"The first world war cut Germany off from the rest of the world, so they had to revert to local food. And of course people starved there, and they had a few bad crops, and all the problems that long-distance trade had solved came back with a vengeance." [here]
Right - because after the first world war it was the fact that Germans ate German produced food that was leading to the starvation. No other aggravating circumstances here, huh?
The carbon footprint points that Desrochers makes are stronger. If you think buying locally has value (and I do), you have to understand that it also involves trade-offs.
But I don't think interwar Germany is quite as strong of an argument...