The built environment sector is one of the largest contributors to climate change, responsible for more than a third (37 percent) of global energy-related carbon emissions (United Nations  Environment  Programme [UNEP]  2022,  see Figure 1.1). Yet the built environment has received only a small fraction of climate-focused funding for research and development compared to other sectors. Although investments in the energy efficiency of building operations increased 16 per cent among Group of Seven (G7) countries 1 in 2021 (ibid.), such commitments pale in comparison to what is required to decarbonise the built environment. As the largest global industrialised sector, construction also has widespread social impacts; it is at the highest risk of forced labour, with lax environmental and labour regulations tending to coincide (Grace Farms Foundation 2022).
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As both population and wealth continue to grow globally, humanity is building more than ever in a quest to secure comfort and well-being. Floorspace worldwide is set to double by 2060, and every five days the world adds enough new buildings to total the size of Paris (UN Environment Programme [UNEP] and International Energy Agency [IEA] 2017). According to a 2019 report from the Organisation for Economic Co-operation and Development (OECD), the global consumption of raw materials will nearly double by 2060 as the world economy expands and living standards rise, doubling the environmental overloading being experienced today. The OECD projects that if we continue“business-as-usual” practices, the biggest increase in resource use by 2060 will be in extractive minerals, particularly in developing economies (OECD2019).

These megatrends are also influenced by rapid urbanisation. In 2020, the 124 countries that dominate the developing world were home to 81 per cent of the world’s population, and this share is projected to reach 87 per cent by the end of the century (Roser and Rodés-Guirao 2013; United Nations Department of Economic and Social Affairs 2020; World Bank n.d.). Much of this future population growth will occur in cities. The World Bank estimates that to meet the rapid increase in urban populations, 300 million additional houses will need to be constructed by 2030 (World Bank 2022a). Enabling this global building boom requires a new agenda for decarbonisation to meet residential needs of developing countries while decarbonizing the full range of building types globally, from formal to informal (see Box 1.1).

In the absence of urgent action, the carbon emissions of common construction materials such as concrete, steel and aluminium are projected to grow to increasingly dangerous levels. Although developed countries have historically contributed the vast majority of global carbon emissions, the world’s top 10 greenhouse gas-emitting countries now include rapidly developing countries such as China, India and Iran (Islamic Republic of) (Nejat et al. 2015). Even with the implementation of widely accepted interventions, emissions from the built environment sector are projected to go far beyond what is allowable to keep global temperature rise within 1.5 degrees Celsius, the target set under the 2015 Paris Agreement on climate change (Cao et al. 2021).

This report outlines concrete pathways to reverse these projections, and even to reach net zero emissions in the built environment sector by mid-century, through the promotion of best available technologies for conventional materials, combined with a major push to advance circular recycling and bio-based materials from forest and agriculture streams.