Overblog Suivre ce blog
Editer l'article Administration Créer mon blog
10 novembre 2013 7 10 /11 /novembre /2013 06:05

The climate of Australia varies widely due to its large geographical size, but by far the largest part of Australia is desert or semi-arid. Only the south-east and south-west corners have atemperate climate and moderately fertile soil. SONY Vaio VGN-FS660/W CPU Fan

The northern part of the country has a tropical climate, varied between tropical rainforests, grasslands, part desert.

Australia's climate is ruled by the hot, sinking air of the subtropical high pressure belt which moves north and south with the seasons. This causes the rainfall pattern over Australia to be highly seasonal. HP Pavilion G61-631NR CPU Fan

Australia's rainfall is the lowest of the seven continents (besides Antarctica). Rainfall is variable, with frequent droughts lasting several seasons and is thought to be caused in part by the El Niño-Southern Oscillation.

Since it is a small continent separated from polar regions by the Southern Ocean, Australia does not get the harsh snaps of polar air that swarm over Northern Hemisphere continents during winter. HP Pavilion dv6560el CPU Fan

The continents in the Northern Hemisphere have a considerable temperature contrast between summer and winter, whereas in Australia the temperature contrast is small. In many parts of the country, seasonal high and lows can be great with temperatures ranging from above 50 °C (122 °F) to well below zero. Minimum temperatures are moderated by the lack of mountains and the influence of surrounding oceans. HP Pavilion dv6-2128ca CPU Fan

The El Niño-Southern Oscillation is associated to seasonal abnormality in many areas in the world, though Australia is one of the most affected continents, which experiences extensive droughtsalongside with considerable wet periods. Occasionally a dust storm will blanket a region and there are reports of the occasional tornado. Tropical cyclones, heat waves, bushfires and frosts in the country are also associated to the Southern Oscillation. HP Pavilion dv7-3004el CPU Fan

Rising levels of salinity anddesertification in some areas is ravaging the landscape.

Temperatures in Australia have followed an increasing trend between the years of 1910 to 2004 by approximately 0.7°C. Overnight minimum temperatures have warmed more rapidly than daytime maximum temperatures in recent years. The late-20th century warming has been largely attributed to the increased greenhouse effect. HP Pavilion dv7-4050ev CPU Fan

 [1] According to the Bureau of Meteorology, 80% of the land have a rainfall less than 600 mm (24 in) per year and 50% having even less than 300 mm (12 in).[2] As a whole, Australia has an annual average rainfall of 419 mm (16 in).

The rainfall patterns across Australia are highly seasonal. It however rains more in winter than in summer by approximately 11%, and compared to the Earth's other continental landmasses Australia is very dry. HP G42-367TU CPU Fan

More than 80% of the continent has an annual rainfall of less than 600 mm (24 in); only Antarctica receives less rainfall than Australia.[4] A place inland near Lake Eyre (in South Australia) would only receive 81 mm (3 in) of rain annually.[5] Another place,Troudaninna Bore (coordinates : 29° 11' 44" S, 138° 59' 28" E, altitude : 46 m) in South Australia, from 1893 to 1936, received, in average, 104.9 mm (4.13 inches) of precipitation.[6] HP Pavilion dv5-1172el CPU Fan

From one extreme to another, parts of the far North Queensland coast annually average over 4,000 mm (157 in), with the Australian annual record being 12,461 mm (491 in), set at the summit of Mount Bellenden Ker in 2000.

The average annual rainfall in the Australian desert is low, ranging from 81 to 250 mm (3 to 10 in) per year. Toshiba Satellite A105-S4084 CPU Fan

Thunderstorms are relatively common in the region, with an average of 15 - 20 thunderstorms per annum.[7] Summer daytime temperatures range from 32 to 40 °C (90 to 104 °F). In winter, this falls to 18 to 23 °C (64 to 73 °F).

The southern parts of Australia get the usual westerly winds and cold fronts that come with rain when the high pressure systems move towards northern Australian during winter. HP Pavilion dv4-1038tx CPU Fan

Cold snaps may bring frosts inland, though temperatures near the coast are almost mild all year round. Summers in southern Australia are generally dry and hot with coastal sea breezes. During a lengthy dry spell, hot and dry winds from the interior can cause bushfires in some of southern and eastern states, though most commonly Victoria and New South Wales. HP Pavilion dv7-3060sb CPU Fan

The tropical areas of northern Australia have a wet summer because of monsoon presence. During "the wet", typically October to April, humid north-westerly winds bring showers and thunderstorms. In occasional cases, tropical cyclones can bring heavy rainfall to tropical coastal regions, which are also likely to reach further inland. After the monsoonal season, the dry season comes ("winter"), which mostly brings clear skies and mild conditions. HP Pavilion dv7-6055sf CPU Fan

Low rate of evaporation from this very cool body of water result in little evaporation occurring. As a result, rain clouds are sparsely formed and very rarely do they form long enough for a continuous period of rain to be recorded. Australia's arid/semi-arid zone extends to this region. The absence of any significant mountain range or area of substantial height above sea level, results in very little rainfall caused by orographic uplift. SONY VGN-CS108D  CPU Fan

In the east the Great Dividing Rangelimits rain moving into inland Australia.

