Sustainable Consumption: Conceptualization and Characterization of the Complexity of “Being” a Sustainable Consumer—A Systematic Review of the Scientific Literature

Abstract

Sustainable consumption is a key concept in society and the environment due to its direct relationship with sustainable development; its importance lies in the decoupling of consumption and economic growth with environmental damage and its involvement with various behavioral disciplines and ecological concepts. Therefore, this research aims to analyze scientific articles linked to key perspectives of the concept under discussion. Due to the scope of the objective of systematizing the existing scientific literature on sustainable consumption in Scopus and Web of Science, a systematic review was carried out, including 104 scientific articles considering criteria that respond to the questions posed. It is concluded that sustainable consumption is a complex and nebulous concept whose theoretical fragmentation gives it breadth but generates overlapping concepts. Likewise, the link between the consumer and the circular economy and the difficulties behind such interaction was denoted. The complexity of being a green consumer in current times and the aspects that comprise it were also covered, and the importance, role, and tools of the government in sustainable consumption. Thus, it is expected to generate a consistent theoretical framework facilitating the creation of new applied research, considering the perspectives highlighted through this analysis.

1. Introduction

In the last three decades, sustainable consumption and production have been attracting increasing interest from scholars and practitioners, as they are considered essential for sustainable development [1,2,3,4]. There is a consensus that the current economic system is intolerable for the global ecosystem [5]. Today, although consumption is the cornerstone of economic growth, it is also the cause of the depletion of non-renewable resources and pollution, representing an overload for the natural environment [6].

The need for drastic and urgent changes is present in the 2030 Agenda for sustainable development [7], which includes the involvement of governments, considering their capacity to create directives engaging the consumer in the sustainability paradigm [8]. It is said that we should consume one-fifth of what we currently consume; nevertheless, the economy and the industry promote and encourage an increase in consumption [5], and even such a fact seems to have been increased by the COVID-19 crisis. Given this, the alternative of sustainable consumption (SC) is becoming more relevant, mainly because of its implication in the consumption of today’s society [4] and various environmental problems [9]. Although the literature tells that such problems are becoming more relevant to people [10], the current market does not favor their proliferation or solution [11,12], although changes are already beginning to occur in the consumer in favor of the adoption of the circular economy (CE) [13], strongly linked with SC [14].

In addition to the aforementioned problems, this research is sustained under the following aspects: the lack of a consolidated conceptualization of SC in the scientific community [11,15,16,17,18], the need to synthesize concepts of SC from various overlapping disciplines [17], the incidence of an extraordinary event, such as the COVID-19 pandemic, on the term under discussion [5,15,19,20,21,22], its linkage with a concept of growing relevance, such as CE [14,23], its ascending importance in the community [3], and its ascending importance in the community [1].

There are some systematic reviews and bibliometric analyses that have developed the concept of SC. Ref. [17] highlight the growing trend of SC, providing their contribution by proposing a mindful consumption model that encompasses various sustainable consumption behaviors. Ref. [24] presents a holistic overview of SC that reveals its inconsistencies and study perspectives, while [25] analyze factors affecting sustainable consumers.

Previous reviews provide an overview of SC, supporting the main objective of this document: systematize the existing scientific literature on SC in Scopus and WoS and to develop four main research questions that aim to address congruently the problems described: RQ1: How is SC conceptualized, and what does it encompass? RQ2: What is the link between the CE and SC? RQ3: What are the difficulties for the consumer in SC? and RQ4: How does or should the government act in SC?

The document is structured as follows: Section 2 presents the methodological aspects of the research, comprising the methodological selection and the procedure behind the execution of the text; Section 3 covers the descriptive and narrative results, presenting graphs of the systematized articles and their ideas linked to the research questions. Finally, Section 4 contains the discussion and conclusions, with an analysis based on the ideas extracted, considering the research questions, and pointing out possible lines of research, the importance of this document, and its limitations.

2. Materials and Methods

This paper is developed under a systematic literature review, which is a research method to synthesize the knowledge of a given field to establish new research topics, and to answer or raise questions that cannot be addressed by individual or empirical studies [26]; its main virtue comes from its capacity to summarize, analyze, and discuss scientific literature to answer a research question rigorously and transparently [27]. Such aspects are in line with [17], who consider that systematic reviews are key to consolidating the various conceptual advances in SC. To conduct consistent, rigorous, replicable, and transparent research, this study followed the three stages suggested by [28]: (1) research planning, (2) conducting the review, and (3) systematized reporting and dissemination. Similarly, aspects of the PRISMA 2020 methodology were considered to ensure replicability, transparency, and scientific rigor [26].

The systematic review was performed in the following databases: Scopus and Web of Science, selected for their multidisciplinary nature [29], prestige [30], and breadth [31].

Following the recommendations of [30], a preliminary search was conducted to identify keywords (“sustainable consum*”, “responsible consum*”, “circular economy”, “green consum*” and “government”) and relevant search strings to answer the research objectives. After correcting any syntax errors in the search strategies, the review was carried out (see

Table 1. Information source and search strategy.

