1 Introduction

The history of computer innovation shows that the emergence of new technologies affects human lifestyles and fundamentally transforms the way humans interact with computers. One of such technologies in society today (or in the near future) is the metaverse.

The concept of the metaverse, from a historical point of view, was introduced in 1992 in Neal Stephenson’s science fiction novel Snow Crash [1] and attracted attention from some people such as educators; however, it has not attracted so much public attention as it does today [2]. When Facebook changed its name to Meta in 2021 and declared a new era of social interactions through the metaverse, it gained substantial public attention and was popularised broadly [3].

There are different ways to define the metaverse from different angles. According to Mystakidis [4], the metaverse is based on the integration of technologies such as Virtual Reality (VR) and Augmented Reality (AR) that enable multisensory interactions between virtual environments, digital objects, and humans. In contrast to this technology-focused view, Park [5] presents a more social perspective on the metaverse, arguing that the essence of the metaverse should be understood as service with social meaning and sustainable content rather than as applications of such Extended Reality (XR) technologies as usually conceived. The metaverse has also been recognized as a platform for the next generation of social connection and networking [6]. The metaverse in a mature form is expected to combine a variety of technologies, such as XR, blockchain, AI, and cloud computing, in an integrative manner, thus yielding new forms of human–computer interactions that are more immersive, intuitive, and seamless [7].

In this paper we thus shed light on human-computer interactions in the emerging age of the metaverse. New forms of human-computer interactions enabled by the metaverse are beneficial for humans in many ways; at the same time, however, there are social issues that are emerging as the metaverse develops and that need to be taken seriously. Specifically we focus upon issues such as security and privacy, surveillance capitalism, cyber-syndromes, amplification of social problems, and environmental problems, and discuss what regulations would be appropriate in order to balance the adequate development of the metaverse with the safety and security that is required for social good and sustainable development goals. We finally propose ethical design principles for the sustainable metaverse to address the aforementioned and other social issues.

The rest of the paper is organized as follows. In Sect. 2, we analyze human-computer interactions in the metaverse from two points of view (namely, Access/Display and Perception/Input). In Sect. 3, we propose the metaverse as infrastructure and discuss some issues in the metaverse, such as security and privacy, surveillance capitalism, cyber-syndromes, and amplifications of social problems. In Sect. 4, we propose and discuss ethical design principles for the sustainable metaverse. We conclude the paper in Sect. 5.

2 Human–computer interaction on the metaverse

We analyze human-computer interaction on the metaverse through the two points of view of “access and display” and “perception and input” [8] in the following manner.

2.1 Access and display

The first point of view concerns devices and technologies that enable access and display a heightened sense of realism within the virtual world. Specifically, access and display on the metaverse are supported by Extended Reality (XR) technologies, and XR encompasses Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR). XR is implemented through those devices, such as smart glasses, that enable access and display for extended realities [7, 9]. Each of AR, VR, and MR has its distinct characteristics, which we delineate below, while all of them share the common goal of improving user experience [10, 11].

AR creates interactive experiences via the integration of digital information with the real world [12, 13]. For example, AR allows us to interact with virtual objects within the real world and receive augmented information (e.g., visual effects). Put differently, we receive augmented information from the virtual world while the base of communication is in the physical space.

VR immerses users in a fully simulated digital environment separated from the physical world [10], allowing user experience with increased immersion, realism, and embodiment through specialized devices such as head mount display to the extent that users themselves are elements of the metaverse.

MR integrates digital content into the user’s physical environment, thus creating a very realistic augmented world [10, 14]; MR may be considered synonymous with AR [15]. MR, from another perspective, merges both AR and VR in that it is primarily based upon the real world but at the same time integrated with the virtual world [16]. MR enhances user experience by providing a more immersive way to interact with virtual content in the real world (Fig. 1).

Fig. 1
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AR/VR/MR

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XR technologies create an immersive world that blurs the boundaries between physical and digital realms and allows humans to escape from the physical constraints and feel a living synthetic digital environment, which is an essential element for the realization of the metaverse. There is some debate among certain experts regarding the timeline for the full realization of XR, with some asserting it will be achieved by 2040 [17].

