Sabbie A. Miller

Building materials are increasingly positioned as a scalable option for carbon dioxide removal (CDR). Carbon-storing engineered wood products, such as structural mass timber, will be instrumental for CDR. However, system-level perspectives can overlook operational choices that forfeit storage potential. Using stage-resolved life-cycle inventories, scenario-aware uncertainty analysis, and dynamic carbon accounting, we trace carbon flows across mass timber supply chains in the United States, from harvest slash and mill residue to wood products through end-of-life. Across modeled deployment scenarios, we show that management decisions, not technical limits, cut 1.4–2.6 gigatons (Gt) of CO2e storage by 2120, corresponding to roughly one-third of mass timber’s storage potential. Globally, storage losses from these choices could reach 3.8–12 Gt CO2e. We outline a storage-first pathway including slash pyrolysis, diversion of mill residue from bioenergy to wood panel markets, and reuse or pyrolysis at end-of-life. Together, these strategies redirect carbon into value-added, long-lived pools rather than short-lived fates, showing that release timing and supply chain routing choices can matter more than production decarbonization in shaping warming outcomes under mass timber deployment. If implemented, these choices recover forgone storage and aid in developing the built environment as a durable carbon reservoir.

The effective utilization of abundant low-grade clay resources is critical for reducing carbon emissions in the cement industry. Limestone calcined clay cement (LC ³ ) offers a promising pathway, but its performance and carbon reduction potential depend strongly on clay quality and processing conditions. Here, we develop a framework that links clay resource quality, processing strategies, and concrete strength demand to enable resource-efficient deployment of LC ³ . Using 79 concrete mixture datasets and Monte Carlo simulations, we quantify the variability of CO ₂ reduction across different production scenarios. Results show that low-grade clays can be effectively utilized through mix design optimization at low strength levels, while higher strength applications increasingly require purification strategies. Based on global clay resource characteristics, geographically differentiated deployment pathways could achieve up to ∼61% CO ₂ reduction. This work provides practical insights into the large-scale valorization of low-grade resources for low-carbon cement production.

Industrial sectors, especially those with significant global CO ₂ emissions like the cement and concrete industries, are striving to achieve net-zero emissions by 2050. It is anticipated that carbon dioxide removal will be required to meet these goals. Hydrated cement in concrete can react with atmospheric CO ₂ to form carbonate minerals (i.e., carbonation), and in doing so, act as a carbon uptake mechanism. This carbonation process can be accelerated via various engineering interventions, such as crushing concrete after demolition. In this literature review, we examine key parameters, including porosity, exposure conditions, CO ₂ concentration, curing methods, coatings, and supplementary cementitious materials (SCMs), that facilitate CO ₂ uptake in concrete to inform better quantification of life cycle emissions. These findings can inform the feasibility of implementing carbonation as a method for reducing emissions from cement-based materials and identify data limitations that need further study for future modeling efforts. Presently, it has been estimated that 9-17% of concrete production emissions could be re-adsorbed during use and end of life. However, such estimates of uptake have only considered limited data sets, without fully addressing the comingled effects of the parameters impacting carbonation. Further, some carbon uptake modeling efforts may require input values that are not readily available, or may be challenging to repeat, and do not accurately account for carbon fluxes over the life cycle. Findings from this review highlight the importance of development of systematic approaches to assess cradle-to-grave life cycle assessments using dynamic carbon accounting when measuring concrete carbonation.

In the face of two apparently irreconcilable global challenges - housing a growing world population and reducing CO ₂ emissions - we analyse the current, historic and forecast data on the use of construction materials. Today, cement-based materials make up around three quarters of materials used by mass. Historically, we see that cement-based materials use goes through a peak as Gross Domestic Product per capita increases and then falls. This peak of cement use has been particularly pronounced in China, but is now on a downwards path. From now to 2050, three quarters of construction materials demand will be in low- and middle-income countries. We estimate that adopting the best available construction technologies could reduce CO ₂ emissions by about 73% compared to business as usual by 2050. In low- and middle-income countries, the housing and infrastructure needed to achieve the Sustainable Development Goals could be supplied while simultaneously reducing their per capita CO ₂ emissions from structural materials.

