Guest Post by Willis Eschenbach
OK, a quick pop quiz. The average temperature of the planet is about 14°C (57°F). If the earth had no atmosphere, and if it were a blackbody at the same distance from the sun, how much cooler would it be than at present?
a) 33°C (59°F) cooler
b) 20°C (36°F) cooler
c) 8° C (15°F) cooler
The answer may come as a surprise. If the earth were a blackbody at its present distance from the sun, it would be only 8°C cooler than it is now. That is to say, the net gain from our entire complete system, including clouds, surface albedo, aerosols, evaporation losses, and all the rest, is only 8°C above blackbody no-atmosphere conditions.
Why is the temperature rise so small? Here’s a diagram of what is happening.
Figure 1. Global energy budget, adapted and expanded from Kiehl/Trenberth . Values are in Watts per square metre (W/m2). Note the top of atmosphere (TOA) emission of 147 W/m2. Tropopause is the altitude where temperature stops decreasing with altitude.
As you can see, the temperature doesn’t rise much because there are a variety of losses in the complete system. Some of the incoming solar radiation is absorbed by the atmosphere. Some is radiated into space through the “atmospheric window”. Some is lost through latent heat (evaporation/transpiration), and some is lost as sensible heat (conduction/convection). Finally, some of this loss is due to the surface albedo.
The surface reflects about 29 W/m2 back into space. This means that the surface albedo is about 0.15 (15% of the solar radiation hitting the ground is reflected by the surface back to space). So let’s take that into account. If the earth had no atmosphere and had an average albedo like the present earth of 0.15, it would be about 20°C cooler than it is at present.
This means that the warming due to the complete atmospheric system (greenhouse gases, clouds, aerosols, latent and sensible heat losses, and all the rest) is about 20°C over no-atmosphere earth albedo conditions.
Why is this important? Because it allows us to determine the overall net climate sensitivity of the entire system. Climate sensitivity is defined by the UN IPCC as “the climate system response to sustained radiative forcing.” It is measured as the change in temperature from a given change in TOA atmospheric forcing.
As is shown in the diagram above, the TOA radiation is about 150W/m2. This 150 W/m2 TOA radiation is responsible for the 20°C warming. So the net climate sensitivity is 20°C/150W-m2, or a temperature rise 0.13°C per W/m2. If we assume the UN IPCC canonical value of 3.7 W/m2 for a doubling of CO2, this would mean that a doubling of CO2 would lead to a temperature rise of about half a degree.
The UN IPCC Fourth Assessment Report gives a much higher value for climate sensitivity. They say it is from 2°C to 4.5°C for a CO2 doubling, or from four to nine times higher than what we see in the real climate system. Why is their number so much higher? Inter alia, the reasons are:
1. The climate models assume that there is a large positive feedback as the earth warms. This feedback has never been demonstrated, only assumed.
2. The climate models underestimate the increase in evaporation with temperature.
3. The climate models do not include the effect of thunderstorms, which act to cool the earth in a host of ways .
4. The climate models overestimate the effect of CO2. This is because they are tuned to a historical temperature record which contains a large UHI (urban heat island) component. Since the historical temperature rise is overestimated, the effect of CO2 is overestimated as well.
5. The sensitivity of the climate models depend on the assumed value of the aerosol forcing. This is not measured, but assumed. As in point 4 above, the assumed size depends on the historical record, which is contaminated by UHI. See Kiehl for a full discussion.
6. Wind increases with differential temperature. Increasing wind increases evaporation, ocean albedo, conductive/convective loss, ocean surface area, total evaporative area, and airborne dust and aerosols, all of which cool the system. But thunderstorm winds are not included in any of the models, and many models ignore one or more of the effects of wind.
Note that the climate sensitivity figure of half a degree per W/m2 is an average. It is not the equilibrium sensitivity. The equilibrium sensitivity has to be lower, since losses increase faster than TOA radiation. This is because both parasitic losses and albedo are temperature dependent, and rise faster than the increase in temperature:
a) Evaporation increases roughly exponentially with temperature, and linearly with wind speed.
b) Tropical cumulus clouds increase rapidly with increasing temperature, cutting down the incoming radiation.
c) Tropical thunderstorms also increase rapidly with increasing temperature, cooling the earth.
d) Sensible heat losses increase with the surface temperature.
e) Radiation losses increases proportional to the fourth power of temperature. This means that each additional degree of warming requires more and more input energy to achieve. To warm the earth from 13°C to 14°C requires 20% more energy than to warm it from minus 6°C (the current temperature less 20°C) to minus 5°C.
