Palm Oil Sustainability: Current and Further Potential Research to Adopt Sustainable Development Goals 2030

The issue of sustainability in the palm oil industry is frequently discussed due to its significant impacts and benefits for society. This research aims to examine the current state of palm oil sustainability research and suggest potential areas for future research. A systematic literature review approach is used to select relevant articles on the sustainability of palm oil production. The study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) framework to identify relevant articles, which are then analysed using both qualitative and quantitative methods. VOSViewer is employed to analyse the bibliographic data of these articles, helping identify potential future research directions based on author keywords. This study has successfully categorized 532 articles from the Scopus database that directly relate to the sustainability of the palm oil industry. The results of the qualitative and quantitative analyses indicate that in recent years, based on their keywords, research trends are moving towards circular economy, biodiversity, tropical agriculture, policy, and palm oil clinker. Judging from the majority of cited articles, future research trends are recommended to focus on productivity aspects, the development of palm oil derivative products, and supply chain performance for the sustainability of the palm oil industry.


Introduction
Sustainability is a critical issue that needs to be addressed across industries to harness the benefits of current resources without compromising the well-being of future generations.Industries play various roles in preserving sustainability, even in the era of Industry 4.0 aimed at modernizing industrial processes while ensuring sustainability [1].Industries are no longer seen as threats but have become means to achieve sustainability.However, it's essential that all industrial sectors align with the vision of sustainability.
The vision for sustainability was jointly formulated by the United Nations in 2015, under the name Sustainable Development Goals (SDGs).Earlier, a similar vision had been communicated through the Millennium Development Goals, which included eight key objectives [2].Sustainability has been widely accepted by the international community as a strategy to ensure a more stable environment, society, and economy in the present and future.
The Sustainable Development Goals (SDGs), as a guiding framework for sustainability, consist of 17 primary goals.One of the goals related to industrialization is the ninth goal, which pertains to "industry, innovation, and infrastructure," and the twelfth goal, focusing on "responsible consumption and production."The palm oil industry plays a crucial role in both of these goals and is directly associated with industrialization and production.The palm oil industry, primarily originating from developing countries, demonstrates production efficiency and continuous downstream processes but IOP Publishing doi:10.1088/1755-1315/1324/1/012077 2 faces challenges in upstream processing.Palm oil is highly sought after globally due to its high productivity and versatile applications.It can be transformed into various derivative products, broadly categorized into food, non-food, and energy products [3].
Several previous studies have highlighted sustainability-related issues closely associated with the palm oil industry, including deforestation and biodiversity impacts [4,5], greenhouse gas emissions resulting from production and cultivation [6,7], the trade-off between food and energy production [8], among others.However, palm oil also offers various benefits for industrial development, farmers, and societal well-being.The palm oil industry involves multiple stakeholders, actors, and sectors, making its challenges more complex.It is crucial to prioritize discussions on the sustainability of the palm oil industry to guarantee that it brings advantages in the current period, doesn't pose threats to the future, and is in harmony with the principles of the SDGs.
The sustainability of palm oil has been studied by various researchers even before the SDGs were adopted by the UN.Basiron et al. [9] discussed sustainable palm oil production processes, Shuit et al. [10] explored bioenergy as a sustainable derivative of palm oil, and Wolf [11] formulated the role of supply chain management impact on the sustainability performance of the industry.These diverse sustainability investigations have been carried out from various angles, underscoring the importance of assessing the present status of research concerning palm oil sustainability and plans for its future development.In this regard, a systematic literature review approach is necessary to obtain comprehensive information about the sustainability of the global palm oil industry.
The objective of this study is to perform a systematic literature review on palm oil sustainability and to suggest further research potential.This paper adopts a well-structured approach with comprehensive data to provide insights and recommendations.This literature review combines qualitative and quantitative methods to ensure that findings and recommendations are in line with data availability and offer more accurate guidance.

Reserach framework and stage
This study is undertaken to examine the current state of research on the global palm oil industry and to anticipate potential developments in the future.A review approach, focusing on reputable international articles, is employed to analyze the current situation and recommend areas for future research and development.
In the initial stage, ideas and problem formulations are put forward.The main issue addressed in this research is the sustainability problem in the palm oil industry, aligning with the issues and goals of SDG 2030.A review approach is employed to examine the development of research in previous years and to analyze the current state of global palm oil sustainability.To ensure comprehensive knowledge, credible sources are essential.In this regard, the Scopus database is utilized to compile all articles pertaining to the sustainability of palm oil.
This study employs a systematic literature review approach with a combination of qualitative and quantitative analysis.This dual approach is highly effective in generating recommendations as it involves in-depth synthesis supported by secondary data.Two approaches and methods are utilized in the combination of qualitative and quantitative analyses: a systematic literature review approach using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), bibliography analysis with VOSViewer, and article citation network analysis using Connected Papers tools.

