Sustainable construction is rapidly evolving, and terms like embodied carbon and operational carbon emissions are becoming central to green building strategies. But have you heard of upfront carbon emissions? This often-overlooked concept plays a pivotal role in achieving low-carbon buildings and advancing net-zero construction goals.

Did you know buildings contribute to 39% of global energy-related CO₂ emissions? That includes 28% from operational energy use like HVAC and lighting and 11% from construction materials and processes.
(Source: WorldGBC)

Let’s explore why reducing upfront carbon emissions is critical in today’s climate action efforts.

What is Upfront Carbon in Green Building?

Upfront carbon refers to the greenhouse gas (GHG) emissions generated from the extraction, manufacturing, transportation, and construction of building materials before the building is occupied.

It’s the initial carbon footprint of a building project, contributing significantly to the environmental impact long before any energy is used by occupants.

Upfront Carbon vs. Embodied vs. Operational Carbon

• Operational Carbon: Emissions from day-to-day energy use (heating, cooling, lighting).
• Embodied Carbon: Total lifecycle emissions materials, transport, construction, use, and demolition.
• Upfront Carbon: A subset of embodied carbon, focused only on emissions from stages A1 to A5 (materials and construction)

Why Upfront Carbon Reduction Matters

• Immediate Climate Impact: Unlike operational emissions, upfront carbon is released immediately, intensifying the climate crisis today, not tomorrow.
• Material Selection Drives Emissions: The choice of low-carbon building materials (like green concrete or recycled steel) can drastically reduce a project’s footprint.
• Design-Phase Decisions: Architects, BIM professionals, and engineers have the most power to reduce emissions early in the design stage.
• Meeting Net-Zero Targets: Without addressing upfront emissions, it’s impossible to meet targets set by the Paris Agreement, RIBA 2030, or LEED Zero.
• Operational Reductions Highlight Upfront Burden: As buildings become more energy-efficient, embodied and upfront emissions become the dominant contributors.

Where Does Upfront Carbon Fit in Life Cycle Assessment (LCA)?

Life Cycle Assessment (LCA) evaluates a building’s environmental impact across its entire lifecycle. It includes:

• A1-A3 (Product Stage): Material extraction and manufacturing
• A4 (Transport): Shipping materials to the site
• A5 (Construction): On-site construction emissions
• B1-B7 (Use Stage): Operational emissions, maintenance, and replacements
• C1-C4 (End-of-Life): Demolition and waste processing
• D (Beyond Lifecycle): Reuse, recycling benefits

Upfront carbon includes modules A1–A5 everything before the building starts operating.

Strategies to Reduce Upfront Carbon in Construction

1. Select Low-Carbon Construction Materials

• Use low-carbon cement, bio-based materials, and recycled steel.
• Source locally to reduce transport-related emissions.
• Use suppliers with verified Environmental Product Declarations (EPDs).

2. Optimize Building Design with BIM

• Utilize Building Information Modeling (BIM) for material efficiency and waste reduction.
• Prioritize modular construction and prefabrication to limit on-site emissions.

3. Apply Circular Economy Principles

• Reuse salvaged materials.
• Design for disassembly and reuse at the end of life.

4. Enhance Supply Chain Sustainability

• Partner with eco-conscious manufacturers and those using renewable energy.
• Track supplier emissions through carbon accounting platforms.

5. Sustainable Construction Practices

• Deploy electric or hybrid machinery to reduce site emissions.
• Reduce waste by implementing lean construction practices.

What is a Typical Building's Upfront Carbon Emissions?

Knowing the carbon intensity per square meter is essential for sustainable design. While it varies by location and materials, studies (including from Australia’s GBCA) provide these benchmarks:

Reference: A Practical Guide to Upfront Carbon Reductions

How to Calculate Upfront Carbon Footprint

To calculate upfront carbon, we can follow these steps:

1. Identify materials and their quantities: Use Material Take-Off (MTO) data from architectural and engineering plans.
2. Gather emission factors: Use databases such as EPDs, ICE (Inventory of Carbon & Energy)
3. Calculate emissions per material:
   
   • Upfront Carbon = Quantity of Material × Emission Factor (kg CO₂e per kg of material)
4. Sum emissions for all materials across Modules A1–A5.
5. Compare with benchmarks: Use industry standards like RIBA 2030 Climate Challenge or LEED/BREEAM ratings to assess performance.

Conclusion

A truly sustainable built environment requires understanding and strategically reducing upfront carbon the 'locked-in' emissions from materials and construction. Their immediate climate impact demands urgent action. As operational emissions decrease, upfront carbon's importance grows, necessitating a shift to low-carbon materials, optimized design, and efficient construction practices.

At Desapex, we are committed to leading this change. We will implement Life Cycle Assessments (LCAs), utilize Environmental Product Declarations (EPDs), and prioritize low-carbon sourcing. We recognize that setting ambitious targets and fostering collaboration are crucial. By focusing on upfront carbon, we aim to build resilient, healthier futures. We are dedicated to leaving a legacy of responsible stewardship, creating buildings that contribute positively to our planet. Our efforts will ensure that we are building more than just structures; we are building a sustainable future. We are dedicated to the reductions of upfront carbon, and will continue to strive to improve our methods."