Sufficiency, Consistency, and Efficiency as a Base for Systemizing Sustainability Measures in Food Supply Chains

Abstract

Due to severe biodiversity and climate crises, there is now a need for sustainable supply chains. Food supply chains contribute to biodiversity loss, especially through land use and agriculture. In addition, energy-intensive storage for refrigeration and intercontinental transportation lead to high emission along chains due to seasonality. Selecting and prioritizing decarbonization actions is a key task for decision makers along food supply chains this decade. Often, modernizing supply chains by integrating information and digital technologies is seen as beneficial for environmental goals. The aim of this work is to develop a new systematization of sustainability measures based on archetypal sustainability strategies (sufficiency, consistency, and efficiency) that support the prioritization and thus the selection of decarbonization measures. Existing measures will be researched through a structured literature review. At the same time, it is recorded how they are categorized or systematized. Forty-eight different systematizations are analyzed. The majority relate to specific sectors and are not generally transferable. Sustainability is often addressed using the triple bottom line. In particular, efficiency and consistency measures are often included in the categories found but are rarely used for systematization. A new systematization of sustainability measures is proposed and applied to a set of digitalization and logistics 4.0 measures using the example of a fresh apple supply chain. The advantages of the proposed systematization are discussed, and further research directions are given. The presented method has not been examined in the literature so far; this concerns both the width and depth of the consideration of supply chains.

1. Introduction

Global crises shape the challenges facing humanity. Climate and biodiversity crises are shaped by humans and must be solved by them [1]. Our economy is essentially driven by fossil fuels and needs to be transformed. On the one hand, production and transport processes contribute to the crisis through their energy demand and emissions, and on the other hand, they suffer from the effects: Heavy rains destroy transport and energy infrastructure [2]. Intense hot spells can also affect infrastructure or even worsen human health [3] and lead to productivity losses [4]. A special focus needs to be put on the food sector, as it is contributing to both these crises. Land system changes are a main contributor to biodiversity losses [5]. The widespread use of agrochemicals consumes energy and fossil reserves and contributes to changes in the nitrogen and phosphorus cycles. These examples provide an idea of how food supply chains lead to multiple risks to our planetary boundaries [6]. Measuring the sustainability of food supply chains necessarily includes the energy and emissions associated with processes along the supply chain (i.e., production, distribution, and storage) [7]. Although agricultural products can often only be harvested seasonally, retailers and distributors seek to offer these products throughout the year. This results in a need for long-term storage or intercontinental transportation, which leads to a high energy demand due to the fuel for transportation vehicles or the operation of refrigerated or controlled atmosphere (CA) storage facilities [8]. Since the policy goal is to reduce emissions to near zero, decarbonizing the economy and basically all SCs is a daunting global task. There are several measures available that need to be selected and prioritized depending on the goals of each organization.

1.1. State of Research

Research on sustainability and carbon footprints in SCs is extensive, and the topic of sustainability in food SCs is well-studied. Many publications focus on green supply chain management (GSCM) and emissions of specific sectors [9,10,11,12], while other publications focus on the application of optimization methods [13,14]. There are several case studies dealing with the carbon footprint of different food types, such as fruits [8,15], vegetables [16], or meat [17]. These studies show the great impact of refrigerated or even CA storage and long-distance transportation on the carbon intensity of the chains.

Another focus of research is food waste reduction [18], which is closely related to lean supply chain management [19]. Food waste occurs at various points in the supply chain: growers sort out fruits and vegetables that do not meet necessary standards and requirements. Losses occur during handling and transportation due to mechanical damage. Even at the point of sale, certain goods spoil because they have a limited shelf life and are not sold quickly enough [20]. The energy already spent on growing, harvesting, processing, transporting, or storing these goods is then lost, lowering the overall efficiency of the food system. Both green and lean supply chain management concepts address the need for sustainability on a macro or meta level.

Regionality is another concept discussed at an aggregate level. Researchers hypothesized that shortening SCs by sourcing more locally or regionally would have a positive impact on sustainability particularly carbon emissions [21,22]. The distribution channel chosen may also have an impact on emissions [23].

Other studies go into more detail, focusing on only one section or aspect of SC. Many different measures are available for maritime transport, ranging from different fuels (hydrogen/ammonia, biofuels) to technical innovations (propeller or hull design) or operational measures (speed reduction, weather routing, hull cleaning) [24]. However, measures need to be considered not only for the means of transport but also for the handling infrastructure, such as ports or terminals [25,26]. Less obviously linked to sustainability issues are communication measures: methods such as product labeling can have a real impact on carbon emissions [27].

Many hopes for the green transformation of our economy are based on technological innovations. A large part is played by the digitization and integration of information technology into processes and networks. The scale of this modernization has increased to the point where it is commonly referred to as the implementation of Industry 4.0 or, with a SC focus, Logistics 4.0. These concepts include various technologies such as artificial intelligence, sensors and Internet of Things, Big Data, cloud services and more. Several others have addressed the potentials and challenges of integrating these technologies into food SCs [28]. It is often emphasized that these technologies are beneficial not only for processes but also for the ecology [29] although quantification of this impact has only been done for a number of technologies [30].

