Methane emissions in major economies: A three-perspective assessment of accounting, decoupling, and driving factors

Reducing methane (CH 4 ) emissions is essential for tackling global warming. Current policies and studies have primarily focused on direct emissions (production-based responsibility) and emissions induced by final demand (consumption-based responsibility), while overlooking the role of primary input suppliers in enabling emissions (income-based responsibility). This study applies the environmentally extended multi-regional input-output model to quantify the income-based CH 4 emissions of major economies during 2000–2014, and compares the results with those derived from production- and consumption-based accounting. On this basis, the Tapio decoupling model and the Logarithmic Mean Divisia Index model are utilized to reveal the decoupling relationship between CH 4 emissions and economic growth across major economies, as well as the key driving factors behind emission changes under the three perspectives. Results show that the income-based accounting approach can identify new key sectors contributing to CH 4 emissions (e.g., wholesale trade sectors in the US and China, and China’s financial services sector), which cannot be captured by production- and consumption-based approaches. The decoupling analysis reveals that the decoupling status varies across accounting perspectives. Achieving sustained strong decoupling requires continuous efforts, and during the study period only the US, the UK and Japan achieved this comprehensively. Decomposition analysis indicates that increases in economic development level constitute the primary driver of CH 4 emissions growth, whereas emission intensity is the dominant mitigating factor. Based on empirical analysis covering the period 2000–2014, this study reveals potential institutional gaps in CH 4 governance and provides directional guidance and methodological insights for future mitigation policy development.