Topic	Database	Advanced Search Strategy	Results	Date
Sustainable Consumption/Circular Economy	Scopus	TITLE-ABS-KEY(“sustainable consum*” OR “responsible consum*” AND “circular economy”) AND (LIMIT-TO (DOCTYPE,”ar”) OR LIMIT-TO (DOCTYPE,”re”))	185	8 November 2022
	Web of Science	(ALL=((“Responsible consum*” OR “Sustainable consum*”) AND “Circular Economy”)) AND (DT==(“ARTICLE” OR “REVIEW”))	270	10 November 2022
Sustainable Consumer	Scopus	TITLE-ABS-KEY (“green behav*” OR “green consum*” OR “environmental attitu*” AND “sustainable consum*” OR “responsible consum*”) AND (LIMIT-TO (DOCTYPE, “ar”) OR LIMIT-TO (DOCTYPE, “re”))	170	10 November 2022
	Web of Science	ALL=((“responsible consum*” OR “sustainable consum*”) AND (“green behaviour” OR “green consum*” OR “environmental attitude”)) AND (DT==(“ARTICLE” OR “REVIEW”))	260	10 November 2022
Goverment/Sustainable Consumption	Scopus	TITLE-ABS-KEY (“public polic*” OR “government*” OR “law” OR “regular*” AND “sustainable consum*” OR “responsible consum*”) AND (LIMIT-TO (DOCTYPE,”ar”) OR LIMIT-TO (DOCTYPE,”re”))	224	10 November 2022
	Web of Science	ALL=((“responsible consum*” OR “sustainable consum*”) AND (“public polic*” OR “government*” OR “law” OR “regular*”)) AND (DT==(“ARTICLE” OR “REVIEW”))	257	10 November 2022

).

Inclusion and Exclusion Criteria

To develop a replicable and transparent research work, the document was developed under the PRISMA 2020 methodology (Figure 1), disclosing the search strings and their date, and the results obtained (assuming the obvious variations in the results). In parallel, inclusion and exclusion criteria were applied according to the research objectives. It should be noted that no temporality criteria were selected, seeking to address a wide range of quality literature. In addition, in the case of perceiving very similar approaches or ideas, it was avoided to extend the text unnecessarily, knowing that readability is fundamental for the understanding and dissemination of knowledge [32,33].

Inclusion criteria:

• IC1: Journal articles and reviews;
• IC2: The document was full text accessible;
• IC3: The study was related to SC;
• IC4: The study brought ideas about consumer/circular economy/government in SC.

Exclusion criteria:

• EX1: The study was duplicated;
• EX2: The study was not completely related to RQ;
• EX3: The study was not full-text accessible;
• EX4: The study had redundant ideas;
• EX5: The study was written neither in English nor in Spanish.

3. Results

This review consists of 98 systematized articles,

Table 2. Distributions of publications by academic journals.

Scientific Journal	Number of Articles	SJR (2021)	JIF (2021)
Sustainability	13	0.66	3.889
Journal of Cleaner Production	13	1.92	11.072
International Journal of Consumer Studies	5	0.99	7.096
Business Strategy and the Environment	4	2.24	10.801
Journal of Business Ethics	3	2.44	6.331
Journal of International Consumer Marketing	3	0.65	-
Sustainable Development	3	1.32	8.562
Resources, Conservation, and Recycling	2	2.59	13.716
Environment, Development, and Sustainability	2	0.68	4.080
Journal of Business Research	2	2.32	10.969
Journal of Public Policy and Marketing	2	1.19	6.435
Journal of Consumer Policy	2	0.7	-
Young Consumers	2	0.62	-
Journal of Marketing Management	2	1.24	4.707
Others	35	Others	35

shows the scientific journals that contributed the most to this work. Among the five most outstanding contributors are Sustainability (18 publications), Journal of Cleaner Production (13 publications), International Journal of Consumer Studies (5 publications), Business Strategy and the Environment (4 publications), and Journal of Business Ethics (3 publications). At the same time, its impact index on Scopus and WoS (SJR/JIF) databases stands out. Among the journals with the highest index are the Journal of Cleaner Production (1.92/11.072), Business Strategy and the Environment (2.24/10.801), Journal of Business Ethics (2.44/6.331), Resources, Conservation and Recycling (2.59/13.716), and Journal of Business Research (2.32/10.969).

Figure 2 shows the distribution by year of the systematized articles. It is highlighted that most of the articles are from the years 2022 (19 publications), 2021 (15 publications), 2020 (12 publications), 2019 (8 publications), and 2018 (10 publications).

As shown in

Table 3. Distribution of publications by research institution.

Institutions	Scientific Articles
Aalborg University	3
University of Sheffield	3
Lund University	3
University of Otago	3
Universidade da Amazônia	2
Sapienza University of Rome	2
National Economics University	2
Victoria University of Wellington	2
Robert Gordon University	2
Universidad Politécnica de Madrid	2
Nankai University	2
Swedish University of Agricultural Sciences	2
Norwegian University of Science and Technology	2
Rajiv Gandhi Institute of Petroleum Technology	2
University Fernando Pessoa	2
Others	173
Total	207

, the systematized literature has been developed by various institutions around the world. The most recurrent research entities include Aalborg University of Denmark (3 publications), the University of Sheffield of the United Kingdom (3 publications), Lund University of Sweden (3 publications), and the University of Otago of New Zealand (3 publications).

Regarding countries,

Table 4. Distribution of articles by countries.

Institutions	Scientific Articles
China	11
Spain	10
UK	10
Germany	9
France	8
USA	8
Italy	8
India	8
Sweden	6
Brazil	6
New Zealand	5
Ireland	4
Denmark	4
Greece	3
Canada	3
Australia	3
Chile	3
Vietnam	3
Netherlands	3
Austria	3
Finland	3
Norway	2
Slovenia	2
Portugal	2
Poland	2
Malaysia	2
Thailand	2
Others	12

shows that China is the main contributor with 11 publications, followed by Spain and the United Kingdom with 10, respectively, Germany with 9, and France, Italy, the United States, and India with 8, respectively. The notable presence of China in sustainability issues may be due to its growing concern for the environmental problems faced by the Asian country [34].

As can be seen in

Table 5. Distribution of articles by method.

Methods	Scientific Articles
Quantitative	47
Qualitative	39
Mixed	7
Total	93

, the methodology is predominantly quantitative (48 publications), followed closely by qualitative with 43 publications, then by the mixed approach with 7 publications. A significant amount of qualitative research that theoretically discusses SC and related concepts stands out, and this is due to the theoretical breadth of the topic to be addressed.

