From a biological point of view, the Potato Famine could have been largely avoided if the Blight damaged potatoes had been left in the ground. Potato Blight kills off the leaves. It damages the tubers slightly, but what caused the problems was the farmers (quite understandably) digging up the tubers and clamping them. They then rotted.
If they'd have been left, most would have survived, and although the yield would have been less, and there would have been problems, it wouldn't have been anywhere near as bad as it was.
Sorry to go off at a tangent.