Too Much of a Good Thing? Navigating the Abundance of E&S Metrics in Ports’ Sustainability

Abstract

As global sustainability goals gain momentum, seaports are playing a pivotal role in driving environmentally and socially responsible practices. In light of the International Maritime Organization’s emission reduction targets, transparent and effective Environmental and Social (E&S) reporting has become increasingly vital. This study critically examines current E&S reporting practices in the port industry through an analysis of recent disclosures from major European and global ports, supported by a review of academic and industry literature. The research explores how sustainability reports address key themes such as CO₂ emissions, energy efficiency, health and safety, operational performance, and biodiversity. While the presence of numerous indicators reflects a commitment to comprehensive sustainability, the proliferation of metrics poses challenges for clarity, comparability, and stakeholder engagement. The abundance of data risks diluting focus, complicating benchmarking, and may even contribute to greenwashing. Without standardization and strategic alignment, reporting can become counterproductive. This study advocates for a harmonized set of performance indicators that remain flexible enough to reflect port-specific strategies, yet are consistent with global benchmarks. Achieving this balance will require collaboration among researchers, industry leaders, and policymakers to develop transparent, adaptive E&S reporting frameworks that support meaningful progress in ports’ sustainability.

1. Introduction

As the global community grapples with escalating sustainability challenges, seaports find themselves at a pivotal crossroads. The European Union’s commitment to achieving carbon neutrality by 2050 [1] and the International Maritime Organization’s (IMO) decisive targets to reduce greenhouse gas emissions [2] are not distant ambitions—they are urgent imperatives that call for immediate, coordinated, and strategic action. As critical gateways in global trade, ports play a central role in meeting these targets and must therefore implement comprehensive sustainability strategies, supported by robust performance indicators (PIs) to monitor, evaluate, and transparently communicate their progress.

In response to growing environmental and social (E&S) concerns, regulatory frameworks are tightening. The European Directive on Corporate Sustainability Reporting [3] sets a new benchmark for corporate transparency and accountability, compelling organizations—including ports—to systematically disclose their sustainability performance to stakeholders and the public. This legislative push aims not only to drive environmental and social responsibility but also to strengthen sustainable business practices across sectors.

At the same time, stock exchanges worldwide are increasingly requiring listed companies to disclose sustainability PIs [4], leading to a sharp rise in voluntary corporate reporting. The 2007 UNEP Finance Initiative report “Demystifying Responsible Investment Performance” [5] concludes that incorporating environmental, social, and governance (ESG) factors into investment decisions does not harm financial returns and may even improve them. It challenges the myth that responsible investing leads to underperformance. The report also calls for a more systematic, quantitative integration of ESG into financial models and emphasizes the need for further academic research and ESG education for future investment professionals. The proportion of companies whose sustainability information is now part of stock market indices has increased dramatically—from 20% in 2011 to 93% in 2020 [6]. This surge reflects the recognition that sustainability is not merely a regulatory requirement but a core business driver. Reliable and standardized reporting enables stakeholders to assess performance, benchmark progress, and make informed decisions. However, while the volume of sustainability disclosures has grown, their quality, comparability, and practical usefulness remain uneven. Cheon [7] examines how ports balance economic and social goals, showing that the outcomes depend on stakeholder roles and organizational tensions. That study finds that sustainable performance varies by context and issue, urging ports to manage diverse stakeholder expectations carefully.

The 2019 Research Report by the Alliance for Corporate Transparency found that only 22% of the 1000 analyzed European companies presented their key performance indicators in a concise and easily understandable format, with 78% of the reports lacking practical usability [8]. These findings highlight a persistent gap between reporting practices and stakeholder expectations. The practice involves marketing or public relations strategies that make products, services, or policies appear more environmentally friendly than they actually are, often to attract eco-conscious consumers or investors based on the critically evaluated findings. This inconsistency has raised concerns among stakeholders, including investors, regulators, customers, and civil society, who are seeking sustainability information that is not only accessible but also comparable and harmonized across companies and sectors.