3.1. Conceptualization and Characterization of the Category “Sustainable Consumption”

Formally, the concept of sustainable consumption and production was born at the 1992 World Summit on Sustainable Development, seeking to address sustainability challenges [35] and linking consumption with sustainable development [36]. In 1994, the Norwegian Ministry of the Environment provided the most cited definition (

Table 6. The most cited concept of SC (provided by the Oslo Symposium).

Paper(s)	Main Conceptualization	Key Aspects
[3,6,15,35,37,38]	“The use of services and related products, which respond to basic needs and bring a better quality of life while minimizing the use of natural resources and toxic materials as well as the emissions of waste and pollutants over the life cycle of the service or product so as not to jeopardize the needs of further generations”	Resource Efficiency Intergenerational

): SC implies the use of services and products that meet both needs and improvement of the quality of life while reducing environmental impact so as not to endanger the well-being of future generations [3,6,15,35,37,38].

In the vision of [39], the conceptualization of SC can be seen as a part of sustainable development, as the previously mentioned definition, or as a term that brings together key characteristics revolving around the satisfaction of needs, improvement of quality of life, resource efficiency, minimization of waste, the extension of shelf life [9] or the need for changes in consumption patterns [9,12,17,20]. In other words, it brings together concepts linked to environmentally friendly behavior in the context of the acquisition of products and services [40]. According to [41], SC should no longer mean voluntary abstention from consumption choices (created in the linear paradigm) but the ability to maintain or improve a high quality of life despite the lower resource availability.

Despite the above-mentioned conceptualizations, there are criticisms due to the conceptual vagueness of SC or sustainability [17,42]. It is said that there is no generalized definition widely accepted by the scientific community [11,15,16,17,18,20]. The obstacles that prevent consensus are rooted in its conceptual complexity and the nature of its application. Some of these may be: SC subjectivity that may have a different meaning for each person, i.e., it may involve buying organic food, recycling, opting for environmentally friendly means of transport or other eco-friendly behaviors [6], the heterogeneity of parallel research streams (responsible—ethical—green consumption, etc.) that generate both greater breadth and vagueness [11], the dichotomy present in its name (sustainability vs. consumption) and the multidisciplinary approach of its base terms [17], the current state of the market that encourages unsustainable consumption patterns and consumerism [11,12], the involvement of consumers and their systemic alterations as actors of social change interacting with the environment [12,43], the conjunction of individuals and entities of different levels in decision-making [44], or the need to consider alterations caused by disruptive agents in future consumption patterns [16]. In light of everything that has been said, it becomes clear that sustainable consumption can have different conceptualizations (

Table 7. Summary of literature about extracted ideas of SC.

Paper	Year	Main Ideas	Key Aspect(s)
[3]	2015	SC encompasses factors that go beyond individual behavior and can be observed through international studies that demonstrate how SC varies across different countries.	Flexible/Adaptable
[37]	2022	SC requires a joint effort between individuals and companies. While individuals adhere to the principles of SC, organizations must strive to achieve sustainable production.	Collaborative
[39]	2018	SC is a term with diverse conceptualizations, ranging from being an essential part of sustainable development as proposed by the Oslo Symposium (the most predominant option) to meeting needs, improving quality of life, resource efficiency, and social equity, among others.	Umbrella Term
[9]	2018	SC is a contested concept that revolves around the interaction between social needs and ecological problems, which can be generalized into issues, such as environmental protection, human needs, extending product life cycles, and so on.	Contested Holistic
[12]	2012	SC is a concept that highlights the holistic implications of human consumption, indicating how each decision in consumption can generate an impact (positive or negative) on the global ecosystem. This may involve a change that can be voluntary, be limited by social structure, or consider both factors.	Holistic Voluntary, situational, or both
[17]	2022	SC is a compound term consisting of two words that are antithetical in nature: “sustainable,” which promotes preservation, discourages waste and destruction, and “consumption,” which tends to result in destruction and wastefulness	Contradictory
[20]	2022	The definition of SC is constantly debated among scholars. For some, it may imply recommendations for improving production processes, while others associate it with greening markets or advocating for a sustainable lifestyle. The latter is something that consumers can learn and cultivate, making it a practice where individuals demonstrate their concern for sustainability and have the time and economic resources to do so. In general, SC is seen as an umbrella term that encompasses various aspects of sustainability.	Nebulous Umbrella Term Learnable
[41]	2014	The notion of SC revolves around the need for change, recognizing that humanity is transitioning from a period of “abundance” to one of “austerity”. This does not necessarily mean voluntarily giving up current consumption choices but rather the capacity to lead a fulfilling life with a similar or higher quality of life, despite a decrease in resource availability.	Efficiency Frugality
[42]	2003	The concept of SC is subject to various definitions and, as such, is widely debated and criticized, though its own vagueness can be a benefit. This characteristic provides it with flexibility, enabling it to be adapted to any environment. In other words, it conveys a general idea that acquires more precise characteristics when situated in a specific scenario.	Nebulous Flexible/Adaptable
[11]	2021	SC is the microeconomic foundation on which the circular paradigm is built. Simply put, it is a prerequisite for the applicability of the circular economy because a successful transition towards a circular economy requires adapting more SC patterns.	Requirement to Circular Economy
[18]	2015	SC refers to a change in consumption patterns in such a way that energy and resource efficiency prevail in the household, minimizing waste and adopting SC patterns.	Behavioral Change
[6]	2010	Currently, SC not only entails responsible use of resources and not compromising the development of future generations, but it also encompasses social aspects, such as worker well-being, respect for traditions, animal rights, women and children’s welfare, and social cohesion. SC means different things to different people, such as buying organic food, using public transportation, recycling, supporting a social cause, and so on.	Holistic Flexible/Adaptable
[43]	2017	In general, SC is viewed as a way to reduce the environmental impact of a product throughout its lifecycle; therefore, it takes into account the lifecycle regarding the purchase, use, treatment, and disposal of products.	Through product life cycle
[44]	2019	SC is an amalgam of individuals, marketers, and holistic levels of decision-making aimed at improving the quality of life using fewer resources, and creating lifestyles aligned with sustainable development.	Collaborative Complex
[45]	2019	SC is a broad collective term that designates various consumer behaviors and consumption patterns based on ecological and social needs.	Holistic
[46]	2019	SC is a term that encompasses both green consumption and moderate consumption, which involves using principles of reuse and reduction, and encouraging consumers to use sustainable products, paying attention to how they are reused or disposed of, and giving greater attention to advocating for social and environmental causes.	Umbrella term Transformative Through product life cycle
[47]	2009	To some extent, SC may involve sustainable values, norms, and aspirations that do not necessarily imply ecological purchases, but may impact more prosaic values such as money and time invested in the search for a purchase, or external aspects that escape the consumer’s control.	Emotional Rational Situational
[22]	2022	In times of crisis, where there is panic and social anxiety, changes in consumption patterns usually occur, and in the context of SC, this can lead to impulsive purchases and overall waste.	Crisis Susceptibility

