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Integrating Circularity
in Buildings and
The buildings and construction sector consumes a large quantum of non-renewable resources and generates a huge amount of waste and emissions across its value chain, starting right from the extraction of virgin resources for production of building materials to the construction activity itself, during the operational life of the building and finally its end-of-life treatment. Considering that globally in 2019, the building and construction sector was estimated to account for up to 28 percent of total energy consumption and 38 percent of energy-related carbon dioxide emissions (United Nations Environment Programme, 2021), the environmental burden of the sector is evident and demands urgent attention from decision-makers. Playing host to the highest concentration of human activity, cities have become the hubs of unsustainable production and consumption patterns. Cities cover only 2% of the world’s surface but consume over 75% of the planet’s resources (IRP, 2018). Moreover, demand for resources in urban areas is ever growing, especially in developing countries where a high proportion of the projected construction activity is expected to happen over the coming decades. Almost 37% of the estimated urban population growth by 2050 is expected to come from India, China and Nigeria (UN-DESA, 2014), further increasing demand for housing and infrastructure. In India, it is estimated that 70% of the buildings that will be standing in 2030 are yet to be constructed (IRP, 2018). Combined impacts of this rapid urbanisation and the accompanying surge in the building and construction activity raise urgent alarm bells with respect to the resource-hungriness of the sector while also presenting a vital opportunity to address the ever-increasing concerns arising from extractive and unsustainable building practices. Among the many contemporary schools of thought addressing sustainability issues, the Circular Economy model is gaining prominence with a new systemic approach towards shifting from a linear production and consumption model of take-make-dispose to a more holistic approach that treats waste from one process as food for another and encourages closed loop systems that design out the waste and try to keep materials in active circulation for as long as possible. Another explanation of the concept comes from the United Nations Environment Programme (2018) which “acknowledges that a more circular economy, one of the current sustainable economic models, in which products and materials are designed in such a way that they can be reused, re-manufactured, recycled or recovered and thus maintained in the economy for as long as possible, along with the resources of which they are made, and the generation of waste, especially hazardous waste, is avoided or minimised, and greenhouse gas emissions are prevented or reduced, can contribute significantly to sustainable consumption and production." The model is well-represented by the ‘Butterfly Diagram’ (see Figure 1) by the Ellen MacArthur Foundation (2019) which presents a framework for understanding the interplay of loops in both biological and technological cycles of any product.
Figure 1: Butterfly Diagram for Circular Economy Systems (Ellen Macarthur Foundation. 2019) Applying this approach to the buildings and construction sector requires a thorough evaluation of the processes adopted at all stages of the value chain to understand the underlying complexities of the challenge. A breakdown of the steps (see Figure 2) shows that gaps in strategies towards resource efficiency often arise as decisions around resource usage are made in different stages while the actual consumption happens in other stages with a markedly different set of involved stakeholders. This results in ineffective communication and poor implementation of any planned initiatives.
Figure 2: The construction value chain (United Nations Environmental Programme, 2021) Reanalysing this value chain requires a more all-encompassing approach and considerable deliberation of the varied impacts at each step. For instance, the demand for land for new construction activities as well as for extraction and manufacture of building materials often encroaches on fertile land and forest areas, thereby reducing the land available for agriculture and also leading to biodiversity loss, deforestation and reduced carbon sequestration (United Nations Environment Programme, 2021). Material-related emissions from the production of bulk materials used in construction such as iron and steel, cement, lime and plaster as well as plastics and rubber represent over 23% of overall global emissions (IRP, 2020). About 30% of materials, such as gravel, limestone and crushed rock, extracted from the earth are used in construction (United Nations Environment Programme, 2021). The operational life of the built environment adds further pressure with high usage of resources across long life spans, often over 50 years. For example 25% of all water and 12% of potable water used globally are associated with buildings (IRP, 2017). In most cases, little to no planning is done towards management of waste at the end of its life with most demolition waste being disposed of in landfills except materials such as metal, timber and glass getting recycled. The multifarious socio-environmental impacts of the sector and the extensive network of processes and stakeholders involved in the construction sector, along with the long life-span of the buildings, indicate an urgent need to address issues along the complete value chain to avoid long-term lock in of carbon intensive building practices, especially in developing countries who are now charting pathways for low-carbon, resilient and responsible growth trajectories. There is tremendous potential to consider wastes from current production systems that may be utilised in construction processes. For instance, industrial wastes like blast furnace slag and sludge from steel-making industries are being used to produce substitutes for aggregates and sand to be used in concrete. Captured fly ash from thermal power plants is being used in cement production as well as for making bricks and paver blocks. Construction and demolition waste itself may be utilised for production of building materials. The circularity mandate provides key solutions to many pressing resource challenges but requires a systemic shift in thinking to drive tangible and transformational change. In the current scenario, integrating circularity in the construction sector requires strong focus on:
Such an approach may also help align local development plans with the vision and trajectories of Agenda 2030. Circularity principles in the construction sector directly address SDG 12 (Responsible Consumption and Production), SDG 11 (Sustainable Cities and Communities), SDG 6 (Clean Water and Sanitation), and SDG 13 (Climate Action). Additionally, they also have the potential to contribute to SDG 8 (Decent Work and Economic Growth), SDG 3 (Good Health and Wellbeing), SDG 7 (Affordable and Clean Energy), and SDG 5 (Gender Equality). This alignment allows for the opportunity to garner support and also attracting attention and investment from global policy stakeholders and funders. It is evident that the massive environmental impacts of the building and construction sector need urgent attention in light of the rapid growth in our cities. Mainstreaming circularity principles into the sector requires a significant change in mindsets and the questioning of existing paradigms through adoption of a systems thinking approach based on a deep understanding of cycles and feedback loops. A deliberate focus needs to be constantly maintained on retaining the value of resources through the different lifecycle stages while also diversifying options and eliminating waste from current practices. It is here that a collaborative approach becomes ever-necessary to encourage knowledge-sharing and partnerships across the public and private sectors as well as civil society and consumers to fundamentally rethink our collective relationship with the products and services we use. ■ Bibliography:
Mohak Gupta |
