[usrusr]

> but also dramatic improvements in our ability to grow cheap food at a scale

Are those improvements sustainable? Agriculture that is generating high yields from converting very fertile natural ecosystems into deserts and then moving on is almost like eating through fossil resources, only that the timescale for replenishment is a few orders of magnitude closer to being relevant for humanity (but still far or of reach). Failure ecosystems that have been farmed out of existence in antiquity are still as barren as thousand years ago. If you ignore the yields of unsustainable farming, our ability to feed billions looks a lot less rosy.

[Turing_Machine]

"Are those improvements sustainable?"

Available evidence suggests yes.

http://plantsci.missouri.edu/grains/corn/graphs/USA-corn-yie...

"Agriculture that is generating high yields from converting very fertile natural ecosystems into deserts"

Iowa didn't look much like a desert the last time I was there.

"Failure ecosystems that have been farmed out of existence in antiquity are still as barren as thousand years ago"

Yeah, that's why you don't want to rely on "organic" farming. Good thing we don't do that any more.

[usrusr]

> Iowa didn't look much like a desert the last time I was there.

I don't know the specifics of Iowa, but European soil can only keep up with the rising yields thanks to the dung of a rising headcount of livestock that is fed with imported feed that is at least in part from slash-and-burn farming or from depopulating the oceans. If those animals consume more than the local yields could supply, the farming is still unsustainable despite local soils not depleting.

I'm not saying that there are no improvements (three certainly are), but that they might be much smaller than we think.

[Turing_Machine]

> slash-and-burn farming

Slash-and-burn farming is a "traditional", "organic" method.

They don't do slash-and-burn in Iowa.