), depending in many cases on the perceptions of the authors, the purpose of the study, and the contexts in which the phenomenon occurs, among others.

Both the conceptual complexity and breadth of SC are given from the links with related terms, such as responsible consumption, ethical consumption, anti-consumption, mindful consumption [17], or green consumption [45], highlighting the differences between these concepts. For example, according to [48], the difference between green consumption and ethical consumption is that the former focuses only on the environmental factor, while the latter integrates social factors. In another case, the difference between anti-consumption and mindful consumption is also observed. The former is the voluntary choice to avoid waste due to a thrifty (but not environmentally conscious) personality, deriving pleasure in not spending, or the desire to lead a simple life considering non-materialistic factors, although it may integrate an environmental concern [49], while the latter invites reflection in consumption, replacing hedonic values and prioritizing benevolent behaviors that reduce impulsive, compulsive or addictive purchases [17]. Similarly, SC is based on the 3Rs [reduce, reuse, and recycle] [6,9], being a guide that makes up the shared action of circular behavior [50] while finding conceptual similarities in its environmental nature with green consumption [45,48].

It should be noted that sustainable consumption and production have two compounds, and there are discrepancies as to how they should be approached. Ref. [51] points out that sustainable production is subject to SC, although he also states that both terms can be approached jointly or separately. On the other hand, Ref. [46] considers that SC depends on sustainable production, intuiting that products should be conceived under the circular paradigm so that both concepts should be approached as a whole. From another perspective, sustainable consumption and production are considered to interact with each other, where the consumer has a vital role in the former and little direct influence on production [20], which actively involves business and government.

The fact is that regardless of how it is approached, SC is quite broad since a large number of factors influence how it performs. Omitting the already influential demographic characteristics, aspects, such as religion [52,53], parental environmental values and family upbringing [54], culture [3], corporate irresponsibility [55], consumer associations [56], informed consumer and information availability [38], or the green consumer value-action/intention-behavior gap [47,57,58], to mention a few, are aspects that add layers of complexity to a term that is already difficult to define.

At a recent juncture, the COVID-19 pandemic has brought about changes in consumers, and economic problems. It is argued that the pandemic prompted changes in sustainable behavior, generating greater environmental awareness subject to sociodemographic characteristics [19], although, by itself, it does not appear to have the potential to change current consumption paradigms [20]. Despite having tentatively generated changes in favor of SC, such as the reduction in purchases of “frivolous” products [21], irresponsible behaviors linked to panic buying and unnecessary accumulation of products have occurred [15,20]; however, such attitudes are related to a natural reflex of human beings in a crisis. From the perspective of [22], the problems caused by the pandemic have led to impulsive and hasty purchases linked to the excessive use of credit cards, going totally against SC.

3.2. The “Symbiotic” Relationship between Sustainable Consumption/Consumers and Circular Economy

In essence, CE focuses on the extension of the shelf life of a product after its first life cycle [59], has a disruptive capacity that integrates concepts related to the interests of SC [11,17], having an impact [11,46] on the three main actors (consumers, governments, and corporations) that influence sustainability in consumption and production issues [60], which implies its capacity to generate socio-environmental changes in both the private and public sectors [11]. For all these reasons, its capacity to sustain and accelerate the development of sustainable consumption and production [61,62,63] is denoted, highlighting at the same time how it reliably integrates the paradigm of economic growth without undermining environmental well-being [64], which implicitly includes a cross-sectional vision that not only benefits SDG 12 but also several others [63,65].

The literature on CE tends to focus on the private sector, emphasizing sustainable business models while neglecting the necessary changes in the consumer to accept such scenarios [66]. It should be kept in mind that consumers perform a fundamental role in both the adoption of CE [11,36] and SC [12,20,43], being both concepts linked by the implications of the former, which demands an abrupt change in consumption values, patterns, and relationships [66], and encompass the idea of resource optimization, low-emission production, product efficiency, and gradual transition to green consumption [46].

Although various sustainable development practitioners focus on reducing the use of virgin materials at the production level, changes in this area are slow [67]. Given this, the consumer is key to achieving and accelerating the shift from a linear to a circular economy [68]. Its approval is a significant generator of change for current organizations [36], pointing out how the idea of generating changes at the behavioral level would allow for reducing the paradigm of “consume and throw,”, i.e., through the conception of multiple ownership of products, a closed loop is created that maximizes the use of resources while reducing waste [67]. According to the research by [69], consumers have a fundamental role that they do not usually perform, as they do not have a clear understanding of what CE is and how it allows for raising awareness and contributing to sustainable consumption and production. Ref. [68] add that citizens are becoming increasingly aware of their responsibility in consumption cycles, although the latter recognize their lack of understanding of CE.

