Earth Today | ‘Avoid, shift, improve’

A NEW report has noted the “urgent need” for new models of cooperation for the decarbonisation of building materials if the world is to succeed in realising net zero emission goals, which are seen as pivotal to the climate fight.

This comes against the background of a built environment sector that currently accounts for a reported 37 per cent of global greenhouse gas emissions, which fuel increasing temperatures and trigger a variety of climate impacts, from rising sea levels to extreme weather events.

Emissions which fuel increasing temperatures and trigger a variety of climate impacts, from rising sea levels to extreme weather events.

“Until now, most of the progress in the sector has been made on reducing the ‘operational carbon’ of a building – the emissions created from heating, cooling and lighting, which are projected to decrease from 75 per cent to 50 per cent of the sector in the next few decades. However, solutions for reducing the ‘embodied’ carbon emissions from the design, production and deployment of building materials such as cement, steel, and aluminium have lagged far behind,” cautioned the report, titled Building Materials and the Climate: Constructing a New Future and published by the United Nations Environment Programme (UNEP).

“The reasons for this are complex and many actors are involved.Therefore, the incentives for decarbonisation need to simultaneously enable decision-makers, from producers to consumers across the global material supply chains, in both informal and formal building sectors,” it added.

The report has therefore championed three pathways to a resolution and which supports stakeholders across the lifecycle of the built environment sector.

One pathway is focused on avoiding waste and building with less, together with enhanced circularity, while another is making the shift to sustainably sourced bio-based building materials.

“Renewable, bio-based building materials have a unique capacity to drive reductions in atmospheric carbon, if they are sustainably sourced and managed. Currently, wood is the leading scalable biomaterial, and patterns of timber production and use offer both opportunities and challenges,” it explained.

“The rising demand for timber could accelerate markets for upcycling by-products from forests and agriculture, adding the massive potential benefits of reducing forest fires and greatly expanding the carbon sequestration potential of both forests and urban areas by up to 70 per cent in certain regions,” the report noted.

“However, a key prerequisite is that intersectoral approaches to renewable resource and land management are urgently required to transition away from the high carbon impacts of much ‘business-as-usual’ forestry and agriculture,” it said further.

Among the key recommendations for bio-based materials, the report noted, are “standardisation of performance, integration into building codes, broad industry upskilling, marketing and financial incentivisation, and regulated cooperation in sustainablel and-use techniques”.

The third pathway is concerned with the adoption of improved methods “to radically decarbonise conventional materials such as concrete, steel and aluminium, and only use these non-renewable, carbon-intensive, extractive materials when absolutely necessary”.

There is also, the report noted, an important opportunity in forests.Where the production of building materials is linked to the carbon cycles of forests and agricultural land, it explained, there are some distinct benefits to be had.

“This would produce compounding benefits, from reducing the risk of forest fires to increasing the productivity of forested and agricultural land tracks through rejuvenation and responsible reforestation,” it said.

At the same time, it has called for increased investment to support the varied efforts that are required, as well as for policy support.

“Policies to support material producers and users across the building life cycle range from land-use management to carbon certifications. However, the effects of material selection on ecosystems need to be better incorporated into assessments,” it said.

“Global cooperation is critical towards ensuring a just transition to ethical decarbonisation. Stakeholders in the building process must have access to reliable data on the provenance (place of origin) of materials, to ensure that carbon taxes and other regulations are not greenwashing material products that have been made with unfair labour, or are detrimental to local biodiversity and the life quality and expectancy of regional populations,” the report added.

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