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Discussion > GHG Theory step by step

Radical rodent

I suspect that you are thinking of a non-GHG Earth as a normal Earth from which the CO2 and water vapour were magically removed one second earlier. I am thinking of what that planet would be like when everything settled down.

I removed oxygen because I had to remove water.

Water vapour is a greenhouse gas and so an Earth without greenhouse gases is an Earth without water.

Water is essential for life so a planet without water is a planet without life.

Only life produces atmospheric oxygen, so a planet without life is a planet without oxygen.

If you assume that the remaining gas is mostly nitrogen then the pressure will be 11.6lbs/inch^2 or 800 mb.
The current values are 14.7lb/inch^2 or 1013mb.

Jul 30, 2017 at 2:21 PM | Unregistered CommenterEntropic man

EM. Why not compare like with like? Why not replace the radiative gases with nitrogen, more or less keeping the atmospheric pressure regime as close as possible to the real Earth's atmosphere? This to me would be a more valid comparison.

Jul 30, 2017 at 2:51 PM | Unregistered CommenterSupertroll

Radical rodent

Point conceded. My decrepit mind read the pressure scale as bars instead of millibars. That does not mean that I accept Huffman's hypothesis. You complain that nobody has refuted Huffman. In fact, as soon as any competent physicist realises that Huffman violates the 2nd law, that is an automatic refutation.

Elsewhere one of the engineers drew an analogy between surface temperatures on Earth and traffic through a telephone exchange. Second by second people were continually starting and ending calls, while the average, the number of calls per unit time, remained constant.

The Earth is similar. Each square metre may absorb or emit different amounts of energy second by second, but the overall energy content of the system remains stable. Do not mistake dynamic stability for static stability. There is endless small scale jitter, but the overall values may remain constant over long periods.

Over time changes in insolation , albedo and OLR may cause long term trends in average temperature, superimposed on top of the jitter.. tThis is normal and does not refute climate science.

Jul 30, 2017 at 2:56 PM | Unregistered CommenterEntropic man

Supertroll

Replacing oxygen with extra nitrogen would be an option.

I am intrigued by the different ways different people conceive of a GHG free Earth. I was a great fan of SF authors like Hal Clements who were able to conceive a world and then follow through the logical consequences.. I tend to do the same.

A classic example was " Mission of gravity", which took place on a heavy, rapidly spinning planet which ended up shaped like a discus. Surface gravity was over 30000g at the poles and and 3g at the Equator. A local explorer travelled between them and much of the story revolved around the changes in local conditions along the way.

Jul 30, 2017 at 3:14 PM | Unregistered CommenterEntropic man

EM I have fond memories of reading "A Mission of Gravity" Might I recommend Joshua Dalzelle's "Warship" (don't bother with the other two books of the trilogy). It is the only book I've read that honours celestial mechanics and real time in a space battle scenario within a solar system. Hope you enjoy.

With regards to comparing like with like, it is common practice when examining the effect of one component to try to keep all other variables as similar as one can. You should know this, it's basic experimental design.

Jul 30, 2017 at 5:19 PM | Unregistered CommenterSupertroll

Schrodinger's cat

I have no objection to the second division It was the first division that was invalid.

I got caught out the first time I looked at this topic years ago. I got confused because some sources quoted insolation as 1366W/m^2 and others as 342W/m^2

It turns out that there are two ways to a define insolation.

The first is the solar constant, the second is the amount of energy entering an average square metre at the top of the atmosphere.

Solar constant is the amount of power reach a 1m^2 flat panel perpendicular to the Sun's days at the distance of the Earth's orbit. That is about 1366W/m^2.

The other unit is watts/square metre. OLR leaves all of the planet's atmosphere, high or low latitudes dayside and nightside. To maintain continuity of units, energy budget calculations use watts/square metre averaged across the top of the atmosphere for both incoming and outgoing radiation.

Thus the solar constant is quoted as 1366W/sq.m, while average isolation is 1366/4 = 342W/sq m at the top of the atmosphere.

The insolation -albedo = OLR equation works whether you use total energy or watts/sq m, but not when you mix them.

Jul 30, 2017 at 5:51 PM | Unregistered CommenterEntropic man

Supertroll

It is also best practice to compare realities rather than fantasies. I have tried to get as close as possible to the way Earth would be if you genuinely removed all the greenhouse gases and then let it stabilise.

Jul 30, 2017 at 5:55 PM | Unregistered CommenterEntropic man

EM. I disagree, you haven't taken care to keep as many other parameters equivalent, especially when an alternative explanation depends upon atmospheric pressures which you seemingly deliberately alter.

