Our Changing Planet: Global Warming and You
By Kevin Williams
Earth’s average
temperature has changed numerous times in the history of our planet. Today we
are in the midst of a warming trend in the average annual temperature that is
threatening life, as we know it, on our planet. Global surface temperatures
have increased an average of 0.6 to 1.2 degrees Farenheight since the late
nineteenth century. The last fifteen years has contained the ten warmest years
of the twentieth century. 1998 was the warmest year ever recorded by human
beings. It is an undeniable fact that the Earth is warming in temperature (see
figure1). There is considerable debate over the cause of this warming trend, is
it natural or caused by humans? Whatever the cause, Global Warming is a serious
issue that confronts mankind today, and must be addressed by all of humanity.
Figure 1
Why is the earth warming?
There are several reasons why the
Earth is warming, some of them are natural, and some are not. The largest
natural factor in global warming is the changing patterns of Earth’s
relationship to the Sun. There are three major types of changes that the Earth
undergoes that influence global climate. First, the Earth’s orbit around the
Sun is not a perfect circle; instead, the Earth circles the Sun in an
elliptical orbit. This orbit changes shape on a 100,000-year cycle, and the
shape of the orbit determines how close the Earth is to the Sun. When the orbit
is more circular the Earth is closer to the Sun for longer periods of time, and
when the orbit is elliptical, the Earth is further away from the Sun. The
ellipticity of the Earth’s orbit on its own would not make a large difference
in global climate, but when combined with the other two patterns of change it
helps to make a large difference in global climate. (see figure 2.1)
The second type of change that the
Earth undergoes is in the tilt of its axis, which in turn changes the angle at
which solar rays strike the Earth. The axis of the Earth is tilted at an angle
to the Sun, which varies according to a 44,000-year cycle. The angle at which
it is tilted ranges from 21.5 degrees to 23.5 degrees. When the Earth’s axis is
tilted at a greater angle, solar radiation strikes the Earth at a larger angle,
therefore reducing the amount of energy that reaches the Earth. (see figure
2.2)
The last change that the Earth goes
through is the change in direction that the Earth’s axis points. Currently the
Earth’s axis points toward the North Star. The way that the axis changes
direction can be visualized if you think of a clock. Currently the Earth’s axis
points toward eleven o’clock, but in 21,000 years, the Earth’s axis will point
toward one o’clock. This change in direction determines which hemisphere points
toward the Sun. This in turn determines which hemisphere will be the warmest,
and also determines the length and intensity of the seasons. When the Northern
Hemisphere is pointed away from the Sun, the winters will be longer and colder,
helping to create glaciers and ice caps and in turn cool global
temperatures.(see figure 2.3)
The Earth is currently in a position
that is creating warmer temperatures around the entire world. This period is
referred to as an interglacial event, and is a recurring pattern in the Earth’s
history. What makes this period different from all others is the existence of
human beings on the planet. There are many facets of human activity that are
helping to accelerate the warming of the Earth. The first and potentially most
dangerous human activity is the introduction of more carbon dioxide into the
atmosphere. (see figure 3) Many things we do create carbon dioxide pollution,
including but not limited to, the burning of fossil fuels by cars, machinery,
and power plants. Another source of carbon dioxide is the manufacturing of
products such as furniture, cars, computers, and many other domestic and
commercial products. 
Figure 3
Atmospheric CO2 concentrations in parts per million, Mauna Loa, Hawaii. Source: C.D. Keeling & T.P. Whorf, Scripps Institute of Oceanography. Data available from the Carbon Dioxide Information Analysis Center (CDIAC).
Another reason for increase in
carbon dioxide is the reduction of carbon dioxide sinks around the globe.
Carbon dioxide sinks are things that absorb carbon dioxide. Examples of carbon
dioxide sinks are forests and marine plants and photosynthesizers. In the past
several decades we have decimated the world’s forests and polluted our
waterways to the point of destroying large amounts of carbon dioxide absorbers.
Why is the increase in carbon
dioxide levels so important to increasing global temperatures? The reason is
carbon dioxide is the largest contributor to what we call Greenhouse Gasses.
The Greenhouse Effect is the reason why Earth maintains comfortable
temperatures for human life. Earth’s atmosphere acts like a greenhouse by
trapping solar energy from both the Sun and from the reflection and radiation
of heat by the Earth’s surface. Figure 4 explains the process by which the
atmosphere helps warm the Earth. The problem of increasing Greenhouse Gasses is
the intensification of the Greenhouse Effect, therefore increasing the amount
of radiation trapped by Earth’s atmosphere.
Figure 4
What are the
Consequences of Global Warming?
There are many consequences of
global warming that are potentially devastating to both Human life and natural
life. The first major consequence is the potential for large increases in sea
level. There are two reasons why sea level is rising. The first is due to basic
chemical properties of water. Like any fluid, water will increase in volume
when it is heated. The warming of global temperatures has the effect of warming
the average temperature of the world’s oceans and therefore increasing their
volume and raising sea level. This process is known as eustatic sea level rise.
The other reason for sea level rise
also relates to global warming. With the increasing global temperatures, there
is an increase in the melting rates of polar ice caps and other glacial
features around the world. When these glaciers melt they release more water
into the oceans creating a rise in sea level. With both eustatic sea level rise
and the melting of ice in polar caps and glaciers there is a potential for sea
level to rise in large amounts over the next several decades. Many scientists
are predicting a sea level rise of five to six meters by the year 2070 if the
Earth continues to warm at present rates. However if the rate of global warming
increases we could see sea level rises of 20 meters or more. This rise in sea
level will have tremendous consequences for coastal communities and ecosystems
along the coast. If sea level were to rise ten meters then many parts of North
America’s East Coast, Italy’s North East Coast, many parts of Bangledesh, and
much of the Netherlands will be under water. Of course, the more sea level
rises the more land will be under water around the world.
