How does the Greenhouse effect work? What's special about CO2?

It is very strange as man made CO2 makes up a tiny minute fraction of greenhouse gas therefore it is quite amazing that man made CO2 can make such a huge difference to future global temperatures as predicted by the global warmers. I for one can't wait to see a real hard answer to this one and not all the usual gibberish I have probably heard before! Moreover, atmospheric carbon dioxide levels, currently only 350 parts per million have been over 18 times higher in the past at a time when cars, factories and power stations did not exist — levels rise and fall without mankind’s help. 96.5% of all carbon dioxide emissions are from natural sources, mankind is responsible for only 3.5%, with 0.6% coming from fuel to move vehicles, and about 1% from fuel to heat buildings. Yet vehicle fuel (petrol) is taxed at 300% while fuel to heat buildings is taxed at 5% even though buildings emit nearly twice as much carbon dioxide! A report in the journal ‘Science’ in January of this year showed using information from ice cores with high time resolution that since the last ice age, every time when the temperature and carbon dioxide levels have shifted, the carbon dioxide change happened AFTER the temperature change, so that man-made global warming theory has put effect before cause — this shows that reducing carbon dioxide emissions is a futile King Canute exercise! What’s more, both water vapour and methane are far more powerful greenhouse gases than carbon dioxide but they are ignored. The planet does not need saving, but taking this on anyway, removing every car from every road in every country overnight would NOT produce any change in the carbon dioxide level of the atmosphere and in any case it is pointless trying to alter climate by changing carbon dioxide levels as the cause and effect is the other way round — it is changes in the activity of the Sun that cause temperature changes on earth, with any temperature rise causing carbon dioxide to de-gas from the oceans. If you don't believe me listen to a leading American atmospheric physicist, Professor Emeritus of environmental sciences at the University of Virginia, specializing in planetary science, global warming, ozone depletion, and other global environmental issues. He was a Special Advisor on space developments to President Eisenhower and the first Director of the National Weather Satellite Service Center. He is President of the non-profit Science & Environmental Policy Project, author of Hot Talk Cold Science: Global Warming's Unfinished Debate, Unstoppable Global Warming (NY Times Bestseller), and editor of Nature, Not Human Activity, Rules the Climate... http://www.examiner.com/examiner/x-33398-LA-Public-Policy-Examiner~y2009m12d30-Climate-Change-101-Does-carbon-dioxide-cause-global-warming http://scienceandpublicpolicy.org/images/stories/papers/scarewatch/no_it_wont.pdf

No significate role of CO2 as a greenhouse gas. Water vapor (cloud cover) is 98% of the greenhouse effect. http://www.sciencedaily.com/releases/2009/12/091230184221.htm

Benjamin has got it right. It's called the physics of grey body radiation and has been understood for about 150 years. The surface emits infrared because it's warm. CO2 absorbs infrared, and re-emits it, in a kind of relay process until you get near enough the top of the atmosphere and it gets re-emitted into space. The more CO2 you have, the higher you have to get before the emitted infrared gets a clear run that lets it out to space. The higher you get in the atmosphere, the colder, so the higher the level from which re-emission occurs, the less energy is re-emitted. This means that more energy is absorbed from sunlight than is emitted as infrared, so the Earth warms up. Equilibrium is only restored when the Earth has reached a higher temperature. Also, as the Earth warms, more water vapor is absorbed into the atmosphere. As peter.am says, without understanding the implications, water vapor is also a greenhouse gas. So the water vapor gives a positive feedback loop, magnifying the CO2 effect. Edit: richie mentions Fred Singer. Fred Singer is a mastermind of the denialist campaign. He generated an imitation scientific paper, styled after Proc. Nat Acad. Science, which arrived in my mailbox and that of my colleagues. YHou had to look hard to see it was not the real thing. He also consulted with the tobacco companies about how to raise doubts about the harm done by second hand smoke. A lot of people know this. No wonder r. mentioned his rather old credentials but not his name.

Other gases do it also. Some are even more potent than CO2.

It doesn't reflect heat, it absorbs it and then emits it. It can absorb heat because of the atomic structure of a CO2 molecule. Heat is transferred in the infrared radiation frequency range. The atomic structure of CO2 vibrates over some of the IR frequency range which heats it up. Water vapor (H2O) molecules also have this property as do numerous other less abundant atmospheric gases.

i can only give you a simple answer, since i am not a scientist. the CO2 forms sort of a layer in the atmosphere which keeps warmth down on and near the ground

Nothing. The biggest greenhouse gas is water vapour. Stop that if you can.

Co2 is a very minor greenhouse gas , the major one being water vapour which is responsible for over 95% of the greenhouse effect. Whats special about the non pollutant co2 is that we exhale it and what we are seeing amongst other things is the beginnings of the basis of a tax on breathing which has long been a fantasy of the ruling elite.

It doesn't reflect heat. It is special because the carbon oxygen bonds bend and stretch and the energy that is required to do that is equal to the energy in a photon of thermal radiation. It doesn't absorb all heat. In fact, its absorption spectrum only includes 8 percent of the frequencies that leave the earth. Much of that is already absorbed by the much more common water molecules which also absorbs a much wider bandwidth. It doesn't increase the amount of greenhouse effect when you increase CO2 because it is already absorbed to extinction. Most of the heat that can be absorbed from the ground is absorbed in the first 10 meters. Essentially all of it is absorbed in the first few hundred meters. It would get warmer only by shortening the distance that it is absorbed to extinction but that is mitigated by convection and Beer's law which states that there is a logarithmic relationship between absorbance and concentration. It takes more CO2 to get the same effect. Convection has a very large effect as the distance is shortened to where the bands are absorbed to extinction. When the molecule absorbs heat, the bonds bend or stretch. It doesn't reflect the same frequency it absorbed. It if did, that wouldn't be greenhouse warming. Also, since it is absorbed to extinction, there would be no difference from increasing the amount of CO2. The only way that it could make a difference is by warming the atmosphere. That is an important though difficult to understand concept that is seemingly intentionally ignored and distorted by the few alarmists that seem to have a vague grasp of the science. The energy is converted to momentum or heat and the air warms up. Since it absorbs 8 percent of the frequency, only 8 percent is absorbed again with the rest being lost to space or impacting the surface to warm it up in what is called greenhouse warming.