Adaptive Re-Use of Cultural Heritage Sites: A Strategy for Circular Economy

Abstract

Circular economy (CE) is a recently introduced concept by the EU and several national governments that aims to reduce the total resources extracted from the environment and limit waste generated by human activities to achieve human well-being and sustainability. This review aims to bring awareness of heritage sites’ role and significance in reducing carbon footprints as a strategy for applying CE and promoting sustainable urban development. This study adopts a qualitative content analysis methodology, selecting academic literature, international case studies, and policy documents based on their relevance to CE principles and heritage conservation. The approach examines the emergence and dissemination of these concepts through published literature, including professional standards and guidelines for valuing and managing heritage sites. Key themes include adaptive re-use strategies, preventive conservation, and policy integration. A comparative reflection on international case studies was conducted to highlight trends, regional variations, and challenges. This review concludes by identifying research gaps and proposing future directions, reinforcing the value of heritage sites as pivotal assets in advancing CE frameworks. This structured synthesis provides a theoretical and practical contribution to integrating circular economy strategies in heritage conservation.

1. Introduction

The circular economy is a concept aimed at minimizing resource extraction and environmental impact by extending the useful life of materials and elements through re-use [1,2]. This approach can assist in advancing cities to unlock economic, social, and environmental benefits aligned with the Sustainable Development Goals and climate objectives [3]. The circular economy garners significant attention as a sustainable practice that preserves cultural heritage sites while reducing environmental impact [4,5]. The Ellen MacArthur Foundation, a global leader in circular economy advocacy, provides a framework that aligns with heritage conservation through material efficiency, adaptive re-use, and regenerative urban planning. This framework offers urban policymakers and changemakers a valuable resource for designing a sustainable future that prioritizes environmental protection by reducing carbon footprints. The Foundation’s publications, such as “Building Prosperity” and “Circular Economy in Cities,” emphasize the importance of integrating circularity to foster sustainable built environments [4,6]. The Foundation adopts the principle of adaptive re-use for the lifecycle of cultural heritage sites, prioritizing repurposing existing buildings over demolition or re-building. These principles conserve heritage sites while mitigating carbon emissions and solid waste accumulation. The Circular Economy in Cities framework highlights that integrating circular economy strategies into urban planning can optimize resource efficiency while maintaining the historical value of heritage sites [7].

One area where the principles of circular economy can be embraced is managing cultural heritage sites. Adaptive re-use of cultural heritage sites refers to conserving heritage by providing the site or building with a new function [8,9]. By conserving and managing cultural heritage buildings and sites, the lifespan of these non-renewable resources can be prolonged, contributing to the transition towards a circular economy [8]. Accordingly, this management extends the life cycle of heritage and aligns with the circular economy goal of reducing environmental impacts by re-using resources, which offers a practical alternative to demolition and bypassing wasteful processes associated with new construction [10].

Therefore, this review aims to bring forward awareness of the role of heritage sites and their significance in reducing carbon footprints as a strategy for applying circular economy (CE) and sustainable urban development.

2. Methodological Approach

This review adopted a qualitative content analysis methodology, drawing on academic literature, international case studies, and key policy documents relevant to the circular economy and adaptive re-use of cultural heritage sites [11]. Sources were selected based on their relevance to sustainable urban development, the practical application of CE principles, and geographical diversity. Particular attention was paid to studies that provided measurable impacts or involved recognized frameworks, such as the Adaptive Re-use Potential (ARP) Model. This approach allows for a holistic understanding of how adaptive re-use practices are being implemented globally to support climate objectives and heritage conservation [12].

A structured and transparent process was followed to strengthen this review, drawing on guidance from established content analysis methods [13]. Literature research used Scopus, Web of Science, and Google Scholar to ensure broad academic coverage. The search focused on studies published between 2000 and 2025 and combined keywords such as “circular economy,” “cultural heritage,” “adaptive re-use,” “heritage conservation,” “urban sustainability,” and “built environment.” Boolean operators (AND/OR) helped refine and focus the search results. We included studies that directly addressed CE principles in cultural heritage management, offered practical frameworks or case studies, or discussed the sustainability impacts of adaptive re-use [14]. The researchers excluded sources not specific to cultural heritage or lacking methodological clarity. Case studies were selected to reflect geographic diversity (Europe, Australia, Japan) and different site typologies (industrial, religious, civic). In addition to academic works, key policy documents—such as EU circular economy action plans and UNESCO charters—were reviewed to provide a policy context and real-world examples [1]. It is important to note that, as this is not a systematic review but rather a qualitative narrative synthesis, no formal PRISMA flow diagram or numerical accounting of included and excluded studies was produced [15]. Instead, this review aimed to capture various perspectives, practices, and challenges, offering valuable insights for researchers and practitioners.

