Methane (CH4) is the second most important greenhouse gas. It is emitted into the atmosphere by natural and anthropogenic sources and removed primarily by the reaction with hydroxyl radical. Its atmospheric concentration has been rapidly rising since the beginning of Industrial Revolution. In the three recent decades CH4 growth rate has shown variable behaviour: until the end of twentieth century it has been slowing down, during 2000-2008 atmospheric concentration has stabilized, and after 2008 it's started to rise again. No significant changes were observed in the CH4 removal processes. Therefore, variability in the CH4 atmospheric concentration is mainly attributed to changes in surface emissions. While global emissions are known to within uncertainty of 15%, regional emissions are largely uncertain. I apply inverse modelling methods where I use satellite and ground-based observations and Chemistry Transport Models in order to improve estimates of CH4 regional emissions. In this talk, I will present the current knowledge about CH4 sources. I will discuss observational datasets and Transport Models that I am using in the inverse modelling. Finally, I will show some results of the inversion studies.