Why is much of Australia dry and sparsely populated?

Australia is characterized by its aridity and sparse population primarily due to its climate and geography.

Climate and Aridity

Australia is the driest inhabited continent. Over two-thirds of its landmass receives less than 20 inches (500 mm) of annual rainfall, and one-third receives less than 10 inches (250 mm). This aridity is driven by several factors:1
* Atmospheric Pressure: Much of the continent is influenced by subtropical high pressure systems, which cause air subsidence that inhibits cloud formation and rainfall.2
* Topography: The Great Dividing Range acts as a barrier to moisture-bearing winds, creating rain shadows that leave the interior dry.13
* Variability: Rainfall is highly unpredictable, often influenced by the Southern Oscillation and the Indian Ocean Dipole, leading to frequent, prolonged droughts.1

Population Distribution

Because of these environmental constraints, the interior—often called the Outback—is sparsely populated. Most Australians reside in the more temperate coastal fringes where precipitation is adequate to support urban centers and intensive agriculture. While the interior supports large-scale pastoral stations and mining, it lacks the water resources necessary to sustain large towns or dense human settlement.4567