Get Help
YouTube

Got a YouTube account?

Νέο: ενεργοποιείστε μεταφράσεις και λεζάντες που δημιουργήθηκαν από θεατές στο κανάλι σας στο YouTube!

English υπότιτλους

← Urbanization and the future of cities - Vance Kite

Πάρτε τον Κωδικό ενσωμάτωσης
20 Γλώσσες

Showing Revision 4 created 01/22/2014 by TED.

  1. Today ,more than half of all people in the world

  2. live in an urban area.
  3. By mid-century, this will increase to 70%.
  4. But as recently as 100 years ago,
  5. only two out of ten people lived in a city,
  6. and before that, it was even less.
  7. How have we reached
  8. such a high degree of urbanization,
  9. and what does it mean for our future?
  10. In the earliest days of human history,
  11. humans were hunter-gatherers,
  12. often moving from place to place
  13. in search of food.
  14. But about 10,000 years ago,
  15. our ancestors began to learn the secrets
  16. of selective breeding
  17. and early agricultural techniques.
  18. For the first time,
  19. people could raise food
  20. rather than search for it,
  21. and this led to the development
  22. of semi-permanent villages
  23. for the first time in history.
  24. "Why only semi-permanent?" you might ask.
  25. Well, at first, the villages still had to relocate
  26. every few years
  27. as the soil became depleted.
  28. It was only with the advent of techniques
  29. like irrigation and soil tilling
  30. about 5,000 years ago
  31. that people could rely on a steady
  32. and long-term supply of food,
  33. making permanent settlements possible.
  34. And with the food surpluses
  35. that these techniques produced,
  36. it was no longer necessary for everyone to farm.
  37. This allowed the development
  38. of other specialized trades,
  39. and, by extension, cities.
  40. With cities now producing surplus food,
  41. as well as tools,
  42. crafts,
  43. and other goods,
  44. there was now the possibility of commerce
  45. and interaction over longer distances.
  46. And as trade flourished,
  47. so did technologies that facilitated it,
  48. like carts,
  49. ships,
  50. roads,
  51. and ports.
  52. Of course, these things required even more labor
  53. to build and maintain,
  54. so more people were drawn
  55. from the countryside to the cities
  56. as more jobs and opportunities
  57. became available.
  58. If you think modern cities are overcrowded,
  59. you may be surprised to learn
  60. that some cities in 2000 B.C. had population densities
  61. nearly twice as high as that of Shanghai or Calcutta.
  62. One reason for this
  63. was that transportation was not widely available,
  64. so everything had to be within walking distance,
  65. including the few sources of clean water
  66. that existed then.
  67. And the land area of the city
  68. was further restricted by the need for walls
  69. to defend against attacks.
  70. The Roman Empire was able to develop infrastructure
  71. to overcome these limitations,
  72. but other than that,
  73. modern cities as we know them,
  74. didn't really get their start
  75. until the Industrial Revolution,
  76. when new technology deployed on a mass scale
  77. allowed cities to expand and integrate further,
  78. establishing police,
  79. fire,
  80. and sanitation departments,
  81. as well as road networks,
  82. and later electricity distribution.
  83. So, what is the future of cities?
  84. Global population is currently more than 7 billion
  85. and is predicted to top out around 10 billion.
  86. Most of this growth will occur
  87. in the urban areas of the world's poorest countries.
  88. So, how will cities need to change
  89. to accommodate this growth?
  90. First, the world will need to seek ways
  91. to provide adequate food,
  92. sanitation,
  93. and education for all people.
  94. Second, growth will need to happen
  95. in a way that does not damage the land
  96. that provides us with the goods and services
  97. that support the human population.
  98. Food production might move
  99. to vertical farms and skyscrapers,
  100. rooftop gardens,
  101. or vacant lots in city centers,
  102. while power will increasingly come
  103. from multiple sources of renewable energy.
  104. Instead of single-family homes,
  105. more residences will be built vertically.
  106. We may see buildings that contain everything
  107. that people need for their daily life,
  108. as well as a smaller, self-sufficient cities
  109. focused on local and sustainable production.
  110. The future of cities is diverse,
  111. malleable,
  112. and creative,
  113. no longer built around a single industry,
  114. but reflecting an increasingly connected
  115. and global world.