In the context of CE, consumer behavior implicitly encompasses aspects of SC [50], and consumer intervention can be reflected in the basic concept of the 3Rs [6] and its variants [50]. In other words, the consumer has a sustainable behavior when repairing, extending the shelf life of the product even considering the implicit design limitations [70], how difficult it is to allocate time to repair, and how easy it is to purchase a new product online [71]; recycling, sending products to a treatment process so that their materials serve as raw material for new materials or products, contemplating the differences in product categories and the type of recycling of these [72]; rethinking/reusing, considering the financial and social benefits of renting or buying second-hand products [45,73,74]; refurbishing a product, understood as improving the functional performance of an item (e.g., laptop), to keep it updated [75]; or remanufacturing, which involves the producer restores the product preserving its original function and added value [76]. Ref. [50] expands on this by expressing how the 9Rs framework interacts with CE (

Table 8. The consumer and the circular economy within the 9Rs framework.

Approach	Strategy	Actions
Intelligent use of products and manufacturing	R0. Refuse	Making the product redundant by abandoning its function or offering the same one with a radically different product.
	R1. Rethink	Finding or formulating new ways to use a product.
	R2. Reduce	Increasing efficiency in the manufacture or use of products.
Extension of product and component shelf life	R3. Reuse	Reusing a product that has been discarded by another consumer, provided it is in good condition and fulfills its original function.
	R4. Repair	Repairing and maintaining a defective product so that it can regain its original function.
	R5. Refurbish	Refurbishing an old product and bringing it up to or near current standards.
	R6. Remanufacture	Using the parts of a discarded product in a new product with the same function.
	R7. Repurpose	Using a discarded product or its parts in a product with a different function.
A useful application of materials	R8. Recycle	Processing materials to generate resources of equal or lesser quality.
	R9. Recover	Incineration of waste for energy generation.

Source: [50], those referred to in [77].

).

3.3. The Complexity of “Being” a Sustainable Consumer

Although consumers are essential agents in SC, and their influence is conditioned by variables that can define their actions [6], their behavior causes many environmental problems [78]. Two very particular barriers affect or discourage the reduction in consumerism: habits and psychological/social needs [79]. As consumerism is already an inherent part of everyday life, individuals are accustomed to consuming/wasting resources in their daily activities in a natural way, so a change represents the allocation of time and effort [12,79]. Changes depend on consumers’ practices since they must be carried out to become a habit. Therefore, apart from educating and raising awareness, some authors believe that to generate effective variations, it is necessary to create sustainable practices in the lifestyle of the subjects [67], implying the intervention of the State through political measures that generate changes at the individual or collective level [80], although, similar to consumers, the government does not seem to be willing to assume radical changes [51].

It is known that the social nature of human beings prompts them to imitate characteristics or attitudes that are acceptable in the closest social group; the desire to integrate, avoid rejection, ridicule, or loss of social prestige are often factors behind imitation [81]. In most affluent societies, consumption is not focused on the satisfaction of physical needs but on the social and psychological ones [79], as these often represent or build the identity of individuals while allowing them to achieve a prominent place among their peers [60]. On many occasions, being a good person does not imply being a good consumer because, although ethical, social, or environmental traits may exist in the personality, individuals may believe that their consumption should not necessarily reflect such aspects [82], probably because it implies restrictions that infringe their individual freedom [48]. For the same reason, they may have sustainable values that tentatively drive a related behavior [83], but, in the end, they omit such values, perhaps because they do not perceive an immediate change or feel that their individual effort is in vain [48], giving rise to the value-action gap.

In contrast, ecological social norms are usually irrelevant [48], which represents a difficulty when influencing peer behavior, even worse if the inability to visualize concrete effects of pro-environmental actions and the difficulty of assuming a new lifestyle are taken into consideration [48]. The ecological concern is widespread, and consumers tend to be in favor; however, this is not always translated into real SC behaviors [6,57]. Although there are altruistic consumers [84], they are often attributed with selfish values (focused on social status or the self) [85], i.e., they will join the ecological paradigm once they begin to be directly harmed by environmental problems [86] or if they perceive that it gives them higher social status [85]. The fact is that in today’s world, with a routine conditioned by technology and social prestige, where mobile devices have allowed access to applications with hedonic (fun, pleasure, or entertainment) and utilitarian characteristics [87], where it is easier to buy (even more so with smartphones) than to repair a product [70] and the novelty is a relevant purchase driver in items visible to our peers [71], the current situation openly encourages unsustainable consumption patterns [11].

Moreover, the seriousness and dull attitude attributed to sustainable behavior are not attractive or easy to take on for many individuals [48]; in some cases, it requires facing higher nominal or real costs [82], falling into cognitive dissonance for acquiring a product/service that goes against our green values (i.e., traveling by plane constantly) [88], dealing with nebulous and biased green marketing initiatives [48], arguing with detractors of green stimuli [86], dealing with complex purchasing situations due to logistical (i.e., unavailability of products or lack of green alternatives) or emotional (i.e., sense of responsibility) barriers [48], and the implicit difficulty of performing sustainable practices that demand time and effort [71]. Therefore, being sustainable often means swimming against the tide.

