Predicting past climates


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Predicting past climates

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