Australia has a compact shape and no significant bodies of water penetrate very far inland. This is important because it means that moist winds are prevented from penetrating to inland Australia, keeping rainfall low.

In Australia, snow falls on the highlands near the east coast, in the states of Victoria, New South Wales and Tasmania and the Australian Capital Territory. DELL XPS M170 CPU Fan

There is a regular snow season in several areas which have seasonal ski tourism industries. Sometimes snow has even been reported in the mountains of South Australia, Western Australia and Queensland, though this is rare.

Snow at sea level is occasionally recorded on mainland Australia, but is more frequent in Tasmania where snowfalls at sea level can occur during the winter months. Snow has been recorded across most of Tasmania, HP Pavilion G72-b15SV CPU Fan

though it is rare on the northern coast at sea level. Snow is rare in the southernmost capitals like Melbourne and Hobart, falling less than once every ten years, and in the other capitals it is unknown (however snow has fallen in the hill suburbs of Perth and Adelaide). However, there are extensive, well-developed ski fields in the Great Dividing Range, a few hours' drive from Melbourne and Sydney.[9] HP G62-120ES CPU Fan

The occasional cold snap, caused by cold air drifting north from Antarctica, can cause significant snowfall in rural areas, as well as major cities such as Hobart, Melbourne's outer mountain suburbs and Canberra. Such occasions are rare, but have occurred in 1951, 1986 and 2005.

Because of its elevation (650 m (2,130 ft)) and distance from the coast, HP Pavilion dv6-3034ss   CPU   Fan

the Australian Capital Territory experiences a continental climate, unlike many other Australian cities whose climates are moderated by the sea.[11] Canberra is notorious for hot, dry summers, and cold winters with occasional fog and frequent frosts. Many of the higher mountains in the territory’s south-west are snow-covered for at least part of the winter. HP Pavilion dv7-3165ef  CPU Fan

Thunderstorms can occur between October and March, and annual rainfall is 623 mm (25 in), with rainfall highest in spring and summer and lowest in winter

The highest maximum temperature recorded in the ACT was 42.8 °C (109.0 °F) at Acton on 11 January 1939. The lowest minimum temperature was −14.6 °C (5.7 °F)at Gudgenby on 11 July 1971. HP X16-1000 Series CPU Fan

Over half of New South Wales has an arid or semi-arid climate. However, the eastern portion has a temperate climate, ranging from humid subtropical to theCentral Coast and most of Sydney, and oceanic to the south coast. The Snowy Mountains region in the south-east falls in the alpine climate/highland climate zone, with cool to cold weather all year around and snowfalls in the winter. IBM ThinkPad Z61m  CPU Fan

Further inland, the climate gets semi-arid and a desert climate towards the western part of the state.

The weather in the south of the state is generally hot in summer and cool in the winter as the seasons are well-defined in the south. The hottest New South Wales Climate region is the north-west part of the state, seasons are not well-defined in the north, where summers are hot and can be wet and winters are cooler and drier. ACER Aspire One D250 CPU Fan

The coldest region is the Snowy Mountains where the snow and frost continues for quite long durations during the winter months.The highest maximum temperature recorded was 49.8 °C (121.6 °F) at Menindee in the state's west on 10 January 1939. The lowest minimum temperature was −23 °C(−9.4 °F) at Charlotte Pass on 29 June 1994 in the Snowy Mountains. ACER Ferrari 4000 CPU Fan

This is also the lowest temperature recorded in the whole of Australia excluding Australian Antarctic Territory.[13]

Rainfall varies throughout the state. The far north-west receives the least, less than 180 mm (7 in) annually, while the east receives between 600 to 1,200 mm (24 to 47 in) of rain.

The Northern Territory has two distinctive climate zones. HP G42-367TU CPU Fan

The northern end, including Darwin, has a tropical savanna climate (Köppen Aw)[22] with high humidity and two seasons, the wet (November to April) and dry season (May to October). During the dry season nearly every day is warm and sunny, and afternoon humidity averages around 30%. There is very little rainfall between May and September. Toshiba Satellite L350-146 CPU Fan

In the coolest months of June and July, the daily minimum temperature may dip as low as 14 °C (57 °F), but very rarely lower, and frost has never been recorded.The wet season is associated with tropical cyclones and monsoon rains. The majority of rainfall occurs between December and March (the Southern Hemisphere summer), when thunderstorms are common and afternoon relative humidity averages over 70% during the wettest months. HP Pavilion dv7-3131ez CPU Fan

On average more than 1,570 mm (62 in) of rain falls in the north. Thunderstorms can produce spectacular lightning displaysThe central region is the desert centre of the country, which includes Alice Springs and Uluru, and is semi-arid with little rain usually falling during the hottest months from October to March. Central Australia receives less than 250 mm (10 in) of rain per year. Dell Vostro 3450 CPU Fan

The highest maximum temperature recorded in the territory was 48.3 °C (118.9 °F) at Finke on 1 and 2 January 1960. The lowest minimum temperature was −7.5 °C(18.5 °F) at Alice Springs on 12 July 1976.

