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• The global anthropogenic CH 4 emissions increased from 227.96 tg to 335.58 tg. • The gravity movement of global CH 4 emissions from 1970 to 2018 was depicted. • The spatial and temporal evolution characteristics of CH 4 emissions were analyzed. • The decoupling between economic development and CH 4 emissions was identified. • Practical strategies and implications for CH 4 emission mitigation were proposed. In recent years, the growth rate of global non-CO 2 greenhouse gas (GHG) emissions has exceeded carbon dioxide (CO 2) emissions, among which methane (CH 4) emissions gradually attracted increasing attention. Compared with CO 2 emissions, the sources of CH 4 emissions are more complex. Based on the gravity theory and decoupling analysis, this study aims to explore the long-term time-series characteristics of global anthropogenic CH 4 emissions from 1970 to 2018. The results showed that the overall gravity center of global CH 4 emissions moved towards the east after 2000. The main driving forces could be attributed to the emissions from solid fuel production in China and the oil & gas exploitation in the United States. Specifically, the gravity center of CH 4 emissions from animal husbandry and rice cultivation exhibited a southward shift. Besides, most of the countries and economies were in a decoupling state, driving the gravity center of these countries to the east. Among them, most of the developed countries including Australia, Germany, France, Poland, the United Kingdom, the United States, and Japan showed a strong decoupling state between CH 4 emissions and economic development. However, some developing countries such as Angola, Venezuela, Brazil, Argentina, Libya, and Iran showed a negative decoupling state. By identifying the gravitational movement and decoupling evolution from 1970 to 2018, this study provides practical strategies and implications towards CH 4 emission mitigation worldwide. [Display omitted] [ABSTRACT FROM AUTHOR]

As the world's largest CH 4 emitter, China's CH 4 emissions contribute to climate change more than the amount emitted by many developed countries combined. The rapid growth of China's coal demand has important implications for CH 4 emissions from coal mining or coal mine methane (CMM) emissions. This paper aims to present an overview of bottom-up estimation of China's CMM emissions, including the trend in the last four decades and the limitations of current understanding on CH 4 emissions. Although characterized by significant differences in inventory compilation, statistically, the total CMM emissions rose from 4.64 to 16.41 Tg with a peak of 21.48 Tg from 1980 to 2016. Large discrepancies of inventory results existed in previous studies, which were affected by the coverage of emission sources, emission factors and activity-level data. The disagreements can be largely attributable to the emission factors of underground mining, which contain substantial variances in both spatial and temporal dimensions. To develop more reliable CMM inventories and make targeted mitigation measures, more attention should be paid to the transparency of the estimated results, coal statistics, on-site CMM emission factors, and the emissions from abandoned coal mines. As the leading CH 4 emission source in China, the estimations of CMM emissions urgently need to overcome existing and emerging challenges for compiling a consistent and accurate inventory. Unlabelled Image • We perform an overview of current bottom-up estimation of China's CMM emissions. • CMM emissions over 1980–2016 rose from 4.64 to 16.41 Tg with a peak of 21.48 Tg. • Inventory results were improved along with large discrepancies and disagreements. • We discuss the types of emission source, emission factors and activity-level data. • The limits of current understanding and future research prospects are provided. [ABSTRACT FROM AUTHOR]