1.2. Research Aims

Sustainability is a broad research area. Different understandings and concepts (weak vs. strong sustainability) sometimes make it vague [31]. This research therefore focuses on decarbonization, as it is more clearly defined [32]. Climate change is arguably the most urgent challenge and additionally drives the biodiversity crisis [5]. Analyzing our world from an SC perspective is a way to acknowledge the complexity of economic systems with globally ramified SC networks and multiple actors at different levels. Sustainability or decarbonization studies often group actions or activities by different categories depending on a particular SC sector or areas. The triple bottom line is often used to systemize sustainability measures. However, it only groups them into categories without prioritization or information about the relationship between each measure. The main objective of this research is to develop a systematization of sustainability and decarbonization measures for SCs. This systematization needs to be at an abstract level so that it can be applied in any SC. It should also support the transformation of SCs by providing recommendations for action. Therefore, it must include a prioritization of actions to start with and provide guidance on where to apply these actions. This way, the systematization can be used as a decision-support system. To test the new systematization, it will be applied with a set of Industry 4.0 technologies in the context of fresh apple SCs.

1.3. Strucuture of the Paper

This introduction provides a brief motivation for the research, the state of the research, and the research aims. The following Section 2 clarifies the key terms and concepts for the work before describing the methodology for the literature review. The main information about the included publications is also provided in Section 2.2. After a quantitative and qualitative analysis of the different systematizations, Section 3.2 presents a new systematization of measures based on the results of Section 3.1 and the basic concepts described in Section 2.1. In Section 4, the newly proposed systematization is applied to an exemplary supply chain, which is then discussed in Section 5. Finally, an outlook on further research activities and a general conclusion are given in Section 6.

2. Methods

This section is divided into two parts: First, a set of definitions is provided to clarify the concepts and terminology used. The second part of this section presents a methodology for a systematic literature review that has been adapted to this research.

2.1. Terminology

The general framework of this thesis is supply chain management (SCM), which is first defined. It is followed by a definition of archetypal sustainability strategies that outlines all available mechanisms to achieve sustainability and reduce emissions.

Supply chain management (SCM) can be defined as “a modern conception for corporate networks for the development of cross-company success potentials by means of the development, design, control and realization of effective and efficient flows of goods, information, money and finance” [33].The tasks of SCM are the strategic design of supply networks, the planning of SC connecting suppliers and customers, and the execution and operation of processes (e.g., warehousing, production, and transportation) [34]. The concepts of GSCM and sustainable SCM (SSCM) focus on the “voluntary integration of economic, environmental and social considerations” into SC, while GSCM focuses only on environmental aspects, and SSCM considers all three sustainability dimensions [35]. Typical topics for SSCM planning, execution or coordination include incentives for sustainable activities, transportation choice management, waste management, SC footprints, compliance measures, or sustainability-oriented benchmarking [36].

Sufficiency, consistency, and efficiency can be defined as archetypal sustainability strategies, as they describe mechanisms to reduce emissions, etc. and increase sustainability [37].

Sufficiency is defined as a material renunciation or reduction [37]. It is based on the idea that technological and efficiency improvements are not sufficient to achieve truly sustainable development [38]. Sufficiency means asking what is really necessary for a good life and focusing on meaningfulness instead of consumption. Transferred to the economic or industrial discussion on sustainability, this could mean defining standards and limits (e.g., EU emission standards) or renouncing export or quantitative growth orientation.

Consistency means aligning material and energy flows with natural processes and shaping them in beneficial rather than harmful ways [37]. The concepts of a circular economy, circular SC, and products are concepts of consistency. The use of renewable energy and resources, the design of material flows in closed loops, or more general circular economy strategies are examples of this strategy [39].

Efficiency means improving the ratio of output to input [37]. It can be applied to different environmental dimensions, such as energy or material/resource efficiency. Eco-efficiency generally means achieving more benefits while maintaining or reducing environmental impacts. Efficiency measures are very important but have two serious shortcomings: First, they only allow relative and rather small improvements, and second, their effectiveness is counteracted by the rebound effect [40].

2.2. Literature Analysis

A systematic literature review (SLR) was conducted to gain a complete image of discussed systematizations of sustainability measures. The function of an SLR is to summarize existing evidence, identify gaps, and provide a framework for new research [41]. The fact that the literature is not likely to be biased and variations of the found categorizations can be studied, justifying the extra effort necessary. A methodology proposed by [41] was applied, which proposes three phases: planning, conducting, and reporting the review.

