The reason this is so is because if you bring up how CO2 functions in a political debate it would destroy people's arguments that man-made global warming is a threat. So these 'inconvenient truths' are kept carefully hidden from most folks.
I can explain it to you. It is, in fact, very simple.
Here is how it works:
CO2 is normally considered a transparent, colorless gas. It's transparent to us and having a lot of it in the atmosphere is not going to impact our ability to see or whatever. To us it is transparent. Except... it's not really transparent. Not at all frequencies of light.
As you know when something is 'black' to us it absorbs all available light frequencies. When something is 'red' to us it absorbs all the frequencies except the red ones. When something is 'white' it reflect backs all frequencies. etc etc. So as you know on a sunny day a white surface is generally going to be cooler then a black surface. Any child can attest to this through experience.
So that is something that is easy to understand.
The next part is harder to understand:
Things that are 'hotter' emit light that is higher frequency then cooler objects. People use this to describe the 'whiteness' of light, read through the following article:
What they do not explain in that wikipedia color is how people came up with the term '5000 K' whiteness or whatever. The 'color temperature' is based on what color black iron is when heated up to that temperature. So when you heat cast iron up to 5000 degrees then it is more orange-ish. When you heat it up to 9000 K degrees then it becomes much more blue-ish white.
We can see this in the colors of the stars. Our sun is a yellow sun. The reason this is is because it's in the middle-hotness. Blue stars burn much hotter then our sun does. Red stars burn much cooler..
If you understand how radiation is created then it's easy to understand. When something is hotter it is because the atoms in it is moving much faster. The hotter the objects the faster the atoms move. So those atoms moving and vibrating impact what sort of radiation they emit.
So just remember this:
Hotter objects emit higher frequencies.
Cooler objects emit lower frequencies.
So what does this have to do with CO2 and global warming!?!?
CO2 is colorless and transparent EXCEPT for some infrared frequencies.
It is _BLACK_ when it comes to certain very specific infrared colors.
Infrared is a cool color. It is light generated by relatively cool objects. We don't see it, but we are emitting infrared light right now. This is why infrared cameras can see in the dark. They can see the light being emitted by cool objects. If we heat things up to higher tempuratures then that makes hotter light. That is why we can see the light from light bulbs...
putting it all together:
Our Sun emits 'HOT' light. That light travels through the atmosphere and heats the surface of the planet. The CO2 is mostly transparent to the light energy emitted from the sun.
The surface of the planet heats up and reflects back infrared light. This infrared light is a 'cooler' light, but it still has lots of energy. This energy is part of what makes the hot surface feel hot on a sunny day without touching it. However from the infrared light reflected back from the earth... certain very specific frequencies it absorbs that infrared. It is not transparent to those specific frequencies. So CO2 absorbs the specific infrared frequencies and converts that to heat.
I say 'specific' infrared frequencies, because it does not absorb most of it. It cannot. It can only absorb certain specific frequencies.. which is why things like infrared cameras still work.
THAT is how CO2 makes the earth warmer.
CO2 makes the earth warmer because it absorbs certain infrared frequencies being reflected back into space by the surface of the planet.
That is how CO2 works, that is why they call CO2 a 'greenhouse' gas.
Here is the fun part:
So it would _seem_ that the more CO2 you have the more infrared light it absorbs and the hotter it will make the atmosphere. This is very true.
The more CO2 you have the hotter it is going to get. _PERIOD_. There is no debating this. It's a fact.
BUT WHAT THE GREENIES IGNORE IS THIS:
But why is it not dangerous? Why is having more CO2 not a threat to the earth and humanity? If having more CO2 makes things hotter, then why does having more and more CO2 cause a huge amount of problems?
THEY IGNORE THE AMOUNT CO2 CONTRIBUTES.
We already have enough CO2 that pretty much all of the infrared energy that CO2 can convert to heat is already converted to heat. At about ten feet off the ground 99% of the infrared energy is already absorbed by CO2 and converted to heat.
It does not matter how much more CO2 we have because it's not going to be able to squeeze any more energy from infrared radiation. The 'greenhouse effect', the insulating nature of CO2 is completely used up at that point. Now the amount of energy that CO2 absorbs is actually very significant. It's very important. If we lost a lot of CO2 then we would be a lot cooler. But the effect of having more CO2 then we have now is not that great.
The amount heat that CO2 contributes is on a logarithmic scale. It has diminishing returns. Going from zero CO2 to a tiny amount of CO2 has a HUGE impact. But going from lots and lots of CO2 to 4% more CO2 has almost no impact at all.
Look at it like mixing white and black paint:
If you have just a tiny bit of black in a white then that makes a very light gray. Almost all the light is still being reflected back.
The more black you add to the darker the color gets. So more and more light is being absorbed.
However eventually you get to the point were you have lots of black and just a tiny bit of white. You then just have a 'black' color. Adding more and more black color is not going to make it any darker in any noticeable way. It just won't get any darker.
This is the way it is with CO2. Those infrared frequencies that get converted to heat are almost all converted. Double or tripling the amount of CO2 is not going to make much of a difference. It is already doing all the work it can ever possibly do.
A) Man's activity creates lots of CO2 == FACT
B) Having more CO2 in the atmosphere makes things hotter == FACT
A + B) Man's activity makes things hotter == FACT
Man's activity is not contributing _that_much_. We are talking about fractions of a degree. The amount of CO2 in the atmosphere and the temperature changes we see CAN NOT BE EXPLAINED BY CO2!!!!
Man's creation of CO2 can NOT be the cause of global warming!