Circular Economy in the Built Environment

Circular Economy in the Built Environment

Here is a review of almost all spatial characteristics influencing the circular economy in today’s built environment.

A review of spatial characteristics influencing circular economy in the built environment

By Ning Zhang, Karin Gruhler & Georg Schiller


Industrialization, population growth, and urbanization are all trends driving the explosive growth of the construction industry. Creating buildings to house people and operate industry, together with building infrastructure to provide public services, requires prodigious quantities of energy and materials. Most of these virgin materials are non-renewable, and resource shortages caused by the development of the built environment are becoming increasingly inevitable. The gradually evolved circular economy (CE) is considered a way to ease the depletion of resources by extending service life, increasing efficiency, and converting waste into resources. However, the circularity of construction materials shows heavy regional distinctness due to the difference in spatial contexts in the geographical sense, resulting in the same CE business models (CEBMs) not being adapted to all regions. To optimize resource loops and formulate effective CEBMs, it is essential to understand the relationship between space and CE in the built environment. This paper reviews existing publications to summarize the research trends, examine how spatial features are reflected in the circularity of materials, and identify connections between spatial and CE clues. We found that the majority of contributors in this interdisciplinary field are from countries with middle to high levels of urbanization. Further, the case analysis details the material dynamics in different spatial contexts and links space and material cycles. The results indicate that the spatial characteristics can indeed influence the circularity of materials through varying resource cycling patterns. By utilizing spatial information wisely can help design locally adapted CEBMs and maximize the value chain of construction materials.


Significant demand for natural resources has arisen with the massive expansion of the cities and the rising population worldwide. The development of the built environment is the largest consumer of resources, consuming approximately 35–45% of materials and contributing 40% of global GHG emissions associated with material use (Hertwich et al. 2020; Mhatre et al. 2021). The ensuing resource exploration and related environmental impacts have intensified. It is estimated that the global consumption of building materials has tripled from 2000 to 2017 and produced 30–40% of the world’s solid waste and nearly 5 Gt CO2 emissions, or 10% of global annual emissions (EMF 2015; Pomponi and Moncaster 2017; Hertwich et al. 2020; López Ruiz et al. 2020; Huang et al. 2020).

The built environment is the physical surroundings created by humans for activities, ranging from personal places to large-scale urban settlements that often include buildings, cultural landscapes, and their supporting infrastructure (Moffatt and Kohler 2008; Hollnagel 2014). Opoku (2015) points out that the built environment is not only the physical environment but also the interaction of people in the local community and their cultural experiences. The physical constituents of which differ significantly from other products in that they are characterized by long lifetimes, numerous stakeholders, and hundreds of components and ancillary materials interacting dynamically in the spatial and temporal dimensions (Hart et al. 2019). The inherent complexity within the built environment is seen as a challenge for sustainable urban transition (Pomponi and Moncaster 2017).

Circular economy (CE) is one of the essential conditions and solutions for fostering and promoting sustainability (Geissdoerfer et al. 2017). The CE is an economic or industrial concept that distinguishes itself from the traditional linear economy of unsustainability. It is often understood as a restorative and regenerative economic model that includes three types of business models (CE business models/CEBMs): (1) those that increase resource efficiency and reduce resource consumption (narrowing); (2) those that promote reuse and extended service life through repair, remanufacture, upgrades and retrofits (slowing); and (3) those that convert waste into resources by recycling materials (closing) (Stahel 2016; Kirchherr et al. 2017; Figge et al. 2018; Geisendorf and Pietrulla 2018; Gallego-Schmid et al. 2020). It is also well known that urban systems often exhibit linear material flows and inefficient use of resources (Huang and Hsu 2003). Turning linear practices into circularity and maximizing the utility and value of resources is becoming a new model for production and consumption to protect the environment, mitigate climate change, and conserve resources (Cheshire 2019; Harris et al. 2021; Zeng et al. 2022). But incorrect policy formulation and thoughtless pursuit of CE strategies can negatively affect (Corvellec et al. 2021). Many voices currently argue that CE lacks any actual consensus on the magnitude of the economic, social, and environmental “win–win-win” benefits (Aguilar-Hernandez et al. 2021) and even leads to more significant environmental impacts, economic unsuccess, and employment losses (Spoerri et al. 2009; Schröder et al. 2020; Blum et al. 2020).