3. Thematic Literature Review

3.1. About Circular Economy (CE) and Its Relation to the Sustainability Concept

Continuous human activities resulted in environmental degradation, destruction of habitats, and alterations to ecosystems that threaten human well-being, which urged us to engage in more sustainable strategies, such as the Circular Economy (CE) [16,17]. Circular economy (CE) is a recently introduced concept by the EU and several national governments, such as China, Japan, the UK, France, Canada, the Netherlands, Sweden, Finland, and several businesses worldwide [18,19].

In economics, a product supply chain is considered a linear chain that transforms natural resources into products that support human well-being. Then, these products are used by the consumers and disposed of as waste [20]. On the contrary, the CE supply model is an alternative cyclical flow model to the linear one [19]. Unlike the linear flow model, the CE approach emphasizes product, component, and material re-use, renovation, remanufacturing and repair, flowing and upgrading, and solar, wind, biomass, and waste-derived energy utilization throughout the product value chain cradle-to-cradle life cycle [19,21,22]. “Cradle to cradle” can be defined as “the design and production of products of all types in such a way that at the end of their life, they can be truly recycled (upcycled), imitating nature’s cycle with everything either recycled or returned to the earth, directly or indirectly through food, as a completely safe, nontoxic, and biodegradable nutrient” [12].

Despite that, practitioners, i.e., policymakers, businesses, business consultants, business associations, business foundations, etc., have almost entirely developed the CE concept and practice. The scientific research content of CE remains almost unexplored [17]. Accordingly, there is no specific definition for CE; many are decided according to the different theoretical stimulations [23,24].

One of these definitions that fits well with the context of this research is Gillian Foster’s 2020 definition of CE as “the production and consumption processes that require the minimum overall natural resource extraction and environmental impact by extending the use of materials and reducing the consumption and waste of materials and energy.” [7]. CE aims to extend the useful life of materials by transforming them into new products, designing for longevity, minimizing waste, re-using materials, and redefining resource consumption to include sharing and services supply instead of individual ownership. In addition, CE stresses using non-toxic, renewable, and biodegradable materials with the lowest possible lifecycle impacts, and this reflects its importance and the role it can play as a sustainability concept [25].

3.2. The Environmental Impact of Buildings

Shelters have always been an urgent need for human well-being, which has caused the successive manufacture, use, and disposal of buildings for sheltering on a massive scale, resulting in significant consumption of the environment’s natural resources and increasing the waste returned to it. Accordingly, the construction industry was the largest consumer of resources and raw materials globally [26]. In addition, the greenhouse gas emissions caused by the building industry and the effects of global climate change have risen steadily. In 2017, the International Energy Agency noted a 45% increase in building-related emissions since 1990 [7]. Numerous studies indicate that some procedures can cost-effectively reduce buildings’ energy usage by 20–50% [25]. Therefore, managing the environmental impacts of buildings, specifically greenhouse gas emissions, is critical to limiting global warming and achieving a sustainable economy [7].

The importance of energy efficiency policies was first introduced during the oil crisis of the 1970s. In recent years, it has gained full attention from different governments. The global financial crisis has recently led to different measures focusing on efficiently reducing the buildings’ energy consumption and emissions. The International Panel on Climate Change (IPCC) in October 2018 assessed options to limit global warming to 1.5 °C above the pre-industrial levels and mentioned that the building sector should rapidly change to meet this goal [27].

Previous research showed that the existing buildings are the source of 24% of the global carbon dioxide emissions and 40% of the world’s total primary energy consumption [28]. Accordingly, it is essential to re-think the existing potential of sustainable management solutions such as heritage building stock retrofitting projects [29].

