By now, architects are familiar with the often cited statistic: the building sector is responsible for nearly 40 percent of the world’s carbon emissions. They understand the role of energy efficiency in reducing fossil-fuel use and tackling climate change. But many are just waking up to the importance of the emissions associated with manufacturing materials and the construction process, or “embodied carbon.” According to the United Nations Environment Programme, it makes up 11 percent of global greenhouse-gas emissions. And, if construction continues at its current pace, in 30 years embodied and operating carbon emissions will be roughly equal.

Experts call the problem urgent. “We are running out of time,” says Victoria Burrows, the director of the Advancing Net Zero project of the World Green Building Council. “But we have an opportunity to act now.” Burrows is one of the authors of the report Bringing Embodied Carbon Upfront. The document, released in late September, advocates for changes in international policy and local regulations, and discusses the need to decarbonize the materials-and- construction supply chain. It provides a timeline, with the ultimate goal of reaching net zero embodied carbon for all new buildings and renovations by 2050. By that year, all buildings, including existing buildings, should also be operationally net zero. “We’ve provided a roadmap,” says Burrows.