In this context, it is essential to explore how the port industry is adapting to the growing demands for transparency, quality, and comparability in sustainability reporting. This study aims to contribute to this effort by providing a structured overview of existing sustainability reporting guidelines, reviewing recent academic and industry literature to map the current state of research, and analyzing in depth the latest sustainability disclosures from major European and global port operators. The focus is on assessing the clarity and relevance of information provided in key areas such as environmental, health and safety, CO₂ emissions, energy efficiency, operational efficiency, social and ethics, and biosecurity/biodiversity indicators, collectively referred as E&S indicators in this study. Governance indicators were not included in the research due to the limited availability of data and confidentiality concerns surrounding executive decisions and compliance issues. Through this approach, this study seeks to assess how ports are navigating the sustainability imperative and to chart pathways for improving reporting standards—anchored in a precise location determination—to better meet stakeholder needs.

2. Research Methodology

The research was conducted in three main steps to evaluate current practices in sustainability reporting within the maritime sector. Initially, various frameworks, guidelines, and regulations were identified for developing a sustainability report. Subsequently, recent sustainability reports from the six largest EU container ports identified by the Port Economics group in 2021 [9] were reviewed. These ports include the Port of Rotterdam [10], Port of Antwerp [11], Bremenports [12], Piraeus Port [13], Port of Valencia [14], and Hamburg Port Authority [15], which collectively handled approximately 48.33 million TEUs in 2023. These 6 ports accounted for about 67% of the total container throughput among the top 15 EU ports, which handled 72.5 million TEUs in 2023. Additionally, sustainability reports from three major global players in the port industry were analyzed: the Port of Singapore Authority (PSA International) [16], Hutchison Port Holdings [17], and DP World [18]. This comprehensive approach allowed for the examination of sustainability information from over 100 container ports with a throughput of more than 300 million containers. An overview of the geographical distribution of the studied ports is presented in Figure 1.

The analysis of the reports involves identifying clear indicators from graphs, statements, and other information in the sustainability reports mentioned. During this process, the indicators are grouped together but not evaluated. To avoid double counting and ensure consistency, indicators with similar definitions that are used in multiple reports are treated as a single indicator. The goal is determine whether there is a consistent and unified approach to sustainability reporting in the port industry and to identify the number and types of indicators used as evidence of this harmonized approach.

Following this, a comprehensive review of the latest academic literature was undertaken, using targeted keywords to assess existing E&S sustainability frameworks and identify gaps and different reporting approaches. The literature search was performed across multiple academic databases, including Google Scholar, Scopus, and Web of Science, to ensure a comprehensive coverage of the relevant studies. A variety of keywords, including “Performance Indicators or KPIs”, “Environmental Performance Indicators or EPIs”, “Key Performance Indicators or KPIs”, and “Environmental, Social, and Governance or ESG”, were searched separately and in combination with terms like “Ports”, “Seaport”, or “Maritime” in order to find pertinent articles. Other keywords used to further cover ESG-related topics in port operations included but were not limited to the following: “Sustainability Practices in Ports”, “ESG Reporting Frameworks for Ports”, “ESG Port Practices”, and “ESG Challenges in the Maritime Sector or Ports”.

With the methodological framework established—comprising the identification of relevant sustainability reporting frameworks, the in-depth review of selected port sustainability reports, and a comprehensive literature analysis—the foundation was laid for a detailed examination of current reporting practices in the maritime sector. The following chapter presents the main findings derived from this multi-step research process. These findings are structured around the different dimensions of sustainability reporting, starting with an overview of the existing frameworks, followed by a discussion of the key reporting challenges observed and concluding with the analysis of the metrics used in the examined reports.

3. Findings

3.1. Sustainability Reporting Frameworks

Reporting on a company’s E&S sustainability status is not a new concept. Over the past few years, several organizations have developed different guidelines to assist the industry in fulfilling reporting obligations. Existing guidelines and reports can be broadly divided into voluntary guidelines and legally mandated regulations. Moreover, some major port operating companies have established their own internal sustainability reporting standards, which further complicate the landscape.

