On April 4th, the UN's Intergovernmental Panel on Climate Change (IPCC) published a new report on the mitigation of climate change. Unveiling a plan for much-needed cuts in carbon dioxide emissions to limit the root causes of dangerous climate change.
As reported, the construction sector is responsible for up to 16% of greenhouse gas emissions. A mind-boggling number. Luckily, bottom-up studies show that up to 61% of global building emissions could be mitigated by 2050. If we act now!
In this article, we’ve rounded up all the action points from the report concerning the building sector. Let’s have a look at how we can create a better planet together!
1. What’s the status of emissions from construction right now?
Net anthropogenic GHG emissions have increased since 2010 across all major sectors globally. An increasing share of emissions can be attributed to urban areas. Emission reductions in CO2 from fossil fuels and improved industrial processes have happened. But they are less than emissions increases from rising global activity levels in industry, energy supply, transport, agriculture and buildings.
In 2019, approximately 6% of total net anthropogenic GHG emissions came from buildings. If emissions from electricity and heat production are attributed to the sectors that use the final energy, 90% of these indirect emissions are allocated to the industry and buildings sectors, increasing their relative GHG emissions shares from 24% to 34%, and from 6% to 16%, respectively.
2. For industrial processes, like offsite construction, circular material flows are key.
Achieving net-zero CO2 emissions from the industrial sector is challenging but possible. It will require action throughout value chains to promote all mitigation options, including demand management, energy and materials efficiency, circular material flows, as well as abatement technologies and transformational changes in production processes. Next to that, the industry will have to manage carbon and adopt new production processes using low and zero GHG electricity, hydrogen, and fuels.
Light industry, mining and manufacturing have the potential to be decarbonised through available abatement technologies (e.g., material efficiency, circularity), electrification (e.g., electrothermal heating, heat pumps) and low- or zero- GHG emitting fuels (e.g., hydrogen, ammonia, and bio-based & other synthetic fuels).
Electrification and circular material flows will contribute to reduced environmental pressures and increased economic activity and employment. However, some industrial options could impose high costs.
3. There is great potential in sustainable options for basic materials.
The use of steel, cement, plastics, and other materials is increasing globally. Sustainable options for demand management, materials efficiency, and circular material flows can contribute to reduced emissions, but how these can be applied will vary across regions and different materials. But because these options are relatively new, they are generally not considered in recent global scenarios nor in national economy-wide scenarios. As a consequence, the mitigation potential in some scenarios is underestimated.
“These sustainable options require more attention from industrial policy to reach their potential for mitigation.”
For almost all basic materials ‒ primary metals, building materials and chemicals ‒ many low- to zero- GHG intensity production processes are at the pilot to near-commercial and in some cases commercial stage but not yet established industrial practice. Introducing new production processes for sustainable basic materials could increase production costs, but is expected to translate into minimal cost increases for final consumers.
Hydrogen direct reduction for primary steelmaking is near-commercial in some regions. Until new chemistries are mastered, deep reduction of cement process emissions will rely on already commercialized cementitious material substitution and the availability of carbon capture and storage (CCS).
Reducing emissions from the production and use of chemicals would need to rely on a life cycle approach, including increased plastics recycling, fuel and feedstock switching, and carbon sourced through biogenic sources, and, depending on availability, carbon capture and utilization (CCU), direct air CO2 capture, as well as CCS.
4. From building codes to choice of materials: cities policies play a significant role.
A growing number of cities are setting climate targets, including net-zero GHG targets. But urban consumption patterns and supply chains reach further than the cities’ administrative boundaries. Regionally and even globally. Those have to be addressed as well to reach the full potential for reducing consumption-based urban emissions.
Cities can play a positive role in reducing emissions across supply chains that extend beyond cities’ administrative boundaries, for example through building codes and the choice of construction materials. The effectiveness depends on cooperation and coordination with national and sub-national governments, industry, and civil society, and whether cities have adequate capacity to plan and implement mitigation strategies.
For cities, three broad mitigation strategies are found to be effective:
reducing or changing energy and material use towards more sustainable production and consumption
electrification in combination with switching to low-emission energy sources
enhancing carbon uptake and storage in the urban environment, for example through bio-based building materials, permeable surfaces, green roofs, trees, green spaces, rivers, ponds and lakes.
Rapidly growing cities can avoid future emissions by co-locating jobs and housing to achieve compact urban form, and by leapfrogging or transitioning to low-emissions technologies. New and emerging cities will have significant infrastructure development needs to achieve high quality of life, which can be met through energy efficient infrastructures and services, and people-centred urban design.
Effective policy packages would be comprehensive in coverage, harnessed to a clear vision for change, balanced across objectives, aligned with specific technology and system needs, consistent in terms of design and tailored to national circumstances. They are better able to realise synergies and avoid trade-offs across climate and development objectives.
Examples include: emissions reductions from buildings through a mix of efficiency targets, building codes, appliance performance standards, information provision, carbon pricing, finance and technical assistance; and industrial GHG emissions reductions through innovation support, market creation and capacity building.
4. Retrofitting existing building is a way to make big strides quickly
Strategies for established cities to achieve large GHG emissions savings include efficiently improving, repurposing or retrofitting the building stock, targeted infilling, and supporting nonmotorized and public transport.
In modelled global scenarios, existing retrofitted buildings and buildings yet to be built, are projected to approach net zero GHG emissions in 2050 if policy packages, which combine ambitious sufficiency, efficiency, and renewable energy measures, are effectively implemented and barriers to decarbonisation are removed. Low ambitious policies increase the risk of lock-in buildings in carbon for decades.
“Well-designed and effectively implemented mitigation interventions, in both new and existing retrofitted buildings, have significant potential to contribute to achieving sustainable development goals in all regions while adapting buildings to future climate.”
Integrated design approaches to the construction and retrofit of buildings have led to increasing examples of zero energy or zero carbon buildings in several regions. However, the low renovation rates and low ambition of retrofitted buildings have hindered the decrease of emissions.
Mitigation interventions include:
At the design stage: buildings typology, form, and multi-functionality to allow for adjusting the size of buildings to the evolving needs of their users and repurposing unused existing buildings to avoid using GHG-intensive materials and additional land.
At the construction stage: low-emission construction materials, highly efficient building envelope and the integration of renewable energy solutions.
At the use stage: highly efficient appliances and equipment, the optimisation of the use of buildings and the supply with low-emission energy sources.
At the disposal stage: recycling and re-using construction materials.
By 2050, bottom-up studies show that up to 61% of global building emissions could be mitigated. Sufficiency policies that avoid the demand for energy and materials contribute 10% to this potential, energy efficiency policies contribute 42%, and renewable energy policies 9%. The largest share of the mitigation potential of new buildings is available in developing countries.
“In developed countries, the highest mitigation potential is within the retrofit of existing buildings.”
The 2020-2030 decade is critical for accelerating the learning of know-how, building the technical and institutional capacity, setting the appropriate governance structures, ensuring the flow of finance, and in developing the skills needed to fully capture the mitigation potential of buildings.