This means that as the temperature rises, each additional W/m2 added to the system will result in a smaller and smaller temperature increase. As a result, the equilibrium value of the climate sensitivity (as defined by the IPCC) is certain to be smaller, and likely to be much smaller, than the half a degree per CO2 doubling as calculated above.
Hmmm.
Bill Parsons commented (third comment):
“Wiki Answer to: “What is the temperature on the moon?”
The average daytime temperature on the Moon is around 107°C (225°F), but can be as high as 123°C (253°F).
When an area rotates out of the sun, the “nighttime” temperature falls to an average of -153°C (-243°F).”
Now, note that the average daytime temperature on the moon is not that far from what is reached by the soil in a low-altitude desert on Earth. Even a greenhouse easily attains 170 F.
It is interesting that that even with the slow rotation of the moon, “nighttime” temperatures don’t go anywhere near 3 K (-270 C), which is the temp of space. Ergo, the moon stores a lot of heat “overnight.” Without the aid of any “greenhouse gases.” Or without any water. This heat is stored in rocks and dust.
“Moon-Day” length is 29 earth days (14.5 earth days in light; 14.5 earth days in darkness). http://www.solarviews.com/eng/moon.htm
As indicated above, there is a 260 degree change between the moon’s “night” and “daytime” average temperatures. Assuming a linear loss of heat (bad assumption, but I don’t know how to do the proper T^4 math), the moon loses 260/14.5 = 17.9 deg/earthday. Or only 17.9/24 = 0.75 deg/hr. Therefore, crudely, if the moon had only a 24 hour day like earth, its temperature would only vary something like 17.9 degrees. So, it might be 123 C during the day and 105 C at night. Without any greenhouse effect.
The temperature of the earth could easily be a function of heat storage and have nothing to do with “greenhouse gases,” except that they aid in thermalization.
??
mkelly
Sorry dude, almost forgot about you. You also understand physics.
“Tides also within the vocabulary of climate science give fractions of a Watt/m^2.”
You are thinking only of tides in terms of ocean movements. When the moon and the earth rotate around each other they both get deformed like a squash ball and the area of most deformity travels around the earth at 1000 miles per hour. This happens to the whole of planet earth, not just the oceans. Thus the planet warms, just like it has been discovered that Europa is warmer than it should be for a body with no obvious source of external heating and too small for internal fission.
Meanwhile, the earth is 4000Celsius at its core which is similar to the surface temperature of the sun, only its not 93million miles away.
“The link I found by googling, I had not saved my calculations.
Certainly over direct flues the heating will be important, but that is another story. Averaged over the area of the earth it is small.”
Flues on land pump heat into the air and most of that is lost into space. Flues under the sea do not lose their heat to space. The specific heat capacity of water if very high, so the ocean simply stores the heat, then convection ensures fresh colder water gets a chance of further heating. The flues can be over 1000Celsius.
By the way, at some points the earths crust is very thin, and at others huge magma chambers are very close to the surface. There is much more of this volcanic activity under the oceans than on land. The average heat flux is not important if you have an efficient heat exchange mechanism in an area of very high heat flux – which you do.
Willis,
I believe you need to explain lunar regolith temperatures a bit more.
The temperature of lunar regolith at the Apollo 15 site was measured at an almost constant -23C (day or night) at a depth of 50cm (1). Apollo 15 landed at 26 degrees latitude (2) so it is roughly equidistant from polar and equatorial extremes of solar irradiance. Internal heating is almost nil so the regolith temperature is almost solely reflective (pun intended) of the intensity of solar irradiance and surface albedo.
Lunar albedo averages 12% (3) which is lower than the figure you give for the earth of 15% so we should expect the regolith temperature at depth would be even cooler if the surface albedo was the same as the earth.
Could you please explain the large discrepancy between average temperatures actually measured on the earth’s airless moon and your theoretical prediction of the earth’s temperature sans atmosphere?
