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.
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Willis Eschenbach says:
August 16, 2011 at 2:41 pm
This means that information has been thrown away to get to the “net flow” number, and I prefer not to throw away information when I don’t have to.
Let’s be super-generous to ourselves and have all the numbers on the table
Downwelling solar absorbed by the ocean ≈ 170 W/m2
Downwelling ‘back radiation’ ≈ 320 W/m^2
Total = 490 W/m^2
Ocean Heat Loss:
Radiation originating from energy very near surface of the ocean ~220 W/m^2
Radiation originating from solar energy in the next 4km depth of ocean ~170 W/m2
Sensible (convection) 30 W/m2
Latent (evaporation) 70 W/m2
Total = 490 W/m^2
Net radiative loss from ocean to atmosphere ~70W/m^2
Willis Eschenbach says:
August 15, 2011 at 2:04 pm
You are right. To be accurate, DLR means that the surface is warmer than if the DLR weren’t there. So you are technically correct, but in common parlance we don’t usually say “It slows the cooling so it ends up warmer than it would otherwise”. We just say “it warms it”.
No, you actually say “it HEATS it”. Which is where it seems most people are getting confused.
Something I have a problem with in any scientific debate is that more often that not, a person arguing a simple idea will use “common parlance” which is actually not as common as as the person assumes.
Stop for a second and think about what you wrote with the non-common parlance in that “it heats it” means that it will increase the temperature above what it currently is (not that is slows cooling but it actually makes it warmer).
If I did not know the common parlance you use, I could refute all of your arguments based on that simple fact alone. Which is what a lot of commenters are trying to do.
If you really want to educate people (instead of generating a mass of comments that simply misunderstand what you are saying), assume they dont know ANY common parlance and acutally say “it slows down the cooling”.
richard verney says:
“I accept that you can receive $170 and give your wife $165 she then gives you back $164 and you then give her back $163 and she then gives you back $162 etc etc …”
Richard, you missed my point, I think. I’m not talking about handing the same bills back and forth, whereby I could only give a maximum of $170 at a time. Suppose I already have $1,000 in my wallet and she has $2,000 in her purse. My boss pays me $170 and I add it to my wallet. I pay my wife $400 for cleaning the house. She pays me $230 for mowing the lawn. Then she goes out and spends $170. We can hand back and forth large sums of money independent of getting $170 per day of new money and spending $170. While the true income is only $170, that does not stop me from giving my wife more than that each day. At the end of the day we both have what we started with.
Similarly, even though one square meter of surface receives only 170 W/m^2 of “new energy” from the sun, that does prevent the surface from “giving away” 390 W/m^2 of IR energy. Even though the atmosphere only receives ~ 70 W/m^2 of “new energy” from the sun, that does not prevent the atmosphere from emitting 325 toward the ground and 200 toward outer space. Looking at the total energy balance shows that the atmosphere gains as much as it looses. The surface gains as much as it looses. Everything stays in balance.
tallbloke says:
August 16, 2011 at 2:56 pm
“Net radiative loss from ocean to atmosphere ~70W/m^2”
Unless that radiative loss is balanced by a gain in energy then the ocean temperature would be falling like a stone. Clearly it isn’t falling like a stone. What do you propose is the source and mechanism of balancing energy?
Sorry Tallbloke, but I’m calling BS on that net radiative loss. I believe it’s demonstrated there’s a net radiative gain which is balanced by a latent loss. For some reason I thought that’s what you had concluded as well.
Willis,
Firstly, my congratulations on a very sensible article. I have no substantial disagreement,
Just a comment on the nett flow argument. You’re right that it can be analysed either way. But nett flow does clarify something in the boundary layer. Think of the energy balance of a submicron surface layer where conduction is sufficient to keep the temperature fairly uniform. It radiates up, and receives DLR. The imbalance is what has to be made up by other modes of heat transfer. The “inadequacy” of this is the non-problem you began with.
But looking at nett flow, it isn’t even an issue of downward propagation of thermalized DLR. The IR flows are physically added (with sign) at that surface, and the nett IR flow is up. Any issue would be – how can the surface be kept warm enough to maintain nett upward radiation. The answer is of course, turbulent heat transfer from below (ultimately from absorbed insolation). And observation is that it does seem adequate.
kuhnkat says:
August 15, 2011 at 11:37 pm
I’m sorry to have to say this again, but the individual flows are the real, actual, measurable, observable flows. The net flow is a mathematical construct, useful, but without a real-world counterpart. In addition we throw away information to use them. Which inter alia is why most folks use individual flows, particularly in multi-body situations.
w.
