Guest Post by Willis Eschenbach
Once again, the crazy idea that downwelling longwave radiation (DLR, also called infra-red or IR, or “greenhouse radiation”) can’t heat the ocean has raised its ugly head on one of my threads.
Figure 1. The question in question.
There are lots of good arguments against the AGW consensus, but this one is just silly. Here are four entirely separate and distinct lines of reasoning showing that DLR does in fact heat the oceans.
Argument 1. People claim that because the DLR is absorbed in the first mm of water, it can’t heat the mass of the ocean. But the same is true of the land. DLR is absorbed in the first mm of rock or soil. Yet the same people who claim that DLR can’t heat the ocean (because it’s absorbed in the first mm) still believe that DLR can heat the land (despite the fact that it’s absorbed in the first mm).
And this is in spite of the fact that the ocean can circulate the heat downwards through turbulence, while there is no such circulation in the land … but still people claim the ocean can’t heat from DLR but the land can. Logical contradiction, no cookies.
Argument 2. If the DLR isn’t heating the water, where is it going? It can’t be heating the air, because the atmosphere has far too little thermal mass. If DLR were heating the air we’d all be on fire.
Nor can it be going to evaporation as many claim, because the numbers are way too large. Evaporation is known to be on the order of 70 w/m2, while average downwelling longwave radiation is more than four times that amount … and some of the evaporation is surely coming from the heating from the visible light.
So if the DLR is not heating the ocean, and we know that a maximum of less than a quarter of the energy of the DLR might be going into evaporation, and the DLR is not heating the air … then where is it going?
Rumor has it that energy can’t be created or destroyed, so where is the energy from the DLR going after it is absorbed by the ocean, and what is it heating?
Argument 3. The claim is often made that warming the top millimetre can’t affect the heat of the bulk ocean. But in addition to the wind-driven turbulence of the topmost layer mixing the DLR energy downwards into lower layers, heating the surface affects the entire upper bulk temperature of the ocean every night when the ocean is overturning. At night the top layer of the ocean naturally overturns, driven by the temperature differences between surface and deeper waters (see the diagrams here). DLR heating of the top mm of the ocean reduces those differences and thus delays the onset of that oceanic overturning by slowing the night-time cooling of the topmost layer, and it also slows the speed of the overturning once it is established. This reduces the heat flow from the body of the upper ocean, and leaves the entire mass warmer than it would have been had the DLR not slowed the overturning.
Argument 4. Without the heating from the DLR, there’s not enough heating to explain the current liquid state of the ocean. The DLR is about two-thirds of the total downwelling radiation (solar plus DLR). Given the known heat losses of the ocean, it would be an ice-cube if it weren’t being warmed by the DLR. We know the radiative losses of the ocean, which depend only on its temperature, and are about 390 w/m2. In addition there are losses of sensible heat (~ 30 w/m2) and evaporative losses (~ 70 w/m2). That’s a total loss of 390 + 30 + 70 = 490 w/m2.
But the average solar input to the surface is only about 170 watts/square metre.
So if the DLR isn’t heating the ocean, with heat gains of only the solar 170 w/m2 and losses of 390 w/m2 … then why isn’t the ocean an ice-cube?
Note that each of these arguments against the idea that DLR can’t warm the ocean stands on its own. None of them depends on any of the others to be valid. So if you still think DLR can’t warm the ocean, you have to refute not one, but all four of those arguments.
Look, folks, there’s lot’s of good, valid scientific objections against the AGW claims, but the idea that DLR can’t heat the ocean is nonsense. Go buy an infrared lamp, put it over a pan of water, and see what happens. It only hurts the general skeptical arguments when people believe and espouse impossible things …
w.
I am pleased to see that there are some who have more persistence than I do and who are still questioning the dogma being put forward by Willis. I would have liked to have carried on participating in this debate, however, given the number of replies on this article, my computer really slows down and will not permit me to cut and paste etc. In fact, I am having difficulty in scrolling up and down to see who is saying what and what issues have been addressed etc.
I found his recent responses less than impressive. Whilst it is a sign of desperation when left to put forward analogies, I found the analogy he posted in response to my points (opening the door on a warm room), to be very poor. This is particularly so, since I had explained to him how the top few microns, which are cooler than the ocean below, essentially act as a barrier protecting the main bulk of the ocean. One can have an open door on a building if one employs an air blanket to create a barrier.
