Page 12 - Curriculum Visions Dynamic Book

Carbon dioxide in the environment
Carbon dioxide gas (like water vapour) strongly absorbs, or soaks up, the heat that is radiated by the Earth out into space. Without carbon dioxide and water vapour, the Earth would be
a very cold, almost uninhabitable place, some 25°C colder than it is today.
The amount of heat stored changes with the amount of carbon dioxide gas in the air. Over the last few centuries, people have increasingly burned more fuel, so much
more carbon dioxide has been added to the air than was previously the case.
The extra carbon dioxide has been able to absorb even more of the earth’s heat, leading to a gradual warming of the air. This process, known as the Greenhouse Effect, has been charted for more than a century.
Some scientists are concerned about the build up of carbon dioxide because they fear that “global warming” will cause all sorts of unpredictable changes, such as droughts and floods, as well as a possibly disastrous rise
in the sea level as the warm air causes the Antarctic ice sheet to melt.
 The passage of long wave radiation from the earth and back to space
is slowed by the increasing “blanket” of carbon dioxide in the atmosphere as more of the gas is released by burning fossil fuels.
 Plants need carbon to make the cells of their bodies. They extract carbon from carbon dioxide gas using the energy in sunlight.
Also...
The Earth absorbs energy through solar radiation. This
is mostly short wave radiation. The gases in the atmosphere are largely transparent to solar radiation. The incoming solar radiation does little to warm the air, therefore, and mainly warms the land and oceans.
The wavelength of radiation depends on the temperature of the radiating body. The Sun is very hot and so radiates in short wavelengths. However, the Earth is cool and radiates in longer (infra-red) wavelengths.
Water vapour and carbon dioxide gas both absorb in the infra-red wavelengths better than in short wavelengths, so they absorb some of the heat energy that would otherwise be lost to space. This is what makes the atmosphere warmer and causes the Greenhouse Effect.
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