Circularity in the built environment refers to an approximation in terms of the materiality of immobile elements of the built environment, such as buildings and infrastructures, and their dynamics. These elements are predominantly composed of bulk building materials, mainly non-metallic mineral materials (Schiller et al. 2017b; Gontia et al. 2018; Yang et al. 2020). Despite few products are manufactured, purchased, disposed of, and recycled in the same geographic location in today’s global market (Skene 2018), the transportation distances of these bulk building materials are limited compared to other types of products due to their low specific value-added (Schiller et al. 2017a). Therefore, Schiller et al. (2017a) point out that analyses on (also circular) material flow in the built environment should be applied regionally, which also applies to studies of the availability and security of the supply of natural raw materials in the built environment (Schiller et al. 2020). It can be concluded that the regional context or the spatial context in the geographical sense (Scholl et al. 1996), in which the built environment is integrated, has a decisive influence on material flows in general and their circularity in particular.

Space is a central concept in geography that broadly consists of two distinctive interpretations: a fundamental attribute of reality (often used with time) and a counting term that denotes human conceptual constructs borne of individual experience and societal factors (Newell and Cousins 2015; Grossner 2017). Spatiality and space are two frequently confused concepts. In contrast to space, spatiality is spatial practices rather than an exogenously given and absolute coordinate system that refers to the ongoing processes and imaginations of making space/materials, regulating behaviors, and creating experiences (Mayhew 2015; Kobayashi 2017). Space is a more relevant core term than spatiality in discussing the built environment in the physical sense rather than the formation process. The importance of space in the circularity of the built environment has been implicitly mentioned in many studies on spatial structure and land use planning (Remøy et al. 2019; Lanau and Liu 2020; Gallego-Schmid et al. 2020). Additional studies have also provided fragmented evidence on characteristics of spatial distribution patterns in the built environment that impact the circular flow of materials (e.g., residential and housing density) (Condeixa et al. 2017).

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Call for applications to finance projects in 7 Mediterranean countries

Call for applications to finance projects in 7 Mediterranean countries

Call for applications to finance projects in 7 Mediterranean countries


Green Economy: UfM launches call for applications to finance projects in 7 Mediterranean countries

The above image is of UfM

Call for applications to finance projects in 7 Mediterranean countries

(TAP) – On 16/03/2023, TUNIS/Tunisia. The Union for the Mediterranean (UfM) launched a call for applications to finance projects aimed at promoting employment and entrepreneurship in the green economy sector. The aim is to support the environmental transition of the economies of 7 Mediterranean countries, including Tunisia.


According to information published Thursday by the UfM, this call for applications is intended for NGOs working to support vulnerable populations disproportionately affected by the consequences of climate change and by the evolution of the socio-economic context.


Eligible for this call for applications are non-profit NGOs active in the field of environmental transition of economies in an inclusive manner and with respect for social justice. These NGOs must be based in Algeria, Egypt, Jordan, Lebanon, Morocco, Mauritania, Palestine or Tunisia, with priority given to regional projects. The deadline for applications is May 29, 2023.


The selected candidates will benefit from financial support ranging from 150,000 to 300,000 euros (which represents a sum varying between 500,000 and 1 million dinars) per project, as well as from the UfM’s technical expertise, which will give them greater visibility.


Funded by the UfM with the support of the German Development Cooperation (GIZ), on behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ) and the Spanish Agency for International Development Cooperation (AECID), this initiative, in its first edition, launched in 2020, helped 18,000 people, mainly young people and women, from seven UfM member states (Greece, Italy, Jordan, Lebanon, Malta, Morocco and Tunisia).

These projects address employment challenges in the areas of entrepreneurship, women’s empowerment, sustainable tourism, and education and research.

The green economy, as well as “green” jobs, are set to play a key role in the sustainable recovery of the Mediterranean region from the COVID-19 pandemic.


Sustainable Cities and their Digital Twins

Sustainable Cities and their Digital Twins

There is more and more belief that the key to sustainable cities may lie in increasingly sophisticated digital twins. Let us see what Anthropocene has published.


The key to sustainable cities may lie in increasingly sophisticated digital twins

Researchers offer the first rigorous analysis “In silico” equivalents of urban areas as a powerful tool for sustainable development
March 14, 2023

Dynamic computer models of cities known as ‘digital twins’ could help drive sustainable development across the world’s urban areas, an international team of authors argues in the journal Nature Sustainability.

Digital twins are more than just static models. They incorporate near-real-time data from sensors and other sources to produce “virtual replicas,” the authors explain—“in silico equivalents of real-world objects.”