Disclosures: I believe the experimental evidence is overwhelmingly against anthropogenic global warming of any adverse significance and what actual AGW there is has a net beneficial effect which in combination with increased CO2 makes for longer growing seasons and higher crop yields. Sure, there are winners and losers on a slightly warmer earth as climate patterns change the winners far outnumber the losers. What is really deserving of alarm is a cooling earth – crops don’t grow well in ice and snow.
references:
(1) http://education.ksc.nasa.gov/esmdspacegrant/LunarRegolithExcavatorCourse/Chapter5.htm#OtherPhysicalProperties
(2) https://nasm.si.edu/collections/imagery/apollo/AS15/a15landsite.htm
(3) http://www.geo.lsa.umich.edu/~shaopeng/Huang08ASR.pdf
A more realistic view of the amount of warming produced by the atmosphere is closer to 70C – not the 20C claimed in this article. Temperatures in the atmosphere drop linearly from about 280K to 210K as we rise from sea level to 10km, and then remain constant at higher elevations.
http://mtp.jpl.nasa.gov/missions/cirex/results.html
This gives a lapse rate of 2.1C/1000ft.
I remember one summer day in Arizona where I was hiking on dark colored rock in a snowstorm at the top of Humphrey’s peak at 12,000 ft, and later in the day was in 105 F weather in Phoenix. Temperatures varied by about 40C between the two locations, mainly because of the amount of atmosphere above the ground surface at the two locations. Cloud cover also played a role. Planes flying overhead at 35,000 feet would have been in temperatures close to minus 70 F.
“I live by the sea. In the summer air temperatures can be for a month from 37C to 40C the water is below 25C.”
I assume you mean the summer high temperatures for a month can reach 37 to 40 C.
I live a few miles from the beach- near LA.
I used to live in British Columbia on Vancouver Island- there ocean water was well below 25 C- probably something like 10 C. One couldn’t really swim in the ocean [though my uncle and others did a lot of scuba diving in this water]- and there were some beaches where was warm enough- basically the water would warm up when the tide came in.
In Canada I lived right on the beach and few times did swim briefly in the ocean at low tide between the shore and the kelp bed- I could feel a sharp difference between the very top layer of water and the rest of the water. Of course having the very top part of the water warm didn’t change the fact that the water was too cold to swim in for any amount of time- unless you worn a wet suit [though I think dry suits were mostly used for scuba diving in this area].
Though swimming in lakes was a different matter- depending the lake but in the summer a lot of them were warm enough.
Though with most coastal water the wave action will mix the water temperature- I lived on the east coast of Vancouver Island and if it wasn’t stormy weather the Georgia Straits could be fairly calm water.
“At night it is the opposite, particularly in autumn, when the water may be a steady20C while the air drops to 12 and 14C.”
There is no doubt there is a difference between ocean temperature and land temperature. Most of Europe and the place I grew up is milder and warmer because of the influence of the Ocean temperatures. Or the place where live now is cooler then say 10 or 20 miles inland- because of the ocean’s influence. And it can get considerably warmer here when there are what’s called Santa Anna wind- a constant air flow lasting for days coming from a land area instead of normal pattern daily ebbing back and forth from ocean to land.
“Again I refer to the surface skin temperatures in
http://isccp.giss.nasa.gov/products/browsesurf1.html”
I went over there, but I don’t know what exactly you referring to. I selected annual and both surface skin and air temperature, but it doesn’t seem to tell exactly what temperature each of the color represent [obviously it’s in Kelvin- that’s not a problem- but they have 12 colors and 4 numbers- I suppose you can sort of get that the global average temperature per that map seemed to be somewhere around 289 K? [[16 C]] but it shows up on my computer as a small map and at pretty coarse scale.
Glenn Tamblyn (05:13:30) : edit
Numbers on this one are hard to come by. However, it is known that thunderstorms are what drive the circulation in the Hadley cells, that is to say the global circulation, so your claim that they are a third order effect is risible.
Bryan (03:25:22) : edit
This is far from having enough information to answer. What is your point?
Francisco (09:31:15) : I know of no experiment done under STP conditions (0 deg C at 1 atm) or standard conditions (59 deg F at 1 atm) that has demonstrated CO2 could increase the temperature of anything.
anna v (09:23:56) : Thank you. I got a chuckle from it. That goes along with my CO2 thermos bottle. We should be able to come up with all sorts of CO2 heat increasing items.
“Save electricity throw out your old electric blanket and purchase a new CO2 filled comforter. Depending on per cent of fill you can have up to 74 additional watts of heating power per square meter. With a fleece cover that is washable this blanket will be the one you want when winter chill sets in. Purchase now for $29.99 for one but if you order now get two for $45.00. State tax not included.”
There is big opportunity out there.
