By Dr. Roger Pielke Sr.
Andy Lacis has posted two guest contributions on my weblog;
Guest Post “CO2: The Thermostat That Controls Earth’s Temperature” By Andy Lacis
Further Comment By Andy Lacis On CO2 As A Climate Thermostat
I very much appreciate this collegial interaction.
Today, I want to comment on his conclusions.
First, I agree with Andy’s conclusion that if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool. I also concur that CO2 is a first order climate forcing and is a non-condensing greenhouse gas forcing.
The more interesting question, however, is how this applies both to how the Earth’s climate system actually evolved, and how incremental increases in CO2 above what was present in pre-industral times alter the climate.
With respect to the early Earth atmosphere, CO2 was emitted from volcanic eruptions but so was water vapor. The two acted together to warm the climate. Indeed, this is one explanation proposed to explain the warm, wet period in the earlier atmosphere of Mars and Venus. While, the model experiment presented by Andy and colleagues is quite interesting, it does not reflect the real climate system.
The second issue is, of course, directly relevant to our future climate. As I posted in
we have examined the effect of incremental increases in CO2 (and water vapor) as described in detail in
Relative Roles of CO2 and Water Vapor in Radiative Forcing
Further Analysis Of Radiative Forcing By Norm Woods
In regards to the effect of an incremental effect on radiative flux of an increase in the atmospheric concentration of CO2, there is an informative figure at Watts Up With That in a post by David Archibald titled The Logarithmic Effect of Carbon Dioxide. The figure is from 2006 by Willis Eschenbach which was posted on Climate Audit.
What is of importance to our future climate is the added downwelling radiative fluxes as given by the green and black lines. The Lacis and colleagues study examined the effect of the radiative forcing from red line.
The issue with respect to our future climate is how will it be altered in response to these incremental increases, part of which (particularly in the humid parts of the world) overlaps with water vapor absorption).
In terms of how environmentally and societally important resources are altered, as I have often posted on (e.g. see), in terms of climate, this involves how droughts, floods, tropical cyclones, heat waves, etc are altered. This means the focus should be on alterations in regional ocean and atmospheric circulations, mesoscale weather patterns, and so forth rather than on trends in the global average surface temperatures. The addition of CO2 is one factor (both radiatively and biogeochemically) but is not the single ”control” of these climate metrics.
The equilibrium temperature of Earth is just one of these metrics, and, indeed is not adequate to explain how regional and local climate could change. In fact, even with respect to global warming and cooling, the use of ocean heat content is a much more robust way to diagnose these climate system heat changes than a global average surface temperature trend, as discussed most recently in
Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55.
Andy’s posts (and paper) do clearly show that
“ there is a clear demonstration that without the radiative forcing provided by the non-condensing GHGs, the terrestrial greenhouse effect collapses because there is no structural temperature support to restrain the current climate water vapor from condensing and precipitating.”
However, there needs to be a recognition that the human influence on the climate system, including global warming and cooling, involves much more than the non-condensing greenhouse gases, and that the role of natural climate forcings and variability remain incompletely understood. We have discussed this in our paper
Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell, W. Rossow, J. Schaake, J. Smith, S. Sorooshian, and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union.
I invite Andy to discuss where he agrees, and where he disagrees, with our conclusions and recommendations in the above paper.
Mike says: “. . . main problems posed by global warming on land. . .changes in rainfall patterns and possible sea level rise.”
Since recorded history began, there have been changes in rainfall patterns. Morever, other activities of humans would have more effect on rainfall patterns than ncreasing a gas from .038% of atmosphere to .046%. Consider deforestation, concrete and steel landscapes, and irrigation — just to get started.
The end of the LIA probably has meant that sea levels have risen 7 inches a century. With more CO2 emissions, that rise could conceivably increase to 9 inches. Any mitigation for 7 inches probably should be engineered for 9 inches while they are at it.
RichieP says:
November 12, 2010 at 6:12 am
I’m not sure whether this is on topic or off but I’m going to say it anyway. I have come to the point in all these discussions where I find myself thinking that the scientific and political worlds have simply become mad. I’ve just finished reading the CCS post below this one and simply had to stop because outright despair and rage kicked in at the lunacy and irrationality of the geo-engineering proposals involved […]
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Yes, our collective lunacy is depressing and hard to believe. I’ve always thought the CO2 sequestration projects could not possibly get underway, because surely the absurdity of it all would become clear. Apparently, no amount of nonsense, no matter how huge, can be ruled out from infiltrating our minds. Yes, sir, it is a dismal landscape.
