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.
” if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool”
Of course it would cool… the earth would be come a dead rock since CO2 is part of the life cycle. There would not be any plants that would take up the CO2 to make oxygen… it would be another snowball earth.
The comment was:
“First, I agree with Andy’s conclusion that if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool.”
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Some scientist you are!
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Removing CO2 would cause the world temperatures to WARM, and NOT cool.
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Without CO2, no plant would survive.
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Without plants on the surface, there would be bare earth on every land.
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Without plants, there would be no transpiration, and the land would become a living hell for any living creature.
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Oh, and then there’s this: What about Mars?
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It’s got all the CO2 in the world, and yet it’s a freezing hell.
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Go ahead, Mr. Scientist, tell us all about that!
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Why is Mars a freezing Hell, yet Venus is a roasting misery, what with all that CO2.
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Can’t have it both ways, Mr. ‘Scientist.’
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And DO NOT be talking about the Sun. The issue here is JUST CO2, and NO THING ELSE.
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You’ll be getting back on that, won’t you, real soon now, Mr. Scientist?
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Right?
REPLY: This is just rude juvenile trolling, I suggest readers ignore this poster – Anthony
The concept of carbon dioxide as a climate thermostat is complete nonsense. You only need to look at a chart showing global temperature and carbon dioxide concentration through geologic ages to see that. Global temperature was warm but did not fluctuate much from Cambrian to Cretaceous except for the ice ages. Carbon dioxide, on the other hand, was all over the place In the Cambrian it was close to 6000 ppm while in the Cretaceous it was between 1000 and 2000 ppm. The fact that this amount of variation in carbon dioxide had no influence on global temperature tells us that carbon dioxide was not the thermostat. But something had to account for the stability of the temperature over millions of years. If it wasn’t carbon dioxide the only alternative is water vapor and these guys better get to work on that. Oceans are an infinite source of water vapor and it should not be too hard to identify the feedback loop involving temperature and evaporation that must be involved.
It is well known the the main problems posed by global warming on land is not the higher temperature per se but the concurrent changes in rainfall patterns and possible sea level rise. However the temperature rise in the oceans is directly affecting coral reefs and causing phytoplankton decline, plus the impact of lower ocean pH threatens many life forms needs to be taken into account when deciding if mitigation measures should be taken.
Also the logarithmic relation between CO2 ppmv and radiative forcing and the roughly exponential increase in CO2 ppmv give at least a linear relation in addition to which one has to consider various feedbacks which are mostly positive. Will clouds save us? No one has been able to show that they will. And if the world gets more cloudy, would the increase in clouds negatively impact land and sea plant life by reducing the amount of visible light? CO2 is plant food sure, but rainfall (on land) and light matter a great deal.
In reply to 899:
I can’t tell you the difference between mars and venus, it’s called density.
The atmospheric pressure on mars is a minute fraction of what it is on earth and on Venus it’s almost 100 times as dense as it is here. I guess you missed science class in high school…
me
If only we had an environment on this planet where we could test a lack of CO2, like we have with regards to H2O. I suppose deserts don’t really get cold at night, not with all that CO2 to keep them warm. Who needs observation when we have theory?
If you truly want the Earth to rapidly cool, you’d have to remove the water vapor first.
Mike says:
Corals evolved when the pco2 was 12 times what it is now and phytoplankton did fine too. In fact there was more oxygen than there is now.
Mike asks: ” Will clouds save us? No one has been able to show that they will”.
??????????????????
Mike, many of us are not looking to be saved. Not by clouds and not by you guys’ passion for melodrama.
Is there any chance that you could save the world more quietly?
It occurs to me that a rising plume of condensing air saturated with water vapor must contain an anomalous population of newly formed or newly augmented aggregates or clumps of water molecules that have been excited by the heat of condensation released by the formation of a new polar hydrogen bond. For the most part, that energy must be shared with the surrounding atmosphere as this is the reason the lapse rate cooling of rising wet air is only 3.3 degrees F per thousand feet as opposed to the 5.5 degree F cooling per 1000 feet for dry air.