Because of its size, there is significant variation in climate across the state. Low rainfall and hot summers are typical for the inland west, a monsoonal 'wet' season in the far north, and warm temperate conditions along the coastal strip. SONY Vaio VGN-CR23/N CPU Fan

Inland and in southern ranges low minimum temperatures are experienced. The climate of the coastal strip is influenced by warm ocean waters, keeping the region free from extremes of temperature and providing moisture for rainfall.However, most of the Queensland populace experience two weather seasons: a "winter" period of rather warm temperatures and minimal rainfall and a sultry summer period of hot, sticky temperatures and higher levels of rainfall. HP Pavilion dv6-3043tx CPU Fan

The highest maximum temperature observed in the state is 49.5 °C (121.1 °F) at Birdsville on 24 December 1972. The temperature of 53.1 °C (127.6 °F) atCloncurry on 16 January 1889 is not considered official; the figure quoted from Birdsville is the next highest, so that record is considered as being official.

The lowest minimum temperature is −10.6 °C (12.9 °F) at Stanthorpe on 23 June 1961 and at The Hermitage on 12 July 1965. HP Pavilion dv6-3163eo CPU Fan

The majority of the state has the arid and semi-arid climates. The southern coastal parts of the state have a Mediterranean climate with mild wet winters and hot dry summers. The highest rainfall occurs along the southern coasts and the Mount Lofty Ranges (with an average annual rainfall of 1,200 millimetres (47 in) in the vicinity of Mount Lofty); HP Pavilion dv7-1003eo CPU Fan

the lowest rainfall occurs in the Lake Eyre basin where the average annual totals are less than 150 millimetres (6 in) and possibly even 100 millimetres (4 in). Most of the rain in the southern districts of the State fall during the winter months when the sub-tropical high-pressure belt is displaced to the north over the Australian continent.[25]

South Australia's mean temperature range is 29 °C (84 °F) in January and 15 °C (59 °F) in July. Dell Vostro 3450 CPU Fan

Daily temperatures in parts of the state in January and February can be up to 48 °C (118 °F). The highest maximum temperature was recorded as 50.7 °C (123.3 °F) at Oodnadatta on 2 January 1960, which is the highest official temperature recorded in Australia. The lowest minimum temperature was −8 °C (17.6 °F) at Yongala on 20 July 1976.

Tasmania has a cool temperate climate with four distinct seasons.  HP Pavilion dv7-3067nr CPU Fan

Summer lasts from December to February when the average maximum sea temperature is 21 °C(70 °F) and inland areas around Launceston reach 24 °C (75 °F). Other inland areas are much cooler with Liawenee, located on the Central Plateau, one of the coldest places in Australia with temperatures in February ranging between 4 to 17 °C (39 to 63 °F). SONY Vaio VGN-CR23/N CPU Fan

Autumn lasts between March and May and experiences changeable weather, where summer weather patterns gradually take on the shape of winter patterns.

The winter months are between June and July and are generally the wettest and coolest months in the state, with most high lying areas receiving considerable snowfall. HP Pavilion dv7-1129wm CPU Fan

Winter maximums are 12 °C (54 °F) on average along coastal areas and 3 °C(37 °F) on the Central Plateau, thanks to a series of cold fronts from the Southern Ocean.[27] Spring is a season of transition, where winter weather patterns begin to take the shape of summer patterns, with snowfall still common up until October. Spring is generally the windiest time of the year with afternoon sea breezes starting to take effect on the coast. HP Pavilion G72-b15EV CPU Fan

Rainfall in Tasmania follows a complicated pattern rather analogous to that found on large continents at the same latitude in the Northern Hemisphere. On the western side rainfall increases from around 1,458 mm (57 in) at Strahan on the coast up to 2,690 mm (106 in) at Cradle Valley in the highlands.[28]

There is a strong winter maximum in rainfall: January and February typically averages between 30-40% the rainfall of July and August, Compaq Presario CQ60-417DX CPU Fan

though even in the driest months rain usually falls on every second day and the number of rainy days per year is much greater than on any part of the Australian mainland. Further east in the Lake Country, annual rainfall declines to around 900 mm (35 in), whilst in the Midlands, annual rainfall is as low as 450 mm (18 in) at Ross and generally below 600 mm (24 in). HP Pavilion dv7-3080eg CPU Fan

