European bioeconomy policies stress the need for responsible, efficient feedstock use and timely, comprehensive data on ecosystems and bioeconomic activities. This paper addresses the data gap by: (i) providing holistic county-level (sub-NUTS3) biomass maps for the Republic of Ireland (RoI), covering primary feedstocks (PFs) and secondary feedstocks (SFs, i.e., by-products and waste); (ii) identifying feedstock uses during the study period. In total, 221 feedstocks were mapped: 85 solid PFs (approx. 43 million tonnes dry matter (tDM) nationally) and 136 solid SFs (approx. 6 million tDM nationally), plus 6 liquid PFs (approx. 18 thousand million m3 nationally) and 8 liquid SFs (approx. 39 thousand million m3 nationally). The mapping indicates that environmentally sustainable bio-based value chains (BBVCs) requiring large amounts of solid or liquid SF should prioritise processing sites near major feedstock sources in the southeast and southwest of the RoI. The northwest and east coast have the lowest availability, while the west and midlands have the most variety in quantity and type of feedstock. Counties with abundant feedstocks do not necessarily have high feedstock diversity, except for Cork. Granular sub-NUTS3 mapping of quantities and fate provides a powerful foundation for future feedstock strategies and empowers stakeholders to design innovative BBVCs.

The European Union and United Kingdom (EU+) remain heavily dependent on imported high-protein feed, primarily soybeans, raising concerns about supply resilience and environmental impacts. We assess three legume-based pathways—trade, policy support, and dietary shift—against a 2030 projection horizon, using integrated regional agro-economic, farm-level, and life cycle assessment models. The trade pathway, simulating a complete interruption of protein imports, provides an analytical upper bound for domestic EU+ legume production. It drives substantial land reallocation (+1.5 million ha legume area) but fails to fully replace imports, resulting in higher prices (+150% for soybeans) and reduced livestock output (-3%), exposing systemic vulnerabilities. Farm-level results underscore economic incentives over agroecological potential. Policy support moderately increases legume cultivation with limited market impacts but improves farm-level viability where conditions are favourable. Dietary shifts increase pulse imports (+100%) but reduce global GHG emissions more effectively than supply-side measures. Overall, the results highlight legumes’ potential, limits of self-sufficiency, and the complementary roles of economic incentives and demand-side measures for sustainable and resilient EU+ food systems. Assessing trade disruption, policy support, and dietary shifts shows that expanding legume production in the EU and UK improves resilience but cannot replace protein imports, while demand-side changes deliver greater climate benefits, based on integrated agro‑economic and life cycle modelling.

This paper responds to a comment on our study of national "temperature neutrality" (TN) as a basis for climate policy, using Ireland as a case study. The comment mischaracterises our original analysis in several respects; we correct these mischaracterisations and engage with the substantive arguments raised. We demonstrate that the comment constructs a false dichotomy between national TN and net-zero greenhouse gas emissions (NZ-GHG), overlooking the split-gas compromise pathways explicitly evaluated in our original study. In addition, the EU effort-sharing framework is based on absolute GHG emissions reductions, not temperature contributions, and Ireland's obligations under Regulation (EU) 2018/842 and the Paris Agreement require economy-wide absolute reductions. A national TN approach is therefore incompatible with these existing frameworks. We further show that widespread adoption of national TN would create a proliferation dynamic, a "race to the bottom", in which the mitigation gap left by TN-adopting states increases pressure on remaining states, collectively undermining the EU and global mitigation effort. We also rebut the assertion that GWP100 lacks scientific rigour: it is grounded in the same physical climate modelling as TN-based approaches and benefits from a standardised, internationally accepted accounting protocol. Finally, we highlight the equity implications identified in our original study: national TN grandfathers disproportionately high per-capita agricultural CH4 emissions in Ireland, appropriating emissions space needed by food-insecure developing countries. We conclude that TN is not an effective, fair, transparent, or robust basis for national climate policy.

