ (Edwards and Mercer 2007, of social enterprises are: Food Forward (Warshawsky p. 286) and animal cruelty) is stronger than consid- 2015), the Social Enterprise (Mirosa et al 2016), erations like quality and quantity of food or ease of SecondBite (Lindberg et al 2014, Reynolds et al 2015), access. the Inter-Faith Food Shuttle and Second Helpings Reducing food waste for environment benefits (Walia and Sanders 2017), Team Österreich Tafel and to fight climate change is also a reason for volun- (Schneider 2013) and the Food Bank of the South- teers to invest time and effort in grassroots initiat- ern Tier (FBST) (Sönmez et al 2016, Lee et al 2017), ives (Edwards and Mercer 2007, Lindberg et al 2014). which provide food stores and farmers with food sur- According to (Caplan 2017), the goal is primar- plus and food waste collection services or gleaning ily environmental and consists of developing ‘com- operations. munity sustainability and resilience’, while feeding poorer people is seen as incidental. Other authors 3.2.3. Participants in the initiatives and motivation point to the fight against ‘food poverty’ as a main There is relatively little information provided driver for engagement (Lindberg et al 2014) or about the socio-demographic profile of the people emphasized further factors such as altruism, a com- who initiate and engage in grassroots food waste mon praxis and shared ideas (Edwards and Mercer initiatives. Edwards and Mercer (2007) describe 2007, Barnard 2011); a sense of community involve- dumpster divers and volunteers in Food Not ment and community empowerment (Edwards and Bombs as predominantly male, mid-20s, well- Mercer 2007, Lindberg et al 2014, Mirosa et al 2016, educated and middle-class. Kim (2017) observes Rut and Davies 2018), friendship and socialising a majority of female practitioners in community (Edwards and Mercer 2007, Mirosa et al 2016), or gardens. emotional benefits gained when participants make Several studies look at the motivations of the par- new connections with others (Mirosa et al 2016). ticipants, volunteers or activists of the initiatives for Spiritual motivation is also a factor to engage in food engaging in collective action to reduce food waste waste prevention and rescue (Barnard 2011, Campos or redistribute food surplus. Awareness of global and Zapata 2017). food production systems (Edwards and Mercer 2007) and strong ideological beliefs, such as dropping out 3.2.4. Availability of resources of capitalism (Edwards and Mercer 2007, Barnard Jenkins (1983) provides Resource the Mobilisation 2011), are critical motivation factors. Preference for Theory framework of social movements which allows a common use of natural and material resources the systematic categorization of the resources which instead of owning and consuming (Barnard 2011, social movements possess to secure control and

9 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al increase their potential to act towards their goals. We cultural, taste) with dignity poses a wider problem in employ this framework to review the resources ana- the food re-distribution sector, in addition to food lysed in the reviewed studies. safety aspects. In another study, Edwards and Mer- cer (2007) analyse how within the Freegan move- 3.3. Volunteer efforts ment, the redistribution of (any kind) of rescued food Many studies emphasize the role of volunteers in conflicts with the issue of maintaining a strict vegan grassroots initiatives. Indeed, analysed as low-budget diet. and labour- and time-intensive, grassroot initiatives Food rescued from the trash and handled by the rely heavily on a strong basis of volunteers (Reyn- participants emanates mostly from the private food olds et al 2015, Campos and Zapata 2017). Lee et al sector, in particular the tertiary (n = 8) and to a lesser (2017) and Sönmez et al (2016) relate the success of extent the secondary sector, including the hospitality gleaning operations to the supply of volunteer glean- sector (Reynolds et al 2015, Walia and Sanders 2017). ers, their eagerness to attend an operation, and the Food surplus is collected from food wholesalers scheduling capacity of the organization. Most grass- (Caplan 2017) and retailers (Barnard 2010, War- roots initiatives engaging in food waste redistribution shawsky 2015, Mirosa et al 2016, Campos and Zapata relied either exclusively (Barnard 2011, Schneider 2017, Caplan 2017, Walia and Sanders 2017) which 2013, Campos and Zapata 2017, Sarti et al 2017, Rut include supermarkets (Barnard 2010, Edwards and and Davies 2018) or primarily (Edwards and Mercer Mercer 2007, Mirosa et al 2016, Caplan 2017), small 2007, Mirosa et al 2016, Lee et al 2017) on a volun- local stores (Reynolds et al 2015) and organic market teer or activist basis. Volunteers provide time, pro- stallholders (Edwards and Mercer 2007, Warshawsky fessional skills and knowledge, fuel and cars (Mirosa 2015). According to Edwards and Mercer (2007) free- et al 2016), and engage in physical, complex and tir- gans privilege small local independent stores since ing work collecting, sorting, and redistributing food they tend to be more resource-oriented than big- (Warshawsky 2015). ger stores, are more likely to consider a community- benefit orientation, and thus are more prone to 3.4. Types of food (waste) reduced cooperation. Besides, small stores provide gourmet Interestingly, the reviewed studies provide only lim- or health-related produce and help support local ited information on the type of food rescued by the sustainable food production (Edwards and Mercer grassroots initiatives, thus eluding the question of the 2007). Nonetheless, the choice to dumpster dive in big trade-offs between food-related resources and effort supermarket chains over smaller independent stores mobilization. The studied grassroots initiatives res- is perceived as more effective (Barnard 2010) and cue any type of edible, not spoiled food (Barnard allows for a symbolic power reversal against capitalist 2011) about to be wasted, both fresh and long-life natural resource and human exploitation (Edwards (Caplan 2017), approaching or past its expiry date and Mercer 2007). (Campos and Zapata 2017) or use-by date (Reynolds Two studies (n = 2) discuss initiatives that take et al 2015), or surplus to the requirements of events food donations from the food manufacturing sector (Reynolds et al 2015). Schneider (2013) distinguishes (Schneider 2013, Reynolds et al 2015). Two studies three categories, namely bread and pastry, fruits and (n = 2) analyse food waste prevention through glean- vegetables, and dairy products without indicating a ing at farm level (Lee et al 2017, Walia and Sanders priority in food rescue choice. The nature and quant- 2017). In Sarti et al (2017), the food surplus dis- ity of the food supply may vary seasonally and thus cussed emanates from private consumers. The pub- demand different degrees of effort and capacity from lic sector barely features in the scholarly discussion the grassroots organizations (Lee et al 2017). For of sectors; Campos and Zapata (2017) highlight the the estimation of the grassroots initiatives’ contri- failure to extend the initiative to food handled by bution to the reduction of GHG emissions, the dif- municipalities. ferentiation between the product groups would be essential. Lindberg et al (2014) and Walia and Sanders 3.5. Financial resources (2017) discuss the choice of SecondBite and the Inter- The success of grassroots initiatives also depends Faith Food Shuttle to prioritize healthy foods, mostly highly on their capacity to secure financial resources fruits and vegetables, to redistribute to people in need. (Mirosa et al 2016, Campos and Zapata 2017), such Mirosa et al (2016) discuss how a focus on fresh as governmental financial support from the local city food may enhance the social organization’s reputa- council (Mirosa et al 2016). Yet, local and global eco- tion and increase their reach within the community. nomic crises have led to a withdrawal of government Yet, the random nature of food rescued and its incon- support and necessitated mixed funding streams from sistency with an overall healthy diet creates challenges foundations, individuals and corporate philanthropic in managing the gaps between supply of rescued food fundraising (Caplan 2017). This can also be supple- and demand (Reynolds et al 2015). Moreover, the mented with income earned as a social enterprise complexity of meeting users’ needs (i.e. religious, (Warshawsky 2015).

