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In the atmosphere, gases such as H2O,
CO2, CH4, CFC, etc., are capable
of absorbing the terrestrial radiation (peaking at infrared wavelength) and
re-radiate in all directions. Thus part of the re- radiation is sent back to
the surface. This means that in the presence of these gases, the atmosphere
will be warmer than without them. These gases thus play the role of glass
panels in a greenhouse. Hence the name greenhouse gases. It is therefore
reasonable to expect that increasing concentrations of greenhouse gases will
cause warming in the atmosphere.
Currently, CO2 is the main suspect of causing global
warming because combustion of fossil fuel naturally injects CO2
into the atmosphere. Whereas other natural processes also inject CO2,
the industrial combustion process seems to play a significant role in the
concentration increase. |