World Weather, Climate, and Society Projects |
Melbourne, Australia Sarah Dunham, Daniel Lake, Austin Slack Australia ’s population can be divided into three distinct groups. Aboriginals who we re thought to have arrived on the continent via land bridge first populated the continent during the last ice age. In 1788, the first permanent population of European settlers arrived off the coast of Sydney. (See the section on History for more information.) Contact bet we en these two distinct and at times oppositional groups caused a third population of international and multi-cultural people to evolve. Climate influenced each of these groups in unique ways. Climate and Aboriginal Life All Aboriginal communities are semi-nomadic hunters and gatherers, although each family group has its own defined space. The amount of space for each group depends on the surrounding climate. Those d we lling in the desert may have as much as 100,000 square kilometers while a group on the coast may only have 500. Climate plays an important role in how each group interacts with the land they d we ll on. During drought, Most of the year aboriginals lived and moved in small family groups to maximize their use of the land. Once a year or so, large groups (500 or more) would get together for social, ceremonial, and trade purposes. Usually, these gatherings we re centered on hunting or fishing expeditions. Aboriginal life changed drastically, becoming more Europeanized, when the British colonized the continent in the late 1780s. Climate and its influence on Colonial Life Agriculture is still a major part of the Australian economy. Wheat is one of the biggest crops in Australia; barley is also a major crop on the we stern end of the continent. Most cereal varieties are planted in mid-May, just after the we t season ends. Natural rainfall must be maximized since most of the growing is done in the dry season. Farms use floodwater to supplement regular watering patterns and to help recharge regular water resources. Climate and Today’s Multi-Cultural Life
Bibliography The Climate of Australia When looking at the climate of Australia, we can break up the continent into three basic areas of climate. The tropical region containing the northern peninsulas of Australia, as well as the city of Darwin, is hot and extremely wet. Average maximum temperatures range from 30 - 39°C with an average annual rainfall of up to 400 cm. The tropical north is covered with rainforests and is regularly hit by tropical monsoons, hence the extreme amount of precipitation. Secondly, the central deserts and grasslands cover over seventy percent of the inland and receive the least amount of rain, from 12 to 100 cm annually. The maximum temperature ranges from 24°C in the southern deserts to over 36°C in the northern grasslands. This enormous section of Australia is usually referred to as the “Outback” and is not densely populated. The third and most heavily-populated climate area is the temperate south and southeast. The big cities in Australia – Melbourne, Sydney, Canberra, Brisbane and Perth – are all located in the south, and all in the southeast except for Perth. We will focus on the southeastern coastal area when talking about this temperate climate zone, as the vast majority of Australians live in this area. The climate here is very moist and mild; although not as wet as the tropical north, receiving anywhere from 50 to 320 cm of rain annually, but much wetter in comparison to the Outback. The average maximum temperature in the southeast ranges from 12 to 27°C, which is more livable compared to the rest of the continent. To understand just how these climate zones function, we must look at the subtropical high that exists in the southern “horse latitudes” of around 30°S. The Subtropical High Pressure Belt Although the subtropical high pressure belt is generally centered over Australia, it shifts from season to season. The high pressure belt causes many changes in weather; from October to March the belt is in the south, carrying moisture from the Pacific into the temperate area in the southeast. During the winter, the belt shifts northward, increasing the amount of precipitation in the tropical regions of the north. When the high pressure system shifts north, the south is hit strongly by westerly winds and heavily precipitating cold fronts, characterizing the southern winter. The summers in southern Australia are dry and hot and distinguished by breezes off the coast. The tropical region of the north, however, experiences frequent monsoons in a very wet summer. Northwesterly winds bring moisture from the sea, causing rain and thunderstorms. A strong monsoon season may increase precipitation further south if a powerful tropical cyclone carries enough moisture over the inland. The northern winter is much more mild and dry as the high pressure belt shifts northward, causing less cloud cover and precipitation. El Nino and Drought Drought is commonplace in Australia; since 1972 only four years – 1974, 1984, 1989, and 2000 – have passed almost completely drought-free. Drought is defined by a water shortage in which for three months or more, an area receives less than 10% of the average rainfall. The causes of drought vary from year to year, but the primary cause in Australia has been El Nino. El Nino is defined by the warming of Pacific Ocean waters which move easterly, causing less moisture to be picked up by weaker trade winds that carry to Australia. Primary convection also migrates from the Australian/Indonesian region out into the Pacific Ocean, drying out the heavily precipitated-upon area of the southeast, while causing more storms on the ocean. El Nino has been recorded as far back as the 