The planning of the SLR starts with the question of whether an SLR is really necessary. The aim of this research is to collect all available information about the systematization of sustainability measures in the context of SC. There are systematic reviews in the context of sustainability and SC [42,43,44], but as they mostly focus on a certain sector (freight transportation, automotive), it is highly unlikely that they include all relevant studies. Therefore, it is justified to conduct an SLR. This paper poses the following research questions: “How are sustainability measures systemized in the context of SC?”; “Is the systemization done on an abstract level or for a specific product or branch?”; “Do the systematizations address the archetypical sustainability strategies?”; and “Do the systematizations consider any abstracted structure of SC or companies?”. The final step of the planning phase is the development of a review protocol (

Table 1. Review Protocol.

Research questions	How are sustainability measures systemized in the context of SC? Is the systemization done on an abstract level or for a specific product or sector? Do the systematizations consider any abstracted structure of SCs or companies? Do the systematizations address the three archetypical sustainability strategies?
Search terms	“Categorization of” AND (measures) OR “systematization of” AND (measures) AND “Supply Chain” AND “Sustainability”
Resources/Libraries:	Scopus, Google Scholar, SpringerLink
Study selection criteria	Inclusion: Any form of systematization of measures; published in English	Exclusion: Topics with no direct connection to corporate or SC sustainability (i.e., health, risk management, lean, operations research); published in other languages
Study selection procedures	Firstly, researcher A flags the relevant papers. Secondly, researcher B cross-checks the rejected papers for relevance.
Study quality assessment	Focusing on peer-reviewed publications
Data extraction strategy	Source, publishing year, authors, title, sector/focus, categories of measures
Synthesis of extracted data	Quantitative analysis, qualitative analysis, and deduction of a new systematization

).

After the planning phase, the SLR was conducted (see Figure 1). First, a pre-analysis of literature was conducted to refine the search terms and to obtain a basic idea of different systematizations of decarbonization measures. Google Scholar was used for this pre-analysis because it delivers more content and includes grey literature, resulting in a broader base for the SLR. The preliminary analysis led to 13 systematizations of sustainability measures that mainly refer to shipping or ports, which stresses the need for broader search terms.

The SLR (for overview: Table 1) starts with step 1 of identifying literature within the databases of Scopus, SpringerLink, and Google Scholar. Since the search terms “Categorization of” AND (measures) OR “systematization of” AND (measures) AND “Supply Chain” AND “Sustainability” occur in too many publications, the search of Google Scholar was narrowed down to reviews, and the search of SpringerLink was narrowed down to economics, environment, and technology, while the search on Scopus was not narrowed down.

In step 2, the relevant literature was flagged by one researcher after removing duplicates and performing a title abstract analysis. The inclusion criteria for the publications was that the title or abstract hinted any form of systematization of sustainability measures. Publications that were not related to the topics of SC sustainability or corporate sustainability were excluded. Only English-language publications were included.

A second researcher cross-checked the unflagged publications for relevance based on a title abstract analysis in step 3.

Step 4 involved retrieving and reading the relevant literature (13 publications from step 0, 42 publications from step 2, and 7 publications from step 3)—a total of 55 publications were retrieved and read.

Figure 2 shows that the number of publications per year is constantly growing. The year 2022 is not included in the figure because the number of publications will still grow, as the SLR was conducted early in the year 2022.

The publications come from a variety of different sources, mostly scientific journals, with some from project reports and some from conference papers (Figure 3). Most of the publications are from the journals Sustainability (Switzerland) with eight publications and Journal of Cleaner Production with five publications. Other journals included a single publication; examples are Circular Economy and Sustainability, Logistics, Energies, or The Asian Journal of Shipping and Logistics.

The analysis of the information and the found systematization forms the last step 5, which was done on a spreadsheet. This sheet includes a clear identifier and the bibliographic information of each publication (authors, title, year, journal). For every relevant publication, it was checked and marked if it included a form of categorization or systematization. If so, the categories were transferred to the spreadsheet, and the number of categories was listed for each publication. Furthermore, it was recorded whether the publication was focused on a certain sector or product (i.e., automotive, manufacturing, or shipping). The next question for the analysis was the inclusion of SC structures or company structures into the systematization (i.e., management, inbound logistics, or distribution). The final analysis questions for step 5 ask about the way sustainability is addressed by the systematizations. Do the publications address the triple bottom line (TBL)? Do the systematizations address the archetypical strategies: efficiency, consistency, and sufficiency? The results of the SLR are presented in the following section.

3. Results

The presentation of the results is divided into two parts. First, the results are presented in a quantitative level in the form of numbers, graphs, and tables and a qualitative description of the systematizations. In the second part, a new systematization is proposed based on the beforehand-presented results of the literature review.