Willis wonders “You say the ocean doesn’t warm from DLR … so what keeps it from freezing?”
Boltzmann only requires the ocean to radiate the energy and says nothing about where that energy must come from. As I said in one of my earlier posts, in my view the DLR is absorbed into the top 10um and at about the same rate its absorbed, its re-radiated upwards as part of this requirement. Some is used for evaporation, and there are other factors to be considered but that is the essential process.
At no time does the energy from the DLR make it to the bulk. The ocean isn’t warmed by the DLR, its only ever warmed by DSR. DLR helps keep it warm.
Its not just sematics. Its process. And understanding.
Actually, Stilgar, in thermodynamics “it heats it” is neither necessary nor sufficient to conclude that “it warms it”.
“heats” = “transfers net thermal energy due to a temperature difference”
“warms” = “raised the temperature of”
These are two different concepts.
* I can heat ice without warming it (eg by melting it at 0C)
* I can warm air without heating it (eg by compressing it with a pump)
With these more specific definitions, I think it is perfectly reasonable to say “DLR warms the oceans” since the temperature is higher than it would be without that IR radiation. On the other hand, it is NOT correct to say “DLR heats the oceans” since the DLR comes from a region of cooler temperature, and the net flow of thermal energy can never be from cooler to warmer.
The true “heating” comes from the sun. With no loss of energy from the earth (ie perfect stopping of radiation from the earth), the surface would be heated until it approached the temperature of the sun. With complete loss (ie blackboady radiation loss from the earth), the temperature would be well below 0 C. With some stopping of IR, the temperature is somewhere in between. The exact value depends on how much the IR is reduced. Stop more IR, and the surface warms; stop less IR and the surface cools.
steven mosher says:
August 16, 2011 at 9:33 am
“The point is that no amount of theory, physics, experiment, will convince some people because they do not want to be convinced. We have a word for that. It starts with D”
I wholly disagree with your statement. Many WUWT readers are from the engineering professions. A well designed and conducted experiment will indeed convince people. You have failed to acknowledge that study you linked to at RC does not provide adequate empirical data for the question being asked. “Can backscattered IR around the 15 micron frequency heat or slow the cooling of Earth’s oceans to any measurable degree?”
The experiment required is simple
-Enclosed controlled environment preferably cold
-Two tanks of sea water at a known temperature.
-Air sources at a known temperature, humidity and wind speed for both tanks.
-IR source emitting only between 10 and 20 microns with a spectral peak around 15 microns, above one tank only.
-A few accurate thermometers.
This thread now has over 250 comments and no one has pointed to such an empirical study. 100 billion spent on global warming research and no one has done this?
“Do you have any cheese at all?”, he asked, expecting the answer “No”…
“The 390 w per sqm is a factor of the 170 w per sqm received from the sun. It is created by the solar energy received by the earth. If the sun had never fired up, the 390 w per sq m would not exist. You cannot create something from nothing and whatever is downwelling from the atmosphere it cannot be more than we have received from the sun.”
Evidently the hockey team believes it create something from nothing whenever it’s convenient. They can make ice without water if need be.
Here’s my take. As far as the team goes these instantaneous energy transfers are pure unadulterated obfuscation. When you have two terms on either side of an equation that cancel out you cancel them out. It’s called simplification and is taught in high school mathematics I believe beginning in Algebra 1. If you fail to produce the simplest form of an equation you get dinged for it. Willis evidently has been out of high school too long to remember the basics.
But let’s presume for a moment that Willis could pass a 7th grade algebra test. That raises the question of why on earth he would insist on not following the rules. I don’t think his goal is obfuscation. I think it’s appeasement. Willis is insecure about his position in this debate up against guys with PhD’s so he’s saying to them “Look here, we’re all smart guys and I agree with most of what you say except for clouds”. Willis actually did say to me that he and Trenberth were both smart and understood this. Actually Trenberth is a whole lot smarter than Willis. But that’s not saying much. Trenberth isn’t particularly bright.
Dave Springer says:
“Sorry Tallbloke, but I’m calling BS on that net radiative loss. ”
I think that he specifically meant “net radiative loss IN THE THERMAL IR PART OF THE SPECTRUM”. There is a net overall radiative gain (when solar radiation is included), which allows for a net evaporative/convective transfer upward.
Dave Springer says:
August 16, 2011 at 3:33 pm (Edit)
tallbloke says:
August 16, 2011 at 2:56 pm
“Net radiative loss from ocean to atmosphere ~70W/m^2″
Unless that radiative loss is balanced by a gain in energy then the ocean temperature would be falling like a stone. Clearly it isn’t falling like a stone. What do you propose is the source and mechanism of balancing energy?
