Moonbats – if your belief in dangerous man-made global warming is because someone told you carbon dioxide traps heat, therefore, the more carbon dioxide the more heat, then stop reading now. Individuals interested in the true science may want to read Harvard Physicist Lubos Motl explain how physics demonstrates there is no reason to worry about CO2 superheating the atmosphere.
Saturated confusion: The greenhouse effect is the absorption of thermal, infrared electromagnetic radiation emitted from the surface of Earth by the gases in the troposphere - between the surface and a dozen of kilometers above it. These photons would otherwise escape to outer space and leave the Earth cooler than it is because of their existence.
The absorption only occurs if these relatively low-energy transitions are found in the spectrum of a given molecule: recall that the wavelength of ordinary atomic spectra is typically much shorter and the photons carry much higher energies, corresponding to higher temperatures. The requirement that low-energy transitions must be allowed within the molecule is why the mono-atomic inert gases such as argon or even di-atomic molecules such as nitrogen are not greenhouse gases.
In terms of numbers, we have already completed 40% of the task to double the CO2 concentration from 0.028% to 0.056% in the atmosphere. However, these 40% of the task have already realized about 2/3 of the warming effect attributable to the CO2 doubling. So regardless of the sign and magnitude of the feedback effects, you can see that physics predicts that the greenhouse warming between 2007 and 2100 is predicted to be one half (1/3 over 2/3) of the warming that we have seen between the beginning of industrialization and this year. For example, if the greenhouse warming has been 0.6 Celsius degrees, we will see 0.3 Celsius degrees of extra warming before the carbon dioxide concentration doubles around 2100.
If two or more molecules absorb the same wavelength, they all compete for that frequency. As any given wavelength approaches complete atmospheric absorption, adding more molecules produce incrementally smaller effects. In other words, there is a limit to how much heat can be momentarily retained and it depends on how much heat is supplied.
I have used the analogy: Once you mop up the energy the sun spills on the planet each day, having extra paper towels around doesn’t do anything. Lubos uses this analogy: "It's just like when you want your bedroom to be white. You paint it once, twice, thrice. But when you're painting it for the sixteenth time, you may start to realize that the improvement after the sixteenth round is no longer that impressive". We can keep painting the air with carbon dioxide but what we have is pretty much what we are going to get.
