Carbon dioxide is an inert gas that has many
important uses by man and by nature. It is the key ingredient in carbonated
beverages and in fire extinguishers. Carbon dioxide also is a part of the
processes of photosynthesis and respiration. Many people overlook carbon
dioxide's role in nature. Some scientists believe that maintaining the
proper balance of carbon dioxide in the Earth's atmosphere is needed for
plant and animal survival. Too much carbon dioxide in the atmosphere has
been linked to global warming which has the potential to cause severe changes
in the Earth's weather patterns. Scientists argue whether man and all his
machinery are responsible for global warming or whether global warming
is a problem at all. The outcome of the debate will continue to have political
and economic effects in years to come. If as some scientists believe, recent
temperature increases are an indication of "Global Warming," carbon dioxide
and the carbon cycle will need to be studied as a possible cause.
CARBON DIOXIDE AND THE CARBON CYCLE
Properties and Forms
Carbon dioxide is an inert gas with no color, no odor and a slightly acid
taste. It has only two basic forms, a gas or a solid, usually called
"dry ice." In order for carbon dioxide to take a solid form it must
be cooled to a temperature of -78.5 degrees celsius. Dry ice
is used primarily as a refrigerant, but can also be used for special effects
"smoke". When heated, carbon dioxide's solid form sublimates back
into a gas, instead of melting into a liquid like water based ice.
This is why it is called "dry ice." In its pure form carbon dioxide
("CO2") is the combination of the molocule of carbon with two molecules
Carbon dioxide only takes two forms, but is produced in a variety of ways.
The burning of fossil fuels called "combustion" produces carbon dioxide
as a byproduct. One of the most common forms of combustion is the
one used in automobile engines, which produce carbon dioxide in the form
of exhaust. All living, breathing creatures produce carbon dioxide
through respiration. Respiration is the process in which air is inhaled,
oxygen is absorbed and carbon dioxide is exhaled as a waste product.
Other natural processes that produce carbon dioxide are fermentation and
decomposition. Fermentation involves the tranformation of organic
compounds and is the same process used to ferment grapes into wine.
Decompostion is the natural process where carbon based matter is reduced
to other elements. Both processes produce and give off carbon dioxide
into the atmosphere.
Like water, carbon dioxide has a natural cycle as it moves from and through
the land, sea and air. The carbon cycle referred to by scientists
explains and describes the natural movement of carbon dioxide between the
earth's elements. Carbon dioxide is in the earth's oceans, atmosphere
and the earth itself in the form carbon based matter. The earth's
oceans absorb much of the carbon dioxide and act as huge storage areas
for the CO2, especially at cooler temperatures. Oceans are sometimes
referred to as "carbon sinks." The oceans contain about 60 times
more carbon dioxide than the atmoshere. As the oceans are warmed,
carbon dioxide is released back into the atmosphere where it is used by
plants during the process of photosynthesis. Like water, carbon dioxide
is constantly in motion and nature has its own way of keeping the amount
of carbon dioxide in the atmosphere in balance. Some scientists now
believe that man and his machines may be throwing the carbon cycle out
of balance which may affect the earth's climate in the future.
II. USES AND FUNCTIONS OF CARBON DIOXIDE
has many useful functions in nature. One of carbon dioxide's most
important properties is its use by plants during the photosynthesis process.
During photosynthesis carbon dioxide is converted to energy by plants and
oxygen is produced as a byproduct. Through photosynthesis, plants
provide earth's airbreathing creatures, including humans, with the oxygen
Carbon dioxide is also in the blood system and helps stimulate breathing.
Carbon dioxide in the earth's atmosphere helps create and maintain the
earth's temperature. In the atmosphere, carbon dioxide allows light
from the sun to pass through, but traps and reflects some of its radiant
heat. This property, sometimes called the "greenhouse effect", allows
the earth's temperature to remain warm enough to support life. Some
scientists fear that increasing levels of carbon dioxide in the atmosphere
may create too much of a greenhouse effect, causing the earth's temperature
to rise and its weather patterns to be changed.
