I really haven't anything to add to his concise and poignant piece, except to say that overextending your food supply is the classic way empires fall, as detailed in Evan D.G. Fraser and Andrew Rimas' book
A new map of food security risk around the world is, in some ways, depressingly familiar. Sub-saharan Africa leaps out as the place where the most people fear for their next meal, while the rich world has more to fear from obesity. But there's plenty of salutary reminders and fascinating detail, like India's food problems and the vulnerability of Spain.
And it demonstrates the sickening, symbiotic relationship between lack of food and conflict: where one leads, the other follows.
We must start with the worst, in the horn of Africa. In Somalia, Ethiopia and Eritrea, human failings mean a severe drought has tipped millions into famine. It's a textbook case of why things go wrong. War begets poverty, leaving food unaffordable. Devastated infrastructure destroys both food production and the ability to truck in emergency food. The collapse of society means the effects of extreme weather such as drought cannot be dealt with. And the fear of violence turns people into refugees, leaving their livelihoods and social networks behind.
Empires of Food: Feast, Famine, and the Rise and Fall of Civilizations.