Brian W (00:44:44) wrote:
“As to the sensitivity. CO2 with a specific heat less than N2, O2 and even aluminum, poor absorption compared to air, fast emission and most importantly a concentration of .038% by volume contributes NO sensible (usable) heat to our atmosphere. A doubling of CO2 will not give even .1 degree increase. I wish people would stop fixating on CO2. So the models do overestimate sensitivity by a huge amount. The whole AGW/CO2 thing is a stinking scientific fraud. Period.”
Brian W, thank you, in my opinion this is the salient analysis with regards to CO2 in the atmosphere (I’ve raised it here before).
There is only one problem with it. It’s too simple and straight-forward: It ends the argument and obviates any reason for further study of the issue. All that is left to study is fixing an upper limit of CO2 animals can properly and healthily respirate over the long term (which in all likelyhood would be rather simple and not require public funding, the life-blood of “modern science”).
Even scientists on the sceptical side of the argument seemingly don’t want to acknowledge this undeniable physical reality because all their angles of disputation (and funding) become unnecessary.
Needless to say, AGW scientists don’t want to acknowledge this physical constraint, either, as it defeats their arguments in total — no passing “GO”, no collecting $200 (government funding).
Problem: Until, heavy-hitter sceptical scientists write papers outlining this physical reality, AGW scientist won’t bargain against themselves and raise the issue on their own accord.
I’ve stated this issue before here on previous posts, asking to be corrected if I’m wrong, so far no-takers (that I’m aware of).
And, as I’ve stated before, hair-splitting on this parts per million or that parts per million CO2 concentration, is conceding over half the scientific battle and is akin to arguments about the arrangement of deck chairs on the Titanic.
(Just where the AGW proponents want the “game” to be played.)
But that’s where we find most sceptical scientists — arguing about deck chairs on the Titanic.
And, frankly, beyond my suspicions about funding dollars, it’s perplexing.
An old lawyer joke: “One lawyer in the town starves, two lawyers do a thriving business.”
Sure, I maybe wrong — but I’m from Missouri, “show me”.
And, until it is explained why I’m wrong, I’ll keep banging the drum and encourage others to do the same.
Glenn Tamblyn (05:08:52) : edit
Good question, took me a while to dig up the references. You are 100% correct that it seems strange, but there it is. The UN IPCC TAR says (emphasis mine):
“Radiative forcing”, in turn, is defined by the IPCC as:
Put them together and you get change in temperature divided by change in downwelling TOA irradiance.
Willis Eschenbach
….This is far from having enough information to answer. What is your point?
Thanks for the reply.
The conditions add up to eliminating any direct to surface from Sun radiation.
That should then mean that any radiation being measured would be back radiation from the atmosphere.
I’m not looking for an accurate figure just a very rough estimate.
Ryan Stephenson (04:33:23) : edit
Estimates of the total amount of geothermal heat coming through the surface are on the order of 4.2 x 10^13 Watts. However, the surface of the earth is about 5.1 x 10^14 square metres.
This gives a flux of about .1 W/m2. Even if this estimate were out by an order of magnitude, it would still be two orders of magnitude smaller than the solar and “greenhouse” contributions … in other words, a third-order forcing.
44.2 terawatts = 4.4 * 10^13 watts
Earth’s surface = 5.1 * 10^14 square metres
Heat flux = ~ 0.1 W/m2
yusuke (06:30:01)
First, if you leave out the exclamation marks!! and the accusations of deception, you are more likely to gain traction.
Next, I am going the opposite direction, from big to small rather than from small to big. To use your example, if my body temp went down 2° after taking 10 tablets, we will likely not be far wrong if we say that two tablets will take it down on the order of 0.2°.
Ryan Stephenson (08:05:27)
You are confusing average geothermal heat with the amount of heat directly over some geothermal hot spot. Your claim makes as much sense as saying “The lava coming from Mauna Kea volcano is at 1200°F, so global geothermal heat flux averages must be wrong.”
anna v (06:53:24)
Anna, thanks for the interesting reference. Unfortunately, their “download data” doesn’t work for me. But by inspection of the graphics, over most of the planet there is very little difference between skin temperature and surface air temperature.
If you can download the gridded data from them, let me know how, and I’ll do the analysis. For now, given the graphics, I say that the difference will only be on the order of a degree or so.
mkelly (11:33:35) : I know of no experiment done under STP conditions (0 deg C at 1 atm) or standard conditions (59 deg F at 1 atm) that has demonstrated CO2 could increase the temperature of anything.