Jul 30, 2017 at 6:33 PM | Unregistered CommenterSupertroll

Supertroll

Thank you . "Warship" is now on my Kindle.

I did not deliberately change the atmospheric pressure. I started with the premise of a planet without greenhouse gases and worked out what it would look like.

My desert is one option. The other is to keep the water, which then freezes to give you a snowball Earth. Neither is likely to have much photosynthesis, or much oxygen.

Perhaps you could describe what your GHG free planet would be like and explain why.

Jul 30, 2017 at 7:35 PM | Unregistered CommenterEntropic man

Supertroll

If you want to keep the water, the albedo of a snowball Earth would be more than 0.5.

The energy input would be less than 170W/sq. m and the temperature less than 235K.

That is 20K colder than my desert planet and the difference from the actual Earth up to 288-235=53K.

Jul 30, 2017 at 8:53 PM | Unregistered CommenterEntropic man

EM, I have explained many times that you can't take 255K (or whatever) from 288K to get the net effect of GHG. It's liking taking apples from oranges and measuring the result in bananas. The arithmetical average will only be comparable with the S-B number for an ideal planet. In any other case the actual radiation of the planet will be the same as incoming but the temperature will be less. The average watts/sqm are the same but given an uneven temperature distribution the measured average temp is not.

Jul 31, 2017 at 8:34 AM | Unregistered Commenterrhoda

Perhaps you could describe what your GHG free planet would be like and explain why.
Your pomposity encapsulated, in spades!

Can you not understand that this is a hypothetical planet? It does not have to exist in “real life;” it does not even have to comply with being able to exist in “real life.” The logic that the very nice Mr Kendal is applying is that you ONLY REMOVE THAT WHICH YOU WANT TO TEST – in this case, “greenhouse” gases. All other parameters remain, thus allowing you to examine the results, sans the factors under discussion. Unfortunately (in case you might have missed this point, along with so many others), this cannot actually be tested; it remains a hypothetical situation – what you might refer to as “a thought experiment.”

You also seem to be studiously avoiding Rhoda’s main point, in that the S-B calculations are for an ideal planet – i.e. a perfect sphere, with a perfectly flat, homogenous surface. Also, I suppose any atmosphere would be entirely composed of gas, with no particulates contained therein; this would also give the perfect wind-pattern that would exist by any convection incurred by heating. Now, even you have acknowledged that different topographies can give different results (Jul 28, 2017 at 10:23 PM), yet you also seem to pretend that… well… they don’t; they must all average out to the “perfect” value. Then, you also appear to ignore that these various topographies will also affect any wind-flow; are you so utterly unable to comprehend that there are many, many other factors involved with a planet’s climate than the S-B formula, and whether or not “greenhouse” gases are present?

Jul 31, 2017 at 12:11 PM | Registered CommenterRadical Rodent

Jul 31, 2017 at 12:11 PM | Radical Rodent

EM is trying to prove the validity of Climate Science in computer models.

I think we can assume he has given up on Lapse Rates.

Jul 31, 2017 at 12:49 PM | Unregistered Commentergolf charlie

RR seems to have no trouble getting the point. Or noticing the studious avoidance.


Before the defenders of this error start to claim they never said it, here's an example from Columbia university:

http://eesc.columbia.edu/courses/ees/climate/lectures/radiation/

Te = [(1-Aa)So / 4σ] 1/4

We have added a subscript e to the temperature to emphasize that this would be the temperature at the surface of the planet if it had no atmosphere. It is referred to as the effective temperature of the planet. According to this calculation, the effective temperature of Earth is about 255 K (or -18 °C). With this temperature the Earth radiation will be centered on a wavelength of about 11 μm, well within the range of infrared (IR) radiation.

Because of the spectral properties of the Sun and Earth radiation we tend to refer to them as "shortwave" and "longwave" radiation, respectively.

The greenhouse effect.

The effective temperature of Earth is much lower than what we experience. Averaged over all seasons and the entire Earth, the surface temperature of our planet is about 288 K (or 15°C). This difference is in the effect of the heat absorbing components of our atmosphere. This effect is known as the greenhouse effect, referring to the farming practice of warming garden plots by covering them with a glass (or plastic) enclosure.


Rhoda again: This error has been in that document since 2000. Did nobody ever ask a question about the dubious approach here? Do 97% of climate scientists accept this method of obtaining the impossible 33C conclusion. As full of bolx as an Elephants scrotum and just as easy to spot.

