Carbon Information Disclosure Quality in China’s Petroleum and Petrochemical Enterprises: An LLM Approach

Global climate governance and corporate low-carbon transition have made carbon information disclosure important for assessing firms’ environmental governance and climate-risk responses. This study develops an industry-specific carbon information disclosure quality (CIDQ) framework for Chinese A-share listed petroleum and petrochemical firms, using 45 firm-year observations from 15 firms during 2022–2024. The framework includes 7 primary, 15 secondary, and 33 tertiary indicators. Disclosure texts were scored by the DeepSeek-V3.2 large language model (LLM) under predefined rule-based criteria, with temperature set to 0. Reliability was assessed against manual scoring of 15 reports, yielding an intraclass correlation coefficient (ICC) of 0.974. The full-sample mean score is 34.02, accounting for only 51.55% of the theoretical maximum of 66, indicating that the overall disclosure level remains relatively low. The annual mean score increased from 29.07 in 2022 to 37.60 in 2024, representing a cumulative rise of 8.53 points, or 29.34%. Substantial inter-firm differences are also observed: Sinopec recorded the highest three-year average score of 52.67, whereas Yunnan Yunwei recorded the lowest at 10.67. This study may provide a methodological reference for structured CIDQ evaluation and disclosure improvement in high-emission industries.