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Themes in World Regional Geography

Themes in World Regional Geography. Geo100 - Fall 2003 Julie Hwang Lecture #3. Outlines. Environmental Geography Landform Climates Vegetation Water resources Food resources. How is Earth’s surface shaped?. Jigsaw puzzle fit of South America to Africa Mid-Atlantic Ridge

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Themes in World Regional Geography

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  1. Themes in World Regional Geography Geo100 - Fall 2003 Julie Hwang Lecture #3

  2. Outlines • Environmental Geography • Landform • Climates • Vegetation • Water resources • Food resources

  3. How is Earth’s surface shaped?

  4. Jigsaw puzzle fit of South America to Africa • Mid-Atlantic Ridge • Himalaya Mountains

  5. Continental Drift • The continents are in constant movement resting upon the plates • Some 250 million years ago, continents were connected into one single landmass called Pangaea • Pangaea was later separated into continents in the present day

  6. Laurasia Pangaea Gondwanaland 180 million years ago 225 million years ago The present day 65 million years ago

  7. Continental Drift • So what drives continental drift? • Exchange of heat energy from the inner Earth • Described by Plate Tectonics theory

  8. Earth’s interior • Core • Mantle • Crust

  9. Plate Tectonics (solid) Plates (molten) Plates drift upon the asthenosphere

  10. Plate Tectonics Plates Convection cell Plates move relative to one another driven by convection cell

  11. Volcanoes Subduction zone Plate Tectonics • Convergent plate boundary

  12. Plate Tectonics – landforms shaped by convergent plate boundary

  13. Mid-Ocean Ridge Rift Valley Plate Tectonics • Divergent plate boundary

  14. Plate Tectonics – landforms shaped by divergent plate boundary

  15. Olduvai Gorge (Tanzania)

  16. Global tectonic plates

  17. Global earthquakes & volcanoes

  18. Plate Tectonics • Earth is made up of a large number of geological plates that move slowly across its surface • Explains the inner workings of our planet and many landforms in a global scale • Gives clues about the world distribution of earthquakes and volcanoes

  19. What determines climates?

  20. 1. Solar Energy Greenhouse effect

  21. 2. Latitude

  22. 3. Arrangement of oceans and continents • Land areas heat and cool faster than do bodies of water • Continentality • Maritime climates

  23. 4. Pressure & Wind patterns 40° N 20° N Equator 20° S 40° S

  24. World Climates

  25. Global Pressure Systems

  26. World Precipitation

  27. Climographs • Horizontal line show average high and low temperature in degree Fahrenheit. • Vertical bars show precipitation in inches. • For an entire year

  28. Köppen climate classification systems • A - Moist Tropical Climates • B - Dry Climates • C - Humid Middle Latitude Climates • D - Continental Climates • E - Cold Climates

  29. Climate Type (cont.) • Tropical (A) • Tropical rain forest (Af, Am) • Tropical savanna (Aw) • Dry (B) • Steppe (BS) • Desert (BW) • Temperate – Mild and rainy winter (C) • Mediterranean (Cs) • Humid subtropical (Ca) • Marine west coast (Cb)

  30. Climate Type • Temperate – Cold and snowy winter (D) • Humid continental, warm summer (Da) • Humid continental, cool summer (Db) • Subarctic (Dc) • Polar (E) • Tundra (ET) • Icecap (EF) • Highland (H)

  31. World Climate Regions

  32. Global Warming

  33. Increasing earth surface temperature

  34. Causes of Global Warming • Emission of anthropogenic (human-caused) greenhouse gases • Carbon dioxide (CO2) • Chlorofluorocarbons (CFCs) • Methane (CH4) • Nitrous oxide (N2O)

  35. Effects of Global Warming • Climate changes • Increase in global temperature • Rise of sea levels • Intensity and frequency of cyclones • Drought and flood • Shift in major agricultural areas • Depletion in the earth’s ozone layer (CFCs)

  36. International debate on limiting greenhouse gases • Rio de Janiero Earth summit (’92) • The first legal instrument addressing global warming was formulated • Kyoto protocol (’97) • 38 industrialized countries agree to reduce the emissions of major greenhouse gases below 1990 levels

  37. Conflict with economic growth • Fear that controls will constrain business, slow the economy, and increase the cost of living • U.S. more reluctant to comply than other nations

  38. World Vegetation

  39. Vegetation • Product of climate, geology, and hydrology • Influence on climate, geology, and hydrology • Human modification (eg. domestication, agriculture) • Threatened by global economy

  40. Biome (Bioregion) • Grouping of the world’s flora and fauna into a large ecological province or region • Closely connected with climate regions, but the linkage has got less clear since industrialization (eg. irrigation, domestication) • Globalization is having an impact on world bioregions

  41. Vegetation Type Tropical Tropical forest Savannas Deserts Grasslands: Mediterranean, Temperate Temperate Forests: Deciduous, Coniferous Tundra Icecap Dry, Temperate Temperate Polar, Highland

  42. Vegetation Type (cont.) • Tropical forests and Savannas • Mostly found in equatorial climate zones • Covers around 7% of the world’s land area • Deserts and Grasslands • large areas of arid and semi-arid climate that lie poleward of the tropics • Comprise one-third of the Earth’s land surface • Prairie: North American grassland • Steppe: shorter, less dense grassland found in Russia and Southwest Asia

  43. Vegetation Type • Temperate forests • Large tracts of forests found in middle and high latitudes • Two major tree types dominate: Coniferous and deciduous • In many regions, these forests have been cleared for agricultural purposes

  44. World bioregions

  45. Deforestation in the Tropics • Cutting-off of tropical forests in Africa, Latin America, and Southeast Asia • Caused by • International wood sales • Cattle grazing (demand for beef) • Settlement purposes

  46. Desertification in the Grasslands • A spread of desert-like conditions in Africa, Australia, and South Asia • Caused by • Poor cropping practices • Overgrazing • The buildup of salt in soils from irrigation • Climatic fluctuations

  47. Water Resources

  48. Water stress • Calculated from the amount of fresh water available per person • describes and predicts where water resource problems will be the greatest • Africa stands out as a region of high water stress

  49. Water stress in Africa and SW Asia

  50. Flooding • Cause the most deaths of all natural disasters (accounts for 50% of natural disaster-related deaths) • Caused by • Population growth (forced people to settle in low-laying delta lands subject to flooding) • Deforestation

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