The incoming solar (170) less the latent and sensible loss (100) equals 70, which equals the net radiative loss.
These are Trenberth’s figures, which are wrong, but they are the one’s Willis likes to use, so for the sake of keeping the debate on an even keel so far as is possible, I’ll use them to demonstrate the falsity of Willis’ ice cube argument.
Willis Eschenbach says:
August 16, 2011 at 3:40 pm
I’m sorry to have to say this again, but the individual flows are the real, actual, measurable, observable flows. The net flow is a mathematical construct, useful, but without a real-world counterpart.
The real world counterpart to the net flow is the fact that the sum effect of the radiative flux is to cool the ocean by ~66-70W/m^2
NASA have stopped using the K-T energy budget cartoon on their website which shows the separate LW radiation components and replaced it with this one which only shows the net flow:
http://tallbloke.files.wordpress.com/2010/06/energy-budget-new.jpg
Why does “the team” pursue this obfuscatory complexification of the ocean heat budget one might ask.
The reason is simple. If you toss about all these big numbers about hundreds of watts of LWIR coming out the ocean and hundreds of watts of LWIR flowiing back into the ocean it obscures the fact that primary mechanism of energy loss by the ocean is latent heat, not radiative. The net radiative heat loss at the end of the day is 50Wm, conductive heat loss is 20Wm, latent heat loss weighing in at 140Wm. Energy into the ocean 200Wm which exactly balances out. This accurate correctly simplified equation leaves us arguing over a tiny, hypothetical imbalance on the order 2Wm more input than output. To add insult to injury no one can actually find any sign of the imbalance – it’s all just mathematical creation in a toy computer model with no empirical evidence that it actually exists in nature – hence the infamous “missing heat”.
This would be funny if there weren’t so many imbeciles that believe the output of toy computer models trump reality. It’s sad really and brings to mind something Richard Dawkins said (my modifications for context):
It is absolutely safe to say that, if you meet somebody who claims
notto believe inevolutionanthropogenic global warming, that person is ignorant, stupid or insane (or wicked, but I’d rather not consider that).— Richard Dawkins.
Dave Springer says:
Dave you seem to be a smart guy, but Willis has a real talent for explaining things, and I for one appreciate his articles very much. Why don’t you submit an article, and see what it’s like being on the receiving end of criticism?
You could have left your last papragraph @ur momisugly 3:53 pm out completely. It was petty and juvenile. How old are you, anyway?
tallbloke says:
August 16, 2011 at 4:14 pm
“NASA have stopped using the K-T energy budget cartoon on their website which shows the separate LW radiation components and replaced it with this one which only shows the net flow:
http://tallbloke.files.wordpress.com/2010/06/energy-budget-new.jpg”
Precious. What happened, did Hansen’s high school algebra teacher ring him up on the telly from the nursing home and tell him if he didn’t start following the rules she taught him she’d smack his hand with her ruler?
Pay attention Willis. No more need to appease your foils by agreeing with their errors. You have a new party line to parrot.
In nonscientific usage, the difference between warming and heating is a matter of degree. Warming is putting a blanket around yourself or standing near the fire. Heating is what you do to make boiling water. Perhaps warming==gentle heating.
Dave Springer says:
August 16, 2011 at 12:13 am (Edit)
… The craziest, ugliest, silliest, nonsensical impossible thing (you set the tone, Willis, not me) is that an ocean which receives a net input of 200Wm can emit more than that and sustain the loss indefinitely. Conservation of energy is a bitch that isn’t going to budge.
I’m not sure what you’re saying here. I raised four arguments against the idea that the DLR doesn’t warm the ocean.
That doesn’t seem like an answer to any of them.
I’m still waiting for responses that actually address the arguments. For example, we know that the ocean radiates somewhere around 400 w/m2 of Stefan-Boltzmann thermal radiation. You say it receives a net input of 200 w/m2.
I say it gets about 170 w/m2 from the sun, plus about 320 from DLR, for a net input of 490 w/m2. It loses about 390 by radiation, about 80 by evaporation (latent heat transfer) and about 20 w/m2 by conduction (sensible heat transfer). Total loss, about 490 w/m2. Total input, about 490 w/m2 … so it balances, it neither gains nor loses heat so after a hundred years it’s neither freezing nor boiling.
You say the 320 w/m2 DLR is an illusion … OK, so what keeps the ocean from freezing in your scheme?