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3.6. Legal and regulatory framework businesses donated food benevolently to increase Some studies discuss how national and local regulat- community involvement. On the other hand, War- ory frameworks facilitate food rescue and food waste shawsky (2015) emphasizes the barriers for private prevention (Edwards and Mercer 2007, Schneider wholesalers and retailers to partner with food rescue 2013, Mirosa et al 2016). National food safety regu- organizations such as the goals of profit maximiz- lation is a strong obstacle to the rescue and donation ation and brand leverage through marketing. Barn- of food, particularly when originating from ‘waste’, ard (2011) analyses the ambiguous relationship that due to the expected safety risk. In the US, the Good freegans entertain with retail stores: while contra- Samaritan Law 2002/Bill Emerson Good Samaritan dicting the capitalist logic of supermarkets, freegans, Food Donation Act ‘protects donors from liability dumpster divers and gleaners need to ensure access to when donating to a non-profit organization as well as the food surplus in the dumpsters, and thus need to from civil and criminal liability if a product, donated secure a positive or neutral stance towards the retail- in good faith, later causes harm to one of the needy ers. Reynolds et al (2015) note that many of the ser- beneficiaries’ (Schneider 2013, p. 761). Similarly, in vices provided by volunteer-driven and charity-based New Zealand, the Food Act 2014 provides ‘Immunity grassroots initiatives cannot be offered by the private of Food Donors’ to donate the edible surplus food sector without philanthropic or government support. with limited legal risk (Mirosa et al 2016). Sarti et al The local government is also a central actor that grass- (2017) note the lack of clear food safety regulations roots initiatives seek collaboration with, mostly to surrounding food sharing and donation practices access financial support, but also to ensure ‘laissez- which hamper the wider diffusion of food sharing ini- faire’ (Campos and Zapata 2017, Kim 2017, Rut and tiatives. The local waste management system can also Davies 2018). Finally, studies have examined how cer- set constraints on the access to food which has already tain grassroots initiatives are embedded in an interna- landed in the bin. For example, in the New York City tional food movement network from which they can waste management system, dumpster diving is con- seek support. The food movement networks oper- sidered as theft (Barnard 2011). ate at multiple levels: neighbourhood, municipal, regional, national and international (Campos and 3.7. Media coverage Zapata 2017) and allow for networking, exchange Grassroots initiatives for food waste reduction crit- and collaboration, via e.g. representation on interna- ically seek media attention to raise awareness of tional websites and participation in annual interna- their cause. The mainstream print and electronic tional gatherings or conferences. media, including social media and movies, play a role in publicizing the activities of grassroots initiatives 3.9. Measurement of outcome and impact of the against food waste (Edwards and Mercer 2007, Barn- grassroots initiatives ard 2011). Mobilization and awareness-raising is also In this section, we address our second research object- done online. Barnard (2011) examines how freegans ive: to review scholarly evidence of the contribution of practicing dumpster diving in New York City interact grassroots initiatives to reduce food waste and GHG with the media to gain public awareness and support. emissions. In our sample, a first strand of studies During trash tours in New York City, they hold pub- aims to quantify the food rescued and redistributed by lic presentations called ‘Waving the Banana speeches’, grassroots initiatives and/or measures the GHG emis- a critical performance meant not only to catch the sions avoided by saving food from going to waste. A passers-by’s attention but also that of the mass media second strand of studies describes the effects of grass- (Edwards and Mercer 2007). However, this media roots initiatives in a qualitative manner. exposure also poses a threat, as it directs the attention of retailers to the activity and leads them to constrain 3.9.1. Quantified impacts dumpster diving by locking dumpsters or donating Nine studies (n = 9) report the amount of food res- ‘waste food’ to central collection agencies (Barnard cued and redistributed through the studied grassroots 2011). initiatives, mostly in kilograms or tonnes of food, or in the number of equivalent meals which were served 3.8. Networks and collaboration with the rescued food (table 4). Grassroots initiatives rely on networks and collab- The reported amounts of food waste recovered orations to share their cause and gain support. The in tonnes/per year vary widely, from 0.6 tonnes in opportunity for private wholesalers, retailers or farm- the case of the Transition Caf´e Bro Gwaun (Caplan ers to partner up with a grassroots initiative is dis- 2017) to 22 680 tonnes for the City Harvest food cussed in several studies (Barnard 2011, Schneider rescue organization (Walia and Sanders 2017). Evid- 2013, Reynolds et al 2015, Warshawsky 2015, Mirosa ently, the amount of food rescued depends on the et al 2016, Caplan 2017, Lee et al 2017). Lee et al size of the initiative, in particular the number of (2017) point to the increase of total gleaned volume members or volunteers (e.g. 25 000 voluntary food by 50% only by expanding the pool of partner farms savers for Foodsharing vs. 20 volunteers at the Trans- by 24%. Mirosa et al (2016) note that collaborating ition Caf´e Bro Gwaun). Smaller grassroots initiatives

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Table 4. Recovered or prevented food waste reported in sampled studies. Amount of food recovered Tonnes/per year Meals Year Study5

