Shouldn't the food production problem and potentially even the entire ecosystem collapse of been solved when they had cheap widespread Astrophage breeders. They are near perfect solor panels with near unlimited energy storage and easy energy transportation.

My first thought was you could use the energy for widespread hydroponics. But I don't think you would even need to do that. I haven't done the math but the potential energy production seems large enough you could just do resistive or Astrophage heating in open fields with grow lights. As solar energy drops off you replace it with energy from what are effectively wastelands. Solar energy from the Majove desert growing crops in the Midwest.

China is also not going to stop producing breeders just because the Sahara is covered. They'll see the potential and start covering the Gobi. Everyone else capable of producing breeders will follow suite.

I think long term global warming might end up being the issue. These breeders have the potential to of being deployed on a large enough scale that the albedo of the Earth might be changed enough to more than offset cooling from the drop in solar energy.