Some of the relevant organizations, documents and guidelines include the following:

• Global Reporting Initiative (GRI) [19];
• Green Marine Environmental Program, Performance Indicators for Terminals [20];
• PIANC, Sustainable Ports: A Guide for Port Authorities [21];
• Equator Principles [22];
• NASDAQ ESG Reporting Guide [23];
• World Federation of Exchanges ESG Guide and Metrics [24];
• Carbon Disclosure Project (CDP) [25];
• Sustainability Accounting Standards Board (SASB) Marine Standard [26];
• International Sustainability Standards Board (ISSB) within the IFRS Foundation [27];
• California’s Climate Corporate Data Accountability Act (SB 253) [28];
• EU Directive 2022/2464, Corporate Sustainability Reporting [29];
• IMO, Port Emissions Toolkit, Guide 1 [30];
• IMO, Port Emissions Toolkit, Guide 2 [31];
• IAPH, World Ports Sustainability Program [32];
• ESPO GREEN GUIDE 2021, a manual for European ports towards a green future [33];
• European Maritime Safety Agency (EMSA) [34];
• UN Sustainable Development Goals [35];
• International Social Security Association (ISSA) [36];
• International Labor Organization (ILO), Work and Social standards [37];
• ESRS–ISSB Standards, Interoperability Guidance [38];
• TFCD, Recommendations of the Task Force on Climate-Related Financial Disclosures, Final Report [39];
• United Nations Global Compact (UNGC) [40];
• Deutscher Nachhaltigkeitskodex (DNK), Leitfaden [41];
• ISO 14001, Environmental Management Systems [42];
• Environmental Management and Audit Scheme (EMAS) User Guide [43].

This vast number of available guidelines and recommendations gives a first impression of the diverse environment port operators face when looking for guidance to prepare their E&S reports. Only a few of them use comparable approaches and definitions, e.g., the new EU directive is inspired by the GRI guideline and the ESRS-ISSB Standard. It is important to note that internal reporting guidelines are not included in this overview, providing an initial indication of the variety of E&S reports and approaches available.

3.2. Metrics for E&S Reporting

There exist multiple methods for identifying and describing the E&S sustainability situation. In addition to quantifying data with numerical values or volumes, some information is referred to as performance indicators (PIs), while others are known as key performance indicators (KPIs). Other frequently used terms also include sustainability performance indicators (SPIs) and environmental performance indicators (EPIs). This variety in terminology can be, when naming one indicator with the same statement/focus in different ways, an indication of the absence of a common framework for identifying E&S information and measuring and reporting sustainability. In preparation for the elaboration of the EU sustainability standards, the Alliance for Corporate Transparency has released its “2019 Research Report”, which analyzes the sustainability reports of 1000 companies [8]. The primary finding of this research is that fewer than 22 percent of the companies provide their KPIs in summarized statements, while approximately 78 percent of the reports suffer from a lack of practical usability. In a report published in 2021 [44], the German Umweltbundesamt examined 477 environmental reports from German companies for the years 2018 and 2019. The report found that air pollution and biodiversity accounted for only 7% and 2% of the company indicators, respectively. Meanwhile, well-regulated areas such as water and waste, where indicators are strongly standardized by legislation, were only included in about one-third of all reports.

Xu et al. [45] investigate the alignment between corporate sustainability reporting (CSR) and stakeholder interests in China. Analyzing ESG reports from 48 listed firms and surveying 409 stakeholders, the study finds that while firms adopting the Global Reporting Initiative (GRI) standards disclose more sustainability activities, there remains a significant disconnect between these disclosures and stakeholder priorities. Specifically, companies tend to emphasize social initiatives aligning with governmental policies, whereas stakeholders prioritize governance-related risks, consumer protection, and environmental concerns. The study suggests that CSR practices in China are more influenced by regulatory compliance than by genuine stakeholder engagement, highlighting the need for firms to better align their reporting with stakeholder expectations. Moreover, Jámbor and Zanócz’s [46] systematic literature review examines the complexities and inconsistencies in environmental, social, and governance (ESG) reporting. The study highlights the diverse methodologies, subjective elements, and complexities involved in ESG’s measurement, leading to potential misinterpretations by companies relying on ESG ratings. It emphasizes the need for greater reliability in ESG ratings and reports to enhance credibility, transparency, and accountability. The review also points out that loose regulations, measurement complexities, and a lack of transparency contribute to greenwashing, underscoring the necessity for more stringent auditing and regulations in sustainability reporting and rating.

