Australia is the driest inhabited continent on Earth, with a significant portion of its landmass classified as arid or semi-arid, often collectively referred to as the Outback. This vast interior is home to numerous massive deserts, which together cover approximately 18% of the country’s mainland. Although many Australians live on the temperate coastlines, these immense, dry regions play a fundamental role in the continent’s geography and ecology.
The Largest Desert Defined
The largest desert in Australia is the Great Victoria Desert (GVD), a colossal stretch of arid land that spans the states of Western Australia and South Australia. This desert is enormous, covering an area of approximately 348,750 square kilometers, which is larger than the entire landmass of the United Kingdom. The GVD extends for over 700 kilometers from the Eastern Goldfields region of Western Australia to the Gawler Ranges in South Australia, north of the Nullarbor Plain.
The landscape of the Great Victoria Desert is not uniform, consisting of small sandhills, plains with a closely packed surface of pebbles—known as gibber plains—and numerous salt lakes. Average annual rainfall is low and highly irregular, typically ranging between 200 and 250 millimeters per year. Summer daytime temperatures in the GVD are high, often reaching between 32 to 40 degrees Celsius.
Defining Australia’s Deserts
The classification of Australia’s deserts relies on more than just the presence of large sand dunes. The primary criteria used by bodies like the Bureau of Meteorology focus on ecological aridity, defined by low rainfall and high evaporation rates. While internationally a desert is often defined as receiving less than 250 millimeters of rain annually, Australian deserts can sometimes exceed this due to uneven rainfall distribution. Seventy percent of the Australian mainland receives less than 500 millimeters of rain per year, classifying it as arid or semi-arid, largely due to a belt of high-pressure systems around the 30-degree south latitude that suppresses rainfall. This dryness, combined with high temperatures and infertile soils, creates environments hostile to sustained plant life and agriculture.
Comparison with Other Major Australian Deserts
The Great Victoria Desert is the undisputed largest, but it is one of ten distinct deserts that collectively form the Great Australian Desert complex. The largest deserts by area are:
- The Great Sandy Desert, covering around 267,250 square kilometers, located primarily in Western Australia.
- The Tanami Desert at approximately 184,500 square kilometers.
- The Simpson Desert spans 176,500 square kilometers and is known for having the world’s longest parallel sand dunes.
- The Gibson Desert, the fifth largest, covers about 156,000 square kilometers.
Other major deserts include the Little Sandy Desert, the Strzelecki Desert, and the Sturt Stony Desert.