The potential of emerging bio-based products to reduce environmental impacts

Many countries worldwide stimulate the development of a bio-based economy to mitigate climate change and to lower their dependency on fossil-based resources. At the European level, the Bio-Economy Strategy was developed to guide Europe towards a sustainable bio-based economy, which was reinforced in the European Green Deal for achieving climate neutrality by 2050. New bio-based products may improve environmental sustainability compared to their fossil counterparts. However, a comprehensive meta-analysis on the environmental consequences of bio-based products compared to their fossil counterparts has not yet been performed. Existing reviews tend to focus on specific domains such as bioplastics, biochemicals, or bioadhesives and often question claims of reduced impacts or show large variability and trade-offs. Ensuring that bio-based products contribute to a sustainable economy requires comprehensive environmental assessments at an early stage of their development, considering the entire value chain from feedstock sourcing and manufacturing to use and disposal. Prospective life cycle assessment (LCA) is suitable for emerging products and technologies (below TRL 9) modeled to a future, more mature state. Yet, results of prospective LCAs vary strongly due to differences in biomass feedstock, technology, methodological challenges, and biogenic carbon accounting. This study addresses these gaps by systematically comparing environmental footprints of emerging bio-based products to fossil counterparts and identifying where and how environmental benefits and trade-offs occur.

Prior literature includes domain-specific reviews and assessments: reviews on bioplastics question reduced environmental impacts, while reviews on biochemicals and bioadhesives show large variation in climate impacts and trade-offs related to land use change and nutrient emissions. Studies highlight methodological challenges in prospective LCA and differences in biogenic carbon accounting, leading to inconsistent conclusions. There is also recognition that land-use change (LUC) emissions can be substantial but are inconsistently included and methodologically heterogeneous across studies.

The study conducts a systematic comparison of 98 emerging bio-based products against their fossil counterparts using data from 130 prospective LCA studies. Environmental impacts analyzed include greenhouse gas (GHG) footprints and other midpoint categories: non-renewable energy use (NREU), acidification, eutrophication, ozone depletion, and photochemical ozone formation. To enable comparability, system boundaries, functional units, end-of-life, and biogenic carbon accounting were harmonized across studies. The analysis interprets results using response ratios (RR = ln(X_B/X_F)), where X_B and X_F are the impacts of the bio-based and fossil products, respectively; RR < 0 indicates lower impacts for bio-based products. Random-effects and mixed-effects models were applied to estimate average RRs while accounting for non-independence (multiple footprints per study or product). Subgroup analyses evaluated differences by product category (e.g., biorefinery products, biochemicals, biopolymers, bioadhesives, biocomposites, biofibers), biomass feedstock category (first- and second-generation pure feedstocks, agricultural and forestry residues, waste streams, third-generation), and technology readiness level (TRL groups upscaled to TRL 9). Data extraction followed a structured process: literature searches in Scopus and Web of Science (March 2023) using comprehensive search strings yielded 1349 studies (1978–2023). After excluding biofuel-focused studies and applying inclusion criteria—(1) prospective LCA of emerging technology/material with TRL < 9 modeled to mature state; (2) bio-based product comparable to a fossil ‘drop-in’ or functional equivalent—130 studies were retained. Harmonization assumptions included: treating biogenic CO2 as carbon-neutral due to short rotation periods and short-lived products; extending cradle-to-gate studies to cradle-to-grave by modeling end-of-life incineration based on product chemical structure to ensure consistent accounting of embodied carbon release. Upscaling methods reported included process simulation data, adapted data from patents/reports, analogs from large-scale processes, and linear extrapolation. Statistical analysis used linear mixed-effects models to estimate predicted mean RRs and 95% confidence intervals across categories, and omnibus F-tests assessed subgroup differences.

