https://en.wikipedia.org/wiki/Great_Leap_Forward#Consequence...
Compared to modern mass-scale industrial stock-farming killing the planet? Nothing really...
Depends on where you live (and most of current living where one can't make food and wouldn't survive a shortage has been enabled by "industrial farming" and other developments - e.g. enabling deserts cities in Nevada).
In my case, we have had hens, pigs, turkeys, olives, grapes, tomatoes, cucumbers, watermelons, oranges, figs, corn, berries, potatoes, and several other fruits and vegetables besides at the house at home. And this wasn't uncommon in my between ~150K strong place of birth (now I live in a much larger city), almost every family had such.
>In the good old days there would be a bad harvest every so many years and a substantial fraction of the population would starve to death in the ensuing famine.
We've had techniques to survive bad harvests, including long term storage, canned goods, saline storage, dried goods (from nuts to figs and salami), and so on, for millennia, and I don't remember any famines in my here parts (much less a "substantial fraction of the population starving to death"). Then there's always trade, which we also have had for quite a while.
The worst famines are not caused by bad harvests, they are either due to political reasons (from the Irish potato famine, to the 80s Ethiopian one, both caused by bad policies) or poor distribution/inequality (while food exists).
That's more about water than food per se, though they go hand in hand.
It indeed does help that nearly all major Nevadan cities (and the vast majority of Nevadans, in turn) happen to be near the border between Nevada and one of the world's primary agricultural powerhouses, though.
That is a spectacularly impractical idea.