Technological efficiency limitations to climate mitigation: Why sufficiency is necessary

A key global challenge of the United Nations' 2015 Paris Agreement is to constrain global warming to 1.5°C. This critique of the 'Buildings Breakthrough' agenda draws on existing literature and asks whether a technological approach to limiting greenhouse gas (GHG) emissions from the built environment is adequate to meet the Agreement’s objectives. Efforts to reduce emissions within this sector have focused upon clean technology (cleantech), e.g. clean energy, efficiency and circularity. Could sufficiency policies with a demand-side perspective have a significant role? Although the Intergovernmental Panel on Climate Change (IPCC) emphasised that the aggressive and immediate introduction of sufficiency policies was necessary to attain the Agreement, the importance of sufficiency in constraining growth of the building stock and (per capita) floor area is not yet part of the policy mix. Such policies are urgently needed to complement cleantech approaches, which form the focus of the so-called 'Breakthrough Agenda'. The implication for the construction sector in the Global North is a shift away from new build toward long-term stewardship and adaptation of the built environment. For the Global South, growth of the built environment is needed to accommodate population growth and urbanisation, but requires an approach emphasising sufficiency in space, services and accessibility. POLICY RELEVANCE The direction taken by the 'Buildings Breakthrough' will have critical implications for buildings, infrastructure and construction, and the sector’s contribution to climate mitigation and other global challenges. Policies based upon clean technologies and resource efficiency alone are likely to fall short of the stated ambitions to limit GHG emissions because efficiency gains are often offset by growth in floor area and built-up land. Therefore, additional policies and measures are needed to constrain material-driven growth and consumption carbon, with sufficiency at the forefront. This synthesis paper illustrates how the principle of avoiding and reducing demand for materials and land, hitherto largely overlooked in policy settings, may be applied at various scales, ranging from urban to precincts, and to buildings.