Speaking of lunacy, a few years ago there were many serious reports about the viability of mining the Moon for helium-3 turning over and processing vast amounts of the Moon’s surface to collect the stuff (the concentration of helium-3 on the Moon’s surface is thought to be about 13 parts per billion) and ship it to Earth for fusion power, to save us from possible future scarcities of energy resources. There were many such reports, some of them quite enthusiastic. See for example this piece in Popular Mechanics. (It’s a short trip indeed from Lunacy to Lunar)
http://www.popularmechanics.com/science/space/1283056
[Excerpt]
LUNAR MINING
Samples collected in 1969 by Neil Armstrong during the first lunar landing showed that helium-3 concentrations in lunar soil are at least 13 parts per billion (ppb) by weight. Levels may range from 20 to 30 ppb in undisturbed soils. Quantities as small as 20 ppb may seem too trivial to consider. But at a projected value of $40,000 per ounce, 220 pounds of helium-3 would be worth about $141 million.
Because the concentration of helium-3 is extremely low, it would be necessary to process large amounts of rock and soil to isolate the material. Digging a patch of lunar surface roughly three-quarters of a square mile to a depth of about 9 ft. should yield about 220 pounds of helium-3–enough to power a city the size of Dallas or Detroit for a year.
Although considerable lunar soil would have to be processed, the mining costs would not be high by terrestrial standards.
RE: Tallbloke, jorgekafkazar, Barney
I have read that the atmosphere in Venus is so deep that at the surface it is equivalent to being in the deepest mine on Earth or below. Think Death Valley X 5. Of course it is hot !
At the altitude where the atmosphere is 1 earth atmosphere it is remarkably close to earth temperature. It is closer to the sun so I would be amazed if it weren’t just a little hotter.
So from this I think I’m becoming a Cretaceous Climate Convert: the believe that we must re-introduce all that carbon from dead dinosaurs back into the atmosphere to recover all those lost species that devolved so tragically.
I get dinosaurs and cheap energy all in one…
Let’s shoot for 2000 ppm, now not later!!!
Power in C^3: Cretaceous Carbon Climate.
If all atmospheric CO2 were to suddenly disappear reducing the CO2 partial gas pressure to 0 kpa, the oceans would boil as the CO2 came out of solution. It would be quickly replaced.
However, the ocean would maintain temperatures at the equator, long enough for the dead vegetation and animal life to be eaten by bacteria and fungi. This would result in huge additions of methane and additional CO2. Since methane is a more efficient IR scatterer… I, would therefore theorize, that the net result would be an increase in any so called GHE heating. IMHO as a thought experiment. GK
RichieP @ur momisugly 6:12 AM
It is an ‘Extraordinary Popular Delusion and Madness of the Crowd’. Suppose I told you that you have to keep reading the lunacy because you are the one bull in the herd who can stop it from going over the cliff. So persevere. Courage.
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“I wonder what’s a bigger disaster for humanity.
The warmists or the luke warmers.”
Lukewarmers are Warmists (Warmers). They just triangulate more to seem more reasonable. Just take Steven Mosher. He’s as much committed to selling Global Warming as anyone I can think of.
Andrew
Stephen Wilde says:
November 12, 2010 at 4:29 am
If all the CO2 were removed we would still have all our Nitrogen, Oxygen, trace gases and water vapour plus all our oceans and a continuing hydrological cycle all reacting to solar input just as they do now.
Would that not maintain atmospheric temperatures at much the same level ?
No because N2 and O2 don’t react to the solar input at all and with the drop in temperature the water vapor concentration goes down, the oceans freeze so the albedo increases etc.
‘With respect to the early Earth atmosphere, CO2 was emitted from volcanic eruptions but so was water vapor. The two acted together to warm the climate.’
With respect to you but me self fancy a dandy dumb a** question or two: Wasn’t earth’s temperature back in the good old days some zillion degrees or so, ok so maybe almost a zillion degrees less like a cool breeze of say +1500°. A few billion years later and poof we got oxygen producing critters taking up all the good spots in the ocean. Correct me i f I’m wrong here, but didn’t the atmosphere at the time of that hilarious party consist of a few more nasty molecules ‘an just water vapor and the ‘orrible carbon dioxide? How about methane, carbon monoxide, sulfur dioxide, sulfur acid, and the rest of the gang, were they on vacation?
