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

  • Long Term & Short Term Effects of Climate Change
    By: Sarah Ramanathan
    Keiran 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. 
    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.
    225 Million years ago: Pangaea (Permian period)
    Changes Due to Continental Drift
  • 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 and old mountain regions such as the 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 porduced 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 (page 349 of textbook)
    -warm interglacial periods occur every 100 000 years
    Interglacial Period - Time between ice ages when Earth warms up
  • Changes That Occur Over Hundreds Of Thousands Of Years: The 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
  • 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
  • In a cycle close to 42,000 years, Earth tilts back and forth on its axis from 22.1 degrees to 24.5 degrees
  • 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 & Keiran
  • 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.
  • Ocean Currents
    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
  • The global conveyor belt begins around the North Pole and then works its way down, traveling through all of the oceans before circling back
    Ocean currents can have a major effect on the weather
  • Air Currents
    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.
  • 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.
  • 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. "How does Ocean Temperature affect Air Temperature?" WiseGeek. Web. 10 Jan 2011.
    Capital Regional District. "Global Ocean Currents.". 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