• CH 4 emissions in global supply chains during 2000–2012 were tracked. • Consumption-based CH 4 emissions of China/the EU showed an obvious increase/decrease trend in 2000–2012. • Growing amounts of CH 4 emissions were displaced globally via international trade. • The results support supply-chain-wised policy formulation to mitigate CH 4 emissions. Reduction of methane emissions (CH 4) plays an important role in addressing global climate change. Most previous studies have focused on the direct CH 4 emissions of economies, but overlooked the upstream CH 4 emissions along global supply chains induced by the final consumption of economies. Using a global multi-regional input-output analysis, this study aims to explore the evolution of CH 4 emissions embodied in international trade and final consumption in major economies during 2000–2012. The results show that China, the EU, USA, India and Brazil were the top five economies with high volumes of consumption-based CH 4 emissions from 2000 to 2012. In particular, China's consumption-based CH 4 emissions showed an observable growth trend, while the EU, the USA and Japan showed a downward trend. It's estimated that growing amounts of CH 4 emissions (i.e., the volume increase from 77.1 Mt in 2000 to 95.9 Mt in 2012) were transferred globally via international trade, primarily as exports from China, Russia and other large developing economies to consumers in major developed economies. Russia–EU, China–USA and China–EU formed the main bilateral trading pairs of embodied emission flows. Further analysis found that per capita consumption-based CH 4 emissions was closely related to their per capita GDP. Quantifying the CH 4 emissions embodied in trade and final demand of major economies can provide important basis for understanding economy-wide emission drivers to design global and regional CH 4 reduction scheme from a consumer perspective. [ABSTRACT FROM AUTHOR]

Globalization drives anthropogenic methane (CH 4) emissions from upstream to downstream agents through global supply chains. However, previous studies have overlooked the indirect CH 4 emissions enabled by primary suppliers. In this study, we use the Ghosh Multi-Regional Input-Output (MRIO) model and Structural Decomposition Analysis (SDA) to explore the temporal changes in global income-based CH 4 emissions and decompose the socioeconomic drivers. Our results show that global income-based CH 4 emissions increased by 17.21% from 2001 to 2014, with per capita primary inputs and technology being the two key drivers. Specifically, in China and India, income-based CH 4 emissions were mainly from agriculture, and input structure was responsible for restraining the growth in CH 4 emissions from their agricultural activities. On the other hand, service activities dominated the United States and the European Union, and production output structure was accountable for their emission growth related to service activities. To achieve global CH 4 emission mitigation, key sectors of major economies with high income-based CH 4 emissions should optimize their primary input structures, production output structure, and production technologies from the supply-side. It is crucial to reduce enabled CH 4 emissions in emerging economies, particularly in Asia, through the adjustment of primary input activities. [Display omitted] • Per capita primary inputs and technology dominated global CH 4 emission changes. • Income-based emissions decreased in West & Central Europe and the United States. • Agriculture and mining contributed to the high emissions in most emerging economies. • Production output structure accounted for the growth in service-enabled emissions. • Spatial heterogeneity of drivers of income-based CH 4 emissions was discussed. [ABSTRACT FROM AUTHOR]

With the expansion of economic globalization and the growth of international trade, the pulling effect of household consumption to global anthropogenic CH 4 emissions related to production activities is becoming increasingly evident. This paper adopts a new perspective from the household-consumption side to investigate the CH 4 emissions of major economies in 2014 and compares it with the scenario under the final-demand-based perspective by combing the world input-output database and the latest emission data from the UNFCCC and EDGAR v5.0 database. Budgets of CH 4 emissions for 43 economies are established and trade connections & balances among major economies are explored. Results show that consumption-driven economies are allocated more CH 4 emissions in the household-consumption-based accounting (HCBA) framework compared to the final-demand-based accounting (FDBA) framework. The total trade-related transfer of CH 4 emissions is shown to sum up to 19% and 27% of the global total under the HCBA and FDBA frameworks, respectively. The household-consumption-based CH 4 emissions of China, India, Indonesia and Mexico are much lower than their final-demand-based CH 4 emissions, while the converse is true for the United States, Russia, Japan, the United Kingdom and Germany. The new accounting framework provides a new view to understand trade-related CH 4 emissions of major economies and to identify the role of household consumption in global supply chains, offering important implications for greenhouse gas emission mitigation. Unlabelled Image • Latest CH 4 emission inventories for major economies in 2014 are provided. • Household-consumption-based accounting of CH 4 emissions is firstly conducted. • The findings are compared with those under the final-demand-based accounting. • Consumption-oriented economies should take more responsibility for CH 4 reduction. [ABSTRACT FROM AUTHOR]