1500’s, however it really began to affect the weather in the 1970’s and 1980’s, peaking in 1982 when the sea west of Peru was four degrees warmer than average. Over the last three decades, we have seen droughts in Australia with great consistency, usually appearing every two to three years, lasting for at least one full year. The period from 1980 to 1983 was particularly filled with drought, clearly relating to the intense period of El Nino as mentioned before. This drastic increase in drought is certainly due to El Nino, which has increased in its effects over the last few decades. The effects of drought in Australia have been devastating over the last century. From 1895 through 1903 the number of sheep was halved and forty percent of all cattle were lost; this was the most destructive drought in terms of stock losses in history. From 1911 to 1916, 19 million sheep and two million cattle were lost; from 1939 to 1945, almost 30 million sheep were lost due to drought. From 1958 to 1967 we saw the longest drought ever in central Australia, causing damaging losses to sheep, wheat and farm income. The 1982 to 1983 drought was the most intense in terms of areas affected. An estimated $3 billion in damages was assessed due to losses in stock, crops, industries and drought relief. The regularity of the seasons in Australia has been thrown off by drought caused by El Nino. Prior to the 1970’s, the droughts in Australia did not occur with the regularity they have in the past three decades. The intensification of El Nino, which many think has to do with increased pollution and other human influences on the environment, has created an almost constant state of drought in Australia. For the citizens of Australia, we can only hope that the global community can strive to treat the environment better, as the smallest detrimental actions can have far-reaching consequences when it comes to weather and society. Bibliography Glacial vs. Interglacial Australia: Australian Climate Change in the Last 50,000 years Who we re the first settlers of Australia and when did they arrive? Both questions have yet to be ans we red definitively. The most common view is that the Aborigenes’ ancestors came from southeast Asia more than 50,000 years ago (50,000 BP). That date is based on a few sites in northern Australia where thermoluminescence-dating—a technique for determining the time at which material was formed by measuring the light energy released when heating it—was used. Because a comparatively greater number of sites have been radiocarbon-dated to around 40,000 BP, ho we ver, some researchers have come to doubt the accuracy of the thermoluminescence technique (indeed, thermoluminescence dating of the Jinmium site in the Northern Territory improbably suggested human settlement as early as 120,000 BP). Given the dating-tools currently at the disposal of the natural sciences, the saftest bet is to infer that the first human population likely arrived in Australia somewhere bet we en 40,000 and 50,000 yeas ago (www.wikipedia.com/wiki/Australia). One point on which there is no disagreement is that the first settlers most likely arrived during the earth’s last glacial period when cooler temperatures and increased glaciation lent to oceanic recession. Because the lo we red sea level effectively “created great stretches of dry land almost linking Australia to Asia ”, it facilitated the migration of peoples to the Australian continent (Lamb, 112). Admittedly, there do seem “to have remained some open water straits which the people somehow managed to cross”, but the majority most likely traveled by land (112). One stretch of level terrain, for example, actually joined Australia with New Guinea and enabled humans to walk into Australia for thousands of years. Upon reaching the continent, most early Australian peoples—such as those living in the Great Australian Bight, for example—tended to settle on the coast. It was not (as it is today) the aridity of Australia’s interior that led these early Australians to settle in coastal regions, ho we ver; on the contrary, it was “the opportunities of catching fish in the estuaries and evaporating sea water to get salt to preserve the food they caught on land and in the water” (114). If the early Australians had settled as early as 40,000 BP, their offspring endured over 20,000 years of the earth’s last glacial period, whose coldest period—i.e., the Late Glacial Maximum—lasted no more than 5,000 years, from about 22,000 to 17,000 BP ( www.rsphysee.anu.edu.au/nuclear/news_events/mediarelease1.pdf). At peak glacial conditions, Australia would have been about 9 degrees Celsius colder than today’s averages; in addition, arid conditions would have extended across much of inland Australia, with dune fields covering about 30 per cent of the continent (Ibid). Indeed, the level of precipitation in general would have been significantly less than it is today: because the combination of (1) lower sea levels due to increased glaciation and (2) lo we r sea-surface temperatures would have effectively reduced the availability of warm shallow water, there would have been hardly anything from which atmospheric moisture could form and subsequently precipitate. It is important to note, however, that in some parts of Australia, even though rainfall was uniformly lo we r, there would have been more water in the landscape than there is now. Indeed, it is an interesting fact about Australia’s glacial climate that in spite of comparatively lo we r levels of precipitation than are seen today, temperate and lo we r latitudes such as regional New South Wales, we re covered by an “enormously greater extent of…lakes and inland seas” (Lamb, 112). Although Lake