The concept of digital twins first arose in manufacturing, and they are primarily used in product and process engineering. But the models have also been employed in fields ranging from personalized medicine to climate forecasting, at scales from the molecular to the planetary.

Many researchers have posited that digital twins will be a powerful tool for sustainability efforts. But nobody has taken a rigorous look at the benefits and pitfalls of urban digital twins. The new study takes on that task, paying particular attention to the potential for the modeling approach to help achieve the UN Sustainable Development Goals.

Digital twins have a variety of potential benefits in this realm, the researchers say. They can help cities allocate resources more efficiently—design more effective water grids, predict traffic congestion to guide transportation planning, simulate consumer behavior to recommend energy-saving measures, and so on.

In addition, “In silico models provide a virtual space where new clean technologies, which promise resource efficiency but may cause unintended harm, can be tested at a speed and scale that may otherwise be inhibited by the precautionary principle,” the researchers write. For example, they could help cities figure out how to incorporate renewable sources of energy into the grid without compromising reliability.

Digital twins could also help scientists and policymakers to collaborate across disciplines, agencies, levels of government, and geographic distances. And they could aid cities in monitoring and reporting progress on the Sustainable Development Goals or other sustainability aims.

Some of the authors of the paper have been involved in the development of a digital twin for Fishermans Bend, an urban renewal project in Melbourne, Australia. The model includes more than 1,400 layers of both historical and real-time data from public and private sources. More than 20 government agencies and municipalities are using the model to analyze how proposed buildings will affect sunlight falling on open space and vegetation, forecast tram traffic patterns, and address other planning questions.

Digital twin models are also being used in cities including Zurich, Singapore, and Shanghai to monitor noise and pollution and facilitate urban planning that takes into account population growth and climate change.

But there are pitfalls to the digital twin approach, too. Because they require so much data, advanced computing power, and technological know-how, digital twins have the potential to exacerbate digital divides, especially between high-income and lower-income countries.

What’s more, even the most complex model may fall short in representing the multifarious nature of a real-life city. The data necessary to underpin a successful digital twin may be unavailable, inaccessible, or incompatible with other sources. And the social-science aspects of digital twins are especially poorly understood.

Finally, models can be optimized for the wrong targets. There are inherent contradictions between different Sustainable Development Goals, and programmers have to take care about how outcomes and parameters are prioritized, the researchers say. For whom and by whom are these decisions made—and who’s left out of the process?

To avoid these pitfalls of digital twins—and reap the potential benefits, the researchers recommend that governments and international institutions get involved in bridging digital divides; leaving digital twin technology to the marketplace virtually guarantees that low-resource countries will be left behind.

They also call on those creating and implementing digital twins of cities to pay attention to social and ethical responsibility. “A central question that derives from these issues is: to what extent are those who may be affected by the decisions based on simulation models included in their design and deployment?” they write.

“Interestingly in such instances, digital twins themselves can raise awareness among planners and policymakers of socioeconomic inequalities, thereby becoming instruments of inclusion,” the researchers add.

Source: Tzachor A. et al. “Potential and limitations of digital twins to achieve the Sustainable Development Goals.” Nature Sustainability 2022.

Image: ©ESRI


The finance sector can accelerate the transformation to a net-zero built environment

The finance sector can accelerate the transformation to a net-zero built environment

The finance sector can accelerate the transformation to a net-zero built environment – Here’s how

13 Mar 2023

Real estate is the world’s most valuable asset class representing two-thirds of global wealth. With more than 13% of global GDP related to construction and 12% of employment, its size means it is responsible for an astonishing 40% of global energy-related carbon emissions (14 Gt per year). This is because it makes up over one-third of global final energy use and consumes 40% of raw materials globally. Achieving net-zero carbon emissions in the built environment by 2050 will require investments of USD $1.7 trillion annually and will create half a million more direct jobs.

Real estate assets are a valuable and growing component of institutional investment portfolios. At the same time, ambitious policies and regulations, changing public awareness and radically shifting demand drivers are pushing finance sector stakeholders to focus on sustainability in their portfolios because it affects business in the short, medium and long term. When put together, the finance sector has a unique opportunity to shape demand and drive transformation in the built environment.

Achieving net-zero emissions in the built environment by 2050 is the last stop along an arduous path. The specific targets all actors need to aim for are for all newly constructed buildings to have net-zero operational emissions by 2030 and for all buildings – including existing ones – to have net-zero emissions by 2050. And embodied carbon emissions – emissions from material production and construction processes – must be at least 40-50% lower by 2030 than today and net zero by 2050. Unfortunately, we are not on track.