• On average, emerging bio-based products have 45% lower GHG footprints than fossil counterparts (95% CI: -52% to -37%). The range spans from a 294% higher GHG footprint for certain lignin bioadhesives to a 94% lower footprint for wood fiber biocomposites (n=1). None of the products reach net-zero GHG emissions.
• By product category, average GHG reductions range from 19% (95% CI: -52% to +35%) for bioadhesives to 73% (95% CI: -84% to -54%; n=19) for biorefinery products. Category did not significantly explain variation (omnibus F: 2.13; p=0.07), though biorefinery products show notable potential.
• A microalgae-based adhesive exhibited a GHG footprint ~12 times that of its fossil counterpart due to high energy requirements for cultivation and harvesting.
• Biomass feedstock type did not significantly influence GHG RRs (omnibus F: 1.53; p=0.19). Agricultural and forestry residues tended toward lower GHG emissions, but differences were small; second-generation feedstocks did not systematically outperform first-generation due to varied, sometimes intensive pretreatments.
• Only 13% of studies included LUC-related GHG emissions; these did not show a systematic effect across the dataset, but LUC can be highly variable and important, especially with deforestation.
• Starting TRL did not significantly influence predicted GHG footprints (omnibus F: 2.26; p=0.11); many studies upscaled via process simulation, patents/reports, analog processes, or linear extrapolation. Inclusion of process synergies at commercial scale was inconsistent (about 52%).
• Environmental trade-offs: eutrophication impacts are on average 369% higher (95% CI: +163% to +737%) for bio-based products. Acidification shows a mean increase of 41% (95% CI: -9% to +119%). NREU is on average 37% lower (95% CI: -56% to -10%). Ozone depletion (-28%; 95% CI: -73% to +88%) and photochemical ozone formation (-16%; 95% CI: -57% to +63%) differences were not statistically significant.
• Sectoral implications: replacing petrochemical butadiene and ethylene with bio-based alternatives (average reduction potential ~57%) could reduce up to 19% of the primary chemical industry’s GHG emissions. Replacing plastics with bio-based alternatives (average 38% reduction) could save ~1.3% of total global GHG emissions annually, with greater savings achievable via higher recycling rates, renewable electricity, and process electrification.

The synthesis shows that emerging bio-based products often reduce GHG emissions relative to fossil counterparts, but benefits vary widely and do not achieve net-zero on their own. Results are sensitive to system boundary choices and biogenic carbon accounting. Harmonizing to cradle-to-grave with an incineration scenario revealed that a large share of climate impacts can stem from release of embodied carbon at end-of-life. Real-world recycling, biodegradation, or energy recovery could lower these impacts, underscoring the importance of integrating circularity strategies (recycling, reuse, remanufacturing) into product design and assessment. Product category and feedstock type did not significantly explain variation in GHG benefits, indicating that performance is highly product-specific. Biorefinery integration can enhance reductions through multi-product valorization and energy integration. The lack of significant TRL effects suggests that with appropriate upscaling assumptions, early-stage assessments need not be systematically biased, though standardized upscaling guidelines and inclusion of process synergies are needed. Significant trade-offs in eutrophication and acidification highlight the role of upstream agriculture (notably fertilizer use). Mitigating these requires precision fertilization, renewable fertilizers, and sustainable agricultural practices. LUC-related emissions are a crucial knowledge gap; standardized and harmonized methods to include LUC are necessary, as these can strongly influence bio-based product sustainability. Broader impact categories such as land use, water use, and ecotoxicity—often higher for bio-based products—also affect biodiversity and should be included in future assessments. Overall, bio-based products can contribute to decarbonization, particularly when combined with increased recycling, renewable energy, electrification, and reduced demand.

This study provides a harmonized, meta-analytic comparison of 98 emerging bio-based products versus fossil counterparts across multiple environmental impacts. On average, bio-based products reduce GHG emissions by 45% and NREU by about one-third, but show substantial increases in eutrophication and potential increases in acidification, with wide variability across products. No product achieves net-zero emissions, indicating that bio-based transitions must be complemented by circular strategies (higher recycling, reuse), low-carbon energy, electrified processes, and demand reduction. Future research should: (1) standardize prospective LCA frameworks, including TRL-specific upscaling guidelines and process synergy assumptions; (2) consistently include LUC-related GHG emissions and expand assessment to land and water use and ecotoxicity to capture biodiversity effects; (3) explore integrated biorefinery configurations and agricultural best practices to minimize trade-offs; and (4) align environmental assessments with circularity metrics to better reflect real-world end-of-life and system transitions.

• Only 13% of included studies accounted for land-use change (LUC) emissions; methods and baseline land types varied, limiting systematic conclusions despite potentially large effects.
• End-of-life was standardized to incineration to harmonize cradle-to-grave boundaries, which may overestimate GHG emissions for products that are recycled, biodegradable, or otherwise diverted from incineration.
• Inability to fully standardize technology development assumptions (e.g., process synergies, heat integration, solvent recovery) across studies may introduce heterogeneity in results.
• Product category and feedstock analyses are limited by variability and small sample sizes in some subgroups (e.g., third-generation feedstocks; biorefinery acidification n=4).
• Many environmental categories (land use, water use, ecotoxicity) were sparsely reported, constraining comprehensive impact trade-off analysis and biodiversity implications.