Here’s the simplest possible model of the global energy budget. A greenhouse works because a shell has two sides, and so it radiates the same amount (in w/m2) upwards as it does downwards. Note that all of the levels are balanced—the amount of energy going in is equal to the amount of energy going out, probably I should post this up in the head post.
w.
Dave Springer says:
August 16, 2011 at 4:14 pm
The net radiative heat loss at the end of the day is 50Wm, conductive heat loss is 20Wm, latent heat loss weighing in at 140Wm. Energy into the ocean 200Wm which exactly balances out.
Dave, where are your figures from please?
Smokey says:
August 16, 2011 at 4:17 pm
“Dave Springer says:
Dave you seem to be a smart guy, but Willis has a real talent for explaining things, and I for one appreciate his articles very much. Why don’t you submit an article, and see what it’s like being on the receiving end of criticism?
You could have left your last papragraph @ur momisugly 3:53 pm out completely. It was petty and juvenile. How old are you, anyway?”
I’m 55 and I was writing articles on global warming begining in 2005 and I quit in 2009. Been on the receiving side plenty.
Quite frankly Willis needs the upper hand of being the author and me the commenter to make the playing field a bit more level. This whole damn article was a response to ME for suggesting in a different article of his that LWIR from greenhouse gases doesn’t effect the ocean to any significant degree. I don’t begrudge him the ability to respond to an obscure comment of mine with a headline, large print, pretty pictures, and words directed at me like silly, nonsense, impossible, and ugly. Poor little Willis needs all the advantage like that he can get and at the end of the day he still comes up lacking.
@tallbloke
Dave Springer says:
August 15, 2011 at 10:18 pm
http://www.atmos.umd.edu/~carton/pdfs/foltzetal03.pdf
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. C5, 3146, doi:10.1029/2002JC001584, 2003
Seasonal mixed layer heat budget of the tropical Atlantic Ocean
Gregory R. Foltz, Semyon A. Grodsky, and James A. Carton
Department of Meteorology, University of Maryland, College Park, Maryland, USA
Net surface heat flux is a combination of latent and
sensible heat loss, shortwave radiation absorption, and net
longwave emission. Sensible heat loss is insignificant (<10
W m2) due to small air-sea temperature differences, while
net emission of longwave radiation is a relatively constant
50 W m2 [da Silva et al., 1994].
Willis Eschenbach @ur momisugly August 16, 2011 at 2:12 pm
Willis, please try to understand that EMR (electromagnetic radiation), regardless of wavelength and power, is a different form of energy to HEAT. Put another way, the 400 w/m^2 that you visualise as leaving the surface even though measured in the same units is not rate of HEAT loss. Repeat, EMR is not HEAT.
In understanding science, things are getting desperate when resorting to analogies, but let us compare EMR with DC ELECTRICITY.
1) Electricity is not heat but can be converted to heat by passing it through a resistance, which you might visualise as being like EMR being absorbed in matter. (the photons are akin to electrons)
2) Consider two DC sources of different voltage connected in opposed series, think about what the combined PD is and compare it with opposing EMR’s. Note also that if the voltages or EMR’s are equal, nothing happens. This can be visualised in a typical elemental layer of air where most of the radiation is horizontally opposed.
Dave Springer says:
August 16, 2011 at 4:34 pm
http://www.atmos.umd.edu/~carton/pdfs/foltzetal03.pdf
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. C5, 3146, doi:10.1029/2002JC001584, 2003
Nice, thanks.
Bob_FJ says:
August 16, 2011 at 4:46 pm
In understanding science, things are getting desperate when resorting to analogies, but let us compare EMR with DC ELECTRICITY.
1) Electricity is not heat but can be converted to heat by passing it through a resistance, which you might visualise as being like EMR being absorbed in matter. (the photons are akin to electrons)
2) Consider two DC sources of different voltage connected in opposed series, think about what the combined PD is and compare it with opposing EMR’s. Note also that if the voltages or EMR’s are equal, nothing happens.
As analogies go, it’s a good one I think.
tallbloke says:
August 16, 2011 at 4:14 pm
You can still get the net longwave and shortwave from the NASA radiation buget project on this site for January and July.
Net SWR
http://www.physicalgeography.net/fundamentals/7i_1.html
http://www.physicalgeography.net/fundamentals/7i_2.html
Net LWR
http://www.physicalgeography.net/fundamentals/7i_3.html
http://www.physicalgeography.net/fundamentals/7i_4.html
Net Radiation
http://www.physicalgeography.net/fundamentals/7i_5.html
http://www.physicalgeography.net/fundamentals/7i_6.html