If only I had a real PHD now, maybe someone would listen to my pleas to subsidize farm biogas, hehey.  It is looking better and better as a central part of ag and energy policy reform.  laughing gas (nitrous oxide0 is no joke when it comes to climate change.

Biodigestion not only takes care of the methane released by manure and fertilizer run off (organic fertilizer a byproduct of biodigestion, tends not to run off, as chemical fertilizer does), but also the nitrous oxide.  With 296 times the GHG effect of CO2.

Methane is 21 times CO2.  This idea that if 5% of our energy came from biogas from waste, that would offset the whole human CO2 production, seems to be fulfilling itself.

Now exactly how much nitrous oxide comes from manure and fertilizer run off?  That's a big potential offset boost!  296x.

"Although 10% of the ocean's drawdown of atmospheric anthropogenic carbon dioxide may result from this atmospheric nitrogen fertilization, leading to a decrease in radiative forcing, up to about two-thirds of this amount may be offset by the increase in N2O emissions."

So two-thirds of the CO2 taken out of the atmosphere by a chemical ag crop like corn is cancelled by increased nitrous oxide emitted from the fertilizer.

That leaves only 1/3 of the CO2 released by burning the corn as ethanol, effectively reabsorbed by the corn.  2/3 of corn ethanol's (falsely claimed) carbon neutrality is gone due to ammonia fertilizer.

Look at that huge release of N20 over the whole of chemical ag.  Equal to 2/3 of the CO2 absorbed in photosynthesis on that crop land.

This makes biodigestion and organic ag an even more effective GHG climate cure.  As good, on the positive GHG canceling side as chemical ag is bad for the GHG balance.