21. Initiatives to Report and Reduce Embodied Carbon in North American Buildings

This chapter reviews the efforts in North America on assessing and lowering the embodied carbon in buildings. The Intergovernmental Panel on Climate Change warns that the building sector needs to be zero carbon by 2050. While initiatives such as the American Institute of Architects 2030 Commitment have incentivized the reduction of operational impacts related to the use of buildings, new initiatives such as the Structural Engineers 2050 Commitment emphasize the reduction of embodied impacts related to material extraction, production, transportation to the site, construction, maintenance, and demolition. To assess and lower these impacts, three challenges arise in North America: the inconsistency in available databases and tools, the difficulty of including embodied carbon credits in rating schemes, and the scarcity of benchmarks. First, we review life cycle assessment databases and environmental product declarations available in North America. Then, we present the challenges of life cycle assessment in the Leadership in Energy and Environmental Design (LEED) rating scheme. Finally, the authors propose two benchmarking paradigms initiated in the USA to create a baseline for the embodied carbon of buildings, expressed in carbon dioxide-equivalent emissions normalized by floor area (kgCO₂e/m²).