FoodShare N/A 30 000 meals 2015 Mirosa et al (2016) per month Four main Australian food 18 065 12 million meals rescues per day OzHarvest 289 N/A Foodbank 17 573 N/A 2008 Reynolds et al (2015) FareShare 3 N/A 240 N/A SecondBite 3900a 8 million meals 2013 Lindberg et al (2014) Foodsharing platform 1600b N/A 2017 Sarti et al (2017) Olio app N/A 77 288 meals Unknown Team Österreich Tafel 110 N/A 2010 Schneider (2013) Food Forward 150– N/A 2014 Warshawsky (2015) 200 Transition Caf´e Bro Gwaun 0.6 N/A 2015 Caplan (2017) Food Bank of the Southern 4400c N/A 2013 Lee et al (2017), Sönmez Tier et al (2016) City Harvest 22 680 N/A 2015 Walia and Sanders (2017) Inter-Faith Food Shuttle 3175d N/A 2015 a Fresh fruits and vegetables. b Computed based on the overall sum of 8000 tonnes saved since the foundation of the platform until February 2017. c Computed from the output rate (pounds per season) of apple, cabbage, onion, sweet corn and potato. d Computed based on 18 tonnes of food cooked per week. 5 The authors presented are those whose study was included in the sample. Yet, the authors did not necessarily produce the present outcomes but instead derived them from secondary sources, such as grey literature generated by the grassroots initiatives themselves. For clarity, we only refer to the authors of the studies included in our sample. have limited capacity to handle more than a certain and nitrous oxide. Schneider (2013) estimates the amount of food (Caplan 2017, Lee et al 2017), espe- GHG emissions avoided between March 2010 and cially when they want to focus on the local com- March 2011 because of food surplus donation and munity level. Reynolds et al (2015) conclude that redistribution through Team Österreich Tafel at 122 food rescue is a less attractive waste disposal option tonnes CO2-eq. In Lindberg et al (2014), 1000 tonnes compared to landfill or composting, due to higher of rescued food equates to 74 million litres of water economic costs and a higher waste generation rate, and 6000 tonnes CO2-eq of GHG saved (Lindberg although the additional waste generated by food res- et al 2014).4 Based on this, we find GHG emissions cue would still be a very small part of the total saved by SecondBite to amount to 23 400 tonnes CO2- Australian footprint. Similarly, Warshawsky (2015) eq in 2013. Reynolds et al (2015) calculate the embod- suggests that food rescue has a minimal effect on ied CO2-eq of the four Australian main food rescues reducing food waste. A major obstacle to assessing amounting to 148 000 tonnes CO2-eq in 2008. They and comparing the impacts of grassroots initiatives is base their calculation of the CO2 impact on an exten- that data is mostly estimated by donors or reported ded Input-Output Analysis (Reynolds et al 2015). from study participants, and measurement method- This does not include the resources used or GHG ologies varied widely. Moreover, while studies report emissions generated as part of the food rescue oper- the amount of food recovered by the grassroots ini- ations. We estimated the potential GHG savings in tiatives, only one study (Schneider 2013) compares tonnes CO2-eq per year per participant of the grass- the quantities of the redistributed food to the amount roots initiative. This amounts to potential annual sav- of rescued food thrown away, and reports that the ings of 0.25 tonnes CO2-eq per capita for the Team quantity distributed was 92% of the mass of the res- Österreich Tafel (Schneider 2013). However, based on cued food (517 tonnes). However, no study investig- data provided by Reynolds et al (2015), we calculated ates whether the food saved was then actually con- a higher GHG saving potential of 4.43 tonnes CO2-eq sumed by the recipients. per person who could be fed daily from one of the four The ecological effects of food donations in terms main Australian food rescues (Reynolds et al 2015). of GHG emissions is discussed only in three (n = 3) To estimate the amount of GHG emissions con- studies (table 5). The GHG emissions saved from nected to food waste prevention and reduction, food waste prevention are calculated in tonnes CO2 equivalents per year; we assume they include major GHG gases such as carbon dioxide, methane 4 Niklaus et al (2012) cited in Lindberg et al (2014) p 1486.

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Table 5. Ecological impact in terms of prevented GHG emissions (CO2-eq tonnes) measured in sampled studies. Ecological impact of food recovered in GHG

tonnes CO2-eq/year/tonne tonnes CO2- tonnes CO2-eq/year of food recovered eq/year/capita Study

