Theatre-wide food shortages, what should I do?

[BraselC5048]

I just discovered that I have a flashing "0.0% (predicted)" food shortages in nearly every region in the Americas. (I own everything except Michigan (Iquories protectorate), Huron territory, and territories waay out in the wilderness.) Did Krakatoa decide to go boom, or what? Every town in the Americas is developed, it's late game, if that matters. What am I supposed to do to fix the problem? I could cut lower class taxes to nothing theatre-wide and stay well in the black with more money then I can spend, but I don't want to resort to that. Nearly every region already has fully upgraded to Great Estates and I've researched most, if not all, farming technologies, so I'm at a loss for what to do.

[poa]

if every town is developed already, then there's absolutely NO reason to promote population growth,
rather instead increase low class population tax to squeeze out more money, if happiness allow it