Predicting past climates
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Predicting past climates






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    Predicting past climates Predicting past climates Presentation Transcript

    • Predicting Past Climates
      By: Ronald, Salih, Anmol, Usman and Alex
    • What Is Climate?
      How Does Climate Affect Us?
      Introduction To Predicting Past Climates
      Table Of Contents
    • Climate is basically weather averaged over a period of time in any area.
      Climate deals with many factors, such as temperature, humidity, and wind.
      These factors determines a region’s Climate.
      The climate of a location is affected by altitude, closeness to a body of water, and latitude.
      What Is Climate?
    • Climate affects us, because it determines whether or not if we could grow plants.
      It also affects what our main diet includes, due to what grows in the climate we live in.
      It also affects what sort of activities that we can do.
      Climate can also change the types of clothes we wear. (EX: jackets in the winter)
      How Does Climate Affect Us?
    • Paleoclimatology is another word for the study of prehistoric climates.
      It can be studied from a regional to a global scale.
      Some methods for predicting past climates include:
      Studying glacial deposits
      Studying sedimentary structures
      Studying fossils
      By Predicting past climates we can know if the Earth’s climate follows a set pattern
      Introduction To Predicting Past Climates
    • Continental drift- as the continents move, the ocean currents and wind patterns change.
      Creation of mountains and landmasses have changed the climate.
      There have been cycles of hot and cold weather over the past 800 000 yrs or more
      Long term changes in the climate
    • MilutinMilankovitch created theories as to why there are climate cycles
      Three reasons:
      Eccentricity- shape of earth’s orbit changes from elliptical to circular due to Jupiter and Saturn's gravity.
      Tilt- earth’s tilt changes from 22.1˚ to 24.5˚ over 41000 yrs. Angle of tilt ∝ seasonal differences. Currently, angle is 23.5˚ and it is decreasing
      Precision of tilt (wobble)- the earth wobbles in a cycle of over 26000 yrs. The direction of tilt changes. The north star also changes over a few thousand years
      Climate cycles - Reasons
    • Proxy records are used to predict past climate.
      Proxy records are stores of info that we can measure that tell us what the past climate was like
      Scientist compare the proxy records with historical records over the past centuries
      This allow them to predict climate from the very distant past
      Clues to Past Climate
    • Air bubbles have been trapped in ice in Greenland and Antarctica for many millennia
      Scientists dig into the ice and retreat long cylinders of ice called ice cores
      The bottom of it can be very old
      The cores are cut into thin slices and tests are done to measure variuos gases
      The amount of carbon dioxide, methane and nitrous oxide is measured which shows how much of these gases were present at different times in the past
      Clue to Past Climate – Ice Cores
    • Oxygen tests are also done to see if the O₂ is heavy or light
      The more light oxygen is present, the colder the air was.
      Ice cores also give info on precipitation and volcanic eruptions
      As the temperature increases, the levels of greenhouse gases do too
    • Trees get a growth ring every year
      If the conditions are warm and wet, the ring will be thick. If the are cold and dry, the ring will be thin
      Some trees such as the bristlecone and California redwood live for many millennia
      Scientists get clues from both living and dead trees to get records of climate from the past 10 000 yrs
      Trees in Ontario have provided records for 2767 yrs
      Clue to Past Climate -Tree RIngs
    • Coral reefs also grow rings for each year.
      Scientists study the layers to determine the surface ocean temperatures when the layers were growing.
      Reefs such as the Great Barrier reef in Australia have provided info on ocean temperature from many centuries in the past
      Clue to Past Climate – Coral Reefs
    • Layers of soil and rock build up on the earth over time in which fossils and dead plants can be found
      Pollen grain fossils can be used to find out plants that grew in the past
      Fossils are also found on the ocean floor which can be used to predict ocean temperature in the past
      In caves, rocks are formed from dripping water. They form faster in wet weather so this info is used to measure past precipitation.
      Clue to Past Climate – Rock, Ocean Sediment and Caves
    • Adam-Carr, Christine. "Earth's Climate Change and Natural Change." Science Perspectives 10. Toronto: Nelson Education, 2010. Print.
      "Climate." Wikipedia, the Free Encyclopedia. Web. 16 Jan. 2011. <>.
      "Reading Past Climates From Ice Cores." Science Daily: News & Articles in Science, Health, Environment & Technology. Web. 16 Jan. 2011. <>
      Works Cited
    • Predicting past climate can be done using different sources: Ice cores, Tree rings, Coral reefs, rocks, sediments and caves.
      All these have helped scientists learn about past climates and how it has affected life at that time.