In fact, he seems to fail to appreciate the significance of the observational evidence that the top few micron layer is cooler than the ocean below. In particularly, since it is cooler than the ocean below, if it is over turned, it actually results in a net cooling of the ocean below. There is therefore an argument that DWLWIR leads to a cooling of the oceans.
Of course, however, the top few micron layer is cool because of the evaporation which occurs from that layer. Irrespective of the contribution to this process by DWLWIR, there would be evaporation in any event and thus it would always be expected that the top few micron layer would be cooler than the ocean below,
Whilst I am unaware of any evidence on the subject, given what is taking place at the air/top of ocean boundary, I would not be surprised if there was in fact a ‘dance of photons’. Leaving that to one side, if the ocean is evaporating at this boundary layer, which we know that it is, it follows that there will always be a mist consisting of evaporated water above this layer. It might be because of temperature profiles, one can not visually see it, but obviously it must be present. It is after all, the first/initial stage of the water vapour that rises to form clouds.
It does appear that very slight progress has been made. It does appear that Willis now agrees that DLR does not warm the oceans, and his argument should therefore be founded on the contention that it slows down the cooling of the oceans. This, of course begs the questions what caused the oceans to be warm in the first place.
Of course, the crux of this debate is net energy flow. Does anyone consider that the classical physicists of the 19th century would have thought that the oceans would freeze had they not seen Trenberth’s energy budget? The classical equations do not involve the effects of so called greenhouse gases, nor back-radiation.
They would simply approach the position, on first principle, that a body at X deg C surrounded by air at Y deg C (where Y is less than X) wants to give up a certain amount of its energy to its surroundings. They would work out how much energy the warmer body wants to give up and then they would look at the processes whereby that energy can be given up (eg., conduction, evaporation, radiation etc and the appropriate combination of these processes).
I for one would love to see the results of an experiment on the cooling profiles of a slab of stone say at 20 deg C which is placed in a giant hermetically sealed and insulated warehouse with air initially set at 15 deg C but with CO2 at 50ppm, 100 ppm, 200ppm. 300ppm and 400 ppm. I would be very surprised if the cooling profiles (ie., rate of cooling) was significantly different (but I am open to be convinced).
Unlike the land, the oceans very much influence their own atmosphere. They control its temperature (witness the small diurnal fluctuation) and the humidity. Given this and the fact that water vapour is a far more potent ‘so called GHG’, it is difficult to see what real difference an increase in CO2 levels from say 280 ppm to 380 ppm would achieve. Any role played by CO2 being wholly dwarfed by the presence of water vapour. Of course, I know that Willis’ article was discussing DLR generally and not CO2 induced DLR specifically and some people have side tracked the issue given that the wider debate concerns the role of CO2 in the atmosphere.
I meant to add to my final paragraph:
“If I am right on that, if there has been any warming of the oceans during the last century, it would strongly suggest that this is due to a change in cloudiness, which has allowed more solar radiation to reach and thereby to be absorbed by the oceans.”
That is the fundamental significance of accepting that DWLWIR cannot warm the oceans and at most simply acts so as to reduce the rate of heat loss from the oceans. The additional warmth seen in the oceans must have been created by some other influencing factor. Thus it is important that the significance of Willis’ concession is not overlooked.
Spector says:
August 18, 2011 at 2:50 pm
RE: Myrrh: (August 18, 2011 at 2:11 am)
“‘Visible light is only PARTIALLY transmitted through water, a fact which is obvious if you ask why is is completely dark below a certain depth’
“Because energy from the Sun isn’t eternal. Because matter slows down light. Water is matter, the deeper you go the greater the pressure. When you switch off your table lamp, where does the light go?”
It appears that you are suggesting that photons after going so far through the water just get tired and wink themselves out of existence. Not quite–conservation of energy applies.
What happens when your car runs out of petrol?
Do planes use more or less or the same amount of fuel flying into the wind or flying in calm conditions?
Even though the water is transparent, the chance of photon making it through any given length is always less than 100 percent. Eventually that photon is going to be captured in the water or on the bottom. That will make the capturing molecule warmer by an amount proportional to the frequency of the photon. That ‘lucky’ molecule will then share the energy of its ‘catch’ with all its neighbors.
