with less people to grow food for the less food you need to grow. but even if china has a population of 100 million it would still remain food insecure with it's awful terrain, ruined ecosystem and inefficient production methods, in which case they'll still depend on western farmers to feed their over-leveraged mouths.  you don't seem to grasp the basic understanding that we exist in finite habitats on a finite planet. maybe go look around your immediate surroundings and ask yourself about the wider consumption footprint beyond your immediate vicinity instead of debating with innane points.
Australia