The eastern part of Tasmania has more evenly distributed rainfall than in the west, and most months receive very similar averages.The densely populated northern coast is much drier than the western side, with annual rainfall ranging from 666 mm (26 in) in Launceston to 955 mm (38 in) in Burnie in the north west and 993 mm (39 in) in Scottsdale located further to the east.[29][3HP Pavilion dv9233ca CPU Fan

0]Most rain falls in winter, and in summer the average can be as low as 31 mm (1 in) per month in Launceston. The east coast is wetter than the Midlands, with an average annual rainfall ranging from 775 mm (31 in) in St. Helens to around 640 mm (25 in) in Swansea.[31][32] Here the rainfall is evenly distributed over the year but can be very erratic as heavy rainfalls from the warm Tasman Sea are quite frequent. HP Envy 14-1195la CPU Fan

Whereas a three-day fall of 125 mm (5 in) occurs only once every fifty years on the north coast, it occurs on average once every four or five years around Swansea and Bicheno, and on 7–8 June 1954, there were many falls as large as 230 mm (9 in) in two days in that area. The east coast is sometimes called the "sun coast" because of its sunny climate.[33] HP Pavilion dv6-2115sf CPU Fan

Several sections of inland Tasmania, together with Flinders Island, were declared drought-affected areas by the state government in 2007.[34]

The highest recorded maximum temperature in Tasmania was 42.2 °C (108.0 °F) at Scamander on 30 January 2009, during the 2009 south-eastern Australia heat wave. Tasmania's lowest recorded minimum temperature was −13 °C (8.6 °F) on 30 June 1983, at Butlers Gorge, Shannon, and Tarraleah. HP Pavilion dv7-3067nr CPU Fan

Victoria has a varied climate despite its small size. It ranges from semi-arid and hot in the north-west, to temperate and cool along the coast. Victoria's main land feature, the Great Dividing Range, produces a cooler, mountain climate in the centre of the state.

Victoria's southernmost position on the Australian mainland means it is cooler and wetter than other mainland states and territories. HP Pavilion dv7-1129wm CPU FanThe coastal plain south of the Great Dividing Range has Victoria's mildest climate. Air from the Southern Ocean helps reduce the heat of summer and the cold of winter. Melbourne and other large cities are located in this temperate region.

The Mallee and upper Wimmera are Victoria's warmest regions with hot winds blowing from nearby deserts. Average temperatures top 30 °C (86 °F) during summer and 15 °C (59 °F) in winter. Victoria's highest maximum temperature of 48.8 °C (119.8 °F) was recorded in Hopetoun on 7 February 2009, during the 2009 south-eastern Australia heat wave.[13] A screen temperature of 50.7 °C (123.3 °F) was recorded on 7 January 1906 inMildura.[39][40] HP Pavilion G72-b15EV CPU Fan

The Victorian Alps in the north-east are the coldest part of Victoria. The Alps are part of the Great Dividing Range mountain system extending east-west through the centre of Victoria. Average temperatures are less than 9 °C(48 °F) in winter and below 0 °C (32 °F) in the highest parts of the ranges. The state's lowest minimum temperature of −11.7 °C (10.9 °F) was recorded at Omeo on 13 June 1965, and again at Falls Creek on 3 July 1970. HP Pavilion dv6-2140se CPU Fan

Victoria is the wettest Australian state after Tasmania. Rainfall in Victoria increases from north to south, with higher averages in areas of high altitude. Median annual rainfall exceeds 1,800 mm (71 in) in some parts of the north-east but is less than 250 millimetres (10 in) in the Mallee.

Rain is heaviest in the Otway Ranges and Gippsland in southern Victoria and in the mountainous north-east. SONY Vaio VGN-SZ6RXN/C CPU Fan

Snow generally falls only in the mountains and hills in the centre of the state. Rain falls most frequently in winter, but summer precipitation is heavier. Rainfall is most reliable in Gippsland and the Western District, making them both leading farming areas. Victoria's highest recorded daily rainfall was 375 millimetres (14.8 in) at Tanybryn in the Otway Ranges on 22 March 1983. HP Pavilion dv7-2130ev CPU Fan

The south-west corner of the state has a Mediterranean climate.[41] The area was originally heavily forested, including large stands of the karri, one of the tallest trees in the world. This agricultural region of Western Australia is in the top nine terrestrial habitats for terrestrial biodiversity, with a higher proportion ofendemic species than most other equivalent regions. ACER eMachines G520 CPU Fan

Thanks to the offshore Leeuwin Current the area numbers in the top six regions for marine biodiversity, containing the most southerly coral reefs in the world.

