| Summary: | The Southern Hemisphere island continent of Australia (7 million km2) is old, flat, stable, and dry, with a high proportion of endemic biota. The environment of Australia is fundamentally shaped by its age, its aridity and interannual climate variability, and the role of fire. These help to explain the continent’s characteristic ecology, animals, and evergreen vegetation. Fire has also been the main tool used by indigenous populations to substantially alter the landscape in their 50,000 years of occupation. In just 200 years, a relatively small population of European colonizers (by world standards) has even more effectively transformed the environment of Australia through mining, land use change, invasive plants and animals, exploitation of water resources, and water quality degradation. Very high endemism is matched by some of the world’s highest rates of extinctions of plants and animals. Although human populations are clustered in capital cities, and on the coast, particular pressure has come on three globally notable environments: the Great Barrier Reef, Northern Australia, and the Great Artesian Basin. Parallel with destruction has been preservation, and Australia has a long history of environmental protection. Nearly 12 percent of the continent is in protected areas, including Australia’s sixteen UNESCO World Heritage Areas. There are also some globally notable developments in environmental management, including the burgeoning role of indigenous groups in managing over 30 percent of the continent, and radical water management in response to overexploitation of water resources. In the early 21st century, climate change influences every aspect of Australia’s environment. Australia also has seven external territories (including 42 percent of Antarctica) that are also of great environmental importance but are not covered in this review.
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