Australia is the driest inhabited continent on Earth. Indeed, only Antarctica is drier (in terms of precipitation). A significant part of its landmass is desert and it contains the largest desert region in the southern hemisphere. Deserts form a large part of what is known as the “outback,” the sparsely populated interior of the country, most of which receives little rainfall, even if not classified as desert.
Deserts make up 18 percent of the land mass of mainland Australia. They are primarily found in central regions, in the interior lowlands and in western areas, known as the western plateau. This corresponds with the location of deserts around the world, with the vast majority occurring approximately 30 degrees north or south of the equator.
Largest and Smallest
The largest single desert area in Australia is the Great Victoria Desert. Located in the southern part of Western Australia, it covers an area of 163,900 square miles, equivalent to 4 percent of Australia's landmass. The smallest is the Pedirka Desert located in South Australia, which covers 480 square miles, 0.1 percent of the continent's landmass.
All of the deserts in Australia are classified as subtropical deserts. These are caused by atmospheric circulations in weather systems. Hot, moist air rises at the equator, moves over the tropics where the moisture falls as rain, and sinks at the subtropical regions (around the latitudes mentioned above). The air is now dry, and warms as it sinks closer to the ground, encouraging evaporation of any surface water.
The subtropical deserts of Australia are characterized not only by their low precipitation but also their extremely high temperatures. These can reach over 122 degrees F. Rainfall tends to be below 10 inches per year (compared to Brisbane, which sits on the same latitude but is on the coast, which has 46 inches), while humidity can be as much as 20 percent.
In order to survive in the deserts of Australia, the fauna has had to adapt its behavior. Many animals are nocturnal, moving around and searching for food at night when it is cooler. They will spend the day in burrows underground, away from the searing heat. Both the Perentie lizard and the bilby (a small vole-like mammal that the Perentie preys on) use this strategy. Many birds have adapted so that they can get all the water they need from the seeds they eat, while kangaroos hop because it is the most efficient way to travel and they need to cover great distances searching for sparse food.