You can grow a lot of calories of potatoes in not much soil. There’s a reason the Irish diet was close to a monoculture.
I thought the English were shipping most agricultural products out of Ireland. Apparently no one in Europe wanted potatoes.
Nitpick: 1.2 billion pounds, not tons. (Unless you were talking about the Moon.)
Can you please stop making up things and promoting ignorance? You are constantly making incorrect and unfounded assertions.
The Grameen microcredit model is not “bypassing” any global banking, it is lending at high interest rate that is unsecured to either the solidarity group or the family for the short term funding.
There is no bypassing, it a customer segment that is not bankable in the classic bank structure of the deposit taking bank, for they are too risky and too expensive for such entities to reach.
If you think someone is factually incorrect, then feel free to point it out, civilly. But this type of accusation isn’t going to do anything to promote discussion. Please don’t do this.
Klebsiella planticola. Here’s a Cracked article about the experiment, which was the least woo-ish cite I could find. Take that for whatever its worth.
Agree with Ramira.
Grameen is also an effort that has since been largely discredited as not actually achieving most of the supposedly good outcomes it initially claimed for itself.
There was a SF disaster novel about a disease that wiped out all grass species: this would include wheat, rice, corn, oats, barley, sorghum, rye, millet, and other grains. This wouldn’t eliminate all food sources but it would eliminate a substantial portion.
English absentee landowners had bought up all the good cropland and used it to grow crops like wheat, which was exported out of Ireland. The Irish people ate potatoes which could be grown in the marginal cropland that was left over.
This was a major reason the famine had such political consequences. When the potatoes were killed by disease and Irish people were starving, they could see other crops being grown in nearby fields and watch as those crops were harvested and sent to England.
The Death of Grass, also filmed as No Blade of Grass.
They would after the famines hit. The first places to feel the crisis would be the cities. That would very quickly lead to food riots, just plain riots, looting and massive burnouts of city centers, with the accompanying population crash. The survivors would have plenty of now-available space on which to grow crops.
You’re assuming control would be lost and that governments have no stocks of food. While I’m sure you’re right about the developing world, are you sure about the developed world?
Well, that was part of the problem, but it’s all related to poverty.
The Irish were very poor, greatly as a result of an unequal power structure in which the English effectively owned large amounts of land and extracted painful rents.
So, any cash crop was primarily grown for export. And the crop the Irish grew for themselves to eat was the one that they could get the most calories out of the least land. Because they didn’t have much land, and any land that wasn’t used for their own consumption could be used to grow those cash crops that they needed in order to buy things that weren’t food.
Food and Agriculture Organization of the United Nations on staple food nutrition
Potatoes aren’t the most calorie-dense food you can grow, but they’re way up there among staples (Sweet potatoes are higher). And they have more protein than most as well, which is important because when you’re busy not starving, protein can be harder to come by. And tubers much easier to grow and harvest than grains. Potatoes can be fairly easily planted and harvested by hand, but good luck flooding your backyard for rice or harvesting and processing wheat by hand.
Yep. NYC is toast. Too many people in too small a space. It takes everything a fully-functioning, modern food distribution system can handle today. Throw a world-wide shortage of food into the mix and they die. The artificial construct collapses.
Of course, the rest of the planet will have it worse. Famine will mean that all the foodstuffs produced in the US and Canada will stay in the US and Canada. Although, as noted above, we will probably export quite a bit to Mexico in exchange for cheap labor (just like we do now!) 
As a side note, there are a couple of novels out there that deal with just this idea. Look up Harry Turtledove’s Supervolcano: Eruption and its sequels.