Four main Australian 148 000 8.17 4.43a Reynolds et al food rescues (2015) SecondBite 23 400 6 3.20b Lindberg et al (2014) Team Österreich Tafel 122 1.1 0.25c Schneider (2013) a Computed based on the estimates in Reynolds et al (2015) of the total number who could be fed in one single day from the yearly food rescued. b Computed based on the number of meals saved in 1 year in Lindberg et al (2014) and the assumption of a 3-daily-meal diet. c Computed based on the number of recipients of the initiative reported in Schneider (2013). reliable data on the type and amount of food waste 3.10. Success factors avoided is needed. Thus, unspecific food waste data Despite the lack of numeric data on GHG emissions as provided by Barnard (2011), Warshawsky (2015), saved through food waste prevention and reduction Mirosa et al (2016), Campos and Zapata (2017), Sarti activities by grassroots initiatives, the potentials these et al (2017), Lee et al (2017) or Walia and Sanders initiatives hold for climate change mitigation are still (2017) is not sufficient to assess the potential of relevant to discuss further. In this section we dis- grassroots initiatives to reduce GHG emissions via til the key success factors of grassroots initiatives food waste reduction. to address food waste reduction. We employ the analytical framework from Grabs et al (2016) who 3.9.2. Qualitative impacts define success factors at three inter-connected levels Beyond the nutritional and environmental value on which grassroots initiatives can initiate and drive within the local community, several studies exam- change: the individual, the group, and the soci- ine other impacts of grassroots initiatives. Mirosa etal level. To contextualize and discuss further the et al (2016) analyse the social value created by the success factors of the reviewed grassroots initiatives food rescue social enterprise for its stakeholders and in relation to theory, we use and cite additional liter- volunteers (such as meeting new people; sense of ature on grassroots movements.6 accomplishment in helping others; learning new skills; being involved in the community; improved 3.10.1. Individual-level success factors consumer perceptions of the corporate’s social 3.10.1.1. Fostering the involvement of volunteers and responsibility). users Two studies (n = 2) capture the potential of Volunteer engagement, both in terms of numbers and community gardening to change attitudes and beha- their motivation to participate in a food waste pre- viour towards sustainable food consumptions pat- vention operation (Lee et al 2017), is a cornerstone of terns including food waste reduction (Kim 2017, grassroots initiatives. Moreover, the importance of a Rut and Davies 2018) which can potentially lead to vivid community to ensure the success and sustainab- a footprint reduction. In Kim (2017), the longer a ility of the initiatives should be stressed. We identified gardener engages in the community garden, the more several drivers for fostering the involvement of a com- likely she/he is to report food waste reduction beha- munity of users and volunteers. viours. However, the findings do not address the dir- First, the capacity of grassroots initiatives to con- ectionality of the correlation as people might engage vey their message in a convincing manner to raise in grassroots initiatives against food waste because awareness of social or environmental problems is a they already have a positive attitude and behaviour precondition to spurring action (Bamberg and Möser towards food waste reduction. The potential of grass- 2007). Awareness-raising actions through public rela- roots initiatives to change attitudes and practices tions, media, talks, events, or apps (Edwards and Mer- among food donors towards more environment- cer 2007, Barnard 2011, Campos and Zapata 2017) friendly food waste management is discussed in two provide keys to the question of ‘Why is change neces- studies (n = 2). Mirosa et al (2016) and Barnard sary?’ (Grabs et al 2016). Similarly, the analysis by (2011) respectively report a better dealing with super- Grabs et al (2016) traces the success of the Foodshar- market overstocks and a greater awareness of donors ing movement back to the simultaneous employment as an outcome of the broadcasting of Freegan.info and the actions of FoodShare. These reported changes are traced back to the stakeholders’ new subjective beliefs 6 that changing food waste management brings positive These additional studies are not part of the sampling process. The sample of studies resulting from the systematic review process is outcomes for the council and greater community and given in table 3. For easy reading we do not highlight the paragraphs therefore attracts rewards. particularly. 13 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al of a functional and interactive website as well as large- 2016). However, limited and inconsistent resource scale outreach and awareness-raising efforts. Digital flows often force grassroots initiatives to choose social networks and sharing platforms as described in between the maintenance of operations and expan- Sarti et al (2017) allow people to connect online and sion into new communities (Warshawsky 2015). This negotiate ways to engage in collective action offline is especially problematic when it comes to hand- (Ganglbauer et al 2014). ling perishable food. Yet, we consider Mihaylov Second, grassroots initiatives provide alternative and Perkins’s (2015) argument about environmental value systems and worldviews which respond to the activism’s spread from local to global: transcending question, ‘Why should I get engaged?’ (Grabs et al the local is necessary because the global issue of food 2016). Nonetheless, in the context of food waste waste needs to be put on the national and global polit- reduction, success is reflected rather in attracting a ical agenda. Moreover, as Warshawsky (2015) notes, diverse audience both within media and the general reinforcing the local trap as well as sidestepping the public rather than in other groups with similar structural reasons for food insecurity and food waste alternative ideologies. This supports the urge to frame should be avoided. Grassroots expansion, i.e. the the message in terms of respecting people’s abilities capacity to reach out and [internationally] mobilize to come to their own conclusions and/or avoiding networks may be one way to achieve this (Mihaylov depicting a purely ideological freegan identity (Barn- and Perkins 2015, Grabs et al 2016, Rut and Dav- ard 2011). ies 2018). Networks for broader collaboration via Third, it is essential to make the participation exchange of knowledge, resources and good practices in the initiative easy, and to provide answers to the can expand horizontally, with informal groups, and question, ‘How can I make change happen?’ (Grabs vertically, with organizations, private companies and et al 2016). Our systematic review provides illustra- stakeholders (Rut and Davies 2018). The informal tions from the freegan and Foodsharing movements group provides a relatively intimate, supportive social which managed to attract attention and facilitate food environment in which participants gain the oppor- waste reduction. Yet, the role of households and com- tunity to question and discuss sustainable food beha- munities in driving social change and limiting food viours (Barnard 2011, Kim 2017). The relatively pro- waste might be overestimated (Warshawsky 2015). tected environment of the small group advances social Moreover, the fragmentation of users in sharing eco- learning (Grabs et al 2016, Kim 2017), which includes nomy sectors and the lack of a critical mass can be the sharing of experience and pro-environmental life- barriers to tackling food waste (Sarti et al 2017). Com- styles (Kim 2017) as well as social experimentation munity engagement might be achieved not only in (Kim 2017, Rut and Davies 2018). The larger network a bottom-up manner, but also through agents who in which they are embedded can act as a platform for administrate the initiatives and appeal to the local disseminating and replicating the shared knowledge community for engagement in a top-down manner and experiences in other contexts (Mihaylov and Per- via information sharing (Ganglbauer et al 2014). kins 2015, Kim 2017).

3.10.1.2. Fostering the engagement of recipients 3.10.3. Societal-level success factors Despite the strong links between food waste and food 3.10.3.1. Food regulation, infrastructure, and ethics insecurity, the sampled studies rarely discuss the per- Stringent food safety laws and the lack of common spectives of the recipients of recovered food. Import- regulations for food donation are a major challenge ant social aspects yet neglected include how recovered for grassroots initiatives engaged in the recovering, food can affect people’s dignity (Lindberg et al 2014) sharing and redistributing of food. Where food dona- or lead to stigmatization of the poor (Schneider 2013, tion regulations exist, as in the EU, these appeared to Caplan 2017). As Caplan (2017) shows in the case of add costs to participating member states and make the Transition Caf´e Bro Gwaun, grassroots initiatives food donation less attractive (Schneider 2013). In the might experience local opposition due to conceptions case of food sharing, there is a denial of responsib- of rescued food as dubious since given away by food ility for any food-related products shared by users outlets, and as intended for poorer people only. This (Sarti et al 2017). Food safety concerns are also often tension reveals the need for strong involvement and used as an excuse by potential donors for not donat- communication in recipient communities to under- ing food (Schneider 2013). Thus, what is needed are line the adequacy of recovered food for consumption. clear guidelines for onsite food donation manage- In Walia and Sanders (2017), a culinary job-training ment (i.e. which products are suitable for donation, program for unemployed adults uses rescued food, how to handle specific goods, agreement templates) empowering the participants as agents in food waste (Schneider 2013). Furthermore, there is a need for reduction efforts. an improved infrastructural framework for separated food waste disposal. Waliaand Sanders (2017) sugges- 3.10.2. Group-level success factors ted an identifiable food waste bin; the end-use destin- The organizational structure and size of grassroots ation for food waste and an automated sorting mech- initiatives can be relevant success factors (Grabs et al anism to account for the disposal of non-food waste

