> It will be hard to convince Asians to eat much less rice though.

that's an odd thing to focus on. Moving people off meat & cheese would do a whole hell of a lot more than moving people off rice.

There's also some interesting work being done on growing rice in brackish water which could turn some unarable land to arable.

Farming is also mostly an energy problem. Assuming cheap energy, you can create hydroponics that scale vertically. Highrise farms, and they could consume electricity during off-peak times when it is extremely low cost.

Water is also not a problem, we are surprisingly good at treating water, can even turn saltwater into freshwater given sufficient energy.