As previously discussed, the built environment sector is responsible for over a quarter of global emissions. The World Green Building Council is a network of over 75 Green Building Councils (GBCs) and industry partners striving to create sustainable and decarbonised built environments.[i] The ‘WorldGBC Advancing Net Zero Status Report 2023’ that was released this July examines the progress that GBCs have made in working towards net zero.
One of the focus areas of the report is the Whole Life Carbon (WLC) Vision. The aim of this vision is to reach net zero whole life carbon in the built environment sector. That is:
“When, in addition to net zero operational carbon, upfront carbon and other embodied carbon across the building lifecycle is reduced to a level that is consistent with reaching net zero at the global or sector level in 1.5°C pathways. Any residual emissions that remain unfeasible to eliminate should be neutralized through carbon removals.”[ii]
Embodied carbon is the greenhouse gas emissions resulting from extracting and processing materials and making them into products and buildings, alongside the emissions associated with transport and work on a construction site. One way to calculate the embodied carbon of a product or asset is through a footprinting measure called a Life Cycle Assessment (LCA). There are three main models in LCA. The cradle-to-grave model examines the product's environmental footprint, starting from the raw material extraction until the waste disposal. The cradle-to-gate model, however, only considers the raw material extraction and the use and transportation of these materials to the factory gate. In terms of the built environment, this model would not consider the delivery of the materials to site, their construction, assembly, maintenance, or disposal. The cradle-to-cradle LCA model is what would be used if the building materials were being recycled and used for another product. This is the LCA model that would be used in a circular economy.
Figure 1: The World GBC’s Whole Life Carbon Vision
Since the last Status report from the World GBC, three new GBC Whole Life Carbon (WLC) roadmaps have been released. These are from Italy (GB Italia), Germany (DGNB), and Croatia (Croatia GBC). The total number of released or developing national roadmaps sits at 22.[iii] The World GBC has also released an EU Policy Whole Life Carbon Roadmap.[iv] This plan is meant to make it easier for EU policymakers and those working in the built environment sector to work together to decarbonise buildings and construction by 2050.
The report also indicates an up-to-date count of the number of signatories that the World GBC Net Zero Carbon Buildings Commitment has. The Commitment builds off the WLC Vision and requires that by 2030:
· Existing buildings reduce their energy consumption and eliminate emissions from energy and refrigerants, removing fossil fuel use as fast as practicable (where applicable). Where necessary, compensate for residual emissions.
· New developments and major renovations are built to be highly efficient, powered by renewables, with a maximum reduction in embodied carbon and compensation of all residual upfront emissions[v].
Figure 2: Impact of the Net Zero Carbon Buildings Commitment
140 of these signatories are businesses and organisations. When companies and organisations create their own bespoke decarbonisation roadmaps to help their buildings reach net zero, targets should be set using the metrics of energy efficiency, onsite renewable energy, offsite renewable energy, maximising the reduction of embodied carbon, and carbon offsets. The signatories also advocate for the uptake of zero-carbon buildings through tenant support on decarbonisation, sustainability services for clients, supplier engagement, advocacy through membership and partnership, and advocacy communications.
A key message in the report is that the solutions already exist to create sustainable and decarbonised built environments. Where there are problems, there are solutions. The report outlines eight key problems with net zero:
· 1. Retrofitting existing buildings is often said to be more difficult than building new ones.
· 2. We need to be able to measure emissions before tackling them.
· 3. Nationally Determined Contributions (NDCs) will be needed by each national government to cut emissions. However, there are gaps in some countries’ NDCs, and more needs to be done to connect the NDCs to concrete action on the ground[vi].
· 4. Despite contributing to around 11% of all global carbon emissions, embodied carbon has historically been overlooked[vii].
· 5. To deliver net zero buildings at scale, there needs to be the right finance mechanisms in place.
· 6. Electrification is important to decarbonise the built environment, but this puts increased pressure on the energy grid.
· 7. Poor quality and unverified offset credits create new problems.
· 8. There is a lack of consistency in definitions such as ‘net zero’ and ‘carbon neutral’, and this creates difficulties in setting targets and benchmarks across the construction sector.
For each challenge, the report highlights some of the trends and innovations happening in the built environment sector to address the problem. For example, the problem of needing data and measurements to tackle emissions can be partly addressed through EPDs (Environmental Product Declarations). EPDs state a product or material’s environmental performance and impact over its lifetime, meaning they can be used for whole life carbon calculations. Furthermore, Zero Carbon Academy have discussed how government policy can be used to encourage retrofit and renovation of existing buildings.
A lot of the progress in this area is coming from the private sector. WBCSD and Arup have found that it is possible to halve embodied carbon emissions immediately using what is already available[viii]. This has been supported by the ‘Building value by decarbonizing the built environment’ McKinsey report, which highlights how existing technology can reduce over 50% of building emissions by 2050. Case studies of embodied carbon reduction best practices produced by the Low Energy Transformation Initiative (LETI), and the soon-to-be-released building sector-specific guidance on operational and embodied carbon from the Science Based Targets Initiative, are also highlighted as developments that are making headway.
Energy transition, inclusivity, youth, and nature are expected to be some of the focus areas at COP28. The World GBC report positions the building and construction sector as vital in supporting these areas. World GBC, #BuildingToCOP Coalition, and delegates of several GBCs will be collaborating to represent the sector. It is expected that COP28 will build on the successes of the COP27 Buildings Breakthrough (which has a target that near-zero emission and resilient buildings will be the new normal by 2030) and that the Race to Resilience will be featured prominently.
Gemma recently graduated with a degree in International Development. She is currently studying for an MSc in Sustainable Urbanism, which examines urban planning and urban design through a sustainability lens. “I’m passionate about addressing sustainability challenges in a holistic and pragmatic way. Zero Carbon Academy's diverse range of services targets many of the areas that need support if we are to transition to a liveable future. I’m excited to see the impact that the Academy makes.”