Animal breeding is a promising strategy to reduce greenhouse gas (GHG) intensities in the beef sector, especially in low-productivity regions like Latin America. Currently, no data on embodied GHG emission for genetic resources exists in life cycle (LC)-based models. A novel biophysical allocation method was developed to derive co-product allocation keys for on-farm burdens of breeding and cow-calf (beef) farms, based on the metabolic energy requirements of reproductive animals at each LC growth stage. GHG intensities were calculated for genetic resources such as semen, embryos, and breeding stock, using high resolution data available from a cattle breeding farm in the Colombian Orinoquia. A novel biophysical approach based on individual animal LC growth stages and metabolizable energy (ME) requirements was developed. Functional units included 1 unit embryo/semen and 1 kg live weight (LW), further distinguished into (i) LWgenetics (determining co-products bred cow, weaned heifer and bull for breeding purposes) and (ii) LWbeef (dependent co-products cull animals and weaned calves). Multifunctionality modeling results were compared with multi-annual cumulative farm GHG emissions and exported LW, economic allocation at animal LC level, along with system expansion and substitution with dependent co-products substituting beef market products. For the first time, genetic resources’ GHG emissions were quantified. GHG intensities for embryos ranged from 0 to 37.5 kg CO2eq unit−1, depending on allocation methods. Results from each allocation method can be used for different purposes, e.g. multi-annual cumulative intensities enable cattle farm benchmarking, while biophysical-based results suit requirements for product environmental footprinting. Including genetic resources as potential beef systems co-products increases accuracy of economic-based intensities, since they can play a major role in farm profitability. The high-quality genetics cattle breed short-cycle Nelore produced LW with up to 2.3 times lower GHG intensities than the dominant regional breed Brahman demonstrating high potential for food security, improved livelihoods, and GHG mitigation in developing regions. This study introduces a novel biophysical allocation method to quantify embodied GHG emissions of genetic resources like embryos and semen and differentiates LW for beef and genetics markets at farm-gate. This method contributes to a more accurate allocation among cattle farms, recognising the critical value and embodied emissions of intermediate genetic resources as well as final outputs. Future research should focus on representative breeding farms to derive region-specific embodied emission factors of genetic resources.

Bioenergy with carbon capture and storage (BECCS) is a key component of pathways to net zero, yet potential interactions with forest carbon dynamics, cascading wood strategies, and progressive decarbonisation and CCS deployment are poorly represented in assessments. Here, using dynamic life cycle assessment, we explore these factors for sawmill residue-derived BECCS value chains over long, yet flexible, time-horizons. BECCS improves the climate performance of bioenergy and consistently delivers long-term global cooling, even in a fully decarbonised economy where substitution benefits cease, provided forest carbon stocks are maintained. Cascading wood use delivers greater near-term cooling via product substitutions compared to direct diversion to bioenergy, and provides temporary carbon storage complementing later deployment of permanent carbon storage via BECCS. Without cascading use, unharvested forests can deliver stronger near-term cooling than direct diversion to bioenergy, even with full BECCS deployment. However, the sink strength diminishes as forests mature, and sequestered carbon may be vulnerable to disturbances such as wildfire. Crossover points highlight the critical role of cascading wood use coupled with BECCS to ensure continuous and enduring cooling effects. Transferring biogenic carbon from forests to geological stores, via multiple uses, is likely to enhance the longevity and resilience of carbon dioxide removal in a rapidly warming world.

Ireland's built environment contributes approximately 37 % to national greenhouse gas (GHG) emissions, with a 3:2 ratio from the residential to non-residential sector. A series of measures, including regulation changes and energy retrofit grants, mean that operational GHG emissions are expected to decrease, whereas the disclosure and cap requirements for upstream GHG emissions, or "embodied carbon" (EC), are still under development. With some nations worldwide already regulating and restricting EC from building projects, a broadly applicable top-down approach is proposed to develop upfront EC caps for new housing construction in Ireland. The topdown approach applies two methods, grandfathering and utility-principle, to allocate national carbon budgets to the upfront stage of new houses. For countries without national carbon budgets, suggestions are given for determining and downscaling the global carbon budget to national levels. In comparison, the generated caps from two methods show similar average values. The grandfathering method suggests 292 and 194 kg CO2eq/m2 for 2024-2025 and 2026-2030, respectively, while 284 and 188 kg CO2eq/m2 are suggested by the utilityprinciple method for the same periods respectively. However, the utility-principle method generates larger uncertainty than the grandfathering method due to a more pronounced response to the 2008 global financial crisis. Following the potential investigation of some strategies to meet the proposed caps, it is found that efficient compliance with the caps necessitates implementation of multiple strategies. Finally, despite some uncertainty, the proposed caps underscore the critical imperative of reducing upfront EC in the Irish residential sector. Current challenges associated with implementing EC mitigation strategies are also highlighted.