Meimaris [47] explores the growing significance of ESG reporting in shipping companies, emphasizing the pressure from regulatory bodies like the International Maritime Organization (IMO) and initiatives such as the Poseidon Principles. The study underscores that integrating ESG frameworks enhances transparency, manages environmental impacts, and strengthens competitiveness in the evolving market landscape. Similarly, Hummel and Jobst [48] analyze corporate sustainability reporting legislation in the EU, focusing on key frameworks such as the Corporate Sustainability Reporting Directive (CSRD), Sustainable Finance Disclosure Regulation (SFDR), and the EU Taxonomy. They discuss recent EU proposals to ease reporting requirements, which, while reducing regulatory burdens, have sparked debates over the EU’s commitment to its Green Deal targets. Expanding on this, Iozzelli et al. [49] examine the hybrid nature of the CSRD, highlighting how the EU’s blend of mandatory and voluntary reporting elements may lead to selective compliance, potentially undermining the directive’s effectiveness in driving substantial environmental, economic, and social changes. Turning to port sustainability, Özispa and Arabelen [50] address the lack of standardized Port Sustainability Indicators (PSIs) in sustainability reports.

Similarly, Kishore et al. [51] developed and validated an instrument to measure sustainability practices in Indian shipping ports. Their four-stage process, including expert evaluation and empirical testing, confirms the instrument’s effectiveness in assessing sustainability across economic, environmental, and social dimensions. Notably, they highlight that economic factors significantly drive the overall sustainability of ports by enabling investments in environmental and social initiatives. Examining broader corporate sustainability drivers, Ashrafi et al. [52] investigate the factors influencing sustainability’s adoption in maritime ports. Their multi-stakeholder analysis identifies key motivators such as regulatory pressures, economic incentives, and environmental concerns, providing insights for policy development and strategic planning in port operations. In the Canadian context, MacNeil et al. [53] highlight inconsistencies in sustainability reporting among Canada Port Authorities (CPAs). Despite their federal status, CPAs are not included in Canada’s Federal Sustainable Development Strategy (FSDS) and contribute to only 14 of 36 relevant UN Sustainable Development Goal (SDG) targets. To address this, the authors propose a port-specific sustainability framework based on Global Reporting Initiative (GRI) disclosures, offering a unified approach to align CPAs’ sustainability efforts with national and international sustainability goals.

Overall, metrics play a central role in E&S sustainability reporting, because they provide quantifiable data that form the basis by which organizations assess and report on their environmental, social, and governance performance. These metrics typically fall into three categories, numbers, indicators, and performance indicators, each serving a different purpose to measure and report on different aspects of E&S sustainability.

3.2.1. Numbers and Indicators

Collecting raw E&S data for sustainability reporting can be a time-consuming task. ESPO 2023 [54] identified, selected, and monitored ten environmental, social, and efficiency management indicators that provide information about the port’s management efforts regarding the environmental situation. However, the selected indicators, such as the existence of an environmental policy or an environmental monitoring program, show that they are being utilized as management tools and do not provide any insight into sustainability performance. More specifically, ESPO provides information on 11 monitored environmental parameters, including water quality, noise, port waste, and air quality. These parameters offer a broad overview of the environmental situation but may not capture the full complexity and diversity of environmental impacts.

Various ports also utilize specific indicators to measure their sustainability initiatives. For example, Piraeus Port [13] identified ten indicators in their report to evaluate the sustainability of waste management. PSA International [16] focuses on five indicators to describe their water sustainability efforts, while the Port of Rotterdam [10] implemented five indicators to track CO₂ emissions.