14 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al in the food waste bin. Lastly, a broader discussion high social and economic costs, grassroots initiat- should be held at society level about the ethics of ives could redirect their collaboration towards the selling goods whose best-before date has passed. The supply chain to mitigate the occurrence of surplus confusion between the meaning of best-before and food (Lindberg et al 2014, Warshawsky 2015). This use-by dates should be overcome by increasing public would help to address the first sub-priority in the awareness and informing (Schneider 2013). Food Waste Hierarchy: avoiding surplus food generation through food production and consumption 4. Discussion (Papargyropoulou et al 2014). Besides, the potential of grassroots initiatives for food waste reduction to 4.1. Food insecurity vs. climate change? limit GHG emissions could be strengthened through The systematic review revealed a somewhat surprising a more holistic approach. This could address not lack of connection between food insecurity (social only the symptom of food waste, but also link it to priority) and climate change mitigation (environ- the promotion of sustainable dietary choices, food mental priority) (table 3). This appears notably in the shopping habits, food waste management (Barnard narratives of grassroots initiatives emphasizing food 2011, Kim 2017), or social integration through return redistribution, which elude climate change mitiga- to work training (Caplan 2017, Walia and Sanders tion as a major goal. Mirosa et al (2016) shows the 2017). failure of stakeholders to identify the environmental outcomes associated with their work with FoodShare. 4.2. Limitations of the review This is due to FoodShare’s focus on nutrition and In spite of searching for studies in three languages combatting food insecurity, which compel narrat- and with no geographical restriction, the final sample ives of human hardship rather than climate change comprises studies conducted exclusively in urban mitigation. areas of high-income, mostly Anglo-Saxon countries, Additionally, there is a scholarly debate on published in English. This makes a generalization whether the food charity sector and to an extent the of the findings to other contexts difficult. Given the food waste and surplus recovery sector are unsus- small sample size, it is only partly possible to com- tainable with respect to the health dimension of pile and analyse quantitative impacts in terms of sustainability when the food rescued is nutrition- GHG emissions. Instead, we provide a narrative ana- ally inadequate. This in turn leads to many of those lysis while also extracting and compiling any out- getting the food to remain food insecure (Poppen- come measures when available. The focus on peer- dieck 1999, Warshawsky 2015) or feeling ashamed reviewed work entails a trade-off with exhaustiveness; and humiliated (van der Horst et al 2014). While food the grey literature would have narrowed the know- rescue serves an urgent, short-term moral imperative ledge gap left by the academic literature (Adams et al to feed hungry people, the activity can undermine 2017). Within the sample, the variety of analytical social justice and long-term access to adequate food breadth and study designs hampered their compar- and nutrition. This poses the question of whether ability. Nonetheless and paradoxically, this variety cherry-picking food which is more ‘worthy’ of being offered a way to triangulate the findings of the studies saved is ethically and environmentally justifiable. and develop a more comprehensive understanding of Lindberg et al (2014) argued for rescuing ‘valuable’ grassroots level food waste reduction. and ‘most nutritious’ food to lower the risk of diet- related disease, setting food waste reduction and 5. Conclusion food insecurity reduction as both complementary and competing missions. Furthermore, this raises This systematic review examined the peer-reviewed the question as to the criteria by which this priority- evidence on grassroots initiatives’ potential to limit setting should take place. One could argue differ- food waste and GHG emissions. We found 15 relevant ently, in favour of privileging the rescue of the most studies which represent a small but recent and grow- culturally and socially adapted food or rather fol- ing interest in the topic. The findings of the studies lowing environmental criteria and privileging the are mostly of a qualitative nature, exploring the ini- most environment-friendly food, or on the contrary tiatives’ organizational structure, goals and available the food which required the most resources to be resources. All grassroots initiatives studied embrace produced. the goal of avoiding food going to landfill and con- Finally, the reviewed studies cannot show effi- sidering human consumption as a priority. Each ini- ciencies of food waste prevention grassroots initiat- tiative’s focus is on one of two specific priorities: (1) ives. While the prevention and recovery of food is preventing avoidable food waste or (2) promoting the more desirable than its wastage, both morally, eth- redistribution of food surplus to people living in food ically and environmentally speaking, the grassroots poverty. work needs to be scaled up along the entire sup- The organizational structures of the grassroots ply chain, rather than solely focusing on the con- initiatives take a variety of forms. These range from sumer. Instead of only handling food surplus at low-profile, informal but highly connected social

15 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al endeavours, such as global food movements, or more and ultimately eaten food are missing. Compared to localized citizen-led initiatives including online social the mean per capita GHG saving potential of redu- platforms, to high-profile, professionalized CSOs or cing avoidable food waste in households compiled social enterprises. All reviewed initiatives rely highly in Ivanova et al (2020), the computed GHG saving on an important pool of volunteers that compensate potential of food waste prevention and reduction for their low budgets. achieved through grassroots initiatives seems high but Few studies provide information on the compos- would need to be further investigated. ition of the rescued food, mostly referring to any type The systematic review raises these main directions of non-spoiled edibles. Some nonetheless discuss the for future research. Notably, there is a knowledge gap decision to privilege the rescue of healthy food, evok- to be filled: to date, tangible estimates of the extent to ing the complexity of combining the ethical and social which rescuing and redistributing food reduces food requirements of initiatives that prevent food waste by waste and GHG emissions are missing. The genera- saving and redistributing it. Initiatives secure collab- tion of data quantifying the food rescued and sub- oration across public and private sectors as a crucial sequently eaten by humans is needed. This suggests way to share their cause and gain support as well as a more academic knowledge in the black box between supply of food to save from the bin. The food ‘waste’ the group level and the individual level, i.e. the recip- supply mostly emanates from the tertiary and second- ients and users of food saved. At the same time, there ary sectors, which are also being increasingly called is a need for studies to show how other community- upon to provide financial and material support. The based efforts to promote alternative ways of produ- public sector is mobilized to rescue food to a limited cing and eating food, such as those promoting diet extent. It appears as a stakeholder to mobilize and shifts, overlap with efforts fighting food waste. secure funds as well as for the (tacit) authorization to collect food about to be wasted and to redistribute it. Some developments in legal and regulatory frame- Acknowledgments works have eased food prevention activities of grassroots initiatives but hurdles in food safety regulations We wish to thank the editors and guest editors Pro- and local food management systems still hamper the fessor Dr Jan Minx and Professor Dr Felix Creutzig for work of grassroots initiatives. Their success in food their trust and invitation to contribute to the Envir- waste reduction also relies greatly on their capacity to onmental Research Letters focus Issue on Demand- capture media attention. This allows them to increase side Solutions. We are thankful to the three anonym- awareness among the general public as well as retail- ous reviewers for their valuable comments which ers on the issue of food waste and to show the ease of helped improve the manuscript. No financial support addressing the problem. was received to carry out this work. Predictably, few studies attempt to identify quan- The authors acknowledge support by the German tifiable outcomes of the grassroots initiatives, either in Research Foundation and the Open Access Public- terms of amounts of food rescued or redistributed or ation Fund of TU Berlin. In addition, the authors in GHG emissions avoided by saving food from going acknowledge partial funding of the Austrian Science to waste. The few studies which include an ecological Fund (FWF) for the project ”High-dimensional stat- assessment of the GHG emissions avoided focus on istical learning: New methods to advance economic food recovery via bigger long-established food sur- and sustainability policies” (ZK 35), jointly carried plus rescues. The amounts of food saved are highly out by WU Vienna University of Economics and Busi- dependent on the sizes of the initiatives, in particu- ness, Paris Lodron University Salzburg, TUWien, and lar the volume of users or participants. The organiza- the Austrian Institute of Economic Research (WIFO). tional structure is another factor which can constrain the volume of food grassroots initiatives handle and Author contributions save. The food waste and ecological outcomes presen- MN conceived and coordinated the review, conducted in the studies lack comparability and external ted the initial search strategy, supervised the reference validity due to the diversity of methodologies used management, screened on title and abstract followed and because they are compiled from secondary by full text, conceived the coding system, drafted the sources, mostly originating from the grassroots ini- initial manuscript and implemented revision of the tiatives themselves. Only four studies (n = 4) dis- draft. KD assisted with the initial search strategy, cussed the potential of grassroots initiatives to reduce adjusted conflicts between screeners at abstract and food waste and GHG emissions and conclude that title screening level, provided critical inputs on the although it is preferable to landfilling or compost- coding system, read full texts, provided critical inputs ing, the effect of food rescue by the investigated grass- with the revised manuscript draft. AW screened on roots initiatives is minimal. Moreover, apart from title and abstract, adjusted conflicts between screen- one study which compiled how much of the food ers at full text reading level, provided critical inputs saved was actually distributed, estimates of the saved on the coding system, read full texts, and provided

