The term Northern Australia includes those parts of Queensland and Western Australia
north of latitude 26° and all of the Northern Territory.
Those local government areas of Western Australia and Queensland that lie partially in the north
are included.
Although it comprises about half of the total area of Australia, Northern Australia includes
only about one quarter of the Australian population.
However, it includes several sources of Australian exports, being coal from the Great Dividing
Range in Queensland/New South Wales and the natural gas and iron ore of the Pilbara region
in WA.
It also includes major natural tourist attractions, such as Uluru (Ayers Rock), the Great Barrier
Reef and the Kakadu National Park.
== Geography and climate == Almost all of Northern Australia is a huge
ancient craton that has not experienced geological upheaval since the end of the Precambrian.
The only exception to this generalisation is the Wet Tropics of northern Queensland,
where active volcanoes have been present as recently as the Pleistocene.
The vast craton in the north and west contains a number of quite rugged mountain ranges,
of which the highest are the MacDonnell and Musgrave Ranges on the southern border of
the Northern Territory.
These rise to over 1,500 metres (4,900 ft), but the most spectacular features are the
deep gorges of rivers such as the Finke.
Most of the craton, however, is distinctly flat and generally low-lying with an average
elevation of around 400 metres (1,300 ft), whilst in the Lake Eyre Basin most of the
land is not far above sea level.
The climate of the north of Australia ranges from arid (Köppen BWh) in the south to monsoonal
(Köppen Aw) in the Top End and Kimberley.
On the eastern coast, however, the climate is much more humid and ranges from humid sub-tropical
(Köppen Cfa around Brisbane and Cwa further north) to humid tropical (Köppen Am and Af)
in the Wet Tropics.
Except in the western part of the Pilbara and Gascoyne where the heaviest rain often
occurs from May to July under northwest cloudbands, rainfall is heavily concentrated in the "summer"
months from November to March.
For instance, in Burketown, the months May to September are rainless in over fifty percent
of years, with over eighty percent of Augusts having no rain.Temperatures in summer are
generally unpleasantly hot apart from the eastern coastal belt.
Maximum temperatures elsewhere between October and April range from 30 °C (86 °F) in the
south in April to around 40 °C (104 °F) in the inland Pilbara and Kimberley before
the wet season breaks.
Further north, maxima are consistently around 32 °C (90 °F) but extreme humidity makes
conditions very unpleasant.
On the coast, maxima in January range from 29 °C (84 °F) in the south to 32 °C (90
°F), with minima generally around 21 °C (70 °F).
In July, temperatures show a wider range, from 31 °C (88 °F) in the north to around
19 °C (66 °F) in the south, where minima can be as low as 5 °C (41 °F) in Alice Springs
in June and July.
=== Climate variability === The above generalisations, however, mask the
immense variability of the climate throughout the whole region.
With the exception of the extreme north of the Northern Territory, rainfall variability
throughout Northern Australia is quite markedly higher than most comparable climates in other
continents.
For example, at Charters Towers, the rainfall over the wet season can vary from less than
100 millimetres (3.9 in) in 1901/1902 to over 2,000 millimetres (79 in) in 1973/1974.
The chief cause of this very high variability is erratic tropical cyclones, which occur
from December to April and in many places can deliver as much as 350 millimetres (14
in) of rain over a day or two, causing extremely large floods in the region's rivers.
For example, in April 1898, a tropical cyclone gave 740 millimetres (29 in) in one day at
Whim Creek in the Pilbara, but for the whole of 1924 that same station recorded only 4
millimetres (0.16 in) for the whole year.
Tropical cyclones may cross the coast anywhere in Northern Australia but are most frequent
between Derby and Onslow on the west side and between Cooktown and Rockhampton on the
east.
Inland, variability of rainfall is related to the penetration of the summer monsoon,
with high rainfall in seasons like 1973/1974, 1975/1976 and from 1998 to 2001 when the monsoon
is most powerful.
Climate change has seen increases of up to fifty percent in annual rainfall since 1967
over the western half of Australia's tropics, but has not seen any increase over the east.
The increase over the west is sometimes attributed to aerosol pollution over industrialising
areas of China and India, but may be related to global warming.
Frosts are common in the southern inland during the winter, but in some years, such as 1998,
they are much less frequent due to the recent incidence of warm pools in the Indian Ocean.
== Soils == Except in the Lake Eyre Basin and adjacent
areas to the east, the soils of Northern Australia are quite remarkable in global terms for their
low fertility and difficulty of working.
