In 2003 the General Assembly of the United Nations declared 2006 the International Year of Deserts and Desertification.
The objective is to help prevent the exacerbation of desertification worldwide by raising public awareness and supporting activities combating desertification and land degradation. Desertification is a major economic, social and environmental problem that affects one third of the world's land surface and about one billion people in more than one hundred countries. The article Assisting countries combat desertification - Australia's role in the International Relations chapter provides two examples of Australian Government assistance for research projects aimed at tackling land and water degradation, and efficient water allocation and management of the Yellow River Basin in China.
Apart from Antarctica, Australia is the driest continent in the world and has the largest desert region in the southern hemisphere. More than a third of the continent is effectively desert; over two thirds of the continent is classified as arid or semi-arid. Inclusion of semi-arid lands leads to a much wider conceptualisation of the Australian desert region, extending as far north as Wyndham in the Kimberley region of Western Australia and the Roper Valley in the Northern Territory, as far east as the slopes of the Great Dividing Range in Queensland and New South Wales, as far south as the Murray and Mallee in Victoria, and south west to the edge of the wheat belt in Western Australia.
Specialist authors from the Australian Bureau of Meteorology, the National Museum of Australia, and the Northern Territory Parks and Wildlife Service were invited by the Australian Bureau of Statistics to contribute to this feature article. Their responses address three related aspects of Australia's deserts - climatic aspects and characteristics; the archaeology and environmental history; and desert flora and fauna. The Geography and climate chapter which follows this article also contains some information relating to Australia's deserts and, more generally, the evolution of Australia's landforms.