Background on the Global
Warming Debate
As you
may or may not know one of the more controversial topics in the world today is
global warming.
- Some people believe that global
warming is a serious threat to our society, economically,
socially, politically, and action must be taken immediately to try to
alleviate it's effects.
- Others believe global
warming to be a myth and any actions taken in response to global
warming will be harmful to the economy and therefore society as a whole.
- These are the extreme viewpoints.
There are many who believe somewhere in the middle when
it comes to global warming issues (such as, it's happening, but it
is not a threat, or it can lead to minor problems, so let's
find a way to adjust), and equally many who simply do not have an
opinion.
This
week, part one of the Global Warming Debate, we will present the
facts about global warming, the basic arguments presented by both sides, and
the political climate with regards to global warming. You will be responsible
for interpreting various viewpoints on an issue, and formulating your own
opinion based on the facts, and the quality of the reasoning. It is perfectly
possible for two people to look at the same facts, and hear the same arguments,
and come to different conclusions about what needs to be done.
The
problem is that the global average temperature has been rising
in recent decades. NASA-Goddard Institute for Space Studies has a
page showing these changes of the global average temperature,
as well as changes locations and in different seasons. The 2000 year temperature trend also shows the
warmer temperatures this century. Many people believe this temperature change
is associate with increases in carbon dioxide. This is because of the greenhouse effect.
Some
have criticized the validity of the data showing an increase in global mean
temperature because satellite data has shown the opposite trend. However, this
opposite trend is focused mainly on the temperatures in the upper atmosphere,
whereas the surface temperature trends shown above are only for the surface.
The
next questions involve the actual relationship betweengreenhouse gases and
temperature increases, as well as whether or not us humans are actually
causing the greenhouse gases to increase.
Some believe that climates will change significantly as a result of global warming. Look at a few examples in the Midwest, according to this link, Wisconsin summers in 2095 will be the equivalent of Arkansas summer now. This could lead to adverse conditions for certain species of plants and animals, disrupting the food supply, or in other cases, increase the length of the growing season, adding to the food supply. Many also believe that global warming will lead to more disease being spread from the tropics, sea level rise as a result of melting polar ice caps, more hurricanes, and fires. See early warning signs.
Some believe that climates will change significantly as a result of global warming. Look at a few examples in the Midwest, according to this link, Wisconsin summers in 2095 will be the equivalent of Arkansas summer now. This could lead to adverse conditions for certain species of plants and animals, disrupting the food supply, or in other cases, increase the length of the growing season, adding to the food supply. Many also believe that global warming will lead to more disease being spread from the tropics, sea level rise as a result of melting polar ice caps, more hurricanes, and fires. See early warning signs.
There
are many theories on Global Warming, some of which involve the ideas of
feedback loops.
- A positive feedback loop is one
that amplifies changes.
An example of this the world's population. With a fixed birth
rate, the population of the globe will continue to grow (until checked). Large
populations cause large numbers of births and large numbers of births result in
larger population. The change gets amplified each step. These feedback loops
are dangerous.
- A negative feedback loop is one
that tend to mitigate a change.
An example of this is homeostasis, the maintenance of body
temperature. As a person's body gets too hot, (s)he begins to sweat in an
attempt to lower the temperature. If their body is too cool,(s)he will begin to
shiver in an attempt to increase the temperature.
Global
warming is likely to be amplified by a few key positive feedback loops...
- Ice and Snow As the earth warms, the
levels of ice and snow decrease, this decreases the surface albedo,
allowing for an increase in absorbed solar radiation at Earth's surface.
This leads to more warming and less ice and snow cover.
- Water Vapor As the earth warms, so does
the atmosphere, this increases the amount of water vapor the atmosphere
can hold. Warmer temperatures mean more evaporation, leading to a higher
amount of water vapor, the most powerful greenhouse gas in existence, and
consequentially even higher temperatures.
Three effects are poorly understood...
- Changes in cloud cover could
dampen the effects, especially if they are low clouds. Most climate models
forecast that this will be the phenomenon that eventually brings the earth
back to equilibrium.
- Aerosols may or may not counteract
global warming. Some studies have shown aerosols to block out a
significant amount of incoming solar radiation, others have not.
- The ocean circulation may change
leading to varying effects in different parts of the world. Although
"The Day After Tomorrow" is not a plausible scenario, many
scientists believe that although the earth will warm as a whole, some
regions, especially western Europe, may cool as a result of weaker ocean
circulation.
These
effects make global warming scenarios very different.
The
debate mainly pits environmentalists against economists.
- A majority of environmentalists
and scientists believe global warming is occurring and is an issue that
needs to be dealt with. Environmentalists say that other species, even the
dinosaurs, could have died off in the past as a result of climate change,
and we could suffer the same fate.
- A majority of economists and
businesspeople, more concerned with the economy, do not see global warming
as an issue. Economists often point to previous claims by scientists that
turned out to be untrue or contradictory to the current consensus.
Points made by Supporters
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Points made by Opponents
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