There is an increasing political and scientific consensus about the need to reduce global food waste. In 2015, the United Nations’ Sustainable Development Goal 12.3 set the target of “By 2030, halve per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses” (United Nations 2015). This target stems from a broad understanding of the negative consequences of food losses and waste, including the waste of land, water and energy, while causing unnecessary emissions of greenhouse gases. The Food and Agriculture Organization of the United Nations (FAO) has estimated that food losses and waste account for more than 10% of global energy consumption (FAO 2017). Hence, food waste is a major contributor to climate change. Furthermore, wasting food is a moral concern, since it impacts global food security and increases the gap between affluent and low-income people. Food produced for human consumption is wasted at the same time as a large part of the global population suffers from hunger and malnutrition. From an economic point of view, inefficiencies accrue from food losses and waste for both organisations such as farms, food manufacturers, retailers and restaurants and households.

Food waste can be characterised as a “wicked problem” (Närvänen et al. 2019), which are defined as unstructured, cross-cutting and relentless (Weber and Khademian 2008; see also Rittel and Webber 1973). We elaborate on these characteristics of food waste as a wicked problem in this introduction for the book Food Waste Management: Solving the Wicked Problem.

Firstly, food waste is an unstructured problem, because its precise causes and effects are difficult to identify, and there is no shared problem definition. Even though there is now a growing body of research focussing on food waste quantification and measurement (see, e.g., Parfitt et al. 2010; Thyberg et al. 2015; Xue et al. 2017; see Hartikainen et al., Chapter 16) as well as its key antecedents (see, e.g., Aschemann-Witzel et al. 2015; Porpino et al. 2015; Stancu et al. 2016), there is no unified agreement on the definition of food waste. Some definitions take into account both food loss and waste (Buzby et al. 2014; Gustavsson et al. 2011) throughout the food system, while others highlight dimensions such as edibility versus inedibility or avoidability versus unavoidability (see, e.g., Blichfeldt et al. 2015; Papargyropoulou et al. 2014; Katajajuuri et al. 2014).

In this book, we adopt a broad perspective and consider all types of food surplus, loss and waste within the food system. Even though food waste can be defined in various ways, a solution orientation is essential. One approach for evaluating the different types of solutions is the food waste hierarchy. It refers to the order of preference for action suggested by governmental bodies and political institutions both in the European Union (EU) (ECA 2016; Papargyropoulou et al. 2014) and in the United States (US) (EPA, n.d.). The primary focus should be on actions that prevent food waste from occurring. The second most preferred measures are those that utilise surplus food or potential food waste for feeding people, that is, mainly food donations. If this is not possible, the next level suggests food waste should be used as an animal feed. The bottom levels, or least preferred actions, relate to recycling food waste into compost or converting it into biogas or biodiesel. The least preferred option is the disposal of food waste into landfills or by incineration.

It must, however, be noted that no solution can solve the whole problem (Weber and Khademian 2008), and, hence, each solution also changes how the problem of food waste is perceived. The solutions for tackling the food waste problem—such as reducing it at the source, distributing it to people in need and reusing it to feed animals—may also compete with each other (Mourad 2016). For instance, depending on the solution, food waste can be seen as a problem to be addressed, as food or as a resource for further processing. Furthermore, the boundary between food and waste is often negotiable in everyday life, and, hence, for actors attempting to reduce food waste, the phenomenon is always context-bound and dynamic (Mattila et al. 2018b).

Secondly, food waste is also a cross-cutting problem as it involves many stakeholders in the food system from farm to fork (Parfitt et al. 2010). However, according to statistics, in the developed world, food waste occurs mainly at the end of the food chain: by food distribution and especially households (Bräutigam et al. 2014 ). According to the FAO (Gustavsson et al. 2011), the total estimate of food losses and waste is about one-third of edible food produced, or 1.3 billion tonnes per year. In the developed countries, more than 40% of food waste emerges at the retail and consumption levels. In developing countries, in contrast, most of the food losses and waste occur in the post-harvest and processing stages. Also, food waste-related scientific research has focussed mainly on the developed countries and downstream food waste, especially on the consumer or household level, but also on retailers, hotels and restaurants (see, e.g., Aschemann-Witzel et al. 2015, 2016; Filimonau and Gherbin 2017; Garrone et al. 2014; Graham-Rowe et al. 2014; Papargyropoulou et al. 2016; Parfitt et al. 2010).

Many of the suggested solutions for reducing food waste in the literature have focussed on changing the attitudes and behaviour of individuals (see van Geffen et al., Chapter 2), for example through awareness-raising informational campaigns (for a review, see Aschemann-Witzel et al. 2017; Quested et al. 2013; see Sutinen, Chapter 9). More recently, other types of interventions such as those based on behavioural economics (Wansink 2018; see de Visser-Amundson and Kleijnen, Chapter 3) and design thinking or technological innovations (Hebrok and Boks 2017; see Burke and Napawan, Chapter 7; Lake et al., Chapter 8) have been suggested to complement the informational interventions. Some countries, such as South Korea, have even utilised public policy interventions through regulations that are intended to reduce household food waste and increase its recycling. In South Korea, households are now charged based on the food waste they have produced, and regulations have been recently amended to enable converting the resulting food waste with the help of insects into animal feed (Bagherzadeh et al. 2014; Jackson 2018; see Fowles and Nansen, Chapter 12).

In addition to behaviour change, some existing solutions concern organisations’ strategies, such as linking food waste reduction with corporate social responsibility (CSR) (see Moser, Chapter 4). Many retailers have in recent years started to voluntarily reduce their food waste by, for instance, donating food to charities and food banks, or redirecting their waste to be used for biofuel production. Furthermore , retailers occupy a critical intermediary position (Welch et al. 2018) and thus can impact their own food waste but also that of other actors, such as farmers and consumers (see Gollnhofer and Boller, Chapter 5; Alhonnoro et al., Chapter 6). Some European countries, such as France and Italy, have also set legal obligations for retailers to donate food (Vaqué 2017). Different policy-level solutions regarding retailer food waste have been identified, including awareness campaigns and changing legislation, norms and standards related to labelling, product standards and food donation (Gruber et al. 2016).

However, in developing solutions for food waste reduction, it must be acknowledged that even though food distributors and households may produce the greatest amount of (quantifiable) food waste, they should not be held exclusively responsible for its emergence (Evans 2011). Instead, food waste occurs at the intersection of several influences across the food system. These include the myriad ways in which food is, for instance, produced, transported, processed, packaged and stored on the supermarket shelves and at home. For instance, at the consumer level, many routines and contexts influence the emergence of food waste, not only those directly related to the disposal of food (Evans 2014). Various value trade-offs characterise food waste as a wicked problem—actors must often balance between different societal values (Cappellini 2009; Cappellini and Parsons 2012; Evans 2012a, b; Devin and Richards 2018; Welch et al. 2018). The ethical values and principles connected with food waste that influence actors’ perceptions of the problem have a significant impact on the suggested solutions and how they are mobilised by actors (see Uusitalo and Takala, Chapter 10; Raippalinna, Chapter 11).

Finally, food waste represents a relentless problem, which cannot be solved once and for all (Weber and Khademian 2008). Wicked problems require various actors to be engaged in solving them through different activities and at different le...