Actually, you can consider the low mixing ratio of H2 to be a result of reconciling several ideas we've been discussing here. H2 overwhelmingly escapes due to its low mass, and any H's that have formed OH- and bonded to N's or C's are heavier than the dominant species, N2, so those molecules essentially precipitate/sequester, via various mechanisms. And of course there's OH- bonding to H+ to yield water, and due to H2O still having a significant molecular dipole moment, it stays rather low in the atmosphere. The mixing ratio of H2 would be even lower if we weren't constantly receiving a more or less steady supply H+ ions from the solar wind. francopoli, am I thinking about this correctly? We are approaching a rather technical discussion :).

So to sum it up, carbon is the devil, trees can kinda kill the devil, and mankind is winning the war against trees. Right now I'm imagining what type of market and climate conditions would have companies launching carbon sinks into space for a net profit via carbon credits. Wooooo, what a wild Friday night!!