3.1. Quantitative and Qualitative Results

The first result shows that the majority of the relevant publications include some form of systematization: 48 systematizations were found in 55 publications. These results show that many authors use a form of systematization for analysis and communication of their research about sustainability measures. A total of 286 different categories were extracted from the publications; the number of categories per publication varies between 1 and 17. The average number of categories per publication is 6—it is assumed that most authors consider this number as a good compromise between a too-specific and a too-abstract systematization. Thirty-one systematizations were found in publications that focus on a special sector, while the other seventeen publications include an abstracted systematization that can be applied to different sectors and SCs (Figure 4).

The analyzed systematizations vary a great deal, partly due to their sector focus, but even among the more general systematizations, a high variation was witnessed. The variety of different sectors is also an indication for the overall relevance of the topic: Sustainability measures are discussed in many sectors of the economy and different steps of the SC. Therefore, a systematization that can be applied in any sector has the potential to improve the scientific debate due to a similar wording and understanding for sustainability measures.

Table 2. Examples for specific or inconsistent systematizations.

Source, Sector and Systematization		Findings
[45] Logistics: Road transportation Air transportation Maritime transportation Rail transportation		Example for very specific systematization, which can only be applied in the logistics sector, exclusively for transportation processes. Many sustainability measures (i.e., concerning logistics processes such as storage or handling) cannot be integrated into these categories.
[46] Logistics Mode choice and intermodal transportation Logistics system design Transport management Vehicle technology	Behavioral aspects Alternative fuels Environmental management systems Choice of partners Emission data Efficient buildings	Example for a specific systematization, which allows for a high variety of measures to be integrated into the categories. Some of the categories are also applicable to other sectors (i.e., emission date, efficient buildings); others are just relevant for logistics operations.
[47] Chemistry Pollution control/prevention Environmental technologies Industrial biotechnology	Resource efficiency Eco-innovation/sustainable manufacturing Sustainable design Renewable chemicals	This systematization includes some general categories (i.e., eco-innovation, resource efficiency) and others that just work in the chemistry sector (renewable chemicals, pollution prevention).
[48] Product design Resource efficiency Low-impact materials Optimization end of life phase	Extend operational life Reduce emissions Multiple life cycles	This systematization has a very concrete focus on the life cycle of products (extend operational life, multiple life cycles), which makes it difficult to include other processes (logistics, management, etc.).
[49] Shipping Energy efficiency Low-carbon fuels Carbon pricing		In this example, the first two categories can be widely used not only for the shipping are but also for logistics or even manufacturing processes in general. The carbon pricing presents a category that is a concrete measure, which additionally can hardly be influenced by operators of the shipping or SC, respectively.
[50] Information systems SCM and increasing efficiency Teleshopping Virtual goods Intelligent transport systems Production process management		Another example for categories (teleshopping) that are too concrete to subsume other sustainability measures. Other categories are very general (SCM and increasing efficiency).

gives a number of examples where the systematization is difficult to generalize because of their sector focus [45,46,47,48] or their inconsistency [49,50]. Almost half of the found systematizations cannot be generalized (sector focus = 10 publications; inconsistencies = 12 publications).

Most of the systematizations (26 publications) present more abstract categories, which can be applied to many different fields. As the aim of this research is to develop a new abstract systematization, these publications are analyzed more in depth.

Generally, two different approaches were found:

• To focus on company divisions or SC sections (seven publications, including three inconsistent systematizations). Examples are:

  ⚬

  Inbound logistics, operations, outbound logistics, marketing and sales, service, procurement, and infrastructure [51];

  ⚬

  Warehousing, transportation, communication, packaging, and inventory management [52].

• Focusing on the TBL/sustainability dimensions (five publications):

  ⚬

  Environmental, social, and economic [53,54,55].

The examples of the first approach show that the categories can be very similar but still differ. None of the seven examples were identical.

The TBL (ecological, social, and economic perspective) was the only systematization that was identical in different publications. The publications were not only searched for a holistic consideration of all three dimensions but also for a consideration of each dimension. Environmentally focused categories were found most often, which might be partly due to a higher prioritization of ecology over the other dimensions (see for “Strong Sustainability”). However, one can also see that economic aspects and activities are automatically included in every company. Social aspects, especially with a perspective on intragenerational equity or intergenerational justice, are very difficult to measure, handle, or influence for companies or SC. These can be reasons for the prevalent integration of environmental categories.

Among the other 18 publications, no clear types could be differentiated. Together with all the other publications, they were searched for the consideration of the archetypical sustainability strategies. The consideration of archetypical sustainability strategies is one of the basic ideas of this paper, as it bears the potential to group measures regarding their functionality. While a mere word search for efficiency, consistency, and sufficiency just brought up few results (thirteen categories with the word efficiency and one category with the word sufficiency), a more detailed analysis found that in 27 of 48 systematizations, the identified categories could be assigned to at least one of the three archetypical strategies.

Table 3. Assignment of categories to archetypical strategies.