Anaerobic digestion (AD) is central to most biorefinery concepts, as an enabler of nutrient cycling and energy recovery. However, the environmental performance of AD-biorefineries remains poorly represented in many life cycle assessment (LCA) studies, owing to complex flows and indirect effects - including diversion of waste streams and multiple pathways of biogas and digestate use. Using a novel, expanded boundary LCA model (LCAD2.0), we systematically demonstrate critical factors influencing the environmental sustainability and nutrient circularity of 150 prospective AD-biorefineries.Critical factors for climate effects are methane yield, the type of energy being substituted, fugitive emissions during biogas upgrading, the counterfactual treatment of waste, and the application of carbon capture and use or storage (CCU/CCS). Critical factors for nutrient cycling include feedstock composition, digestate upcycling, and nitrogen losses during digestate storage. This study provides robust evidence to facilitate the transition towards a climate neutral, circular economy based on AD-biorefineries.

Farmers manage almost 5 billion hectares of land globally, deliver food security and underpin cultural and economic life in rural areas. Farming policies typically prioritise stability and incremental change to mitigate risk. Yet scientific evidence points to a need for transformative change across the land sector to effectively tackle the climate and biodiversity crises. Meanwhile, climate and geopolitical volatility underscore the need for resilient farm systems. Reconciling multifaceted objectives within long-term strategic policymaking for farming and land use is a major challenge, requiring multi-dimensional evidence. Using Ireland’s land sector as an example, we employ strategic foresight combined with quantitative back-casting to explore alternative climate-neutral farming pathways under different future contexts. Bioeconomy and protein diversification pathways score better across sustainability, resilience and risk indicators compared with business as usual (BAU) under uncertain futures represented by shared socioeconomic pathways. These findings help to situate the important, tangible risks associated with climate-neutral transitions against multifaceted risks facing farming stakeholders under BAU.

The urgent need to reduce greenhouse gas emissions has increased interest in legume-based cropping systems. Among the various crop-legume species available, the cool-season species Vicia faba L. (cv. minor; field beans) has attracted significant interest. Assessment of the environmental impact reduction of field beans in a crop-sequence (rotation) is understudied. Data from a long term (2009–2023) field bean experimental platform (the Centre for Sustainable Cropping, CSC; James Hutton Institute, Scotland, UK) were analysed using attributional life cycle assessment (aLCA). This focused on elaborating the impacts of a spring field bean to spring barley (Hordeum vulgare L.) cropping sequence compared with a spring barley to spring barley cropping sequence. Field beans decreased the environmental impact of spring barley production in four of the five two-year crop-sequence periods, with mean impact reductions of approximately 25

The development of a sustainable bioeconomy depends on ensuring that novel bio-based products incur a smaller environmental footprint than the conventional counterparts they replace. Benchmarking the environmental burdens of emerging production routes against established synthetic baselines is critical to avoid "burden shifting". This study presents the first prospective attributional Life Cycle Assessment of the total chemical synthesis of barettin, a bioactive alkaloid originally isolated from the deep-sea marine sponge Geodia barretti-with promising pharmaceutical and antifouling applications. The assessment covers four main reaction steps and incorporates 32 separate inventories for intermediate molecules. Environmental performance was evaluated across sixteen impact categories and four process maturity scenarios: laboratory, scaled-up, scaled-up optimised, and a future decarbonisation scenario. The results indicate a climate change burden ranging from 1884 to 13,970 kg CO2 equivalents per kg of barettin. Organic solvent use (specifically ethyl acetate, dichloromethane, and diethyl ether) was identified as the principal environmental hotspot, driving impacts across almost all categories. The findings demonstrate that transitioning from waste incineration to 95% solvent recycling is the most effective mitigation lever, achieving impact reductions ranging between 32% and 95% across all 16 impact categories assessed. This study establishes a critical environmental baseline against which future bio-based production routes, such as sponge cell culture or wild harvesting, can be rigorously benchmarked. It provides actionable evidence for researchers and decision-makers in the pharmaceutical and bioeconomy sectors to guide the sustainable scale-up of marine-derived metabolites.

