By Joyce Ojanji

With the rapid urbanization worldwide meaning every five days, the world adds buildings equivalent to the size of Paris, with the built environment sector already responsible for 37 percent of global emissions, however, a new report offers decarbonization solutions in the sector.

The report titled Building materials and the climate: Constructing a new future was produced by the United Nations Environment Programme (UNEP) and the Yale Center for Ecosystems + Architecture (Yale CEA), under the Global Alliance for Buildings and Construction (GlobalABC).

It offers policymakers, manufacturers, architects, developers, engineers, builders and recyclers a three-pronged solution to reduce “embodied carbon” emissions and the negative impacts on natural ecosystems from the production and deployment of building materials.

According to the report, the three-pronged Avoid-Shift-Improve solution needs to be adopted throughout the building process to ensure emissions are slashed and human health and biodiverse ecosystems are protected. The solution also requires, in its implementation, sensitivity to local cultures and climates, including the common perception of concrete and steel as modern materials of choice.

“Until recently, most buildings were constructed using locally sourced earth, stone, timber, and bamboo. Yet modern materials such as concrete and steel often give only the illusion of durability, usually ending up in landfills and contributing to the growing climate crisis,” said Sheila Aggarwal-Khan, Director of UNEP’s Industry and Economy Division.

She noted that the net zero in the building and construction sector is achievable by 2050, as long as governments put in place the right policy, incentives and regulation to bring a shift the industry action.

“The decarbonization of the buildings and construction sector is essential for the achievement of the goal of limiting global warming to 1.5°C. By providing cutting-edge scientific insights as well as very practical recommendations to reduce embodied carbon, the study ”Building materials and the climate: Constructing a new future” advances our joint mission to decarbonize the sector holistically and increase its resilience”, said Dr. Vera Rodenhoff, Deputy Director General for International Climate Action and International Energy Transition of the German Federal Ministry for Economic Affairs and Climate Action (BMWK), which together with the German Federal Ministry for Economic Cooperation and Development (BMZ) has funded the study.

To date, most climate action in the building sector has been dedicated to effectively reducing “operational carbon” emissions, which encompass heating, cooling, and lighting. Thanks to the growing worldwide decarbonization of the electrical grid and the use of renewable energies, these are set to decrease from 75 percent to 50 percent of the sector in the coming decades.

Since buildings contain materials produced in disparate regions across the globe, reducing “embodied carbon” emissions from the production and deployment of building materials requires decision-makers to adopt a whole life-cycle approach. This involves harmonized measures across multiple sectors and at each stage of the building lifecycle – from extraction to processing, installation, use, and demolition.

Case studies from Canada, Finland, Ghana, Guatemala, India, Peru, and Senegal, demonstrate how decarbonization takes place using “Avoid-Shift-Improve” strategies: developed economies can devote resources to renovating existing aging buildings while emerging ones can leapfrog carbon-intensive building methods to alternative low-carbon building materials.

Cities worldwide can drive the implementation of decarbonization. Many are already integrating vegetated surfaces, including green roofs, façades, and indoor wall assemblies to reduce urban carbon emissions and cool off buildings, increase urban biodiversity and more.