As a result of all the above, the complexity of human behavior is emphasized. Ref. [89] agrees with this by mentioning that there are at least 80 theories of behavior in different sciences of the subject (sociology, anthropology, psychology, and economics). This affirmation can be sustained by knowing the enormous amount of variables that affect the sustainable behavior of subjects, among which are: gender [6,15,90,91,92], age [6], personality [48,93,94,95,96], income [83,92,97,98,99], access to information and analytical skills [2,38,82,100], family [54,101], society and its agents [55,56,79,81,102,103], technology and digital opinion [87,104], values [83], culture [3,67,105,106,107], marketing initiatives [48], religion [52,53], physical activity [108], or crises, such as the COVID-19 pandemic [15,20,22], to mention a few. It highlights how even aspects linked to the perception of masculinity (of men and women) and links between sustainability and femininity affect the ecological behavior of certain men [109] or how some subjects consider the adoption of pro-environmental behaviors as something boring that seeks to sermonize consumers, in such a way that it infringes individual freedom [48].

3.4. Governance and Sustainable Consumer

The approach to SC by governments is a difficult task; it involves questioning consumption and its subsequent economic growth while “infringing” the consumer’s “freedom of choice” [39]. Although SC focuses on the individual’s ability to change his or her consumption habits, the State is empowered to generate sustainable public policies that generate changes in individual and collective behavior [80]. In this idea, the former is the main agent of SC; however, the government provides the directives to be followed to achieve the objective [46], being an important asset when it is developed in the form of environmental governance [98].

In many cases, governments create policies and strategies that reduce waste and externalities in different contexts [14]. Similarly, they incentivize CE, and this, through the changes generated, SC [14]. Although consumers are more likely to adopt pro-environmental behaviors through their referents [81], governments generate the commitment between consumers and the sustainability paradigm [8], highlighting their vital role in the achievement of SC.

However, concretely, what can policymakers do to promote SC? (

Table 9. Approaches to government intervention.

Approaches	Details
Legislation	Subsidies Taxes Laws Regulations Corporate environmental reporting
Education	Develop consumers’ environmental awareness Labeling Information Transparency
Behavioral	Nudge Theory Social Tippin

Source: Own elaboration based on [111].

). According to Ref. [51], it is possible to develop SC from two main pathways: legislative pressure and education. Legislative pressure implies public provisions that favor SC; for example, subsidies and incentives, such as money or tax reduction, provide economic benefits that represent a greater tendency to sustainable product choices [110,111,112]. Within this scope, the need to remove or reduce subsidies to non-sustainable products is also pointed out [51]; taxation of non-sustainable products is also an effective way to influence consumer choices [51,110,111,112], especially when the financial benefit is significant for the user. Finally, laws and regulations, with special emphasis on production, provide public provisions focused on resource optimization and waste reduction [110,111]. For example, the proposed legislation that provides the “right to repair” includes how the producer entity must facilitate and support the repair of the product from its design, in addition to offering the necessary tools for this purpose, considering that without the intervention of the supplier, the repair would be financially unviable [70].

Even though the strict compliance with and use of these tools represents a benefit to the ecosystem, various political agents and industry lobbyists intervene in many areas of it [112]. An example of this can be seen in the implications behind programmed obsolescence, which can even be transferred to a circular ecosystem through an exaggerated rate of refills, implying a deliberate manipulation to shape an unsustainable business model within CE [113].

On the other hand, education is an approach whose importance encompasses sustainable development as a whole, highlighting its greater incidence when applied from an early age [114]; it implies the provision of transparent information for the predilection of SC [51], and the environmental awareness of the consumer [110,112]. This involves the government should force companies to openly report their practices, processes, and values, ensuring that these promote sustainability [110,112]. At the same time, it should promote responsible labeling, considering that consumers favor products that show both their social and environmental commitment, which supports ecological education and favors the decision to buy sustainably. In general, the public entity should require industry to communicate the environmental implications of its products or services [110,112,115], especially in developed countries, where electric utilities and industry are the largest emitters of greenhouse gases [112].

Alternatively, using knowledge from behavioral sciences and considering the importance of the social domain in consumers [81], governments may opt to apply nudge theory, consisting of the intentional change of the architecture chosen, to guide an individual or group to make sustainable decisions voluntarily, facilitating the creation of effective public policies in the generation of sustainable behaviors [116]. The application of this concept depends on the context to be addressed, with four tools: simplification and framing of information, changes in the physical environment, changes in the default policy, and use of social norms.

Another social strategy is social tipping, which implies a phenomenon that can generate a little change in a parameter of the social system, having the capacity to create an abrupt change in the system through feedback [117]. It is possible to visualize an example in the quasi-experimental research of the above-mentioned author, where the ecological problem occurs in the increased use of single-use paper cups versus a reusable cup (a more sustainable option but with the inconvenience of having to return the object after each use). Due to the placement of a sign on the counter with the phrase “Use mugs instead of paper cups, for the sake of the environment” and the subsequent feedback that was updated every week, it was possible to obtain favorable results that increased the use of reusable cups. Nevertheless, the same author argues that it is possible that this strategy can both encourage and hinder the adoption of sustainable behaviors in unfavorable scenarios; therefore, this author recommends caution.

4. Discussion

4.1. Sustainable Consumption: A Discussed, “Simple” but Flexible Term

Through the review, it has been noted that SC has different interpretations, which give it a certain theoretical complexity (Figure 3). It is made clear that there is still no consensus regarding its definition (although that of the Oslo symposium is the most cited). However, it is also emphasized that this may not necessarily represent a disadvantage but a benefit [42].

Certainly, the different interpretations of SC reinforce the idea that it is a concept with a simple general idea, and this allows it to adapt to different interpretations that are linked to situational aspects or the perception of individuals. The truth is that, according to this research, SC is an umbrella concept that involves various terms of sustainability and adds a social dimension to it. Its main idea is the acquisition of sustainable purchasing behavior, the contribution of the consumer in the closed loop of the circular economy, optimization of natural resources, preservation of the environment, and improvement of quality of life. It has three key aspects:

• The comprehensive change of the consumer toward sustainable (ecological and social) patterns;
• The combination of responsible, thoughtful, ecological, and ethical purchasing behaviors;
• The situational influence for achieving SC and its interconnection with various terms of sustainability.

In summary, SC is a simple term to understand but difficult to apply and internalize [17,118]. Its links with a wide variety of related concepts and the variables that condition or enhance its understanding or implementation have not yet been consolidated in the scientific literature. The fact is that, as a result of the analysis carried out, it is possible to emphasize the need to address the concept with an approach that, although it is multidisciplinary, is necessary to approach it synthetically [119], focusing on specific contexts, concepts, and relationships, considering possible interactions with other phenomena. In other words, as it is a concept that concentrates variables from different disciplines, it is necessary to simplify it to create knowledge in particular scenarios that can later be taken to similar scenarios or more complex panoramas, seeking to achieve greater methodological generalization.

4.2. Sustainable Consumption as a Requirement for Circular Economy

In recent years, CE has become a topic of great interest to the scientific community [23], possibly because of its cross-disciplinary disruptive capacity that integrates several SDGs [63,65]. Regarding this research, its linkage with sustainable consumption and production have become evident, as it integrally encompasses the term under discussion in many of its areas. It should be noted that the literature on CE tends to focus on the productive sphere [66], neglecting the consumer even though this is a determining factor in the shift from the linear to the circular economy as it is the consumer who must change and spend part of his or her time on activities that really generate the closed loop of the circular paradigm, besides encouraging organizations through consumption. In the ideal scenario (Figure 4), consumers adopt sustainable values and patterns, which entails demanding products and services that meet their new expectations as long as convenience is taken into account. This requires the existence of infrastructure (e.g., logistics) that enables consumers to access products and services born from the circular economy, and to engage in activities that facilitate the closed-loop process without causing inconvenience or hassle (e.g., time or money).

A concrete analysis of the interaction of the sustainable consumer with key aspects of CE is required. For example, it is not very useful to sell a product made from recycled materials if consumers are not willing to buy them [72]; therefore, it is necessary to scientifically investigate the factors that condition the success of such products, considering geographical, demographic, psychographic variables, among others. In another example, if they perceive remanufactured products as inferior or are unwilling to buy them for a profitable price [76], there would be no real incentive for companies to perform such an action of the circular ecosystem. On the other hand, consumers must have access to the necessary infrastructure and information to join CE; otherwise, they would consider it inconvenient, which may result in a lower frequency of SC practices [120] and a most frequent appearance of the value-action gap.

4.3. Inconsistencies and Difficulties of the Sustainable Consumer in an Unsustainable System

As can be assumed, consumers perform a fundamental role in sustainability in general; however, their involvement is full of inconsistencies. For example, in the research by [6], it was evidenced that 4 out of 5 consumers recognize the importance of climate change, but only 1 out of 5 is willing to assume the necessary changes to mitigate such aspects. In contrast, Ref. [121] argues that people with a good ecological attitude are more willing to assume a pro-environmental role. Likewise, it is discussed when consumers tend to assume green behaviors, whether adults [6] or young people [100]; gender is also a variable that shows clear discrepancies. Some authors point out a higher predisposition for women [6,57], while others consider that there is no significant difference in gender [90,91].

Based on the work by Ref. [109], it is possible to make inferences regarding why there is usually no research that indicates a greater predisposition to green behavior in male consumers. The paper points out how the perception of masculinity can be affected by assuming green behavior. The authors indicate how greenness and femininity are cognitively linked, which would explain how, consciously or unconsciously, men can be conditioned by stereotypes imposed by themselves and their female peers; such a statement should be more relevant in macho cultures.

As a result of the documentary analysis, it was possible to observe the different implications and variables that affect consumers and their ecological behavior. It is assumed that there are differences when considering the various methodological aspects of each research, which, to some extent, may mean the creation of a measurement scale adaptable to different contexts to achieve results that are easier to contrast consistently. In parallel, the importance of cross-cultural research stands out, demonstrating the relevance and consistency of this variable [40,87,91,105,107] since it achieves different results despite the similarity in the methodological instrument.

On the other hand, it highlights the complexity of being a green consumer in the current system, which openly favors unsustainable consumption patterns and economically and socially punishes sustainable ones. It is necessary to learn (or relearn) to satisfy our psychological and social needs in a non-material way, implying the creation or linking of identity with actions, characteristics, and values becoming easier than changing habits [79]. Ref. [79] mentions how advances in positive psychology could facilitate an improvement in green consumption behaviors, promoting well-being less linked to wealth and more to non-material aspects, such as relationships and community. While it is true that consumers can (and should) be architects of changes in favor of their ecosystem, the government must get involved to reverse the current scenario, where the message of “being green” is tirelessly repeated, but the necessary tools to be so are not given; therefore, it ends up being inconvenient.

4.4. Governance and Sustainable Consumer. Public Policy: Formative Strategies and Legislation in Debate

Regarding the government, the influence of the public entity on sustainability is both undeniable and complicated. On the one hand, it involves dealing with consumers and their freedom of choice, which, from a negative perspective, could mean manipulation or prohibition. The truth is that environmental problems are pressing; today, the construction of civic values must congruently integrate sustainability, which suggests a process of education that, although it may be simple to apply in the youngest minds [114], requires a change in the lifestyle of today’s adults, which is considered difficult to achieve [79]. Therefore, the legislative pathway and the use of behavioral strategies appear to be appropriate options for promoting ecological change in adult citizens, especially when they are provided with convenience and previous education (although all of this is subject to contrasts).

