Reply to "myself"

Please see my post on this matter, dated 20th June 2006, at http://forum.physorg.com/index.php?showtopic=6077&st=30

AEBanner

This sounds rather like an experimental test, based on the assumptions you're making. You may want to look into how subsequent work has treated this result, however.

From: http://www.engr-sci.org/history/climate/co2.htm

"... A few years after Arrhenius published his hypothesis, Knut Ångström sent infrared radiation through a tube filled with carbon dioxide. He put in as much of the gas in total as would be found in a column of air reaching to the top of the atmosphere. The amount of radiation that got through the tube scarcely changed when he cut the quantity of gas in half or doubled it. The reason was that CO2 absorbed radiation only in specific bands of the spectrum, and it took only a trace of the gas to produce bands that were "saturated" — so thoroughly opaque that more gas could make little difference.(7*)"
...
_____________
7. Ångström (1900); a leading expert dismissing CO2 because of saturation was Humphreys (1913), pp. 134-35; but while denying that doubling the amount in the atmosphere would "appreciably affect the total amount of radiation actually absorbed," he did note that it would "affect the vertical distribution or location of the absorption," Humphreys (1920), p. 58; on CO2 saturation, Schaefer (1905) ...

The CO2 level of the atmosphere is regulated by the water in the atmosphere. CO2 is readily absorbed by water to form carbonic acid H2CO3. The carbonic has a much lower vapor pressure than CO2 and will stay in the water. The rain falls to the oceans, which are slightly alkaline. This neutralizes the carbonic acid to form carbonate and bicarbonate (shells and coral), fixing the CO2 in even lower vapor pressure ways. A chimney stack CO2 scrubber works by the same principles, with CO2 rising up the stack and water raining downward.

If by chance the CO2 was to accumulate to form a greenhouse affect, that means warmer global air. The warmer air means more evaporation of surface water and bigger thunder clouds. The net affect is more water in the atmosphere to rain and scrub out the excess CO2, with the bigger thunderclouds reaching higher into the upper atmosphere to get at the higher height CO2.

The warmer climate and the greater amount of rain due to the higher CO2 also means that more plants are able to grow and last longer. The greater plants density will also increase their rate of CO2 absorption. With all these affects, the tide will eventually change with the CO2 levels gradually dropping. This will lead to cooling.

The lower CO2 and cooling means less evaporated water and less scrubbing of the atmosphere. Relative to the plants the cooler air combined with less rain means less plant growth, less CO2 absorption and forest fires. The latter will help increase the CO2 levels for another cycle.

The models that calculate the rate of terrestrial temperature increase, due to greenhouse gases, assume the solar heat output is constant. Without the sun, greenhouse gases would be a moot point. Isn't it possible that the sun also goes through its own ups and downs, causing the solar thermal output to fluctuate and that the assumed fixed solar output needed to make the greenhouse gas model work, is a naive assumption? It could be correct, but that has yet to be proven.

There are several problems with the theory that CO2 is the sole cause of the rather sudden increase in the temperature of the Earth. Sulfur dioxide tends to counterbalance the effect of carbon dioxide. Increasing obstruction of heat radiating from the Sun is caused by smoke and dust. There has been volcanic activity and many forest fires lately. Heavy metal asteroids have been hitting all of our planets. Anyone who uses a Geiger counter realizes that half the radiation recorded comes from outside the Earth and the other half from the Earth itself. Several articles I have reviewed state that all the planets including Earth contain enough radioactive material to add about a third of the heat to their environment. Nuclear research by Russia and Japan have shown that georeactors are giving off antineutrinos from the Earth's metallic core.
Nuclear reactions increase when neutrons are slowed by water. The magnetic poles appear to represent points in the surface of the Earth that are moving towards the ocean. Thus, the increase in the heat given off by the radioactive core of the Earth may be increasing along the west side of Canada. I have been interested in the probability that a large fragment of heavy metal hit Hudson's Bay in 11,000 BC . This fragment was seen and reported to represent a new moon named after the Leo goddess, Athena. Magus Physician.

