Architects and design professionals have a unique and critical role to play. We directly shape and influence the built environment worldwide. We are the one industry across all political and geographic boundaries with the agency to affect global emissions immediately. In other words, we can decide to design and build to zero carbon today.

Building operations alone account for about 40% of total global CO₂ emissions; factor in interiors, sitework, landscapes, cityscapes, and infrastructure, and that percentage is much more. If the world is to meet the 1.5°C carbon budget set in the 2015 Paris Agreement, we must provide the necessary leadership and reduce CO₂ emissions in the entire built environment by 65% by 2030 and reach zero carbon by 2040.

How difficult is designing to zero carbon? Not difficult at all, particularly with the resources and technologies available. Here are the three steps to zero carbon.

Zero Carbon in Three Steps

1. Design to the Latest Codes and Standards

Design efficient buildings that use little energy to operate by meeting current energy standards and codes (ASHRAE 90.1-2019 and the 2021 International Energy Conservation Code), their equivalent, or better.

Local building energy codes set minimum energy efficiency requirements. They do not prevent architects, engineers, and building sector professionals from designing to current code standards—or from going above and beyond.

Buildings designed to current standards have several advantages. Studies show that they are cost effective and reduce occupant energy burdens. Furthermore, they can be designed with ready-to-use energy modeling compliance tools, checklists, and trade-off options, such as the U.S. Department of Energy’s COMcheck and REScheck. Architects in more than 170 countries, including many developing countries, can use EDGE’s free software to pinpoint least-cost options and calculate utility savings, payback periods, and a building’s carbon footprint.

2. Design for All-Electric and Renewables

Design all new buildings, major renovations, and developments to use no on-site fossil fuels—gas, oil, or propane—and to be 100% powered by on-site and/or new off-site renewable energy. The health, economic, and environmental benefits of all-electric buildings are well documented.

Burning fossil fuels directly in buildings accounts for 5.4% of worldwide greenhouse gas emissions and 35% percent of all domestic building-sector CO₂ emissions. To meet the 1.5°C carbon budget, buildings must operate on only electricity supplied by on-site and/or new off-site renewable energy (see the Zero Code and 2021 IECC Zero Code Appendix). This will further lay the groundwork for new renewables to decarbonize the power sector and, in turn, the existing building stock.

3. Zero Out Embodied Carbon

While steps 1 and 2 will produce zero-carbon building operations, we must also confront the embodied carbon of building construction and materials if we hope to phase out CO₂ emissions by 2040. Architects, engineers, and planners can minimize the embodied carbon emissions from all new buildings, major renovations, infrastructure, and construction by adopting the following three tactics:

• Reuse. Repurpose and upgrade urban areas and existing buildings instead of constructing new infrastructure; use local and recycled materials when available; and design buildings for deconstruction.
• Reduce. Infill and densify urban areas to utilize existing infrastructure; reduce material use by optimizing structural systems; and specify low- to zero-carbon materials using comparative tools, such as the Embodied Carbon in Construction Calculator.
• Sequester. Use mass timber and glue- or cross-laminated wood from existing sustainably managed forests; use bamboo structural members and panels if available; specify materials that sequester CO₂ in their manufacture or application; and plan and design carbon-sequestering sites, parks, and urban landscapes.

Twenty years ago, when I founded Architecture 2030 and issued the 2030 Challenge, achieving zero carbon buildings seemed a distant aspiration. Today, thanks to the creativity and ingenuity of the global design and construction community, we have the knowledge, standards, tools, and technologies on hand to achieve zero carbon buildings in all climates, worldwide.

We have an extraordinary opportunity to be leaders in solving the climate crisis. This is the ultimate design project. This is our legacy.