Ozone depletion is said by many to be the most serious environmental problem
that we must currently face. Ozone depletion may upset, perhaps irrevocably
the fragile balance of the entire global ecosystem. This depletion is such
a deadly threat due to the resulting increases in ultra violet radiation.
In 1990, an all party committee produced a report entitled "Deadly Releases -
CFC's". This report began with the following conclusion:
"We, the members of the committee, have reached one
overpowering conclusion - not just a consensus, but
a unanimous opinion - that ozone depletion is a
threat to the continuation of life on Earth."
Unfortunately, since the time of that release, things have only become worse.
Currently, the ozone layer has been depleted between 15% - 30%. The resulting
ultra violet radiation increases are the real threat. Scientist have
determined that for every 1% decrease in stratospheric ozone, there is a
corresponding 2% increase in ultra violet radiation. Currently, scientists
have determined that increased ultra violet radiation will have the following
effects:
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* AQUATIC IMPACTS *
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1. PLANKTON
UV radiation will decrease the productivity and distribution of plankton.
This would have a devastating impact on the entire aquatic food web due
to the fact that plankton is the basis of almost all animal life
in the oceans. Marine phytoplankton produces as much biomass as all the
terrestrial ecosystems combined. It is an essential ingredient in the
food chain, as well as being a major oxygen producer and carbon sink.
A decrease in distribution of plankton would throw the entire marine food
chain out of balance, and this would have serious repercussions on
terrestrial species, including humans. Recent studies in the Antarctic
have determined that there has already been a 12% decline in phytoplankton
productivity in regions beneath the ozone hole.
2. LARVAE
Marine larvae, including crab, shrimp and anchovies will be severely effected
by increased ultra violet radiation. These animals spend a large amount of
time near the surface of the water where ultra violet radiation can penetrate.
A decrease in marine larvae would also have an adverse impact on the
aquatic as well as the terrestrial ecosystems.
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* Terrestrial Impacts *
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1. PLANTS
UV radiation has been proven to decrease productivity of various plant
species, including human food crops. Wheat, rice, corn, soyabeans, peas,
and beans are all adversely effected by ultra violet radiation. A decrease in
productivity would severely disrupt the global supply of food for humans as
well as other animals.Elevated UV radiation can cause plants to bloom earlier
or later than normal, thus disrupting the pollination cycle. As little as 4
days of elevated UV exposure can initiate far-reaching changes in plants,
including size, height, shape, rate of growth and productivity. UV radiation
can also cause changes in plant molecules - including changes in the
composition of proteins, carbohydrates and amino acids, which may have a
substantial impact on nutritional values of food plants and human health.
Scientists have determined that a 1% reduction of ozone, produces a
1% reduction in the yield of soyabeans.Current research is underway to
genetically engineer species of plants that are UV resistant. While this
may save the human supply of food, it does not solve the problem for other
species. Moreover, natural vegetation does not have this option. It takes
decades years for a crop to develop a natural immunity, and scientists do not
believe that plants could adapt.
2. FORESTS
Recent research indicates that UV radiation adversely effects the growth
and development of seedlings. Also research indicates that the effects
of UV radiation may accumulate in trees and that increased UV radiation could
significantly reduce the growth of some tree species. It may well be that
unshaded seedlings will not be viable - under the levels of UV we are
predicted to experience this year and into the future. If the forests
are severely damaged by UV radiation, this will adversely effect and increase
the rate at which global warming will occur. With the loss of the marie and
the forest carbon sinks, global warming will occur at an unprecedented rate.
Fortunately, glass has been proven to protect trees from UV radiation but
this, as before, is not an option for natural tree species. Scientists have
also demonstrated that UV radiation is particulary effective in light induced
degradation of wood and plastic products. This degradation leads to
discolouration and a hazardous loss of strength.
