EarthSky had an interesting article this week on the uptick in global methane levels in recent years after “flat-lining” from 1999 to 2006.  The article gives an excellent discussion of where the methane comes from, including natural wetlands and agricultural production, and looks at how it is changing by latitude and how that can help us determine what the causes of the increase are likely to be.  Methane is a potent greenhouse gas, providing much more potential warming per amount than carbon dioxide, so climate scientists are very interested in understanding where it is coming from.  You can read the article here.