==================
For such a controversial matter as this, the lack of such experiments is appalling. Some may argue they are impossible, but I don’t think so. You don’t need to reproduce the entire atmosphere, or anything remotely resembling that, to get an idea of how doubling or tripling or quadrupling CO2 concentrations in an isolated, open-top column of sunlit (or man-lit) air inside a controlled environment, affects its temperature near the bottom. Or any number of variations along that kind of setup. It cannot be that hard. It seems to me that infinitely more complicated experiments are routinely carried out in other fields.
It also seems to me that if we cannot detect any clear effect on air temperature under such easily measurable conditions, then what on earth are we talking about when we presume that little fluctuations in a quantity called “global mean surface temperature” (which is measured in grotesquely primitive fashion and using impenetrable methods) are the result of significantly smaller increases in CO2 concentration than the ones I mentioned??? None of this makes any sense.
I imagine those kinds of experiments must have been attempted, and if they had yielded any clear results in the desired direction, they would be routinely mentioned by the climate establishment as the empirical anchor to its fantasies. But we don’t see any of that. Nor do we see any attempt to set up such experiments. I wonder why that is.
O/T but Ive just been watching a re-run of Jeremy Clarkson’s ‘Inventions that changed the world’. In the one about jet engines, he claims that for 3 days after 9/11 when there were no areoplanes in the sky, the earth warmed 1degree during the day and cooled one degree at night. Does this mean that areoplanes rather than cause global warming actually causes cooling ?
Leif Svalgaard (08:42:40)
Leif, boreholes are an abysmal proxy for temperature. See my post on this question here, and the comments as well, where I show further problems. In particular, see my comment here, where I show boreholes a few miles apart that show radically different temperature histories.
This tread is amazing as most interveants are spending so much time making some more or less warranted maths in order to make the so-called consensus model work, whereas this model a) appear flawed from a theretical point of view (Gerlich & T, Robitaille, ) b) is no longer ‘alone’ (Miszolczi, the russian school…), c) so many predictions according to the model are just not to be found in the true life; it’s sad to see so little time spent on the respective merits of Miskolczi or the Russian
Anothe interesting point for the near future is how the contributions of Gerlich & T, Robitaille, Miszolczi, the russian school, the Galactic Cosmic rays assumption (CERN’s CLOUD experience which should fascinate anybody seriously interested in doing physics through acual experiences) will be treated in the frame of IPCC’s AR5, as it’s no longer possible to just ignore all these alternatives to the IPCC’s affirmation that CO2 is responsible because volcanoes and the sun’s irradiance are not
As to Joel Shore announcement of a peer reviewed “comment on G&T” paper, will this be more successful that Smith tentative ? anyway is the paper already available through Arxiv ?
Re: Willis Eschenbach (Mar 18 12:57),
in http://isccp.giss.nasa.gov/products/browsefmt.html they describe the various data
and on the main page next to the download data button they have choice of format, so choosing ASCII one gets a table .
Willis Eschenbach (13:38:27) :
where I show boreholes a few miles apart that show radically different temperature histories.
I know, I know, just like temperatures…
But when you average over thousands of them, the statistics gets a bit better.
I do not know how valid the 30 percent reflectivity figure is — I would assume it would be measured from space as a long-term average of that fraction of the radiation from the Earth that had the same signature as direct solar radiation without regard for the source of that reflected energy. As such, I presume this is a measure of that fraction the incoming solar radiation that is returned directly to outer space and plays no role in determining the Earth’s climate.
Thus, after reflection, we have an average level of about 239 W/m2 that must be emitted after becoming involved with the thermodynamics of the Earth. Perhaps this could be further reduced by including energy that is captured and released by the upper atmosphere without affecting conditions on the ground. In any case, the Stefan-Boltzmann equation yields a temperature of 255 K or -18 C for this energy flow per unit area. As I see it, this is a reference temperature only — it does not imply what conditions might produce it.
In the presentation of Dr. Miskolczi’s new greenhouse theory, Dr. Zagoni says the difference between this reference temperature and the Earth’s average surface temperature (+15C) is called the Greenhouse Temperature G (33 degrees C.) As such, he appears to be using this as a measure of the current effective thermal resistance or R-factor of the atmosphere.
Dr. Miskolczi has developed a new theory that includes a maximum limit to the greenhouse effect. He is reported to have discovered that the original work on this theory used equations only applied to planets with infinitely thick atmospheres.