Most of them consist chiefly of hard laterite developed during period of climate much more
humid than even that of Darwin today.
Since there has been no mountain building in the region since the Precambrian and no
glaciation since the Carboniferous, the region's soils have generally been under continuous
weathering without renewal for over 250 million years, as against less than ten thousand for
most soils in Europe, Asia, North America and New Zealand which have been formed from
recent mountain building or glacial scouring of the land.
This immensely long weathering time means that nutrient levels in Northern Australian
soils are exceptionally low because practically all soluble minerals have long been weathered
out.
The major constituents of most soils in Northern Australia are iron and aluminium oxides, both
of which are not only very insoluble but also serve to reduce the soil pH and remove phosphorus
from the soil as insoluble iron and aluminium phosphates.
The insolubility of these metal oxides also serves, under the extremely harsh conditions
during the dry season in the north and generally in the south, to create massive sheets which
are impossible to plough.In the Lake Eyre Basin, deposition from volcanic regions to
the east has produce cracking clay soils of quite high fertility which are still often
fairly low in phosphorus but have very good levels of potassium, calcium and sulfur.
These soils provide the best grassland for grazing in the region.
The youthful, volcanic Wet Tropics has a number of areas of fertile alluvial soils that support
intensive horticulture.
== Flora and fauna == The extreme soil poverty of most of Northern
Australia has the effect of confining large herbivores such as the kangaroo to the better
soil in the dry grasslands since they cannot digest the extreme poor fodder from the northern
monsoonal regions.
However, the frequency of fires during the desiccating dry season from May to September
means that forests cannot establish themselves except in sheltered places.
This has created a unique type of tropical savanna environment in which fires play a
crucial role in elevating the extremely low nutrient levels and aiding growth during the
wet season.
The many large rivers of the region such as the Mitchell, Gilbert-Einasleigh, South and
East Alligator, Daly, Ord and Fitzroy support populations of the saltwater and freshwater
crocodiles, which are by far the best-known animals of the region.
There are also a number of species of python.
Further south, where rivers are not adequate to support crocodiles, there exist a number
of quite unique lizard species.
The Wet Tropics, like all tropical rainforests, is very rich in unique species, and importantly
contains some of the most primitive flowering plants in the world.
== Economy == The erratic climate and extreme soil poverty
have defied all attempts to develop large-scale agriculture in any part of Northern Australia
apart from the Wet Tropics, where sugar cane and banana growing is a major industry, and
the Lake Eyre Basin and surrounding areas where the dominant activity is rearing of
sheep and beef cattle on extremely large properties.
Despite the relatively fertile soils, land values owing to the extremely variable climate
are very low.
Beef cattle are raised elsewhere in the Northern Territory and Kimberley, but the quality of
meat is very low because animals are slaughtered at quite an old age compared to cattle elsewhere
in the world.
The geological factors that make Northern Australia's soils so unsuited to traditional
agriculture, however, make it extremely rich in ores of abundant, insoluble lithophile
metals such as aluminium, iron and uranium.
It has the world's largest deposits of all these metals, and as less reactive chalcophile
metals have been depleted Northern Australia has become very important to the economies
of mineral-poor Asian nations.
It was Northern Australian iron ore that fed the Japanese post-war economic miracle and
the Four Tigers of South Korea, Taiwan, Hong Kong and Singapore.
During the 1950s and 1960s, the government of Robert Menzies attempted to develop farming
in Northern Australia, but pests made this impossible even when varieties of rice suited
to the soils were developed.
Today, however, sugar cane growing has expanded into the Ord River basin without surpassing
cattle and tourism as the main industries of the region.
=== Proposals for development of Northern Australia ===
'Grand northern Australian development dreams are nearly as old as the nation itself and
have repeatedly failed to materialise.'Proponents for the development of Northern Australia
have been found since before Federation and include:
Alfred Searcy George Pearce
Gina Rinehart in Northern Australia and then some: changes we need to make our country
rich (2013) and through Australians for Northern Development and Economic Vision (ANDEV).The
latest iteration of these proposals is found in the Our North Our Future: White Paper On
Developing Northern Australia published by the Abbott Government on 18 June 2015.
== See also == Eastern states of Australia
North West Australia Western Australia
Southern Australia
== References ==
== Further reading == Richards, Leslie P (2007), A guide to cruising
Northern Australia : anchorages Darwin to Carnarvon (4th ed.), Adventure Yarns, ISBN
978-0-9751857-4-2