Jul 31, 2017 at 5:11 PM | Unregistered Commenterrhoda

I think we can assume he has given up on Lapse Rates.
Jul 31, 2017 at 12:49 PM | Unregistered Commenter golf charlie


Earlier (Jul 25, 2017 at 12:52 PM) S's C provides a link to a hey-presto calculation for lapse rate in a non-radiative atmosphere. As it is mumbo jumbo because of its omissions it may be better to refer to the book it (selectively) quotes, which is a straightforward derivation of lapse rate in Earth's troposphere.

Here is a link showing the isothermal calculation and its inherent stability.

Kinetic Gas Theory for Gas in a Gravitational Field

Jul 31, 2017 at 7:08 PM | Unregistered Commenterssat

Rhoda

Please confirm that you understand the difference between the mode and the mean of a frequency distribution.

Aug 1, 2017 at 12:02 AM | Unregistered CommenterEntropic man

Radical rodent

We have satellites and space probes which can look at the planet from outside.

You can measure insolation, brightness and OLR for up to half the planet at one time from a single satellite. Given several satellites you can get complete coverage.

You do not need to measure the surface one square metre at a time when you can measure the whole surface from above.

Aug 1, 2017 at 12:16 AM | Unregistered CommenterEntropic man

Aug 1, 2017 at 12:16 AM | Entropic man

Planet Earth is real. Theoretical computer-modelled Climate Science is not.

If you and your consortium of consenting Climate Scientists still have to rely on failed computer models, after all this time and money, you have failed Science.

Please confirm you understand the difference between real climate data, and Real Climate Data.

Aug 1, 2017 at 3:09 AM | Unregistered Commentergolf charlie

Your frequency distribution mode and mean is an attempted diversion. So are your satelllites. IF you are comparing the outgoing radiation obtained by satellites, quote that figure, NOT a figure obtained by thermometers, guesswork and infilling.

If you have a comparison between the ideal S-B number and the satellite-derived average, let's see it. However, the more I think about it the more I see that temperature should play no part in it. Watts/sqm should be the unit. I believe you said that 240 is the figure radiated from TOA? But that itself is an average. Again, because of T^4, you can't just convert 240 w/m2 into a hypothetical temperature and apply the lapse rate.


The point of all this is not to present some alternative hypothesis, that's another red herring on your part. The object is to illustrate dodgy methods and castigate those who espouse them if the results are convenient.

Aug 1, 2017 at 9:46 AM | Unregistered Commenterrhoda

Dang it, Rhoda – you’re good! I think I shall leave it to you, from now on, with just one parting shot:

You can measure insolation, brightness and OLR for up to half the planet at one time from a single satellite. Given several satellites you can get complete coverage.
Wherein you are potentially introducing an error, as any single satellite will only be able to monitor slightly less than half the planet, whereas the insolation covers slightly more than half the planet. Now, what is the imbalance in your precious energy budget, Entropic man? (And, while we are on it, when has Earth’s energy budget ever been in equilibrium for any significant time? – a question that others may also be noticing you are avoiding answering.)

Aug 1, 2017 at 10:46 AM | Registered CommenterRadical Rodent

Schrodinger's cat, Radical rodent, Rhoda, golf charlie

Schroedinger's cat

Radical rodent, rhoda and golf charlie are descending into rudeness rather than discussing the science properly. This usually signals the end of the discussion. Perhaps as moderator you might encourage courtesy.

Radical rodent

Because the Sun is larger than the Earth, slightly more than half the surface is illuminated. When you calculate the angles you find that the extra area is a strip 0.05degrees wide. That is a 5km strip around the terminator with a total area of 200,000 square kilometres. This increases the area of the hemisphere, 254 million sq km, by 0.08%. Since the angle of incidence is less than 1 degree around the terminator the increase in radiation would be less that 0.01%.

From L1 Earth subtends 0.72 degrees. A satellite measuring brightness for albedo, or dayside OLR cannot see a strip of the daylight hemisphere 72km wide.The area of this strip is 2,900,000 sq km, so the area missed is 1.14%. Since the area missed is at a low angle of incidence, the outward radiation will be undermeasured by less than 0.1%

The ideal configuration for albedo and OLR measurement would be four satellites in Earth orbit at 5000 km altitude. When they form a tetrahedron they would cover the entire surface simultaneously.

Since the measurement error is so small, applying a small calculated. correction to the existing measurements is much cheaper, I doubt anyone would spend $100 million for an extra four satellites to gain a marginal improvement.

Rhoda

Since you already know about frequency distributions I can keep this short.

Let the radiation entering or leaving 1 sq m be x. Let the total surface area of the Earth in sq m be y.