Like I said might be dumd a** questions but it it seems to me that it would be a rather more rational to bet on earth as the primary driver for heat back then rather then from some puny feedback effect. :p
Vince Causey says:
November 12, 2010 at 7:18 am
Ehm, I’m just looking at that graph and it seems to be saying that the forcing due to CO2 is about 258 watts/metre squared. Isn’t that a bit large? I mean, the average global insolation is only 240 watts/metre squared. Something not quite right.
The measured LW forcing on the earth is ~300 W/m^2 even at the N Pole so that seems reasonable.
kramer says:
November 12, 2010 at 7:30 am
Mars has got about 9x as much CO2 in the atmosphere as Earth, it’s atmosphere is less dense than ours, there is very little water vapor in it’s atmosphere, and it gets around half the energy of the sun.
That said (and including any other factors I have missed), does the CO2 theory hold up on Mars? In other words, if we plugged in all the physical information of Mars into the equations for warming, would the result be close to the known temperature range that we see on Mars?
Yes, read RP Wayne’s book on planetary atmospheres.
If the CO2 level dropped to 160 ppm most plant life would cease. We were perilously close to that value for a while. Now it is recovering.
Wheat is a recent, 56-gene dicotlydon and is genetically capable of living at the low CO2 level that preceded its formation perhaps only 10,000 years ago. Wheat can be considered an evolutionary adaption to a new paradign of low CO2. 400 ppm CO2 is not normal on this planet.
If CO2 were removed from the atmosphere, it is not true all life would die. There are many life forms on earth that use sulphur compounds to survive. I have no idea how large they could become in a CO2-free atmosphere but the myriad forms would continue in CO2-free conditions just as they do now. There may be other energy paths that are sustainable.
This posting sent me looking for the thermostat. I found mostly scholarly articles for which I just don’t have the attention span. Here is one of interest. Dr. Masters says in part:
“If global warming has triggered the decrease in stratospheric water vapor seen since 2000, it could mean that the climate models have predicted too much global warming, since they don’t predict that such a negative feedback exists. On the other hand, if this is a natural cycle, we can expect the recent flattening in global temperatures to average out in the long run, with a return to steeper increases in temperature in the coming decades. ”
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1421
Water vapor is the dominant greenhouse gas, even at the tropopause cold point temperature of 191 ºK.
Simon says:
November 12, 2010 at 6:21 am
Correct me if I’m wrong, but I’m pretty sure they’ve discovered sulphur-based life forms around underwater volcanic vents.
They are carbon based bacteria that use H2S in their electron transport systems.
Should have clarified more. Instead of using a photon from the sun to activate the electron transport systems of photosynthesis they use H2S for the energy.
Dave Springer says:
November 12, 2010 at 3:49 am
Bryan says:
November 12, 2010 at 1:39 am
…….” if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool”……………………..
Everything remains the same except that CO2 does not absorb/radiate in the infra red.
What difference would that bring about?
A deeply frozen planet. The average temperature of the moon is -23C and its albedo is around 15%. A snowball earth would have an albedo of 85% and would thus be far colder than the moon. Greenhouse gases are the only thing that prevents that from happening. Water vapor is by far the major greenhouse gas but it is a condensing gas and once it condenses out into snow there is nothing but greenhouse effect from non-condensing gases to melt it.
I agree with Stephen Wilde
The water would condense out (as it does at the moment) but it would also be evaporating or even sublimating into the atmosphere dependent on the temperature and the atmospheric vapor pressure of the water vapor.
Humid air is lighter than dry air and will start rising with dry air moving in to replace it and pick up more water vapor. Therefore, there can be convection even without added heat. This convection will carry water vapor into the atmosphere where it will act as a ‘green house’ gas considerably more powerful than CO2.
It is extremely difficult to envisage the state of your hypothesis with completely dry atmosphere and all the water as snow or ice even at the equator.
The argument seems to be an extension of the AGW/IPCC postulate that water only evaporates due to CO2 radiative forcing and is such evaporation is ‘only a feedback’.
Unless someone can demonstrate that water will not evaporate or sublimate in a dry atmosphere at the equator – this postulate appears to be false.
If CO2 was reduced in a sudden step, the adiabatic lapse rate would increase. Rising moist air would cool faster as the rising air would intercept less IR from below. This must happen. My pet theory says that the result would be a drop in the mean height of the tropopause and a higher temperature there. This would slowly cause the humidity of the stratosphere to rise as the moisture in the stratosphere is controlled by the rising dew point of the lowered tropopause. The IR absorption of the stratosphere would rise. Once equilibrium is re-established, the net optical density of the atmosphere would be at the initial value with more water vapor absorption of IR and, of course, less CO2 absorption.