Carbon dioxide plays a big role in nature, but many humans depend on it
too. All carbonated drinks contain dissolved CO2 and for many people,
that is what makes them enjoyable. Carbonated drinks known as sodas
or pop are sold in retaurants all over the world. Soda or pop has
been part of the American lifestyle for over 100 years. Soft drinks
with dissolved carbon dioxide were first created in the early 1800's and
many of the same basic drinks are still enjoyed today.
Softdrinks are made by starting out with a company recipe of flavored syrup.
The syrup is then mixed with purified water and carbonated. It is
carbonated by adding carbon dioxide to the liquid under pressure.
Carbon dioxide gives the drinks it fizzy nature, helps enhance the taste
and helps prevent the drinks from spoiling. In carbonated beverages,
carbon dioxide is the essential characterizing ingredient. The only
thing that makes each softdrink unique is its flavoring and taste.
In addition to water, syrup or sugar and carbonation, many softdrinks also
contain caffeine and artificial colors. Some of the minor ingredients
include acidulants which add a tart taste, potassium, which adds a small
amount of nutrients, sodium and natural and artificial sweeteners.
The softdrink industry in this country and the world is enormous.
Carbon dioxide has more important uses than making pop fizz. Its
natural properties make it perfect in fire supression systems. Carbon
dioxide does not burn and when applied in pressurized form to fires, it
smothers the fire so it can't get any oxygen. Carbon dioxide is the
main component of fire extinguishers. Fire needs oxygen. Carbon dioxide
displaces oxygen used by fires and forces the fire to go out.
Carbon dioxide in different forms is also used in the baking process.
Ordinary baking powder creates a form of carbon dioxide (sodium bicarbonate).
Carbon dioxide is produced by yeast which is used to make bread and is
also used in washing soda. Carbon dioxide is not only essential to
nature, it has many man made uses as well.
The solid form of CO2 is "dry ice." Dry ice is a very unique refrigerant.
It stays cold much longer than frozen water and doesn't melt. Dry
ice is used for shipping refrigerated items that cannot get wet.
Instead of melting, dry ice simpy sublimates as it warms up. Dry
ice can also be used for refrigerated storage. Dry ice's effectiveness
of cooling is twice that of regular water based ice. It also produces
an inert atmosphere that lowers or inhibits bacterial growth and helps
prevent goods from spoiling.
III. CARBON DIOXIDE AND THE "GREENHOUSE EFFECT"
Carbon dioxide has the ability to trap and reflect certain types of light
and heat. The sun's light passes through the carbon dioxide in the
earth's atmosphere and then is trapped which raises the earth's temperature.
This process is similar to light passing through the glass of a greenhouse
that traps and creates heat and helps plants to grow. This process
in nature is called the "greenhouse effect." Some scientists believe
that increased burning of fossil fuels is releasing too much carbon dioxide
into the atmosphere which may increase the greenhouse effect.
If too much carbon dioxide is released, scientists believe the carbon cycle
can be thrown off balance and the earth's temperature will rise with potential
Global warming is one predicted result of the greenhouse effect caused
by increasing levels of carbon dioxide in the atmosphere. Scientists
have researched and measured significantly increased levels of CO2
in the atmosphere since the industrial revolution and also claim to have
measured an increase in the earth's average temperature over the same period.
This leads many scientists to conclude that man and carbon dioxide may
be responsible for "global warming." If warming trends continue,
some predict severe environment and weather changes.
The facts are that in the last 100 years, carbon dioxide in the earth's
atmosphere has increased by almost thirty percent. During approximately
the same time period the global surface temperature also has increased
by .5 to 1 degree Farenheit. The earth's sea levels have increased
by four to eight inches and some of the polar ice caps, especially in the
north have been melting. In the next 50 years some scientists predict
that the global surface temperature could possible rise 1 to 4.5 degrees
Farenheit and 2.2 to 10 degrees in the next century. If so, the earth's
sea levels could rise by as much as two feet. While these measurements
don't seem like much, even small variations in the earth's temperature
or sea levels can have severe effects in parts of the earth's climate.