Average annual rainfall varies from 300 mm (12 in) at the edge of the Wheatbelt region to 1,400 mm (55 in) in the wettest areas near Northcliffe, but in the months of November to March evaporation exceeds rainfall, and it is generally very dry. HP Pavilion dv5-2132dx CPU Fan

Plants must be adapted to this as well as the extreme poverty of all soils. A major reduction in rainfall has been observed, with a greater number of rainfall events in the summer months.

The central four-fifths of the state is semi-arid or desert and is lightly inhabited with the only significant activity being mining. Annual rainfall averages about 200 to 250 mm (8 to 10 in), most of which occurs in sporadic torrential falls related to cyclone events in summer months. Compaq Presario CQ60-307ea CPU Fan

An exception to this is the northern tropical regions. The Kimberley has an extremely hot monsoonal climate with average annual rainfall ranging from 500 to 1,500 mm (20 to 59 in), but there is a very long almost rainless season from April to November. Eighty-five percent of the state's runoff occurs in the Kimberley, but because it occurs in violent floods and because of the insurmountable poverty of the generally shallow soils, the only development has taken place along the Ord River. HP Pavilion dv6-2010sa CPU Fan

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 a greater part of the continent. These cold waters produce precious little moisture needed on the mainland. A 2005 study by Australian and American researchers[42]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. Toshiba Satellite A40-702 CPU Fan

Occurrence of snow in the state is rare, and typically only in the Stirling Range near Albany, as it is the only mountain range far enough south and with sufficient elevation. More rarely, snow can fall on the nearby Porongurup Range. Snow outside these areas is a major event; it usually occurs in hilly areas of south-western Australia. The most widespread low-level snow occurred on 26 June 1956 when snow was reported in the Perth Hills, HP 535442-001 CPU Fan

as far north as Wongan Hills and as far east as Salmon Gums. However, even in the Stirling Range, snowfalls rarely exceed 5 cm (2 in) and rarely settle for more than one day.[43]

The highest observed maximum temperature of 50.5 °C (122.9 °F) was recorded at Mardie Station on 19 February 1998. The lowest minimum temperature recorded was−7.2 °C (19.0 °F) at Eyre Bird Observatory on 17 August 2008. HP 535441-001 CPU Fan

Climatic factors contribute to Australia's high incidence of bushfires, particularly during the summer months. Low relative humidity, wind and lack of rain can cause a small fire, either man-made or caused naturally by lightning strikes, to spread rapidly over large distances. Low humidity, the heat of the sun and lack of water cause vegetation to dry out becoming a perfect fuel for the fire. HP 535439-001 CPU Fan

High winds fan the flames, increasing their intensity and the speed and distance at which they can travel.[44]

Many of the worst bushfires in eastern Australia, such as the 1983 Ash Wednesday fires, accompany El Niño-Southern Oscillation events which tend to cause a warm, dry and windy climate.[45] The worst bushfires in Australian history occurred on Black Saturday in February 2009. HP 535438-001 CPU Fan

The human death toll of the disaster was 173, and over 2000 homes were lost.

Though Australia is generally dry and arid, a large portion of the country lives in the tropics. Rainfall in these areas is extremely heavy. With some are areas recording world record breaking rain, such as the mountains which lie to the south west of Cairns. HP 533736-001 CPU Fan

Through La Niña years the eastern seaboard of Australia records above average rainfall usually creating damaging floods.The 2010–2011 La Nina system has broken many rainfall records in Australia, particularly in the states of Queensland and New South Wales, which have seen extensive flooding which has caused major damage to infrastructure and crops. IBM 13R2760 CPU Fan

The central east area of Queensland, an area the size of Germany and France combined, was under water in 2010–2011. The estimated damage bill could reach into the billions.

According to the majority of scientists, climate change is predicted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO)[47] to have significant effects on the climate of and extreme weather events in Australia. ACER LU.S040A.067 CPU Fan

According to the Bureau of Meteorology, Australia’s annual mean temperature for 2009 was 0.90 °C (1.62 °F) above the 1961-90 average, making it the nation’s second warmest year since high-quality records began in 1910.[48]

It is predicted that the Great Barrier Reef and reefs surrounding Lord Howe Island could be killed as a result of the rise in water temperature forecast by the Intergovernmental Panel on Climate Change Fourth Assessment Report. ACER LU.S050B.078 CPU Fan

The Murray River, Darling River Coorong andMacquarie Marshes are all at risk from decreased rainfall from climate change.Coastal communities face risks from sea level rise, albeit over a long period of time based on current estimates of the IPCC Fourth Assessment Report. The Gold Coast, being built on sand and with many canal developments, could be considered particularly at risk. DELL Studio 1535 CPU Fan

Suburbs of Sydney like Drummoyne and Concord on rivers like the Parramatta River face risks of inundation of low lying areas such as parks (such as Timbrell Park and Majors Bay Reserve) reclaimed from mudflats at the heads of bays, or massive expenses in rebuilding seawalls to higher levels.

