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Sci 10 Lesson 1 May 4  -  Natural Causes of Climate Change

Sci 10 Lesson 1 May 4 - Natural Causes of Climate Change






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    Sci 10 Lesson 1 May 4  -  Natural Causes of Climate Change Sci 10 Lesson 1 May 4 - Natural Causes of Climate Change Presentation Transcript

    • Homework from last class:
      • Complete Chapter 10 review worksheets
      • Study for Chapter 10 Quiz
      • Bring May 12 th Playland field trip forms and money ASAP!
        • Due date to bring in forms and money is Monday, May 9th
      • Read over class notes and check out the class blog: http://msoonscience.blogspot.com/
    • Chapter 10 Quiz
      • You will have ~15 minutes to write the quiz.
      • Please write your multiple choice answers at the top of the test in the space provided.
      • Good luck!
    • Natural Causes of Climate Change Chapter 11.1 pp. 464-480 Chapter 11.1 pp. 464-480
    • Climate
      • Climate: the average conditions of a region over ≥ 30 years.
        • Includes clouds, precipitation, average temperature, humidity, atmospheric pressure, solar radiation, and wind.
        • The size of a region can range from small (ex. an island) to large (ex. the entire planet).
          • Climate and geography combine to allow specific organisms to grow
      pp. 464 - 465
          • Biogeoclimatic zone: a region with distinct plants, soil, geography, and climate
          • Ex: BC has 14 distinct biogeoclimatic zones.
    • Past and Current Climate
      • Paleoclimatologists: people who study climates of the geological past
          • Fossils  show what kind of environment was present
          • Tree rings  show evidence of growing seasons
          • River sediments  reveal types of rainfall
          • Ice cores  show past air condition and composition
            • Gases trapped in the ice, specifically CO 2 ,
            • reveal long-term atmospheric levels.
            • Fossils and sediment evidence show Earth’s climate has often changed drastically in the past.
          • Ex: 21 000 years ago, most of Canada and northern Europe was under glaciers.
      pp. 466 - 467
      • Ice core data reveal CO 2 levels for the past 650 000 years.
        • Scientists have also tested levels of CO 2 in the atmospheric air for the past 50 years.
      pp. 466 - 467
    • Factors That Influence Climate:
      • 1) Composition of the Earth’s Atmosphere
      • Earth is a closed system.
        • System: a group of parts that function together
        • as a whole
        • Very little energy (except radiant energy)
        • enters or leaves the system.
          • Earth’s atmosphere is the outer boundary.
      • Greenhouse: a closed system that absorbs thermal energy.
      • Natural greenhouse effect: absorption of thermal energy by the atmosphere; allows for a narrow range of temperatures on Earth.
      • Greenhouse gases: gases in Earth’s atmosphere that absorb and trap radiation as thermal energy (ex: CO 2 )
          • The more greenhouse gases, the higher the temperature of our atmosphere.
      p. 468
      • 2) Earth’s Tilt, Rotation, and Orbit
      • Earth’s tilt is responsible for seasons in northern hemisphere.
        • Summer - tilted toward the Sun , decreasing angle of incidence .
        • Winter - tilted away from the Sun , solar radiation has a large angle of incidence.
          • Earth’s tilt: ~22.3º - 24.5º
          • The greater the tilt,
          • the more extremes in climate.
      • Earth also “wobbles” as it rotates on its axis.
        • Axis changes  changes angle of incidence of solar radiation.
      • Earth’s revolution around the Sun is elliptical, not circular.
        • Variation in the Earth’s orbit changes its distance from the Sun.
      p. 468 - 470
      • 3) The Water Cycle
      • Water cycle: system of water circulation on, above, and below Earth’s surface.
        • 70% of all greenhouse gases in the atmosphere is water vapour .
        • When temperature increases, more water evaporates.
        • Two effects of increased water vapour in the atmosphere:
        • 1) More solar energy may be absorbed by this greenhouse gas.
        • 2) More solar energy may be reflected back out to space and never reach Earth.
      p. 471 The water cycle stores and transfers large amounts of thermal energy.
      • 4) Ocean Currents
      • Convection currents in oceans move large amounts of thermal energy all around Earth.
        • Deep ocean currents (≥ 200 m) flow based on density differences.
          • They behave like massive convection currents, with warm water rising in the tropics and cold water from the higher latitudes replacing it.
      pp. 471 - 473 Deep-ocean currents move cold, salty water below the surface and warm, less-salty water near the surface.
      • Salinity of water also changes density.
        • Cold water (found at the poles) is more dense than warm water.
        • Salty water (found at the poles) is more dense than fresh water.
        • Large changes in ocean water density can reverse current direction.
      • Surface currents (0 - 200 m) are warmed by from solar radiation.
        • Upwelling occurs when cold, deep water rises into surface currents.
          • La Niña is an example of upwelling.
          • La Niña: cool water comes to the surface of the Pacific Ocean;
          • causes warm winters in southeastern North America , and cool winters in the northwest .
          • El Niño is the reverse.
          • El Niño: warmer water on the surface of the Pacific Ocean results in warm winters in the Pacific Northwest and in eastern Canada.
      pp. 471 - 473
          • Carbon cycle: maintains a balance of CO 2 in the atmosphere.
          • Carbon sinks: a body or process that removes CO 2 from the atmosphere and stores it. (Ex: plants, ocean, forests)
          • Carbon sources: a body or process that releases CO 2 into the atmosphere . (Ex. rock weathering, burning fossil fuels or trees)
      pp. 473 - 474
      • 5) The Carbon Cycle
      • Carbon dioxide is a very important greenhouse gas.
        • More CO 2 molecules than any other greenhouse gas (except H 2 O).
          • CO 2 traps infrared radiation from Earth’s surface, allows the average temperature of Earth to stay above freezing.
      • 6) Catastrophic Events
      • Catastrophic event: large-scale disaster
      • Large-scale disasters can quickly change atmospheric conditions.
        • Erupting volcanoes release ash and molten rock that absorb radiation.
          • Released water vapour and sulfur dioxide (SO 2 ) form sulfuric acid (H 2 SO 4 )  reflects solar radiation back into space.
      p. 475
        • Meteorites and comets are thought to cause dramatic changes.
          • Add dust, debris and gases in the atmosphere.
          • May be responsible for some of Earth’s largest extinction events.
          • Debris reflects and absorbs radiation, causing the atmosphere below to cool.
    • Homework for next class:
      • Complete Check Your Understanding questions on p. 481
      • #s 1-8, 10, 12-15
      • Bring May 12 th Playland field trip forms and money ASAP!
        • Due date to bring in forms and money is Monday, May 9th
      • Read over class notes and check out the class blog: http://msoonscience.blogspot.com/
    • Works Cited
      • Images taken from the following sources:
      • http://blog.2012pro.com/predictions/polar-ice-is-melting-at-an-accelerated-pace
      • http://www.flickr.com/photos/mike_smiths_flickr/2446977716/
      • http://www.arctic.noaa.gov/essay_krembsdeming.html
      • http://www.stelr.org.au/carbon-cycle/
      • P ower Point Credit:
      • McGraw Hill Ryerson, 2007.