2.2 Perception and input

According to Wang et al. [8], scanning the real world and reconstructing it in the virtual realm with high reliability is crucial for the metaverse. This requires accurate recognition of user perception and understanding of input information.

Technological advancements, including wearable devices and sensors, provide the means to achieve this. For example, within this digital landscape, biometric identifiers such as facial and fingerprint scans play a pivotal role in user authentication and personalized profile creation. Additionally, leveraging biometric identifiers enhances immersion by translating facial expressions and body movements into avatar behaviors and emotions, thereby fostering more authentic communication within virtual environments.

As information is transitioned from the physical realm to the metaverse, it becomes subject to real-time monitoring and recording, transforming every aspect within the metaverse into data. The richer the human-computer interaction, the more data is collected through the interaction, which is considered important information that can then be analyzed and used to optimize the user experience.

3 Social implications of the metaverse

It is crucial to define the conditions of the metaverse as a prerequisite before clarifying the social meaning of the metaverse. This is because it remains to be seen whether the metaverse will ultimately function as a mere affordance or evolve into a more comprehensive infrastructure. For example, according to Nagy and Neff’s theory [18], the metaverse can be understood as a new field of interaction between the physical and digital worlds, providing a variety of affordances based on user expectations, perceptions, emotions, and social context. On the other hand, there is also an idea that the metaverse can function as an infrastructure rather than merely as an affordance, which is how we see it. We consider that the metaverse eventually becomes a complete infrastructure, in other words, an artificial general universe (AGU). It means that the metaverse is implemented as a basic everyday structure and system for everything from social activities to politics. If the metaverse plays such a role, it means not only tools and platforms but also the basic infrastructure of education, healthcare, business, public services, etc.

At present, humans are constrained by both internal and external conditions. AI robots can transcend the limitations of the human body and cognition, which come from the limitations of the environment and, ultimately, the universe, respectively. But at the same time, even AI and AGI robots are constrained by the conditions of the environment and its laws, and ultimately the universe and its fundamental laws. Although the metaverse is still in its developmental stages, we consider its potential to be as great as that of AI: just as AI will evolve into AGI, so will the metaverse evolve into an Artificial General Universe (AGU). Of course, some perspectives are skeptical of this view. Heisenberg’s uncertainty principle is one example, it says that simulating our universe is impossible, as far as our knowledge of the laws of physics goes. Even so, we take the position that the metaverse could be a digital twin of the entire physical universe, and could be designed as an entirely separate universe with new physical laws. When such an era arrives, all the physical constraints that intelligent agents have had to face up to now will be eliminated or controlled, and intelligent agents will accordingly be freed from the conditions of the real world.

With the premise that the metaverse can function as digital twins, we begin to outline the challenges associated with the metaverse. The diagram below illustrates an overview of metaverse challenges categorized according to the framework of social, environmental, and economic factors (Fig. 2).

Fig. 2
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Overview of metaverse challenges

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3.1 Security and privacy

The metaverse gives rise to data privacy and security risk issues as does the Internet [19]. We consider that the collection and use of personal data by companies operating the metaverse may lead to an ever greater impact on personal privacy and security.

One of the reasons is that the amount of information in the metaverse increases. The metaverse requires a significant amount of personal information to build a personalized and immersive world for users [20]. In addition, all kinds of information, including human five senses information, can in principle be acquired and used in the metaverse. For example, the security for hardware like VR contains lots of sensitive information such as user’s biometrics and motion data, which is potentially dangerous for privacy because of the data leakage.

Secondly, there are abundant opportunities for hackers to steal information due to the high volume of transactions within the metaverse. For example, the metaverse creates a virtual economy, which is the so-called “metaverse economic zone", where a wide range of economic activities take place, including digital assets such as virtual currencies and Non-Fungible Tokens (NFTs).