This is consistent with constant optical density theory of Miskolczi, the paper:
“Polynomial Cointegration Tests of the Anthropogenic Theory of Global Warming” by Michael Beenstock1 and Yaniv Reingewertz1; and the measured decrease in humidity at high altitudes over the last fifty years as CO2 has risen.
Mike Borgelt says: November 12, 2010 at 12:17 am
Anybody care to comment if pressure broadening of the CO2 absorption lines is dependent on absolute pressure or just partial pressure of CO2?
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CO2 lasers are common, but absorption line broadening is the reason why you can’t build a CO2 laser by starting with the correct pCO2 and adding nitrogen to make the total 1 atmosphere. The elastic collisions of too many nitrogen atoms distorts the shape of the CO2 atom’s electron cloud. (Anthropomorphic quantum physics anyone?)
Also, one of the reasons for Venus’ high surface temperature is the lack of convective stirring. No thunderstorms and no evaporation/condensation to carry heat upwards.
Phil,
“The measured LW forcing on the earth is ~300 W/m^2 even at the N Pole so that seems reasonable.”
I’m still not convinced. I made 2 calculations of the Stefan-Boltzman equation with surface temperatures of 255k and 287k to mimic a blackbody earth both with and without greenhouse effects. For the lower temperature I get a radiative flux of 240 w/sq meter, and for the higher temperature I get 385 w/sq meter. This is a difference of 145 w/sq meter. So if I’m reading this correctly, the entire forcing due to greenhouse gases is only 145 w/sq meter, so that due to CO2 alone can’t possibly be 258 w/sq meter.
RichieP says:
November 12, 2010 at 6:12 am
“I have come to the point in all these discussions where I find myself thinking that the scientific and political worlds have simply become mad.”
That is my feeling too. Madness, pure and simple. The ony way out would be to send a signal to Lacis & Co that, relax, we will give you money even though you study another molecule, too.
“”””” Mike Borgelt says:
November 12, 2010 at 12:17 am
Anybody care to comment if pressure broadening of the CO2 absorption lines is dependent on absolute pressure or just partial pressure of CO2?
Lacis claims Mars is cold because of lack of pressure broadening. “””””
Mike, the line broadening mechanism due to pressure, is essentially the collision rates, and mean free path issues. So it depends on just the total number of molecules in a volume, and not their species; so it is not a partial pressure effect.
Now bear in mind, that since each molecular species has its own molecular mass, the energy and momentum exchanges in collisions are somewhat dependent on who collides with whom; but that is just the fine print in the interractions. Shorter times between collisions leads to broader spectral lines.
The Temperature broadening is simply a Doppler effect since the average molecular velocity tends to vary as the square root of the Temperature (Kelvins) due to the Maxwell-Boltzmann distribution function.
Right on, Dave Springer!
I like the motto “Happiness is a warm planet.”
Well I read both of Andy’s posts on Roger Sr’s site and I don’t buy it.
He ends up by saying that removal of the non condensing GHGs would cause the H2O to simply precipitate out and rapid cooling.
Hey Earth to Andy; absent all those clouds that precipitated out, and the water vapor that isn’t there either; the ground level solar insolation goes sky high PDQ; it does not head for 255 K. What is the final albedo in your model; without that 70% cloud cover that NASA now tells us we do have.
All “Lukewarmers” are confusing.
Dave Springer says:
November 12, 2010 at 4:08 am
Phil. says:
November 12, 2010 at 7:18 am
George E. Smith says:
November 12, 2010 at 12:57 pm
Dan in California says:
November 12, 2010 at 11:23 am
Guys I’m only saying what Lacis claimed. The reason I ask is that I’m pretty sure I’ve seen Gavin claim that the extra CO2 in Earth’s atmosphere is a problem because of the extra pressure broadening. As the extra CO2 is negligibly small in the makeup of the total pressure this can’t be right.
I’m well aware of the Venus and Mars cases and if you do the calculation correctly you get something like 25 times as much mass of CO2 over each square meter of Mars as on Earth.
Dan, thanks for reminding us about the role of convection. On Earth, with aid of water vapor, it causes cooling.
I’m with you George. I’m coming to the conclusion that CO2 has a negligibly small effect on temperatures in the troposphere. Above the trop the decreased pressure broadening should let more radiation through the higher you go and there the extra CO2 may have a small effect.