The argument that additional CO2 can't warm the Earth's surface is completely bogus. It assumes that all the photons coming from the Earth are at the wavelength intercepted by a particular absorption line of CO2. They aren't. They are spread out across the entire spectrum. If you use a Planck distribution, there are many "windows" for those photons to get through.

And the absorption changes with pressure and temperature. It will be different at each altitude, in predictable ways. When the innermost part of the band is saturated, the edges of the band are not. Thus, in practice, adding more CO2 to the atmosphere does increase the infrared absorptivity of the atmosphere and does warm the ground, as shown by large numbers of experiments.

But let's assume for purposes of argument that it all gets absorbed low down. What will happen to the gases doing the absorbing? They will heat up -- and they will heat up more the more energy they absorb. And they will radiate more as they heat up. This will send more radiation up to the next layer, and more down to the ground -- warming the surface.

A little learning is a dangerous thing. Drink deep, or do not drink, of the Pierian spring.

The Sun experiences perturbations in its orbit. The eccentricity of the Earth's orbit around the sun (from elliptical to circular) has a period of 100k years. The angle of tilt of the Earth's rotation axis varies between 21.5 and 24.5 degrees on a period of 41k years. The precession or wobble of the Earth on its axis has a period of 23k years. Each of these variations effects the amount of solar flux that impact the Earth.

Recent findings regarding the climate history of the planet over the past 600k years vary with matching oscillations, indicating a high probability of correlation with orbital perturbations. This is generally accounted for the interglacial and glacial periods.

Currently, the Earth's climate and orbital status, in contrast with the historical trends, are at a point of highest flux. That is to say, at the current time the Earth is at the warmest stage in this cycle. Bearing in mind that this cycle only varies temperature +/- 4 degrees Celsius, the "Hockey Stick" or really any significant (over 5 degrees) increase in temperature becomes a very compelling argument for abnormality in the climactic cycle, including the potentiality of anthropogenic causes.


Frank Press, "Understanding Earth" 2nd Ed.
California Department of Water Resources, "Impacts of Climate Change", 2006.

Temporary


<img src='http://www.tadau.com/CO2AbsorptionPeak4sinusoidalsides.jpg' alt="test">

Temp

As suggested in my original note, there are at least three sources of heat that effect the termperature of the Earth. The Earth recieves sunlight. Heat from sunlight varies by the relative distance and position of the Earth in relationship to the Sun. The second factor is the degree of reflection of heat from Earth back to the Earth. This heat varies with the dust and gases in our atmosphere. The third factor is the amount of heat generated in the core of the Earth by natural atomic decay of radioactive heavy metals. This last source has been overlooked by most people who have not read the articles on this subject in Discover magazine. My interest in atomic power comes from my familiarity with radioactivity and my study of past history. I have found a source of information concerning the collision of a large radioactive meteorite at Hudson's Bay. This meteorite was first seen in 11,000 BC. It was named after the goddess Athena. It is represented in Egyptian mythology by the Sphinx, and it has been noted in several other religions. Spinning heavy metal meteorites are magnetic, and this one was attracted to the north magnetic pole that was present at that time in Hudson's Bay. The magnetic north pole moves slowly West so that each year it is about 12 degrees closer to the Pacific Ocean. When water seeps into a radioactive pile, the water slows the neutrons so that the heat output increases. Is it possible that this heat is generating steam in the Northern Pacific ocean to increase the rain and snow along our West coast?

Its pretty hard to believe that any STATIONARY process could generate sufficient heat to ALTER the temp of a sufficient part of the Pacific Ocean to cause this warmer water to alter the Earth's climate without the SOURCE of all this extra heat being detected.

Arthur

Thank AD for his comment. Of course it is difficult to believe this might be correct.
Now you realize how surprised I was to read about the lakes in NW USA that usually froze solid and were remaining unfrozen, then I began to wonder. Also, ask yourself where the huge lightning bolt came from that hit Canada and created a diamond mine. Review the mining reports from Canada. There is a huge lump of cobalt up there not to mention gold under the snow, other heavy metals and radioactive ores. Magus Physician

Greenhouse Gas Effect and Carbon Dioxide

This is a revised and extended version of my initial post.