Currently, there are several environmental movements and campaigners advocating for action on climate change. HP Pavilion dv6736nr CPU Fan

One such campaign is "The Big Switch", Australia's largest community climate change campaign.

Drought in Australia is defined by rainfall over a three-month period being in the lowest ten percent of amounts having been recorded for that region in the past.[51] This definition takes into account that low rainfall is a relative term and rainfall deficiencies need to be compared to typical rainfall patterns including seasonal variations. HP Envy 15-1050ca CPU Fan

Specifically drought in Australia is defined in relation to a rainfall deficiency of pastoral leases and is determined by decile analysis applied to a certain area.[52]

Historical climatic records are now sufficiently reliable to profile climate variability taking into account expectations for regions.[53] State Governments are responsible for declaring a region drought affected and the declaration will take into account factors other than rainfall. HP Pavilion dv7-6100et CPU Fan

Australia is affected by tropical cyclones which primarily occur between December and April but have developed in November and May, as well.[54] Cyclones over mainland Australia occur on average five to six times each year.[4] The region between Broome andExmouth are most prone to cyclones.[55] Tropical cyclones are known to bring destructive winds, heavy rain with flooding creating storm surges along the coast, causing inundation in low lying areas. APPLE 661-4951 CPU Fan

The strongest Australian region cyclone was Cyclone Monica in 2006 which had wind gusts in excess of 350 km/h (220 mph). Cyclones can also move inland, decaying to a rain depression, which dump heavy rain in these areas and causing flooding.[56]

The worst cyclones of Australia have caused billions of dollars of damage and many deaths. IBM 42W2403 CPU Fan

Cyclone Tracy crossed directly over Darwin in 1974, 71 people were killed. Adjusted for inflation it was Australia's most damaging cyclone.[57] Cyclone Mahina in 1899 brought a storm surge to Far North Queensland reaching 13 m (43 ft) high, causing 400 deaths and making it the worst natural disaster to befall Australia.[58] ACER Aspire 9304WSMi CPU Fan

Cyclone Larry struck North Queensland and passed over Innisfail in 2006 causing damages estimated at A$1.5 billion but no lives were lost. Cyclone Yasi caused severe flooding and had a total estimated cost of A$3.5 billion making it the second most costliest cyclone to strike Australia.

Blizzards are not common in mainland Australia, but occur frequently in the Snowy Mountains in New South Wales and Victoria.HP 610773-001 CPU Fan

When blizzards do occur, they can affect the Tasmanian Highlands and, particularly, Mount Wellington, which towers over the Tasmanian capital Hobart. Blizzards do not affect any major towns or cities, because there are no populated areas located in the mountains except for the ski resort towns of New South Wales and Victoria.

A dust storm or sandstorm, a meteorological phenomenon common in arid and semi-arid regions, IBM ThinkPad R50p 1830 CPU Fan

arises when a gust front passes or when the wind force exceeds the threshold value where loose sand and dust are removed from the dry surface. Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another.

The term sandstorm is usedmost often in the context of desert sandstorms, especially in the Sahara, IBM ThinkPad T61 8898 CPU Fan

when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles moves closer to the surface. The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas.

Environmental issues in Australia describes a number of environmental issues which affect theenvironment of Australia.IBM ThinkPad R50p 2889 CPU Fan

There are a range of such issues, some of them relating to conservation in Australia while others, for example the deteriorating state of Murray-Darling Basin, have a direct and serious effect on human land use and the economy.

Many human activities including the use of natural resources have a direct impact on the Australianenvironment.

These issues are the primary concern of the environmental movement in Australia. IBM ThinkPad R50p 1830 CPU Fan

Climate change is now a major political talking point in Australia in the last two decades. Persistent drought and resulting water restrictions during the first decade of the twenty-first century are an example of natural events attributed by the mainstream media to climate change.[1][2][3][4]

Australia ranks within the top ten countries globally with respect to greenhouse gas emissions per capita.[5] IBM ThinkPad R50 1829 CPU Fan

The current federal and state governments have all publicly stated their belief that climate change is being caused by anthropogenic greenhouse gas emissions. Vocal minority groups within the population campaign against mining and coal-fired power stations in Australia, and such demonstrations are widely reported by the mainstream media. Similarly, vocal minority groups concurrently oppose wind energy schemes, despite being 'carbon neutral', on the grounds of local visual an.IBM ThinkPad R50P CPU Fan

d noise impact and concern for the currently high cost and low reliability of wind energy.[6][7][8]

Despite the publication of the Garnaut report and the Green Paper on the proposed Carbon Pollution Reduction Scheme, public belief in anthropogenic climate change has noticeably eroded following the leaking of e-mails from the University of East Anglia's Climate Research Unit.[9][10] IBM Thinkpad W500 CPU Fan

There is claimed to be a net benefit to Australia in stabilising greenhouse gases in the atmosphere at 450ppm CO2 eq[11] in line with the prevailing political stance. Public disagreement with this opinion is generally dismissed as expression of vested interests, for example from the coal industry.

