Notes from an emergency room doctor: Where once
the "Chicken Littles" of our world were
written off as comedic paranoids, today they hold
a prominent place in the world of politics and
science. Where once earthquakes, fires, and floods
were the bane of humanity, now we have to worry
about more cosmic catastrophes.
On July 20th, while Jupiter was being bombarded
by huge fragments of a comet, the House Science
Committee voted to require NASA to track any major
comets or asteroids that threaten to hit the earth.
The committee noted that an asteroid half a mile
in diameter crossed Earth's path in 1989, coming
within six hours of hitting. It was only discovered
after it whizzed by us. So, while Congress is
not suggesting any imminent threat of "world's
colliding," they want us to be prepared.
But the risk of cometary collision is not our
only threat from celestial destruction. Today,
there is a real danger to public health due to
Within the spectrum of heat and light that the
sun shines down upon us, there is ultraviolet
(UV) radiation. UV can disrupt DNA and protein.
But 20 to 50 km above the earth, a thin layer
of ozone in the stratosphere effectively absorbs
UV and protects plants and animals from its toxic
effects. Ozone is created when solar UV splits
a molecule of oxygen creating two reactive atoms.
If one of these atoms collides with a molecule
of oxygen (O2), a molecule of ozone (O3) is formed.
In the troposphere, that layer of atmosphere
closest to earth in which we live, ozone has a
different effect. There ozone combines with automobile
exhausts and industrial pollutants to form smog.
So ozone high above is good. And ozone lower
down is bad. What environmentalists and physicians
are concerned about is the fact that we're losing
the good ozone and gaining the bad.
Chloroflurocarbons from spray cans and refrigerants
have been especially responsible for depleting
the upper atmospheric ozone. This compound has
diffused into the stratosphere and chemically
broken down this "good" ozone layer.
In 1985, scientists discovered a hole in that
ozone layer that now has expanded from Antarctica
to the populated areas of the Northern Hemisphere.
More and more dangerous UV radiation is now
raining down upon us. UV causes skin dryness,
wrinkling, and premature aging. It causes sunburn
and as later consequence, skin cancer. There are
cosmetically disfiguring skin cancers like basal
cell and squamous cell carcinomas and life threatening
skin cancers like melanomas. The risk of these
cancers increases in proportion to total exposure
to UV radiation. With the depletion of the ozone
layer, skin cancer is predicted to increase into
the hundreds of millions of cases in the next
Cataracts, which account for half the blindness
in the world, will also increase with more UV
radiation. Our ability to fight to disease diminishes
because exposure to UV alters our cellular immunity.
UV radiation can also damage crops and bring on
global food shortages.
This hole in the ozone layer not only allows
dangerous UV radiation through where it can disrupt
our DNA and proteins but also allows UV to make
more ozone in our lower atmosphere which creates
more smog. And more smog translates into more
The good news is that there is an international
agreement that will phase out chlorofluorocarbons
by the year 2000. The bad news is that it will
take at least 100 years before the effects on
the ozone layer disappear. By then we can worry
about the comet that I'm sure is coming.
You're probably not happy to read about earthly
doom, comets colliding, and holes in the atmosphere.
Afterall, there's no place to hide. But just think
of the intelligent conversations you can have
with the "Chicken Littles" walking around
with placards reading "the end is near."