It seems to me that these aggregates on initial formation or augmentation should also have a limited probability of radiating photons characteristic of the initial thermal shock of hydrogen bond formation. As I have seen no mention of this fact, I assume either this effect is known to be insignificant or has never been considered worth a detailed study. I would expect this initial condensation radiation would only be absorbed by the Earth or a similar H2O aggregate. Thus I believe that outward bound photons of this type, from the top of a plume of condensing air, should have a good chance of escaping to outer space at altitudes where radiation from CO2 or H2O molecules would readily be re-absorbed by similar molecules above.
At this time I have a perception, due to all the unsupported speculation (including this) I have on seen, that the process by which convected thermal energy is eventually radiated by the atmosphere to outer space is not well known.
Below is a reference to an obscure and highly technical paper on bimolecular water absorption as an attempt, I believe, to estimate the contribution of bimolecular water to surface-level heat trapping. It does include a diagram of this molecular complex (which is actually less massive than a single CO2 molecule.) Note that there is a potential vibration mode along the axis of the two linked oxygen molecules that monomolecular H2O cannot match.
“Field Measurements of Water Continuum and Water Dimer Absorption by Active Long Path Differential Optical Absorption Spectroscopy (DOAS”) [PDF]
http://archiv.ub.uni-heidelberg.de/volltextserver/volltexte/2006/6686/pdf/dissertation_lotter.pdf
@899
wow seriously (don’t you think your being a bit rude)?
you raised valid points, but could have been more polite
An interesting website the author should familiarize himself with is located here. http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003440/
From a close inspection of the visualizations it is quite apparent that all the CO2 production increases from the US are coming from the heartland and more in particular where human populations are lowest. How odd. It also indicates and verifies to a large extent that humans contribute only a small fraction of the CO2 generated on this earth. This consistent with humans contributing anywhere from 3-4% of the total CO2 per year (how that’s tabulated remains to be verified). The arguments of tipping points arise from this. What you don’t see: You don’t see pockets of CO2 generation from coal fired power plants. For example, I don’t see a hot spot of CO2 concentration where I know for a fact coal burning power plants exist and they aren’t sequestering a resolution problem? Note how the coasts, Land vs Ocean vary in concentration. The visualizations and the graph indicate a concentration resolution on the order of a few ppm or better so surely you’d be able to observe cities or power plants spewing huge amounts of CO2. Surely all the extra CO2 in FOC (fly over country) would cause the rural temperatures to be higher but we don’t see this in the record. How’s that local forcing working out for you in Boulder? Note also how “well” mixed the atmosphere is. +/- 20ppm across the globe. Perhaps someone could explain to me why the Himalayas have such a huge carbon footprint compared to Bejing and surrounding areas? Plant growth perhaps? Wouldn’t it be funny if the CO2 increase was more due to an increase in flora?
Didn’t James Hansen indicate that South America and Africa didn’t matter..looks like he’s right with respect to CO2 concentrations in the July time frame. The bottom line: Models not verified by experimentation are worth little, models that can’t predict results are worth less.
What the “warmistas’ are actually implying is they want to destroy the oceans because they’re generating so much CO2. They want to wipe out FOC because all the people there are generating CO2. They want to level the Himalayas because they spewing so much more CO2. Maybe they should plant more strip bark trees…and strip the bark more often. Cellulose is a good carbon sink, isn’t it?
Mike says: November 11, 2010 at 9:58 pm
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All of the scare stories are, however, still on the computer screen only, n’est-ce pas?
Regarding the sea-level change, this is a summary of 105-year monitoring of Japanese tide gauges by our MET:
http://www.data.kishou.go.jp/shindan/a_1/sl_trend/sl_trend_graph.png
Thouh the satellite era data over a short period (from 1992) by the Colorado group agrees fairly well with the above graph, our MET says that “no long-term trend is seen” and “a 20-year oscillation pattern is obvious.”
My previous post refers to the following part in Mike’s comment:
“…..the main problems posed by global warming on land is not the higher temperature per se but the concurrent changes in rainfall patterns and possible sea level rise. “
899 says:
November 11, 2010 at 9:42 pm
You might want to think about switching to decaf…….. Just a thought.
On Mars, the relative CO2 pressure is 16 times that on Earth. The absolute CO2 amount (per surface unit) on Mars would translate to about 5000 ppm CO2 on Earth !!