16 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al critical input on the initial manuscript draft. VK Conflicts of interest screened on title and abstract, completed data extrac- tion, assisted in the reference management (sourcing The authors have no conflicts of interest to disclose. full text articles), screened on title and abstract followed by full texts, and assisted with the initial and revised manuscript draft. NL had the research idea, composed the team, provided critical input to the Data availability methods and overall guidance through the review and provided critical inputs on the manuscript draft. All Data sharing is not applicable to this article as no new authors provided input on drafts. data were created or analysed in this study.

17 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ’ ∗ ‘ ‘ ∗ ∗ ∗ ∗ ∗ ∗ Term 3 GHG „carbon dioxide‘ CO2 Methane ‘greenhouse gas CH4 ‘nitrous oxide‘ ‘nitrus oxide‘ N2O Hydrofluorcarbon$ HFC F-gas ‘fluorinated gas emission ‘carbon footprint’ Footprint ‘climate change’ ‘climate impact’ ‘environmental impact ‘Global warming’ Foodprint AND OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR ’ ∗ ∗ ∗ ∗ ∗ ∗ up ‘ ∗ ∗ scale‘ ∗ ∗ ∗ ∗ ∗ ∗ ∗ grassroots Term 2 ‘collective action‘ grass-root initiative movement communit citizen ‘bottom ‘circular economy‘ household ‘small project NGO ’civil society‘ food$sharing responsible ethic sustainabl engage ‘food bank microbial consumer CSO Search strategy (Web of Science, English language). Table A1. OR AND OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR OR NOT OR OR ‘ ∗ ∗ food‘ ∗ ‘food spoilage‘ Term 1 ‘food wast ‘wast ‘edible food‘ ‘plate waste‘ ‘beverage waste‘ leftover ‘Food surplus” ‘Surplus food ‘ ‘Food loss‘ Appendix OR OR OR OR OR OR OR OR OR OR OR

18 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ’ ∗ OR ∗ ∗ ) ∗ OR ∗ OR ∗ OR ∗ OR CO2 OR ∗ ∗ ∗ OR Klimawandel OR OR Lebensmit- ∗ ∗ mikrobiell OR Lebensmit- ’ OR ‘überschüssige OR Bürger OR nachhalitg ∗ ∗ = OR Distickstoffmonoxid OR Essenreste ∗ ∗ OR Projekt OR Tafel) OR Zivilgesellschaft OR Küchenabfälle ∗ OR Getränkeabfälle ∗ ∗ ∗ ∗ root$ OR ‘Lebensmittel rett ∗ ∗ OR Kohlendioxid ∗ OR haushalt OR Verbraucher Fußabdruck ∗ ∗ ) NOT TS ’ OR ‘Wegwerfen von Lebensmitteln’ ∗ OR NGO OR NPO OR NRO OR OR ethisch ∗ Lebensmittel ∗ ∗ ∗ OR Speisereste OR Bewegung ∗ ∗ (Emission (Gemeinschaft OR Treibhausgas = = ∗ (Lebensmittelabfälle = OR verantwort Engagement OR engagier AND TS AND LANGUAGE: (German) AND DOCUMENT TYPES: (Article) AND TS OR Initiativ Kreislaufwirtschaft OR Konsument food$sharing OR Grass Methan OR Lachgas OR Fluorkohlenwasserstoffe OR F$KW OR HFC-Gase OR Footprint OR Foodprint OR Umweltauswirkung Umweltbelastung TS OR Nahrungsmittelabfälle OR Lebensmittelverluste Essenabfälle telsverschwendung OR ‘Verschwendung von Lebensmittel’ OR Speiseabfälle telüberschüss OR Nahrungsmittelüberschüss OR ‘überschüssige Nahrungssmittel German ∗ ∗ ∗ ∗ ∗ ees OR ´ ethique enage$ ´ ´ ’ OR ∗ ene ’ OR ‘perte ` OR ∗ ’ OR denr ∗ ∗ frigorig ∗ ero$gaspi ´ alimentaire ethane OR CH4 OR ‘pro- ´ ∗ ) ∗ OR z et$ alimentaire ˆ ∗ ) economie circulaire’ OR m ∗ ´ ech ´ OR ONG$ OR association$ OR echauffement climatique’ OR ‘impact ´ ach ˆ ’) a effet de serre’ OR ‘GES’ OR ‘dioxyde ∗ ` ∗ AND LANGUAGE: (French) AND DOC- OR initiative$ OR populaire$ OR citoyen Search strings. ∗ ’ OR ‘invendu ’ OR ‘d OR ‘gaspillage alimentaire’ OR ‘reste ∗ ∗ ∗ ∗ (‘gaz (anti$gaspi = = e civile’ OR OSC$ OR ‘consommation collab- ´ et (gaspi ´ Table A2. = ‘empreinte carbone’ OR ‘empreinte’ OR ‘changement climatique’ OR ‘r environnement NOT microb UMENT TYPES: (Article) AND TS de carbone’ OR CO2 OR m toxyde d’azote’ OR N2O OR hydrofluorocarbures OR HFC$ OR emission$ OR ‘fluide orative’ OR food$sharing OR responsable$ OR AND TS communaut OR bottom$up OR ‘ OR consommat ‘Soci OR durable$ OR engage alimentaire OR g alimentaire alimentaire French TS ∗ ∗ OR ∗ OR ∗ OR ‘flu- ∗ OR engage up OR ‘cir- OR movement ∗ ∗ ∗ OR ‘environmental OR ‘food sharing’ OR F-gas ∗ ∗ OR ‘small-scale’ OR ∗ ∗ OR bottom ∗ OR sustainab OR ‘collective action’ OR ∗ ∗ OR ethic ∗ OR ‘Food bank’ OR ‘Food banks’) OR consumer OR ‘carbon dioxide’ OR CO2 OR methane (‘greenhouse gas’ OR ‘greenhouse gases’ (communit (microbial) AND LANGUAGE: (English) ∗ OR grass-root OR initiative ∗ ∗ ∗ = = = OR ‘civil society’ OR CSO ∗ (‘food waste’ OR ‘food wastage’ OR ‘wasting food’ = AND TS OR GHG OR CH4 OR ‘nitrous oxide’ OROR ‘nitrus hydrofluorcarbons oxide’ OR OR HFC N2O NOT TS AND DOCUMENT TYPES: (Article) orinated gas’ OR ‘fluorinated gases’ OR emission ‘carbon footprint’ OR footprint OR ‘climate‘climate change’ impact’ OR OR environment impact’ OR ‘global warming’ or ‘foodprint’) OR project cular economy’ OR household NGO OR responsib OR citizen grassroot AND TS English TS OR ‘food spoilage’ OR ‘edible food’‘plate OR wastage’ ‘plate OR waste’ ‘beverage OR waste’ OR‘wasted leftover food’ OR ‘organic waste’ OR‘food ‘wasted surplus’ food’ OR OR ‘surplus food’ OR ‘food loss’) Web of Science Using Social Sciences Cita- tion Index (SSCI)— 1956–present 2000– 2018