3.3. Sites of Cultural Heritage (Economic Value, Management, and Opportunities in Today’s Cities)

The United Nations Educational, Scientific and Cultural Organization (UNESCO) defined cultural heritage as “artifacts, monuments, a group of buildings and sites, museums that have a diversity of values including symbolic, historic, artistic, aesthetic, ethnological or anthropological, scientific, and social significance,” and it considered it as “our legacy from the past, what we live with today, and what we pass on to future generations” [30].

As well as the International Council on Monuments and Sites (ICOMOS), 2022 defined cultural heritage as “an expression of the ways of living developed by a community and passed on from generation to generation, including customs, practices, places, objects, artistic expression, and values.” [31]. Feather (2006) defined it as “a human creation intended to inform” [32]. In Australia, the legislation of the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act) [33] expanded the definition of a place of heritage value as a “place’s natural and cultural environment having esthetic, historic, scientific, or social significance or other significance for current and future generations of Australians” [33].

Accordingly, cultural heritage assets can be seen as cultural resources that must be protected to the same extent as other non-renewable resources. They possess the stewardship quality, which attempts to maximally prolong the building’s usable life by recycling and other means as required. Moreover, cultural heritage has several social and economic benefits, such as building social capital through education, providing society with social cohesion and identity, and creating a sense of place. Economically, promoting heritage tourism and benefiting the community positively [34]. Heritage buildings embody energy from their age and valuable materials, as they have been built with superior craftsmanship, supporting a long physical life. Furthermore, they possess a practical design for passive heating, lighting, ventilation, and well-site positioning [4]. Therefore, heritage buildings could be considered a resource factor in the urban ecosystem that should not be separated from the artificial or natural context in which they occur [35].

3.4. Heritage Sites as Catalysts for Change

Heritage sites go beyond mere remnants of history; they function as vibrant symbols of cultural identity and provide a unique opportunity to promote sustainable practices. Preserving these sites encourages repurposing and advocates for the adaptive re-use of existing structures, thereby lessening the demand for resource-intensive new constructions [36]. This strategic approach perfectly aligns with the circular economy ideology’s principles, emphasizing responsible material utilization to reduce waste. Heritage sites, through adaptive re-use, can play an integral role in the shift toward a low-carbon society [37]. This aligns with the principles outlined in the Faro Convention (Council of Europe Framework Convention on the Value of Cultural Heritage for Society), which emphasizes the cultural heritage’s value as a resource for human development, social cohesion, and sustainability [38].

Heritage sites possess considerable cultural and historical significance, acting as dynamic reflections of a society’s identity. Beyond safeguarding the past, these sites present a chance to champion sustainable practices and contribute to the principles of the circular economy [39]. Repurposing existing structures instead of building new ones conserves resources and minimizes the waste associated with conventional demolition methods. These sites can showcase sustainable technology by incorporating renewable energy systems, such as solar panels or geothermal heating, into heritage buildings [40].

In adherence to the principles ingrained in the circular economy ideology, adaptive re-use ensures the responsible utilization of materials and resources. This approach diminishes the need for resource-intensive construction, promoting efficient utilization that mitigates environmental impact. Moreover, heritage sites can be catalysts in pursuing a low-carbon society by actively engaging in the transition towards sustainability through adaptive re-use strategies [41].

Managing Cultural Heritage Sites for a Net-Zero Carbon Target

Aplin (2002) [42] extracted various general heritage conservation and management principles from the Burra Charter. For example, he defined conservation as “all the processes of looking after a place to retain its cultural significance […] including maintenance and may according to circumstances include preservation, restoration, reconstruction, and adaptation […] commonly a combination of more than one of these” [42].

Sevcenko (1983) explained the importance of conservation by mentioning that it is a step toward development because it is not limited to maintaining the forms of historical buildings for posterity [43]. However, it is also the mechanism for carrying over the old traditions from the conceptual and the functional viewpoints [43]. Accordingly, conservation can be understood as maintaining the presence of the past in the present, and this involves all the processes of preservation, restoration, adaptive re-use of old buildings, and regeneration [43].

In the 1960s, the urban conservation concept was introduced and focused on managing the change in historic cities; it aimed to blend existing and new developments and maintain the character of historic quarters while serving their communities and new needs. Urban conservation fulfilled the political, economic, and social concerns by protecting cultural continuity and adapting gradually to the urban environment [44].

