Fascinating new paper in Nature about improving our estimate of fossil methane sources. It turns out our estimates of how much methane comes from natural fossil leaks (seepage, mud volcanoes, etc.) might be much lower than we thought. nature.com/articles/s4158… 1/4
If this is the case, it would mean about 22% more anthropogenic fossil CH4 emissions than we previously thought. The interesting question (which the paper doesn't really go into) is how this revision changes our estimates of fossil CH4 emissions over the past few decades. 2/4
Presumably natural fossil leaks are assumed to be fairly static, would reallocating them to anthropogenic fossil emissions change our estimate of whether fossil or agricultural CH4 has driven the rise in CH4 over the past two decades? 3/4
Current estimates (e.g. from the @gcarbonproject Global Methane Budget) suggest that around half the increase in atmospheric CH4 in recent decades is from agg and half is from fossil fuel use (though mostly in Asia and Africa). Will be interesting to see if this changes. 4/4
