Australia

Contents 1. Physical geography 2. Political geography 3. Climate 4. Natural hazards 5. Environment

Australia is a country, and a continent. It is located in Oceania between the Indian Ocean and the South Pacific Ocean. It is the sixth largest country in the world with a total area of 7,686,850 square kilometers (including Lord Howe Island and Macquarie Island), making it slightly smaller than the 48 states of the contiguous United States and 31.5 times larger than the United Kingdom.

The Australian mainland has a total coastline length of 35,876 km with an additional 23,859 km of island coastlines. There are 758 estuaries around the country with most located in the tropical and sub-tropical zones. Australia has the largest area of ocean jurisdiction of any country on earth. It has no land borders.

Australia is the lowest, flattest, and oldest continental landmass on Earth and it has had a relatively stable geological history. Geological forces such as tectonic uplift of mountain ranges or clashes between tectonic plates occurred mainly in Australia's early history, when it was still a part of Gondwana.

Its highest peak is Mount Kosciuszko at 2,228 metres, which is relatively low in comparison to the highest mountains on other continents. Erosion has heavily weathered Australia's surface.

Australia is situated in the middle of the tectonic plate, and therefore currently has no active volcanism. Minor earthquakes which produce no damage occur regularly, while major earthquakes measuring greater than magnitude 6 occur on average every five years. The terrain is mostly low plateau with deserts, rangelands and a fertile plain in the southeast. The Great Barrier Reef, by far the world's largest coral reef, lies a short distance off the north-east coast.

Continents of Australia

The Australian continental landmass consists of 6 distinct landform divisions. The Eastern Highlands—including the Great Dividing Range, the fertile Brigalow Belt strip of grassland behind the east coast, and the Eastern Uplands The Eastern alluvial Plains and Lowlands— Murray Darling basin covers southern part, also includes parts of the Lake Eyre Basin and extends to the Gulf of Carpentaria

The South Australian Highlands—including the Flinders Range, Eyre Peninsula and Yorke Peninsula The Western Plateau—including the Nullarbor Plain The Central Deserts Northern Plateau and Basins—including the Top End

The Hydrology of Australia Because much of Australia's interior is arid, the low average annual rainfall means interior rivers are often dry and lakes empty. The headwaters of some waterways are located in tropical regions where summer rains create a high rate of discharge. Flood events drastically alter the dry environment in which the ecology of central Australia has had to adapt to the boom and bust cycle.

The Great Artesian Basin is an important source of water, the world's largest and deepest fresh water basin. Access to water from the basin has led to the expansion of grazing into areas that were previously far too dry for livestock.

Towns and cities across the country sometimes face major water storage and usage crisis in which restrictions and other measures are implemented to reduce water consumption. Water restrictions are based on a gradient of activities that become progressively banned as the situation worsens.

Political geography Australia consists of six states, two major mainland territories, and other minor territories. The states are New South Wales, Queensland, South Australia, Tasmania, Victoria and Western Australia. The two major mainland territories are the Northern Territory and the Australian Capital Territory. Western Australia is the largest state covering just under one third of the Australian landmass, followed by Queensland and New South Wales.

Australia also has several minor territories; the federal government administers a separate area within New South Wales, the Jervis Bay Territory, as a naval base and sea port for the national capital. In addition Australia has the following, inhabited, external territories: Norfolk Island, Christmas Island, Cocos (Keeling) Islands, and several largely uninhabited external territories: Ashmore and Cartier Islands, Coral Sea Islands, Heard Island and McDonald Islands and the Australian Antarctic Territory.

Billabong is the Australian name given to the oxbow lakes that can form along a meandering river's course. In a world-wide comparison of height, Australia's waterfalls are relatively insignificant, with the longest drop ranked 135th according to the World Waterfall Database.

Climate By far the largest part of Australia is arid or semi- arid. A total of 18% of Australia's mainland consists of named deserts,[8] while additional areas are considered to have a desert climate based on low rainfall and high temperature. Only the south-east and south-west corners have a temperate climate and moderately fertile soil. The northern part of the country has a tropical climate: part is tropical rainforests, part grasslands, and part desert.

Rainfall is highly variable, with frequent droughts lasting several seasons thought to be caused in part by the El Niño-Southern Oscillation. Occasionally a dust storm will blanket a region or even several states and there are reports of the occasional large tornado. Rising levels of salinity and desertification in some areas is ravaging the landscape.

Australia's tropical/subtropical location and cold waters off the western coast make most of western Australia a hot desert with aridity, a marked feature of the greater part of the continent. These cold waters produce little moisture needed on the mainland.

A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia. The outback covers 70 percent of the continent.

Natural hazards Cyclones along the northern coasts, severe thunderstorms, droughts, occasional floods, heat waves, and frequent bushfires are natural hazards that are present in Australia.

Environment Current environmental issues include: soil erosion from overgrazing, industrial development, urbanization, and poor farming practices; soil salinity rising due to the use of poor quality water; desertification (partly as a result of the introduction by European settlers of Rabbits);

introduced pest species; clearing for agricultural purposes threatens the natural habitat of many unique animal and plant species; the Great Barrier Reef off the northeast coast, the largest coral reef in the world, is threatened by increased shipping and its popularity as a tourist site; limited natural fresh water resources; threats from invasive species.

International agreements: Antarctic-Environmental Protocol, Antarctic Treaty, Kyoto Protocol, Biodiversity, China– Australia Migratory Bird Agreement, Climate Change, Endangered Species, Environmental Modification, Hazardous Wastes, Japan–Australia Migratory Bird Agreement, Law of the Sea, Marine Dumping, Marine Life Conservation, Nuclear Test Ban 1963, Nuclear Non-Proliferation, Ozone Layer Protection, Ship Pollution, Tropical Timber 1994, Ramsar Convention, Whaling signed, but not ratified: Desertification

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