The first reason for the sparse population in South America is that the economy in South America is underdeveloped and cannot create a large number of employment opportunities.

Second, the terrain in South America is complex and there are not many places suitable for human habitation.

Third, the climate in South America is relatively humid and hot, which is not suitable for human habitation. The Amazon Yulin and plateau in South America occupy a large area. The climate in Yulin is humid and hot, and mosquito disasters are common, making it unsuitable for living; the plateau mountains are steep and the transportation conditions are poor. The plateau itself has scarce oxygen. The tall mountains in central South America block the atmospheric circulation of the ocean, and precipitation is scarce in many places.

The southernmost tip of South America has a high latitude, low temperature, and is cold all year round, which is not conducive to human habitation.

The southernmost tip of South America is close to the southern hemisphere, and the westerly belt has a harsh climate all year round, so it is difficult for humans to survive here