+Methane - Surprisingly not from fossil fuels

Some of the potentially runaway methane sources are scary to think about, such as the increased release from the arctic upon thawing of the permafrost and the ice over ancient lakes. I'll try to be more conscientious about reducing my personal methane emissions as well.

 

If someone here is interested in global methane, they would look at both this recent Schaefer et al in Science (no known relation) and Tian et al in Nature. They take different approaches, look at different data, and might finally be arriving at different conclusions.

Before digging into that I'd like to mention that the slowed rate if methane increase 1992-2006 was (at the time) heralded in 'non-mainstream' climate literature as evidence that everything was OK and there were no climate problems. I am unaware of any retractions on that point, with methane increase since returning to the prior upward slope.

Now, methane increase has returned to that increase, and we wonder if the cause is more from Ag, high-latitude soils, or fossil-fuel extraction. At first reading, the first paper above argues in favor of increase from non-fossil-fuel sources. I don't yet see that they have separated Ag. from other biological sources. But they do suggest a combination of ruminants (incl. cattle) and wetland rice to be the source of the increase, as opposed to fossil C.

Cows& rice may have much increased since 2006, or not. I really don't know.

Anyway, as methane is such a good IR absorber, this ought to be examined further.

 

For release sources, don't forget the cold underwater methane ices / hydrates / clathrates. As ocean waters warm, more of this stored stock should melt and release. Not all of this reaches the atmosphere, but I don't know what fraction is retained and consumed in the water.

 

Very recent global methane map from AIRS

A Global View Of Methane - GreenAtom

 

Aside from look-down satellites, we have very poor ways to know marine methane sources. Traditional oceanographic cruises cost a lot. If this is 'a thing', it might be handled more cheaply via long-range big-drone flights. Those can be fitted to do science instead of launching Hellfire missiles.

 

Another new publication in Atmospheric Chemistry and Physics, suggests that (oh maybe 1/3) of the recent methane increase can be attributed to fossil fuel extraction. Based on also measuring ethane increases. That molecule does not arise from biogenic processes.

But they only have a couple of sites, so the situation appears complex. As so often the case eh? Something for everybody. The way they measure ethane is amazingly complex and will not happen at many other places I suppose.