Originally posted by blackpanther1967
In layman's terms...
... I think you're very confused. Let me help you out!
Earth's atmosphere, continually in motion, is about 800 km (500 miles) deep which protects it from harmful solar radiation and supports all living
It is made of air which is a mixture of O (21%), N (78%), CO2 (0.037%) and other gases in negligible amounts such as H, the noble gases, and O3. It
also contains water vapor. These gases are densest at the Earth's surface and get less dense with increasing height. Around 90% of the atmosphere by
weight lies in the lowest 15 km (9 miles) above the surface. Statistically, that may not sound very thick, but have you thought about how high 15 km
(9 miles) up really is?
Air pressure is the weight of air resting on a given area of the Earth's surface. Air pressure (also called atmospheric pressure) is greatest at sea
level, where the air is densest. On a mountain peak the air is less dense and the pressure is lower.
Low pressure also occurs when air is warm, expands, gets lighter and rises. High pressure occurs when air gets cold, contracts, becomes heavier
(denser) and sinks (falls). Air flows from regions of high pressure (highs) to low pressure (lows) as it tries to equalize the difference between the
two, known as the pressure gradient. This movement of air is wind. The greater the difference between the high and the low pressure, the greater the
wind speed. The closer the isobars on a weather map are together, the stronger the winds.
Keep in mind that all these temperature changes and movement of air does not affect the thickness of the Earth's atmosphere; it merely affects the
temperature and wind patters within
About 70% of the Earth's surface is sea water and the ocean currents have a major influence on climate and weather. Surface currents are produced by
the prevailing winds and follow the same general directions. They play a major role in transferring heat from the tropics to the polar regions. Land
surfaces are poor conductors of heat; their temperature increases rapidly in sunshine and decreases equally quickly at night. The sea is different
with little change of surface temperature from day to night except where it is exceptionally shallow. Because of this, the sea warms up and cools down
more slowly than the land, creating temperature contrasts at different times of year.
On a larger scale the sea acts as a reservoir of heat from the summer, keeping coastal regions milder in the autumn than regions inland. In summer, it
warms up slowly providing cooling sea breezes keeping temperatures near coasts below those inland. On a global scale, temperature contrasts are
responsible for the effect known as continentality. The inland areas of continents tend to have a much greater temperature variation than coastal
areas, where the influence of the sea produces a much smaller variation.
Also, tornadoes and hurricanes are completely natural, and certainly not induced by 'global warming', if it's even real (the jury's still out on
that one). Their occurences in 2004 are no more or less dramatic than in any other year -- especially statistically speaking. Yes, it's been a busy
hurricane season in the U.S., and the last U.S. hurricane season this busy was in 1886. Was that due to 'global warming' too?
In the words of my good friend, who has a B.S. in Geology, "Mother Earth can shake humanity off like a bad cold." This is not to say that local
environments aren't affected by humanity's presence, but globally speaking, Earth has little to fear from human presence. We are every bit at the
mercy of the Earth's climate -- and our ability to affect it, for good or bad, is indeed negligible in the end.
(adapted from www.about.com...
) Well, that should at least get you started in your studies... good luck!
[edit on 9/29/2004 by ThunderCloud]