Since conservation is an inclusive concept that captures, e.g., protection, preservation, gentrification, renewal, and adaptive use, it is essential to define these terms in the following [45,46]:

• Regeneration: combines building re-use, urban design, and new build projects within an economic development framework.
• Adaptive re-use/Adaptation: making changes to a building to accommodate a new use is often a means of enabling the continued usefulness of a historic building, considering that the new use integrates with the original fabric.
• Protection: putting legal, physical, or other tangible measures in place to safeguard cultural property from damage, like placing a historic building or site on a statutory list.
• Reconstitution: re-building a collapsed building or parts of it piece by piece and must be based on solid evidence
• Reconstruction: returning a place to a known earlier state, and it is distinguished from restoration by introducing new material into the original fabric.
• Preservation: maintaining the fabric of a place in its existing state and hindering deterioration.
• Restoration: returning the existing fabric of a place to a known earlier state by removing accretions or reassembling existing components without introducing new materials.

The question that emerges here is whether sustainability through retrofitting works with conservation. The balance between human comfort, heritage conservation, and cost-effective energy technologies is the challenge that needs to be addressed here [47].

Rodwell (2007) defined sustainability as “the means to provide a safe, healthy, and comfortable indoor environment while limiting the impact on the earth’s natural resources.” He also asserts that minimum intervention is a principle both conservation and sustainability share [44]. Further, he pointed out that reducing, recycling, and re-using non-renewable resources and waste management are the central conjunction between conservation and sustainability [44]. Orbasli (2008) illustrated that the sustainability of built heritage should carry the city’s character and contribute to its economy [45]. The collaboration between sustainable retrofitting and the conservation of heritage buildings is significant as it saves the cultural and social characteristics linked to society’s identity and increases the energy efficiency of the building, which maximizes the society’s and environmental gain [48]. Conservation principles are also aligned with sustainability theories to contribute to the building re-use of an urban area by keeping its cultural and material heritage. Hence, building conservation and energy efficiency are critical aspects of sustainability [49].

According to the ICOMOS New Zealand Charter, “conservation should involve the least degree of intervention consistent with long-term care”. The lower the degree of intervention in historic buildings, the better in sustainability, as it lowers costs concerning materials, transport, energy, and pollution compared to erecting new buildings [34]. Therefore, it is usually better to take the most conservative approach, like preventing deterioration instead of more drastic interventions like reconstruction in heritage building conservation, especially regarding sustainable values like embodied energy and cultural and historical significance [50]. The degree to which the original structure would be changed determines this preference. According to E. Okba and M. Embaby’s explanation (2013), to achieve optimal sustainability to improve the building’s environmental and economic sustainability, more sustainable treatments such as energy and resource efficiency techniques and renewable energy technologies should be incorporated [49].

These intervention techniques of re-use can only be performed in more conservative intervention strategies (e.g., prevention of deterioration, preservation, consolidation, and restoration). At the same time, invasive alterations are not allowed. Furthermore, the invasive conservation intervention strategies (e.g., reproduction and reconstruction) deal with the historic and symbolic values of the building and not necessarily its functional value (as the building should be partially or wholly lost). Hence, the re-use approach should be suitable for introducing sustainability and allowing the building to meet current green architecture standards [29].

3.5. Adaptive Re-Use and Sustainability

Rodrigues and Freire (2017) defined adaptive re-use as “the retrofitting of old buildings for new uses” [51]. This is feasible instead of replacing them with replacements to reduce climate change and global warming [51]. They also agreed with Bullen and Love (2011) that acquiring adaptive re-use considering the building’s lifecycle (LC) perspective can remarkably reduce the whole building’s LC waste and cost and enhance its functionality [52]. Previous literature indicates that the main driver for environmental benefits is “embodied energy,” as the initial cumulative input energy required to construct the building [53]. Alternatively, Cabeza et al. (2013) illustrated the operational energy consumed while using the building [54]. Embodied energy is calculated as the amount of carbon dioxide circumvented by re-use or the amount of carbon dioxide equivalent to the energy and materials used to construct the existing building, taking advantage of the building’s longevity. However, re-using existing buildings may not reduce the need or desire to construct new buildings. For example, the spillover effects (referring to the impact that seemingly unrelated events in one nation can have on the economies of other nations [45]) may result in more buildings being built overall [55]. Second, adaptively re-used heritage buildings, such as zero-emission buildings, could fall short of today’s expected standards [56]. Moreover, circular and adaptive re-use strategies can be more expensive than demolition and new construction, regardless of the environmental and sustainability benefits [57]. Nevertheless, despite these limitations, the literature supports the adaptive re-use of heritage buildings as a win for the environment [7].

