Visualizing the “Greenhouse Effect” – Atmospheric Windows

Watts Up With That? ^ | February 28, 2011 | Guest post by Ira Glickstein

[Ernest_at_the_Beach]

A real greenhouse has windows. So does the Atmospheric “greenhouse effect”. They are similar in that they allow Sunlight in and restrict the outward flow of thermal energy. However, they differ in the mechanism. A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because “greenhouse gases” (GHG) absorb outgoing radiative energy and re-emit some of it back towards Earth.

The base graphic is from Wikipedia, with my annotations. There are two main “windows” in the Atmospheric “greenhouse effect”. The first, the Visible Light Window, on the left side of the graphic, allows visible and near-visible light from the Sun to pass through with small losses, and the second, the Longwave Window, on the right, allows the central portion of the longwave radiation band from the Earth to pass through with small losses, while absorbing and re-emitting the left and right portions.

The Visible Light Window
To understand how these Atmospheric windows work, we need to review some basics of so-called “blackbody” radiation. As indicated by the red curve in the graphic, the surface of the Sun is, in effect, at a temperature of 5525ºK (about 9500ºF), and therefore emits radiation with a wavelenth centered around 1/2μ (half a micron which is half a millionth of a meter). Solar light ranges from about 0.1μ to 3μ, covering the ultraviolet (UV), the visible, and the near-infrared (near-IR) bands. Most Sunlight is in the visible band from 0.38μ (which we see as violet) to 0.76μ (which we see as red), which is why our eyes evolved to be sensitive in that range. Sunlight is called “shortwave” radiation because it ranges from fractional microns to a few microns.

[cripplecreek]

Can’t I just visualize whirled peas and be done with it?

[TigersEye]

Even though estimates of climate sensitivity to doubling of CO2 are most likely way over-estimated by the official climate Team, it is a scientific truth that GHGs, mainly H2O but also CO2 and others, play an important role in warming the Earth via the Atmospheric “greenhouse effect”.

Maybe it's semantic nit-picking but GHGs and "greenhouse effect" don't warm anything. It retains warmth that is created by another source.

When you cover yourself with a blanket the blanket doesn't actually create any heat.

[Ernest_at_the_Beach]

Hey,...we are getting our own window to ...minds at work.

Be sure and look thru the comments.

Not all agree ...

[Ernest_at_the_Beach]

Hmmm....

Well a blanket warms you because it keeps the Heat from the body escaping.

[TigersEye]

Yes, it is well accepted English to say that a blanket “warms” you but I would expect a scientist to be a little more particular in his use of words. I did say that I might be nit-picking semantics.

[E. Pluribus Unum]

[E. Pluribus Unum]

[E. Pluribus Unum]

[Pearls Before Swine]

From your graph, it looks like temperature leads CO2 concentration, possibly causing it. The AGW crowd says it’s the other way around.

[piytar]

CO2 has a relatively small absorbance in two regions of the spectra (4.2 um and ~14 - 16 um). Photons emitted from the ground at these wavelengths are almost completely absorbed in the first dozen or so meters of air. Those photons are then re-emitted across the spectra and interact further with the atmosphere.

What does that mean? If the CO2 concentration in the air went up 200%, all it would change is how low above the ground the 4.2 um and ~14 - 16 um photons were absorbed. That’s it. Wouldn’t change a dang thing about total heat retention by the atmosphere. Nada. Zilch. Nothing.

In order to alter the CO2 mechanism significantly, we’d have to reduce CO2 levels to a hundredth of where they are now. Of course, by then, all the plants would die (plants need CO2 to live) and then so would we.

Don’t get me wrong: CO2 is a greenhouse gas without which our Earth would be much colder. However, any variation in CO2 concentration that significantly affected the total heat retention of the atmosphere would be so vast as to radically alter or destroy life on this planet all by itself. PERIOD.

Short version: AGW theory isn’t science, it’s marxism. Again, PERIOD.

[steelyourfaith]

 

Beam me to Planet Gore !

[piytar]

Actually, I shouldn’t have said “re-emitted across the spectra.” Other mechanisms - some of which are discussed in the article - transfer the energy of these photons to other molecules which emit the energy at different wavelengths, to kinetic energy (Brownian motion), etc. Of course, some of the photons are re-emitted at the same frequency, and some of those photons go up to encounter CO2 at higher elevations. However, once you get about a dozen meters up, very few of the photons at 4.2 um and ~14 - 16 um are left, which was my point.

[LibLieSlayer]

Do you know the difference between global warming and catching your wife giving a lewinsky to your former best friend... while telling you that “It is not what it looks like”? Absolutely nothing.

LLS

[E. Pluribus Unum]

From your graph, it looks like temperature leads CO2 concentration, possibly causing it.

Think about a cold versus hot carbonated beverage.

The colder the liquid is, the more CO2 it can dissolve.

The hotter it is, the more CO2 evaporates into the atmosphere.

Atmospheric CO2 IS a result of temperature, not a cause.

[Pearls Before Swine]

I’m not arguing with you... just noticing the lead/lag relation clearly depicted on the graph!

[tubebender]

I can grow really great veggies in my greenhouse if I add extra CO2

[Ernest_at_the_Beach]

Tell that to a politician...see if it registers.

[BillM]

Monday, February 28, 2011

Simple Chemistry and the Real Greenhouse Effect.
 
 
Truths:

1. Most of the Sun’s radiation that gets to the Earth’s lower atmosphere passes through substantially unabsorbed.

2. Most of the radiation is then absorbed on contact with the Earth’s surface. This includes the majority water and the minority land.

3. Most of the Earth’s surface is either water or moist vegetation.

Most of the radiation from the sun is converted to infrared wavelengths at or near the surface.

The water molecules absorb the infrared radiation causing increased vibration within the individual water molecules. This is converted into translational energy during intermolecular collisions.

Water is an unusual compound. Its molecular weight (18) is .64 times that of nitrogen (28) and .56 times that of oxygen (32). Water should by all rights be a gas.

 

Real Energy Transfer Click Here

[TigersEye]

No Smoking Hot Spot (The Australian)

The missing hotspot (JoNova)

Those two articles take Greenhouse Theory at face value and by the criterion set up in the theory itself finds no evidence of warming on the basis of greenhouse effect.

The Hidden Flaw in Greenhouse Theory

Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

Harvard astrophysicist dismisses AGW theory, challenges peers to 'take back climate science'

It Is Impossible For A 100 ppm Increase In Atmospheric CO2 Concentration To Cause Global Warming

Simple Chemistry and the Real Greenhouse Effect.

Those five articles each show that Greenhouse Theory has no basis in reality due to a direct conflict with the known laws of physics. No wonder the smoking gun "hotspot" can't be found.

Claim That Sea Level Is Rising Is a Total Fraud

That article pretty much puts the kibosh on any serious trend of planetary warming from any cause. Think about it. If there is absolutely no sign at all of rising sea levels how could the planet be warming? Beyond the centuries long slow warming of the earth and rising of the seas of course. But that is only a few millimeters per century due to the inter-glacial period we are in.