Long term & short term effects of climate 2
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Long term & short term effects of climate 2

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Long term & short term effects of climate 2 Long term & short term effects of climate 2 Presentation Transcript

  • Long and Short Term Changes in Climate By : Sarah Ramanathan Keiren Alam Chantal Liu Manal Rahim
    • For the past millions of years, our climate has had many significant changes. 
    • Changes in Earth's climate are triggered by changes in Earth's  energy balance.   
    Introduction
    • Long term changes:
      • continental drift
      • changes in Earth's orbit
    • Short term changes:
    • Volcanic eruptions
    • Air and Ocean Currents 
  • Long Term Changes in climate (millions of years - hundreds of thousands of years) Chantal & Manal
    • Plate Tectonics = Theory of explaining slow movement of large plates of Earth's crust
    • Continental Drift - Theory that Earth's continents used to be one supercontinent named Pangaea.
    Changes Due to Continental Drift
    • 225 Million years ago: Pangaea (Permian period)
    • 200 Million years ago: Laragia and Gondwanaland (Triassic period)
    • 135 Million years ago: Jurassic period
    • 65 Million years ago: Creations period.
  •  
  •  
    • Continents move = ocean currents and wind patterns change
      • Affects heat transfer
    • Affects distribution of land mass
      • Nothern Hemisphere (includes Canada) has most land mass.
    • Fewer large bodies of water = coldest winters & warmest summers
    • More large bodies of water in Southern hemisphere = more moderate climate
    • Temperatures weren't like this in Permian period
    • More mountains (caused by movement of Earth's plates) affects Local & regional climates
    • Wearing of mountains over time can also cause regional climate change
      • These changes have occurred in Canada because we have new/old mountain regions (Rockies and Appalachians)
    • Scientists have found that over time the energy the Sun produces over time can also change
    • Changes of area cause complications in production of CO2
    • CO2 produced in volcanoes & mid-ocean trenches.
      • Lost by slowly being absorbed into oceans
      • Areas w/ high overall temperature most likely had greenhouse warming due to volcanic CO2
  • Long-Term Cycles in Climate
    • 20 000 years ago, Earth had last ice age.
    • Temp was 10 degrees lower than today
    • Canada covered in ice sheet 3 km thick
    • Sea levels dropped as oceans froze over
      • Land under oceans were exposed, revealing hidden bridges to continents
      • Animals crossed over to new habitats
    • Major changes in temp happen in regular cycles
  • Recurrence of Interglacial Periods and Ice Ages
    • Every 100,000 years, interglacial periods and ice ages occur
    • Ice age (glacial period): long term reduction of Earth’s temperature = glaciers and ice sheets covering Earth
    • Interglacial periods: period of warmer temperature that separates periods of time in an ice age
      • Interglacial periods involve movements of glaciers
    • Causes temperatures to keep rising and falling depending on whether glaciers are advancing or retreating
  •  
  • Why these Interglacial Periods &Ice Ages Keep Happening
    • Engineer/astronomer Milutin Milankovitch developed theory on reason for these climate changes
    • Earth’s orbit around sun changes on three main ways/cycles:
      • Eccentricity (changing shape) of Earth’s orbit
      • Earth’s Tilt
      • Direction (wobble) of tilt
    • Eccentricity of the Earth’s orbit
    • Shape of Earth’s orbit around sun changes
    • Goes from almost circular to more elliptical (flattened circle/oval-like)
    • Caused by Jupiter and Saturn’s gravities
    • Occurs approximately every 100,000 years
    • Earth’s current cycle is more elliptical (oval-like)
    • Earth’s Tilt
    • Earth’s current tilt = 23.5 degrees
    • Earth’s tilt is responsible for its changes in seasons
  • In a cycle close to 42,000 years, Earth tilts back and forth on its axis from 22.1 degrees to 24.5 degrees
    • Scientists believe that changes in Earth’s tilt are cause for glacial cycles occurring
    • When Earth’s tilt is larger (closer to its 24.5 degrees max):
      • Glaciations end
      • Causes warmer summers
    • Earth’s tilt currently decreasing
  • Direction (wobble) of tilt (Axial Precession)
    • In order to grasp the idea, think of a spinning top
    • As it spins, it wobbles around/changes direction while spinning on same point
    • Earth’s tilt is similar
    • As Earth’s spins on its axis, it slowly wobbles
    • The angle of its tilt remains approximately the same but its directions changes
    • Cycle of roughly 26,000 years
  •  
  • Short Term Changes in Climate (decades - thousands of years) Sarah & Keiren
  • Volcanic Eruptions
    • Volcanic eruptions can cause Earth’s climate to change temporarily
    • rocks, dust, and gases are sent out high into atmosphere.
  •  
  •  
    • Suns energy reflects back out to space (from sulfur dioxide particles)
    • Earth’s surface shaded.
    • Amount of cooling depends on amount of dust put in air, and time of cooling-on size of particles.
  • Changes in Sun’s Radiation
    • suns radiation amount drops, Earth gets less energy
    • (less heat = Earth cools down)
    • suns radiation higher = more energy
    • No scientific reason yet why radiation
    • and over shorter time scales.
    • Uneven heating of Earth causes convection currents that create prevailing winds and ocean currents.
    • Ocean currents have a strong effect on climates of nearby land
    • Ocean currents can be caused by winds
    • Cold ocean currents cool air above
    • Warm ocean currents heat air above
    Ocean Currents
  • Ocean currents can have a major effect on the weather The global conveyor belt begins around the North Pole and then works its way down, traveling through all of the oceans before circling back
    • Air on Earth's surface is in constant motion called air currents
    • Air currents affect air quality and ocean currents, and weather conditions
    • Air currents caused by three main processes:
      • temperature change
      • Impurities
      • pressure
    Air Currents
  •  
  • Thank You
  • Bibliography
    • Nelson Science Perspectives 10
    • Nelson Education Ltd.
    • 2010
    • Pages 348-353
    • < http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/climate.htm >.
    • Windows to the Universe
    • 2010 National Earth Science Teachers Association
    • 200-2011
    • http://www.windows2universe.org/earth/climate/cli_seasons.html
    • Woods Hole Oceanographic Institution
    • Shelley Dawicki
    • March 28, 2005
    • http://www.whoi.edu/page.do?pid=9779&tid=282&cid=3638&ct=162
    • Long term climate
    • hypertext   G. H. Rieke
    • http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/climate.htm
    • Pictures:
    • Long term climate
    • hypertext   G. H. Rieke
    • http://ircamera.as.arizona.edu/NatSci102/NatSi102/lectures/climate.htm
    • http://www.phy6.org/stargcc/Sconcat2.htm
    • http://room106vjh2.blogspot.com/2010_09_01_archive.html
    • Black, Ken. &quot;How does Ocean Temperature affect Air Temperature?&quot; WiseGeek. Web. 10 Jan 2011.
    • Capital Regional District. &quot;Global Ocean Currents.&quot;. Web. 10 Jan 2011.
    • Hayhoe, Christy, Douglas and Katharine. Energy Transfer within the Climate System: Air and Ocean Circulation . Perspectives 10. Canada: Nelson Eduacation Ltd, 2010. 344-348. Print.
    • Exploring the environment
    • Wheeling Jesuit University/NASA-supported Classroom of the Future
    • September 30, 2010
    • http://www.cotf.edu/ete/modules/volcanoes/vclimate.html