Halving emissions by 2030 is, therefore, the first stop and must effectively happen today. This is because the lead times in typically built environment projects can easily be 8 to 10 years, so companies planning and designing projects today must already include these targets for 2030.

Achieving this massive transformation at the speed and scale required means that all actors have to share the same vision of halving emissions by 2030 and reaching net zero across the entire life cycle by 2050. They also must deeply and radically collaborate to realize this vision – across governments, the finance sector, businesses along the full value chain, science and civil society. The collaboration needs to focus on the following three critical levers for market transformation (WBCSD and GlobalABC, 2021):

  1. Adopt whole-life carbon (WLC) and life-cycle thinking and concepts across the value chain and the market to align on key indicators, metrics and targets consistently.
  2. Treat carbon like cost: Internalize the WLC emissions costs and reflect them in the price of products and services throughout the value chain, including in governance mechanisms, procurement and taxonomy, from governments and the financial sector.
  3. Foster a positive and reinforcing supply and demand dynamic that incentivizes low-carbon solutions along the value chain. This requires signals from government and finance and, most importantly, collaboration between industry players along the whole value chain.

The role of the finance sector

Finance sector stakeholders strongly influence built environment impacts through loans and investments in built assets and – indirectly – investing in value chain businesses. When mobilizing financial capital, they can set requirements for low-carbon solutions in building projects and across the value chain. Investors, asset managers, banks, advisors and insurers all influence if and how buildings are constructed. They play a crucial role in the very early stages of buildings when decisions significantly impact their future emissions. This includes the energy performance of buildings and setting requirements to reduce emissions from building materials and the construction process.

To understand how the finance sector can exert this influence, let’s look at what holds us back today.

Challenges and opportunities

The transition’s challenges are many and complex. For instance, there is a lack of true collaboration and understanding between the construction, real estate and finance sectors, despite their deep link and reliance. Poor data availability, quality, and limited transparency are holding up measurement, benchmarking, and target-setting processes for net-zero emissions pathways. The built environment and finance sectors are facing a skills shortage in terms of understanding, writing and using reporting and disclosure documents effectively to determine how the results could drive investments. And financial services organizations have traditionally prioritized short-term financial returns over positive, but more difficult to assess, environmental, social and governance (ESG) returns.

However, in all of these, there are opportunities. Stakeholders can find new ways of working together, and legally binding contracts, for example, can help ensure the right incentives, procurement methods and metrics to support net-zero emissions goals for project delivery (see WBCSD’s Decarbonizing construction – Guidance for investors and developers to reduce embodied carbon).

Alignment on the growing number of guides, standards, tools and certifications for assessment and reporting would ensure data availability, quality and transparency (note World Green Building Council’s (WorldGBC) BuildingLife project, the RICS professional statement on whole life carbon, and the Ashrae-International Code Council (ICC) Whole Life Carbon Approach Standard).

Training and upskilling on sustainability-related disclosures and strategies to align with the Paris Agreement would ensure investors and built environment professionals see the value in these documents from both sides. They would become part of the central decision-making process for investments, linking non-financial concerns with financial impact. The Urban Land Institute (ULI) Europe’s C Change project, which is currently addressing transition risk in valuation, is an example of progress in this area. Changing the corporate culture will further the idea that the ultimate goal is to ensure strong returns on investment while creating value beyond shareholders, managing the multifaceted risks of transitioning to net-zero emissions and safeguarding people and the environment.

Understanding these and other challenges and opportunities will help the sector adapt strategies and solutions that will be the key to achieving net-zero emissions.

No-regret actions for finance sector stakeholders

Four specific interventions sit at the core of strategies to reduce the full life-cycle emissions of projects in the built environment: Accountability, Ambition, Action and Advocacy.

  • Finance stakeholders in the built environment can achieve accountability through standardized data measurement and transparent reporting.
  • In setting credible, science-based net-zero emissions targets, they raise ambition.
  • They take action by developing climate transition plans and placing whole-life carbon at the center of decarbonization strategies and decisions.
  • By working with the public sector and organizations like WBCSD and its partners in the BuildingToCOP Coalition and Global Alliance for Buildings and Construction (GlobalABC), they place advocacy for policies and regulations targeting sustainable finance at the heart of efforts to level the playing field for the market.

