Around 70% of the earth’s surface is covered in water, leaving only 30% as land; however within this portion exist many physical features that restrict human habitation. Only around 11% of the earth’s surface poses no serious threat to human settlement and 80% of the world’s 6.7 billion people live on 10% of the earth’s surface.
The majority of the world’s population reside in the Northern Hemisphere; the sole reason for this being that the majority (63-70%) of the world’s total land mass is situated there.
Of the 80% of the world’s population who live in the Northern Hemisphere, around two-thirds dwell in the mid-latitudes between 20? and 60? North.
There are four main clusters of population in the world. In terms of largest population, the first is East Asia, which includes China, Japan, Taiwan and North and South Korea. East Asia contains about 25% of the world’s population and has a climate and sufficient water sources essential for agriculture, allowing the sustenance of large populations.
The second largest cluster is South Asia, which contains about one-fifth of the world’s population. Next is Europe, which contains about 13% of the world’s population and supports high urban densities due to its strong manufacturing base. The final cluster is North-eastern USA/southern Canada, which has a rich agricultural base and natural resources of coal iron ore, natural gas and oil. Population densities within these regions are over 50 people/km2.
There are also fourteen smaller clusters of population with population densities of 10-50 people/km2. Included in this group are eastern Australia, the islands of the Caribbean, Mexico City, central Chile and east-central Africa.
The situation of large populations is customarily determined by the restraints and opportunities of the...