Proportionate Responses: The Case for Small Language Models as Sustainable Expert Climate Policy Annotators

Jetske Bonenkamp, Robbert Biesbroek, Ioannis N. Athanasiadis


Abstract
Tracking progress on climate change adaptation requires systematic and robust annotation of adaptation policies, but manual annotation has become infeasible due to the rapidly growing volume of unstructured documents. Pre-trained language models (LMs) have emerged as promising tools for automating and scaling annotation. However, relatively little is known about their accuracy and quality on complex, free-text annotation tasks. Meanwhile, large LMs (LLMs) are increasingly deployed for large scale text analyses despite their considerable environmental footprint and limited exploration of more sustainable alternatives. By benchmarking model accuracy against human inter-annotator agreement, reviewing perceived annotation quality, and estimating energy and water consumption, we show that fine-tuning small LMs (SLMs) provides a substantially more sustainable alternative to LLMs with only marginal reductions in accuracy and improved perceived annotation quality. Furthermore, we demonstrate the importance of evaluating complex annotation tasks beyond accuracy against human gold standard annotation as ambiguity and human error can obscure meaningful differences in model performance. By reducing the costs of high-quality policy annotation, our approach enables the scalable knowledge extraction needed for tracking progress on adaptation, living evidence syntheses, and evidence-informed policy evaluation.
Anthology ID:
2026.climatenlp-1.21
Volume:
Proceedings of the 3rd Workshop on Natural Language Processing Meets Climate Change (ClimateNLP 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Tobias Schimanski, Aida Usmanova, Gaku Morio, Jingwei Ni, Kalyan Dutia, Seyed Saeid Vaghefi, Dominik Stammbach, Markus Leippold
Venues:
ClimateNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
315–340
Language:
URL:
https://aclanthology.org/2026.climatenlp-1.21/
DOI:
Bibkey:
Cite (ACL):
Jetske Bonenkamp, Robbert Biesbroek, and Ioannis N. Athanasiadis. 2026. Proportionate Responses: The Case for Small Language Models as Sustainable Expert Climate Policy Annotators. In Proceedings of the 3rd Workshop on Natural Language Processing Meets Climate Change (ClimateNLP 2026), pages 315–340, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Proportionate Responses: The Case for Small Language Models as Sustainable Expert Climate Policy Annotators (Bonenkamp et al., ClimateNLP 2026)
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PDF:
https://aclanthology.org/2026.climatenlp-1.21.pdf