The scope of sustainability reporting varies significantly, from the simple counting of safety incidents to creating a comprehensive company inventory for CO₂ emissions. The IMO toolkits No. 1 [30] and No. 2 [31] provide strong guidance on how to create a holistic CO₂ inventory. However, Nielsen [55] suggests that the CO₂ KPI should be considered only as a fraction of the broader set of E&S disclosures. In addition, Hossain et al. [56] define sustainable initiatives as key sustainability indicators, ultimately identifying a total of 25 relevant indicators.

3.2.2. Performance Indicators

The existing literature highlights the broad range of PIs used across ports. Styladis et al. [57] identified 90 environmental indicators and 79 social indicators in their literature review but did not provide specific details on each. Brown [58] analyzed 26 ports and proposed a single port sustainability index based on metrics related to waste management, clean energy use, and air quality. Beyond management tools like ISO 14001 systems and straightforward metrics (e.g., CO₂ emissions), certain PIs are derived from detailed calculations or the connection between environmental impacts (e.g., emitted amount of CO₂) and operational metrics like goods throughput. These various PIs have different functions and can be customized to meet specific needs.

Di Vaio et al. [59] identified gaps in both the literature and practical application of PIs, prompting them to suggest new measurable indicators to bridge these deficiencies. Bang et al. [60] explored the challenges companies encounter when selecting and managing PIs. In the research conducted by Muangpan and Suthiwartnarueput [61], PIs were categorized into four distinct groups; however, none of these indicators were explicitly linked to operational factors such as goods throughput or output. Significant research gaps were also pointed out by Chen and Cheng [62], who emphasized the pressing need to standardize EPIs.

Hardianto et al. [63] observed a growing trend in port performance parameters. An analysis of the most recent port sustainability reports from six major EU container ports—Hamburg (2024), Bremenports (2022), Rotterdam (2023), Piraeus (2023), Valencia (2022), Antwerp (2020), and the global players PSA International (2023), Hutchinson Ports (2023), and DP World (2022)—revealed a total of 151 E&S PIs. These indicators include categories such as health and safety, environment, CO₂ emissions, energy efficiency, and operational efficiency.

3.3. E&S Reporting Challenges

The key problem of E&S reporting stems from the lack of standardization in reporting frameworks. While there are numerous guidelines on reporting, e.g., the Global Reporting Initiative (GRI) and the Sustainability Accounting Standards Board (SASB), in the absence of a unified standard, different reporting practices often emerge. This inconsistency presents a big challenge in assessing or comparing the E&S performance for stakeholders across organizations [64]. The complexity is further increased by a dynamic regulatory regime. The introduction of mandates such as the EU Non-Financial Reporting Directive forces organizations to implement a diverse and sometimes conflicting set of regional standards. However, frequent updates and changes to regulations create uncertainty, complicate compliance efforts, and increase administrative costs [65]. Moreover, with the newly revised and published European Sustainability Reporting Standards (ESRSs), the legal obligation will be quite new for some enterprises.

Another important challenge is financial constraints, which particularly hamper the activities of small and medium-sized enterprises (SMEs). Setting up a universal E&S reporting system needs a significant investment in data collection, auditing and reporting processes. The high implementation costs prohibit the full adoption of E&S frameworks by smaller firms, hence limiting their full potential to express their sustainability efforts [66]. Moreover, the applicability of universal indicators to SMEs can be an issue as well. Even for larger organizations, the quality and accuracy of data remain a problem. Many companies lack robust mechanisms to verify data, and hence inconsistencies occur that reduce the comparability and reliability of E&S disclosures. The absence of interdisciplinary expertise makes the issue more complex, limiting the gathering of precise and comprehensive information on environmental, social, and governance dimensions [67]. The risk of greenwashing is another critical concern [68]. Some firms try to improve their image based on appearances by touting their commitment to sustainability, even though their actions do not match that claim. This misleads stakeholders and also creates a notable credibility risk if any discrepancies come out between the reported metrics and actual practices. Accordingly, transparency and alignment of disclosures with actual sustainability initiatives are necessary to address the associated risk [68,69].

Measuring the social component of E&S reporting is highly difficult, because most relevant indicators, such as employee well-being, diversity, and community involvement, are subjectively interpreted. Unlike environmental indicators, which can be quantified, social indicators usually lack clear and standardized measures, a fact that complicates the reporting process and reduces comparability [64]. In addition, integrating these non-financial metrics with conventional financial reporting is difficult for many companies.

