Revealing historical peak situation of national CH4 emissions

Much of the existing literature on greenhouse gas peaking focuses on carbon dioxide (CO2) emissions, however there is a lack of research on peaking methane (CH4) emissions, the second-largest greenhouse gas. This paper attempts to determine and classify the peaking status of anthropogenic CH4 emissions in 188 economies over the period 1970–2021 using a trend analysis model and a decoupling model. Fifty-eight economies achieved a peak in total CH4 emissions, and 125 economies achieved a peak in CH4 emissions per capita, showing marked spatial-temporal variation. Emissions generated by the agricultural sector peaked in 84 economies, followed by the energy sector in 63 economies, and the waste sector in 34 economies. Of these, the most volatile was the peak in emissions in the energy sector. There were 45 benign peaking economies and 13 pseudo-peaking economies. The majority of developed economies showed strong decoupling after reaching their peaks. The agricultural sector had the most peak economies which achieved strong decoupling. Among the factors influencing national pathways to peak CH4 emissions, technological progress driving CH4 emissions reductions in benign peak economies is the most important. This study provides targeted strategies for global and national CH4 emissions reduction, particularly given the historical trend and current profile of economies at different levels of emissions evolution.