By Alexander Passer, Thomas Lützkendorf, Rolf Frischknecht (representing IEA EBC Annex 89)

The built environment contributes 40% of anthropogenic greenhouse gas emissions, is massively affected by the consequences of climate change and can itself be part of the solution. It is a cause, a victim and a solution at the same time and therefore urgently requires actions by COP28 and national governments. A specific GHG budget for national building stocks including a clearly defined reduction pathway towards net zero GHG emissions is needed, in parallel with a legal binding requirement to limit GHG emissions in the life cycle of individual buildings.

Representatives of 198 countries will meet at COP28 to discuss issues of global climate protection and the necessary adaptation to the consequences of recognised climate change and its effects. The important question is whether and to what extent it will be possible to limit global warming to 1.5 C. A large-scale analysis will first determine whether sufficient progress has been made at national levels in reducing greenhouse gas (GHG) emissions to stay within the 1.5 C target.

Numerous countries have formulated targets and developed strategies to reduce and ultimately eliminate national GHG emissions (UN, 2023). The questions arise as to whether some of these targets are too weak and whether even these weak targets can be achieved. The starting point is often a politically defined target year in which climate neutrality is to be achieved at national level. There is often no connection between this political goal (based on an assessment of technical and economic feasibility and social acceptance) and a scientifically determined budget of the remaining GHG emissions that limit warming to 1.5 C. If current trends continue, the remaining budget for limiting global warming will tend to be used up well before the politically defined target year (SRU, 2022).

The announced priorities to be discussed at COP28 will focus on the formulation and fulfilment of national commitments, the financing of damages and the timetable for phasing out fossil fuels. Among other things, the expansion of renewable energy is proposed. These topics seem necessary, but also comparatively abstract. How can all decisions and measures be imbued with questions of recording, evaluating and achieving the necessary reduction of GHG emissions? How can the enforcement of the "polluter pays" principle and the utilisation of opportunities on the demand side be expanded and strengthened? How can the reduction of GHG emissions be monitored, as well as the contribution of sectors, areas of action and/or areas of needs be analyzed in detail?

An international project team under the auspices of the International Energy Agency's Energy in Buildings and Communities Programme (IEA EBC) - Annex 89 'Ways to Implement Net-zero Whole Life Carbon Buildings' is addressing these questions in relation to the construction and real estate industries, national building stocks and specific construction projects. Its focus is on recommendations for action.

The scientists of IEA EBC Annex 89 are convinced that the construction, building and real estate communities can produce solutions that combine climate protection with other basic human needs - including adequate housing. For example, the resource conservation, stewardship and climate protection need to be even more strongly linked. At the building stock level, the aim is to include relevant information in sustainability reporting and portfolio analyses. We recommend that COP28 address the following questions in such a way, that countries from Global North as well as from Global South can adopt resulting recommendations to their context, needs, capabilities and options to act:

Development of key areas of action and needs

In the past, important experience has been gained in defining, analysing and influencing 'lead markets' in important environmental protection issues. It is recommended that such considerations be extended to the consumer and polluter side. Important examples both for the detailed analysis of contributions to GHG emissions and for activities involving the area of action 'Construction, maintenance and operation of buildings' and the area of need 'Construction and housing' as cross-cutting issues (Habert et al, 2020).

Deriving timetables and pathways from GHG budgets

Many countries are pursuing the goal of developing their national building stock towards climate neutrality (UKGBC, 2021). It is necessary to align the target year for achieving this goal with a defined GHG budget for built environment. This entails developing and coordinating a timetable and step-by-step plan for the reduction pathway as a prerequisite for deriving specific GHG requirements for new construction and modernisation projects. The introduction of legally binding maximum target values for GHG-emissions of new constructions and of refurbishments is recommended by 2025 latest with a roadmap to net zero by 2035 at national level (IEA EBC Annex 72, 2022).

Standardising the reporting and evaluating GHG emissions

A prerequisite for strengthening climate protection is the ability to correctly record and assess GHG emissions. One basis for this is the applied life cycle assessment. Efforts to clarify methodological issues and to develop practical instruments should be intensified. The standardisation activities of ISO (see ISO TC 59 SC 17), CEN (see CEN TC 350) and the IEA projects (e.g. IEA EBC Annex 72: 'Assessing Life Cycle Related Environmental Impacts Caused by Buildings') in the field of scientific cooperation can provide a useful starting point. Governments can adopt these terms, definitions and assessment rules as a basis for regulation.

Strengthening GHG emission reporting tools

Positive experiences have been made in the construction and building sector with the introduction of an energy performance certificate. Among other things, it served to improve transparency in the property market by highlighting information about otherwise hidden features. A similar approach can now be taken with the introduction of a building passport. This could (amongst other things) specify and document GHG emissions caused over the life cycle. At the same time, information on material composition - a basis for determining embodied emissions - can be used to build a bridge to the topic of resource efficiency.

Involving stakeholder groups

All stakeholders in construction, building and real estate can make a positive contribution to climate protection. All planning and decision-making processes can address this goal by integrating decision-making processes and improving the exchange of information along the value chains. Questions of compliance with environmental and social standards in the preliminary stages can be linked to the preparation of life cycle assessments. The issue of climate protection should no longer be considered in isolation, but that synergy effects can be harnessed.

References

UN. (2023). Nationally determined contributions under the Paris Agreement - Synthesis report by the secretariat. United Nations. https://unfccc.int/sites/default/files/resource/cma2023_12.pdf?download

SRU. (2022). A justified ceiling to Germany's CO₂ emissions: Questions and answers on its CO₂ budget. German Advisory Council on the Environment. https://www.umweltrat.de/SharedDocs/Downloads/EN/04_Statements/2020_2024/2022_09_The_CO2_budget_approach.pdf?__blob=publicationFile&v=8

Habert, G., Röck, M., Steininger, K., Lupisek, A., Birgisdottir, H., Desing, H., Chandrakumar, C., Pittau, F., Passer, A., Rovers, R., Slavkovic, K., Hollberg, A., Hoxha, E., Jusselme, T., Nault, E., Allacker, K. and Lützkendorf, T. (2020). Carbon budgets for buildings: harmonising temporal, spatial and sectoral dimensions. Buildings and Cities, 1(1), p.429-452. DOI: https://doi.org/10.5334/bc.47

UKGBC. (2021). Net zero whole life carbon roadmap: A pathway for the UK built environment. UK Green Building Council. https://www.ukgbc.org/wp-content/uploads/2021/11/UKGBC-Whole-Life-Carbon-Roadmap-A-Pathway-to-Net-Zero.pdf

IEA EBC Annex 72. (2022). Monte Verità Declaration on a built environment within planetary boundaries: Outcome of IEA EBC Annex 72. https://annex72.iea-ebc.org/Data/Sites/5/media/documents/monteverit%C3%A0declaration_final_signed.pdf

IEA EBC Annex 72 (2023). Assessing Life Cycle Related Environmental Impacts Caused by Buildings.  https://annex72.iea-ebc.org/