Another frightening consequence of
global warming deals with climate changes across the world. When the Earth
warms up, plants and animals respond in many ways, some move to new areas where
the climate is hospitable to them, others try and move but are unable to find a
suitable climate and they become extinct. Africanized honeybee’s in the United
States are a good example of this phenomenon. In the last decade these bees
have spread from Mexico into the United States as far north as northern Texas
and points across the United States such as areas from Georgia to California.
These bees are able to move north because of increasing temperatures that give
them a larger area in which they can live. An example of an animal that is
unable to adjust is the Polar Bear. The last decade has seen a large decrease
in the population of Polar Bears in the artic circle. This decrease is due to
the shrinking of the Polar Bears habitat due to the warming of the Earth.
The most worrisome effect of global
warming for people is the changes that it will entail for agriculture. Some
places that have traditionally grown certain kinds of crops will be faced with
the inability to grow these crops and perhaps the inability to grow any crops
at all. Some areas that are currently very productive for agriculture will be
faced with drought or excessive rainfall and will have to change methods of
growing food. There are current hypothesis's that show many parts of the United
States as deserts due to the increase in global temperatures and the changing
weather patterns. These studies also show places like Canada and Siberia
becoming much more compatible to agriculture.
What Can We Do to Stop Human Accelerated Global
Warming?
Left alone, the Earth will adapt to
the changing climate patterns and sea level rise, but if humans accelerate this
process the Earth will not be able to keep up with global warming. With human
accelerated global warming we will see the catastrophic changes in climate and
sea level predicted in the preceding sections. Is there anything we can do,
short of the total stopping of human life as we know it, in order to stop human
accelerated global warming? There are many things that we can do on the
individual, national, and global levels to help reduce and possibly eliminate
the human influence on global warming.
A large percentage of Greenhouse
Gasses comes from individuals using their cars and lawn equipment, and
individuals also support the use of many products that cause pollution in their
manufacture.(See Figure 5) As an individual there are many ways you can help to
help reduce the amount of pollution that you create. The first and most
effective way to reduce the amount of Greenhouse Gasses you produce is to
reduce the amount of time spent behind the wheel of your car. You can do this
by walking on shorter trips, and riding mass transportation whenever possible.
In the near future there will be affordable and practical electric or very low
emission automobiles. You can also use electric lawn mowers and lawn equipment
wherever they are available. Another way that is less practical is to avoid the
use of products that are manufactured in ways that cause pollution. Products
like these include plastics and other synthetic materials that are created by
using high heat that requires burning of fossil fuels, thus releasing carbon
dioxide. The problem with all these measures comes with personal preference.
People like their cars and their lawn mowers and their plastic lawn furniture.
The only way that an individual will help curb carbon dioxide pollution is to
make personal sacrifices, something that many people are unwilling to do.
On the national level there are many
effective measures that can be employed to help the growing problem of global
warming. The first major concern of nations should be to find ways to produce
clean electricity. Burning fossil fuels to produce power produces large amounts
of air pollution of all kinds, especially carbon dioxide. The second concern of
nations should be to produce effective and efficient systems of mass
transportation for their citizens. These systems of mass transportation would
save tons of carbon dioxide from entering the atmosphere and contributing to
global warming. The last major step nations can do, and the most effective, is
to regulate the emissions that come from factory smokestacks. (See Figure 5)
Governments can do this by necessitating factories to use carbon dioxide
scrubbers that reduce the amount of carbon dioxide coming out of the
smokestacks. There are problems with these measures that will prevent
governments from enacting them. The problem is that these programs are
expensive to enact and monitor. As long as governments need to watch their
spending, programs such as these will not have a future
. The last and possibly most effective
way that Human accelerated global warming can be slowed or stopped is found at
the global level. The creation of a super-national control board with the
purpose of limiting the production of greenhouse gasses and promoting
development of carbon dioxide sinks would be the best way to curb global
warming problems. This control board would have to be independent of all states
and have a way of enforcing its rules and decisions. One way of creating this
board would be
Figure 5
to have five
permanent member countries such as the United States, Britain, China, Russia,
and France, and five other member countries that cycle through all countries
every five years. This control board would have to be enabled to invoke
penalties such as trade restrictions on countries violating policy on
Greenhouse Gasses and destruction of carbon dioxide sinks. The only problem with
this board is that all countries value their sovereignty over the protection of
the environment.
It is
easy to see that global warming is happening and is being accelerated by Human
activity. The question is what we are going to do about it? There are many
possible solutions on all levels, but there are other factors that will prevent
them from being carried out. Until we as a species put our foremost emphasis on
protecting the environment and our planet, we will continue to destroy them.
Think about what our planet means to you and consider whether it is more
important to have a stable environment or to have creature comforts at its
expenses.
Bibliography
http://www.epa.gov/globalwarming/climate/index.html
http://www.ngdc.noaa.gov/paleo/globalwarming/home.html
http://www.enviroweb.org/edf/
http://www.newscientist.com/nsplus/insight/global/global.html
http://www.globalwarming.net/
Schnieder, David.
The Rising Seas. Scientific American Presents: The Oceans, pg 28-30
Greenhouse Effect
and Global Warming, author unknown (handout for geol 3450 at University of
Georgia)
Figures
Figures 1,3,5
obtained from http://www.epa.gov/globalwarming/climate/index.html