Headings Environmental
Issues Search Questions 
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Environmental Issues.
2) Fossil fuels are burnt on a huge scale - Greenhouse Gases.
How does carbon dioxide cause global warming?
The temperature of our
planet is a balance
between
the amount of heat it receives in
the day from the Sun
and the amount of heat given out at
night into space.
In the day, energy from the
sun reaches the Earth in the form of
electromagnetic
radiation (this includes heat and light).
The surface temperature (and the atmospheric temperature) of the Earth
rises in
the day. At night, heat energy from the Earth is lost to
space.
This heat energy is a fairly narrow
range of electromagnetic radiation
called infra-red
radiation.
Carbon
dioxide, methane, water vapour and nitrous oxides
absorb infra-red radiation
in the same range which is
given off by the Earth at night.
More carbon dioxide in the
atmosphere means more heat is absorbed,
and less can escape at night into
space.
The overall effect is that the
Earth receives more heat in
the day
than it can lose at night, so the temperature rises.
The same
thing happens in a greenhouse
where glass instead of
carbon dioxide is used to prevent the heat
escaping at night.
So, carbon dioxide, methane, water vapour
and nitrous oxides
have been
called greenhouse gases.
Headings Environmental
Issues Search Questions
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