Global anthropogenic CH4 emissions from 1970 to 2018: Gravity movement and decoupling evolution

In recent years, the growth rate of global non-CO2 greenhouse gas (GHG) emissions has exceeded carbon dioxide (CO2) emissions, among which methane (CH4) emissions gradually attracted increasing attention. Compared with CO2 emissions, the sources of CH4 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 CH4 emissions from 1970 to 2018. The results showed that the overall gravity center of global CH4 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 CH4 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 CH4 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 CH4 emission mitigation worldwide.