When in energy balance, the Earth radiates from the top of the atmosphere at 235 Watts per square meter (1).

Radiation from the greenhouse gases goes in all directions, and so, effectively, half is radiated out into space, and half is returned to the Earth’s surface and so helps to increase the surface temperature up to a value for which the radiated emission is twice that from the greenhouse gases to outer space, having made allowance for the energy which escapes directly through the ghg layers to space. Thus, the Earth’s surface radiates at 390 W.m^-2

Carbon dioxide has an important absorption peak for infrared photons of almost 15 micrometres, but very little of significance at other wavelengths.

In order to ensure 100% absorption of photons of this wavelength, the surface must be “covered” by sufficient molecules of CO2. Now, the absorption cross section of a CO2 molecule for a 15 micron photon is about 5×10^-22 m^2 per molecule (2), and so the number of molecules required to cover an area of 1 m^2 is 1.0 / (5×10^-22), ie. 2×10^21 molecules per square metre.

Now consider a vertical column of the Earth’s atmosphere based on a square of area 1 m^2.
This air column has a mass of 1.01×10^4 Kg.m^-2.

The mass of the neutron (& proton) is approximately 1.67×10^-27 Kg.
So the mass of the nitrogen molecule is 4.68×10^-26 Kg.
Therefore, the number of N2 molecules in the column is approximately 2.15×10^29.

Now, carbon dioxide is currently present at the level of about 380 ppm by volume, and so the number of CO2 molecules in our 1 m^2 column is about 8×10^25.

Therefore, the 100% cover for the 15 micron photons can be provided 8×10^25 / 2×10^21 times over, ie. 4×10^4 times. Moreover, 100% absorption cover can be provided down to absorption cross sections of about 1.0 / (8×10^25) m^2, ie. 1.25×10^-26 m^2. This is about 1000 times smaller than the smallest spectral lines shown for the 15 micron wavelength region in the HITRAN data to be found at http://vpl.ipac.caltech.edu/spectra/co2pnnlimagesmicrons.htm. The smallest spectral lines shown in this region are at about the 10^-23 m^2 level, and occur within ± 1 micron of the major line, ie between 14 and 16 microns. (Note that the HITRAN ordinate axis is in cms^2.) It follows that the absorption peak in this region must have a flat top, corresponding to 100% absorption of photons, from at least 14 microns to 16 microns wavelength. If still smaller spectral lines occur, too small to be shown in the HITRAN data but greater than 1.25×10^-26 m^2, then the flat top will be wider still.

However, if there are appropriately small spectral lines, there must be a wavelength at which the absorption cross section is sufficiently small for some photons to manage to escape through the carbon dioxide to outer space. At this point, the height of the absorption peak begins to fall from the 100% level, and this proceeds further as the wavelengths are reduced below 14 microns, and increased above 16 microns. This forms the sides of the peak, sometimes referred to as the “shoulders”.


Low level infrared absorption cross sections of carbon dioxide



The diagrams may be enlarged by using CONTROL+SCROLL.
Alternatively, the Windows Magnifier may be used.

In the diagram, ABCD represents a simplified infrared absorption peak of CO2 at 15 microns. The ordinate axis is the power per square meter (W.m^-2) of the Earth’s surface per micron element of wavelength. The horizontal axis is the photon wavelength in microns.

If there are no smaller spectral lines outside the 14 to 16 micron range, as discussed above, this would give vertical sides to the absorption peak in the diagram, and we would get EFCD, which means that extra CO2 could not produce an enhanced GHG effect.

To be realistic, however, we should allow for the possibility that smaller lines do exist on either side, but are too small to be shown (or are too small to be measured). The exact values do not really matter, but together they would produce sloping sides to the peak, simplified as straight lines, AD and BC, in the adjacent 1 micron sections. Still smaller peaks removed yet again by another micron would give an effect too small to be really significant.

The effect of doubling CO2 concentration in the atmosphere

Original peak, at pre-industrial CO2 concentration
The wavelength axis has been considered to comprise 0.1 micron elements, giving 10 steps per one micron element. The power absorbed by the peak ABCD is given by the area under the peak and so, for arbitrary units with 10 units of height corresponding to the 100% absorption level, the flat top, the original area is 300 area units. (A simple, approximate measure can be obtained by adding the ordinate values for each 0.1 micron step.)

