Proposal for an interlinked global model of LCIA and IAM for the water–energy–mineral–land nexus: global case study until 2100 for meeting the 2-degree Celsius scenario

The five-node resource nexus is a recognized framework covering energy, minerals, land, water, and food concurrently. However, most current models lack the scope to cover all the nodes. Furthermore, the absence of a long-term global perspective limits our understanding of future resource interrelations. The current study introduces an integrated assessment model (IAM) designed to fill these resource coverage and temporal gaps. By integrating a water resource model and human health impacts via water supply shortages into our IAM, we successfully capture the interrelations across all five nodes. The model comprehensively covers consequential impacts by resource use, such as climate change, local air pollution, land use and its change, mineral resources, and so forth. The framework utilizes a hybrid approach, integrating four resource-balance models and a Life Cycle Impact Assessment (LCIA) model into a macro-economic structure with social welfare maximization. The study results clarified causal chains that start from a carbon budget, which does not appear in the five-node nexus, to reach land and energy resources. Each chain arrives not only through food but also through bio-resources (biodiversity) and minerals. The chain from food to water resources causes the most significant changes in water. The lifecycle impact assessment model enables us to clarify impacts on human health. We conclude that our modeling approach can address interrelations in all the five-node nexus.