Except, as we see, that kind of thinking didn't end after the Second World War; it just went into remission.

Famine is never agricultural. It is always political.

Agriculture is unnatural (as are cities).

Farming is a response to over population.

The natural Earth is basically automated for humans.

We get some sticks and kill a buffalo or a cave lion and eat meat. It's pretty easy, and we end up with a net energy gain.

That's what this guy says, anyway:

http://www.themandus.org/

After calling for an Amazon boycott, there's this link to the Amazon page for Martin's book. So all of that "activism" was just sound and fury, signifying nothing, then?

The problem is the English lords imposed potato monocultures as compared to the varied diet before, exacerbated by punitive taxes and trade restrictions.

The English overlords were exporting wheat from Ireland during the famine years. Grain is for profit, not for feeding the neighbors. Maude Gonne sold her diamonds to buy grain to feed people; grain was available, at a price. (This is my old personal memory-retrieval system at work; Ireland scholars please correct & clarify.)

You never actually mention the reason the blight became a famine. It is because potatoes, like apples and tulips, do not breed true from seeds. That is, growing one from a seed will produce a plant whose tubers (or fruit, or flowers) are very different from its parent's. Therefore, these crops are propagated via cloning: potatoes by planting sections of tubers, apples by growing trees from cuttings, and tulips by planting bulblets.
However, these clones are (by definition) identical to each other. Without a varied initial selection to create diversity and recombination to maintain it, every single individual has the same strengths and weaknesses. So when a strain of fungus emerges that one plant has no resistances to...every other plant is helpless against it.
The Mayans didn't have potato blights. They grew potatoes from seed and from tubers, producing a wide array of spuds and avoiding any monoculture. If a fungus killed one variety, there were plenty more to fall back on.

@3: I'll one-up you: http://www.timecube.com

@7 - Exactly! Lack of biodiversity was the cause of the Irish potato famine. A great read on the subject of biodiversity is 'The Botany of Desire'. It talks about the McDonald-ization of many of our key crops, and the risky road we're traveling for the sake of the perfect looking french fry.