Currently, materials production is responsible for over 25% of anthropogenic CO2 emissions. However, due to their long-lived nature and enormous scale of production, some building materials offer a potential means for atmospheric carbon storage. Accurate emissions accounting is key to understanding this potential, yet life-cycle inventory (LCI) databases struggle to keep up with the wide array of novel materials and provide the data to accurately characterize their effect on net greenhouse gas (GHG) emissions and uptake. To this end, we offer a framework for developing LCIs from the ground up using thermodynamic first principles and provide guidance on alternative approaches to characterize material LCIs from limited data when first principles approaches are not feasible. This framework provides a generalizable methodology to develop and compare LCIs of novel material production. To ensure the accuracy of this framework and provide step-by-step examples of its application, we consider the following mineral-based and bio-based building materials: Portland cement, low-carbon steel, gypsum board, and cross-laminated timber from yellow poplar and eastern hemlock, showing good agreement with existing LCIs. This framework is developed with a particular focus on describing GHG emissions and energy consumption of material production but could be extended to other environmental impacts or applications. Grounding initial LCIs in first principles can guide the early-stage design of novel materials and processes to minimize GHG emissions or improve the carbon sequestration potential of critical materials across sectors.

The developed framework provides a generalizable methodology to develop life cycle inventories for novel material production from thermodynamic first principles and essential process parameters.

The frequency, scale, and severity of wildfires are steadily increasing in the Western United States. Sustainable forest management practices through forest thinning could reduce the impact of wildfires and provide lumber for wood-based, long-lived, and low-carbon building materials. This study explores the potential for harvesting biomass in California (CA) to mitigate wildfire risk and provide multi-decade carbon storage in the form of cross-laminated timber (CLT) for use in buildings. First, we assessed biomass resource availability, finding that the total live hardwood and live softwood available in the wildland-urban interfaces (WUIs) across CA sums to 14.1 million metric tons (MMT) and 34.9 MMT, respectively, which contains the equivalent of 90 MMT of atmospheric carbon dioxide. Then, we conducted a life cycle assessment of CLT considering softwood and hardwood sources to provide insights into emissions and energy demand associated with utilization of the wood removed for wildfire risk management. We found that the net life cycle carbon footprint of live hardwood and softwood when including biogenic carbon storage/emissions is 414 and 317 kg CO₂e/m³ CLT, respectively. To incorporate the timing of these emissions and uptake, we have also conducted a cradle-to-grave time-dependent global warming potential (GWP) analysis. The time-adjusted GWP for live hardwood and live softwood is −227 and −104 kg CO₂e/m³ CLT, respectively. In terms of total CLT production potential, 0.03 and 0.005 million m³ CLT can be sourced from live softwood and hardwood, respectively, in WUI on gentle slopes in CA. The resulting insights and approaches from this study are broadly applicable to other forested regions and WUIs across the US and the world, and provide a holistic approach to use forest thinning as a wildfire mitigation strategy in combination with a novel approach for life cycle assessment of building materials with a limited dataset.

There is a rising urgency to decarbonize plastic production given its high carbon footprint and rapid growth in demand. Here, we highlight pathways for carbon uptake and temporary storage (i.e., net-negative greenhouse gas emissions) for plastics on a global scale by 2050. We focus on bio-based plastics and consider potential market replacement, renewable energy integration, and waste management practices. Our analysis reveals that achieving net-negative emissions requires high levels of all three strategies. For example, reaching 60% bio-based plastics still requires 100% renewable energy and 90% recycling, while 40% recycling requires 90% bio-based plastics with 100% renewable energy. Maximizing all three variables could store up to 270 million metric tonnes of carbon dioxide equivalents by 2050. By 2030, annual emissions from plastics could be reduced by 58% compared to current levels by substituting 41% of petroleum-based plastics with bio-based alternatives, transitioning to 100% renewable energy, and recycling 27% of plastics at end-of-life.