Are there 7 billions of farmland in S. America? As opposed to acres of the Andes mountains or desert or Tierra del Fuego or flooded several months of the year Amazon river bottom?
Except for thick alkali flats and the like, there’s farmland everywhere. Not much of the earth has a climate more brutally cold, dry and windy than mine.
People with a will to do so can install various kinds of water systems for wells or even desalinization plants. Most stories of local water shortages are false and are driven by corrupt political business agendas.
That’s why we’re eventually headed for technocracy...or else. For now, though, lazy-minded morons are most supported in leadership, academia and other comfortable positions. That’s the greatest current threat to the human population—not overpopulation.
Those are nothing more than tech problems. Even the Sahara Desert could be recoverable if we were willing to take the time and money to do so.
If you add to that we could go vertical if we really needed to do so, we could conceivably grow fifty times the amount of food than we currently do now.
The idea of the example was to remove people from the rest of the continents to show there is nothing close to overpopulation. See the point made was to put all o the people in S America giving you the REST OF THE PLANET TO GROW FOOD ON. So I am not sure what point you are trying to by asking how much farmland in South America there is. But understand you don't need much land to feed a human. It takes less than an acre per person way less if you are efficient with its use.
The USA could easily feed the world with the available farmland and pastureland we have. But even in the area I live in much of the available land is not utilized. When I was a kid everyone in town had a garden of some sort. Now hardly any house in town does.