* By Dechen Palmo
By
Dechen Palmo
Due
to water scarcity in major Chinese cities, Chinese scientists are coming up
with different techniques to acquire more water to satisfy their growing demand.
According
to a recent news report published on 22 March, 2018 in South China Morning
Post, "China needs more water. So it's building a rain-making network
three times the size of Spain," China is testing a weather modification
system developed by the state-owned China Aerospace Science and Technology
Corporation. The scientists have designed and constructed chambers using
cutting-edge military rocket engine technology to develop this system. This is
a cloud seeding method to bring more rain on the Tibetan plateau.
Tibet
is the home of largest store of accessible
freshwater outside the North Pole and South Pole, it is also the source of the
six most important rivers of Asia. Since Tibet is self-sufficient in water,
there is no need for the Tibetan plateau to induce such artificial rain-making
system. These burners are set up by
Chinese on the Tibetan plateau to increase rainfall in order to feed the Drichu
(Yangtze) and Machu (Yellow), which are the lifeline of Chinese people.
So
far, according to the news, China has built over
500 burners on Tibetan mountains. Furthermore, they are planning to
build tens of thousands of more such burners. Cloud-seeding is a method used by
scientists to alter rainfall pattern. Water in clouds need to form into heavy
droplets to precipitate. But often, the droplets in the clouds are just too
small to precipitate. This technique involves an enormous network of fuel
burning chambers which burn solid fuel to produce silver iodide, a
cloud-seeding agent with a crystalline structure, much like that of an ice.
Image: Snowy hydro
These
chambers are installed high on the Tibetan mountain ridges facing the moist
monsoon from South-Asia. As wind hits the mountains, it produces an upward
draft and sweeps the particles into the cloud to induce rain and snowfall. This
practice is not new and it is used in many countries. Even Beijing famously
used it during the Olympics in 2008. But the matter to be concerned about is
that the Chinese government is considering setting up what would be the world's
largest cloud-seeding operation and keep these chambers operating in a
near-vacuum conditions for months, or even years, without requiring maintenance
on the Tibetan plateau.
Other
cloud-seeding methods such as using planes, cannons and drones to blast silver
iodide into the atmosphere won't have much
environmental impact as the process of "blast" is for a short
duration and induce rain only when it is required. But the type of chambers
built on the Tibetan plateau that operate for months and years might have more
impact over other methods. This cloud-seeding technique sounds
good in theory, but the question is, does the technique work and what would be
the long-term effects on the Tibetan plateau?
Whether
cloud-seeding is a sustainable method is a controversial subject. A study in
2016 by the Wyoming Weather Modification Pilot Programme found that, although
the technique can increase precipitation if wind and other conditions are
ideal, it cannot do so reliably over a long period or on a large scale. Much of
the literature on this substantiate that not only does cloud-seeding fail to
achieve the desirable effect, it also could yield harmful consequences. Some of
these consequences include rain suppression, flood, tornado and silver iodide
toxicity.
In
Australia, scientists consider three or five years to be the bare minimum
period required to obtain a reliable data from the area of seeding trial. However, Australia has stopped cloud-seeding
due to environmental reasons.
The
Tibetan plateau is very fragile and any weather modification could be fraught
with unintended consequences. Before tens of thousands of chambers are to be
built at select locations across the Tibetan plateau, the Chinese government
should wait for at least three to five years to get reliable data
from these 500 burners which have already been set up. They also should carry
out a thorough scientific study of its use and conduct an Environmental Impact
Assessment (EIA) before giving the green light to such project.
*The author is an environment Research Fellow at the Tibet Policy Institute
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