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  1. 1. Global Environmental Change Climate Change, Global Warming… … what’s going on?
  2. 2. What is Climate? <ul><li>Climate = the average and variations of weather over a long period of time (~30 years) </li></ul>Above: Global average for atmospheric water vapor.
  3. 3. What is Weather? <ul><li>Weather = all natural phenonmena within the atmosphere at a given time (hours to days) </li></ul>
  4. 4. What is Science? <ul><li>Science is the search for knowledge </li></ul>The lunar cycle The extent of snowfall as the seasons progress from Summer into Winter and then back to Summer again.
  5. 5. How do these combine? <ul><li>Used to understand the physics, chemistry and biology of the Earth. </li></ul>Science is the search for knowledge The Nitrogen Cycle The Water Cycle
  6. 6. <ul><li>The Earth has many different systems that interact with each other in different ways. </li></ul>The Climate System Land Oceans Atmosphere Biosphere Ice
  7. 7. Modern Climate Systems <ul><li>Atmospheric circulation </li></ul>Sunlight
  8. 8. Modern Climate Systems <ul><li>Atmospheric circulation </li></ul>H.C. F.C. P.C.
  9. 9. Modern Climate Systems <ul><li>Ocean circulation </li></ul>The Great Ocean Conveyor Sinking cool water, rising warm water and wind help to form global ocean current systems.
  10. 10. <ul><li>Atmosphere and Greenhouse Effect </li></ul><ul><ul><li>The Earth’s atmosphere keeps it around 30°C warmer than it would otherwise be. </li></ul></ul><ul><ul><li>This is the Greenhouse Effect </li></ul></ul>Modern Climate Systems
  11. 11. What is the Greenhouse Effect? cc. Robert A. Rohde (Global Warming Art) cc. Robert A. Rohde (Global Warming Art) The temperature of the Earth depends on the amount of energy we receive from the sun versus the amount of energy lost back out to space.
  12. 12. Past Climate Systems <ul><li>How do we know about climate systems in the past? </li></ul>
  13. 13. Past Climate Systems <ul><li>1. Early human record </li></ul>Tourism NT Rock paintings provide evidence of fertile Sahara region (now desert) 6,000 years ago. cc. W.V. Bailey
  14. 14. Past Climate Systems <ul><li>2. Geomorphology </li></ul>Above: A “U” shaped valley shows that it was formed by a glacier. River deltas show where rivers entered the ocean or a lake.
  15. 15. Past Climate Systems <ul><li>3. Geological record </li></ul>Drilling into the ground can recover rock layers that record what conditions were like when the rock was deposited. Fossils preserve evidence of past life.
  16. 16. Past Climate Systems <ul><li>4. Ice cores </li></ul>GISP2 ice core at 1837m depth with clearly visible annual layers. Ice cores can preserve seasonal layering. Studying the chemistry of each layer can give clues about climate change.
  17. 17. Practical Exercise Climate Change: What can I do?
  18. 18. Is the Climate Changing?
  19. 19. What is Climate Change? <ul><li>Records change over decades to millions of years </li></ul>
  20. 20. What are the current climate trends? cc. Robert A. Rohde Global temperature for the last 150 years
  21. 21. What are the current climate trends? cc. Robert A. Rohde
  22. 22. Looking further into the past… cc. Robert A. Rohde Global temperature for the last 1000 years
  23. 23. Looking further into the past… cc. Robert A. Rohde Global temperature for the last 450,000 years
  24. 24. Looking further into the past… cc. Robert A. Rohde Global temperature for the last 500 million years
  25. 25. Anthropogenic Influence <ul><li>Fossil fuel </li></ul><ul><li>Aerosols </li></ul><ul><li>Cement manufacture </li></ul><ul><li>Land use </li></ul><ul><li>Livestock </li></ul>cc. Robert A. Rohde
  26. 26. Future predictions… <ul><li>Based on no changes in emissions (“business as usual”) </li></ul><ul><li>The UK would be 2-3.5°C hotter on average. </li></ul>cc. Robert A. Rohde
  27. 27. What does it all mean? <ul><li>Sea level rise </li></ul><ul><li>More extreme weather </li></ul><ul><li>Changes in precipitation </li></ul><ul><li>Spread of disease </li></ul>cc. Robert A. Rohde
  28. 28. Questions to be answered… <ul><li>How fast will the sea level rise? </li></ul><ul><li>How much warmer will it get? </li></ul><ul><li>When will the Arctic Ocean be ice-free? </li></ul><ul><li>Will the water cycle accelerate? </li></ul><ul><li>Are climate extremes increasing? </li></ul><ul><li>Will there be abrupt changes? </li></ul>
  29. 29. Science can provide knowledge… … We all have to provide the solutions.