Our Shared Understanding: a circular economy in the built environment

This article is the part of a series of op-eds from leading voices in the engineering community, addressing engineering action on sustainability, resilience, and climate change.
Authors: Mark Enzer, Strategic Advisor, Mott MacDonald; Melissa Zanocco, Head of Programmes, Infrastructure Client Group (ICG).  

We depend on the built environment for our survival but it has a huge impact on our planet. It is a major driver of climate change and ocean acidification, responsible for more than half of global carbon emissions1. Its total mass now exceeds that of everything living on the planet2.

Added to that, today’s economic model and ways of living exceed the limits of our finite planet. Therefore we need to adapt our economy, society and built environment to operate within them. To have a sustainable future, the built environment must embrace the circular economy.

The circular economy is about enabling people and nature to flourish within our planet’s capacity to provide resources and handle waste. It means getting the greatest possible value from the use of materials, products, assets and systems in the built environment. That value is ultimately defined by the social, environmental and economic outcomes we gain from the built and natural environments, not just through monetary value.

By fulfilling people’s needs while reducing environmental pressure and ensuring a secure supply of raw materials3, the circular economy aligns with the United Nations’ Sustainable Development Goals. It promotes well-being for people and the planet, offering resilience, innovation, and commercial opportunities4.

Arriving at a consensus

More than 120 people, from over 100 organisations across the built environment and circular economy communities, recently got together to agree the core concepts that inform the transition to a circular economy. By holding these principles in common, we can align policies, strategies and initiatives, enabling the built environment industries across the globe to work together towards a common goal, with coordinated action. Although ‘built environment’ is sometimes used to refer to buildings only, in this instance it is referring to everything that has been built including social and economic infrastructure.

Our Shared Understanding: a circular economy in the built environment was launched at the World Circular Economy Forum 2023 in Helsinki. It is a key enabler for achieving Our Vision for the built environment, which was co-created two years earlier using a similarly collaborative approach. Our Vision is for a built environment whose explicit purpose is to enable people and nature to flourish together for generations. This vision connects the use of the built environment with achieving better outcomes and defining value in social, environmental and economic terms.  Maximising value from the use of systems, assets, products and materials is a key enabler of this vision and unites key concepts from both the circular economy and the built environment.

Enabling better outcomes within planetary boundaries

Other sectors have directed their circular economy efforts towards the way they use materials and products. The built environment must do this too, but it can and must go further by pursuing the greatest value from the use of assets and systems as well.

We must also use design thinking to deliver higher value in use and make assets longer-lasting and easier to adapt, maintain, reuse and recycle. In this way, we will see the built environment as an important alternative source of materials to nature.

Conversely, we must view nature as a provider of vital services, not just as a source of materials. By shifting to more regenerative practices, learning from and mimicking natural cycles rather than upsetting them, we can realign our actions with the natural circular economy

Changing the whole systems

The transition towards a circular economy in the built environment demands whole system change because it is a complex system that is inextricably linked with natural cycles and social and economic models. It is crucial to adopt a systems-based approach, understanding how an intervention in one part of the system can have consequences in another.

Adopting this approach to the circular economy can therefore help in addressing other global systemic challenges, such as achieving net zero emissions, providing climate resilience, protecting biodiversity and enabling social equity. To achieve this, we must manage data more consistently and facilitate secure information flows across organisational and sector boundaries.

Making the most of data and digital approaches can help us address the scale and complexity of interconnected systems and make better decisions faster. Federated solutions, such as ecosystems of connected digital twins, can help us to understand whole systems better and intervene more effectively. This kind of ‘data infrastructure’, which promotes interoperability, is crucial for managing stocks and flows in the built environment, including existing buildings and infrastructure.

Rethinking our economic model

Economics play a significant role in the transition to a circular economy. Economic activity must be decoupled from finite resource use, with pricing mechanisms reflecting the true environmental and social costs.

To help move us forward we need to develop metrics that work for the circular economy and align better with the real needs of people and nature. We are not served well by our current focus on growth in Gross Domestic Product alone as it inevitably incentivises us to exceed planetary boundaries. Finally, we need to move towards aligned and sustainable economic, financing, business and procurement models.

Taking collective action to bring about transformation

To make this a reality we each need to choose positive change and act to make that change happen in the parts of the built environment where we have influence and control. However, this cannot be achieved by individual organisations acting alone, we need to pull together and take collective action. The interventions we collectively make in our built and natural systems need to lead to better outcomes for people and nature – helping us achieve Our Vision for the built environment. Distinct solutions will be needed in different parts of the world but by embracing global diversity and sharing learning we can move faster and further together.


  1. H. Ritchie, M. Roser, P. Rosado (2020). “CO₂ and Greenhouse Gas Emissions”. Published online at OurWorldInData.org ‘ourworldindata.org/co2-andgreenhouse-gas-emissions’
  2. E.Elhacham, L. Ben-Uri, J. Grozovski,Y.M.Bar-On and R. Milo (2020). Global human-made mass exceeds all living biomass, Nature fisherp.mit.edu/wp-content/ uploads/2021/01/s41586-020-3010-5.pdf
  3. European Parliament, Circular economy: definition, importance and benefits. Ref.: 20151201STO05603, www.europarl.europa.eu/news/en/headlines/ economy/20151201STO05603/circular-economydefinition-importance-and-benefits
  4. P. Lacy, J. Rutqvist (2015). Waste to Wealth – The Circular Economy Advantage, New York/London: Palgrave Macmillan

About the Authors:

Mark Enzer, OBE FRAEng, is a Strategic Advisor to Mott MacDonald and Royal Academy of Engineering Visiting Professor in the digitalisation of the built environment at Cambridge. He is a keen champion of innovation in the context of collaborative delivery models and particularly interested in the transformation of the infrastructure industry, including: systems-thinking, digital transformation, connected digital twins, data infrastructure, low-carbon sustainable solutions and the circular economy in the built environment. As the former Head of the National Digital Twin Programme, he contributed to the leadership of the ambitious programme to enable an ecosystem of connected digital twins across the built environment. For five years as Mott MacDonald’s Chief Technical Officer, he was accountable to the Executive Board for technical excellence across the Group. He is the Digital Transformation workstream lead as part of Project 13 for the Infrastructure Client Group and lead author of the Infrastructure Carbon Review, published by HM Treasury.

Melissa Zanocco OBE is Head of Programmes for the Infrastructure Client Group (ICG), as well as one of the instigators of Our Vision for the Built Environment, and is committed to transforming the built environment sector to produce better outcomes for people and nature. She is Co-Chair of both the Project 13 Adopter Community and the Digital Twin Hub Community Council as well as a member of the United Nations Industrial Development Organisation’s Deep Decarbonisation Initiative, World Economic Forum Digital Twin Cities Project Global Advisory Committee and Construction Leadership Council Task Force. She is also a member of the UN Women UK community, including as part of the delegation to the 67th session of the Commission on the Status of Women 2023.