This study presents a techno-economic and energy assessment of anaerobic digestion (AD) fed by grass, with water scrubbing and ammonia stripping. Three plant capacities (25,000, 40,000, and 60,000 tonne/year) and three energy supply configurations were evaluated: A (conventional), B (Heat Exchanger Network (HEN)), and C (HEN and Heat Pump (HP)). The optimized HEN achieved full internal heat recovery, while HP supplied up to 63% of heating and 36% of cooling demands. Energy integration reduced utility consumption by 30-35% for Configuration B and by 55-60% for Configuration C. Economic analysis found that breakeven biomethane sale prices ranged from 103 €/MWh (122 $US/MWh) at an ammonia sale price of 200 €/tonne (236 $US/tonne) to 96 €/MWh (114 $US/MWh) at 1000 €/tonne (1183 $US/tonne) for large scale plant and configurations B and C. Overall, thermal recovery enhanced energy efficiency and economic profitability of AD plants. These results point to AD plant configurations that support climate-neutral and circular bioeconomy developments.

Efforts to reduce emissions from livestock systems are often framed as technical or economic challenges, yet farmers' responses to transition policies are shaped by social, cultural, and intergenerational dynamics. Using survey data from 85 Irish beef-suckler farms, this study examines agricultural transition as a social-ecological process structured by cultural embeddedness, perceived economic pressure, and environmental concern. The study combines quantitative and qualitative analyses, including farmer typology clustering, to examine willingness to consider alternative farming practices and transition pathways. While many respondents expressed openness toward diversification and lower-emission practices, substantial heterogeneity existed across the sample. Cultural embeddedness (rho =-0.14) and inheritance status (rho =-0.16) exhibited weak negative associations with willingness to change, while perceived economic pressure showed a weak positive relationship (rho = 0.12), indicating that no single factor exerted a dominant influence on behavioural openness. Cluster analysis identified distinct farmer archetypes, including groups characterised by strong cultural attachment alongside both high and low willingness to transition. The findings indicate that perceptions of agricultural transition are shaped not only by economic viability concerns, but also by identity, intergenerational continuity, and attachment to farming as a way of life. These results suggest that transition policies based solely on economic incentives or emissions reduction targets are unlikely to achieve socially durable outcomes unless they also engage with the cultural and social dimensions embedded within farming systems. The findings have broader relevance for livestock-dependent rural regions internationally where climate mitigation policies intersect with culturally embedded agricultural livelihoods.

Anaerobic digestion (AD) is promoted to decarbonise agriculture while providing renewable energy and improved manure management. This study assesses the technical feasibility and environmental performance of large-and small-scale AD deployment within the agriculture, forestry, and other land use (AFOLU) sector in Ireland to 2050. The national GOBLIN land-balance model was used with detailed feedstock allocation and a life cycle assessment (LCA) model (LCAD 2.0), simulating 160 AFOLU configurations and analysing 14 policy-relevant scenarios in detail. First, only high-ambition AFOLU pathways that substantially reduce beef cattle numbers and reallocate spared grassland to silage and bioenergy crops can reliably supply sufficient feedstock to meet Ireland's 5.7 TWh yr-1 biomethane target; incremental policy pathways offer limited AD expansion and modest emission reductions. Second, large-scale plants deliver the strongest national climate benefits and lowest normalised environmental burdens, whereas widespread deployment of silage-dominated small-scale plants could increase environmental burdens. Third, the net contribution of AD to national climate goals is highly sensitive to how AFOLU transitions, land-sparing strategies, and AD configurations are combined. Overall, optimum AD deployment is contingent on ambitious AFOLU restructuring and carefully targeted technology choices. Land use and AD strategies should be aligned to include targeted incentives for digestion of manure from priority livestock regions, silage or bioenergy crop production in regions spared from livestock and support for high-performing AD configurations. Strategic policy support will be essential to ensure that bio-methane expansion contributes to climate neutrality and circular bioeconomy objectives.

