The High Carrying Capacity of the Pan-Tibetan Watershed
Asia has more than half of the world’s population. In particular, East Asia, South Asia and Southeast Asia has the highest population density, from ancient time to modern day. How can this area sustain such a high human population? I think this is because the high elevation gradient pan-Tibetan watershed is consistently nourished and renourished by the nutrient rich new deposits.
Plants extract nutrients from the soil. If the soil is not replenished by nutrient rich new deposits, soil will be deficient of some vital minerals (vitamins) for the growth of plants. The Tibetan Plateau is high and gigantic. It provides a reliable source of new minerals to supply the vast pan Tibetan watershed. This is probably the most important reason for the sustained high population density over a long period of time in this area.