I don't think it's likely to cause human extinction if the Rice Belt moves up into, say, Arkansas, and the Corn Belt moves up into, say, Saskatchewan.
Your chart has very little to do with external conditions being "just right" and much more to do with presence of a technological infrastructure.
Are you seriously arguing that the natural climatic conditions are responsible for there being a higher population density in southern Canada than, say, Argentina?
Your chart has very little to do with external conditions being "just right" and much more to do with presence of a technological infrastructure.
Are you seriously arguing that the natural climatic conditions are responsible for there being a higher population density in southern Canada than, say, Argentina?