Data acquisition
There are two types of data required for this study: article data obtained from Scopus.com and supporting data related to the global palm oil industry collected from various sources.The articles for this research were retrieved from Scopus.com using the following keywords: TITLE-ABS-KEY (palm AND oil AND sustainability) AND (LIMIT-TO (EXACTKEYWORD,"Palm Oil") OR LIMIT-TO (EXACTKEYWORD, "Sustainability") OR LIMIT-TO (EXACTKEYWORD,"Sustainable Development")) AND (LIMIT-TO (DOCTYPE,"ar") OR LIMIT-TO (DOCTYPE,"cp")) AND (LIMIT-TO (LANGUAGE, "English")) The articles obtained through these keywords are then analyzed and assessed for their relevance to the research context.The articles also undergo a filtration process in accordance with the PRISMA framework.The articles obtained from the Scopus database are not merely used as general information but are subjected to in-depth analysis through bibliographic examination and substantive reviews to identify potential research developments in the future.
Additionally, to support the analysis, secondary data required for this research is obtained from statistical agencies or palm oil sustainability institutions such as the Roundtable on Sustainable Palm Oil (RSPO).

PRISMA and VOSViewer framework for data analysis
The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was originally introduced by [12] as a systematic and structured methodology for conducting reviews.PRISMA has been applied in numerous review studies, as evident in research by Papilo et al.
[3] on bio-energy policy, Sahoo et al. [13] on the Industry 4.0 framework, Ismail et al. [14] on palm oil consumption and its risks, and other scholarly works.PRISMA offers a step-by-step approach to review papers while ensuring the inclusion of the most relevant article sources related to the research subject.Utilizing PRISMA enables a more structured analysis of articles and helps identify those that are not relevant to the discussion.
In this study, the article sources utilized are sourced from the Scopus database, with careful consideration of their relevance to palm oil sustainability.The final selection of articles through PRISMA's filtering process is then subjected to both quantitative and qualitative analysis.The quantitative analysis primarily focuses on bibliographic analysis using VOSViewer.VOSViewer, initially proposed by [15], serves as a comprehensive tool for analyzing keywords, authors, and other bibliographic data that can support the analysis and aid in identifying further research potential.
In this analysis, VOSViewer is employed to conduct an author keyword analysis using the full counting method to analyze current research maps and determine future research directions.This quantitative analysis is further complemented by a qualitative examination of articles with the highest citations.These articles are scrutinized to observe the development of research in their derivative works and to map articles citation.

Review process and data visualization
The articles reviewed in this study were obtained from the Scopus database using the keywords mentioned earlier.There were a total of 913 articles associated with the modeled keywords.However, it was necessary to conduct a rapid screening and review of all these articles.Therefore, in this regard, the PRISMA framework was employed to ensure that the study's objectives were met.The PRISMA model implemented in this study can be observed in Figure 1.To obtain an accurate result in line with the subject under study, several stages have been carried out.In the first stage, the elimination of duplicate articles was performed, where 3 articles were removed.There were 910 articles that proceeded to the next stage.Subsequently, these articles were subjected to analysis to eliminate irrelevant articles.
To identify the most relevant articles, two keywords were used in the article filtration process, namely "palm oil" and "sustainability."Article selection and screening were performed sequentially, resulting in 327 articles with the keyword "palm oil" and 379 articles with the keyword "sustainability."To prevent data duplication, duplicate articles were subsequently removed.In the end, there were 532 articles that were further used for sustainability analysis related to palm oil.
In general, there has been a global discussion on the quantity of publications concerning the sustainability of palm oil.All nations have shown a shared concern for sustainability issues, motivated by their aspirations for a safer future.The distribution of publications by country is depicted in Figure 1324   The number of publications related to palm oil sustainability has also seen a rapid increase since 1996 in the Scopus database.It is noteworthy that the highest number of publications occurred in 2021, totaling 121 publications.This increase in publications is also significantly associated with the launch of the Sustainable Development Goals (SDG) in 2015 and the establishment of the Roundtable on Sustainable Palm Oil (RSPO) in 2004.The distribution of publications by year can be observed in Figure 3.