Final peak, after doubling CO2 concentration
Suppose that the CO2 concentration is now doubled from pre-industrial levels. The flat top cannot go any higher because it is already at the 100% absorption level. However, the first 0.1 micron element can double from 1 height unit to 2 height units, an increase of 1 height unit, and similarly for the next elements up to and including the fifth one. The increases are shown by the short vertical lines at the left. But the last set of 5 elements cannot double because of the 100% limit. Their increases are shown above the vertical lines. This results in an increase of 25 area units each side, ie a total increase of 50 area units, with the final peak absorbing a power of 350 area units.

Now, from a Planck distribution of the Earth’s radiation spectrum, with the Earth in radiative balance at a surface temperature of 288.0 degK and emitting 390 W.m^-2, we find that the power from a wavelength element of 1 micron, at 15 microns, is 7.43 Wm^-2. This is equivalent to 100 area units in the diagram. So a power increase of 50 area units in real terms is 3.72 Wm^-2.

Therefore, (final power) / (initial power) = 393.72 / 390.0 = 1.009538
Hence, the Absolute temperature of Earth’s surface increases by a factor which is the fourth root of this, (1.009538)^0.25, ie 1.002376, by the Stefan-Boltzmann Law.

So the Earth’s surface temperature becomes 288.68 degK, ie an increase of, say, 0.7 degC.

If conditions were such that the original peak sides sloped linearly over two microns instead of only one, then it can be shown that the temperature increase would be 1.4 degC, but this would seem to be very unlikely in view of the way the amplitudes of the small spectral lines fall off with displacement from the major peak within the closest 1 micron elements. From the HITRAN spectra, this fall-off seems to be at least a factor of 10 per micron.

This simple model using only 10 points each side has been verified by calculating the results for 1000 points each side. Moreover, the simple model has been extended to include 5 one micron sections of assumed small lines on either side, with a fall-off of a factor 10 in each section. The results are shown below.

CO2 Factor Increase_____Surface Temp Rise degC

1.36 present day_________________0.42
1.5____________________________0.54
2.0____________________________0.86


For comparison, an absorption peak with sinusoidal sides has also been considered, as shown below.



CO2 Factor Increase_____Surface Temp Rise degC

1.36 present day_________________0.27
1.5____________________________0.34
2.0____________________________0.50


Conclusion
It is not known whether any small spectral lines exist in the 15 micron region, outside the range 14 to 16 microns, because of limitations in available data. If there are no such lines, then it is difficult to see how additional carbon dioxide can have an enhanced greenhouse effect.

If such small lines do indeed exist, then this could cause an enhanced GHG effect, and for a doubling of CO2 would produce an increase in Earth’s surface temperature of no more than about one degree Celsius.


References
(1)http://stephenschneider.stanford.edu/Clima...hsEnergyBalance

(2)http://vpl.ipac.caltech.edu/spectra/co2pnnlimagesmicrons.htm

Aubrey E Banner
Sale, Cheshire, UK

Interesting post AEBanner!

I noticed that you were banned at another website.You were very civil and just wanted feedback on what you were posting.It is sad that you were trying to get constructive criticism.

They gave up on you so fast!

I am very interested in the CO2 logarithmic effect and the possibility that additional CO2 molecule has a slightly smaller warming power and that over time any more CO2 would produce little additional warming.

I have not read your post with diligence.So if you already answered it that is fine.

Thanks for your effort.

Hi Aubrey!
It's nice that you get sensible figures from a simple model.

However, one shouldn't overview that a simple model can't be exact. For instance, the Earth's ground temperature varies from one point to another, and the radiated power density varies as T^4, so it is necessary to model the temperature distribution (and the heat redistribution) on the Globe to get accurate. Between +30°C and 0°C, the radiated power density varies (nonlinearly!) by a factor of 1.5; replacing that by a mean value is a hard approximation when forecasting temperatures variations of 1K over 300K. Unfortunately, highly computerized 3D models are necessary - but I still appreciate yours.