Thirdly, the metaverse is still in its developmental stage, lacking robust governance structures. While some companies have made efforts to build well-maintained platforms and protect users’ data, the theft or leakage of users’ personal information has continued to occur. Privacy and security concerns regarding the handling of personal information and digital assets within the metaverse would be raised against the platformer, which could affect the trust and safety of the community in the metaverse.

Stolen data can be sold to third parties or misused for fraud. Any data can be an extremely valuable resource for some people. For example, voices are increasingly being stolen and used for fraud purposes. AI enables scam groups to simulate people’s voices based on a small amount of their voice samples. According to Washington Post [21], impostor scams were the second most popular racket in America in 2022 and 5,100 of those incidents happened over phones. Since the metaverse is a treasure trove of data from which sensitive personal information can be obtained, including voice information, it is necessary to consider the possibility that it will be used for criminal purposes in the future. Furthermore, the recent emergence of generative AI is likely to accelerate this trend, presenting a significant opportunity for fraudsters. The technology significantly increases the feasibility and prevalence of voice-based fraud, it could also undermine advanced fraud prevention measures like voice authentication [22].

3.2 Surveillance capitalism

Surveillance capitalism refers to a socioeconomic system that pursues profit by collecting and monitoring personal data [23]. The concept involves tracking individuals’ online activities and behaviors, where personal data is treated as a commodity and companies collect it and use it for marketing and advertising purposes [24]. As described above, the immersive and addictive nature of the metaverse; that users are expected to spend a significant amount of time there, which accordingly will increase the total amount of information collected. In addition, most of our information, from sight, hearing, speech, body movements, and perhaps even the content of our thoughts, can in principle be acquired in the ultimate form of the metaverse (even if there are still limitations on the types of data that the current metaverse can collect). Hence, we anticipate that surveillance capitalism will accelerate within the metaverse and bring about some challenges.

First, accumulated data increases cybersecurity risks. If these databases of sensitive national and other information are targeted for hacking or cyberattacks, national security could be seriously affected. Gina Neff interviewed in [17] warns that the metaverse accelerates surveillance capitalism and it would limit the ability of regulators and the state to protect individuals and concentrate power in the hands of corporations.

Surveillance capitalism may also have implications for the free decision-making of the user. For example, regarding terms of service, taking advantage of the fact that customers do not read the terms and conditions in detail, data may be obtained under various conditions and used to pursue further profit and power, such as buying and selling to third-party organizations. In addition, companies use individual decisions and choices can be influenced by marketing and advertising manipulation as data collection and analysis enable prediction of individual behavior and preference (and individually tailored information and content are presented). If filter bubbles may be formed, narrowing users’ choices or minds themselves. The manipulation of customer behavior by the companies has been discussed in the AI ethics context as well. According to Zuboff [25], companies seek to maximize profits and achieve market dominance by predicting and manipulating customer behavior.

Thirdly, the commodification of humans that occurs when metaverse platforms monitor human behavior is an important topic in the context of surveillance capitalism. For example, in the metaverse, users can perform various forms of labor, which can be viewed as part of economic activities that create value, just as in the real world. In addition, labor on the metaverse can be regarded as a way for the platform to learn the behavioral patterns of workers on the platform, which in turn learns a lot of data about the user’s labor patterns, efficiency, quality of deliverables, and so on. By analyzing those data, companies can use it to optimize labor and build new business models. If the market determines the organization of labor, there is a danger that workers will be considered mere accessories to machines in important sectors of the economy [26]. Such work environments can be detrimental to workers’ psychological and emotional health. Therefore, the commodification of humans in the metaverse must be carefully considered from an ethical perspective.

Amidst concerns surrounding security, privacy, and surveillance capitalism, we are prompted to question why the trend of organizations collecting and retaining excessive amounts of personal data is accelerating. According to Doctorow [27], there are three reasons for this. Firstly, companies must use a variety of methods to increase sales because of consumers’ growing ability to resist. Competitors are also using data to compete, so companies need to understand and manipulate customer behavior. Secondly, since data collection and storage are relatively inexpensive and become an asset in the future, organizations find it beneficial to continue to aggregate and retain data. Thirdly, organizations can take the risk of continuing to retain data since the penalties for data breaches are currently not fatal [28]. Put simply, the current digital environment demands that companies and organizations collect as much data as possible. Data is seen as an important resource for increasing a company’s competitiveness and profits, and this tends to drive the collection of data. Weak penalties for data leaks and compromises also drive the trend toward data collection. When penalties are minor, companies and organizations can take the risk of continuing to collect data, and thus data collection is becoming increasingly widespread in society.