The apparent usefulness of E&S disclosures is undermined by the fragmented reporting that often results from the misalignment of E&S data with financial performance metrics [70]. An additional layer of complexity for organizations in developing a coherent E&S strategy arises from conflicting stakeholder expectations. Indeed, investors, regulators, customers, and employees may prioritize different dimensions of E&S, which creates a conflict of interest that causes inconsistencies in reporting procedures. This requires balancing different demands by using a subtle strategy for stakeholder involvement [71].

Operational barriers further complicate the effective implementation of E&S practices. Often, the effective adoption of sustainable business practices is only possible by making major changes to the supply chain, company policies, and even employee training. Internal resistance to such changes hampers progress, especially for those industries that have well-established operational processes. Prevailing over this reluctance requires strong leadership, along with a willingness to change existing business models [64].

In his 2025 study, Söylemez [72] assesses the operational, environmental, and social performance of container ports in Turkey, noting that only a small percentage of Turkish ports publish independent sustainability reports. The study highlights Mersin International Port as the leader in operational efficiency, while Socar Port excels in integrating all three sustainability dimensions. Using the MULTIMOORA method, the study evaluates and ranks ports based on their performance in these areas, drawing attention to the gaps in reporting and the need for further improvements. Supporting this, Lim et al. [73] conduct a systematic literature review, identifying key performance indicators (KPIs) to evaluate ports’ sustainability in terms of environmental, economic, and social dimensions. Their findings emphasize the increasing importance of sustainability in port operations and the need for integrated approaches to enhance ports’ performance. This notion of integrated practices aligns with Tseng and Pilcher’s [74] study on green port policies in Taiwan, which explores critical factors such as regulatory frameworks, environmental practices, and stakeholder engagement. Their research underscores the vital role of government support and leadership from port authorities in advancing sustainability initiatives. Further contributing to the conversation, Valenza and Damiano [75] investigate sustainability reporting and its role in enhancing public value within port authorities. Their work advocates for standardized reporting frameworks, enabling better transparency, accountability, and decision-making. In a similar vein, Roos and Neto [76] explore tools for evaluating environmental performance in Brazilian public ports, highlighting the necessity of integrating environmental impact assessments into port operations to improve ecological outcomes.

Moreover, Machado and Brazil [77] examine the role of operational indicators, particularly goods’ dwell time, in improving ports’ performance by reducing congestion and enhancing their throughput efficiency. Their research suggests the implementation of advanced tracking systems to optimize port operations. Similarly, Langenus and Dooms [78] advocate for the creation of an industry-level business model for sustainability in European ports. They argue for a collaborative framework that aligns environmental, social, and economic goals, stressing that integrating sustainability into ports’ business models is essential for their long-term competitiveness and success. Ashrafi et al. [79] explore corporate sustainability in Canadian and US maritime ports, highlighting key strategies such as investing in green technologies and fostering a culture of sustainability. They stress the importance of addressing environmental, economic, and social dimensions in port operations to achieve comprehensive sustainability. Similarly, González-Laxe et al. [80] provide a critical review of twenty years of sustainable development efforts by port authorities. Their study evaluates the evolution of sustainability policies and the challenges faced by ports in implementing effective sustainability initiatives. They also offer future directions for improving sustainability practices, emphasizing the importance of continued innovation and adaptation. Complementing this, Hardianto et al. [63] conduct a systematic literature review on port performance evaluation, focusing on the growing emphasis on environmental and operational efficiency metrics. They propose an integrated framework for assessing both traditional and sustainable performance measures across global ports, aiming to provide a holistic approach to evaluating ports’ sustainability. In a similar vein, Laxe et al. [81] analyze the relationship between economic and environmental indicators in the Spanish port system. They observe that while Spanish ports have made significant strides in economic growth, improving environmental sustainability remains a challenge. Some ports have successfully integrated eco-friendly practices into their operations, but more efforts are needed to achieve a balance between economic and environmental goals. Further contributing to the discussion, Hua et al. [82] evaluate green development practices in a Chinese seaport, emphasizing the importance of governance and regulatory frameworks in driving sustainable initiatives. They underscore that collaborative efforts between stakeholders are critical for achieving long-term sustainability goals in port operations. This aligns with Teerawattana and Yang’s [83] case study on Laem Chabang Port, which explores the use of environmental performance indicators to evaluate green port policies. Their findings suggest that while these indicators help track sustainability goals, challenges remain in integrating them into broader operational and policy frameworks. Lastly, Liu et al. [84] examine the sustainability of an industrial park using a combined evaluation method, highlighting the importance of integrating environmental, economic, and social factors. They conclude that sustainability in industrial parks, including ports, depends heavily on collaborative approaches among stakeholders, further supporting the notion that cooperation is key to successful sustainability efforts.

