The long and difficult push to decarbonize construction continues to ramp up. More evidence that contractors will be pressured to build in more environmentally responsible ways comes in the form of a new resource from Associated General Contractors (AGC). The trade association recently unveiled "The AGC Playbook on Decarbonization and Carbon Reporting in the Construction Industry," a detailed guide to help contractors devise master plans for reducing the carbon footprint of their projects.
AGC describes the playbook as a contractor-built tool to help contractors assess, track and reduce greenhouse gas emissions for projects they may build, helping the industry to take a leading role in crafting carbon-reduction measures for the industry.
In a news release, AGC says, “This new tool will help firms understand the basics of tracking carbon emissions, including who is responsible for those emissions, how to track them, and what are the best ways to cut them. This is the first document of its kind written by contractors, for contractors, to help them assess the impacts of the projects they are hired to build.”
Those impacts are broad based. From how the project is designed, to the materials used and how they get to the site, to how the work is performed, to how the structure operates after construction, greenhouse gas (GHG) emissions are a byproduct. Added up, they equal a construction project’s total carbon footprint, which in the aggregate amounts to nearly 40% of global carbon emissions by some estimates. That substantial contribution to the globe’s carbon load has industry leaders like AGC looking for possible responses and solutions, and other interests working to better frame the challenge, as seen in the Figure below.
While targeted at general contractors who bear responsibility for overall project outcomes, the AGC initiative necessarily implicates other parties, skilled trade subcontractors and others included. Their contributions — of project materials, components, labor, and work practices — must be factored into comprehensive project carbon footprint calculations. Per the AGC playbook, in projects prioritizing carbon reduction, carbon sources should be precisely identified and responsibility assigned for tracking and mitigating them. Decarbonizing construction, then, will be an intensely collaborative effort.
In their role, subcontractors will have to assess not only their own operations for carbon contribution, but also those of suppliers who provide equipment, components, and materials used in construction. Depending on how they’re formulated, produced, delivered, and installed and their function, those inputs determine a project’s embodied carbon, the sum of GHG emissions tied to processes like raw material extraction, materials manufacturing, transportation/demolition, and disposal. It is distinct from operational carbon, GHG emitted from a project’s ongoing utilization.
Ubiquitous materials like concrete, steel, glass, and wood get the most scrutiny from an embodied carbon analysis, but many others could come into play as construction decarbonization advances. That would put more subcontractors under the microscope from general contractors pursuing greener construction.
In an AGC video briefing on the new playbook, a general contractor executive who helped draft the document, Joe Rozza, chief sustainability officer for Minneapolis-based Ryan Companies, advises construction contractors of all types to put the GHG profile of construction inputs on their radar. Ryan has been working to understand the global warming potential of materials used on its projects and has developed a Top 11, suggesting concern extends beyond the highest volume materials that are the biggest GHG contributors.
“I would encourage companies to understand their products’ role, whether it’s in a high carbon or low carbon footprint and how it helps overall the carbon footprint of a project,” he says. “Those kinds of differentiating factors are going to be important to know going forward. As folks are really trying to show the market that they can decarbonize and help them meet carbon goals, having relationships with subcontractors and materials manufacturers that have really thought this through and are bringing more innovative and better products to market, that’s a great thing to do. Even if it’s not immediately listed as a top priority there’s still a value proposition that’s worth sharing with everybody.”
