The problem with the statement "water vapor is 95% of greenhouse effect" is that the primary greenhouse forcing is CO2 and the water vapor is a feedback from that warming.
You are reading too much hype from the IPCC. As regards CO2 the so-called water vapor feedback is a minimal effect due to the overall hydrological cycle and spectral overlap.
Water vapor acts as a field response to any thermal input including solar irradiance as well as ionizing cosmic ray interactions that are modulated by solar magnetic fields. A feedback it may be but of negligible effect where CO2 is concerned due to CO2'a very limited spectral response.
The reality is that CO2 acts more as a feedback to solar input than it does a driver in its own right as solar energy tends to stimulate both biological as well as geological sources of CO2 into the atmosphere.
Any direct warming from CO2 is only ~0.2oC for a doubling of CO2 concentration. The change in temperature CO2 can actually induce at the surface is ~0.3oC figuring an increment in water vapor using standard humidity calculations (assuming no change in preciptation and cloud cover i.e. the hydrological cycle) into account that tend to operate to remove water vapor from the atmosphere.
In point of fact, water vapor interferes with CO2 capacity to aborb IR as water vapor absorption spectrum overlaps CO2's spectral response:
IR absorption overlap between Water Vapor and Carbon dioxide
http://earthobservatory.nasa.gov/Study/ArbitersOfEnergy/
interfering with CO2. The more water vapor in the atmosphere, CO2 actually becomes even less effective than the nominal logrithmic relationship it would otherwise exhibit.
DF = 5.35 ln(C/C0) wm-2 [Myhre et al. 1998, Geophys.Res.Lett., 25:2715-2718]
CO2, because of the prevalance of water vapor in the atmosphere, is limited to only 1/3 of the value it would otherwise have, at the top of the atmosphere, roughy ~1.2w/m2 at surface concentrations as opposed to 3.6-4w/m2, hence actually cooling the upper atmosphere by reradiation to space faster than it can absorb IR at the earth's surface.
"-Importance of Back Radiation at the Surface: It is commonly stated that CO2 absorbs upwelling radiation and then re-emits it to the surface as back radiation. The CO2 bands overlap with water vapor bands whose opacity is so large that most of the back radiation from CO2 is absorbed by the intervening layer of H2O. As a result, the CO2 back radiation at the surface increases by only 1.2w/m2 (Fig.3) as opposed to the 4.3w/m2 tropopause radiative forcing.
(ii) Response at t = t0+ few months: The stratosphere cools and comes into a new radiative equilibrium with the CO2 rich atmosphere, which reduces the increased downward emission at the tropopause by a few tenths of w/m2 (Fig. 3). The Q after the stratosphere has adjusted is:
Q(t=t0+ few months) ~ 4.2w/m2
This adjusted forcing is the number used in most assessments (including IPCC)."
Add ontop of this the fact that additional water vapor put into the atmsphere tends to increase low level cloud cover which actually acts to cool the surface by absorbing high altitude IR and reemitting upward as broadband blackbody radiation (as opposed to the narrow bands where CO2 can absorb IR) and reflecting solar visible light back to space, the net response is actually a negative feedback to CO2 as opposed to a positive one.
"The surface of the earth does not cool primarily by infrared radiation. It cools mainly through evaporation.7 Most of the evaporated moisture ends up in convective clouds (clouds with strong vertical currents carrying the air and its contents upward, as opposed to layered clouds, which form and stay at a particular level) where the moisture condenses into rain. Just as evaporation cools, the condensation of watervapor heats, and the atmosphere realizes most of this heat at altitudes >5km. It is at these heights that the atmosphere must balance the heat deposited by convection from the surface through cooling by thermal radiation. It is worth noting that, in the absence of convection, pure geenhouse warming would lead to a globally averaged surface temperature of 72oC given current conditions (Moller and Manabe 1961). Our current average temperature, 15oC, is actually much closer to the black body temperature temperature (-18oC), than to the pure greenhouse result.8 The relative ineffectiveness of the greenhouse effect is due to convection which carries heat past the bulk of watervapor (which has a characteristic scale height of about 2km), and to large-scale meridional heat transport which carries heat from the moist tropics to the less moist higher latitudes. Because of this transport, it is primarily the distribution of infared absorbers above 5km (rather than below 5km) that is important for containing the heat carried away from the earth's surface (Lindzen et al. 1982)."
*** SNIP ***
"In the meantime greenhouse effect is not nearly as straight forward as is commonly stated."
--- Richard Lindzen (1990) Some coolness concerning global warming. Bull. Amer. Met. Soc., 71, 288-299."Even if all other greenhouse gases (such as carbon dioxide and methane) were to disappear, we would still be left with over 98 percent of the current greenhouse effect." Cato Review, Spring issue, 87-98, 1992;
OTOH, Water Vapor responds across a very broad spectrum, much greater than that of CO2 reponding into the near infrared and down through microwave regions of the spectrum and is a factor for all thermal input regardless of source.
In the end there are many factors involved.
Indeed there are as described above.
and the twin approaches here at FR (discredit CO2 and toss around new forcings out of context) is not particularly convincing to me.
I doubt anything is particularly convincing to you. You have crystalized your views so I hardly figure you to change your mind with information running contrary to the stance you have convinced yourself to take.
OTOH, other people need to recognize there is more to the science than what is coming out of the UN/IPCC political machine's bait and switch routine driving the current charge over the lemming's cliff.
An Economist's Perspective on Climate Change and the Kyoto Protocol,
by Ross McKitrick. November 2003
http://www.lavoisier.com.au/papers/articles/McKitrick.pdfThe 1992 UN Framework Convention on Climate Change (UNFCCC) defined "climate change" as follows:
"Climate change" means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
( http://unfccc.int/index.html )The recent Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) defined it differently ( http://www.ipcc.ch/ ):
Climate change in IPCC usage refers to any change over time, whether due to natural variability or as a result of human activity.
This is a very important difference: The IPCC is looking for signs of any change, whereas the policy instruments prescribed by the UNFCCC are not triggered unless it is a particular kind of change: that attributable to human activity. When IPCC officials declare that "climate change" is for real, this is about as informative as announcing that the passage of time is for real. Of course the climate changes: if it didn't Winnipeg would still be under a glacier. But the fact that the last ice age ended doesn't imply that the policy mechanisms of the UNFCCC should kick in. That's the problem with the ambiguity over the term "climate change"-and it seems to trip up a lot of people-accepting the reality of "climate change" does not mean accepting the need for policy interventions. And denying that global warming is a problem requiring costly policy measures is not the same as denying "climate change."
http://www.pacificresearch.org/pub/cap/2003/cap_03-02-20.html
"The Economist, which provides the best environmental reporting of any major news source, carried a small story last week about a simple methodological error in the latest U.N. global warming report that has huge implications. The article, "Hot Potato: The Intergovernmental Panel on Climate Change (IPCC) Had Better Check Its Calculations" (February 15 print edition), reviews the work of two Australian statisticians who note an anomaly in the way the IPCC estimated world carbon dioxide emissions for the 21st century."
......
"The IPCC's method has the effect of vastly overestimating future economic growth (and, therefore, CO2 emissions) by developing nations. The fine print of the IPCC's projections, for example, calls for the real per-capita incomes of Argentina, South Africa, Algeria, Turkey, and even North Korea to surpass real per-capita income in the United States by the end of the century. Algeria? North Korea? The IPCC must be inhaling its own emissions to believe this."