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Possible Culprits
The amount of heat energy reaching Earth from the sun can be affected in two ways. One way
would be if the sun’s output were to change and the other would be if Earth’s
position relative to the sun were to change. These changes can be illustrated by
visualizing a campfire. As the campfire dies, its output changes, decreasing the energy
available to warm the campers. If more logs are added to the fire, the changes in output
would increase the energy and the temperature. Now suppose that the campfire is really a
propane heater that maintains a constant temperature. Although the temperature remains
constant, the camper who forgot to bring a coat has to move closer to the flame in order
to get warm. Another clue in the
search for culprits responsible for Earth’s rising temperatures may be greenhouse
gases. Greenhouse gases provide insulation that traps some of the sun’s heat energy.
As the concentration of greenhouse gases increases, the insulation becomes thicker and
more of the energy is trapped, resulting in an increase in temperature. This is similar to
putting on a heavier coat to get warmer. |
