Presentation on theme: "The Antarctic Going to extremes. What is the Antarctic? The area south of the Antarctic circle and around the south pole. –Below latitude 66° 33 39 south."— Presentation transcript:
What is the Antarctic? The area south of the Antarctic circle and around the south pole. –Below latitude 66° 33 39 south –Antarctic opposite to Arctic
Antarctic Circle CIA World Fact book image Antarctic circle
Which countries are closest to the Antarctic? http://www.worldatlas.com/webimage/countrys/an.htm
Daylight in the Antarctic At every point, 24 hours of continuous daylight as least once per year (midnight sun) –At every point, 24 hours of continuous darkness as least once per year (polar night) –Additional all light / all dark days as you go further south When is the shortest day in the year in your area? How long is it?
Antarctica Continent extending to the south pole, mostly inside the Antarctic circle 14.4 million square kilometers –5.4 million square miles –5 th largest continent (larger than Europe) –How does this area compare with the lower 48 states in the US? Highest average elevation of all the continents NASA composite photo
Its a hard place to live No bears No indigenous people Penguins Seals Whales Mosses Lichens Algae Scientists Whalers, in earlier times Emperor penguin chicks Cape fur seal
It is very cold and dry Colder than the Arctic –Higher elevation, often 3 km above sea level (much of Antarctica is a high plateau) Where in the US is the altitude this high or higher? How high is it at your school? –Arctic ocean warms the polar area somewhat –Lowest temperature ever recorded on earth, -89.2 ºC A frozen desert – dry as the Sahara Driest of all the continents –Less than 1 inch of annual precipitation in some areas –4 inches at the south pole –What is the annual average in your area?
The south pole The average winter temperature at the south pole is -59 ºC Warmest summer temperature at the south pole on record is -14 ºC –What is the typical temperature range in your area? http://astro.uchicago.edu/cara/vtour/pole/poles/
Antarctica ice sheet 98% covered by ice, about 2100 meters (7000 feet) thick 90% of worlds ice, 70% of worlds fresh water If it all melted, sea level would rise ~61 meters (200 feet) –Not too likely, since the average temperature is -37 ºC, and never above freezing most places
Warming and ice sheets Adjoining floating ice sheets might start to disintegrate with warming Icebergs could then break off the continental shelves Partially offset by increased snowfall with warming Perhaps eventual a few meter rise in sea levels
A mini-history of Antarctica 350 BC. Greeks invent idea to balance Arctic with opposite (anti) mass, Antarctic 1773. James Cook circumnavigates Antarctica 1819-1823. Whalers and sealers land 1840s. French, British, Americans sail continuous coastline and establish Antarctica as a continent
Mini-history, cotd. 1902. Captain Robert Scott, UK, fails to reach the south pole with his team 1907. Ernest Shackelton, UK, comes closer and turns back 1911. Norwegian Roald Amundsen is first to reach the pole; his party dies on return 1929. First flight over south pole (Byrd, US) 1956. First flight lands at the south pole (US) – first humans at pole since 1911 1957. 60 research stations established, 12 nations 1961. Antarctic treaty signed assuring peaceful uses
4 th International Polar Year (IPY) International effect to study physical, geological, and biological aspects of the polar regions March 2007 – March 2009 Antarctic research agenda –Sediment and ice core drilling to trace climate change –Subglacial lakes in Antarctica: liquid water under 3000 meters of ice!
Subglacial lakes High pressure and suitable temperatures make them possible –First suspected in 1950s –Radar, seismic data show over 140 exist –Lake Vostok is as large as Lake Ontario Research agenda –To understand the formation and evolution of subglacial lake processes and environments –To determine the origins, evolution and maintenance of life in subglacial lake environments Challenge: How can you do this through 3000 m of ice and not disturb possible organisms or introduce new ones?
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