The UN Environment Programme (UNEP) has this week published a plan to decarbonise the world's buildings and construction sector using an “avoid-shift-improve” solution.
Rapid urbanisation means that the world needs to add buildings equivalent to the size of Paris every five years, with the built environment sector already responsible for 37% of global emissions.
However, in a new report, the UNEP offers policy makers, manufacturers, architects, developers, engineers, builders and recyclers a “three-pronged solution” to reduce “embodied carbon” emissions and negative impacts from the production and deployment of building materials.
The first principle is to ‘avoid’ waste through a circular approach, building less and repurposing existing buildings – which generates 50-75% fewer emissions than new construction – using less materials and those that have a lower carbon footprint, and facilitating reuse or recycle.
The ‘shift’ principle involves ethically and sustainably sourcing renewable, bio-based building materials, including timber, bamboo, and biomass, which could lead to compounded emissions savings of up to 40% in many regions in the sector by 2050.
While the ‘improve’ principle involves decarbonisation of conventional materials that cannot be replaced – mainly concrete, steel, and aluminium, glass and bricks – focusing on electrifying production with renewable energy, increasing the use of reused and recycled materials, and scaling innovative technologies.
The avoid-shift-improve solution also requires 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.
“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.”
Government intervention is required across all phases of the building life cycle – from extraction through to end-of-use – to ensure transparency in labelling, effective international building codes, and certification schemes, according to the report.
Investments in research and development of nascent technologies, as well as training of stakeholders in the sectors, are needed, along with incentives for cooperative ownership models between producers, builders, owners, and occupants to the shift to circular economies.
The report also highlights case studies from Canada, Finland, Ghana, Guatemala, India, Peru, and Senegal, demonstrating how decarbonisation takes places using the ‘avoid-shift-improve’ approach.
“The decarbonisation of the buildings and construction sector is essential for the achievement of the goal of limiting global warming to 1.5°C,” 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.
“By providing cutting-edge scientific insights, as well as very practical recommendations to reduce embodied carbon, the study advances our joint mission to decarbonise the sector holistically and increase its resilience.”
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