For example, the United Nations Environment Programme (UNEP) mentioned that adaptive re-use and retrofitting play a crucial role in reducing emissions within the built environment, pointing to the importance of focusing on adapting and retrofitting existing buildings to the optimal energy efficiency standard by the building sector [58,59]. Moreover, Gorse (2009) [60] declared that building recycling is the best example of practical environmental benefits in sustainability. Added to re-using the assemblies and materials retrieved from the building that are adaptively re-used [60].

3.6. Adaptive Re-Use Potential (ARP) Model

The Adaptive Re-use Potential (ARP) Model is a comprehensive framework designed to assess the potential for adaptive re-use projects in the built environment [61]. It offers a dynamic approach to understanding a building’s life cycle, irrespective of its physical appearance or obsolescence. The ARP Model (see Figure 1) allows for calculating a building’s adaptive re-use potential at any time, enabling stakeholders to decide when to intervene in the building’s life cycle [62].

The ARP Model diagram in Figure 1 shows how a building’s potential for adaptive re-use changes over its effective life [63,64]. The x-axis represents the building’s age in years (0 to 100), and the y-axis indicates the ARP score as a percentage (0% to 100%). A decay curve illustrates the natural drop in ARP as the building ages, following the equation y = 100 − x²/100. Key points on the diagram include the Effective Building Age (ELb), which marks the building’s current age; the Effective Useful Life (ELu), representing the age at which the building’s re-use potential is at its highest; and the Effective Physical Life (ELp), marking the end of the building’s usable lifespan. The diagram is split into zones: an increasing potential zone (from new construction up to ELu) where ARP rises as the building matures and gains heritage value, and a decreasing potential zone (after ELu) where ARP falls due to deterioration and obsolescence. Future aging is also shown, with projected declines in ARP without intervention. Two formulas in the diagram calculate ARP during these phases: one for the increasing potential stage and another for the decreasing stage. These formulas help with making strategic decisions about when to intervene. This model provides helpful guidance for balancing heritage conservation, material efficiency, and sustainability within the circular economy framework [63,64].

One of the key advantages of the ARP Model is its applicability to a wide range of building typologies and geographic locations. While the model was initially demonstrated through a case study in Hong Kong, it has proven to have generic applications that extend beyond national borders [65]. This versatility makes it a valuable tool for decision-makers, urban planners, and architects worldwide seeking to explore the potential of adaptive re-use in various contexts [66].

The ARP Model’s utility and robustness have been established through extensive research and practical application. Langston (2008) reported that the model has been tested globally in 64 adaptive re-use projects [67]. This extensive validation process has solidified the ARP Model as a credible and reliable tool for evaluating adaptive re-use potential [68]. Furthermore, as Langston (2010) described, the model’s efficacy has been reaffirmed by integrating with a multi-criteria decision analysis tool called iconCUR [69,70].

One of the central functions of the ARP Model is to assist building owners or prospective developers in strategically allocating capital during a building’s life cycle [71]. By identifying critical junctures in a building’s life, the model can inform decision-makers about the ideal timing for intervention. This strategic investment preserves the building’s adaptive re-use potential and resets the decay curve, potentially extending the building’s useful functional life [72].

The ARP Model introduces a scoring system to quantify a building’s adaptive re-use potential. A score above 50% indicates a high potential for adaptive re-use, while scores between 20% and 50% signify a moderate level of potential. Scores below 20% indicate a poor value, suggesting that adaptive re-use may not be viable [63]. This scoring system is a valuable metric for gauging a building’s potential and guiding decisions regarding its future [73].

One of the most critical contributions of the ARP Model is its alignment with the circular economy principles. In the circular economy context, the model’s emphasis on material and resource efficiency is paramount. Adaptive re-use inherently promotes efficiently utilizing existing building materials, infrastructure, and resources [14,56]. This approach minimizes the demand for new resource extraction and reduces waste generation, thereby contributing to the circular economy’s goal of preserving and extending the life of resources within the system [74].