Archetypical Strategy	Exemplary Assignments of Categories
Efficiency	Reducing waste and energy, minimizing transportation, SCM and increasing efficiency, vehicle technology, material efficiency, vehicle fuel efficiency, extend operational life, design for maintenance, design for durability, maximize material productivity and energy efficiency, improve energy efficiency operational, engine internal measures
Consistency	Closing material loops, reusing and recycling products, virtual goods, alternative fuels, renewable chemicals, recovery, using emissions/outputs from processes as inputs, modal split, low-impact materials, design for cascades, circular economy, substitute non, renewable resources with renewable resources, changing type of energy source
Sufficiency	Behavioral aspects, regulation, dematerialization, green environment policy, deliver functionality instead of ownership of products, encourage sufficiency, rethinking the business model

exemplarily shows which type of categories was assigned to each strategy. This shows that the strategies are already a part of the majority of the systematizations without being explicitly used as categories.

In the Table 4, an overview of the analysis of the relevant sources and their systematization approaches is given based on the research questions stated in Section 2.2.

Table 4. Systematization approaches.

1st Author/Source	Product/Sector Focus	Departments/SC Sections Used	Level Abstraction	Sustainability Consideration
Lovrenčić [9]	Yes		Abstract
Shah [11]		Yes		Efficiency, consistency, sufficiency
Siddh [14]	Yes		Abstract	TBL
Nguyen [24]	Yes		Inconsistent	Efficiency, consistency
Alamoush [25]	Yes		Inconsistent	Efficiency
Alamoush [26]	Yes		Concrete	Consistency
Corlu [45]	Yes		Concrete
Martinsen [46]	Yes		Concrete	Efficiency, consistency, sufficiency
Díaz López [47]	Yes		Concrete	Efficiency, consistency
Mesa [48]			Concrete	Efficiency, consistency
Int.Transp. [49]	Yes		Inconsistent	Efficiency, consistency
Piotrowicz [50]	Yes	Yes	Inconsistent	Efficiency, consistency
Müller [51]		Yes	Abstract	TBL
Surucu-Balci [52]	Yes	Yes
Azevedo [53]			Abstract	TBL
Hristov [54]			Abstract	TBL
Feil [55]			Abstract	TBL
Vimal [56]	Yes		Abstract	Efficiency
Kozlowski [57]	Yes		Abstract
Manning [58]	Yes		Inconsistent	Efficiency, consistency
Li [59]	Yes		Concrete	Efficiency, consistency
Rietbergen [60]	Yes		Abstract	Efficiency, consistency
Panagakos [61]	Yes		Concrete	Efficiency
Zhao [62]	Yes		Abstract
Damert [63]	Yes		Abstract
Schnabel [64]	Yes	Yes		Efficiency, consistency
Olatunji [65]	Yes	Yes	Inconsistent	Sufficiency
Eslami [66]	Yes		Abstract
Vimal [67]	Yes		Concrete
Serra [68]	Yes		Abstract
Psaraftis [69]	Yes		Inconsistent	Sufficiency
Neri [70]	Yes		Abstract
Frare [71]	Yes		Abstract
Abubakari [72]	Yes		Abstract	Efficiency, consistency, sufficiency
Negri [73]	Yes
Song [74]	Yes		Abstract	Consistency
Liu [75]		Yes	Abstract
Lee [76]			Abstract	Efficiency, consistency
Jawahar [77]			Abstract
Gholami [78]			Abstract
Schäfer [79]			Abstract
Sinkovics [80]			Abstract
Muchangos [81]			Abstract	Efficiency, consistency, sufficiency
Krajnc [82]			Concrete	Efficiency, consistency
Willskytt [83]			Concrete	Efficiency, consistency, sufficiency
Dawal [84]			Inconsistent	Efficiency, consistency, sufficiency
Balcombe [85]			Inconsistent	Efficiency, consistency, sufficiency
Mejia [86]			Inconsistent
Mello Santos [87]			Inconsistent	Efficiency, consistency

Table 4. Systematization approaches.

