If the world is to avoid the worst predicted effects of climate change, every industry must rapidly and comprehensively reduce its greenhouse gas emissions, the main driver of global warming since the Industrial Revolution. In line with achieving net zero emissions by 2050 and limiting global warming to 1.5oC above pre-industrial levels, the UN has announced a new plan to decarbonize the construction sector, traditionally one of the most polluting industries globally.
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What is the Impact of the Global Construction Industry?
The environmental impact of the construction sector is well known. Rapid urbanization over the past couple of centuries, coupled with technological development and the use of more carbon-intensive materials and practices, has contributed to dangerously high levels of greenhouse gas emissions.
Take, for example, the production and use of concrete. The manufacture of this key construction material is, according to many experts, responsible for around 8% of the total greenhouse gas emissions produced worldwide annually. Reducing the use of concrete in new structures would play a critical role in reducing emissions.
Overall, the construction sector is responsible for over two-thirds of global CO2 emissions, and this problem, if unaddressed, could grow. In respect to urbanization, it is estimated that every five days, enough buildings to fill modern-day Paris are added to the global urban construction stock.
If a comprehensive and effective plan for curtailing greenhouse gas emissions and the environmental damage wrought by global construction is not implemented swiftly, it will be extremely difficult for the sector to meet its net zero emissions commitments in line with agreements such as COP26 and the Paris Agreement.
What is the Plan?
The plan, published in a new report by the UN Environmental Program (UNEP) in conjunction with Yale University, prioritizes a circular approach to construction, which will reduce waste, resource exploitation, and carbon dioxide emissions in the sector.
A key recommendation in the UN’s plan is to phase out some carbon-intensive construction materials in favor of bio-based materials such as biomass and timber. This, the report states, could save around 40% of carbon emissions by 2050, which would be in line with internationally agreed net zero commitments.
However, this switch could be difficult as not all construction materials can be easily replaced. The manufacture of concrete, aluminum, and steel would need to be rapidly decarbonized.
The report highlights some approaches which will help achieve this. Chief amongst these strategies include electrifying production, using more recycled materials, and bringing innovative technologies to the mass market.
As mentioned previously, concrete is one of the most carbon-intensive building materials in use today, and in order to meet decarbonization targets, the use of new concrete will need to be halved by 2060. Production should transition to a circular model, with two thirds of concrete manufactured this way.
The remaining one third, according to the authors of the report, should be made using innovative low-emissions cement. Several companies have been working on introducing this type of building material to the mass market in recent years.
Steel and concrete usually end up in landfill at the end of a structure’s useable life, which contributes to the climate crisis. Once wasted, these potentially recyclable materials are essentially lost and can cause environmental pollution as well as being a critical economic and social challenge, especially in developing nations.
In addition to changing production methods and materials, governments can play a role in this shift to a green future by providing incentives, policy recommendations, and introducing regulations that will spur industry action.
A Return to Past Construction Paradigms
The report has been described by its authors as a “back-to-the-future” revolution. Most of the unsustainable practises in the construction sector have arisen since the mid-20th century, with buildings in previous centuries largely constructed from local materials such as timber and stone, with climactic conditions in mind.
Building materials were largely recycled locally and reused. However, with the rise of cheap concrete use and a global, interconnected construction industry, more toxic, polluting, and extractive methods rose to prominence. This has led to the urgent issues faced by the industry and wider society today.
A return to thinking about construction as a local, sustainable, and societally beneficial economic activity would go a long way to scaling back the environmental impact of the sector. Innovative approaches and methods which utilize advanced materials, government policy, and circular working practises are urgently needed.
Decarbonizing the global construction industry is vital if the worst effects of climate change are to be avoided. This report goes a long way to addressing these issues and providing a roadmap to a greener, more sustainable way of thinking about future urban design and development.
Whilst highlighting the sense of urgency needed, the authors have stated that this will be a gradual process, as change cannot happen overnight due to the complexity of the issue. However, with the right action in conjunction with other industries, such as the agricultural and forest sectors, it is possible.
Finally, the report has stated that “breakthrough commitments” could be made by some nations at November’s UN climate talks in Dubai. This would bring the construction industry in line with other sectors such as steelmaking, energy, and agriculture.
More from AZoBuild: Sustainable Challenges in the Cement Industry
References and Further Reading
UN Environment Program (2023) UN plan promises massive emission cuts in the construction sector – the most polluting and toughest to decarbonise [online] unep.org. Available at:
The Straits Times (2023) UN maps out decarbonisation of polluting construction sector [online] straitstimes.com. Available at: