Objective Shale gas, an unconventional natural gas, is widely regarded as an important transitional fuel in the shift from high-carbon to low-carbon energy sources. In recent years, shale gas has developed rapidly due to its abundant reserves and advancements in extraction technologies. However, the carbon emissions associated with its development and utilization remain highly controversial. Conducting systematic research on the lifecycle carbon emissions of shale gas is essential to comprehensively understand its carbon emission characteristics and its role in achieving the "dual carbon" goals.

Method This study reviewed and summarized the carbon emission characteristics of shale gas based on existing literature, identifying carbon emission sources across its lifecycle stages, including extraction, transportation, and utilization. On this basis, a carbon emission accounting model was constructed, employing both process-based and economic input-output lifecycle assessment methods to evaluate the direct and indirect carbon emissions of shale gas from extraction to final utilization. Furthermore, a comparative analysis was conducted against the lifecycle carbon emissions of coal. In addition, this paper selected three typical chemical industry utilization paths: ammonia synthesis, methanol production, and acetylene production, to clarify the differences in carbon emissions from different paths, and put forward corresponding path selection and optimization suggestions. Based on the analysis of the results, relevant policy recommendations are raised to promote the low-carbon and high-quality development of shale gas.

Result The results indicated that the average lifecycle carbon emissions of shale gas were 135.41 gCO₂e/MJ, ranging from 57.97 to 183.15 gCO₂e/MJ. The utilization phase contributed the highest emissions, accounting for 85.73% of the total, which was followed by the extraction phase, making up 12.47% of the total. Additionally, methane leakage was identified as the primary source of emissions during the extraction phase, contributing approximately 62.01% of the total emissions in this stage.

Conclusion The comparative analysis reveals that the lifecycle carbon emissions of shale gas are significantly lower than those of coal, further confirming the considerable potential of shale gas as a cleaner energy source.