1st Author/Source	Product/Sector Focus	Departments/SC Sections Used	Level Abstraction	Sustainability Consideration
Lovrenčić [9]	Yes		Abstract
Shah [11]		Yes		Efficiency, consistency, sufficiency
Siddh [14]	Yes		Abstract	TBL
Nguyen [24]	Yes		Inconsistent	Efficiency, consistency
Alamoush [25]	Yes		Inconsistent	Efficiency
Alamoush [26]	Yes		Concrete	Consistency
Corlu [45]	Yes		Concrete
Martinsen [46]	Yes		Concrete	Efficiency, consistency, sufficiency
Díaz López [47]	Yes		Concrete	Efficiency, consistency
Mesa [48]			Concrete	Efficiency, consistency
Int.Transp. [49]	Yes		Inconsistent	Efficiency, consistency
Piotrowicz [50]	Yes	Yes	Inconsistent	Efficiency, consistency
Müller [51]		Yes	Abstract	TBL
Surucu-Balci [52]	Yes	Yes
Azevedo [53]			Abstract	TBL
Hristov [54]			Abstract	TBL
Feil [55]			Abstract	TBL
Vimal [56]	Yes		Abstract	Efficiency
Kozlowski [57]	Yes		Abstract
Manning [58]	Yes		Inconsistent	Efficiency, consistency
Li [59]	Yes		Concrete	Efficiency, consistency
Rietbergen [60]	Yes		Abstract	Efficiency, consistency
Panagakos [61]	Yes		Concrete	Efficiency
Zhao [62]	Yes		Abstract
Damert [63]	Yes		Abstract
Schnabel [64]	Yes	Yes		Efficiency, consistency
Olatunji [65]	Yes	Yes	Inconsistent	Sufficiency
Eslami [66]	Yes		Abstract
Vimal [67]	Yes		Concrete
Serra [68]	Yes		Abstract
Psaraftis [69]	Yes		Inconsistent	Sufficiency
Neri [70]	Yes		Abstract
Frare [71]	Yes		Abstract
Abubakari [72]	Yes		Abstract	Efficiency, consistency, sufficiency
Negri [73]	Yes
Song [74]	Yes		Abstract	Consistency
Liu [75]		Yes	Abstract
Lee [76]			Abstract	Efficiency, consistency
Jawahar [77]			Abstract
Gholami [78]			Abstract
Schäfer [79]			Abstract
Sinkovics [80]			Abstract
Muchangos [81]			Abstract	Efficiency, consistency, sufficiency
Krajnc [82]			Concrete	Efficiency, consistency
Willskytt [83]			Concrete	Efficiency, consistency, sufficiency
Dawal [84]			Inconsistent	Efficiency, consistency, sufficiency
Balcombe [85]			Inconsistent	Efficiency, consistency, sufficiency
Mejia [86]			Inconsistent
Mello Santos [87]			Inconsistent	Efficiency, consistency

3.2. Deduction of a New Systematization

The results shown in Section 3.1 lead to the proposal of a new systematization for sustainability measures. As this systematization is supposed to be generally applicable, it should not include any sector specific categories (Table 2). The two approaches found that systemize on an abstract level include either a consideration of sustainability (TBL) or sections of the SC/company divisions. The idea is to combine these two approaches in a matrix with two axes. One of them refers to the effect mechanism, and the other refers to the effect location. While the effect location refers to the section of the company or SC where the measure can be applied, the effect mechanism can be described by the archetypical sustainability strategies.

A general way to structure companies or SC is to differentiate between the product, process, and system level. This approach was found in [78] to structure sustainable manufacturing. The product is also referred to as the object and includes physical goods and information. The process level refers to operations including material and information flows. The system level refers to transport and management systems as well as storage and conveying systems [88]. Objects, processes, and systems can be found in every company or SC and therefore be seen as generally applicable categories.

As described in Section 2.1, sustainability can be reached by sufficiency, consistency, or efficiency measures. Therefore, any sustainability measures can be subordinated to one of these strategies. As one aim of this research is to support decision makers in the selection of measures for sustainability transformation, a prioritization of the strategies is needed.

Sufficiency measures are about behavioral change and reducing the need or at least the needed number of products or processes. Consistency measures are generally aimed at making, designing, or planning products, processes, or systems in a not harmful or damaging way. Finally, the efficiency measures propose the option of iterative relative improvements of the ratio of efforts (energy/material/etc.) and benefits of products, processes, and systems. This paper proposes a hierarchical order of these strategies based on reasoning and literature: The option to omit certain products/processes or systems by a sufficiency measure should always be checked first, as it tackles the problem at the root. Reducing the need has a potentially direct and immediate effect, as no capacity (human or material) is necessary. This can be supported by the ECRS (eliminate, combine, replace, and simplify) method from lean manufacturing, which always starts with eliminating unnecessary processes [89]. The second-best option is the one of the consistency measures. As they are about doing things differently and not harmfully, they bear a high potential. Even with circular processes and renewable materials or energies, they still consume some natural capacity. Therefore, their potential is not as high as sufficiency measures, which potentially reduce the need for natural capacity completely. The efficiency measures are only the third option, as their improvement is just relative to the level before. The harmfulness can be lowered but not eliminated. This is a general attribute of this kind of measure, which is connected to their basic mechanism. As their effect is often inhibited or reduced by so-called rebound effects [40], the focus on these measures by many publications should be questioned critically. The proposed systematization of sustainability measures is presented in

Table 5. Proposed method to categorize sustainability measures in SCs.

	Level	Product	Process	System
Strategy
Sufficiency
Consistency
Efficiency

. While the columns “Product” and “Process” represent measures that can be implemented in the short term, measures referring to the “System” level need to be addressed from a strategic and long-term perspective.

