Saturday, January 15, 2011 2:20:08 PM
"Perfect Actions"
Think You Might Escape?
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After Effects of a Limited Nuclear War
Think
you might escape the aftereffects of a limited nuclear
war that happens on the other side of the globe
from you? Think again.
Imagine that the long-simmering conflict between
India and Pakistan broke out into a war in which
each side deployed 50 nuclear weapons against the
other country’s megacities. Karachi, Bombay, and
dozens of other South Asian cities catch fire like
Hiroshima and Nagasaki did at the end of World War
II.Beyond the local human tragedy of such a situation,
a new study looking at the atmospheric chemistry
of regional nuclear war finds that the hot smoke
from burning cities would tear holes in the ozone
layer of the Earth. The increased UV radiation resulting
from the ozone loss could more than double DNA damage,
and increase cancer rates across North America and
Eurasia."Our research supports that there would
be worldwide destruction," said Michael
Mills, co-author of the
study and a research scientist at the University
of Colorado at Boulder. "It demonstrates that a
small-scale regional conflict is capable of triggering
larger ozone losses globally than the ones that
were previously predicted for a full-scale nuclear
war."
modeling
shows that the entire globe would feel the repercussions
of a hundred nuclear detonations, a small fraction
of just the
U.S. stockpile. After decades of Cold War research
into the impacts that a full-blown war between the
Soviet Union and the United States would have had
on the globe, recent work has focused on regional
nuclear wars, which are seen as more likely than
all-out nuclear Armageddon. Incorporating the latest
atmospheric modeling, the scientists are finding
that even a small nuclear conflict would wreak
havoc on the global environment (.pdf)
— cooling it twice as much as it’s heated
over the last century — and on the structure
of the atmosphere itself.
Mills’ work, which appears online today in the Proceedings
of the National Academies of Science, used a
model from National Center for Atmospheric
Research to look at the impact of throwing 5 million
metric tons of black carbon, or soot, into the atmosphere.
He found that when a cluster of cities are burning
together, they end up creating their own weather,
pumping soot 20,000 feet into the atmosphere. Once
there, sunlight would heat the smoke, and drive it
up 260,000 feet above the earth’s surface.Along
the way, the hot soot would cause a variety of atmospheric
changes with a net result of huge reductions in ozone,
which in the stratosphere serves as sunblock for the
earth. In the middle latitudes, the researchers found
the ozone layer would be reduced by 25 to 45 percent,
with the polar regions losing 50 to 70 percent of
their ozone coverage. This thinning is known as a
"hole" in the ozone layer, and would be many times
the size of the famed
hole over Antarctica.According to research
cited by the paper, the increase in ultraviolet light
falling to earth at the 45-degree latitude — a
little south of Portland, Oregon — would cause
damage to DNA to increase 213 percent.
"It
would have a dramatic effect on skin cancer and cataracts
and be very damaging to crops and ecosystems," Mills
said.
The
reduced levels of ozone would persist for five years,
with substantial reductions in ozone continuing for
another five years after that.
Even
if the cause of the war were local, its impacts would
be felt across the globe.
"Pretty
much everywhere [would be] affected," Mills concluded.
Photo:
A nuclear bomb is detonated in a test blast at Mururoa
atoll, French Polynesia, in 1971./Associated Press
∞
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