The bottom of the ocean is dark, light, that is, visible, doesn’t reach it. Water is transparent to visible, it doesn’t capture it.
The only exception to this will be those lucky photons that strike a reflecting surface and make it all the way back up out of the water. In deep water there is very little hope of this.
Ah, but that lucky photon could exist, it would then be reflected all the way out to where it would again be bounced around the sky by all the nitrogen and oxygen molecules and then oops it gets bounced right back into the ocean where it’s still in its lucky streak and gets reflected back out where it gets bounced around the sky again by all the molecules of oxygen and nitrogen and back into the ocean and so on ad infinitum. Oh gosh, just like carbon dioxide backradiation keeps bouncing it back to earth heating the Earth /not allowing the heat to escape making the Earth hotter every time and the more carbon dioxide we put into the air the faster this process will accelerate and we end with runaway global warming! AGWScience is right! You’ve converted me! The light from every fire that has ever been lit must be accumulating too. /s
Sorry, I didn’t mean to be so rude. I’m leaving it in with an explanation, this post, because one of my gripes is that AGWScience Fiction Inc produces these memes that don’t bear scrutiny in the light of real physics, by mixing properties and processes, by denying properties and processes, by giving experiments to do that ignore the real properties and processes, such as above, the hot air gun supposedly proving that radiant heat energy, thermal longwave infrared, can’t heat water because there’s no difference between convection and radiant energy in the heat transfer of AGWScience’s imaginary worlds where all properties and processes are interchangeable as long as they ‘sound’ scientific enough to catch the unwary..
[See – http://en.wikipedia.org/wiki/Heat_gun – “Some heat guns incorporate a built-in rest, so they can be activated and placed on a workbench, which frees the operator’s hand. Heat guns can have nozzles which deflect their air for various purposes, such as concentrating the heat on one area, or thawing a pipe without heating up the wall behind.
Most have a heating element based on electrical resistance but some produce heat by a gas flame. A fan increases and focuses air flow for convection heating.
Other devices used for similar purposes include focused infrared heaters.”
See – http://www.speedheater.us/ ]
Some of the memes are so well ingrained into the education system from a concerted effort to achieve this result in the last decades and taken as if real physics by constant repetition generally, that even scientists normally logical and rational in their own disciples take these fictions for granted because they have no reason to doubt them. So heavier than air molecules can stay up in the atmosphere for hundreds and even thousands of years accumulating and can cross oceans in a matter of hours by Brownian motion… As I’m finding here, even scientists on such a sceptical science blog can’t get their heads around far enough to break out of these memes. What I can’t understand is their unwillingness to check it out for themselves when I have given sufficient information from pukkha sources to show that there is a definite disjunct. I thought I’d cracked the problem with at least one incontrovertable example of this manipulation, in that I had the NASA pages to show that there was manipulation of the basic science.
Which is all that I have been trying to get across. That there is a concerted and deliberate perversion of real basic physics in the dark heart of this AGW scam.
Water is transparent to visible light, it is transmitted through unchanged, unabsorbed, it does not heat water.
It really is a travesty that Trenberth can’t find the missing heat… He’s taken the real heat from the Sun out of his equations.
As have you all. And since visible does not heat the oceans, you not only have to add back in the thermal infrared, you have to take out the visible.
I hope you can at least see the import of what I’m saying here, even if you can’t yet get your heads out of the AGWScience fiction memes.
The factor missing from this experiment is that the walls of said warehouse must be set to 3 K to accurately model the situation, since the earth is surrounded by space @ur momisugly 3k. (Actually, any temperature WELL below the 15 C would work.) The greenhouse effect works because the CO2 (and other GHGs and clouds for that matter) are much warmer than the background and hence radiate much better than the background.
How much of the 390w/m2 are claimed to warm the ocean here? Based on net observed out going DLWR it is ~48 w/m2 + ~30 w/m2 + ~70 w/m2 = 148 w/m2.
The sun 170w/m2 and DLWR 390w/m2 would leave 560w/m2 warming the ocean, so as it’s not burning us to death then it would be causing the oceans to boil instead. This is due to the input is much larger than the output when you claim an equal loss is equal warming, so you can’t have it both ways.
