Green House Gases

1) Scientists have found that "over the past 250 years humans have been

artificially raising the concentration of greenhouse gases in the

atmosphere. Our factories, power plants, and cars burn coal and

gasoline and

spit out a seemingly endless stream of carbon dioxide. We produce

millions

of pounds of methane by allowing our trash to decompose in landfills

and by

breeding large herds of methane-belching cattle. Nitrogen-based

fertilizers, which we use on nearly all our crops, release unnatural

amounts

of nitrogen oxide into the atmosphere." [6] Natural forces also play a

role

in modeling. Factors such as clouds, plants, and ozone layers are used

in

some models. Society plays a role in models as well, as some

researchers

take into consideration land use changes, population increases, etc.

2) Disagreements on the exact role each element plays in a model

depends on

the individual model and its components. Information from NASA's

website

suggests that factors such as greenhouse gasses, the tropospheric ozone

layer, and solar variability are generating an increase in the Earth's

temperature. However, the same study suggests that fossil fuels,

biomass

burnings and even an indirect effect of tropospheric aerosols are

causing a

general decrease in temperature. [6]

3) Roughly over the last 150 years, the concentration of Carbon Dioxide

has

increased by thirty percent. This boost causes 1.46 Watts per meter

squared

of the sun's energy to be trapped. [6]

4) The concentration of methane has increased from .791 pp/m in 1850 to

1.735 pp/m in 2000 [7]. This contributes to an increase of .48 Watts

per

meter squared of the energy stored [6]. Increases life times of other

greenhouse gasses and increases water vapor in the air. [7]

5) Scientists are gathering more data from the atmosphere and

performing

more experiments with the green house gasses. [7]

6) As problems with models occur, we find ourselves facing two possible

consequences: overreaction and a lack of response. Overreaction is a

possibility, as errors predicting the future might lead us to believe a

situation is much worse than it actually is. This could cause society

to

invest in an extremely costly solution to a problem that truly doesnot

deserve the attention. On the other hand, a model could seriously

underestimate the severity of an issue, causing a lack of reaction, and

in

turn, a horrendous outcome in the future.

7) "A comparative analysis of long-term (several-hundred-year)

temperature

and carbon dioxide (CO/sub 2/) trends suggests that the global warming

of

the past century is not due to the widely accepted CO/sub 2/ greenhouse

effect but rather to the natural recovery of the Earth from the global

chill

of the Little Ice Age, which was both initiated and ended by some

unrelated

phenomenon, the latter expression of which is the very warming

generally

attributed to the CO/sub 2/ increase of the past century."[3] The

natural

recovery from a mini ice age, according to this source, might result in

global warming.

According to another source that used a model to represent the climate

system response to solar and volcanic forcings, "using a

middle-of-the-road

model sensitivity of 3 degC for doubled CO/sub 2/, solar forcings of

less

than 0.5% are too small to account for the cooling of the Little Ice

Age."[4] These volcanic events seem to have had some cooling effect,

but

this model suggests that this event alone was not enough to produce the

Little Ice Age.

8) In order to answer the question, "What would be the consequences of

a

mini ice age?" one may consult the consequences of an ice age that

previously occurred. According to A.T. Grove of the Department of

Geography

at Cambridge University, "Alpine glacier advances

...