Additionally, the ARP Model helps reduce waste generated during construction and demolition processes. Circular economy principles prioritize the elimination of waste or, at the very least, converting waste into valuable inputs for other processes. Mrad and Ribeiro (2022) mentioned that by encouraging the refurbishment of existing structures, the ARP Model significantly minimizes waste disposal requirements, aligning with the circular economy’s aim to eliminate waste in the built environment [1].

Preserving embodied energy is another vital aspect of the ARP Model’s contribution to the circular economy. The model recognizes the energy invested in the extraction, manufacturing, and transportation of construction materials, commonly known as embodied energy [75]. By re-using these materials within the building, the ARP Model helps conserve this embodied energy, reducing the environmental impact of new construction and enhancing the circular economy’s resource efficiency [76].

Furthermore, the ARP Model supports life cycle assessment (LCA) as a tool for evaluating the environmental performance of adaptive re-use projects. LCA is an essential part of the circular economy approach, as it considers all phases of a building’s life cycle, from construction to operation and eventual deconstruction [77]. By incorporating LCA into its methodology, the ARP Model ensures that environmental considerations are central to the decision-making process, in line with circular economy principles [78].

The APR model has been successfully applied in several European Union countries. The CLIC Project (Circular Economy-based Adaptive Re-use of Cultural Heritage) explores the role of the circular economy in the adaptive re-use of cultural heritage buildings across Europe [14]. Through various case studies, the project highlights the importance of adaptive re-use in preserving cultural heritage sites while promoting economic growth and environmental sustainability. For example, the project in the Netherlands is the Linnaeusborg Building, an industrial facility repurposed as a state-of-the-art life sciences research center at the University of Groningen. The ARP Model at the site integrated modern research facilities while ensuring energy efficiency, sustainable design, and the preservation of building structures without compromising the site’s historical character [79].

Additionally, the project adopted the principles of the circular economy (CE) by re-using materials, reducing waste, and ensuring the long-term adaptation of the building. A key aspect of the project was stakeholder engagement, which played a crucial role in the success of adaptive re-use. Collaboration between governments, academia, and private investors was essential to ensuring effective financial planning and project execution [79].

Another example can be seen in the Queensland Brewery in Australia, where the site was transformed from an industrial facility into a mixed-use development featuring residential, office, and retail spaces. Due to the site’s strategic location and structure, the ARP Model successfully predicted its potential for re-use [80]. Furthermore, the project’s outcomes aligned with the ARP Model’s assessment, demonstrating its high effectiveness in guiding decision-making and helping stakeholders prioritize projects based on social impact, sustainability, economic benefits, and the potential for adaptive re-use [80].

Likewise, another successful case study was found in Milan, Italy. Originally established in 1910, the site was transformed from a former gin distillery into a contemporary art and cultural complex. The project was repurposed under the direction of OMA (Office for Metropolitan Architecture), led by Rem Koolhaas, and was completed in 2015. This project preserved the site’s historical value while introducing modern additions, such as the remarkable gold-leaf-covered Torre, which provides new exhibition spaces [81].

Accordingly, the adaptive re-use potential (ARP) Model could be a powerful tool for integrating circular economy principles into the built environment. It offers a dynamic approach to assessing a building’s potential for adaptive re-use and provides decision-makers with a structured framework for strategic intervention during its life cycle. The ARP Model’s ability to align with the circular economy by promoting material and resource efficiency, reducing waste, preserving embodied energy, and emphasizing life cycle assessment makes it valuable in pursuing a more sustainable and resource-efficient built environment.

In addition to adaptive re-use, preventive conservation is a complementary strategy that reinforces circular economy principles [38]. Preventive conservation emphasizes routine maintenance, environmental control, and early intervention to extend the usable life of heritage buildings rather than depending on extensive restoration efforts after degradation has occurred [82]. Material conservation, waste reduction, and embodied energy maintenance—all fundamental goals of CE—are achieved by minimizing physical deterioration, which lessens the need for resource-intensive repairs or replacements. Since preventive conservation promotes the continuation of use and function without causing intrusive changes, acknowledging its significance within the framework of this review advances our knowledge of sustainable heritage management [83]. It offers a fundamental layer that enables the more efficient and sustainable application of adaptive re-use techniques [84].