George, for example, is dry at present, it would have been 12 meters deep at the time of the Late Glacial Maximum. What explains this? On the one hand, it was “because of shifts in the main rainfall belts and the reduced evaporation resulting from lo we r temperatures than now and increased cloudiness” (112). On the other hand, it was because the Murray-Darling river system would have carried much greater quantities of floodwater, “fed by meltwater from thin but extensive snowfields”, which, in turn, would have lent “to a series of oases in a relatively arid countryside” and to a generally we tter Australia in general (www.rsphysee.anu.edu.au/nuclear/news_events/mediarelease1.pdf). Indeed, Lamb has gone so far as to argue that the most “general” conclusion to be drawn from pollen analysis, former lake-levels, and the like, with respect to the “moisture history” of Australia, is that throughout Australia, “many places we re we tter, and more consistently we tter, than they are today, and rainfall had been increasing both in the tropical and temperate regions” (Lamb, 139). As a matter of fact, starting around 13,000 years ago, the evidence suggests that the climate became gradually warmer and we tter for several thousand years thereafter. Eucalyptus pollen, for example, appears 9000 years ago; glacial ice vanished from Kosciusko, and trees began to appear. In addition, around 12,000 to 10,000 years ago, the aforementioned land-bridge linking the Australian continent to New Guinea eventually flooded to form the Gulf of Carpentaria; incidentally, the event was the likely basis Great Flood described in the Aboriginal myth of ‘dream time’ (www.wikipedia.com). Somewhere bet we en about 4000 to 2000 BP, ho we ver, (most likely 2500 BP) there was a dramatic turning point in Australia ’s climate (Lamb, 139). Since then, two trends have characterized the Australian climate. On the one hand, “there has been a recession of precipitation to present levels”—levels which are considered “intermediately favorable to vegetation communities”; on the other hand, there has been an increase in continental aridity, especially in the Australian interior (www.wrc.wa.gov.au/srt/publications/landscape/resource/climate). In its present state, Australia is a large ( total land area = 7.7 million square km), relatively flat continent stretching from the tropics to mid-latitudes, with relatively nutrient-poor soils, a very arid interior, and rainfall that varies substantially on seasonal, annual, and decadal time scales. Its ecosystems “contain a large proportion of endemic (solely Australian) species, reflecting their long evolutionary history and isolation from other landmasses”—except during the last glacial period (www.greenhouse.gov.au/science/guide/pubs/chapter1.pdf). While its population of 20 million is still concentrated on the continent’s coast, this is a different coastline than that on which early settlers made homes for themselves 40,000 years ago; moreover, since the period of British colonization, it is a different population too. Bibliography |
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aboriginals inhabiting the desert know where ALL the water holes are, what plants store water from deep underground, and animals they can eat to obtain water. Aboriginals are also aware of the natural cycles like seasons, migration patterns, growing seasons, and fire. This intimate knowledge of natural cycles allows them to maximize all the land has to offer. For example, aboriginals inhabiting Goulburn Island go to different places to gather turtles, bandicoots, goannas, geese, wild honey, or yams depending on the season. They know when the pee we e birds return after the we t season that the water lily roots are ready to eat. 
There was also an expansion of cultivation. Most of the continent is either too we t or too dry to sustain crops, so most of the agriculture is concentrated in southeastern and south we stern Australia, where the climate is we tter, in “The Wheat and Sheep Zone” indicated on the map in orange. 
Like many other countries, Australia has a diverse population hailing from all corners of the world. Climate is one of the selling points of the continent. The majority of we bsites relating to tourism list a pleasant climate and beautiful beaches as one of the selling points. Melbourne, where the we ather journal was based, is no exception. Originally, it was built around the Yarra River. Since building began Melbourne has steadily grown into one of the most meticulously designed cities on the continent. It encourages residents to be outside and active through an abundance of lush parks, gardens, and beaches. As a growing city, Melbourne is trying to reduce emissions from cars to improve air quality, encouraging residents to bike, walk, or carpool to work. 
Unfortunately, the continent is directly under the growing hole in the ozone layer. Australians have the highest incidence of skin cancer anywhere in the world. As a result, Australians are more concerned with sun exposure, UV index is a part of the daily we ather report, lifeguards we ar panama hats, long pants, and long sleeves, and jingles like, "Slip on a shirt, slop on sunscreen and slap on a hat, wrap on sunglasses" encourage citizens to be conscious about the dangerous effects of the sun. Overall, climate has influenced everyday Australian life since the settlement of the continent. Many of the original influences: where to live, where to gather, where to farm, and what to do in free time can still be seen today. Present climate change is as much if an influence as climate itself. Natural trends are changing so social life and tradition may change drastically in the next 100 years. 
