25 January 2020 | New Scientist | 29Icy invention
Photographer Greg White
THE Himalayan desert of Ladakh
is home to this majestic tower of
ice, known as an ice stupa, after
the domed Buddhist buildings.
It is effectively an artificial glacier,
created by local people to store
water and designed to start
melting when they need it.
In winter, temperatures in
Ladakh rarely rise much above
-40°C, and can fall below freezing
even on summer nights. The area
receives little rain, so local people
rely on melting glaciers to obtain
water for irrigation and livestock.
But climate change has caused
the glaciers to shrink and the
flow of their meltwater to become
erratic. To get around this, in late
summer, local people catch glacial
meltwater in underground pipes.
The water is sprayed onto a domed
structure at night, where it freezes.
The ice stupa starts to melt in
March and will continue to do so
until around July, when rainfall is at
its lowest. Its conical shape shields
much of the ice from the sun. This
means the tower, which can reach
50 metres in height (see below),
melts slowly, feeding surrounding
streams. The following summer,
the cycle repeats. ❚
Jason Arunn Murugesu