Did I understand properly that you neglected the absorption by CO2 outside of its spectral lines? The image you posted doesn't appear on my screen, but I found other data elsewhere that tells 15% absorption by CO2 outside its lines. On these frequencies, changing the concentration does have a heavy effect on ground temperature - an effect that won't saturate soon. Doubling this effect would, in a uniform blackbody model, increase the temperature by 9K!

Melting of glaciers and icecaps isn't a matter of modeling and forecasts: you can observe it on older postcards. The induced colour change will heat the Earth more, and this contribution can't be accounted for in a strictly atmospheric model.

You live in Cheshire? May the Gulf Stream be with you for a long time!

Reply to Sunsettommy

Thank you for your kind comments, and please forgive my delay in replying.

I’m afraid I can’t make any useful contribution about the CO2 logarithmic effect you mentioned, except to say that the relevant equations I’ve seen seem to deal with CO2 concentrations, whereas in the real atmosphere I believe we should be dealing with the very numbers of CO2 molecules present, which is a very different matter, and it is the numbers which determine the amount of power absorbed by the gas, about half of which is re-radiated to Earth.

I think you might find my latest effort in this forum interesting, namely “What Enhanced Greenhouse Gas Effect?”

AEBanner

Reply to Enthalpy

Thank you for your comments. Of course you are correct about the need for supercomputers and complicated models, when trying to deal with climate, but I was simply trying to get a measure of the effect of warming produced by CO2.

The major lines at 14 and 15 microns have long been accepted as absorbing all the power emitted from the Earth’s surface within these two wavelength elements. What I wanted to do was to determine the effect of the adjacent regions, sometimes called “side bands”, which give rise to “shoulders” on the absorption peaks. This would include 11, 12, and 13 microns, and 16 microns upwards in wavelength, until the spectral lines are really insignificant, perhaps at about 20 microns or so.

I did not include all these in my post, but I agree these wavelengths cannot be ignored in a full treatment of the effect of CO2. Indeed, an energy balance consideration involving Planck and Stefan-Boltzmann shows that it is necessary for CO2 and/or H2O to absorb 100% of photons from the wavelengths mentioned above if a surface temperature of 288.0 K is to be achieved.

I hope you might find my latest post in this forum interesting, “What Enhanced Greenhouse Gas Effect?”

Constructive comments gratefully received.

AEBanner

One thing that needs to be added to the greenhouse gas models is water vapor. As one easy to see example, if the sky is clear at night the amount of heat radiating into space is high. Greennhouse gases or not won't stop the rate of radiation into space on a clear night. If we add moisture to the air, the amount of radiation will decrease.

Anyone living were frost appears in the fall, usually worries more about frost killing their flowers and shrubs, when the night sky is clear and dry. If it gets a little muddier than usually the first frost is avoided for another night. The greenhouse gases may store extra heat during the day but a clear night can bleed it off.

From this one can see how, if water is not taken into account, greenhouses gases can be over emphasized. The greenhouse gases may get a ball rolling, with the heat adding more water to the atmosphere. The atmospheric water, in turn, can make the nights radiate less heat creating, the illusion that the greenhouse gases are responsible for the entire affect.

Anything that add more water to the atmosphere will cause less heat to radiate at night. For example, all sources that produce CO2 also add water, since these two are the products of combustion. A little extra solar heat will add water. Even terrestrial heat will add water. For example, plate technotics takes energy to occurs. The energy that induce this plate movement come from the heat and pressure in the mantle reaching the surface. Irrigation to water lawns and crops add more water to the atmosphere.

Many communities tell people to help save water by irrigating at night, maybe making otherwise clear nights less able to radiate heat. This is puny but it show how water factors can be at work at the same time. Watering at night is often used to prevent frost. This is a slightly different affect but the water is used for its heat capacitance.

I posted AEbanner's info on a site and I got this reply. Does this make sense? I can't post links, so the links are missing.



You're using a single-slab atmospheric model, the same mistake early-century physicists made.

