-
Title:
How to grow your own glacier - M Jackson
-
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.
-
Speaker:
M Jackson
-
In the 13th Century,
-
Genghis Khan embarked on a mission
to take over Eurasia,
-
swiftly conquering countries and drawing
them into his expanding Mongol Empire.
-
With his vast armies he became almost
unstoppable.
-
But, legend has it that there was
one obstacle
-
that even the impressive Khan couldn’t
overcome:
-
A towering wall of ice,
-
grown by locals across a mountain pass
-
to stop the Khan’s armies from
invading their territory.
-
No one knows how historically accurate
that particular story is,
¶
-
but remarkably, it draws on fact:
-
For centuries, in the Karakoram
and Himalayan mountain ranges,
-
people have been growing glaciers
and using these homemade bodies of ice
-
as sources of drinking water and
irrigation for their crops.
-
But before we get to that fascinating
phenomenon,
-
it’s important to understand the
difference between
-
glaciers that grow in the wild,
-
and those that humans create.
-
-
glaciers require three conditions to grow:
-
Snowfall, cold temperatures, and time.
-
First, a great deal of snow falls and
accumulates.
-
Cold temperatures then ensure that the
stacked up snow
-
persists throughout the winter, spring,
summer, and fall.
-
Over the following years, decades,
and centuries,
-
the pressure of the accumulated snow
-
transforms layers into highly compacted
glacial ice.
-
Artificially growing a glacier,
¶
-
however, is completely different.
-
At the confluence of three great
mountain ranges,
-
the Himalayas, Karakoram, and Hindu Kush,
-
some local cultures have believed for
centuries that glaciers are alive.
-
And what’s more,
-
that certain glaciers can have different
genders including male and female.
-
Local Glacier Growers ‘breed’ new glaciers
by grafting together—or marrying—
-
fragments of ice from male and
female glaciers,
-
then covering them with charcoal,
wheat husks, cloths, or willow branches
-
so they can reproduce.
-
Under their protective coverings,
-
these glacierets transform into fully
active glaciers
-
that grow each year with
additional snowfall.
-
Those then serve as lasting
reserves of water
-
that farmers can use
to irrigate their crops.
-
These practices have spread
to other cultures,
¶
-
where people are creating their own
versions of glaciers
-
and applying them to solve serious
modern challenges around water supplies.
-
Take Ladakh, a high-altitude desert region
in northern India.
-
It sits in the rain shadow of the
Himalayas
-
and receives on average fewer than ten
centimeters of rain per year.
-
As local glaciers shrink because
of climate change,
-
regional water scarcity is increasing.
-
And so, local people have started growing
their own glaciers
-
as insurance against this uncertainty.
-
These glaciers come in two types:
horizontal, and vertical.
-
Horizontal glaciers are formed when
farmers redirect glacier meltwater
¶
-
into channels and pipes,
-
then carefully siphon it off into a series
of basins made from stones and earth.
-
Villagers minutely control the release of
water into these reservoirs,
-
waiting for each new layer to freeze
-
before filling the basin
with another wave.
-
In early spring,
-
these frozen pools begin to melt,
-
supplying villagers with
irrigation for their fields.
-
Local people make vertical glaciers using
the meltwater
¶
-
from already-existing glaciers
high above their villages.
-
The meltwater enters channels
that run downhill,
-
flowing until it reaches a crop site
-
where it bursts forth from a pipe pointing
straight into the air.
-
When winter temperatures dip,
-
this water freezes as it arcs
out of the pipe,
-
ultimately forming a 50 meter ice
sculpture called a stupa,
-
shaped like an upside-down ice cream cone.
-
This inverted form minimizes the amount
of surface area it exposes to the sun
-
in the spring and summer.
-
That ensures that the mini-glacier
melts slowly
-
and provides a reliable supply of water
to feed the farmers’ crops.
-
These methods may be ancient,
¶
-
but they’re becoming more relevant
-
as climate change takes its
toll on our planet.
-
In fact, people are now growing their own
glaciers in many regions beyond Ladakh.
-
Swiss people, utilizing modern glacier
growing technology,
-
created their first stupa in 2016
in the Swiss Alps.
-
There are plans for over 100 more in
villages in Pakistan,
-
Kazakhstan, and Kyrgyzstan.
-
Perhaps one day we’ll be able to harness
our homegrown glaciers
-
well enough to build whole walls of ice–
-
this time not for keeping people out,
-
but to enable life in some of the planet’s
harshest landscapes.
English [en]
Czech [cs]
Persian [fa]