The works by Antão et al. [85], Puig et al. [86], and García-Onetti et al. [87] contribute to the discussion on sustainability in port operations by addressing occupational health and safety, environmental performance, and integrated management approaches. Antão et al. [85] focus on occupational health, safety, and security (OHSS) and environmental performance indicators in port areas. They propose a structured set of indicators that can enhance safety standards and environmental sustainability, ultimately improving the overall performance of ports. This emphasis on safety and environmental responsibility aligns with the findings of Puig et al. [86], who examine benchmark dynamics in ports’ environmental performance. Puig et al. highlight the importance of setting realistic, region-specific benchmarks, allowing ports to achieve sustainability improvements that are both feasible and effective. Building upon these ideas, García-Onetti et al. [87] emphasize the need for an integrated, ecosystem-based approach to port management. Their research underscores the necessity of embedding environmental considerations into port governance, ensuring that sustainability goals are not treated as separate initiatives but as core components of port operations. This holistic perspective helps ports not only comply with environmental regulations but also develop more sustainable and resilient business models in the long run.

To sum up, recent research underscores the increasing global focus on embedding sustainability into port operations by assessing performance across environmental, social, and economic dimensions. These studies emphasize the need for standardized reporting, advanced operational indicators, and government or stakeholder collaboration to improve sustainability performance. Across different regions—from Turkey to Canada, Spain, and China—researchers consistently advocate for integrated frameworks and governance approaches that embed sustainability into the core of port management and strategies. However, despite these efforts, investor skepticism remains a persistent issue. Even though E&S investments are becoming more and more popular, many investors doubt the credibility of E&S claims because of the lack of transparency and uncertainties surrounding data accuracy [88]. Addressing these interrelated problems is highly important for increasing the reliability and effectiveness of E&S reporting and, consequently, supporting organizations in truly demonstrating their commitment to sustainability.

3.4. Clustering of Sustainability Indicators

Sustainability practice reports generally group various metrics into specific clusters to better track and optimize performance. These indicators are essential for organizations to align their plans with sustainable development goals. Each cluster addresses different dimensions of sustainability and facilitates the achievement of organizational sustainability objectives in a focused manner.

Table 1. Sustainability clusters and number of indicators.

Sustainability Cluster	No. of Indicators
(a) Environmental	28
(b) Health and Safety	25
(c) CO2 Emissions	22
(d) Energy Efficiency	27
(e) Operational Efficiency	17
(f) Social and Ethics	28
(g) Biosecurity/Biodiversity	4
Overall	151

provides an overview of the sustainability clusters and the corresponding number of indicators from the analyzed six largest EU ports and three large worldwide port operator sustainability reports.

Below is a synthesis of insights relevant to each category based on current research.