Australia is a major exporter and consumer of coal, the combustion of which liberates CO2Compaq Presario CQ41-206TU CPU Fan

Consequently, in 2003 Australia was the eighth highest emitter of CO2gases per capita in the world liberating 16.5 tonnes per capita.[12] Australia is claimed to be one of the countries most at risk from climate change according to the Stern report.

Most of Australia's demand for electricity depends upon coal-fired thermal generation,[13]  SONY Vaio VPC-EB4X1E/BQ CPU Fan

owing to the plentiful indigenous coal supply, limited potential for hydro-electric generation and political unwillingness to exploit indigenous uranium resources (although Australia accounted for the world's second highest production of uranium in 2005 [14]) to fuel a 'carbon neutral' domestic nuclear energy program.

Conservation in Australia is an issue of state and federal policy. HP G62-374CA CPU Fan

Australia is one of the most biologically diverse countries in the world, with a large portion of species endemic to Australia. Preserving this wealth of biodiversity is important for future generations.

A key conservation issue is the preservation of biodiversity, especially by protecting the remaining rainforests. The destruction of habitat by human activities, including land clearing, remains the major cause of biodiversity loss in Australia. HP Pavilion dv5-1203eg CPU Fan

The importance of the Australian rainforests to the conservation movement is very high. Australia is the only western country to have large areas of rainforest intact. Forests provide timber, drugs, and food and should be managed to maximize the possible uses. Currently, there are a number of environmental movements and campaigners advocating for action on saving the environment, one such campaign is the Big Switch and I Love Earth. TOSHIBA Satellite L300 CPU Fan

Land management issues including clearance of native vegetation, reafforestation of once-cleared areas, control of exotic weeds and pests, expansion of dryland salinity, and changed fire regimes. Intensification of resource use in sectors such as forestry, fisheries, and agriculture are widely reported to contribute to biodiversity loss in Australia. HP G62-a10EJ CPU Fan

Coastal and marine environments also have reduced biodiversity from reduced water quality caused by pollution and sediments arising from human settlements and agriculture. In central New South Wales where there are large plains of grassland, problems have risen from—unusual to say—lack of land clearing. HP 535766-001 CPU Fan

The Daintree Rainforest, a tropical rainforest near Daintree, Queensland covering around 1200 square kilometres, is threatened by logging, development, mining and the effects of the high tourist numbers. Dell MF60100V1-Q000-G99 CPU Fan

Over a hundred species of fauna are currently under serious threat of extinction. The plight of some of these species receives more attention than others and recently the focus of many conservation organisations has been the critically endangered Northern Hairy-nosed Wombat, the endangered Tasmanian Devil,[16] Northern Tiger Quoll, South Eastern Red-tailed Black Cockatoo, Southern Cassowary, Tasmanian Wedge-tailed Eagle, Leadbeater's Possum and Southern Corroboree frog. DELL R859C CPU Fan

Australia has a poor record of conservation of native fauna. The extinction of Australian megafauna is attributed to the arrival of humans and since European settlement, 23 birds, 4 frogs, and 27 mammal species are also known to have become extinct.

One of the notable issues with marine conservation in Australia is the protection of the Great Barrier Reef. Toshiba Satellite A105-S2101 CPU Fan

The Great Barrier Reef's environmental pressures include water quality from runoff, climate change and mass coral bleaching, cyclic outbreaks of the crown-of-thorns starfish, overfishing, and shipping accidents.

While there have been no oil spill environmental disasters of the scale of the Exxon Valdez in the country, Australia has a large oil industry and there have been several large oil spills [1]. Spills remain a serious threat to the marine environment and Australian coastline. SONY Vaio VGN-FW140E CPU Fan

The largest spill to date was the Kirki tanker in 1991 which dropped 17,280 tonnes of oil off the coast of Western Australia.In March 2009, the 2009 southeast Queensland oil spill occurred, where 200,000 litres were spilled from the MV Pacific Adventurer spilling more than 250 tonnes of oil, 30 tonnes of fuel and other toxic chemicals on Brisbane's suburban beaches.ACER Aspire 5730Z CPU Fan

Premier Anna Bligh described the spill as "worst environmental disaster Queensland has ever seen".

