Building Towards Zero: Existential Crisis in the Built Environment Sector
15 December 2023 - Dr Tim Forman, Senior Teaching Associate and Course Director of the Interdisciplinary Design for the Built Environment (IDBE) postgraduate courses, discusses the emission reduction challenge for the built environment sector.
With undisputed evidence that greenhouse gas emissions associated with buildings and infrastructure are a dominant driver of climate change and therefore damage to ecological systems, the industries that produce, operate, and maintain our built environments are poised for transformative change.
As global CO2 emissions continue to rise – including a 1.1% rise in emissions from fossil fuels in the last year - concentrations of CO2 in the atmosphere today are approximately 50% higher than pre-industrial levels and are far exceeding the planet’s capacity to maintain stable climate conditions. This is in large part due to emissions from energy combustion and industrial processes (see figure below). Buildings and construction are major contributors to this and account forapproximately 37% of our CO2 emissions and a similar proportion of greenhouse gasses (commonly termed ‘carbon emissions’). The sector’s emissions are at an all-time high.
Figure 1: Global CO2 emissions from energy combustion and industrial processes, 1900-2022
This is moving us at alarming speed towards existential crisis. We are rapidly approachingclimate tipping points, including the loss of ice sheets in Greenland and the Antarctic and permafrost globally, the disruption of atmospheric circulation in the North Atlantic, and the loss of coral reefs, which threatens ecosystem integrity and increases the likelihood of domino effect impacts. The built environment sector is inadvertently driving critical risks to global food, economic, social and political security.
The pathway for the built environment sector to resolve this is clear, but we are not on course in our current trajectory. The International Energy Agency (IEA) describes a route to net zero emissions that is achievable but requires steep reductions in carbon emissions by 2030 (see figure below). Without radical changes to business as usual, we are not on course to a decarbonised and nature positive future. Innovation and scaling lean and green practices are urgent priorities.
Figure 2: Global CO2 emissions from the operation of buildings in the Net Zero Scenario, 2010-2030
Last year, the IEA described milestones for 2030 that included:
All countries targeting zero-carbon-ready buildings in building codes
Renovation of nearly 20% of existing buildings to be zero-carbon-ready
Installation of approximately 600 million heat pumps, meeting 20% of global demand for heating
Approximately 100 million households relying on rooftop solar PV
Solar PV and wind generation providing approximately 40% of electricity used in buildings
350 million building units connected to district energy networks, meeting approximately 20% of space heating need
The sector stands on the brink of transformative change in everything from the design, material manufacture, construction, operation and end of life of structures, to the form and organisation of urban and rural built environments, allowing denser living with increased social and economic opportunities but reduced reliance on transport and energy-intensive living patterns.
Many have described the challenge this represents for the sector as akin to the ‘moonshot’. It is appreciably more ambitious. Decarbonising our buildings and rural and urban infrastructure is a global challenge of tremendous scale. Industrialised economies must make radical reductions in the environmental footprints of buildings while minimising the need for new construction and finding new constituent materials, components and services for necessary maintenance and construction activity. In parallel, industrializing economies must enable improvement of living standards and reduction of poverty, and in many regions, they must accommodate surging population – all while embracing new ways of building and managing built environments.
We know how to reduce the carbon associated with the operation of our built environments, but this calls for vast increases in investment, labour mobilisation and political leadership that have not yet materialised. Electrification, grid decarbonisation, behavioural changes, and mass retrofit of existing buildings to reduce the demand for energy-efficiency are enormous and largely unmet challenges. In most contexts, new buildings mustvirtually eliminate the demand for operational energy.
Even more challenging, embodied carbon, the carbon associated with the manufacture and transport of building materials and products and with the construction, maintenance and the end of life of buildings, must be reduced to near zero. This means using less material without compromising functionality, using bio-based and other ‘carbon-storing’ materials, using low-energy materials such as stone and earth, and mainstreaming the reuse of components and materials including steel, cement, and masonry in a circular economy.
This is much more than a moonshot. We are only beginning to make meaningful progress in the transition to zero carbon built environments, and this progress must be accelerated as a matter of urgency if we are to realise a sustainable future. Innovation, collaboration and transformation provide our best hopes.