The concept of sustainability can therefore be presented as the tensions which occur between population, consumption and technologies which has an environmental impact (Lewis and Maslin 2018; Dobson 2016; Moreno et al 2016; Eggleton 2013). The use of these variables of population, consumption and technologies supports a range of perspectives as regards sustainability which not only include the relationship between these, such as the relationship between growing population and its impact on consumption, but may also undertake a particular area of focus such as the increasing breadth of research regarding the role of science and technology in decreasing social inequalities and increasing environmental resilience (Lewis and Maslin 2018; Braungart and McDonough 2009; Beder 2006). The complexity of the relationships between these variables of population, consumption and technologies relates to the dynamics and interdependencies between these and these may see the concepts of sustainable development and environment being depicted as trade-offs (Lewis and Maslin 2018; Moreno et al 2016; Sachs 2015). However, this inherent difficulty in the approach to sustainability was addressed by the Brundtland Report (1987) which states that sustainability should not be seen as a trade-off between economic and societal development and the environment, but rather as a boundary as to how these issues can be addressed without creating detrimental harm to the earth and thus negatively impacting future generations (Mulvihill and Harris Ali 2017; Crane and Matten 2016; Blowfield and Murray 2014).
The concept of sustainability can therefore be presented as supporting a process of complex problem-solving as regards the current challenges but also encourages and promotes the needs to address multiple stakeholders and their expectations (Feil and Schreiber 2017; Proctor 2014; Beder 2006). This is underpinned by principles such as participation and equity which have been developed within disciplines such as environmental management to increase the sharing of knowledge and collaboration amongst stakeholders (Lewis and Maslin 2018; Feil and Schreiber 2017; Mulvihill and Harris Ali 2017; Beder 2006). This requires an approach which supports increasing intragenerational prosperity and quality of life but also undertakes a restorative approach to safeguard intra and inter-generational needs (Mulvihill and Harris Ali 2017; Beder 2006).
In terms of its acceptance as an issue which needs addressing by government, business and societal stakeholders, sustainability has become increasingly institutionalised within these areas and have shaped different behaviours and decision-making to a greater degree (Lewis and Maslin 2018; Mulvihill and Harris Ali 2017; Geissdoerfer et al 2017).
2.2 The Circular Economy
The Circular Economy has gained increased levels of attention through the work and support of institutions such as the European Union and the Ellen MacArthur Foundation (European Union [EU] 2019; Ellen MacArthur Foundation 2017a). The concept of the Circular Economy and its application to production and consumption processes has developed to include different features from a range of concepts which include the shift to a closed loop system (Moreno et al 2016; Braungart and McDonough 2009). The range of theories relating to the circular economy include the shift from the cradle-to-grave to the cradle-to-cradle approach (Braung
