Listen to the Context: Towards Faithful Large Language Models for Retrieval Augmented Generation on Climate Questions

David Thulke, Jakob Kemmler, Christian Dugast, Hermann Ney


Abstract
Large language models that use retrieval augmented generation have the potential to unlock valuable knowledge for researchers, policymakers, and the public by making long and technical climate-related documents more accessible. While this approach can help alleviate factual hallucinations by relying on retrieved passages as additional context, its effectiveness depends on whether the model’s output remains faithful to these passages. To address this, we explore the automatic assessment of faithfulness of different models in this setting. We then focus on ClimateGPT, a large language model specialised in climate science, to examine which factors in its instruction fine-tuning impact the model’s faithfulness. By excluding unfaithful subsets of the model’s training data, we develop ClimateGPT Faithful+, which achieves an improvement in faithfulness from 30% to 57% in supported atomic claims according to our automatic metric.
Anthology ID:
2025.climatenlp-1.17
Volume:
Proceedings of the 2nd Workshop on Natural Language Processing Meets Climate Change (ClimateNLP 2025)
Month:
July
Year:
2025
Address:
Bangkok, Thailand
Editors:
Kalyan Dutia, Peter Henderson, Markus Leippold, Christoper Manning, Gaku Morio, Veruska Muccione, Jingwei Ni, Tobias Schimanski, Dominik Stammbach, Alok Singh, Alba (Ruiran) Su, Saeid A. Vaghefi
Venues:
ClimateNLP | WS
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Publisher:
Association for Computational Linguistics
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Pages:
245–259
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URL:
https://preview.aclanthology.org/landing_page/2025.climatenlp-1.17/
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Cite (ACL):
David Thulke, Jakob Kemmler, Christian Dugast, and Hermann Ney. 2025. Listen to the Context: Towards Faithful Large Language Models for Retrieval Augmented Generation on Climate Questions. In Proceedings of the 2nd Workshop on Natural Language Processing Meets Climate Change (ClimateNLP 2025), pages 245–259, Bangkok, Thailand. Association for Computational Linguistics.
Cite (Informal):
Listen to the Context: Towards Faithful Large Language Models for Retrieval Augmented Generation on Climate Questions (Thulke et al., ClimateNLP 2025)
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PDF:
https://preview.aclanthology.org/landing_page/2025.climatenlp-1.17.pdf