19 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ’ ∗ ∗ ) ∗ OR ∗ OR ∗ OR ∗ ∗ OR Lebensmit- ∗ OR Lebensmit- ’ OR ‘überschüssige OR Bürger OR nachhalitg ∗ ∗ OR Essenreste ∗ ∗ OR Projekt OR Tafel) OR Zivilgesellschaft OR Küchenabfälle OR Getränkeabfälle ∗ ∗ ∗ ∗ root$ OR ‘Lebensmittel rett ∗ ∗ ∗ OR haushalt OR Verbraucher ∗ ’ OR ‘Wegwerfen von Lebensmitteln’ OR NGO OR NPO OR NRO OR OR ethisch ∗ Lebensmittel ∗ ∗ ∗ OR Speisereste OR Bewegung ∗ ∗ (Gemeinschaft mikrobiell = = (Lebensmittelabfälle = (Lebensmittel OR Verschwendung OR Essenabfälle OR Lebensmittelsverschwendung) AND (Gemeinschaft OR Zivilgesellschaft OR Initiativ) n/a OR verantwort Engagement OR engagier (Lebensmittel OR Verschwendung OR Essenabfälle OR Lebensmittelsverschwendung) AND (Gemeinschaft OR Zivilgesellschaft OR Initiativ) AND (EmissionFußabdruck OR OR Klimawandel) TS OR Nahrungsmittelabfälle OR Lebensmittelverluste AND TS OR Initiativ Kreislaufwirtschaft OR Konsument food$sharing OR Grass NOT TS AND LANGUAGE: (German) AND DOCUMENT TYPES: (Article) Essenabfälle telsverschwendung OR ‘Verschwendung von Lebensmittel’ OR Speiseabfälle telüberschüss OR Nahrungsmittelüberschüss OR ‘überschüssige Nahrungssmittel German ∗ ∗ ∗ ∗ ees OR ´ ethique enage$ ´ ´ ’ OR ‘perte OR ∗ ’ OR denr ∗ ∗ OR ‘restes alimentaires’ OR ‘restes alimentaires’ ∗ ∗ ero$gaspi ´ alimentaire ∗ ∗ ∗ ) e civile’ OR ‘initiative’ OR e civile’ OR ‘initiative’ OR ´ ´ ∗ OR z et et ´ ´ et$ alimentaire ˆ ∗ ) economie circulaire’ OR m ∗ ´ ech ´ OR ONG$ OR association$ OR ach ˆ ∗ OR initiative$ OR populaire$ OR citoyen ∗ ’ OR ‘invendu ’ OR ‘d OR ‘gaspillage alimentaire’ OR ‘reste ∗ ∗ ∗ ∗ (anti$gaspi Search strings. = e civile’ OR OSC$ OR ‘consommation collab- ´ acher) AND (‘soci acher) AND (‘soci ˆ ˆ et (gaspi ´ = Table A2. ‘gaspillage alimentaire’—‘microb’ bottom-up) NOT microb (‘gaspillage alimentaire’ OR ‘invendus alimentaires’ OR ‘pertes alimentaires’ OR gaspil OR g communaut bottom-up) NOT microb AND TS OR bottom$up OR ‘ OR consommat ‘Soci orative’ OR food$sharing OR responsable$ OR NOT microb AND LANGUAGE: (French) AND DOCUMENT TYPES: (Article) (‘gaspillage alimentaire’ OR ‘invendus alimentaires’ OR ‘pertes alimentaires’ OR gaspil OR g alimentaire alimentaire alimentaire OR g OR durable$ OR engage French TS ∗ ∗ OR ∗ OR engage up OR ‘cir- ‘civil society’ OR movement ∗ ∗ ∗ + OR ‘food sharing’ ∗ OR ‘small-scale’ OR ∗ OR bottom ∗ OR sustainab OR ‘collective action’ OR ∗ ∗ OR ethic ∗ ‘greenhouse’ (optional) -’microbial’: 4 hits, OR ‘Food bank’ OR ‘Food banks’) OR consumer (communit (microbial) ∗ OR grass-root OR initiative + ∗ ∗ = = OR ‘civil society’ OR CSO ∗ (‘food waste’ OR ‘food wastage’ OR ‘wasting food’ = including 3 duplicates) (optional) (‘Food waste’ OR ‘food surplus’ OR(‘civil ‘food society’ loss’) OR AND grassroots) NOT microbial NGO OR project cular economy’ OR household OR responsib NOT TS AND LANGUAGE: (English) AND DOCUMENT TYPES: (Article) (‘Food waste’ OR ‘food surplus’ OR(‘civil ‘food society’ loss’) OR AND grassroots) AND (‘greenhouseOR gases’ footprint OR ‘climate change’) NOT microbial grassroot OR citizen AND TS English TS OR ‘food spoilage’ OR ‘edible food’‘plate OR wastage’ ‘plate OR waste’ ‘beverage OR waste’ OR‘wasted leftover food’ OR ‘organic waste’ OR‘food ‘wasted surplus’ food’ OR OR ‘surplus food’ OR ‘food loss’) AGRIS Journal articles Books ‘food waste’ -’microbial’ (‘food waste’ Science Direct

