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Long term & short term effects of climate 2
 

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