Plot a frequency distribution for incoming radiation. Because almost half the surface would not be illuminated the distribution will be asymmetric with the mode( the most frequent value of x) at a lower value than the mean (sum x/n).

Similarly a frequency distribution for OLR will be asymmetric with lower values for the nightside. The highest value will be at the subsolar point where the full 1366W/sq m comes verticallydown. This wiill decrease with distance from the subsolar point, in proportion to the cosine(I think) of the angle of incidence to a minimum in areas just before dawn. Again the distribution will be asymmetric with the mode lower than the mean.

T^4 is irrelevant.

Incoming radiation will be sum x or mean * n or solar constant*πr^2.

For outgoing longwave radiation OLR will be sum x or mean*n.

From your comments, your opinion is that because the mode is less than the mean, actual OLR will be less than the amount predicted by the SB calculation.

That is mathematically unsound.

Aug 1, 2017 at 2:09 PM | Unregistered CommenterEntropic man

EM. "T^4 is irrelevant."
I await you being stomped upon. Even poor mathematically illiterate me can see what Rhoda is on about (kudos to her for explaining it so well, carefully and without any rudeness).

Aug 1, 2017 at 3:10 PM | Unregistered CommenterSupertroll

Entropic man: good. Thank you for answering my first point about insolation and observation of a sphere. Now, will you answer the question you do appear to be avoiding: when, throughout the history of the planet, has the Earth’s energy budget ever been balanced for any period other than transitory?

(I do try not to be rude; I prefer to consider it more like… abrupt.)

Aug 1, 2017 at 4:21 PM | Registered CommenterRadical Rodent

EM, do you stand behind the construction of average measured temp 288K minus S_B ideal temp 255K equals 33C contribution of GHG alone, or not?

Aug 1, 2017 at 4:30 PM | Unregistered Commenterrhoda

Rhoda, Supertroll

I understand what Rhoda is saying too, but it is poor physics. She has it backwards.

Remember the SB equation

P = eAsigma(T^4 - Tc^4)

This works both ways. You can measure the power P and calculate the temperature T. You can also measure the temperature and calculate the power.

Cause and effect runs both ways too. Consider an airless or non-GHG planet. Pump a given amount of energy into a particular square metre of dayside surface and It will warm until it settles at the temperature at which insolation - albedo = OLR. The temperature is not the cause, it is the effect.

Now let the Earth's rotation carry that same square metre into darkness. A square metre of nightside receives no radiation but radiates to space. Initially the temperature determines the amount of radiation. As more energy radiates away the temperature drops and the rate of radiation also drops. This continues until dawn, when the sq m starts to warm again.

Given a suitably silly amount of kit you could measure every square metre.

In summary, in reasonably stable conditions when you average over the whole planet energy coming in should equal energy going out.

Anything else would violate the 2nd law that energy cannot be created or destroyed.

The physics of thermal radiation from materials determines that P is proportional to T^4, Even if it were T or T^14 the underlying pattern would be similar. The input and output power summed for the planet as a whole remain in compliance with the 2nd law and cause the temperature to adjust accordingly.

Local horizontal energy transfers can cause local variations in temperature and power output but the SB equation still applies and energy is conserved. If, as rhoda claims, OLR is less than incoming energy without a temperature increase, then energy is mysteriously disappearing from the system in violation of the 2nd law, automatic disqualification for any hypothesis.

Radical rodent

I've tried before to answer your stability question, but each time it seems to bounce off. Perhaps we have different ideas about what constitutes stability. Sigh. One more time.

To a climate scientists a stable climate is one which remains at a constant temperature, rainfall etc over a period of more than 30 years. For example, the Holocene had a stable climate from 10,000 to 5000 years ago

This does not mean that every day of every year has identical conditions. Local variations in temperature due to wind, cloud cover, sun angle etc cause local changes in temperature and radiation.

Every low cloud increases albedo and decreases OLR. The incoming net energy change is slightly negative and the clouded region cools a bit. Every high cloud increases albedo and decreases OLR, but the incoming net energy change is slightly positive and the clouded region warms a bit. A particular year may have more sunshine than average and be warmer, or may be cooler and wetter. This internal variation is normal.even in a stable climate.

Climates change too. Between 20,000 and 10,000 years ago the global average temperature warmed by 5C as we transitioned from glacial to interglacial conditions.The cause? A shift in energy budget due to orbital changes.

Cause and effect is the key. Climate remains relatively stable as long as the energy budget remains stable. When the energy budget changes, so does the climate. You cannot have spontaneous changes in climate without a cause.

Aug 1, 2017 at 7:30 PM | Unregistered CommenterEntropic man