On the other hand, it is crucial to create policies that entail a real change in organizations (beyond their CSR), i.e., policies that genuinely look after a circular or ecological productive scheme, ignoring the agenda of organizations that prioritize only their economic interests [112]. Certainly, this task requires prudence, as it does not seek to discourage private investment, so it is necessary to research and promote the links between corporate profitability, sustainability, and the market (consumers). The aim of all this is to generate public policies that promote environmental well-being and a financially attractive scenario for companies.

4.5. The Sustainable Consumer as the Central Axis of Change

Consumption and production are aspects that interact with each other but do not involve the same actors, although the opinions of various authors discuss how both terms and their agents should be approached [20,46,51]. The difficulty in determining which actor (consumer/producer/government) should initiate and sustain change is pointed out. In the first instance, it can be said that the government is the main agent; however, lax laws are usually not very transcendent, and severe laws hardly adjust to the market reality (consumer preferences and supplier capacity), while education is a slow and often voluntary path (it depends on the consumer). Apart from the industry and its rhetoric, considering that its main reason to exist is the generation of wealth and recognizing the economic and social contribution they represent, the consumer should really get involved in generating change, being supported by the government, and encouraging the industry. In other words, consumers can shape the industry through their demand, forcing the latter to move towards a scenario of profitability and productivity, and efficiency in terms of environmental well-being. It could be said that this is the ideal scenario in which the government and even academia should intervene. The first should provide consumers with information and facilities to improve their consumption or encourage them to initiate the above-mentioned change. In addition, it must provide tools, benefits, and obligations to the industry to meet the new expectations. The second must provide the necessary knowledge to sustain or support such changes, which may be: the creation of appropriate public policies, ecological improvement in production processes, environmental education management, the new implications of integrated environmental management, the technical requirements of the circular paradigm, sustainable investment, among others.

5. Conclusions

Through the systematic review, it was possible to answer the research questions previously posed. The theoretical breadth of SC was noted, having pointed out a great variety of related concepts that provide knowledge and soundness but also vagueness. Likewise, the presence of its complementary element focused on the productive/entrepreneurial part was highlighted. As a result of both, its explicit integration with CE was born. Concerning the latter, the need for consumer participation and the disjunctions that can be found in the adoption of such a scheme was highlighted. Then, the difficulty of being a green consumer in today’s market, and the enormous number of variables that comprise it, are described. Finally, the role of government is highlighted since it is the entity that provides the directives to be followed by the other two main actors (consumers and industry), also understanding the implications of making such decisions, and the complexity behind each sustainable public policy.

5.1. Theoretical Implications

Through this review, it became evident that there is a widely cited definition of sustainable consumption (SC), although it is often the subject of much discussion. Generally speaking, SC is an umbrella concept with complex characteristics, so defining it precisely and analytically involves attributing values specific to the study scenario and the perceptions of the individual analyzing it. In other words, the conceptual vagueness of SC endows it with interpretive flexibility, which allows it to adapt to different scenarios. However, some degree of uniformity is recommended to study it more precisely. On the other hand, the neglect of the consumer aspect in the circular economy was highlighted, with a greater number of studies focused on the productive part, overlooking the key actor in achieving the circular economy. Likewise, the complexity of analyzing the sustainable consumer was presented, with enormous amounts of variables that make it difficult to analyze, in addition to the hypocrisy of the market, where sustainability is recommended, although this only implies inconvenience. Finally, emphasis is placed on the role of government, which, while defining the laws and rules that consumers and industry must follow, involves a complex decision-making process, interacting with different actors, and evaluating the scenario with clinical precision to avoid being too lax or inflexible.

5.2. Practical Implications

Based on our research findings, there exists a significant opportunity for entrepreneurs in the field of sustainable businesses. The knowledge generated provides a general insight into how to understand the sustainable consumer and the difficulties to be considered. Moreover, it proves advantageous for marketing professionals to understand that sustainability can be interpreted in several ways. Therefore, they should be capable of determining what sustainability means to their customers and which sustainable attributes are dominant in their market to enhance their value proposition. Additionally, our research has revealed tools that can be leveraged by policymakers, along with the complexity involved in every decision and the necessary analysis required to address sustainability-related issues.

5.3. Future Research Directions

The importance of this review is based on the study perspectives highlighted by reading and analyzing 104 high-impact scientific articles in WoS and Scopus. The following perspectives stand out: the theoretical breadth and vagueness of SC, approaches and implications of the three main agents of SC, the educational and technical requirements of the consumer in CE, the consumer as the main agent of change and interaction with the government/CE, the consolidation of a sustainable consumer scale, the linkage between femininity and environmentalism, the problem of the sustainable consumer and the hypocrisy of the current market, social and emotional implications of being sustainable, the role of government in SC and the complexity behind decision-making, the formulation of environmental civility, the profitability of sustainable companies, among others.

Every study has limitations that should be mentioned. As in many other reviews, the research was conducted in Web of Science and Scopus, having ignored any relevant literature not indexed in these databases; conference papers, governmental, or corporate reports that may integrate remarkable ideas for the context of the research have not been considered, besides some articles belonging to certain publishers (i.e., Wiley, Hoboken, NJ, USA) and others were not accessible due to the language barrier (i.e., Korean, Chinese, Polish). Although every effort is made to reduce the subjectivity of the authors by prioritizing articles from high-impact journals, it is possible to assume that the relevant literature from lower-impact scientific journals (or grey literature) has been ignored.

That being said, it is expected to encourage theoretical research on the aforementioned topics, along with empirical investigations that study the sustainable consumer in specific sectors, taking into account possible inconsistencies. Likewise, the need to study what the consumer requires to be sustainable and to adapt to the circular paradigm is highlighted, and the interaction of government policies with sustainability agents. It is necessary to emphasize the need for new systematic research, as the literature is extensive and constantly developing. Those that cover a greater number of databases are particularly encouraged, in addition to considering grey literature.