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← How to grow your own glacier - M Jackson

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Showing Revision 2 created 03/07/2019 by lauren mcalpine .

  1. In the 13th Century,
  2. Genghis Khan embarked on a mission
    to take over Eurasia,
  3. swiftly conquering countries and drawing
    them into his expanding Mongol Empire.
  4. With his vast armies he became almost
  5. But, legend has it that there was
    one obstacle
  6. that even the impressive Khan couldn’t
  7. A towering wall of ice,
  8. grown by locals across a mountain pass
  9. to stop the Khan’s armies from
    invading their territory.
  10. No one knows how historically accurate
    that particular story is,

  11. but remarkably, it draws on fact:
  12. For centuries, in the Karakoram
    and Himalayan mountain ranges,
  13. people have been growing glaciers
    and using these homemade bodies of ice
  14. as sources of drinking water and
    irrigation for their crops.
  15. But before we get to that fascinating
  16. it’s important to understand the
    difference between
  17. glaciers that grow in the wild,
  18. and those that humans create.
  19. In the wild,

  20. glaciers require three conditions to grow:
  21. Snowfall, cold temperatures, and time.
  22. First, a great deal of snow falls and
  23. Cold temperatures then ensure that the
    stacked up snow
  24. persists throughout the winter, spring,
    summer, and fall.
  25. Over the following years, decades,
    and centuries,
  26. the pressure of the accumulated snow
  27. transforms layers into highly compacted
    glacial ice.
  28. Artificially growing a glacier,

  29. however, is completely different.
  30. At the confluence of three great
    mountain ranges,
  31. the Himalayas, Karakoram, and Hindu Kush,
  32. some local cultures have believed for
    centuries that glaciers are alive.
  33. And what’s more,
  34. that certain glaciers can have different
    genders including male and female.
  35. Local Glacier Growers ‘breed’ new glaciers
    by grafting together—or marrying—
  36. fragments of ice from male and
    female glaciers,
  37. then covering them with charcoal,
    wheat husks, cloths, or willow branches
  38. so they can reproduce.
  39. Under their protective coverings,
  40. these glacierets transform into fully
    active glaciers
  41. that grow each year with
    additional snowfall.
  42. Those then serve as lasting
    reserves of water
  43. that farmers can use
    to irrigate their crops.
  44. These practices have spread
    to other cultures,

  45. where people are creating their own
    versions of glaciers
  46. and applying them to solve serious
    modern challenges around water supplies.
  47. Take Ladakh, a high-altitude desert region
    in northern India.
  48. It sits in the rain shadow of the
  49. and receives on average fewer than ten
    centimeters of rain per year.
  50. As local glaciers shrink because
    of climate change,
  51. regional water scarcity is increasing.
  52. And so, local people have started growing
    their own glaciers
  53. as insurance against this uncertainty.
  54. These glaciers come in two types:
    horizontal, and vertical.
  55. Horizontal glaciers are formed when
    farmers redirect glacier meltwater

  56. into channels and pipes,
  57. then carefully siphon it off into a series
    of basins made from stones and earth.
  58. Villagers minutely control the release of
    water into these reservoirs,
  59. waiting for each new layer to freeze
  60. before filling the basin
    with another wave.
  61. In early spring,
  62. these frozen pools begin to melt,
  63. supplying villagers with
    irrigation for their fields.
  64. Local people make vertical glaciers using
    the meltwater

  65. from already-existing glaciers
    high above their villages.
  66. The meltwater enters channels
    that run downhill,
  67. flowing until it reaches a crop site
  68. where it bursts forth from a pipe pointing
    straight into the air.
  69. When winter temperatures dip,
  70. this water freezes as it arcs
    out of the pipe,
  71. ultimately forming a 50 meter ice
    sculpture called a stupa,
  72. shaped like an upside-down ice cream cone.
  73. This inverted form minimizes the amount
    of surface area it exposes to the sun
  74. in the spring and summer.
  75. That ensures that the mini-glacier
    melts slowly
  76. and provides a reliable supply of water
    to feed the farmers’ crops.
  77. These methods may be ancient,

  78. but they’re becoming more relevant
  79. as climate change takes its
    toll on our planet.
  80. In fact, people are now growing their own
    glaciers in many regions beyond Ladakh.
  81. Swiss people, utilizing modern glacier
    growing technology,
  82. created their first stupa in 2016
    in the Swiss Alps.
  83. There are plans for over 100 more in
    villages in Pakistan,
  84. Kazakhstan, and Kyrgyzstan.
  85. Perhaps one day we’ll be able to harness
    our homegrown glaciers
  86. well enough to build whole walls of ice–
  87. this time not for keeping people out,
  88. but to enable life in some of the planet’s
    harshest landscapes.