“The greenhouse effect of CO2 is beyond question – a simply(sic) test using a thermal camera, an IR emitter and a chamber in which you can change the CO2 concentration can illustrate this to be a fact. Likewise, we know for a fact that the increase in CO2 concentration is the result of our industrial activity as fossil sourced carbon has a different signature due to being isolated for millions of years. Also, the chemistry behind ocean acidification is equally understood. We also know that over the past 30yrs – the bulk of which have been the warmest on record – solar activity hasn’t matched the global temperature anomaly at all.
These things we know for a fact.
As for the associated warming, no qualified scientist rejects the one degree warming solely related to a doubling of CO2 concentrations – even the hyped up Lindzen. .”
The above is part of a reader comment on my post “Questioning the “Science” that the AGW promoters promote‘” [Whole comment by Moth available on that post]
I had written, in brief: “So the question must be asked, “is the science of the IPCC-based conclusions reliable, unbiased, exact, beyond question, falsifiable (whatever that means), irrefutable and dependable”?”
Thus we have a debate which might be more appropriately published as a new post to give it due respect.
“The greenhouse effect of CO2 is beyond question”! This I cannot accept on face value and will go into a lot of detail to show why. ‘A’ greenhouse effect, maybe, but ‘the’ greenhouse effect, definitely not! Why?, because this statement is being used to justify world-wide financial and social upheaval on the basis that atmospheric CO2 increases are causing destructive global warming. The intended clarification of “a doubling of CO2 relating to a 1 degC warming not being rejected by any ‘qualified scientist’ also requires a challenge. There is reason to suspect that the continuing rise in CO2 emissions is not being accompanied by a corresponding rise in global temperature.
What I believe to be scientific fact, and/or believed by respective and respected, qualified scientists, is as follows:
1. Atmospheric CO2 concentration is roughly 390 ppm = 0.039 % of total atmospheric gasses.
2. Balance of atmosphere, if humidity zero, Nitrogen approx 80%, Oxygen approx 20%.
3. Minute amounts of other gasses, some of them also greenhouse active, we will come to later.
4. Added to this mix is water vapour H2O, varying widely in concentration on a daily basis.
5. If we add clouds to this, the H2O is assumed to be in the droplet form, separately assessed from greenhouse effects, but of major importance.
Greenhouse gasses: (recent, and approx) [important, but excluding H20]
Carbon Dioxide, CO2, 390 ppm, 390,000 ppb; %of total 99.46
Methane, CH4, 1800 ppb; 0.46%
Nitrous Oxide, N2O, 320 ppb; 0.08%
TOTAL: 392,120 ppb
Miscellaneous (CFC’s etc) < 50 ppt and for the sake of this discussion can be ignored.
(ppm = parts per million, ppb = parts per billion, ppt = parts per trillion.)
A hugely dominating proportion of these GHG’s is thus CO2. However their effect on planetary warming is a function of their heat retention, each gas has a multiplying factor to enable their heat retention values to be correctly compared.
CO2, (reference) 1.0, has warming effect 1.0 x 390,000 = 390,000; % warming 74.167
CH4, factor 21; 21 x 1,745 = 36,645; 6.968%
N2O, factor 310; 310 x 320 = 99,200; 18.865%
Total, 525,845; 100%
So, if the known, accepted green house gasses above were on their own, they would provide warming and re-radiation amounts in the relative % proportions shown. The warming and its radiation would emanate in all directions, a certain percentage back to the surface, if warmer than the surface.
CO2 on its own is thus the most significant GHG, to the extent that it is judged here to be about 75% of all GHG’s , neglecting for the moment H2O.
Next we need to look at the GHG levels in the atmosphere. As mentioned above the atmosphere consists basically of nitrogen and oxygen, again neglecting water vapour, to the tune of say 99%, CO2 has the esteemed level of roughly 0.04%.
The CO2 amount is such that the total IR radiation from the earth’s lower altitudes will be only minutely absorbed compared to that which simply passes through and escapes from the atmosphere. Not only that but the CO2 is only effective in absorbing IR radiation at a few small wavelength bands and thus its absorption level is reduced to between 5 and 8%.
Thus, let’s say 10% of the CO2 level of 0.04% of its volume in the atmosphere is effective as a GHG. So at this stage CO2 is trapping 0.004% of the total upward radiation and re-radiating it back to either create warming or to counter some of the upward radiation.
