It's to do with energy getting absorbed and released, but how does this create a greenhouse effect?

And how does 2x Co2 cause more warming than 1xCo2?

Things radiate light at different wavelength depending on their temperature (Wien's Law). Hot things, like the sun, radiate at short wavelengths (visible light, UV, shortwave IR), while relatively cool things, like the Earth, radiate at long wavelengths (longwave IR). Most of the atmosphere is transparent to the longwave IR, so if the atmosphere consisted only of those gases (Nitrogen, Oxygen, etc.) all that energy being radiated by the Earth would escape into space, and the Earth would be MUCH cooler. It would pretty much be a giant snowball.

Greenhouse gases (water vapor, carbon dioxide, etc.) absorb longwave IR, then radiate that energy back in all directions. If you put some of those greenhouse gases into the atmosphere, they'll absorb some of that energy that would have escaped to space, and they send it back toward the surface. As a result, the Earth is the pleasant place we know that is warm enough for liquid water to exist on the surface. If you took away either the water vapor or the carbon dioxide that would be enough to turn the Earth back into a snowball, hence we need both in the atmosphere.

The more greenhouse gases you have in the atmosphere, the more energy you send back toward the surface, and the warmer the planet will be. That's why 2x CO2 will make the planet warmer.

Some people may claim that CO2 is "saturated" and that adding more will make no difference. This is pure nonsense--no scientists believe this and it's easy to debunk.

EDIT for Kano: I've already done that, but sure, we'll do it again. Clearly there is some level of the atmosphere where CO2 is not saturated, since it is not saturated in interplanetary space (actually, it's not saturated at any level, but we'll play along), if it's not saturated at some level, the added CO2 will absorb the IR coming from below. There will always be IR coming from below, because the highest "saturated" level will radiate upward. Consequently increasing CO2 in the higher levels will make a difference, and there is no such thing as "saturation."

EDIT for Sagebrush: You haven't the foggiest idea what you're talking about--actually nobody does, because it's completely incoherent.

Another EDIT for Kano: "Increasingly minute amounts" means nothing. Add CO2 to the atmosphere, and there is more absorption of IR, period. The effect keeps going up and up--it just does not go up linearly. Double the amount of CO2 in the atmosphere, and the effect does not double--it's a good thing, because we would surely all fry then. But it still goes up enough to cause MAJOR PROBLEMS. The graph you give is incorrect for the Earth's atmosphere, because it ignores water vapor, the most important greenhouse gas in the atmosphere.

Another EDIT for Sagebrush: What are you babbling about? The greenhouse effect is real (every earth scientist agrees with this) and keeps us from freezing. If I had a white board, I could show you simple calculations that demonstrate how it works, but it's covered in hundreds of books. Try looking at "Atmospheric Physics" by Fleagle and Businger. I keep hearing deniers use this phrase "heat retention" but you never define it. It's not about "heat capacity", if that's what you think. It's about the infrared absorption spectrum of the molecule.

Greenhouse effect is when heat sent from the sun enters our atmosphere and when it bounces off the earths surface it gets refracted off of the atmosphere so the heat doesn't escape. The problem is that the more CO2 there is the more energy gets trapped. Before when energy would bounce off of the earth most would be trapt but still some of the energy would go back into space. However now more of the heat stays trapped in our atmosphere increasing the overall temperature.

All the carbon dioxide from power plants and cars, etc. builds up, and creates a shield around the earth. When the light passes through to the earth and reflects off the land, it can't get back through, causing all this light, and heat to bounce around, warming the earth, and melting the poles. :) :)

Kano: So tell me, what makes your image correct and my image incorrect?

http://www.csiro.au/~/media/CSIROau/Imag...

It is generally acknowledged, even amongst those scientists who are regarded as skeptics, that each doubling of CO2 will amount to an increase of 3.7W/m^-2. Even the IPCC states this. This amounts to roughly 1deg.C. Now what makes the image you posted correct while scientists that acknowledge AGW, as well as skeptics such as Lindzen, Spencer, and so on, incorrect?

Simple answer to your last question: More mass more heat retention.

The greenhouse effect does not work at all. The true greenhouse effect traps heat because heat waves are longer than light rays. The greenie greenhouse theory is far different from that. The term Greenhouse effect in relation to GW has been proven wrong. It is merely a PR stunt to scare the unwary. This has been proven and proven on this site many times over.

Quote by Ottmar Edenhoffer, high level UN-IPCC official: "We redistribute de facto the world's wealth by climate policy...Basically it's a big mistake to discuss climate policy separately from the major themes of globalization...One has to free oneself from the illusion that international climate policy is environmental policy. This has almost nothing to do with environmental policy anymore."

Quote by Club of Rome: "In searching for a new enemy to unite us, we came up with the idea that pollution, the threat of global warming, water shortages, famine and the like would fit the bill....All these dangers are caused by human intervention....and thus the “real enemy, then, is humanity itself....believe humanity requires a common motivation, namely a common adversary in order to realize world government. It does not matter if this common enemy is “a real one or….one invented for the purpose."

When the greenies come out and admit it a con job, I believe them.

OK Peggy: Prove me wrong. Words are cheap, especially coming from a greenie. You haven't anything to back up your claim. Why don't you argue on an intellectual basis, rather than a back shooting type of junk that you typically do? Either come up with something intellectual and accurate or apologize or I will let everyone know what a ambushing back stabber you are.

Ha! Ha! Peggy, why do you always skirt the question? I asked you, in plain English, to come up with something intellectual. What do you give us all back. A phoney consensus of 75 brainwashed scientists and a book to read. Next you will tell me to study Al Gore. Can you give us all at least one of your pearls of wisdom to prove that you aren't totally intellectually bankrupt.

Maybe the problem is that I speak English. So OK I will ask it in AGW gibberish, . . . . Hmmm, how do you ask a sane question in AGW gibberish? I'll get back to you after I get through reading Dork's book 'AGW for Dummies, because that's all we can fool'.

But here is a typical AGW gibberish answer, maybe you can translate it for me, "Hey man! We got all dis stinkin proof and you got nutin. You are all a bunch of DAs. He. He. You fellas don't know what it means, but we do. It is dirty. We call you a dirty name. He. He. Don't you wish you was as smart as us real thinkers? OK, now how's dis for proof? Al Gore told us, and he don't lie. "

Pegminer says. some people say CO2 is saturated, but this easily debunked. so Pegminer please go ahead and debunk it.

Yes some heat will always be reflected, but increasingly minute amounts to point that it makes no difference.