All LCA models are wrong. Are some of them useful? Towards open computational LCA in ICT

TL;DR

This paper discusses the importance of rigorous modeling practices in ICT Life Cycle Assessment (LCA) and proposes a framework for open, traceable, and credible LCA models to improve their usefulness.

Contribution

It introduces a set of key requirements and a framework for credible ICT LCA modeling, emphasizing transparency, traceability, and open repositories.

Findings

Current ICT LCA practices often lack rigor and transparency.

Structural challenges hinder reliable LCA modeling in ICT.

The proposed framework aims to enhance credibility and usability of LCA models.

Abstract

Life Cycle Assessment (LCA) is increasingly used to quantify and regulate the environmental impacts of Information and Communication Technology (ICT) systems. Since direct biosphere measurements are complicated to perform, we claim that the environmental impact assessment of ICT relies heavily on models. In this paper, we first revisit the fundamentals of LCA: we emphasize that ICT LCAs effectively form systems of models, and we argue that such systems require an extra-high level of carefulness in construction, calibration, integration, and interpretation. We then document how this level of rigor is challenging to achieve with current practices. This is illustrated with emblematic examples of model misuse and an analysis of structural challenges related to database choice, scope mismatches, opaque aggregation, and model integration. From this analysis, we derive four key requirements for credible ICT LCA: explicit model lineage, clearly defined model scope, end-to-end traceability, and managed non-obsolescence. Finally, we propose a framework that operationalizes these requirements using explicit dependency graphs, an open and versioned LCA-oriented model repository, automatic enforcement of integrity constraints, and a well-defined model taxonomy.