GHG = green house gas, Jon?
I think that the production of commercial fertilizers uses a lot of energy, which often leads to green house gases (electric plants that burn coal, for example), I would think. But I didn't hear the interview, so don't know what she was talking about, of course.
I have wondered about using organic hops that come from New Zealand or other far-away lands. The carbon foot-print of shipping is a serious concern, perhaps outweighing the concern for using certified organic hops. That's why its been great that in the last two years there seems to be more organic hop growers here in the USA. Glen Fuller in Colorado is great to work with http://www.coloradoorganichops.com/