When we apply conventional LCA methodologies to emerging technology, future changes in emission intensities and societal structures are expected to significantly affect assessment outcomes. Future-oriented LCA aims to address this by evaluating emerging technologies under projected future conditions. This involves estimating future foreground data that reflects technological maturity, adapting background data based on future scenarios, and considering future-relevant impact assessment methods. Foreground data often requires expert-based modeling or process simulation. Background data must account for changes in energy systems, material flows, and production structures. Scenario-based approaches help align inventories with possible futures, but new scenarios may be needed when assessed technologies influence societal systems. In impact assessment, the development of future characterization factors remains limited, with most efforts focused on a few impact categories. Currently, no standardized framework exists, and common terminology and methodologies are not yet ready. Further research may contribute to providing flexible, consistent approaches that support custom scenario design, ensure alignment between assumptions and data, and enhance transparency. Developing practical tools and guidance will be key to enabling meaningful and robust assessments under future conditions.

In product LCA, environmental impacts are typically assessed by aligning functional units. This article begins with that principle and explores how introducing a constraint-based perspective can expand the applicability of LCA to broader analyses, including future scenario design and the evaluation of emerging technologies. The author proposes a framework in which functional-unit-based LCA is viewed as a specific case within constraint-based LCA, and has presented this concept at various academic conferences. In this article, the framework is revisited and its practical and research applications are illustrated using net-zero scenario design as an example.

Quantitatively evaluating the effectiveness of CR or CCU technology by LCA has been attracting worldwide attention. However, uncertainties regarding methodologies and conditions remain major challenges. This paper aims to examine the impact of differences in evaluation scope, supply chains, and other conditions on LCA results for CR and CCU. It also discusses the necessity of international guidelines for LCA methodologies.

Facing global crises and threats, including the climate crisis, humanity must make critical choices for the future. This paper outlines a long-term perspective on resource utilization, with a focus on metallic resources, and introduces research aimed at fostering a trend where producers and consumers engaged in the material life cycle adopt long-term innovation strategies. Ten key insights from these studies are discussed.

This paper discusses a scenario design methodology to support system transitions towards a sustainable society. Achieving carbon neutrality and a circular economy requires not only incremental improvements to product life cycles but also a transformation of the entire socio-economic system. To trigger such a system transition, a backcasting scenario approach is often used, where a desirable future vision is envisioned and the pathway to reach the vision is described backward. A distinctive feature of scenario design is its ability to facilitate thought experiments by describing a variety of possible systems in the form of scenarios, free from the constraints of the current system. On the other hand, life cycle evaluation, including LCA, is effective for validating the plausibility of future systems described in the scenarios. Combining scenario design with life cycle evaluation allows for the preliminary evaluation of the feasibility and impacts of proposed designs, making it an effective approach for supporting informed decision-making. However, higher priority in evaluation is placed not on accuracy; rather on identifying the conditions or bottlenecks critical to achieving the goals. Future research topics within the LCA community include exploring combinations of various modeling and evaluation methods for further validating future scenarios, as well as engaging stakeholders through the scenario design and evaluation processes to support practical implementation.

Global environmental crises call for sustainability transitions. This paper reviews the insights from transition research and discusses functions that LCA should fulfill within the context of major socio-technical changes brought about by transition. Six expectations for LCA community are explained: 1) to prepare inventory data and impact coefficients after transition, 2) to re-assess LCA assuming post-transition conditions, 3) to prepare the data of an environmental impact that will draw attention after the realization of a decarbonized society, 4) to establish LCA methodology to promote transitions, 5) to assess the contributions to a transition, and 6) to contribute consensus on transition scenarios to consider.

To achieve carbon neutrality, the chemical industry must transition its carbon sources from fossil-derived materials to those derived from recycling, biomass, and atmospheric CO₂. However, the current availability of biomass resources is insufficient to meet this demand, necessitating enhanced agricultural-industrial collaboration technologies and improvements in both the quality and quantity of recycled resources. Implementing novel resource and conversion technologies is essential for this transformation, and thus, evaluating future technologies becomes critical. This review specifically focuses on cellulose nanofibers (CNF) derived from woody lignocellulosic resources. Using a future-oriented Life Cycle Assessment (LCA) approach, we outline key perspectives on the evaluation of their manufacturing and utilization processes. CNFs, characterized by steel-like strength, low density, and favorable processing attributes, hold significant promise for applications in automotive and electronic devices. Nonetheless, challenges persist, such as regional variations in production processes, difficulties in inventory estimation, and the necessity of establishing effective recycling and recovery systems. Through illustrative case studies, this paper examines methodologies for evaluating these challenges related to future technologies and systematically discusses the implications of future-oriented LCA approaches for the selection of plant-derived materials.

The purpose of this paper is to analyze the disclosed information of carbon footprints of imaging input and/or output equipment such as printers and multifunction devices, and to determine issues for setting functional units that can compare carbon footprints between products. The carbon footprints of the equipment disclosed by the SuMPO EPD are not based on the premise of comparison between products. However, in order to realize carbon neutrality, it is necessary to establish calculation rules for carbon footprints that allow consumers to appropriately compare products. In this study, I analyzed the disclosed information of the SuMPO EPD of 155 equipment disclosed by Brother Industries, Ltd., and presented the current status of carbon footprints of the equipment and a proposal for setting comparable functional units. First, to compare products by functional unit, the lifetime number of printed pages between products should be the same. Second, the carbon footprint per number of printed pages, which is the functional unit, should be calculated by dividing the CO2 emissions over the life cycle of the product by the lifetime number of printed pages. And finally, a note should be added to indicate that the functional unit carbon footprint includes CO2 emissions over the life cycle, not just the use and maintenance stages.