3.3 Cyber-syndromes in the metaverse

The immersive nature of the metaverse can make people addicted to it and may lead to what are generally called cyber-syndromes. A cyber-syndrome is a physical, social, and mental disorder that affects humans due to the misuse of technology and excessive interaction with cyberspace [29]. Cyber-syndromes in the metaverse can be even more dangerous than cyber-syndromes observed through the traditional use of the Internet. Cyber-syndromes can be divided into three categories, physical disorder, social disorder, and psychological disorder.

3.3.1 Physical disorder

With regard to physical issues, the highly addictive nature of the metaverse can cause the following health problems for users. For example, the smartphone-based metaverse requires users to stay in the same position for long periods. This can lead to the text neck syndrome (a postural problem that causes neck pain and tension) [29, 30]. By keeping the head and neck down and looking at the screen, the muscles in the neck and shoulders become tense, causing pain and discomfort. Other symptoms such as eye strain and headaches may also be suffered [31, 32]. (It should be noted that these and the following physical issues are not necessarily problems specific to the metaverse; just for completeness we still mention them briefly.)

It is also possible that over-dependence on the metaverse can lead to sleep deprivation. Spending extended periods in the metaverse leads to increased screen time and blue light screens may suppress the production of melatonin, a sleep-regulating hormone, which can disrupt the body’s natural sleep-wake cycle and make it difficult to fall asleep [33]. The metaverse also offers immersive and interactive experiences that are mentally and emotionally stimulating, such as combat game worlds. Intense or stimulating activities before bedtime can make it difficult to relax and unwind, making it difficult to fall asleep.

Engaging in virtual activities in the metaverse often involves prolonged periods of sitting and limited physical movement. It does not provide users with the same opportunities for exercise and movement, at least not in the same way as in the real world. This sedentary and inactive behavior can lead to reduced physical activity levels and metabolic problems such as weight gain [34].

3.3.2 Social disorder

The virtual and digitally mediated nature of the metaverse can affect interpersonal skills. In the metaverse, people interact with each other through avatars and digital representations, and then they may not fully grasp the nuances and complexities of face-to-face communication in the real world. As a result, they may lack the practice and development of nonverbal cues, body language, emotional intelligence, and other interpersonal skills essential for effective communication and relationship-building in the real world. Furthermore, spending excessive time in the metaverse may reduce opportunities for social interaction in the real world. People may become immersed in virtual relationships and communities, neglecting offline connections and social responsibilities. In addition, the metaverse can limit the depth and quality of interpersonal relationships. Communication in virtual environments, with current technology, often relies on text-based or limited audiovisual communication, which may not have the richness and nuance of face-to-face conversations. As a result, it may not be possible to sufficiently develop the ability to communicate with others.

People in the metaverse can feel socially isolated. First, the metaverse is a virtual environment, and while it is possible to interact with others, there is no physical connection as experienced in the real world. Second, the metaverse is often disconnected from real-world identities, and people using avatars or pseudonyms should feel a lack of meaningful tangible connection, feeling as if the individual is interacting with an unrealistic facade rather than a real personality. In addition, the metaverse may limit the depth and quality of interpersonal relationships, resulting in shallow or superficial interactions that may not satisfy the individual’s desire for deep emotional connection and meaningful relationships. Besides, those who spend excessive time in the metaverse may experience a diminished sense of community and belonging in the physical environment. This can contribute to a sense of isolation and detachment from the real world.

3.3.3 Psychological disorder

The metaverse can have negative psychological effects. Metaverse experience may trigger delusional disorder. For example, users who engage in a virtual war in the metaverse may have psychological or physical damage even in the real world, since the metaverse provides a more realistic experience than playing in a traditional screen-based medium. It can even lead to a lack of distinction between reality and the real world after returning from the metaverse, which can cause trauma and anxiety. Overuse of computer technology is thought to be associated with mood disorders such as depression and anxiety among adolescents [35,36,37], and the immersive nature of the metaverse can exacerbate these problems.

The metaverse may also cause FOMO (Fear Of Missing Out) [38]. The metaverse often operates always, with a continuous flow of information, making it hard to miss out on relevant information such as social trends and technical skills. When users see others building connections and engaging in exciting activities in the metaverse, they may fear that they will be excluded or isolated if they do not actively participate.

3.4 Widening inequalities

Artificial intelligence boosts productivity and generates wealth, yet it has not reduced the gap between rich and poor due to uneven distribution of its benefits [39]. Moreover, the metaverse exacerbates the disparity between individuals who possess access to advanced technology and those without.

We need not only minimal infrastructure to access the Internet but also expensive VR goggles and other gadgets to make ourselves an immersive environment. For example, the popular VR Google, Meta Quest 3.0 starts at US$499.99 [40] and PlayStation VR2 at US$549.99 [41]). This is a heavy burden for those with financial hardship. Those with access can seize opportunities to thrive in the metaverse, leaving those without access behind. It is because once the initial access hurdles are surmounted, a positive cycle of platform opportunities emerges, enabling access to resources including educational content, acquiring the essential skills, leveraging those skills in the metaverse market, and ultimately making money. Thus socioeconomic disparities in the real world are reflected, perpetuated, and reinforced in the metaverse, and those individuals who have better access to it will have more opportunities, privileges, and advantages. This can exacerbate existing inequalities and create additional digital divides [42].

3.5 Metaverse harassment and bullying

Issues such as harassment and bullying have appeared in the metaverse. Certain issues are magnified within the metaverse, becoming more severe compared to the traditional internet.

One main factor is the increased place for negative conduct, as the metaverse serves as a platform where individuals can potentially engage in detrimental behaviors, introducing new opportunities for misconduct.

Second, the metaverse is often used anonymously, and aggressive behavior is heightened in spaces where anonymity is high [43]. The anonymity of the metaverse makes it easier to speak up, and there is also the aspect of not being able to see the other person’s face in reality, and these factors contribute to aggression.

Thirdly, the boundary between reality and the virtual realm becomes blurred due to features of the metaverse, allowing users to potentially carry existing problems into this digital environment. Some of these issues are more serious than in the traditional web. Sexual harassment, in particular, individuals may encounter more realistic experiences in the metaverse, as users can physically interact with each other. This tactile dimension makes the impact on the victim feel more tangible and makes the discomfort. The current legal system and norms are not prepared to deal with these new problems, so new regulations and measures are needed [44].

3.6 Prejudice and discrimination

The exacerbation of social prejudice and discrimination within the metaverse will be predicted. It includes not only visible intentional actions but also unintentional actions resulting from the structure of the metaverse itself.

Intentional action is, for example, hate speech, and discriminatory behavior among users. Unintended biases are introduced into the metaverse during the process of constructing its environment. For instance, the data utilized to construct virtual settings and interactions often originate from real-world sources containing inherent biases and harmful societal norms. Consequently, the metaverse environment may inadvertently reflect these biases and reproduce prejudice and discrimination. Ensuring that the data used to create metaverse technology is diverse, representative, and unbiased is essential, but achieving this as a norm is currently very challenging. Many IT companies continuously receive feedback from customers regarding biased outcomes generated by their systems, prompting them to engage in ongoing efforts such as deletion, adjustment, and educating the systems.

