While the precise idea of what the future of our buildings looks like varies depending on the region or the city, we all share a vision of a more sustainable, healthy, and inclusive building environment. Unfortunately, as modern and contemporary architecture was trying to extend the usability and the complexity of the basic human need for shelter to provide modern comforts, it has usually neglected the assumptions dictated by the building sector and market forces. However, when all building components are considered, some estimate that the construction industry is responsible for more than half of all emissions. 

Ways to reduce the carbon footprint of existing structures - Sheet1
upwards view of a glass building with partly cloudy blue skies_ ©WDM Architects

The hard truth is that buildings use 35% of energy in the world and are directly responsible for 35% of global emissions, but that also means that any adjustments we make in the sector will have a significant global impact and might as well make a real difference in the future.

How is the Building Sector Dramatically Impacting the Natural Environment? | Carbon footprint 

“Buildings are a cornerstone of our society. We spend over 90% of our time in buildings; people rely on them to survive, and they depend on the world’s finite resources to be built and operate. As they are responsible for nearly 40% of global carbon emissions, they also represent enormous potential in managing our remaining carbon budget” Cristina Gamboa, CEO of the World Green Building Council.

In general, the discussion about carbon footprint tends to focus more on transportation. However, while many people are striving to minimize carbon emissions from the transportation industry, automobiles do not account for the majority of emissions. The existing built environment, rather, is the major emitter. Speaking in numbers, in the United States for example, existing buildings consume 40% of total energy, 70% of electricity, 60% of raw materials, 12% of drinkable water, and roughly half of all greenhouse gas emissions.

While the existing structure’s impact on the environment is projected to increase in the future due to increasing population and the huge economic growth, some of the factors that contribute to a building’s carbon footprint are still evident and some are less so. 

Energy consumption in the buildings has been one of the prior factors to be considered over the last decade, and despite all the efforts made to decarbonize and reduce the electricity use, mechanical heating, and air conditioning, in addition to other equipment appliances in the indoor environment, whatever the type of building is, we are still far from completely reforming the current energy structure and stopping the disaster worldwide. 

Greenhouse gas emissions in addition to the embodied carbon in the materials used to construct the building are two lesser-known but crucial factors because their effects are often hidden and unnoticed, which puts them on par with the energy-use factor for the next three decades. 

Ways to reduce the carbon footprint of existing structures - Sheet2
How to build smart, zero carbon buildings_ © REUTERS/Henry Nicholls

Building Materials as a Fundamental Part of the Overall Problem 

For years, the building industry has been making significant efforts to improve efficiency and renewable energy usage. However, the climate implications of the construction materials in buildings are less obvious but virtually equal to those of energy supplies. From the moment these materials arrive at the project site, the atmosphere is quietly affected by many forms.

The embodied carbon properties are very different in every material, and there is not a single analysis process for all buildings. But for example, steel is widely used in huge construction projects without regard for the high energy needs for its manufacture. Concrete is another very common building material that is misused, resulting in gigantic structures that could be attained with a more “lightweight” design. Furthermore, finite resources such as copper and others are lost in waste streams.

To sum up everything that has been stated so far, the grey energy and emissions must be considered, and the extent to which the embodied carbon in building materials could be influencing the environment should be examined. However, studies and experiments have shown that it is impossible to determine the carbon footprint only from the finished product. For that particular reason, there is still, till today, an ongoing debate and research on the need to further scientific methods to improve the existing building analysis and therefore increase their performances.

Ways to reduce the carbon footprint of existing structures - Sheet3
Concrete, Steel, or Wood: Searching for Zero-Net-Carbon Structural Materials_ © By GIDEON FINK SHAPIRO

Ways to Tackle Carbon Footprint From Existing Buildings 

To tackle the carbon footprint of our buildings in general and our existing structure in particular, it seems primordial to take a hard look at the whole construction lifecycle, including the above-mentioned forms of impact (direct and indirect emissions). 

The World Green Building Council has published a general comprehensive analysis on how we can lower our embodied carbon footprint as an industry. Regarding the existing structures, as a first step, we should measure the grey emissions and the full impact of the existing buildings on CO2 emissions. This would help us to know the extent of these emissions and create a reference starting point to our Carbon reduction goals, and eventually, set a frame towards a NetZero. Therefore, we must be considering making our existing contributions and reduction targets public.

One of the main tasks to put forward to achieve the entire construction sector’s decarbonization is to point to the existing building’s interventions such as significant renovations, systems, and materials selection, equipment replacements, capital improvement cycles, zoning or use changes, and life-safety and resiliency enhancements are all examples of building intervention points (e.g. seismic, flooding, fire prevention, power disruption).

On top of this, every existing building will need to undergo energy upgrades that include a combination of energy efficiency improvements, a switch to electric or district heating systems powered by carbon-free renewable energy, and carbon-free production. 

By establishing these tasks and putting forward a selection of the most practical and impactful carbon footprint reduction solutions, we could orientate the shift of our industry towards a NetZero from where we are today.

Tall order: In fast-growing Shenzhen, China, high-rises dominate the skyline. _ ©Photographer: Billy H.C. Kwok/Bloomber  https://www.bloomberg.com/news/articles/2021-08-25/to-cut-carbon-think-low-rise-buildings-not-skyscrapers

Closing Thoughts

By 2050, the global urban population will have increased by 2.5 billion people. The world will build a city of more than 1.5 million people every week until 2050 (UN DESA, 2018). Therefore, a more sustainable future in our industry will not be achievable without the involvement of all actors — governments, the commercial sector, civil society, and communities 



Forrest Meggers, Hansjürg Leibundgut, Sheila Kennedy, Menghao Qin, Mike Schlaich, Werner Sobek, Masanori Shukuya. (2012). Reduce CO2 from buildings with technology to zero emissions, Sustainable Cities and Society, Volume 2, Issue 1,Pages 29-36. Available at: <https://doi.org/10.1016/j.scs.2011.10.001l>

Seo, S., & Foliente, G. (2021). Carbon Footprint Reduction through Residential Building Stock Retrofit: A Metro Melbourne Suburb Case Study. Energies, 14(20), 6550. Available at: <https://doi.org/10.3390/en14206550>

Online sources | Carbon footprint 

Architecture’s Carbon Problem. (2021, January 7). Blueprint For Better. Available at: <https://blueprintforbetter.org/articles/architectures-carbon-problem/>

Data to the rescue: Embodied carbon in buildings and the urgency of now. (2020, November 13). McKinsey & Company. Available at: <https://www.mckinsey.com/business-functions/operations/our-insights/data-to-the-rescue-embodied-carbon-in-buildings-and-the-urgency-of-now>

Existing Building Actions – Architecture 2030. (n.d.). Architecture 2030. Available at: <https://architecture2030.org/existing-building-actions/>

C40, Arup, and the University of Leeds with funding from Arup, University of Leeds, and Citi Foundation. (2019, August). 2020 GLOBAL STATUS REPORT FOR BUILDINGS AND CONSTRUCTION towards a zero-emission, efficient and resilient buildings, and construction sector. C40 Cities, Arup & University of Leeds.. [online] Available at: <https://wedocs.unep.org/bitstream/handle/20.500.11822/34572/GSR_ES.pdf


Oumaima is an architect and a spatial planning student passionate about arts, cultures and everything in between. She is a constant learner and a striver for continual growth, who spends most of her time, gathering inspirations, writing rad thoughts, exploring stories throughout architecture and putting colorful poems on paper & canvas.