3. TERRESTRIAL ANIMALS
Almost all terrestrial species (except nocturnal animals) will be effected
by increased UV radiation. UV causes cataracts, skin cancer and suppresses the
immune system. Most animals will be susceptible to these deadly effects. In
Australia, there are currently over 500 cases of feline skin cancer per year,
a few years ago there were almost none. The human race has already increased
the natural rate of extinction 1000 fold. If ozone depletion continues
our race will be responsible for increasing that figure even further.
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* HUMAN IMPACTS *
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Increased UV radiation will have a devastating impact on the human race
if current social and cultural patterns continue. Increased UV radiation
will promote skin cancer, damage our DNA, cause eye cataracts, and age-
related far sightedness. In addition,there is a growing body of research that
indicates that even slightly enhanced levels of UVB radiation "turn off"
part of the human immune system. UV induced immune suppression has
been confirmed in humans of all colour and skin pigmentation.
Dr. Ed DeFabo, of George Washington University, states that "relatively
low UVB irradiances appear sufficient to activate the immunosuppressive
mechanism." In essence, a brief exposure to elevated UVB radiation has the
effect of turning off the T-suppressor cell immune function for a period of
up to two weeks following the exposure. This would leave people open to
contracting a wide range of diseases while the immune function is suppressed.
Further research indicates that UVB radiation may stimulate the HIV virus,
causing a faster onset of AIDS. There is currently not enough evidence to
confirm the UVB risk to persons with HIV, but there is a definite correlation
with the onset of AIDS and the beginning of summer. An early epidemiological
study of the seasonality of AIDS by researchers at the U.S. Centre for
Disease Control found a definite 12% difference in AIDS diagnosis with the
peak in the summer (when there is the most exposure to ultra violet light),
and a trough in the winter. Fortunately, there are certain foods that can
boost the immune system and prevent immunosuppression. These foods include
raw garlic, ginseng, comfrey, and shitake mushrooms.
The UV rays from the sun also interact with certain drugs says Dr. John
Goldhar, head of dermatology at Toronto's Mount Sinai Hospital. The most
harmful reaction is known as photosensitivity. This is characterized by
a rash, redness or swelling, and can be a side effect of various medications
including antibiotics for chest or bladder infections, as well as certain
types of pills for diabetics. The real danger behind photosensitivity is
the fact that the skin will burn more quickly. For example, if it normally
takes two to three hours to burn in the sun, photosensitive skin would take
just 10 to 15 minutes. There are between 150 and 200 medications that react
with the sun's rays, so check with your doctor or pharmacist.
The sun also causes a variety of rashes and skin blisters. "Polymorphous
light eruption" is a relatively common rash caused by the sun. After exposure
to the sun for 15 minutes to an hour, itchy bumps develop and sometimes
blister. They disappear after two or three days out of the sun. However,
each time sun expose occurs, the bumps reappear. Another type of rash
caused by the sun is called "solar urticaria" (hives); it usually clears
up after an hour or two out of the sun. These rashes are UVA induced, therefor
many sunscreens won't prevent them. To prevent these rashes be sure to wear
a broad spectrum UVA/UVB sunscreen.
It is essential to keep young children out of the sun. Doctors believe
that we get up to 80% of our total UV exposure before the age of 18. And
new research indicates that skin cancer can be acquired after only one burn.
Infants under the age of one year should be kept out of direct sunlight at
all times. To protect children from the sun, they must be dressed in sun
hats, long-sleeved shirts and long pants. A broad spectrum sun screen should
be applied on exposed skin including cheeks, ears, nose and the top of the
feet. It is also important to be a good role model and always protect
yourself from the sun.
The best way to prevent an onset of a global UV induced epidemic, is to
change our current sun-worshipping behavior. We must drop our belief that
"the sun is good for you", and "to be healthy is to be tanned." We must
realize the dangers of sun exposure and change our existing attitudes.
We must cover up, and protect our bodies from the UV rays. And we must listen
to the scientific community, before it is too late. For more information
please contact the B.C. Atmosphere Caucus.