170w/m2 v 148 w/m2 would still leave to the ocean gaining heat, but removing errors could easily leave it balanced and still much more realistic than the barmy combined sun and DLWR claim of 560 w/m2.
560w/m2 would give enough energy to warm the planet to about 373k, which is 100.3c.
560w/m2 v 100w/m2 still nonsense, or if claiming 390w/m2 warm the ocean, then why not the 30w/m2 and 70w/m2 warm them too? This is just as barmy as the claim with only DLWR warms the land and ocean. This is almost applying the same thing, but not to such an extreme way. My conclusion of this is someone trying to move a energy loss into an energy gain and it is utter nonsense. The ocean would be boiling with little energy escaping the planet surface over many thousands of years. (373.3k)
Over 400 comments now and still no links to empirical evidence showing that backscattered IR radiation around the 15 micron frequency can warm or slow the cooling of oceans. I find It hard to believe that something so central to AGW theory has no supporting empirical data. This affects 71% of the Earth’s surface. Without empirical evidence, the null hypothesis that there is no “Missing heat’ in the oceans because it was never prevented from leaving still stands.
In all probability the surface area of the earth unaffected by backscattered 15 micron IR is greater than this. Plants that are partially cooled by transpiration should be included the list of real Earth surfaces and materials that do not pay attention to black body equations.
Anyhow, due to the hand-waving, analogising and total lack of empirical data on this thread I have been forced to buy two probe type digital thermometers. Fortunately I already have plenty of computer fans, transformers, poly styrene foam, aluminium foil, cling wrap and sea water. I will test this over the weekend.
“a loss is warming”
Sorry, on my last post it should read “a equal loss is equal warming”
Please edit my last post and delete this message.
Thankyou.
Tim
You have not thought your comment through.
I am well aware that space is 3K and accordingly, Earth wishes to radiate away some of its heat.
The temperature of the walls of the warehouse play no role in the experiment and would needlessly complicate matters if the air inside wished to give some of its heat to the walls, and the slab some of its heat to the air and the walls. We only want to look at the rate of heat flow from warm slab to air.
All we are interested in is examining the role of CO2 in air (at one atmosphere pressure) at various concentrations on the rate of cooling of an object which is marginally warmer than the air which surrounds the object (obviously, we would require a fully insulated floor so there is no heat loss to the floor). I have suggested a 5 deg C difference in temperature between slab and air, but may be should be looking at less.
To reflect the position over the oceans, perhaps we should in addition repeat the experiment but this time with air with higher levels of humidity to see whether in this scenario any signal from CO2 is dwarfed by the effects of the high humidity.
You may have noted from my last comments that I consider it likely that any effect caused by a change in CO2 from say 280ppm to 380ppm will be wholly dwarfed by the high water vapour contents over oceans such that if the oceans have warmed, it is not due to an increase in CO2 but must be due to some other factor, the prime candidate for which being changes in cloudiness which has allowed more solar radiation to reach the surface of the oceans thereby leading to a warming.
I think it would be instructive to consider three separate parts of the ocean: the TOP 1 mm, the MIDDLE layer from 1 mm to 100 m, and the BOTTOM layer from 100 m on down.
Note: all numbers below are averages and are approximations. I don;t intend to get caught up in those minor details ATM.
MIddle receives ~170 W/m^2 of solar energy. Since Middle is warmer than Bottom, there is basically no energy transfer by convection from Middle to Bottom. And since the temperature gradient is close to zero, there is very little conduction, either. Somehow, Middle needs to release ~ 170 W/m^2 upward to Top, or else Middle would get warmer and warmer.
As estimated in an earlier post in this thread, Middle can transfer this amount of energy by conduction to , as long as a gradient of 0.2 – 0.3 K is maintained across Top. This will keep MIddle in balance.
Of course, Top ALSO needs to keep an energy balance or it will warm. TOP is receiving 170 W/m^2 from MIddle. Top is also receiving ~ 330 W/m^2 of IR energy from GHGs and clouds. Fortunately, it is losing 80 W/m^2 via evaporation, and 30 W/m^2 to convection/conduction, and 390 W/m^2 via upward IR. Give or take a little rounding, we are balanced.
