The built sector globally and within Africa has a vital role to play in responding to the current climate emergency given that buildings are currently responsible for 39% of global carbon emissions.

Words WORDS David Baggs, CEO, Global GreenTag

DECARBONISING THE AFRICAN BUILT ENVIRONMENT: A materials and certification perspective

The built sector globally and within Africa has a vital role to play in responding to the current climate
emergency given that buildings are currently responsible for 39% of global carbon emissions. Decarbonising the sector is one of the most cost-effective ways to mitigate the worst effects of climate breakdown.

In 2018, in line with the ambitions of the Paris Agreement and to accelerate the built environment sector towards a 1.5ºC pathway, the World Green Building Council (WorldGBC) launched the Net Zero Carbon Buildings by 2050 Commitment. Embodied carbon contributes around 11% of global carbon emissions. Carbon emissions released before the infrastructure begins to be used, previously known as embodied carbon are increasingly being called “upfront carbon” for clarity and unless addressed, will be responsible for half of the entire carbon footprint of new construction between now and 2050. This growth threatens to consume a large part of the remaining global carbon budget if left unchecked.

The WorldGBC as well as numerous country-based GBCs including South Africa have endorsed the enhanced focus on tackling upfront carbon emissions at the same time as moving to eliminate net operational emissions by 2050.

GBCSA uses its Green Star framework to support a common understanding of what a green building is within the South African property sector, as well as Green Building Councils throughout Africa including Ghana, Nigeria, Mauritius, Namibia, Rwanda, Uganda, Tanzania and Zimbabwe to achieve locally relevant context conditions within other African countries.

GBCSA has embarked on an industry collaborative process of updating the Green Star framework and what defines a green building for new buildings. A key focus of this revision is to set clear goals around decarbonising the upfront carbon emissions of certified buildings with a 2050 goal of net-zero carbon buildings both from upfront and operational emissions points of view.

The obvious question to ask is, “How likely is the industry going to be able to achieve the objective of reducing upfront carbon emissions to the goal level of net zero?” given that material processing and building operations make up a significant chunk (about 95%) of these emissions and for the industry to even make a dent, substantial change and innovation will be needed in a generally highly risk averse industry.

Decarbonisation from the material and embodied carbon perspective means taking on unparalleled innovation challenges and changes in processes and supply chain decision-making. One of the major questions this creates is on what basis does one makes the decisions needed to drive change in the correct direction without generating unintentional consequences eg increasing other chemical pollutants or water consumption.

GBCSA uses its Green Star framework to support a common understanding of what a green building is within the South African property sector, as well as Green Building Councils throughout Africa.

One tool that can enable both innovation and responsible supply chain decision-making is the study of Life Cycle Assessment (LCA). LCA as a tool allows for the estimation of all the impacts, including carbon emissions for building materials from the raw material extraction phase, through manufacturing, packaging, transport etc through to fate of the product at the end of its initial “life”.

The analysis involved in LCA can be used internally by product manufacturers to identify hotspots in impacts including carbon emissions within the supply chain and inform decisions on how to reduce the emission intensity of any specific hotspots of concern. LCA studies generate data that quantifies impacts across a wide range of indicators and when used as a carbon hot-spotting tool, supports decision-making to incorporate innovative low carbon ingredients or processes and assists, where information is available, in choosing lower carbon alternatives. In totality, all of these components together are described as “upfront carbon” in the GBC Australias new Green Star “Buildings” rating tool. Decarbonising buildings requires low carbon materials and both manufacturers and indeed projects need to start the process of decarbonising supply chains with assistance from LCA. LCA generates volumes of complex “inventory” data to develop the final set of indicators that include the total upfront carbon emissions data. Much of this LCA inventory data is highly confidential and will never be

released even to the client involved because it often involves the direct provision of classified information from third party suppliers under non-disclosure agreements. So, the ability to communicate the results of the LCA depends on summarised “rolled-up” and de-identified data published in standardised formats and mandatory minimum content according to various international standards.


The WorldGBC, GBCSA and building materials industry internationally has adopted EN15804 +A2: Sustainability of construction works – Environmental Product Declarations – Core rules for the product category of construction products as the accepted standard to publish these summary LCA reports or “EPDs” under to maximise potential comparability of products from different manufacturers and LCA providers. EPDs are the starting point that allow various stakeholders to review and discuss how they can contribute to decarbonising the built environment.

They are in effect the “language” via which manufacturers communicate to the rest of the industry the environmental and carbon profile of their products and the tool via which architects, designers, engineers, builders and indeed their project LCA consultants can drive the decarbonisation process by preferred low carbon product and materials selection based on the data within EPDs, not just the provision of an EPD. “One of our local challenges around LCAs and accurately assessing upfront embodied carbon is the lack of local and contextually developed databases for materials and their embodied carbon impact,” explains Georgina Smit, GBCSA Head of Technica

The building tool, which is under consideration, could be step one in the ratchetting up the decarbonisation process by Green Star between now and 2050.

One approach being considered, from a calculation point of view in Green Star, is an “upfront carbon emissions calculator” to enable a project team to calculate their embodied carbon impacts from key and generic products and materials used in the building’s construction. It aims to be a simple calculator for those not doing a whole-of-project LCA study and is measured in kgCO2e.

An alternative approach would require a project to capture LCA data from various sources including preferably product specific EPDs but also less preferred generic or industry average data based EPDs and compares the building and its specified products and materials against a reference building modelled by the project team using nominated benchmark materials. This is a much more complex process and necessitates the use of EPDs from manufacturers to allow design teams to select upfront carbon emissions preferred materials. Hence it is this specific credit that is driving
the major increase in demand by typically the larger projects for EPDs from manufacturers and suppliers

Decarbonisation from the material and embodied carbon perspective mean taking on unparalleled innovation challenges and changes in processes and supply chain decision-making


The GBCSA Green Star new tool development task force is evaluating how this process can be made to be “user-friendly”, accessible to a wide scale of projects sizes and typologies. The South African market has taken some early steps in the direction of understanding the environmental impacts of products and materials, namely 3rd party eco-label certification programmes. But now the built environment industry needs to be further incentivised and supported with appropriate information to make the best decisions and to get to our goals.

“Projects are increasingly reaching out to the GBCSA on guidance about whole life carbon vision – in other words, extending their focus beyond the operational energy consumption to include the upfront embodied carbon associated with the bricks and mortar of the building. This is why the GBCSA is delighted that upfront embodied carbon is a prerequisite for consideration in the new framework and we are also developing criteria to aid projects in declaring a net zero carbon status with regard to upfront embodied carbon. These are two exciting developments that we hope will support this exploratory learning curve that the industry is embarking on,” says Smit.

As alluded by a recent Australian industry report, embodied carbon will be responsible for over 80% of Australia’s built environment emissions by 2050 if steps are not taken by everyone involved. Similar impacts are likely for South Africa.
Looking at the growing uptake in the use of Green Star within Africa, there is no doubt that the building industry at large can unlock the potential to decarbonise the built environment by adopting policy to suit local conditions and potentially increase the use of Green Star® and encouraging the use of tools such as LCA and EPDs for decision-making across all spheres of the industry. The dire consequences of not getting rapid control of and dramatically reducing the industry’s carbon footprint locally and globally, do not bear thinking about.