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

1. Title:
   How to grow your own glacier - M Jackson
2. Description:

   View full lesson: https://ed.ted.com/lessons/how-to-grow-your-own-glacier-m-jackson

   In the 13th century, Genghis Khan embarked on a mission to take over Eurasia, swiftly conquering countries and drawing them into his empire. But, legend has it that there was one obstacle that even he couldn't overcome: a towering wall of ice, grown by locals across a mountain pass. M Jackson explores the ancient methods of growing glaciers and how they can be used to combat climate change.

   Lesson by M Jackson, directed by Artrake Studio.

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

    ¶

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

    ¶

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

    ¶

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

    ¶

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

    ¶

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

    ¶

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

    ¶

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