BUT suppose one day I start shining a little extra IR onto the ocean — perhaps some diffuse IR lasers . Top will suddenly be out of balance and start warming! There are a couple of easy solutions to this. A little warming of the surface will increase the evaporation and increase the IR output. Warming the surface by 0.2 C will increase the the IR emissions by a little over 1 W/m^2. A back-of-the-envelope estimate suggests evaporation would also increase by a little over 1 W/m^2.
Whatever the actual numbers are, it appears that only a few extra W/m^2 will erase the temperature gradient across Top. This will erase the 170 W/m^2 of conduction across Top! Middle will start accumulating 170 W/m^2! Of course, MIddle has a large thermal mass and 170 W/m^2 will only slowly change Middle. By the time Middle has warmed 0.2 C, the gradient will have been restored, and Middle will stop warming any further.
SUMMARY — A few extra W/m^2 will lead to a warming of a few tenths of a degree C of the oceans.
NOTE: Yes, these are rough estimates. Yes the details will be horrendous when you start worrying about night/day, latitude, seasons, etc Yes, there are feedbacks (positive and negative) that have been ignored. But overall, the ability of IR to warm the ocean seems inescapable.
richard verney says:
August 18, 2011 at 6:58 pm
You may have noted from my last comments that I consider it likely that any effect caused by a change in CO2 from say 280ppm to 380ppm will be wholly dwarfed by the high water vapour contents over oceans such that if the oceans have warmed, it is not due to an increase in CO2 but must be due to some other factor, the prime candidate for which being changes in cloudiness which has allowed more solar radiation to reach the surface of the oceans thereby leading to a warming.
===================
I think I asked this same question about 400 comments ago.
The H2O absorption bands never reach zero, even in controlled laboratory conditions, as far as I can tell from the graphs. So, out in the wild, with all kinds of Doppler shifting of the absorption wavelengths going on for 30,000 ppm of water vapor, what’s the contribution of the last 100 ppm of Beer’s Law, logarithmically reduced CO2, even if we charitably assume that this is all anthropogenic ??
Besides f*****g zero.
Sorry, Richard, but if you don’t recognize that the cold surroundings are essential to the experiment, then you don’t understand the greenhouse effect. If the wall and the atmosphere are ~ the same temperature, then the atmosphere will have essentially no effect. The greenhouse effect ONLY works if the surroundings are cooler than the gas. (in fact, of the walls of the room were warmer than 20 C, the CO2 would actually help keep the slab from warming up, rather than helping to keep it from cooling down!
Willis Eschenbach:
You are one of my favorite reads. You OWE me a response to my comment, or you are no longer one of my favorite reads, but just another arrogant poster.
Tim Folkerts says:
August 18, 2011 at 7:26 pm
Whatever the actual numbers are, it appears that only a few extra W/m^2 will erase the temperature gradient across Top. This will erase the 170 W/m^2 of conduction across Top! Middle will start accumulating 170 W/m^2! Of course, MIddle has a large thermal mass and 170 W/m^2 will only slowly change Middle.
Hi Tim, it’s an ingenious argument, but since the Sun also emits IR directly, and the gradient across the top 1mm isn’t erased daily, I think there are many factors other than IR maintaining it which are not so easily displaced by a change in the atmospheric level of a trace gas like co2 from 0.027% of the atmosphere to 0.039%.
Otherwise the world would be a very unstable place indeed.
I did some calcs a while ago which show that a ~2W/m2 solar forcing on the ocean would raise the temperature of the top 700m 0.15C in 10 years. This is in line with the reduction of tropical cloud empirically measured by ISCCP using weather satellites 1980-1998. It also fits the sea level rise caused by thermal expansion of the oceans measured by the satellite altimetry.The timing is right, the magnitude is right, and it’s the most parsimonious explanation for late C20th warming.
Willis,
Jae has asked the following question at least three times of you on this thread:
Jae @ur momisugly August 16, 2011 at 9:42 am
Seems a reasonable question to me Willis. Why don’t you respond?
Oh, and is backradiation/DLR generally higher in the tropics than in hot dry deserts due to water vapour being more plentiful in the tropics? If that is so, why are hot dry deserts typically very much hotter in the day than in the tropics? I remember jae asking this elsewhere long ago, and it seems to remain one of those great gobsmacking mysteries that few want to consider.
