Certain gases in the atmosphere, known as greenhouse gases, trap heat and regulate the planet's climate like a warm blanket. Greenhouse gases including water vapor, carbon dioxide and methane make up about 1% of the atmosphere and absorb some of the sunlight that reaches the Earth's surface, preventing about 30°C of heat from escaping back into space. This greenhouse effect is essential to maintaining a livable temperature on Earth and allowing life to exist.

1. Aenean a magna vel pede vestibulum
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[Date]
ALIQUAM
THE GREENHOUSE EFFECT
http://environment.about.com/od/globalwarming/a/greenhouse.htm
http://cikgubiology.blogspot.com/2009_11_01_archive.html
Life on Earth
depends on the
Sun’s energy.
About 30% of the
sunlight is
deflected and
scattered back
into space. The
rest reaches the
planet's surface
and is again
reflected upward
or is absorbed by
the surface. This
is the function of
the "greenhouse
gases.”
We couldn’t live
without it!
Greenhouse gases (water
vapor, CO2, methane: ~1% of
the atmosphere) regulate our
climate by trapping heat and
acts like a warm-air blanket
that surrounds the planet.
Without it, scientists estimate
that the average temperature
on Earth would be colder by
approximately 30 o
C, far too
cold to sustain our current
ecosystem.