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Title:
How to grow your own glacier - M Jackson
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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.
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Speaker:
M Jackson
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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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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.
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