Whoops;
Further to my support just above for jae, might I add that the albedo for desert sand is quite high, commonly quoted at 0.4. Old snow has also been quoted at 0.4 and above, but the topic is confused at high latitudes partly because of low solar zenith angles resulting in increased reflection. (very much so on water, and an unwillingness for ice-melt-feedback alarmists to accept that reality).
tallbloke says: August 18, 2011 at 11:39 pm
>Hi Tim, it’s an ingenious argument, but since the Sun also emits IR directly,
But the sun emits different wavelengths of IR. See http://eesc.columbia.edu/courses/ees/slides/climate/absorption.gif for example.
>and the gradient across the top 1mm isn’t erased daily,
The IR from the sun (mostly 0.7- 3 um) penetrates much much better, so it is not stopped in the first few microns like thermal IR is. See http://www.btinternet.com/~martin.chaplin/images/watopt.gif
Thus solar IR doesn’t provide much energy to that top 1 mm. Solar IR would not be effective at heating the top fraction of a mm.
(And even if it was effective at heating the top, that would be part of what set up the current quasi-stable climate conditions. It is only the CHANGES that I am addressing.)
> I think there are many factors other than IR maintaining it which are not so easily
>displaced by a change in the atmospheric level of a trace gas like co2 from
>0.027% of the atmosphere to 0.039%.
Certainly there are many other factors involved. Those will certainly affect the MAGNITUDE of the effect I described. It will not change the SIGN of the effect, however, with some significant factor that I did not include that acts in an OPPOSITE way to increased IR..
The “trace gas” argument doesn’t fly with me, since there MANY things in nature at are very important at low concentrations. Changes in these small concentrations are perfectly capable of creating changes in the forcings. See Willis’ new post about the oddities of MODTRANS, for example, to see estimates about how changes in CO2 affect
Tallbloke also says:
This is interesting and certainly is worth further consideration. The 10 year time frame sounds reasonable (and some quick calculations confirm the magnitude). I don’t know enough about cloud cover to know how much it has changed, so I cannot really confirm nor refute this hypothesis at the moment.
(That is one challenge with climate change — there are so many factors that COULD be important. Sorting it all out takes a LOT of time and knowledge.)
Konrad says:
August 18, 2011 at 6:20 pm
“Over 400 comments now and still no links to empirical evidence showing that backscattered IR radiation around the 15 micron frequency can warm or slow the cooling of oceans. I find It hard to believe that something so central to AGW theory has no supporting empirical data. This affects 71% of the Earth’s surface. Without empirical evidence, the null hypothesis that there is no “Missing heat’ in the oceans because it was never prevented from leaving still stands.”
Amazing, innit? Next up on the hit parade is why the vaunted GCMs have never been run for an earth lacking an ocean. Ya know why? Because the earth would be as cold as the moon in very short order. It isn’t the greenhouses gases that raise the temperature of the planet 33C above blackbody temperature. It’s a liquid global ocean that does it. Non-condensing greenhouse gases serve as “kindling” to ignite the water cycle. They are important only when the global ocean is largely covered by ice.
The modus operandi of greenhouse gases is that they are transparent to short wave solar radiation and opaque to thermal radiation. This allows sunlight to heat the surface instantly and the absorbed energy, when reemitted as thermal radiation, has more tortuous escape path.
The exact same thing holds true for liquid water. Water is transparent to visible light so sunlight can penetrate instantly to some 100 meters depth until impurities in seawater eventually absorb it all. Because water is quite opaque to thermal radiation the absorbed solar energy has a more tortuous path of escape. Specifically the solar-warmed water at depth must be mechanically transported to a surface skin just a few microns thick where the energy can escape to the atmosphere by conduction, radiation, and evaporation. Conduction accounts for little (5%), radiation accounts for a small fraction (25%) and evaporation accounts for most of it (70%).
So we have two important take-home lessons. GHG’s have little effect over the ocean and the ocean itself (not GHGs above it) accounts for most of the greenhouse warming of the planet.
Once you accept these facts all observations fall neatly in place. Yes, Virginia there is some greenhouse warming of the planet by GHGs but the effect is small and it only happens over land. The ocean is running the show, not the atmosphere. The most important role, by far, the atmsphere plays is simply providing enough surface pressure so that liquid water can exist over a temperature range of 0-100C which makes a liquid global ocean possible in the first place. The atmosphere could be pure nitrogen at 14psi and the earth’s climate would be essentially the same so long as the ocean remained liquid. The caveat is that the earth doesn’t receive quite enough energy from the sun to keep the ocean liquid so without some modest amount of non-condensing greenhouse gases you’d get a runaway freeze (which has happened before) that would last until enough greenhouse gases and albedo-lowering volcanic ash accumulated to begin a melt. Then you’d get a runaway melt until the ocean was liquid again.