Let's go over details through a thought experiment: Right now we have some atmosphere which has a temperature profile T(p) which decreases with altitude (with the dry or moist adiabat). Ps is the surface pressure, and Ts = T(Ps) because of heat transfer the surface must be near temperature of overlying air. Now the outgoing longwave radiation (OLR) looks like εσTs^4 (from Stefan-Boltzmann law). Now put a gas in the atmosphere up higher at lower pressures (Ps > Px) where the gas is transparent to solar radiation, but interacts with infrared as to turn each portion of the atmosphere it is mixed with into a blackbody (a greenhouse gas). Since anything else other than these greenhouse gases (ex. nitrogen, oxygen, argon) are transparent to infrared you can't measure the importance to be begin with as a function of quantity or mass in the atmosphere alone.

Now suppose you slice up the atmosphere into so many pieces as to make each slice isothermal. Each layer with a pressure greater than Px radiates like a blackbody at its temperature (with the energy flux emitted across all wavelengths proportional to the fourth power of the temperature). However, it is only the top layer which determines the radiation loss to space, and hence the heat balance of the planet. This is one reason why water vapor doesn't overwhelm CO2 as discussed at because it gets drier as you go up to lower pressures in the colder part of the atmosphere. The radiation from all the other ones is absorbed before it reaches the topmost layer, so the OLR is σT(Px)^4. As we put in more greenhouse gases, we increase the altitude of the effective radiating level, but clearly we can't make the upper layers a blackbody (understand also that the tropopause has increased in height {e.g. Santer et al 2003} consistent with the warming atmosphere). This happens when the lower layers become opaque to infrared (which is where you are only looking at one layer, but even still, we aren't near that point). If you go to the right place on the wings, quite a lot of the additional absorption is happening low down. The IR heating change is pretty uniformly distributed. Moreover, the whole troposphere is well mixed in heat, and is more or less constrained by convection to stay near the moist adiabat. In that sense, the vertical structure is largely fixed by convection, and the heating only sets the intercept (e.g.the lower trop temperature.)

So when you see a simplified version of the greenhouse effect on the internet (looking like solar radiation in, infrared out, gases absorb some infrared and re-radiate some downward) you should add to it: absorbed solar radiation determines the blackbody radiating temperature Tx. This is not the surface temperature, but the temperature at altitude Px, and Px is determined by the greenhouse gas concentration (where more greenhouse gases decreases Px). As you put in more greenhouse gases, it is more like a pinball effect where re-radiation goes downwards, upwards, collides with other molecules, etc but as you warm you increase the altitude of release to space increases, so even if you get saturated down below you will continue to warm (hence the non single slab atmospheric model).

In fact, if you look at the graphs on part 2 you'll realize there is still extra areas to absorb at thousands of times pre-industrial CO2 levels, past the 22 µm or 11 µm wavelengths. In fact, you'd have to go beyond what is in the HITRAN database, but even a place like Venus is not truly saturated, and we will continue to warm (especially down at the 1 bar pressure where we're at and at earth-like gravity) as we put in more greenhouse gases. Also, don't forget that the Earth’s temperature has not yet risen enough to restore the energy balance as you have a lag time required to warm up the oceans and melt ice to equilibriate with conditions aloft (you can almost say we're in 1980 in terms of what the oceans are doing) so even if everything stops today we will continue to warm and glaciers continue to melt as we equilibriate to new conditions which will take some decades. Obviously if we don't stop, this keeps continuing. We know there is about 1 W/m^2 of imbalance with more solar radiation being absorbed and heat going in the ocean (inconsistent with interal variability but greenhouse gases) (see Hansen et al 2005) so we still have at least 0.6 degrees C "in the wings" if everything stopped today, and we'll get about 3 C per 2x CO2 which is significant. -- Chris

Hello blacktip hunter, et al.

The reply looks good but there is no mention of the CO2 energy levels and how collision between air molecules (N2,O2,etc.) affects said energy levels. The CO2 molecule will not absorb the same frequency as it emits unless the base energy level is present through collision or the decay time from the base level to ground state is long enough. Pressure would play a big part in the CO2 molecules ability to act as a green-house gas.