20 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al German n/a n/a ∗ ∗ ∗ OR ’ OR ∗ ∗ ∗ ethique ´ OR bot- enage OU ´ ∗ ero$gaspi ´ emission OU ´ OR z ∗ e civile’ OU OSC ´ et ´ et$ alimentaire ˆ echets alimentaires’ OU ´ ’ OR ‘invendu a effet de serre’ OU ` ethane OU ‘protoxyde ´ ∗ ech ´ sharing OU responsable ∗ enage$ OR consommat ´ OU initiative OU populaire OU a effet de serre’ OR ‘GES’ OR ` ’ OR ‘d ) ET (‘gaz ∗ ∗ ∗ e civile’ OR ‘OSC$’ OR ‘consom- ´ ethane OR ch4 OR ‘protoxyde alimentaire ´ et ´ ) AND (anti$gaspi ∗ ∗ economie circulaire’ OU m ´ echauffement climatique’ OR ‘impact ´ ach ˆ ) AND (‘gaz alimentaire ∗ ∗ ’ OR ‘empreinte carbone’ OR ‘empreinte’ OR ∗ ) ET (communaut OR initiative$ OR populaire$ OR citoyen ’) AND NOT TITLE-ABS-KEY (microbial) AND ∗ ∗ ∗ ene ` enes’ OU ‘empreinte’ OU ‘changement climatique’ OU ` ach ˆ OU ONG OU Association OU ‘soci economie circulaire’ OR m ´ ’ OR ‘perte OU durable OU engage ∗ ∗ ∗ OU g frigorig OU ‘gaspillage alimentaire’ OU ‘restes alimentaires’ OU ‘inven- ∗ ∗ ∗ ee ees OR alimentaire OR g ´ ´ ethiqu ´ echauffement climatique’ OU ‘impact’) SAUF(microbien) ´ ‘fluides frigorig ‘r denr OU ‘consommation collaborative’ OU food OU ‘GES’ OU ‘dioxyde de carbone’ OUd’azote’ CO2 OU OU N2O m OU hydrofluorocarbures OU HFC OU (gaspi dus alimentaires’ OU ‘pertes alimentaires’ OU d citoyen OU bottom w/1 up OUconsommat ‘ environnementa DOCTYPE (ar) AND PUBYEAR > 1999LANGUAGE (french) AND PUBYEAR < 2019 AND mation collaborative’ OR food$sharing OR responsable$OR OR durable$ OR engage ‘dioxyde de carbone’ OR co2 ORd’azote’ m OR n2o OR hydrofluorocarbures OR‘fluide hfc$ OR emission$ OR ‘changement climatique’ OR ‘r French (‘gaspillage alimentaire’ OR ‘reste ‘ONG$’ OR association$ OR ‘Soci OR communaut alimentaire denr tom$up OR ‘ Search strings. ∗ ∗ Table A2. up OR ‘circular economy’ ∗ OR grass-root OR initiative ∗ OR ‘Food banks’) AND TITLE-ABS- OR ‘wasted food’ OR ‘organic waste’ ∗ ∗ OR bottom ∗ OR engage ∗ OR consumer OR ethic ∗ ∗ n/a OR ‘food surplus’ OR ‘food loss’)OR AND ‘collective TITLE-ABS-KEY action’ (communit OR grassroot English TITLE-ABS-KEY (‘food waste’ OR ‘food wastage’OR OR ‘food ‘wasting spoilage’ food’ OR ‘edible food’OR OR ‘beverage ‘plate waste’ waste’ OR OR leftover ‘plate wastage’ OR citizen OR ‘small-scale’ OR ‘ngo$’ OR ‘civilresponsib society’ OR ‘food sharing’ OR KEY (‘greenhouse gas’ OR ‘greenhouse gases’methane OR OR ‘carbon ‘nitrous dioxide’ OR oxide’ OR ‘nitrusOR oxide’ ‘fluorinated OR gas’ hydrofluorcarbons OR ‘fluorinated gases’change’ OR OR ‘footprint’ ‘environmental OR impact’ ‘climate OR ‘globalTITLE-ABS-KEY warming’) (microbial) AND AND NOT DOCTYPE (ar) AND1999 PUBYEAR AND > PUBYEAR < 2019 CAIRN Scopus 2000-2018 Journal articles

21 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al ∗ ∗ ) ∗ ∗ | ∗ ) (Emission ) -mikrobiell OR Treibhausgas ∗ ∗ ∗ OR Klimawandel Fußabdruck ∗ ∗ ∗ | Grassroot | Grassroot ∗ ∗ Fußabdruck | ökologische ∗ ∗ ) AND (Emission ) -mikrobiell ∗ ∗ | ‘Wegwerfen von Lebensmitteln’) (Zivil- ∗ OR Verschwendung OR ‘Wegwerfen von | ‘Wegwerfen von Lebensmitteln’) (Zivil- ∗ ∗ ∗ n/a (~Lebensmittelabfälle OR ~Küchenabfälle OR Speisereste Lebensmitteln’) AND (Zivilgesellschaft OR Initiativ OR Bewegung OR ökologische (~Lebensmittelabfälle | ~Lebensmittelverschwendung | Speisereste gesellschaft | Initiativ | Treibhausgas (~Lebensmittelabfälle | ~Lebensmittelverschwendung | Speisereste gesellschaft | Initiativ NOT mikrobiell German Klimawandel e e ´ ´ 10) et et ´ ´ = 9) = 15) acher) (‘soci acher) (‘soci ˆ ˆ = 4) 0) 8) = (n 19) 0) = ∗ = 1) a effet de serre’ | empre- ` = = 16) = 9) 6) = = 0) = = e civile’ (n ´ et ´ 144) = economie circulaire’ (n ´ ethique (n ´ | ‘restes alimentaires’ | g | ‘restes alimentaires’ | g Search strings. ∗ ∗ Table A2. n/a gaspillage alimentaire food sharing (n gaspillage alimentaire responsable (n gaspillage alimentaire gaspillage alimentaire (n gaspillage alimentaire initiative (n gaspillage alimentaire et communaut gaspillage alimentaire populaire (n gaspillage alimentaire ‘soci gaspillage alimentaire bottom-up (n gaspillage alimentaire citoyen (n gaspillage alimentaire association (n gaspillage alimentaire ONG (n gaspillage alimentaire ‘ gaspillage alimentaire ‘consommation collaborative’ (n civile’ |’initiative’ | bottom-up) (‘gas inte | ‘changement climatique’) -microb civile’ |’initiative’ | bottom-up) -microb French (‘gaspillage alimentaire’ | ‘invendus alimentaires’ |mentaires’ ‘pertes |gaspil ali- (‘gaspillage alimentaire’ | ‘invendus alimentaires’ |mentaires’ ‘pertes |gaspil ali- n/a n/a English (‘Food Waste’ | ‘Food surplus’ | ‘Food(‘civil society’ Loss’) | grassroots) (‘greenhouse gases’ | footprint | ‘climate change’)—microbial (‘Food Waste’ | ‘Food surplus’ | ‘Food(‘civil society’ Loss’) | grassroots)—microbial Google Scholars Articles and contribution in books excluding citations. WiSo Articles and eBooks German INRA

22 Environ. Res. Lett. 15 (2020) 123008 N Mariam et al

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