by reader CoRev
The Greenhouse Effect. How it Works
From Anthony Watts site, we have this graphic describing the heat wave length absorbtion properties of the Green House Gases (GHG).
Water vapor is a far more pervasive and heat absorbant (see the above chart) GHG than any of the other GHGs. That does not imply it is the most effective GHG supporting the green house effect.
The workings of GHGs are very complex and still not fully understood. What is known is that:
1. GHGs maintain the planets current temperature range.
2. GHGs make up only 1% of the Atmosphere. Earth’s atmosphere is primarily composed of nitrogen (78 percent) and oxygen (21 percent), which do not react well to infrared wavelengths.
3. The overall atmospheric make up of GHGs is: Water Vapor 0 – 4% (Varies by temperature and pressure), CO2 .035%, Methane .0002% and Ozone .000004%.
4. The Sun emits energy in all ranges of electromagnetic frequencies (EM, EMF), from sound to cosmic rays, including the ultraviolet, visible, and infrared spectrum from .2 to 70 μm.
5. GHG molecules intercept these waves in both directions as they enter the atmosphere and as they are reflected by the Planet. 70% reach the surface of the Earth and heat it; therefore, those waves intercepted as they enter the atmosphere help cool the planet’s surface.
6. In intercepting these waves they are heated. Heated molecules also immediately release some of this heat IN ALL DIRECTIONS. Some heat energy is thereby blocked; some transmitted back to space; some transmitted down to the planet, and some to adjoining molecules.
7. The Earth releases some of its heat, and can be seen in the long wave infrared spectrum. Some of this surface heat energy is intercpeted by the GHGs, some bypass them and escape back to space, some of the intercepted heat energy is sent back down to the surface.
8. The heat sent back to the planet by the GHG is the “greenhouse effect”, keeping our atmosphere a calculated ~30 centigrade warmer than it would be otherwise.
If you are having trouble visualizing this, try this:
Imagine a basketball gym 1% covered by those children’s windmills (GHG molecules) all spinning and various distances from the floor to the ceiling. In the gym is a huge set of fans (space) that suck much of the air out of the gym. Now turn on the fire extinguishing water system (the Sun). Some of those water droplets are intercepted by the spinning blades. Most are not intercepted and bounce off the floor. The spinning blades are hit from all directions. All the droplets that hit the spinning blades are thrown off in all directions. The tops of the blades are wet, the bottoms, the edges and the floor are all wet. And, a large part of the droplets are ejected by the fan. Turn off the water (night) and keep the fan running, and we see that some of the water is ejected via the fans and some is returned to the floor by the spinning blades of the windmills. The most effective at this are those windmills close to the floor. Repeat (days/months). Extend the length of time between on/off cycles of the water (seasons) and repeat.
That’s a very simple description of how the Green House process works. To expand upon it and add some minor complexity we can change the colors and quantity of windmills to reflect a specific ratio for each gas making up GHGs. Each windmill would vary in size shape and speed to reflect the various green house properties of the GHGs.
You should have many questions. For instance what happened to all those water droplets/energy waves that didn’t make it to space? How many of the droplets were effected, how, and what was their states? How were the windmills/GHG molecules effected? What was the direct and indirect effects on the molecules? As we delve deeper into the subject we find even more intricacies. We’ve just scratched the surface of the complexities still unknown about the Green House process.
This only touches on the complexities of the greenhouse effect. And this is only one part of the whole; water is also the major part of the hydrosphere. And now you have a concept for how difficult it is to analyze even this relatively small but important part of the Planet’s climate.