CO2-Meter: A Comprehensive Carbon Footprint Estimator for LLMs on Edge Devices

LLMs have transformed NLP, yet deploying them on edge devices poses great carbon challenges. Prior estimators remain incomplete, neglecting peripheral energy use, distinct prefill/decode behaviors, and SoC design complexity. This paper presents \textit{CO2-Meter}, a unified framework for estimating operational and embodied carbon in LLM edge inference. Contributions include: (1) equation-based peripheral energy models and datasets; (2) a GNN-based predictor with phase-specific LLM energy data; (3) a unit-level embodied carbon model for SoC bottleneck analysis; and (4) validation showing superior accuracy over prior methods. Case studies show \textit{CO2-Meter}'s effectiveness in identifying carbon hotspots and guiding sustainable LLM design on edge platforms. Source code: \url{https://github.com/fuzhenxiao/CO2-Meter}.