Southeast Asia as palm oil epicentrum
The highest number of publications related to palm oil and sustainability is primarily found in Southeast Asian countries, particularly Malaysia and Indonesia.One of the main drivers behind this is that Southeast Asian nations are the world's leading producers of palm oil, with Indonesia (59%) and Malaysia (24%) being the major contributors (US Department of Agriculture).
Palm oil-producing nations are also confronted with various production-related issues, both upstream and downstream in the industry.Another recurring concern is the sustainability of palm oil production from its source to its various applications.In fact, issues related to palm oil sustainability in Indonesia and Malaysia are often influenced by political and business strategies [16].Industries in both countries have been associated with activities that have led to sustainability challenges, such as deforestation, labor practices, and environmentally friendly production methods.
In line with the vision of palm oil sustainability, Indonesia, Malaysia, and other palm oilproducing nations in Southeast Asia have been following recommendations for sustainable palm oil certification.If we examine the data, a majority of mills and concessions in Indonesia and Malaysia have been certified to accommodate the adoption of sustainable palm oil practices.The certified RSPO status of palm oil businesses in Indonesia and Malaysia can be observed in Figure 4. Source: rspo.orgCertification through accredited bodies is not the sole solution to ensure that palm oil can be sustainable.There are several aspects that need to be considered in palm oil certification that have not been included in the sustainability dimensions or indicators.Gatti et al. 2019 [17] mentioned that palm oil certification cannot guarantee the prevention of deforestation and biodiversity threats.Furthermore, palm oil certification, aside from providing benefits, can also have social impacts [18].

Bibliographic analysis using VOSViewer
The bibliographic analysis using VOSViewer is depicted in Figure 5. Quantitatively, articles directly related to palm oil sustainability were analyzed using VOSViewer.VOSViewer is an attractive software developed by [15] that aids in article analysis through keyword occurrences within the articles.VOSViewer provide two analysis the association of each articles: full and fractional counting.In this analysis, the study established rules for analyzing occurrence keywords originating from authors using the full counting technique.Full counting provided all articles association to produce comprehensive conclusion.VOSViewer suggests frequently appearing keywords, which were then eliminated based on their relevance to this research.Additionally, to enhance the analysis, a normalization method was employed, taking into account the association method and combining clusters with fewer than 5 keywords.

Figure 5. VOSViewer rule of analysis
A well-organized process for analyzing and visualizing keywords from 532 Scopus articles using VOSViewer can be observed in Figure 6.The clustering of keywords in articles related to palm oil sustainability led to the identification of five distinct clusters, which are: Cluster 1 -Palm oil certification on sustainability Agriculture, certification, deforestation, governance, human rights, ISPO, legitimacy, palm oil, remote sensing, RSPO, smallholders, supply chain, sustainability standards.

Cluster 2 -sustainability development on palm oil business process
Biodiesel, biofuel, biorefinery, circular economy, land use change, microalgae, oil palm biomass, palm oil industry, mill effluent, policy, sustainable development, sustainable palm oil.Cluster 3 -palm oil environmental impact Biodiversity, bioenergy, biofuels, biomass, climate change, environmental impact and sustainability, life cycle assessment, oil palm, plantation management, renewable energy, tropical agriculture.
Cluster 4 -Sustainability assessment on palm oil industry Assessment, environmental, life cycle assessment, palm oil mill and production, social, sustainability assessment, sustainable.
Cluster 5 -Palm oil industry by product Comprehensive change, mechanical properties, palm oil clinker, palm oil fuel ash, response surface method, self-compacting concrete, sustainability.
The analysis of keywords related to palm oil sustainability literature has resulted in five clusters based on their associations.The relationships between keywords extracted from articles through the keyword-by-author method have been depicted in Figure 7.The connections between keywords indicate associative relationships and their relevance in terms of their occurrence in the 532 articles submitted for inclusion in the scope of palm oil sustainability.Referring to Figure 8, from 2019 to the present, research has focused on topics such as biodiversity, tropical agriculture, policy, palm oil clinker, circular economy, and microalgae.It can be observed that these keywords are part of the clusters of "palm oil by product" and "palm oil sustainability assessment."These topics are potentially developed in the future for further contribution in academics and practitioners for palm oil sustainability.