4. Critical Analysis and Discussion

Circular economy (CE) is a concept that has gained prominence globally as governments and organizations strive to reduce environmental impact and promote sustainability. Several international examples illustrate the application of CE principles, often focusing on heritage sites and urban development [14]. The following are some relevant examples:

The European Union has played a significant role in championing circular economy practices, mainly through the introduction of legislation and initiatives aimed at reducing resource extraction and waste generation. Regarding heritage sites, EU member countries have implemented restoration and conservation projects prioritizing sustainable materials and techniques [85]. An example of this can be seen in Rome, where the restoration of historic buildings often prioritizes using reclaimed materials as an alternative to sourcing new resources [86]. The Netherlands is known for its innovative circular economy practices. For instance, the De Ceuvel project in Amsterdam is considered a pioneering example of regenerative design combining innovative materials to simulate the circular economic approach by transforming the derelict industrial site into a sustainable urban area. The site was a contaminated shipyard, so the project promotes adaptive re-use, smart materials, and phytoremediation (phytoremediation is defined as a bioremediation technique that uses plants and soil microbes to reduce hazardous contaminants in the environment, particularly heavy metals, by absorbing and fixing them in plant tissues [87]) that reduce the carbon footprint while conserving the industrial heritage site [88]. The regeneration design of De Ceuvel focused on repurposing the existing structures of the site and transforming houseboats into innovative and creative communities and workspaces [89]. Pomponi and Moncaster (2017) stated that the adaptive re-use approach supports the principles of circular economy (CE) and environmental sustainability by avoiding the carbon dioxide emissions emitted from demolition and new construction [90]. Additionally, it conserves the cultural and industrial heritage sites from destruction [14,91].

Additionally, smart materials must be sustainable to protect the environment and align with the purpose of the circular economy (CE). Bio-based and recycled materials such as timber and hempcrete can contribute to carbon sequestration and were used in the renovation at De Ceuvel to guarantee smart insulation. Moreover, recycled wood and steel from the old shipyard minimized the extraction of new resources, which minimizes carbon dioxide emissions [92] for soil recovery in the heavily contaminated site. Phytoremediation is used to clean the soil with willow and sunflower plants that absorb toxins like heavy metals. This approach relies on low-carbon remediation, allows the land to regenerate naturally, and eliminates the need for chemical treatments, supporting the Circular Economy (CE) principles [93]. Moreover, energy efficiency is significant in smart design to make the heritage site more sustainable. In the De Ceuvel project, high-performance insulation, renewable energy technologies, and innovative wastewater treatment systems were applied and integrated. To illustrate, the site’s environmental effect was lessened by applying bio-filtration systems that reclaimed greywater for future use and solar panels and heat recovery systems that provided sustainable (clean) energy [94].

Furthermore, Japan has a rich cultural heritage, and they have incorporated circular economy principles into heritage site management. Kyoto, known for its historic temples and shrines, has implemented sustainable tourism practices [95]. This includes encouraging visitors to use public transportation, reducing waste through effective recycling programs, and promoting local and sustainable products in souvenir shops around heritage sites. A circular economy strategy holds great potential for the adaptive re-use of cultural heritage sites for carbon footprint reduction. Despite its limited land area, Singapore has made significant strides in sustainable urban development [96]. They have integrated heritage conservation into urban planning, such as restoring Chinatown’s historic shophouses. These renovations often involve using environmentally friendly materials and technologies, showcasing the compatibility of heritage preservation and sustainability [97].

With its vast cultural heritage, India has also embraced circular economy principles. The restoration of historical monuments like the Taj Mahal includes sustainable practices, such as using traditional construction techniques and locally sourced materials [98]. Some heritage cities, like Jaipur, have also implemented waste reduction and recycling programs in and around heritage sites [99].

Overall, the adaptive re-use of cultural heritage sites for carbon footprint reduction is a strategy that aligns with the CE concept. In all of these examples, heritage sites play a crucial role in demonstrating the compatibility of heritage preservation with circular economy principles and sustainable urban development [7]. These initiatives not only reduce carbon footprints but also showcase the importance of cultural heritage in promoting sustainability and enhancing the overall well-being of communities. They serve as models for other regions and countries looking to integrate circular economy principles into heritage site management [100]. To provide a clearer comparative perspective on these international examples,

Table 1. Summary of key case studies on adaptive re-use in a CE context. Source: F.H. based on [86,88,90,93,95,97,99,100].