For asset owners and investors, achieving the transition means setting clear portfolio- and asset-specific targets and timelines. They also must embed critical climate and ESG factors into requests for proposals, investment mandates, manager selection and stewardship engagement with portfolio companies and incorporate the related risks (and opportunities) into valuations and, ultimately, into investment decisions.

For asset managers, the lack of consistent, comparable and decision-useful information on climate impact is still a barrier to better implementation. However, growing demand and regulatory pressures motivate every firm to overcome data challenges through proprietary work or third parties. Standardized frameworks and local/regional taxonomies help the asset management industry with enhanced tools for assessment, benchmarking and reporting. WBCSD’s Net-zero buildings – Where do we stand? report lays the basis for a harmonized whole-life carbon assessment and reporting framework.

Finance providers can acquire a better understanding of the emissions from the products they are financing using adequate data, tools and standards, including the cost of carbon and transition risk considerations. The ability to accurately measure and standardize (whole life) carbon emissions could help them link their financial offerings to carbon targets and potentially provide lower costs for low-carbon projects. For that to happen, they need clear and transparent information to reliably assess the business case and build trust with the market.

For insurance providers, it means developing methodologies to assess and quantify different climate change scenarios and integrating both physical and transition risks into decisions to enter or exit an underwriting.

Lastly, investment advisors and data providers can facilitate top-down learning as they share and spread best practices and become significant players in the standardization and harmonization of data and target-setting (including but not limited to the Carbon Risk Real Estate Monitor (CRREM), Science Based Targets initiative (SBTi) and GRESB).

What’s next? Achieving a breakthrough in buildings

To reduce built environment emissions globally from 14 Gt per year to 7 Gt per year seems to be a daunting task. However, with a clear focus on whole-life carbon emissions alongside cost, the finance sector can help accelerate this transition. There is evidence that we can reduce construction emissions by half today and cost-effectively. And evidence is also emerging that retrofitting building portfolios to net-zero emissions can be achieved competitively.

What needs to happen next is for all stakeholders – finance, national and local governments, and businesses along the value chain – to come together and co-develop roadmaps for a net-zero built environment that identify a clear vision, actions and accountability. Building on the aforementioned built environment market transformation levers, they can drive a united response and decisive action, thereby overcoming the fragmentation of efforts seen so far. The emerging Buildings Breakthrough with national governments committed to transforming their built environment will provide a platform to join efforts and collaborate to achieve a future in which the built environment turns from a problem into a solution to tackle climate change.

We cannot wait – because for the built environment, 2030 is today.



$220bln to build extra 1,100 km of metro rail

$220bln to build extra 1,100 km of metro rail

GCC cities should spend $220bln to build extra 1,100 km of metro rail

Global consultancy firm Strategy& says socio-economic benefits worth $700 billion can be realised by building extra metro tracks by 2030.

Image used for illustrative purpose. Getty Images , Getty Images
Image used for illustrative purpose. Getty Images
Getty Images

GCC cities will need an additional 1,100 km of metro systems by 2030, estimated to cost nearly $220 billion, global consultancy firm Strategy& said in a new report.

The cities currently have 400 km and will need the expansion of metro tracks to meet the growing population demand.

As of 2022, Dubai and Doha have 90 km and 76 km of operational metro system tracks, respectively.

Riyadh is planning to launch a 176 km metro system by 2024. Saudi Arabia will need an extra capital investment of $34 billion by 2030 in addition to the $40 billion already spent.

Meanwhile, Abu Dhabi began electric bus trials in 2019 and has outlined plans for a 131 km metro system by 2030.

Although the cost is significant, a properly implemented and funded metro system can generate three to four times in direct and indirect socioeconomic benefits.

“If cities were to build the additional roughly 1,100 km of metro rail required by 2030, they could realise direct and indirect socio-economic benefits worth around $700 billion over a 20-year period,” said Mark Haddad, Partner with Strategy& Middle East.

Ensuring that current and future metro systems achieve such returns requires a framework based on four pillars that rest upon four foundational elements. These will help cities realise the anticipated returns and implement a metro system in a cost-efficient and effective manner.

The four pillars are clear objectives, integrated planning, high-quality service & customer-centric experience and commercial mindset.

These four pillars of the implementation framework rest on four elements: effective governance; policies and incentives to support transit adoption; funding throughout system development, launch and early operations and local capabilities that enable effective long-term management.

Ruggero Moretto, Principal with Strategy& Middle East, stated that properly implemented and managed metro systems could create long-term socioeconomic returns, promote sustainability, and improve the quality of life for residents.

(Editing by Seban Scaria


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