[frank2]

>as in "we can't produce enough food."

US nuclear-war planners in the 1970s or 1980s estimated that there was enough food in silos in the US to feed the survivors for about 3 years. I think they assumed that 50% or 60% of Americans would survive. Usually, most of the grains and beans in those silos would go to feeding livestock, but in an emergency they could be used to keep people alive instead.

So, unless the livestock-feed supply chain has tightened up significantly since the 1970s or 1980s, the US would have about 3 years to get mechanized agriculture back up and running.

Also, ISTR that they estimated that most cars and trucks will survive the attack, but since the electrical systems of automobiles have changed drastically since the 1980s, maybe the US's current inventory of automobiles is a lot more sensitive to electromagnetic pulses. (Cars and trucks are relevant because the US would need some way to transport the grain and beans in silos, most of which are on farms or near farms, to where the people are.)

[waste_monk]

>So, unless the livestock-feed supply chain has tightened up significantly since the 1970s or 1980s, the US would have about 3 years to get mechanized agriculture back up and running.

How would they process into human-usable formats and get it distributed in time in the initial period after the nuclear exchange? Beans are easy, but I would imagine a large proportion of people don't even own a mortar and pestle or other means of improvising a flour mill. It is certainly possible to improvise one, but access to information would also be disrupted immediately after a nuclear war so they couldn't just fire up youtube and watch one of these Primitive Technology videos on how to make a mill. We have forgotten the old ways and I fear many people would simply not be able to cope in a harsher environment without modern conveniences and comforts.

I'm not concerned about food shortages causing human extinction as such. Supermarkets with just-in-time logistics leave no buffer room while the feed is processed, but humans can survive 10's of days or longer without food (as long as they're hydrated, with some variability for body weight, access to vitamin supplements, and so on) and outside of major population centres (which are probably craters by this stage) you'd imagine a good part of the population have decent food stockpiles, and at least some farms would hopefully not be too affected by fallout and could continue producing enough food for at least a small village's worth of people. IIRC you need ~150 genetically healthy breeding pairs of humans to have enough diversity (assuming careful management to avoid inbreeding and so on) to viably repopulate the earth, which should be reasonable - although getting them all into one place might be harder.

Rather, I worry food riots and the associated issues such as blocked roads, torched buildings, looting, and so on could push a civilisation that is already severely damaged over the edge into total collapse.

[frank2]

Good point about the need to process the grains and beans. Here is the author of Nuclear War Survival Skills on the subject:

>Whole-kernel grains or soybeans cannot be eaten in sufficient quantities to maintain vigor and health if merely boiled or parched. A little boiled whole-kernel wheat is a pleasantly chewy breakfast cereal, but experimenters at Oak Ridge got sore tongues and very loose bowels when they tried to eat enough boiled whole-kernel wheat to supply even half of their daily energy needs. Even the most primitive peoples grind or pound grains into a meal or paste before cooking. (Rice is the only important exception.) Few Americans know how to process whole-kernel grains and soybeans (our largest food reserves) into meal. This ignorance could be fatal to survivors of a nuclear attack. Making an expedient metate, the hollowed-out grinding stone of Mexican Indians, proved impractical under simulated post-attack conditions. Pounding grain into meal with a rock or a capped, solid-ended piece of pipe is extremely slow work. The best expedient means developed and field-tested for pounding grain or beans into meal and flour is an improvised 3-pipe grain mill. Instructions for making and using this effective grain-pounding device follow. . . . As soon as fallout decay permits travel, the grain-grinding machines on tens of thousands of hog and cattle farms should be used for milling grain for survivors. It is vitally important to national recovery and individual survival to get back as soon as possible to labor-saving, mechanized ways of doing essential work. In an ORNL experiment, a farmer used a John Deere Grinder-Mixer powered by a 100-hp tractor to grind large samples of wheat and barley. When it is used to grind rather coarse meal for hogs, this machine is rated at 12 tons per hour. Set to grind a finer meal-flour mixture for human consumption, it ground both hard wheat and feed barley at a rate of about 9 tons per hour. This is 2400 times as fast as using muscle power to operate even the best expedient grain mill.

https://info.ornl.gov/sites/publications/Files/Pub57110.pdf

[lazyasciiart]

Food rotted in fields this year because the supply chain wasn't even agile enough to switch from supplying restaurants to supermarkets. Given actual disaster, distribution would be even harder because people would definitely attempt to hoard food.