Tim
Let me get this straight.
You are saying that CO2 does not in itself have the ability to absorb some of the photons being radiated by the slab and then to re-radiate these in all directions such that some of the re-radiated photons are sent back towards the slab either thereby heating the slab, or alternatively slowing down its cooling? Is that your case? Please revert on clear terms on that point.
Are you saying that where the air is at the same temperature as the surface below, there is no greenhouse effect? Again, please be clear in your response.
If so, if the air above the oceans is the same temperature as the ocean itself (which is commonly the position for the first 50 or 100 or few hundred feet) are you saying that there is no greenhouse effect in the first 50 feet and/or 100 feet and/or few hundred feet?
At what temperature interface does the greenhouse effect suddenly come into existence? Why was it not existing before this, and why and what precisely brought it into existence?
If it depends upon having an interface with colder air above it, to what extent will convection from below overcome in whole or in part the effect of the GHG warming/insulation?
I am quite happy for there to be a further variation in the experiment with the walls of the warehouse cooler than the air inside. In this scenario both the slab and the air will cool and may be a source of uncertainty/error since the temperature of the walls will have to be accurately controlled so that it is the same with all variations of CO2 concentrations. When we are looking for a small change in the profile of cooling iof the slab, it would be unfortunate if slight variations in the control temperature of the walls may mask the results being obtained. In my opinion that will needlessly confuse issues since additionally we will then being having significant convectional forces coming into play.
I look forward to hearing from you.
Tim Folkerts says:
August 19, 2011 at 3:10 am
Certainly there are many other factors involved. Those will certainly affect the MAGNITUDE of the effect I described. It will not change the SIGN of the effect, however, with[out] some significant factor that I did not include that acts in an OPPOSITE way to increased IR..
Is there any empirical evidence that the net balance has changed? If we suppose the increase in co2 has increased the DLR by 1.7W/m^2 in the last 100 years, then isn’t that offset largely by the greater upwelling LR coming from a warmer ocean surface? The average SST is thought to be around 17C or so. So how much more LR will that be emitting compared to a surface at 16.3C?
@Willis
“What seems to have escaped you is that this setup, cooler water on top of warmer water, is inherently unstable because the cooler water is denser than the warmer, and it wants to sink, and does so. The cooler surface is kept in existence by water moving to the surface, cooling, sinking a mm or so, rewarming, rising to the surface, cooling, sinking a mm or so, and so on.”
What seems to have either escaped you, or you ignored because I already pointed it out to you, is that viscosity is the dominant force in a surface layer only microns deep. It won’t sink if it’s cooler because viscosity holds it on surface. What actually happens is that this exceedingly thin surface layer evaporates continually exposing the surface below it. Think of DLWR as an ablative process like sand blasting or the heat shield on the space shuttle.
@Willis
“Tallbloke, that’s a lovely theory. Evaporated water molecules form an “invisible mist” above the surface. I’ve never heard of an “invisible mist” above the surface of the ocean … so surely you have some photos or some observations of this “invisible mist”, or at least a claim that someone has actually detected or measured the “invisible mist” …”
First rule of holes, Willis. When you’ve dug yourself into one, stop digging. Now we have this preposterous utterance of demanding pictures of something that’s invisible. Be a sport an take a picture of the oxygen in the air for me, Willis.
Water vapor is as invisible as oxygen. When you see steam, or fog, what you are seeing is water droplets not water vapor. Your deep ignorance is showing. Again. Stop digging.
Tim
You suggest that the atmosphere because it is much warmer than background space radiates much better. I agree insomuch as background space radiates photons at 3K whereas the atmosphere may be radiating photons at ~250 to 260K.
If I vary my experiment so that I have one slab at say 25deg C and another slab vertically above it at say 10deg C and in between the two I have air. Does the rate of cooling of the warmer slab depend upon the amount of CO2 in the air which separates the two slabs?
