Breaking Down SBTi Carbon Benchmarks for Buildings (aka “how much upfront carbon is ok?”)

The Science Based Targets initiative (SBTi) is an organization focusing on doing science-based research which guides industries on how to align to a climate-neutral economy.

SBTi recently published a document for the project known as “A 1.5˚C pathway for the global buildings sector’s embodied emissions”, which ran from November 2022 to June 2023 and was performed by Ramboll with the support from Sweco.

This report showcases the methodology used for the development of the SBTi Carbon Benchmarks for buildings pathways which are aligned with a 1.5˚C climate change trajectory.

The SBTi Carbon Benchmarks for buildings methodology involves seven key steps:

1. Understanding Embodied Emissions:
   Embodied emissions are the upstream emissions from sourcing, producing construction materials, and emissions from transport to construction sites and demolition. They represent a significant portion of building-related emissions.
2. Setting Science-Based Targets:
   SBTi provides a framework for setting targets that align with a 1.5°C climate change trajectory. These targets help in reducing embodied emissions in the construction sector.
3. Developing Embodied Emissions Pathways:
   This includes creating a global decarbonization pathway for building typologies per square meter. It involves data collection and projection of future activities in the global building stock, including new construction and renovation rates.
4. Attribution Principles for Downscaling:
   This step involves defining how the global carbon budget is divided among different building typologies, balancing equity and efficiency.
5. Aligning with SBTi Fundamentals:
   The process aligns with SBTi’s Sectoral Decarbonization Approach (SDA) methodology, considering both absolute and emission intensity targets.
6. Emission Scope and Renovation vs. New Construction:
   The methodology differentiates between emissions from new constructions and renovations, focusing more on upfront embodied emissions.
7. Application of Reduction Pathways:
   Applying a specific reduction pathway to building typologies based on their emission contributions and future projections.

This methodology aims to establish a scientifically sound, equitable, and practical approach to reducing embodied emissions in the building sector, contributing significantly to climate change mitigation.

Table 6.1 from the SBTi Embodied-carbon-pathway-development-description report, showing the upfront embodied GHG emission intensities for various building typologies from 2025 to 2050 (measured in kg CO2-eq/m2):

The share of the global GHG budget that can be attributed to the building construction also includes renovation activities. The share, therefore, needs to be corrected to take this into account. Currently, the global renovation rate is about 1% based on the IEA’s net zero scenario for limiting global warming to 1.5°C (IEA, NZE scenario).

If this value is applied to the total building stock, then about 2,400 million m2 were renovated in 2020, whilst approximately 7,300 million new m2 were constructed. This implied that, in total, about 9,700 million m2 were renovated or added to the building stock in 2020. Therefore, in 2020 renovation accounted for about 25% of the total area that was either renovated or added as new buildings. The share of the total area that is either renovated or added as new buildings is projected to increase in the future as renovation rates on global scale need to increase from 1% to 2.5%. These projections are based on the IEA’s net zero scenario for limiting global warming to 1.5°C (IEA, NZE scenario).

The GHG emissions per m2 of renovation projects are about 50% lower than the upfront emissions related to new construction. This is based on the few available studies 16 and complemented with expert knowledge from previous LCA studies comparing the impacts of renovation with impacts from the construction of new buildings. Hence, 12.5% of the budget for buildings is reserved for renovation and 87.5% is kept for construction of new buildings. This number is aligned with current efforts to model the EU building stock, including both renovations and new construction. Therefore, the final share of the global GHG emission share that can be attributed to buildings 17 in 2020 amounts to the values showed in the table below. These shares evolve over time as the renovation rate needs to increase from 1% to 2.5%, therefore the share set aside for renovation increases.

Benchmarks play a pivotal role in the climate transition, acting as vital navigational tools guiding us towards a more sustainable and environmentally conscious future. In the context of global efforts to mitigate climate change, benchmarks offer clear, quantifiable targets that organizations, industries, and governments can aim for, providing a roadmap for reducing greenhouse gas emissions and other environmental impacts.

The significance of benchmarks in the climate transition lies in their ability to translate abstract goals into concrete, actionable steps. For instance, by setting specific targets for reducing emissions in the construction sector, benchmarks like those developed by the SBTi Carbon Benchmarks for buildings project make it possible for businesses and policymakers to understand exactly what is required of them to align with global efforts to limit warming to 1.5°C above pre-industrial levels.

At 2050 Materials, we expanded on SBTi’s work to breakdown the benchmarks into specific building components, and to give indications of emissions targets per unit of conventional material. If you would like to see the early results of this research, reach out!

Furthermore, benchmarks serve as a standard for measuring progress. They offer a means to assess how effectively different sectors and organizations are moving towards their sustainability goals. This is crucial for accountability and transparency, as it allows stakeholders, including investors, customers, and the public, to see which entities are genuinely contributing to the climate transition and which are falling behind.

In addition, benchmarks foster innovation and competition. As industries strive to meet or exceed these standards, they are often pushed to innovate new technologies and practices. This drive towards innovation not only helps in meeting current targets but also in setting more ambitious goals in the future, thereby accelerating the pace of environmental improvement.

Lastly, benchmarks play a role in unifying efforts across different sectors and geographies. Climate change is a global issue that requires coordinated action. By providing common targets, benchmarks help align the actions of diverse stakeholders, ensuring that efforts are mutually reinforcing and more impactful.