Australian Climate Change in the Last 50,000 years Essay -- Climate We

Who were the first settlers of Australia and when did they arrive? Both questions have yet to be answered 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 â€Å"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 â€Å"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... ...adal time scales. Its ecosystems â€Å"contain a large proportion of endemic (solely Australian) species, reflecting their long evolutionary history and isolation from other landmasses†Ã¢â‚¬â€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 Lamb, H.H. Climate, History, and the Modern World. 2 nd ed. New York: Routeledge, 1995. www.greenhouse.gov.au/science/guide/pubs/chapter1.pdf www.rsphysee.anu.edu.au/nuclear/news_events/mediarelease1.pdf www.wikipedia.com/wiki/Australia www.wrc.wa.gov.au/srt/publications/landscape/resource/climate.html