(a)

Environmental: Environmental sustainability indicators are those that deal with the optimization of resource use, along with the minimization or reduction of pollution. This scope is highly relevant to the efficiency and sustainability of operations. The adoption of integrated energy systems, including renewable energy sources, can significantly reduce CO₂ emissions across sectors, emphasizing eco-friendly resource use [89]. Additionally, ISO 14001-certified companies demonstrate how environmental indicators contribute to the management of resources in a sustainable way and lead to achieving conformance to regulatory standards [90]. However, Rodrigues et al. [91] and Lalla-Ruiz et al. [92] emphasize the ongoing need for further harmonization to determine the optimal set of environmental indicators for evaluating the environmental performance of port organizations;

(b)

Health and Safety: Health and safety indicators are crucial in sustainability frameworks for reducing risk in hazardous industries. Bioenergy systems exemplify the integration of health and safety into sustainable operations, especially to benefit marginalized communities by providing access to clean energy [93];

(c)

CO₂ Emissions: Efforts to reduce CO₂ emissions are central to sustainability clusters. Research indicates that investing in R&D for low-carbon technologies provides a better balance in reducing emissions and is, therefore, prioritized in developed regions. A good example would be how such actions have helped the European Union towards sustainability and economic growth up to now;

(d)

Energy Efficiency: Energy efficiency clusters improve the sustainability of production and reduce costs across industries. For example, the efficient use of energy in small industry clusters improves both their environmental performance and operational efficiency, emphasizing the role of efficient energy management for industries on a small scale [94];

(e)

Operational Efficiency: Operational productivity indicators aim to increase productivity, while minimizing energy consumption and waste. The manufacturing sector has adopted sustainability assessments to improve environmental efficiency by reducing energy and water consumption, as well as hazardous waste. This, in turn, lowers operating costs and environmental impacts [95];

(f)

Social and Ethics: The social and ethical cluster in the framework of sustainability encompasses the practice of equity in labor issues, welfare within the community, and corporate responsibility. Social responsibility is emphasized by standards such as Fair Trade and the Rainforest Alliance, which promote ethical work practices alongside environmental protection efforts [96,97];

(g)

Biosecurity/Biodiversity: This cluster includes biodiversity protection indicators that are necessary to prevent ecosystems’ degradation. In order to safeguard regions of high conservation value and stop activities that endanger ecosystems, sustainability guidelines incorporate biodiversity criteria [98]. These measures are particularly important for the operation of seaports to reduce the potential negative impacts on the environment that arise from various factors such as pollution, habitat loss, and the introduction of invasive species, and to guarantee that the ecosystems remain resilient and sustainable in the future.

4. Conclusions

E&S performance indicators are crucial for assessing and improving ports’ sustainability by developing a framework through which operations can be oriented towards environmental and social (E&S) goals. Moreover, they allow ports to address both operational efficiency and sustainability as main priorities in a harmonious manner for stakeholders, investors, regulators, customers, and civil society. The practice of using 151 different indicators based on 25 different relevant organizations, documents, and guidelines shows the abundance of options when creating a sustainability report. An increasing number of used indicators can go hand in hand with an increasing risk of greenwashing.

The variety and complexity of E&S performance indicators and reporting systems present challenges in achieving consistency and comparability across ports. The standardization of PIs, along with the integration of environmental and operational dimensions, is important in ensuring that sustainability-related assessments are holistic. By customizing E&S PIs to the particular operational strategies and improvement actions of each port, it becomes possible to meet specific sustainability goals while remaining in line with broader global benchmarks.

Efforts to harmonize E&S reporting standards and provide integrated and adaptive PIs would boost the contribution of the maritime sector to sustainable development. Integrating environmental, social, and operational factors into performance assessments can give rise to increased resilience, greater transparency, and an effective contribution towards global sustainability objectives for ports. Future research should be directed more towards optimizing data-gathering methods, promoting real-time insights, and further applying digital technologies to make sustainability reporting and the evaluation of performance easier.

Apart from that, there is an urgent need to assess the standardization of E&S reporting aspects across different organizations, documents and guidelines to ensure comparability and accountability on a global scale. Further studies on how new technologies, such as artificial intelligence and machine learning, are capable of improving the collection and analysis of sustainability data would also be extremely useful. The combined partnership of academic researchers, industry stakeholders, and policymakers is necessary to build effective and strong E&S frameworks addressing the marine industry’s dynamic issues. Moreover, studies examining the long-term impacts of E&S practices on ports’ performance and the broader global supply chain will be crucial in assessing the true effectiveness of these initiatives.