A serious issue to the Australian marine environment is the dumping of rubbish from ships. There have been a number of cases,[19] particularly involving the navy of Australian and other countries polluting Australian waters including the dumping of chemical warfare agents. SONY Vaio VPC-EB4S1E/WI CPU Fan

Recently documented cases include the aircraft carrier USS Ronald Reagan in 2006 which was found to be dumping rubbish off the shores of Moreton Island.[20] In Victoria, a large number of toxic drums containing 1,2-Dichlorobenzene xylenol, a substance very toxic to aquatic creatures washed up on beaches during May 2009 presumably fallen off a passing container ship.HP Pavilion dv9580ed CPU Fan

Australia's geographical isolation has resulted in the evolution of many delicate ecological relationships that are sensitive to foreign invaders and in many instances provided no natural predators for many of the species subsequently introduced. Introduced plants that have caused widespread problems are lantana and the prickly pear bush. HP 538340-001 CPU Fan

The introduction and spread of animals such as the cane toad or rabbit can disrupt the existing balances between populations and develop into environmental problems. The introduction of cattle into Australia and to a lesser extent the dingo, are other examples of species that have changed the landscape. Toshiba Satellite L305D-S5934 CPU Fan

In some cases the introduction of new species can lead to plagues and the extinction of endemic species.

The introduced species red fox has single-handedly caused the extinction of several species. Tasmania takes the threat of red fox introduction so seriously that it has a government sponsored taskforce to prevent fox populations from taking hold on the island. SONY Vaio VGN-CR31S/P CPU Fan

In the prehistory of Australia the indigenous Australians used fire-stick farming which was an early form of land clearing which caused long term changes to the ecology. With European colonisation land clearing continued on a larger scale for agriculture - particularly for cattle, cotton and wheat production. Since European settlement a total of 13% of native vegetation cover has been lost. HP Pavilion dv5-1210et CPU Fan

The extinction of 20 different mammals, 9 bird and 97 plant species have been partially attributed to land clearing. Land clearing is a major source of Australia’s greenhouse gas emissions, and contributed to approximately 12 percent of Australia’s total emissions in 1998.

The consequences of land clearing include dryland salinity and soil erosion. These are a major concern to the landcare movement in Australia. SONY Vaio VGN-FW465J/B CPU Fan

The clearing of native vegetation is controlled by Federal laws (indirectly), State law and local planning instruments. The precise details of regulation of vegetation clearing differ according to the location where clearing is proposed.

Australia is one of the most urbanized countries in the world. Many Australian cities have large urban footprints and are characterised by an unsustainable low density urban sprawl. HP Envy 15 CPU Fan

This places demand on infrastructure and services which contributes to the problems of land clearing, pollution, transport related emissions, energy consumption, invasive species,automobile dependency and urban heat islands.

The urban sprawl continues to increase at a rapid rate in most Australian cities, particularly the state capital cities, all of which (with the exception of Hobart) are metropoleis. HP Pavilion dv7-1190er CPU Fan

In some centres, such as Sydney and Greater Western Sydney,[22]Greater Melbourne[23] and South East Queensland[24] large metropolitan conurbations threaten to extend for hundreds of kilometres and based on current population growth rates are expected to become megacities in the 21st century. Most Australian cities population growth is a result of migration in contrast to the Birth rate and fertility rate in Australia, which is contributing to the ongoing trend of urbanisation. Toshiba Satellite A105-S4074 CPU Fan

In recent years, some cities have implemented transit-oriented development strategies to curb the urban sprawl. Notable examples include Melbourne 2030,[25] South East Queensland Regional Plan and the Sydney Metropolitan Strategy.

There are also population decentralisation programs at state and federal levels aimed at shifting populations out of the major centres and stemming the drivers to rapid urbanisation.  IBM MCF-208AM05-1 CPU Fan

Albury-Wodonga was part of the federal government's program of decentralisation begun in the 1970s, which has at times had relocation policies for immigration. The Victorian government has run a decentralisation program since the 1960s, having had a ministerial position appointed and ongoing promotional and investment programs for stimulating growth in Regional Victoria.IBM MCF-217PAM05 CPU Fan

 HP GB0507PGV1-A CPU Fan


However policy has swung over the decades, primarily due to local development priorities and agendas and a lack of federal co-ordination to the problem.

The protection of waterways in Australia is a major concern for various reasons including habitat and biodiversity, but also due to use of the waterways by humans.

The Murray-Darling Basin is under threat due to irrigation in Australia, causing high levels of salinity which affect agriculture and biodiversity in New South Wales, HP Pavilion dv6-3385la CPU Fan

Victoria and South Australia. These rivers are also affected by pesticide run-off and drought.

Sustainable waste management is significant problem in Australia, and serious issues include large quantities of e-waste and toxic waste going into landfill. Australia does not have restrictions on the dumping of toxic materials that are common in other countries, such as dumping Cathode Ray Tubes which leech heavy metals into water catchments. HP Pavilion tx2510us  CPU  Fan

Due to the lack of sufficient sites for toxic waste disposal large quantities of toxic waste are trucked between states to remote dumping grounds or exported overseas in ships. HP G62-b55EV CPU Fan,HP Pavilion dv6-2145sf CPU Fan,HP Pavilion dv7-1120ew CPU Fan

Partager cet article

Repost 0
Published by batterys
commenter cet article