Toward more comprehensive environmental impact assessments: interlinked global models of LCIA and IAM applicable to this century

Purpose Despite the long-standing demand for research on dynamic lifecycle assessment (LCA) for policymaking, only a few studies have addressed this subject in conjunction with other systems thinking disciplines, such as energy systems models (ESMs) and integrated assessment models (IAMs), which have achieved tremendous success in assessing climate policies in future scenarios. This study explains our methodological advances in the global application of LCA incorporated in IAMs, specifically dose-response functions, models, and future scenarios. Methods We investigate the application of the lifecycle impact assessment method based on endpoint modeling (LIME), developed under the current environmental situation in Japan and globally, to be consistent and compatible with our IAM, which comprises three resource balance models and a simplified climate model. The IAM endogenously generates most inventories consistent with energy scenarios and climate policies linked with the applied LIME. The IAM and LIME are formulated to minimize the discounted sum of supplying the cost of resources over their lifecycles (i.e., from development to end-of-life) to generate time evolutions for the endpoint impacts over this century on a global scale with/without the 2-degree Celsius (2DC) target in a 100% renewable energy scenario. Results and discussion Unlike existing LCA+ESM/IAM studies, which focus on power generation technologies and related (in)direct embedded energy consumption on a lifecycle basis, our model’s expansion to mineral and biomass resources, in addition to energy, has the following novel results: (1) The following inventories in the 2DC target are generally lower than those in business as usual (BAU): temperature and sea level rise, natural resource, and waste discharge; further, SOx emissions are significantly reduced by reducing coal production while increasing forestry. (2) The environmental impacts on the four endpoints of minerals, land use, and land-use change, with the exclusion of energy-related impacts, are significantly larger than those related to energy. (3) Finally, by ensuring inventory reduction, the 2DC target scenario can reduce overall endpoint impacts (by maximum around 20%), except the impacts on biodiversity resulting from forestry expansion to meet predetermined targets. Conclusions Unlike mainstream IAM analyses, we incorporate LIME, instead of energy- and biomass-related resource and climate change impacts alone; our model thus provid