The Real 'Inconvenient Truth'

[sunsettommy]

For those who really care to know the basics.It shows very well why CO2 is an overrated Greenhouse gas.It is after all a TRACE gas even with all the increases over a century.

From Junkscience.com,

The Real 'Inconvenient Truth'
Greenhouse, global warming - and some facts

JunkScience.com
April 21, 2006


Given the number of JunkScience.com (http://www.junkscience.com/) readers expressing some confusion over the "greenhouse effect," carbon dioxide, global warming and climate change, we thought it might be a good idea to pull together a page of questions-and-answers, complete with a few nice little graphics explaining the facts.

We thought that since there is long-standing, intense public interest in these topics and that vast sums of public and private monies are being thrown at the much-dreaded "problem" of "global warming," there should be a wealth of quality explanations and graphics to which we can point readers to alleviate their confusion.

That was about the time that our quick project and quiet weekend went awry very quickly.

Who would have thought so many "issue" sites, environment sites and, yes, government sites, could be hosting so much utter garbage on a topic subject to such intense scrutiny? Who could have imagined having to spend several hours wading through searches to find a few simple graphics correctly expressing the greenhouse effect? Who knew that so many blowhards are out there pontificating from complete ignorance?

Some of the bad descriptions appear to be poor efforts at simplifying the material to suit grade school course work and the like, but that does not make them any more acceptable. Obviously a slight rethink of this project was necessary. We will now try to deliver an extremely simplified version of how this greenhouse thing actually works and some indication of what might be expected from what is known about the Earth and what has been measured, rather than simply guessed about. Basic misconceptions that must be addressed include:

Does the Earth's atmosphere primarily behave like an actual greenhouse?


No. The term "greenhouse effect" is unfortunate since it often results in a totally false impression of the activity of so-called "greenhouse gases." An actual greenhouse works as a physical barrier to convection (the transfer of heat by currents in a fluid) while the atmosphere facilitates convection. So-called "greenhouse gases" in the Earth's atmosphere do not act as a barrier to convection so the impression of actual greenhouse-like activity in the Earth's atmosphere is wrong.

Supplemental, April 25: A couple of people have written challenging whether physical greenhouses function as convection barriers since they do radiate and so does the atmosphere - apparently we need to expand on this point. To begin with, a physical greenhouse is simply a contained subset of the atmosphere - it is not bounded by the near-vacuum of space as is the planet's atmosphere and so has rather different properties. The proof that convection containment is critical to the function of physical greenhouses is that it is possible to create structures with similar radiative properties, one which allows convective activity between the structure and unconstrained atmosphere and one which does not. Only the structure constraining internal-external convection will function as an effective greenhouse. Greenhouse gases categorically do not inhibit convective activity and so are not like a physical greenhouse.

(a lot more)

http://www.junkscience.com/Greenhouse/

Maybe Markus and Bob will admit that their narrow view is why they miss what is known.That Atmospheric CO2 is an overrated Greenhouse gas.

I wonder why people fall for it so stupidly since the basic scientific knowlege of CO2 clearly shows its minor role in any warming trends.

The link shows very well why CO2 can not promote any significant warming.It has to do with SATURATION levels of absorption.

The temperature effect of atmospheric CO2 is LOGARITHMIC
and limited by radiative window saturation -- once a radiative waveband is fully absorbed adding more absorbers has zero effect.


Just read the link and find out.

[sunsettommy]

A sample from the link Junkscience.com I posted above:

I bolded in RED to point it out,

So, greenhouse is all about carbon dioxide, right?


Wrong. The most important players on the greenhouse stage are water vapor and clouds. Carbon dioxide has been increased to about 0.038% of the atmosphere (possibly from about 0.028% pre-Industrial Revolution) while water in its various forms ranges from 0% to 4% of the atmosphere and its properties vary by what form it is in and even at what altitude it is found in the atmosphere. In simple terms, however, the bulk of Earth's greenhouse effect is due to water vapor by virtue of its abundance. Water accounts for about 90% of the Earth's greenhouse effect -- perhaps 70% is due to water vapor and about 20% due to clouds (mostly water droplets), some estimates put water as high as 95% of Earth's total greenhouse effect. The remaining portion comes from carbon dioxide, nitrous oxide, methane, ozone and miscellaneous other "minor greenhouse gases." As an example of the relative importance of water it should be noted that changes in the relative humidity on the order of 1.3-4% are equivalent to the effect of doubling CO<SUB>2</SUB>.
http://www.junkscience.com/Greenhouse/absorbspec_small.gif (http://www.junkscience.com/Greenhouse/absorbspec.gif)The adjacent radiation absorption window graphic gives an idea of which molecules absorb various wavelengths. Where the shaded portions completely span between 2 lines it indicates that particular wavelength is fully absorbed and the "window" is saturated (or said to be "closed"). Rather obviously, once a window is saturated adding more gases with the same properties will do nothing. This point seems to cause confusion for some people so perhaps consider multiple shades on a window with each shade blocking half the light coming through - pull one shade and you reduce the light source by half, pull another so you block half the light coming through the first shade, etc.. The effect of each shade diminishes as you keep adding more and eventually you get no additional effect - you have saturated or blocked the radiation window and it makes no difference if you double or quadruple the number of shades again.

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Now I will add this section to bolster what Steve is talking about.

Again from the origional link:

Ah, we've added 2.5% to the greenhouse effect then?

Not exactly, if it were such a simple accumulation, we could easily determine exactly how much Earth would warm from a doubling of atmospheric CO<SUB>2</SUB> (not much) and certainly that would be an improvement on the silly figures bandied about. Theoretically, in a dry atmosphere, carbon dioxide could absorb about three times more energy than it actually does, as could clouds in the absence of all other greenhouse gases -- look at it as there already being "competition" for available suitable longwave radiation (energy these gases can absorb), if you like. Readers should be aware that the temperature effect of atmospheric carbon dioxide is logarithmic (that means there is a diminishing response as you keep adding more, like the additional window shade example, above). If we consider the warming effect of the pre-Industrial Revolution atmospheric carbon dioxide (about 280 parts per million by volume or ppmv) as 1, then the first half of that heating was delivered by about 20ppmv (0.002% of atmosphere) while the second half required an additional 260ppmv (0.026%). To double the pre-Industrial Revolution warming from CO<SUB>2</SUB> alone would require about 90,000ppmv (9%)

but we'd never see it - CO<SUB>2</SUB> becomes toxic at around 6,000ppmv (0.6%,

although humans have absolutely no prospect of achieving such concentrations).