In the next section, the proposed method is exemplarily applied to an example SC in the food sector. On one hand, the table can be used for a complete decarbonization of a SC, starting with sufficiency measures and continuing with consistency and efficiency measures on different levels (Figure 5, on the left). On the other hand, it can also be used to prioritize measures on a certain level or for different roles in the SC; i.e., a logistics planner is often responsible for the process level, a designer works on the product level, and managers are responsible for the system level (Figure 5, on the right). In both applications of the method, it is possible to skip a certain a column or a row, as not always all types of measures are available. In this paper, the holistic decarbonization of a SC is exemplarily described, as this gives examples for every possible assignment in the table.

4. Exemplary Application

The example chosen for the application is the theoretical case of apples produced in New Zealand and sold in a German supermarket. After production, the apples are packed into crates and placed onto pallets, which are loaded into refrigerated containers and then transported by truck from the plantations to a New Zealand port. They are then shipped to a European port (e.g., Rotterdam), where they are loaded onto a truck that transports them to a central warehouse. The pallets are stored in the warehouse, which is usually equipped with a controlled-atmosphere technology. The last step of SC is a fine distribution to supermarkets. The apple crates are loaded onto dollies and then transported to the supermarket by truck.

The first step is to see if sufficiency measures can be applied at the product level. Is the product completely necessary, or can it be reduced in some way? One possible measure is to adjust the supermarket assortment. Imported fruits could be removed from the assortment, reducing their share of the assortment or replacing them with apples produced with less energy (e.g., by using fewer fossil fertilizers). The second step is to review sufficiency measures at the process level. Are all processes necessary, or is there a way to omit some? Measures would be to omit refrigeration, packaging, or storage processes. Another way would be to allow lower inventory levels in the supermarket in exchange for higher utilization of transport means. The third step is to look for sufficiency potential at the system level. Are all production or logistics systems necessary, or can they be reduced? Possible measures include reducing storage capacity or the number of machines (e.g., cleaning and packaging machines, trucks). The next step is to continue with consistency measures in the second line of Table 5. Again, starting from the product level, the question regards how the circular economy can be applied. Since apples and natural products are already made from renewable materials, the question is: Is the packaging ready for the circular economy? Are the by-products (unsold apples, discarded packaging, etc.) reused or recycled? Consistent actions include using waste products, switching to reusable packaging, and using renewable and recyclable materials. The next level is about processes that are planned and operated with the circular economy in mind. Are processes powered by renewable energy? Are reused or recycled materials integrated into the processes? Example measures include electrifying processes and supplying renewable energy instead of fossil fuels. All material use can be switched to circular products, i.e., reusing loading equipment or other products instead of disposable products. The final step in consistency measures is to review system-level measures. Are production and logistic systems designed and operated according to circular economy principles? Are buildings, production facilities, and warehouses constructed from renewable or recycled materials? Are renewable energy systems integrated at all SC sites? Do the operating principles prioritize environmental benefits over economic benefits or at least internalize environmental costs? An example would be transporting apples in recycled plastic, reusable shipping crates even if the alternative of traditional plastic or disposable boxes is cheaper. The next row of Table 5 is about considering efficiency measures. Can the product, the processes, or even the system become more energy- or material-efficient? The measures start at the product level with energy savings in the production of apples. Is there potential for efficiency in the machinery used for production? Can the packaging be changed to optimize its material consumption? The product type can also be changed, as some apple varieties have a higher density and require more energy for transport or cooling. Possible process-level measures include making transportation and storage more efficient by using more efficient engines or means of transportation, operating them more efficiently (e.g., driving container ships slower), or using them more intensively. Efficiency measures can also be implemented at the system level. The entire logistics network can be designed to operate more efficiently. Consolidating transports is an option, as it is realizing energy efficiency potential in buildings. All exemplary measures are summarized in

Table 6. Exemplary assignment of decarbonization measures.

	Level	Product	Process	System
Strategy
Sufficiency		Excluding imported apples from assortment Reducing share of imported apples Replacing product with lower-energy products	Omit processes (i.e., cooling, packaging, storing) Change stock-related order points	Reduce number of/capacities of logistic and productions systems
Consistency		Using renewable and recyclable materials Reusable packaging or loading aides Using waste/outputs for other purposes	Electrify processes using renewable energies Changing material inputs towards circular products	Green buildings and production sites Integrating renewable energy plants Ecological operating principles
Efficiency		Energy-efficient production Optimized packaging Lighter products	Using energy-efficient transport means Operating machines efficiently Increasing usage	Energy-efficient factories and buildings Efficient network design/consolidation

. This exemplary application shows that measures can be found for each cell in the table and that the measures can be clearly distinguished from each other in terms of their mode of action and level of application. In the next sections of this paper, the proposed system is discussed in terms of its validation, benefits, and implications and further research directions.