3.7 Energy problem

The rapid growth and widespread adoption of the metaverse and its technologies may cause environmental problems, with energy consumption emerging as a significant concern. Carbon neutrality, which is one of the global action plans to deal with rising global greenhouse gas concentrations and temperatures, is a vital perspective when we have to consider environmental problems. It is necessary to not only reduce carbon dioxide emissions but also to remove carbon dioxide from the atmosphere to achieve net-zero carbon or negative carbon emissions through various social, economic, environmental, and technological measures [45]. It is true that the metaverse can play a role in reducing the amount of emission of transportation, manufacturing, and energy generation [46]. For example, the metaverse curbs emissions through activities such as holding virtual meetings instead of in-person meetings. According to Tao et al., [47], shifting physical meetings to virtual meetings can reduce carbon emissions by as much as 94 %. At the same time, however, the metaverse utilizes advanced graphics and processing power, causing carbon dioxide emissions through activities such as streaming and transactions, which potentially affect global warming [48]. Thus, there is a trade-off between the amount of carbon dioxide emitted by the metaverse and the amount of carbon dioxide that can be reduced by using the metaverse. How to manage energy consumption by the metaverse to maintain or reduce carbon emissions is important.

3.8 Digital waste

As the information industry grows, there is a tendency for the amount of digital waste to increase. E-waste/WEEE (Waste Electrical and Electronic Equipment) has increased so far and poses a serious challenge in disposal and recycling for both developed and developing countries [49]. The more widespread the metaverse becomes, the more e-waste such as VR goggles will be generated in the future, requiring proper waste management. Moreover, failure to manage them could lead to health problems due to the hazardous substances they contain. Issues arise not only from hardware waste but also from software concerns. For example, data accumulation in the metaverse leads to increased costs associated with increased data storage and the presence of unnecessary data can degrade overall system preferences.

3.9 Water problem

As the energy consumption increases, so does the water demand. The rapid growth of the Internet has accelerated the demand for the data center which is a facility or building where servers are securely stored. According to [50], data centers in 2022 account for 1–1.5% of global electricity consumption. These days, many new data centers were constructed, in 2023, data center construction in major markets will be the largest ever [51]. Each data center requires many high-performance servers to process large amounts of data at high speed, which accelerates power consumption and heat generation, resulting in high temperatures inside the data centers. For high temperatures, these data centers require significant cooling facilities. Data centers use large amounts of water for cooling, which increases the load on water resources.

3.10 Governance, regulation, and accountability

Ethical and responsible design of developing technologies raises a wide range of issues. Even though there is a need for a legal framework and proper governance to promote ethical use of technology and prevent misuse, no clear governance or regulation of the metaverse exists at this moment.

Firstly, governance, including economic governance, political governance, social governance, and so on, depends on platforms. However, users come from diverse backgrounds, and there is a need to establish a governance that can be universally applied across countries.

In addition, universal regulation should also be considered in the event of incidents or fraud within the metaverse. For example, we would encounter new issues in the metaverse and have to develop legal procedures and penalties for misconduct in the metaverse.

Finally, especially important to establish accountability within the framework. As information systems become more integrated into various industries and applications, questions have been raised as to who is responsible for the actions and results of these systems [52]. It is not clear who is responsible for what in the metaverse. For example, suppose there is a human living there as an avatar, and the avatar has done something wrong. Should we punish the human in the real universe directly, or just the avatar in the artificial universe? In current society, responsibility for information systems is primarily attributed to human entities, based on laws and rules established by humans [53]. Whether or not this principle can be applied to the metaverse is one of the questions.

When we think about governance, regulation, and accountability, the controlness is an important factor. How much autonomy to assigned to algorithms with the premise that the metaverse can be the perfect infrastructure? AI systems ultimately can make decisions without human intervention, and the metaverse is expected to overflow with such autonomous decision-making if we do not control [39]. Even now, when we are primarily a general artificial intelligence, not up to a general artificial universe, AI’s black box algorithms stop us from finding out what causes us to do what we do. We need to understand how algorithms come to certain conclusions and decisions [54]. Then the concept of the explainable algorithm (which is also referred to as white algorithms) makes the inner workings of a model transparent and understandable to humans and is recommended. However, the metaverse could be an autonomous universe (although current metaverses are not), and would even be able to design its laws and rules by itself, serving as the governor of the artificial universe, which may still sound like a fantasy, but there are related ideas such as algorithmic politics (cf. [55]), which could improve upon human politics.

