THE CONTINENT: AUSTRALIA

Australia's land mass

Australia comprises a land area of about 7.692 million square kilometres.

Although this is just five per cent of the world's land mass (149.45 million square kilometres), Australia is the planet's sixth largest country after Russia, Canada, China, the United States of America and Brazil. It is also the only one of the largest six nations that is completely surrounded by water.

Australia's land mass is:

• almost as great as that of the United States of America
• about 50 per cent greater than Europe, and 
• 32 times greater than the United Kingdom. 

Geographical and climatic features

Australia is the smallest of the world's continents. It is also the lowest, the flattest and (apart from Antarctica) the driest.

The highest point on the Australian mainland is Mount Kosciuszko, New South Wales, at 2228 metres above sea level. The lowest point is the dry bed of Lake Eyre, South Australia, which is 15 metres below sea level.

The mainland and Tasmania are surrounded by many thousands of small islands and numerous larger ones. Nearly 40 per cent of the total coastline length comprises island coastlines. As an island nation, coastlines play an important role in defining national, state and territory boundaries.

Nearly 20 per cent of Australia's land mass is classified as desert. As well as having a low average annual rainfall, rainfall across Australia is also variable. The rainfall pattern is concentric around the extensive arid core of the continent, with rainfall intensity high in the tropics and some coastal areas.

Climatic zones range from tropical rainforests, deserts and cool temperature forests to snow covered mountains.

Within this climate, our plants and animals have evolved on a geographically isolated continent, through a time of a slowly drying climate, combined with continuing high variability. The uniqueness of much of Australia's flora and fauna is thus at least partly due to these features of our climate.

Australian people

Australia is one of the most ethnically diverse societies in the world today.

Almost one in four Australian residents were born outside of Australia and many more are first or second generation Australians, the children and grandchildren of recently arrived migrants and refugees.

This wide variety of backgrounds, together with the culture of Indigenous Australians who have lived on the Australian continent for more than 50,000 years, have helped create a uniquely Australian identity and spirit.

Natural environment

Land

Australia has some of the oldest land surface on earth and while rich in biodiversity its soils and seas are among the most nutrient poor and unproductive in the world. This is due mainly to the country's geological stability, which is a major feature of the Australian land mass, and is characterised by, among other things, a lack of significant seismic activity.

Only six per cent of the Australian landmass is arable. Large volumes of water are required from both surface and groundwater supplies. Australian soils are highly dependent upon vegetation cover to generate nutrients and for stability. Land clearing, water extraction and poor soil conservation are all causes of a decline in the quality of Australia's soils.

Water

Australia is the driest inhabited continent on earth, with the least amount of water in rivers, the lowest run-off and the smallest area of permanent wetlands of all the continents.

One third of the continent produces almost no run-off at all and Australia's rainfall and stream-flow are the most variable in the world.

Human activity continues to exert pressure on marine environments. Pollution is the most serious problem and the vast majority of marine pollution is caused by land based activities — soil erosion, fertiliser use, intensive animal production, sewage and other urban industrial discharges.

Australia currently has 65 Ramsar (an international convention that provides the framework for conservation of wetlands) listed wetlands covering 7.5 million hectares and more than 850 of national importance. Australia's marine environment is home to 4000 fish species, 500 coral species in the northern reefs alone, 50 types of marine mammal and a wide range of seabirds. It is estimated that as many as 80 per cent of marine species found in southern Australian waters occur nowhere else.

Biodiversity

Australia is one of the most biologically diverse countries on the planet. It is home to more than one million species of plants and animals, many of which are found nowhere else in the world, and less than half have been described scientifically.

About 85 per cent of flowering plants, 84 per cent of mammals, more than 45 per cent of birds, and 89 per cent of inshore, freshwater fish are unique to Australia.

Australia is richly endowed with marsupials — there are more than 140 species.

At least 18 exotic mammals have established feral populations in Australia, with cats and foxes responsible for the decline and extinction of several native animals.

At least 2700 non-native (introduced) plants have established populations in Australia. Sixty-eight per cent of these introduced plants are considered a problem for natural ecosystems.