Increased temperatures could cause increased evaporation and more rain
in parts of the world. Increased sea levels could cause flooding
in others causing large areas to become submerged. In general,
scientists alarmed by the effects of global warming believe climate changes
may lead to millions of acres of land turning into deserts which could
cause widespread hunger.
not all scientists believe global warming is a significant problem or that
it is created by man. Some say there may have been a slight increase
in the earth's temperature, but nothing abnormal, and that the predictions
of global warming are exaggerated. Others say that the earth is simply
going through natural climate changes caused by the end of an ice age or
the magnetic cycles of the sun. Today the "cause and effect" of global
warming is still hotly debated.
Increases in atmospheric
carbon dioxide are not the only explanation for global warming. Some
scientists believe that changes in the sun's brightness is a better explantion
for the slight warming of the earth's surface. The sun undergoes
magnetic cycles that last about 22 years. In those 22 years, the
sun reaches it's brightest stage (burns the hottest) and slowly gets dimmer
(and cools). Scientists measuring the sun's magnetic cycle
believe there is a close correlation between the sun's cycle and the earth's
temperature. The temperature rises slightly when the sun's cycle
is at its peak and cools slightly as it dims. The brighter the sun
burns, the higher the global surface temperature. Scientists tracking
the sun's cycle believe that there has not been a significant increase
in the earth's temperature when the natural effects of the sun are factored
out, or that the man-caused effects of any global warming are overstated.
If true, the human effects of global warming could be much smaller than
some scientists and politicians make it seem.
even more simple explanation for the earth's recent warming is natural
drought and climate changes. The earth may be going through a natural
warming stage as one more "ice age" ends. Scientists have measured
and predicted that the earth has gone through many warming and cooling
periods (ice ages) over time and there is no evidence that recent temperature
changes are abnormal. Today, while global warming has been studied
for some time, nothing is certain. Scientists will continue to theorize
about the cause, effects and solutions to global warming.
As of today,
global warming seems to be a fact, but its long term effects and man's
ability to control it are unknown. As a precautionary measure many
scientists believe that limiting the use of fossil fuels will somewhat
reduce or prevent the long term effect of global warming. Others
believe that humans don't significantly contribute to global warming and
reducing the burning of fossil fuel won't make a difference. There
are politicians on both sides as well. Clearly, reduction of processes
that release greenhouse gases such as carbon dioxide into the atmosphere
is one possible solution.
nations including the United States have tried to reduce the emissions
of greenhouse gases through a treaty called the Kyoto protocol, named after
the city in Japan where limits on emissions were discussed. Under
the Kyoto protocol nations agree to limit or reduce their emissions of
greenhouse gases. If adhered to, it is believed the levels of greenhouse
gases in the atmosphere will be significantly reduced. However, just
as scientists don't agree on the cause or threat of global warming, nations
have difficulty agreeing on how to reduce its effects. Many nations,
including the United States don't follow the limits set forth in the Kyoto
agreement because of its effects on the economy. Americans want to
continue to make, sell and drive their own cars.
Scientists are still researching the cause
and effects of global warming and whether carbon dioxide is a problem.
Carbon dioxide has many positive uses and some negative properties. Without
carbon dioxide there wouldn't be life on Earth, but too much carbon dioxide
created by man may increase its natural "greenhouse effect." Based on most
of the current research, the rise in the Earth's temperature is probably
caused in part by human created greenhouse gases. However, there are other
explanations that are being explored. Natural changes in climate from the
end of an ice age or the sun's normal cycles also may have impacts on the
Earth's temperature. Until more data is collected, humans have a responsibility
to avoid harming the planet by things within their control. Carbon dioxide
may be great in pop, but too much in the air we breathe may cause problems
in the future.