Download Green chemistry: webquest

Ben Lapworth
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The increase in average temperature of the
earths surface caused by an enhanced
greenhouse effect due to increased
concentration of greenhouse gasses in the
atmosphere.
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Well, its quite simple really. It all starts at the
sun. due to the sun’s immense ferocity of
heat it emits huge masses of energy in the
ultraviolet, visible light and infrared regions
of electromagnetic radiation.
To try and regain some sort of balance the
earth has to re-emit some of this energy, but
as it’s a fair bit cooler than the sun it only has
enough energy to re-emit infra-red radiation.
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Yeah, finished there, simple really?
Not quite. In the earths atmosphere there is
some gasses (known as greenhouse gasses)
determined to make it more confusing,
annoying and warmer (not to mention
prolonging this homework!).
The 3 main suspects in the stratosphere and
troposphere are; water vapour, methane and
carbon dioxide.
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But what do these 3 gasses have to do with
anything?
Quite a lot actually. They affect the reemission of infra red radiation by preventing
It from leaving our atmosphere.
As the earth emits this radiation trying to get
rid of it, these gasses absorb it thus keeping it
locked in our atmosphere.
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Actually, that’s not a fair comment. Its not
the fault of the atoms within the gas
molecules, but the bonds holding these
atoms together that are to blame!
The c=o bond (carbon dioxide), the o-h bond
(water) and c-h bond (methane) are all to
blame. They can stretch, twist or bend to
receive the energy from the infrared
radiation.
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This is a very large contributing factor in what
we call global warming. If the earth cannot
emit this extra energy, then it remains in our
atmosphere, thus increasing the temperature
(because these molecules will reemit some of
the energy- back to the earths surface!).
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The ‘greenhouse effect’ of a given gas is how
gasses can absorb infrared radiation emitted
from the earths surface and then re-emit
some of this energy back too the earths
surface.
This greenhouse effect is present on water,
carbon dioxide and methane molecules. It
can be increased dependant on atmospheric
concentration and ability to absorb radiation.
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Concentration is basically how much of a
species there is per unit volume.
If there is more ‘stuff’ in less space, there is a
high concentration.
The concentration of greenhouse gasses
affects the emission of infrared radiation
from earth. With more greenhouse gasses
filling up space in the atmosphere, there are
more opportunities for radiation to be
absorbed.
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Due to humans (and some other natural
occurrences) constantly dishing these
greenhouse gasses into the atmosphere,
there are more and more of them filling up
the same amount of space.
This just means that radiation is more likely
to be emitted and re-emitted (back to earth)
increasing global warming one molecule at a
time.
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Carbon dioxide has a relatively small ability to
absorb radiation (infact it has a greenhouse
factor of one) but due to its huge
concentration in the atmosphere it still
contributes to 60% of the greenhouse effect.
Methane has a larger ability to absorb
radiation (factor 30) but is less concentrated
in the atmosphere so contributes to 15-20%
of the greenhouse effect.
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This could end up quite messy. There's a chain
of events leading from the ignition key on
your car, to the polar ice caps melting and the
end of the earth as we know it. Okay, maybe
a little dramatic for now, but whilst its
possible…
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We need to work collectively, as the great
human race, to do something about this
global warming (leading from atmospheric
increases in greenhouse gasses).
Whilst there are many natural excretions of
these harmful gasses into the atmosphere,
there are also many unnecessary ones being
pumped out into the atmosphere by humans.
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We CAN, we MUST, we NEED, to do
something about it.
Limiting the amount of fossil fuels burned by
us, is the most obvious answer. These are the
things that emit shed loads of carbon dioxide
into our atmosphere, where it sits there,
stealing the infrared energy and chucking it
back at us.
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First step is too use this as little as possible.
Why drive a car when you can walk or cycle
(or even lift shares and busses limit the
amount being burned)? Why get a ferry when
you could swim to Australia? Okay, maybe
slightly exaggerated but you get the point.
Stop unnecessarily burning fossil fuels! We
know where you live….
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The key thing to do, however, is to find an
alternative bio source of energy. I don’t mean
a hamster running in a wheel to spin a
turbine, I mean a proper source of energy.
We are grasping the concepts of solar energy,
wind energy, hydroelectric energy and even
geothermal energy. We have an
understanding of how these make energy,
but now we need to make them more
efficient.
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This is a way of collecting potentially harmful
carbon dioxide, piping it underground and
storing it between rock formations below the
earths surface. The carbon dioxide could
react with substances under the surface to
make carbonates, this would make them
easier to store below the earths surface as
solids aren't as likely to escape as gasses.
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The Kyoto protocol was made so nations
could agree to fight global warming.
Countries agreed to limit there emissions of
greenhouse gasses.
It’s a start, but major nations such as
America, Australia, china and India refused to
sign it.