And all that HUGE amount of CO2 translates in a tiny increase of 3 kelvin from the -56C radiative temperature to the -53C observed average temperature.
CO2 isn’t working as a greenhouse gas on Mars. Indeed it’s working as a cooling agent as long as it CONDENSES in the form of CO2 ice on the martian poles raising the very low martian surface albedo.
Oliver Ramsay says: (November 11, 2010 at 10:50 pm ) Is there any chance that you could save the world more quietly?
A very fine sentence, Oliver.
My reading of the Hadean Earth, is that the crust was too hot for the persistence of any carbonate minerals. All of the CO2 in the carbonate deposits now on Earth would have been in the atmosphere. Planetary scientists typically describe the atmosphere of that time as consisting of 60 to 100 bars of CO2, plus about 1 bar of dinitrogen. See here for example, and here.
Chemical weathering, after Earth cooled enough to form a solid crust plus a world ocean, removed CO2 from the atmosphere as carbonate precipitates. Tectonics subducted the carbonate, which is one big reason why CO2 now emerges from volcanoes. But the original CO2 was probably accreted by the primordial Earth, not outgassed from volcanoes.
Calculations, such as here, say that most of the early CO2 would have been scrubbed from the atmosphere, leaving less than the 1 bar needed to avert a frozen ocean. So, the earliest Archaean Earth (the period after the Hadean) would have been frozen, because of the early faint sun, but with only thin ice at the tropics. It’s noted that there would have been century-long “impact summers” when one of the much more numerous bolides came crashing down, which was fairly often. Interesting place, early Earth.
But anyway, these days, the sun is about 30% brighter than it was 4 billion years ago. So, it’s not clear that loss of CO2 would produce a fully frozen surface, anymore. As Ray points out, loss of CO2 would, of course, produce a dead planet.
Mike wrote: “Also the logarithmic relation between CO2 ppmv and radiative forcing and the roughly exponential increase in CO2 ppmv give at least a linear relation in addition to which one has to consider various feedbacks which are mostly positive.”
Exponential increase in CO2? Is the rate of increase exponential? I’d like to see some support for that.
Various feedbacks are mostly positive? That is nothing but a belief-based statement without any basis in reality. There is essentially zero evidence that the various feedbacks are mostly positive. Unless of course you believe that a priori assumptions built into computer models constitute evidence . . .
One takeaway for me here is that since CO2 is a non-condensing GHG, it could actually help moderate temperature drops during periods of heavy precipitation. A climate moderator rather than disruptor. It seems an interesting synergy, CO2 (plus other NC GHG’s) and H2O, with water capable of storing and liberating far more heat, and non-condensors backfilling during periods of unusual condensation. A little more CO2 is good as humidity falls. Steve Goddard did a short piece recently noting that if the entire atmosphere were (suddenly and briefly) 100% CO2, (without increased density) far less IR could be absorbed, and temperature would plummet. The combination appears quite beneficial.
I’d be very interested to see what GISS ModelE said happened to the cloud cover when CO2 was reduced to zero, and what forcing that produced at ground level.
Mr Barney says: In reply to 899:
“I (can) tell you the difference between mars and venus, it’s called density.
The atmospheric pressure on mars is a minute fraction of what it is on earth and on Venus it’s almost 100 times as dense as it is here. I guess you missed science class in high school…”
No to mention parts of kindergarten.
I notice now that the answer to my question is provided in the first of Andy Lacis’ guest posts at Roger Pielke’s blog.
What a ridiculous article that’s been posted here. Why not say the earth’s orbital variances are the earth’s thermostat. Maybe plate tectonics and the accompaning continental uplift resulting in mountains is the earth’s thermostat. I agree with Arno Arrak’s comments above regarding geological evidence.
Misquoting a well known Lyellism: “The past is the key to the present”, and CO2 concentrations have no correlation to paleotemperatures. I refer you to this article on this website back in 2009: . Also go to Christopher Scotese’s website and read Ian Plimer’s book for more information. Geology Rules!
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.
The article I refer to above is found at the URL address: http://wattsupwiththat.com/2009/10/16/searching-the-paleoclimate-record-for-estimated-correlations-temperature-co2-and-sea-level/ and is missing from my comments. Sorry guys and girls I messed it up!