If so, why don’t the classical equations detail that, and state that the rate of cooling is dependent upon whether the air has 280ppm of CO2 (which was supposedly the case when the classical equations were formed) or 380ppm of CO2. Indeed, why do modern physic text books not state that the classical equations are no longer valid since the concentration of CO2 in air has increased and this therefore reduces the rate of heat flow from the warmer slab to the cooler slab?
I look forward to your explanations.
Tim Folkerts says:
August 18, 2011 at 10:39 am
“And here is an interesting conjecture. Suppose that DLR increases. This would deposit more energy in skin layer of the ocean, raising the temperature slightly. One effect would be to increase the evaporation rate (warm water evaporates faster), which would moderate the amount the surface temperature increases. A second effect would be to decrease the thermal gradient and hence decrease the thermal conduction up from the lower parts of the ocean. And of course, anything that limits the flow of energy from the ocean will necessarily increase the temperature of the ocean.
The logical conclusion from this conjecture — the more DLR, the warmer the oceans will get.”
It isn’t interesting, it’s wrong. As the water in the top few microns evaporates it exposes a new layer beneath it. It’s ablative. The water beneath is not shielded or insulated by the surface skin because the surface skin is constantly leaving he surface as a vapor exposing new skin a little further down. Sort like sanding a piece of wood. It’s an ablative process.
It’s extremely effective. So effective that 70% of the heat of the ocean escapes via this route while only 5% escapes via conduction and 25% via radiation. It’s a different story over dry land because rocks don’t don’t start evaporating until they reach a temperature of thousands and thousands of degrees.
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I note that some commentators have criticised the argument based upon CO2 being a trace gas. I endorse those criticisms.
The mere fact that CO2 may be nothing more than a trace gas does not in itself prevent it from playing a significant role in events such that where there are changes to the concentration of that trace gas, these changes could lead to significant effect. I for one wish that sceptics would not employ the trace gas argument. It is not scientific.
That said, I have for many years been saying that AGW does not work over the oceans: that changes in CO2 concentrations cannot explain the warming of the oceans. My main reasons for this are:
1. Due to the wavelength of DWLWIR, it cannot penetrate the oceans. It is absorbed in the first few microns where if it does anything at all, it merely increases the rate of evaporation which in turn leads to a cooling of the top few micron layer.
2. If the oceans over turns the top few micron layer, this would lead to a cooling of the oceans, not a warming.
3. The oceans are heated solely by solar radiation and it is the amount of solar radiation received which determines whether the oceans heat up.
4. Unlike land, the oceans very much control the atmosphere above them. They control its temperature thus why there is little diurnal range. Further, they control its humidity/water vapour composition. This is a factor of the warming received by the oceans from the input of solar radiation.
5. CO2 is not the dominant GHG. Water vapour is far more significant and given the very high concentration of water vapour over the oceans, AND the ratio between it and CO2, relatively modest changes in CO2 concentrations (up from 280 ppm to 380 ppm) are unlikely to have had much impact on the DWLWIR characteristics which may be in play over oceans. This is subtly different from the trace gas point. It relies upon the ratio between dominant water vapour and less dominant CO2 being overwhelmingly in favour of the dominant water vapour such that the effects of a change in the concentration of the less dominant CO2 are not significant enough to add sufficiently to the effects brought about by the dominant water vapour.
Once one accepts that DWLWIR does not heat the oceans (which Willis now appears to accept) and can at most merely slow down the cooling, if the changes in concentration of CO2 are not sufficient to add anything of consequence to the effects brought about by the dominant water vapour, the warming of the oceans cannot be explained by changes in CO2 concentrations and must be due to other causes. The most likely one of which is changes in cloudiness.
In other words, warming of the oceans is very probably due to natural variation. If the oceans warm, so too does the land and hence most of any warming seen over land is also predominantly accounted for by the natural induced warming of the oceans. I do however accept that changes in CO2 levels may have had some (in my view relatively modest, if any at all) effect on land temperatures, and that other manmade actions such as changes in land use and urbanisation may also have had some effect. However, given the ratio between the heat capacity of the ocean and that of the atmosphere over land, the oceans will always dominate and we are ‘pissing in the wind’ if we think that we can do anything of any significance to control the temperature over land by reducing CO2 emissions. (Please excuse my language) .