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'Buy Clean' policies have promise, but we first need to know which products are low-carbon

A pallet of concrete blocks.

A pallet of concrete blocks.


Legislators and advocates are increasingly looking to spur demand for low-carbon products, a key step for reducing industrial emissions. In this approach, government purchasing power can help provide a market signal for products with lower embodied carbon (reflecting the impact of all greenhouse gases across extraction, manufacturing and transportation to the purchaser). 

Federal and state efforts have enormous potential, but implementation has proved difficult because key information is often missing. In fact, inadequate data poses a broader challenge and is hampering many efforts to cut carbon.

Data on the carbon content of materials and systems for tracking and transparently reporting information across supply chains are inadequate. There is variation in current rules for reporting, exemptions and standards and how product lifecycles are estimated. These challenges make harmonization of targets difficult. We must address these barriers if we are to identify, label and prioritize low-carbon products.

California’s efforts demonstrate both the potential for demand-side solutions and the challenge of data limitations. The Buy Clean California Act (effective in 2019) requires contractors that bid on infrastructure projects to disclose greenhouse gas (GHG) emissions data for certain materials that they plan to use. These disclosures, called Environmental Product Declarations (EPDs), allow government purchasers to take the embodied carbon of materials into account, in turn using the states’ purchasing power to influence manufacturers to reduce emissions.

Data on the carbon content of materials and systems for tracking and transparently reporting information across supply chains are inadequate.

When U.S. manufacturers quantify the carbon content of subparts, some data are just not available. Data from other regions that require reporting (for example, Europe) could be considered, but the differences in energy systems and policies may introduce additional uncertainty. For example, the California Department of General Services was forced to add 20 percent to the baseline GHG compliance limit for eligible materials to account for uncertainty of data sources.

Other confounding factors include variation in how construction, use and end-of-life stages of products are factored into the EPDs. It doesn’t help that factories are often updated faster than databases, leaving accessible public data behind current practice. New tools such as the Embodied Carbon in Construction Calculator (EC3) aim to address some of these issues. 

Efforts to close the gap

Policymakers are starting to take notice of the data challenges. In Washington, Oregon and Minnesota, legislators planning Buy Clean policies aim to incorporate lessons from California while tailoring bills to fit their states’ specific manufacturing capacity. For example, a study for Washington state recommended the development of a North American lifecycle inventory database, formation of a searchable EPD database, and development of a common benchmark methodology to improve EPDs.

A proposal for a federal Buy Clean program in the Clean Future Act would mitigate some data gaps and standardization issues by creating a National EPD Database. The bill would direct EPA to assist manufacturers to help standardize EPDs and develop both strategic plans for certain vulnerable industries and clear rules for reporting.

Other data challenges

Data challenges arise in numerous areas beyond embodied carbon. Limited data are available for attributing carbon emissions for various parties in supply chains, understanding potential climate impacts and risks, and reallocating capital (such as after a corporate merger, acquisition or divestiture). For example, when companies try to calculate GHG emissions for their products along the supply chain, they can encounter information gaps and different baselines. The share of leading companies reporting GHG emissions has stalled at 60 percent, which leaves large gaps in investor knowledge on carbon risks. At the federal level, a report by the House Select Committee on the Climate Crisis recognized the challenge, noting that "new knowledge infrastructure" including "data gathering and analysis ... will also be crucial in implementing technologies for reducing industrial emissions."

What's needed

Both industry and government will need to take steps to manage carbon information. Collaborative agency research (including by EPA, the Department of Energy (DOE), and the National Institute of Standards and Technology) is necessary to establish nationally recognized processes for measuring, publicly reporting and labeling the carbon content of products or materials sold domestically. Congress should task an agency (such as the Advanced Manufacturing Office at DOE or the Climate Protection Partnerships Division at EPA) with developing and coordinating knowledge infrastructure for energy and carbon across multiple sectors. That lead agency also should be tasked with creating and updating standardized metrics to ensure that information is consistent, verifiable and readily understood.

Both industry and government will need to take steps to manage carbon information.

We suggest that clearinghouses be set up to assemble key data for embodied carbon, emissions and energy inputs. Policy and technology roadmaps from DOE and other agencies presenting pathways to low-carbon manufacturing should be connected to the data clearinghouses, allowing industry to pursue decarbonization with reliable data and clearly defined rules for following carbon along supply chains.

These actions will provide important stepping stones toward presenting embodied-carbon information on product labels that consumers can use to make informed purchasing choices, as they have for more than a quarter century with ENERGY STAR labels ranking energy efficiency. An embodied carbon label will result in greater demand for low-carbon products and a virtuous cycle stimulating low-carbon manufacturing and supply chain choices. But we must act quickly to build a solid knowledge foundation because this will take time to get in place, and the clock is running on our need to respond to climate change.

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