Next we look at H2O which can be at levels up to 80%, but maybe only 20% at the altitudes where the important gas mixing and GH effect is taking place. It is a strong GHG making the total GHG level now at least 20% with CO2 now becoming a proportion of about 5 x 0.004% = 0.02%. of the total GHGs, (maximum).
Mankind’s contribution to this CO2 warming effectiveness is taken to be 100ppm of the 400 = 25% and if doubled, will be 40% of the resulting 500ppm. Even if they are talking about doubling the total CO2 to 800ppm, the contribution to GHG warming is still only 0.04%, at worst, because H2O levels can be much higher. This is the theoretical warming factor.
After all that, when any warming occurs, evaporation from the water at the planet’s surface increases creating increased clouding. This messes up the whole scenario completely as clouds block the original UV heating but do create some GH warming effect at night (ie., reduced loss of heat). Precipitation and further cooling of the earth results. A net negative feedback situation, modifying the scientists’ excessive claims.
Many other factors are relevant to the issue of mankind’s contributions to, and ability to, control planet climate. But it would be surprising if 0.04% contribution to planet warming was a real issue. 0.04% of our temperature in absolute terms (273 + 20 = 293) is still only 0.109 degK.
If a real-life experiment could be set up as suggested, with controlled amounts of CO2 and H2O in air, with known surface simulation, and free of the closed circuit effect of a container, it would be a valuable improvement over what at the moment seems to be ‘computed science’.
I suggest that what are accepted as known facts by the AGW proponents are not universally accepted. Until some real-life experiment proves the claimed relationships, reliance on models which are only man-made assumptions should be judged as such, and not taken to be reliable factual evidence.
To say that pro-AGW scientists are qualified and others are not, is illogical. Reliance on so-called peer review as a measure of scientific validity is demonstrably inadequate. An example that shows it may be of little value – The commenter cites a reference “Knutti and Hegerl (2008)“. Figure 3a shows a diagram labelling 3 levels – ‘most likeley’, ‘very likely’ and ‘likely’, which are labelled in the wrong places. A minor point but it is not difficult to find other issues deserving criticism.
To indicate how the pro-AGW scientists deal with H20 vapour as a GHG, read and wonder about the following:
“Water vapor is a natural greenhouse gas which, of all greenhouse gases, accounts for the largest percentage of the greenhouse effect. Water vapor levels fluctuate regionally, but in general humans do not produce a direct forcing of water vapor levels. In climate models an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. This in turn leads to an increase in the greenhouse effect and thus a further increase in temperature, and thus an increase in water vapor, until equilibrium is reached. Thus water vapor acts as a positive feedback (but not a runaway feedback) to the forcing provided by human-released greenhouse gases such as CO2. Changes in the water vapour may also have indirect effects via cloud formation. Most scientists agree that the overall effect of the direct and indirect feedbacks caused by increased water vapour content of the atmosphere significantly enhances the initial warming that caused the increase – that is, it is a strong positive feedback.( , see B7). Water vapor is a definite part of the greenhouse gas equation even though not under direct human control: IPCC TAR chapter lead author ( Michael Mann) considers citing “the role of water vapor as a greenhouse gas” to be “extremely misleading” as water vapor can not be controlled by humans ; see also  and .”
The IPCC discuss the water vapor feedback .
“It is not really possible to assert that such-and-such a gas causes a certain percentage of the GHE, because the influences of the various gases are not additive. The 1990 IPCC report says “If H2O were the only GHG present, then the GHE of a clear-sky midlatitude atmosphere… would be about 60-70% of the value with all gases included; by contrast, if CO2 alone was present, the corresponding value would be about 25%”.
- Does the greenhouse effect trap heat Venus (wiki.answers.com)
- Koch Bros. Conference: ‘The Many Benefits of Atmospheric CO2 Enrichment’ (littlegreenfootballs.com)
- Nearly Three-Quarters Believe Global Warming Data Falsified (tipggita32.wordpress.com)
- Global Warming Credibility Problem (themoderatevoice.com)
- Global Warming (socyberty.com)
- Open door: the appliance of science and claims of skewed reporting (guardian.co.uk)
- AGW movement is Fraudulent and Politically Driven. (tipggita32.wordpress.com)