5. Discussion

The SLR results show that there are many different ways to categorize sustainability measures. As shown in Section 3.1, there are many systematization approaches that work only for a specific sector, for example, sustainability measures in shipping [24], automotive [63], or somewhat more generally in manufacturing [67]. The proposed systematization has the ambition of a general validity for all sectors and types of supply chains. Widespread applicability of the approach may help it to become recognized as a kind of standard.

Another aspect is the number of categories per systematization approach. If the categories are very broad (i.e., a small number of categories), they describe the measures poorly. Examples are systematization by TBL [53,54,55] or by effect level (i.e., facility design and operations, production planning and control, supply chain network design [66]; supply, demand, product, information [70]). If the categories are very narrow (i.e., a high number of categories), the classification of the measures becomes very complex, which makes the systematization less suitable to support their analysis and discussion. Examples are approaches with 16 or 17 categories [11,83]. The developed systematization is based on two axes, each subdivided into three sections. The resulting matrix offers nine possibilities to classify measures, which places this approach somewhere in the middle of all systematizations examined.

The developed approach to systematization must be compared above all with other generally applicable approaches. Section 3.1 elaborates on two ways of this abstract systematization: with reference to the SC sections or with reference to the TBL. Since business processes and SC can be very complex, there are numerous ways to divide them into different sections. None of the seven publications that distinguish measures in this way take the same approach. Some refer to different phases of the product life cycle (design, planning, purchasing, processes, distribution, communication, and reverse logistics [11]), and others group enterprise functions (technical, behavioral, and organizational practices [75]). The proposed approach divides by objects, processes, and systems, as in [78], and can be applied equally in service, logistics, or manufacturing companies, among others.

Finally, the developed approach is compared with the systematization according to the TBL. For the differentiation of sustainability measures, the focus will be on the basic functionality, which is given by the three archetypical sustainability strategies. This makes more sense than the use of the TBL [14,51,53,54,55]. The TBL refers to very general fields of action (namely ecological, social, and economic aspects) without any reference to the impact mechanism (described by efficiency, sufficiency, and consistency) of the respective measures. On one hand, the separation of the sustainability dimensions leads to the fact that each field of action stands for itself. Sustainability is a holistic approach that aims at a joint consideration of the three dimensions. The proposed approach does not make this division and is seen as a holistic approach. On the other hand, the sustainability strategies can be used to justify a prioritization of measures; thus, the proposed systematization can also be used as a decision-support system.

6. Conclusions and Further Research

The multitude of global crises makes it a central task to select and prioritize measures for sustainability. In particular, for the international network of SC, full decarbonization is essential, as this is seen as a prerequisite for future value creation. The example of fresh SC supplying European countries with fruits such as apples shows how much the daily supermarket assortment depends on fossil fuels: Long transport distances and energy-intensive storage are far from being decarbonized. Many research activities are dedicated to support the transformation of fresh SC by analyzing its carbon footprint, studying food waste, applying optimization methods, or discussing concepts such as regionality or GSCM. While most publications discuss different sustainability measures, there is no standardized system to classify these measures. The systematic literature review conducted supports this fact and shows the wide range and diversity of approaches to systemize sustainability measures. Based on the SLR, a new system of classifying sustainability measures is developed, which directly allows prioritizing measures according to their fundamental mode of action. While efficiency measures only have an iterative and relative improvement potential, sufficiency and consistency measures can have an effect independent of their previous emission levels. The introduction of the impact levels (the product, process, and system levels) in the newly developed systematization results in a general applicability, which contrasts with many previous sector-specific approaches.

The practical applicability of the new system is demonstrated using the example of imported apples from New Zealand.

The present work is intended as a starting point for further research. The systematization was successfully applied to an exemplary SC in the food sector. Measures for further SC in the food sector and also in other sectors should be classified with this systematization. In the food sector, these could be shorter/regional SCs on one hand and more complex SC on the other hand, which include processing steps of the products. Clearly, more interconnected and multi-stage SC, such as those in the electronics sector, mechanical engineering, or the automotive industry, are also recommended for further studies.

In the future, the systematization will serve as the basis for a study quantifying the potential of sustainability measures for decarbonization. The sustainability effect, i.e., the savings effect, is to be measured with the help of simulated SC models. Further research will measure and compare the effectiveness of the different classifications of sustainability measures, which may support or overturn the qualitative justification of prioritizing sustainability strategies of this work with quantitative results. Future analysis of sustainability measures using the preceding approach will reveal whether all measures can be classified in the matrix or whether additional categories are needed. Additions are conceivable for both axes; the impact levels could be supplemented even more macroscopically by infrastructure, and the impact mechanism could be supplemented by resilience and compensation measures. For the latter, it should be discussed to what extent these measures are considered sustainability measures since they do not proactively limit damage but have a reactive effect. Last, since the systematization is intended to function as a decision-support tool, research on its practical usefulness for managers or other decision makers in SC is of interest. The presented systematization is a new approach with a broader application (all kind of sectors) and is a more in-depth consideration of sustainability (three archetypical strategies).