Farmers manage almost 5 billion hectares of land globally, deliver food security and underpin cultural and economic life in rural areas. Farming policies typically prioritise stability and incremental change to mitigate risk. Yet scientific evidence points to a need for transformative change across the land sector to effectively tackle the climate and biodiversity crises. Meanwhile, climate and geopolitical volatility underscore the need for resilient farm systems. Reconciling multifaceted objectives within long-term strategic policymaking for farming and land use is a major challenge, requiring multi-dimensional evidence. Using Ireland’s land sector as an example, we employ structured foresight combined with quantitative back-casting to explore alternative climate-neutral farming pathways under different future contexts. Bioeconomy and diversified protein pathways score better across key sustainability and resilience criteria compared with business as usual (BAU). Well-intentioned policies supporting existing farming practises may underestimate the risks of BAU, and could lock farmers into unsustainable and non-resilient investments.

Global demand for ruminant milk-based products is increasing, contributing to increases in associated environmental impacts. Yet, most efforts to reduce the total environmental impact of dairy production are based on livestock breeding and manipulation of feed and manure systems. Despite the critical need for low-environmental impact breeding, life cycle assessment (LCA) has not been significantly utilized for forage and livestock trait prioritization. By combining LCA and machine learning, we inventory reductions in footprints of grass-fed dairy systems achievable by selective breeding. To measure the environmental impacts of traits and other farm changes, a pasture-centric dairy system representative of Ireland was modelled using the GOBLIN model. Milk produced in ryegrass-based dairy systems in Ireland was associated with environmental impacts of 1.08 kg CO2-eq (global warming), 0.0066 kg PO4-eq (eutrophication), 0.013 kg SO2-eq (acidification), and 1.62 MJ-eq (fossil resource depletion) per kg fat- and protein-corrected milk (FPCM), translating to annual per-hectare loads of 9281.21 kg CO2-eq, 56.75 kg PO4-eq, 108.21 kg SO2-eq, and 14,025.16 MJ-eq, respectively. Using a machine learning model trained on farm-level LCA outputs, complementarities and trade-offs were revealed across 10,000 graduated scenarios analyzed. The XGBoost Regressor achieved an outstanding R2 value of 99 % in estimating the LCA impacts. Principal component analysis and explainable artificial intelligence analyses identified dry matter digestibility, crude protein, and chemical nitrogen use as key drivers of environmental impacts in dairy systems. By optimizing input parameters, the environmental impacts of grass-based milk can be substantially reduced by breeding for 'LCA-designed ideotypes'. The optimal ryegrass ideotype identified for grass-based dairy systems can reduce; (a) global warming potential by 36.7 %, (b) acidification potential by 31 %, (c) eutrophication potential by 29 %, and (d) fossil resource depletion by 11 %, compared to current levels. We conclude that the environmental performance of ryegrass-based dairy systems can be substantially increased by new LCA-designed forage ideotypes. A more systems-based approach to livestock and forage breeding is therefore needed, as a sole focus on low-footprint livestock may overlook critical gains from forage grass improvement.

This study presents an integrated techno-economic and environmental assessment of a biomethane plant in Ireland, processing 50,000 tonnes of food waste annually via anaerobic digestion (AD), according to the National Biomethane Strategy. SuperPro Designer simulation was employed to quantify material and energy flows, supporting a techno-economic analysis (TEA) and life cycle assessment (LCA). The levelized cost of biomethane is estimated at 249 Euro/MWh, 2.9 times the 2019 benchmark, due to high capital (30.3 million Euro) and operational (4.2 million Euro/year) costs driven by inflationary effects caused by external events, such as the war in Ukraine. A biomethane selling price of 111.7 Euro/MWh (household gas price) and gate fees above 69 Euro/tonne are required for breakeven. Unfavourable market conditions would inevitably drive the need for policy supports such as renewable energy incentives or carbon credits to achieve profitability. The LCA shows a net climate benefit of 46 kgCO2eq/tonne. Still, under-estimated methane leaks could offset these gains and cause revenue losses over 100,000 Euro/year. Digestate circularity following the Nitrates Directive presents trade-offs depending on the impact category. This integrated analysis reinforces the economic challenges and environmental potential of biomethane production, offering key insights for advancing Ireland's circular bioeconomy and renewable energy goals.