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China
plans to prevent rain during the opening ceremonies of the 2008 Olympics
in Beijing. The process, called cloud seeding, works by firing silver
iodide into storm clouds in the days leading up to the event. The
Chinese government hoped it could essentially "use up" the existing
clouds and assure clear skies for the ceremony.
The country's been doing it for decades -- with positive results. But
another experiment in cloud seeding, on the other side of the Eurasian
land mass, didn't go so smoothly.
Following World War II, the British government was still looking at ways
to get a leg up over enemy militaries. The Nazis had come close to
destroying Britain, and the United Kingdom had developed a taste for
preparation. The British government looked to the skies for an
advantage. The Royal Air Force (RAF) began experimenting with cloud
seeding. By impregnating the clouds with the particles needed to create
a severe thunderstorm, the British could effectively thwart the movement
of troops and even literally rain out enemy advances. But the
cloud-seeding project went terribly awry.
It's not that the experiments with cloud seeding didn't work. It worked
too well.
In 2001, the British Broadcasting Corporation (BBC) investigated rumors
that the RAF had seeded the clouds over England. They turned up
first-person accounts of some of the pilots who were involved in a
top-secret mission called Operation Cumulus. During this August 1952
operation, RAF pilots flew above the cloud line, dropping payloads of
dry ice, salt and -- like the Chinese currently use -- silver iodide.
After just 30 minutes, rain began to fall from the infected clouds. At
first, the RAF pilots -- dubbed rainmakers by the press -- reputedly
celebrated their success. But within the week a deluge began. By the end
of the month, North Devon, an area of England near the site of the
cloud-seeding experiment, experienced 250 times the normal amount of
rainfall.
On August 15, 1952, the day the rain started, an estimated 90 million
tons of water coursed through the town of Lynmouth in just one day
[source: The Guardian]. Entire trees were uprooted, forming dams and
allowing the tide of the two rivers flowing through Lynmouth to grow
even stronger in force. Boulders were carried by the current, destroying
buildings and carrying residents into the sea. In all, 35 Britons lost
their lives that day as a result of the torrential rain. Britain's
Ministry of Defense maintains that it had not experimented with cloud
seeding prior to the Lynmouth incident.
China and Britain paint two versions of the same picture. On one hand,
the Asian nation has successfully created a cloud-seeding program.
They've managed to generate irrigation for arid croplands from the
ultimate source. But the British disaster shows the potential results of
toying with the forces of nature.
And still, we need water more than ever. Using explosions isn't viable
to produce water currently, and AquaMagic and Whisson's Windmill aren't
being produced on a large enough scale to help with the immediate need
for water. Water is a finite resource, and one life on Earth can't do
without.
Source: http://science.howstuffworks.com |
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