4 Ethical design principles for the sustainable metavers

In this section we propose ethical design principles for the sustainable metaverse from environmental, economic, and social perspectives. We refer to the vision of a virtual universe or digital ecosystem that is developed and operated in a manner that prioritizes long-term environmental, social, and economic sustainability. Our goal is to create and maintain a virtual space that balances technological advances and immersive experiences with responsible and ethical practices (Fig. 3).

Fig. 3
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Ethical design principles

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4.1 Environmental perspective

From an environmental perspective, we explore ways the metaverse can contribute to resource efficiency and conservation. First, the metaverse has the potential for energy savings by creating digital twins within the metaverse. For example, conducting virtual meetings and activities instead of physical activities are ways in which the metaverse can conserve energy. At the same time, however, the operation of the metaverse is believed to have large amounts of carbon footprint. For instance, the carbon footprint of high-quality streaming, 3D, and other features, as well as emissions from data centers and servers. Therefore, the core principle of addressing environmental concerns involves enhancing energy efficiency and integrating renewable energy sources to offset excess energy consumption. Promoting sustainability through environmentally conscious design and optimization of metaverse platforms and applications is important. Using efficient metaverse infrastructure is among the key perspectives. The introduction of optimized algorithm structures and renewable energy sources for the infrastructure is essential. Regarding algorithms, the consensus algorithm known as "proof of stake" is much less energy-intensive, making it the preferred choice for large-scale NFTs that will support Web3 and the metaverse [39]. As for servers and networks, energy efficiency and environmental considerations are the key, and the introduction of solar energy, wind energy, storage batteries, and so on is considered the most realistic option. In addition, Google is working on a geothermal power project, which presents a potential future option for geothermal power generation [56].

Overcoming the digital waste like e-waste problem requires sustainable hardware; manufacturers of XR equipment must prioritize sustainability in their production processes, which includes using environmentally friendly materials, promoting recyclability, and minimizing the use of hazardous substances. For water waste, it can be reduced by using reclaimed water for uses that do not require the use of clean water, such as in data centers. In addition, to fundamentally reduce the amount of water used, the cooling method should be substituted with other technologies. As a notable trend, liquid cooling has emerged and is expected to gradually become the core of the cooling field. Liquid cooling technology refers to a technology that uses liquid as a refrigerant instead of air to exchange heat with and dissipate heat from heat-generating components such as the CPU, chipset, RAM, and expansion cards.

Education and enlightenment are fundamental but important methods to achieve a sustainable metaverse. Education on environmental issues is an issue that must be addressed by multiple stakeholders in a coordinated manner. For example, commercial platforms can provide awareness campaigns and interactive learning tools on a large scale, in that they have massive reach and technical resources. Governments and non-profit organizations can provide the framework and funding for educational programs. Schools, families, and platforms can promote comprehensive environmental education within that framework.

4.2 Social perspective

From a societal perspective, we examine approaches to the above issues and explore potential solutions that should be pursued to make the metaverse an inclusive and safe environment. First, in order to make the metaverse a safe place, strict legislation against violence and harassment at the production level is necessary. In addition, to prevent the exacerbation of harassment, bullying, and other harmful behavior on the metaverse, platformer could automatically exclude or display users and utilize reporting systems to curb abusive behavior. It may also be necessary to implement systems to regulate usage to ensure the digital well-being of users. These include screen time controls to prevent problems such as metaverse addiction, highlighted by cyber-syndrome. These automated functions would need to be actively managed by the platformer.

In addition, we should create an inclusive and non-discriminatory environment in the metaverse. This first requires ensuring that the data used to construct the metaverse is free of bias or discriminatory elements derived from historical data. However, the real world exhibits biases based on gender, age, race, and other factors, and it is currently considered impossible to satisfy all definitions of fairness simultaneously [57]. If we can satisfy every discriminatory factor by developing classifiers, should we work on that? There is a discussion about whether we should work to remove biases from data or whether we should develop new classifiers that can learn unbiased models [58]. We believe that light should be shed on classifiers such as the AI Fairness 360 (AIF360) which remove bias, and that these devices should be developed with an understanding of bias metrics and mitigation measures by companies.

