Causes of Global warming

When asked to talk about the "causes" of global warming .. I decided to wikipedia as much information as i could and came up with "THREE" main causes

1. Greenhouse gases in the atmosphere
2. Feedbacks ( i know i know .. that doesn't sound like a "cause" .. but it is ! .. i'll get back to it in a few .. )
3. Solar variation

now .. I'm supposed to just talk about ONE cause .. but i'm guessing .. the more you know .. the more 'interested' you'll be when it comes to global warming .. PLUS ... you'll know what NOT to do if ever you wanted to be part of the "stop the global warming" group (or atleast i think that's what they call them selves !!)

now .. back to business

Greenhouse gases in the atmosphere

The greenhouse effect was
discovered by Joseph Fourier in 1824
and was first investigated quantitatively by Svante Arrhenius in
1896. It is the process by which absorption and emission of infrared
radiation by atmospheric
gases warms a planet's
atmosphere and
surface.
Greenhouse gases create a natural greenhouse
effect, without which,
mean temperatures on Earth would be an estimated
30 °C (54 °F) lower,
so that Earth would be uninhabitable.[10]
Thus
scientists do not "believe in" or "oppose" the greenhouse effect as
such;
rather, the debate concerns the net effect of the addition of
greenhouse gases,
while allowing for associated positive and negative feedback
mechanisms.
On Earth, the major natural greenhouse gases are water
vapor, which causes about 36–70% of the greenhouse effect (not
including clouds); carbon dioxide (CO2),
which causes 9–26%; methane (CH4), which causes
4–9%; and ozone,
which causes 3–7%. The atmospheric
concentrations of CO2 and CH4 have increased by 31% and 149% respe.....

ok .. I guess if i was to post the "scientific" meaning of each cause you'll end up clicking the [x] box before you even finished the first paragraph ...

so let me try and summon it all up in a few lines ..

greenhouses are those houses made out of glass that farmers use to grow plants that require a lot of hear at as much sun-rays as they can get ! .. hence the glass .. to stop the sun-rays from leaving the 'house' .. and that's exactly what's happening now-a-days .. we've used to much harmfull gases .. from CO2 to carbon dioxide (for some reason .. i have a feeling those two are the same .. glad i didn't go to a normal high-school or i'd of flunked)

those gases go up into the atmosphere ... and hang around ... well .. not hang around HANG AROUNG like teens do in the malls .. but just 'linger' in the air .. and the more gases we use .. the thicker the layer of 'harmfull gases' start building up .. and the more the build up .. the less sun-rays exit our atmosphere ..

so in other words .. its stuck .. it enters our atmosphere .. and when it wants to leave .. it can't ! ..

I guess that explains what "the greenhouse effect" means !

-------------

now ... the "FEEDBACK"

since i'm not 'obligated' to going into details about the other causes .. i figured i'd just post what information i've found on the 'feedback' effect .. its quite interesting to read

The effects of forcing agents on the climate are complicated by various feedback
processes.
One of the most pronounced feedback effects relates to the
evaporation of water. CO2 injected into the atmosphere causes a warming of the
atmosphere and the earth's surface. The warming causes more water to be
evaporated into the atmosphere. Since water vapor itself acts as a greenhouse
gas, this causes still more warming; the warming causes more water vapor to be
evaporated, and so forth until a new dynamic equilibrium concentration of
water vapor is reached at a slight increase in humidity and with a much larger
greenhouse effect than that due to CO2 alone.[17] This
feedback effect can only be reversed slowly as CO2 has a long average atmospheric lifetime. Feedback effects due to clouds are an area of ongoing
research
and debate. Seen from below, clouds absorb infrared radiation and so exert a
warming effect. Seen from above, the same clouds reflect sunlight and so exert a
cooling effect. Increased global water vapor concentration may or may not
cause an increase in global average cloud cover. The net effect of clouds thus
has not been well modeled, however, cloud feedback is second only to water vapor
feedback and is positive in all the models that contributed to the IPCC Fourth
Assessment Report.[17]Another
important feedback process is ice-albedo feedback.[18] The
increased CO2 in the atmosphere warms the Earth's surface and leads to melting
of ice near the poles. As the ice melts, land or open water takes its place.
Both land and open water are on average less reflective than ice, and thus
absorb more solar radiation. This causes more warming, which in turn causes more
melting, and this cycle continues.Positive feedback due to release of CO2 and
CH4 from thawing permafrost is an additional mechanism contributing to warming.
Possible positive feedback due to CH4 release from melting seabed ices is a
further mechanism to be considered.

The Solar variation

Variations in solar output, possibly
amplified by cloud feedbacks, may have contributed to recent warming.[19] A
difference between this mechanism and greenhouse warming is that an increase in
solar activity should produce a warming of the stratosphere while
greenhouse warming should produce a cooling of the stratosphere. Stratospheric
warming has not been observed.[20]
Other
phenomena such as solar variation combined
with volcanoes
have probably had a warming effect from pre-industrial times to 1950, but a
cooling effect since 1950.[1] However,
some research has suggested that the Sun's contribution may have been
underestimated. Researchers at Duke University have
estimated that the Sun may have minimally contributed about 10–30% of the global
surface temperature warming over the period 1980–2002.[21] Similarly,
Stott et al. estimate in 2003 that climate models overestimate the relative
effect of greenhouse gases compared to solar forcing but also that the cooling
effect of volcanic dust and sulfate aerosols has been underestimated.[22] They
conclude that even with an enhanced climate sensitivity to solar forcing, most
of the warming during the latest decades is attributable to the increases in
greenhouse gases.

more at wikipedia.org

that about summons it all ..

cheerio !