Country	Site	Typology	CE Strategy	Outcome	Challenges
Netherlands	De Ceuvel	Industrial	Phytoremediation, material re-use, and energy efficiency	Low-carbon remediation and creative community re-use	Soil contamination
Italy	Fondazione Prada	Industrial/Cultural	Modern addition + heritage preservation	Cultural branding, tourism revitalization	Balancing modern and historic elements
Australia	Queensland Brewery	Industrial	Mixed-use redevelopment	Urban renewal and resource efficiency	Economic cost of adaptation
Japan	Kyoto temples	Religious	Sustainable tourism, maintenance	Reduced waste and cultural preservation	Visitor impact management
Singapore	Chinatown shophouses	Civic/Commercial	Restoration with eco-materials	Heritage preservation and urban sustainability	High-density constraints
India	Taj Mahal and Jaipur	Monumental/Urban	Traditional techniques, local materials, and waste reduction	Cultural preservation and reduced environmental impact	Scale and complexity

summarizes key characteristics of the cases, including their circular economy strategies, outcomes, and challenges.

Rather than a simple description, this section provides a comparative reflection on these adaptive re-use examples within the circular economy (CE) context. As summarized in Table 1, while all cases contribute to extending material life and reducing resource extraction, they vary in strategy and emphasis. For example, De Ceuvel focuses on environmental remediation and community re-use, whereas Fondazione Prada (Italy) highlights cultural branding through architectural addition. Kyoto prioritizes soft interventions like tourism management, while Queensland Brewery (Australia) demonstrates urban regeneration through structural adaptation. Challenges also differ in the following ways: De Ceuvel contends with soil contamination; Fondazione Prada balances preservation and innovation; Queensland Brewery with economic costs; and Kyoto with visitor management. These cases expose gaps in the consistent application of lifecycle carbon assessments and CE policy frameworks, and they underline the need for standardized metrics to evaluate CE success in heritage re-use. Future work should explore comparative policy analysis, lifecycle carbon accounting, and the development of CE assessment frameworks for heritage sites.

To summarize these connections and gaps visually, Figure 2 presents a conceptual diagram highlighting trends, challenges, and future directions for adaptive re-use within the circular economy framework.

5. Conclusions

The concept of a circular economy (CE) has emerged as a powerful tool in the global effort to reduce resource extraction, minimize waste, and promote sustainability. This review has highlighted the significant role of heritage sites in applying CE principles for sustainable urban development.

Heritage sites, often considered remnants of the past, have the potential to become catalysts for change in the pursuit of a low-carbon society. By prioritizing adaptive re-use over demolition and new construction, these sites can actively contribute to reducing carbon footprints associated with the building industry. Moreover, heritage conservation principles align closely with sustainability objectives. The emphasis on minimal intervention and the preservation of existing materials respects these sites’ cultural and historical value and promotes sustainability by reducing the need for new resource-intensive construction.

Several international examples have showcased the successful integration of CE principles into heritage site management. From Rome’s use of reclaimed materials in restoration to Amsterdam’s low-carbon retrofitting projects, these cases demonstrate the compatibility of heritage preservation with sustainability goals. Heritage sites hold immense potential for achieving sustainable urban development and reducing carbon footprints.

This study contributes methodologically by applying a structured qualitative content analysis to synthesize academic literature, international case studies, and policy frameworks. This approach ensures a holistic understanding of the intersection between CE and heritage management and offers a practical framework for urban planning decision-making. The findings provide a foundation for planners and policymakers to develop adaptive re-use strategies that support carbon reduction goals while preserving cultural heritage.

However, this study’s broad international scope may constrain the depth of analysis for each regional context. Future research could better understand the advantages and limitations of a given setting with a more focused geographic focus or comparative regional studies. Additionally, integrating lifecycle assessment tools and carbon accounting models into adaptive re-use evaluation frameworks presents a promising direction for further investigation. Overall, this review highlights the value of heritage sites as cultural assets and active contributors to sustainable urban development when managed through a circular economy lens.