Citation and article content analysis
A total of 532 articles have been quantitatively analyzed using the PRISMA and VOSviewer approaches.In the following section, we will analyze the development of research related to palm oil sustainability, particularly in articles with high citations.Based on the analysis results, the citation counts for all articles showed in Figure 8.
The Pareto diagram shows that there are 450 articles from the scope of palm oil sustainability that have been cited and further developed into derivative studies.Among all the cited articles, 20% of the articles have the highest citations, as shown in Table 1.These highly cited articles make significant contributions and have had a substantial impact on the advancement of knowledge up to the present and possibly in the future as well.There are three articles with the highest citations in the aspect of palm oil sustainability obtained from the Scopus.comdatabase.These highly cited articles were then decomposed to examine their derivative articles and associations in further research, using the tools provided by connectedpapers.com.The three articles analyzed through Connected Papers are Basiron [9], Shuit et al. [10] and Wolf [11].These three articles have different themes and keywords in accordance with the evolving knowledge in the field of palm oil sustainability.They also play a significant role in the development of knowledge and discussions related to palm oil sustainability.

Conclusion
Research on palm oil sustainability has been addressed in previous studies.The expansion of this field of research is driven by multiple factors, including the adoption of SDGs since 2030, the diverse applications of palm oil as a commodity, the certification and sustainability aspects of palm oil and its by-products, and concerns related to deforestation, greenhouse gas emissions, and the well-being of small-scale farmers.This research has systematically analyzed articles related to palm oil sustainability using both qualitative and quantitative approaches.A total of 532 articles have been reviewed, and key keywords from previous research have been synthesized.In the future, research potential, based on keywords, will revolve around biodiversity, palm oil sustainability assessment and palm oil by product processing.Besides examining keywords, the exploration of palm oil sustainability can also be approached by considering the most highly cited articles.Three distinct categories of articles with varying subjects garner the highest number of citations, constituting 20% of the overall citations among all articles in the domain of palm oil sustainability.Referring to these articles, there are three potential research scopes on palm oil sustainability that will continue to be discussed in the future: palm oil production and cultivation, palm oil biomass, bioenergy, and downstream products, and sustainable supply chain management in palm oil production.
Considering the adoption of SDGs 2030, practitioners and academician are potentially to continue the palm oil sustainability research contribution to the sustainability goal achievement.For further research, it is essential to adopt SDGs indicator to evaluate the palm oil sustainability contribution and maps its impact in goal achievements.

References
(2024) 012077 IOP Publishing doi:10.1088/1755-1315/1324/1/0120774 2. It can be observed that the quantity of publications related to palm oil worldwide is predominantly led by countries in Southeast Asia.Malaysia and Indonesia take the lead in the number of such publications, with 347 and 193 publications related to palm oil sustainability, respectively.

Figure 4 .
Indonesia and Malaysia palm oil mills and concession certified by RSPO

Figure 8 .
Figure 8. Number of citation by article [1] Müller J M, Kiel D and Voigt K-I 2018 What Drives the Implementation of Industry 4.0?The Role of Opportunities and Challenges in the Context of Sustainability Sustainability 10 247 [2] Brown N J and Beattie R M 2015 The millennium development goals: Taking stock as the first phase ends vol 100 [3] Papilo P, Marimin M, Hambali E, Machfud M, Yani M, Asrol M, Evanila E, Prasetya H and Mahmud J 2022 Palm oil-based bioenergy sustainability and policy in Indonesia and Malaysia: A systematic review and future agendas Heliyon 8 e10919 [4] Cisneros E, Kis-Katos K and Nuryartono N 2021 Palm oil and the politics of deforestation in Indonesia J. Environ.Econ.Manage.108 102453 [5] Vijay V, Pimm S L, Jenkins C N and Smith S J 2016 The Impacts of Oil Palm on Recent Deforestation and Biodiversity Loss PLoS One 11 e0159668 [6] Lam W Y, Kulak M, Sim S, King H, Huijbregts M A J and Chaplin-Kramer R 2019 Greenhouse gas footprints of palm oil production in Indonesia over space and time Sci.Total Environ.688 827-37 [7] Meijide A, de la Rua C, Guillaume T, Röll A, Hassler E, Stiegler C, Tjoa A, June T, Corre M D, Veldkamp E and Knohl A 2020 Measured greenhouse gas budgets challenge emission savings

Table 1 .
The articles with the highest citations on the theme of palm oil sustainability