Anthropogenic methane emission is the most important greenhouse gas, after CO₂ emission. However, various aspects of methane emission have not been adequately examined in the existing literature including its persistence, methane emission, which is a measure of the extent to which short-term shocks (resulting from new government initiatives) are able to generate permanent future changes. It is important to determine the persistence of methane emissions. The existence of persistence of methane emissions implies that any temporary shock will have a permanent impact on methane emissions and the methane emission level will not move back to its steady long-term growth path. The persistence of the methane emissions in a group of 36 OECD countries has been examined in this work for the time period 1750–2014 using techniques based on fractional integration. 

This allows us to determine the degree of persistence of the series and the potential presence of trends in the data. Our results indicate that all series are highly persistent, with orders of integration above 1 in the majority of the cases. Linear (positive) trends are observed in approximately half of the cases. One of the implications of these findings is that policies designed for decreasing methane emissions will have a long-term impact in these countries. The methane emission policies include improvement in the equipment employed to generate, store and convey natural gas and oil; changing manure management policies; modifications to animal feeding strategies and introduction of emission controls that capture landfill methane.