KEEPING THE PLANET GREEN: THE GREEN HOUSE EFFECT

Space is not a friendly place. It’s big, mostly empty of large masses, and really, really cold. Not the conditions you’d logically pick for a thriving planet teeming with life. Yet here we are, billions of life forms all living together on a little ball of dirt. In all the Solar System, with its variety of planet types and sizes, only Earth has developed an atmosphere that allows the continual mechanism of life to flourish. A process known as the green house effect protects that atmosphere.





How It Works, or, "Raise The Shields, Scotty!"
Joseph Fourier discovered the green house effect in 1824, and it is the process of the literal absorption of infrared radiation by an atmosphere and how it warms the planet. It is the rise in temperatures that the Earth experiences due to certain gases in the atmosphere such as water vapor, carbon dioxide, nitrous oxide, and methane, for example. These gases trap energy from the sun, and without these sorts of gases, all the heat would escape back into space and the average temperature of Earth would be about 60F degrees cooler.

The term green house effect can be used to refer to several things, such as the natural green house effect, that which is due to the naturally occurring green house gases, as well as the enhanced green house effect, that which results from gases that are emitted as a result of human activities.







The Earth receives an enormous amount of solar radiation, and the solar power from this, which is hitting the Earth, is then balanced over time by an equal amount of power radiating from it. Because the atmosphere, which is protecting the Earth, is such a good absorber of long wave infrared, there is basically a one-way blanket that is formed over the Earth's surface.

The result of the green house effect then, is due to the fact that average surface temperatures are considerably higher than they would be if the surface temperature of the Earth were determined solely by albedo and blackbody properties of the surface.

The actual degree of this effect in itself is primarily dependant on the given concentration of greenhouse gases in the planetary atmosphere. The actual key to the green house effect is that the atmosphere is relatively transparent to any solar radiation, and yet is strongly absorbing in the infrared. While most of the solar radiation hits the surface of our planet Earth, most of the infrared escaping to space has already been emitted from the atmosphere, and not from the surface.

The actual degree of the green house effect is dependant on the concentration of green house gases that are in the planetary atmosphere. For instance, the deep and carbon dioxide-rich atmosphere of Venus causes surface temperatures which are hot enough to melt lead and the thin atmosphere of Mars causes a particularly minimal green house effect, whereas the atmosphere of the Earth allows for much more habitable temperatures.