I do not know what the net impact of H2O vs. CO2 is. (How many degrees increase in surface temprature for a given increase in a particular greenhouse gas?)
Climate Catastrophe, A spectroscopic Artifact?
Conclusions
It is hardly to be expected that for CO2 doubling an increment of IR absorption at the 15 µm edges by 0.17% can cause any significant global warming or even a climate catastrophe.
The radiative forcing for doubling can be calculated by using this figure. If we allocate an absorption of 32 W/m2 [14] over 180º steradiant to the total integral (area) of the n3 band as observed from satellite measurements (Hanel et al., 1971) and applied to a standard atmosphere, and take an increment of 0.17%, the absorption is 0.054 W/m2 - and not 4.3 W/m2.
This is roughly 80 times less than IPCC's radiative forcing.
If we allocate 7.2 degC as greenhouse effect for the present CO2 (as asserted by Kondratjew and Moskalenko in J.T. Houghton's book The Global Climate [14]), the doubling effect should be 0.17% which is 0.012 degC only. If we take 1/80 of the 1.2 degC that result from Stefan-Boltzmann's law with a radiative forcing of 4.3 W/m2, we get a similar value of 0.015 degC.
Consider, for example, the study of Fischer et al. (1999), who examined trends of atmospheric CO2 and air temperature derived from Antarctic ice core data that extended back in time a quarter of a million years. Over this extended period, the three most dramatic warming events experienced on earth were those associated with the terminations of the last three ice ages; and for each of these climatic transitions, earth's air temperature rose well in advance of any increase in atmospheric CO2. In fact, the air's CO2 content did not begin to rise until 400 to 1,000 years after the planet began to warm. Such findings have been corroborated by Mudelsee (2001), who examined the leads/lags of atmospheric CO2 concentration and air temperature over an even longer time period, finding that variations in atmospheric CO2 concentration lagged behind variations in air temperature by 1,300 to 5,000 years over the past 420,000 years.
The major role of water vapor in the "global warming" debate is that the hydrostatic equilibrium can be shifted by increasing CO2, not that we could ever dump enough H2O into the atmosphere to make a difference.
We don't dump enough CO2 into the atmosphere to make a difference either. Contribution of mankind to the total greenhouse gas balance is 0.26%.
Adding up all anthropogenic greenhouse sources, the total human contribution to the greenhouse effect is around 0.28% (factoring in water vapor).
Kyoto, even if imposed equally on all countries around the world, would reduce total human greenhouse contributions from CO2 by about 0.035%.--Which is less than the natural variability of Earth's climate system.
"There is no dispute at all about the fact that even if punctiliously observed, (the Kyoto Protocol) would have an imperceptible effect on future temperatures -- one-twentieth of a degree by 2050."--Dr. S. Fred Singer, atmospheric physicist Professor Emeritus of Environmental Sciences at the University of Virginia, and former director of the US Weather Satellite Service; in a Sept. 10, 2001 Letter to Editor, Wall Street Journal.
1/20th of a degree C folks!
Thanks, I think. I'm still not sure I understand anymore than I did before. I understand the basic physics, to a first order, it's the conclusions that are difficult understand. People have spent their whole lives studying climatology and atmospheric physics and are not sure what conclusions to reach.
The non-physical problem is that people with an agenda will trumpet conclusions on one side or the other of the argument. This is an intellectually dishonest and tendentious approach and is contrary to the scientific approach. Personal bias can creep in and color the results. It is difficult for anyone to accept facts contrary to cherished beliefs. The "scientific" approach is intended to remove personal bias from observations and conclusions.
Global warming is too inviting an opportunity for some people, -neoluddites, power mad politicians, tenured communists, you get the drift - not to seize on to promote their agendas. Few of them even understand the basic physics "to a first order". They see this "docrine" as a holy writ, they rehearse its catechism and become more Catholic than the Pope, without only vaguest idea of what they are talking about. Celebrity poseurs in the media and public life fall in line in legions. (At one time - prior to Ptolemy and long before Columbus - "everyone" knew the Earth was flat. Few in the media today can cite any direct evidence for believing that the Earth is round, other than photographs from space. How can one take them seriously when they talk about global warming.)
The danger is, that in recognizing the shallowness of the proponents, we fall into the same trap. The facts are elusive, conclusions tenative. I suggest keeping an open mind. Just because Jane Fonda believes something to be true is not scientific proof of its falsity. Just generally a strong inference.