Furthermore, it is necessary to ensure that the metaverse is accessible and welcoming to people of diverse backgrounds, abilities, and identities. The biggest barrier to using the metaverse is that access to the metaverse is a very high hurdle. There are several possible ways to overcome this hurdle. For example, for those who cannot afford to access, the government establishing free public access points can offer the opportunity to participate in the metaverse. Second, companies need to make the device price lower to make it accessible to a wide range of users. Thirdly, it is also essential for companies to promote multilingual support at the time of use and to take into account regional differences in deployment. It can also facilitate the expansion of users by accommodating different geographies and languages, thereby respecting cultural diversity. Moreover, there is an accessibility problem if the metaverse is only developed for the majority, leaving out specific groups such as older people who are less digital savvy (digital divide) or people with limited sight or hearing [59]. Solutions include designing interfaces (in nature metaverse should be designed free from physical constraints) and interactions that meet the needs of disabled people in the company.

Lastly, users need to be empowered as rational human beings living in the metaverse. We (from government to family) must work together to promote digital citizenship, critical thinking skills, and responsible online behavior. For example, government providing the school resources and educational materials to help users use the metaverse safely, make informed decisions, and protect themselves from potential risks will promote digital literacy and empowerment.

4.3 Economic perspective

We consider how we can approach social issues from an economic perspective, particularly about surveillance capitalism and privacy.

First, for privacy concerns, robust data protection and privacy measures need to be implemented to prevent data leakage, unauthorized use, and exploitation. For example, platformer must respect users’ privacy rights, obtain clear consent for data collection and use from users, and provide transparency on how user data is handled. Furthermore, it is imperative to appropriately penalize companies responsible for issues (it is said that current penalties are not enough, and companies are more likely to take bold actions because the benefits outweigh the penalties).

Addressing the challenges posed by surveillance capitalism necessitates fostering competition among firms and safeguarding the interests of various stakeholders, rather than allowing a few corporations to monopolize profits. A structured approach, for example, where platform operators are proactive and government agencies provide oversight should be established. Concretely, the government can stimulate competition by implementing policies that encourage innovation and create opportunities for new entrants and small firms and platformer to implement, which can reduce oligopolistic behavior. In addition, platformer need to establish principles that ensure content creators, artists, developers, and other contributors receive fair recognition and compensation for their work within the metaverse. For example, platform operators should establish transparent revenue-sharing models and fair payment structures that recognize and reward the value that contributors bring to the virtual environment.

Furthermore, platformer must obtain explicit consent from users regarding surveillance practices. Users should be fully informed about the nature and extent of surveillance. For example, individuals working within the metaverse economic zone might be monitored through various data protocols. This raises significant concerns about employee rights and the ethical limits of surveillance, which must be addressed to protect all parties involved.

In summary, we have introduced ethical design principles for the sustainable metaverse from three different angles. However, these principles are underpinned by the necessity of a robust governance and legal framework. We must create virtual worlds that can thrive and evolve in ways that are beneficial to individuals, society, and the environment in the long term.

5 Conclusion

In this paper we have investigated and analyzed human-computer interactions in the metaverse, where new forms of interaction are emerging due to the development of XR technology and the technologically enabled enhancement of human perception. We have discussed the ethical issues that would arise in the metaverse, including privacy and security, surveillance capitalism, cyber-syndromes, and amplifications of social problems. These issues on the metaverse are fundamentally different in their characteristics from those on the real world and the traditional Internet and may lead to potential threats to the sustainable development and social health of the metaverse. We have finally proposed ethical design principles for the sustainable metaverse from three perspectives (i.e., environmental, social, and economical), including energy efficiency and e-waste management, promotion of social inclusion and diversity, and protection of privacy and security. The proposals provide guidelines to ensure that the development of the metaverse is environmentally sustainable and socially sound. How to implement the ethical design principles in a realistic manner through the coordination of various stakeholders and relevant policies would need to be explored further and thus be our future work.