Anyway, the amount of water vapor in the atmosphere tends to increase with increasing temperature. Since water vapor is a greenhouse gas, this is a positive feedback. Adding carbon dioxide to the atmosphere causes some warming. This warming adds water vapor which causes more warming. The reason why this doesn't cause runaway warming is because the temperature change required to cause water vapor to double is greater than the temperature change caused by such a doubling.
Since water vapor does most of the heavy lifting, it could be compared to a bulldozer, and carbon dioxide could be compared to the operator of the bulldozer.
The amount of water vapor in the atmosphere primarily depends on two factors. Heat and pressure. The more heat, the more water vapor the atmosphere holds. With pressure, it's the opposite. Lower pressure systems hold more water vapor. Water vapor is considered more or less a constant. The amount of water vapor in the entire atmosphere does not fluctuate too much, even though it fluctuates a lot regionally. Just like the amount of energy from the sun does not fluctuate much, at least in the short run. This is why a "lesser" greenhouse gas like carbon dioxide can have a greater impact. CO2 is steadily rising. If water vapor were to rise like CO2 is, then the warming effect would be worse. Also, increasing CO2 warms the atmosphere a bit, which results in slightly more water vapor in the entire atmosphere (warm air holds more water vapor), which results in even more warming. This is a positive feedback effect, and even though the extra water vapor is directly causing more of the warming, the CO2 is responsible for the vapor (in this case at least).
Not ignoring it. Understanding that the additional warming created is insignificant and so miniscule that it is a non-factor as a catastrophic change to the climate over 150 years of industrialization. The temperature anomalies empirically show that CO2 increases are a non-factor and that current temperatures are not being influenced by them.
Additionally:
I agree whole heartedly with Brigalow Bloke. It's hard to measure, yet even if it was measurable I doubt that the warming would be very significant. It would be nice if you could provide a real life experiment in side by side greenhouses where air make up was the same except for CO2 concentrations where it can be controlled. 280ppm in one greenhouse and 400ppm in the other and observe the temperature difference at 12 noon. I'd bet that the difference is barely measurable. I would think that science would have already done this.
Um, a large feedback is more important. It changes a system much more than a small forcing unless..
The only significance of a forcing is it is a primary driver. A small forcing can cause a large feedback. or a small feedback. Feedbacks are critical to the AGW hypothesis. Simply doubling the concentration of CO2 will not have a detrimental effect on the earth. If that small warming causes positive feedbacks to kick in- like releasing methane in the permafrost- then you have a problem.
A decent analogy would be putting on the brakes in your car. The force of your foot on the pedal is the "small forcing," a small amount of force which is responsible for causing a much larger feedback- the brake pads pushing against the rotors.
Hmm I think you do not understand what feedback means, if you balance a pencil on its end, a small nudge will alter its balance and gravity will cause it to topple over, that's positive feed back.
If you suspend that pencil by one end like a pendulum and a apply a small nudge gravity will bring it back to its original position, that's a negative feedback.
Does the small forcing of CO2 cause positive or negative feedback's, I guess it must be negative otherwise we would had some warming in the last 17yrs.
From 1976 to 1989 I worked as an analytical chemist on the eastern edge of a small city in Australia. My main job was analysis of air in underground coal mines for safety purposes. Since u/g mine air usually resembles ordinary air pretty closely with small additions of carbon dioxide, methane and carbon monoxide, I used ordinary air to set up my equipment, straight and mixed with calibration gases in known amounts. .
I soon found that CO2 concentration was higher than the literature value I had, which had been printed in 1966. The average I got over a few days was 0.0320%. That is in the southern hemisphere, where CO2 concentrations tend to be lower and more stable than in the northern hemisphere because there are fewer land masses, lower populations and much less industrial activity.
The laboratory was on the eastern edge of a small city about 30km from the coast and winds tended north east to south east most of the time, so I was not picking up CO2 from traffic etc in the city.
Over the next 13 years it crept up to an average over a few days of 0,0345%. These observations were confirmed by another laboratory.
Since the absorption of infra-red radiation by CO2 (or any other compound) increases with concentration in a medium such as air, it is not refutable by any political or religious commentator that absorption of such radiation would also increase over the same period. Increase in such absorption means an increase in air temperatures. If no other factors existed and the quantity of air was known, the increase in temperature of the air would be exactly predictable.
However this is not true of a complex system such as the Earth's atmosphere where the amount of water vapour which also absorbs infra-red radiation is highly variable, and clouds work to trap heat radiated into space but also reflect it coming in from the Sun among other things. Where the balance lies at any instant on a global scale probably can never be calculated exactly. Obviously approximations can be made on the basis of detailed information of CO2 concentrations, humidity, barometric pressure, clouds etc and compared with satellite and ground observations of air temperature.
Whatever the feedbacks, where that balance point is at any particular time, it is not rationally disputable that it is being set higher if CO2 concentrations continue to increase.
There is one thing I'd like to add. Any expressed opinion on this that uses political or religious words, phrases or concepts can be ignored.
In the 1/4 second it took for me to decide to answer this question or go on to the next I came up with a very simple example. Take one quart of water at 34'F. Add 10 gallons of water at 34'F (large feedback). Change is 0. Take one quart of water at 34'F. Add 1 oz of water at 210'F (small forcing). The temperature of the 1qt. 1 oz. of water will rise above 34'F; not much, but more than the 10 gallons of feedback caused.
It is waste of time to argue with hard-core haters and deniers of science here whose arrogance is proportional to their incurable ignorance.
In answer to the question, an example:
In good moderately deep snow conditions, on a short steepish slope, get a basketball-sized snowball rolling nicely downwards and it is likely to at least double in diameter by the time it hits bottom.
A much longer slope with the snow getting deeper and deeper down the hill, will produce no big snowball at the bottom, if you don't start a smallish one rolling from the top.
It is all theoretical, Chem. You can't explicitly explain theory, you can only do so after it has been proven to be a fact. You are not there yet, scientifically or otherwise.
No wonder they call you flunky. That has to be one of the most stupid thoughts I ever heard. A theory can exist because of a bad LSD trip. Facts can't.
Certain Parties seem confused about the roles of CO2 and water vapor as greenhouse gasses. Specifically, they think that because the total warming effect of water vapor is larger than that of CO2, the warming effect of CO2 can essentially be ignored.
Can someone please explain, in simple words, how a relatively small forcing could be more relevant to determining future temperatures than a comparatively much larger feedback? Analogies to generally understood similar phenomena might be helpful, as might links to sites attempting to explain the issue to children.
