The greenhouse effect is real. If there were no greenhouse gases in the atmosphere, earth would be a cold place. Compare Mars versus Venus – Mars has minimal greenhouse gas molecules in its’ atmosphere due to low atmospheric pressure, and is cold. By contrast, Venus has a lot of greenhouse gas molecules in its’ atmosphere, and is very hot. Temperature increases as greenhouse gas concentration increases. These are undisputed facts.
outgoing radiation = incoming radiation – changes in oceanic heat content
The image below from AER Research explains the radiative balance.
http://www.aer.com/scienceResearch/rc/rc.html
About 30% of the incoming shortwave radiation (SW) is reflected by clouds and from the earth’s surface. 20% is absorbed by clouds and re-emitted back into space as longwave (LW) radiation. The other 50% reaches the earth’s surface and warms us. All of that 50% eventually makes it back out into space as LW radiation, through intermediate processes of convection, conduction or radiation. As greenhouse gas concentration increases, the total number of collisions with GHG molecules increases. This makes it more difficult for LW radiation to escape. In order to maintain equilibrium, the temperature has to increase. Higher temperatures mean higher energies, which in turn increase the frequency of emission events. Thus the incoming/outgoing balance is maintained.
Click for larger image
http://www.aer.com/scienceResearch/rc/m-proj/lbl_clrt_mls.html
The important greenhouse gases are: H2O, CO2, O3, N2O, CO and CH4. The reason why the desert can get very cold at night is because of a lack of water vapor. The same is true for Antarctica. The extreme cold in Antarctica is due to high albedo and a lack of water vapor and clouds in the atmosphere, which results in almost all of the incoming radiation returning immediately to space.
An earth with no CO2 would be very cold. The first few tens of PPM produce a strong warming effect, and increases after that are incremental. It is widely agreed that a doubling of CO2 will increase atmospheric temperatures by about 1.2C, before feedbacks. So the debate is not about the greenhouse effect, it is about the feedbacks.
Suppose that the amount of reflected SW from clouds increases from 20% to 21%? That would cause a significant cooling effect. Thus the ability of GCM models to model future temperatures is largely dependent on the ability to model future clouds. Cloud modeling is acknowledged to be currently one of the weakest links in the GCMs. Given the sensitivity to clouds, it is perhaps surprising that some high profile climate scientists are willing to claim that 6C+ temperature rises are established science.
So the bottom line is that the greenhouse effect is real. Increasing CO2 will increase temperatures. If you want to make a knowledgeable argument, learn about the feedbacks. That is where the disagreement lies.
“I bicycle year round day and night, and am quite certain that my hands stay warmer on cloudy nights in the winter – due to back radiation from the clouds.”
Maybe it’s because water vapor has four times the thermal capacity of the rest of the air?
Joel Shore,
Please explain this statement via Gavin Schmidt et al 2005:
http://www.osti.gov/energycitations/servlets/purl/881407-xk2Sdg/881407.PDF
“Tropospheric warming is a robust feature of climate model simulations driven by historical increases in greenhouse gases (1–3). Maximum warming is predicted to occur in the middle and upper tropical troposphere.”
Or, as in Steve McIntyre’s words, has the Team decided to “move on”? Have they abandoned the “basic planetary physics” learned in high school we’ve been told about?
Who has falsified Miskolczi’s hypothesis?
Miskolczi
http://www.landshape.org/dokuwiki/doku.php?id=introduction
Everyone, including Steve Goddard, should read it.
BTW, where are the experiments demonstrating the greenhouse effect? Also, the notion that from 1993-2003 OHC is driven by increases in GHG is supported by what first principles in physics? It appears to be a perpetuum mobile.
“This is apparently a correct description of the ’skeptic argument’”
Wrong again, Phil.
Dr. Roy Spencer succinctly states the AGW/CO2 skeptics’ argument:
No one has falsified the hypothesis that the observed temperatures changes are a consequence of natural variability.
Get back to us when you think you’ve falsified the theory of natural climate variability.
MattN (09:03:00) :
Can you point me to the posts that flat out deny that CO2 causes any warming? I’m not seeing them. I do not think any of the “regulars” on here believe that.
I must have been dreaming. Thank you for your assurance that all the ‘regulars’ believe that “adding CO2 increases temperature” (as you first put it).
John,
I’m sure Nebraska is a lovely place, but I’m still trying to figure out where Springfield is.
Leif Svalgaard (08:15:03) :
The greenhouse effect is not that CO2 warms up, or that the air around the CO2 warms up, but simply that any energy CO2 absorbs [most of it coming from below] is immediately re-emitted, half up into space and lost and half downwards back to the surface.
Calculation shows that collisional frequency is at least 4 order of magnitude higher than the frequency of a re-radiation. Thus the de-excitation of CO² molecules mostly occur by kinetic energy and pseudo thermalization of the molecular system. Even if re-radiation occurs, see below.
The surface thus heats up and warms the air by conduction and convection.Second law of thermodynamic prevents that the cooler atmosphere could warm the warmer surface without work. It is just not possible that surface is additionally warmed by this re-radiation.
General: the whole discussion borders on complete chaos, people stating this and that with wild abandon, all claiming it is ’simple physics’. No amount of factual information can change all these misconceptions.
What is true is that physical laws can not be broken to fit misconceptions.
Bye,
TMTisFree
p.s. – the correct term is “steady state” when the flows in and out are equal, which is virtually never, not “equilibrium.” (that was one of my prof’s pet peeves, and so I made it one of mine.)
pardon my french, but this is just as much baloney as would be expected from Mann, or Hanssen, or any other Wall Street guru … namely trying to quantify something that is unquantifyable … trying to invent Ohm’s law where Ohm law isn’t feasable, possible, where Ohm’s law simply DOESN’T EXIST … I hardly can read it, but “70 outgoing” ? … where’s the measuring station ? .. why not 60 ? … why not 80 ? … I can understand that everybody wants to mirror their own science to Sir Newton’s F=ma, but first he was a genius, and second he tackled a very simple problem … let’s revisit William of Occam before we try to “prove” something … or Yogi Berra …
The “Estimated Clear Sky … ” graph rather assumes a spherical horse.
The point about Mars and Venus is bogus. Given similar atmospheseres to Earth’s, MArs would still be colder and Venus hotter.
Steven Goddard says: “Heat flow is driven by temperature differences. If the atmosphere is warmer over the ocean, then less heat flows out of the ocean into the atmosphere, and the ocean warms up. And vice-versa.”
From oceanographers, and I do not have the names handy, my understanding is that the oceans receive virtually all their heat from shortwave radiation from the sun, which means that the temperature of the air has little to do with ocean temperature. Oceans cool by radiating long wave radiation. This has little to do with whether the air is warm or cool above but more whether the sky is clear. Oceans in tropical areas are warmer that the polar ones because they receive more radiation. Currents rediatribute the heat as is also done in the atmosphere. Steve’s post stopped at the feedbacks. Yes, this is very little understanding of this, modelling as a result is poor, there are no accurate measurement, therefore we have a difficult time attributing what factors are causing the temperature changes. Yes, there is a greenhouse effect, but its main result is keeping a heat balance above freezing. The first parts of hreenhouse gases give the most warming, then the effect decreases logarithmically. Then there are the disputed feedbacks.
Leif Svalgaard (08:15:03) :
The greenhouse effect is not that CO2 warms up, or that the air around the CO2 warms up, but simply that any energy CO2 absorbs [most of it coming from below] is immediately re-emitted, half up into space and lost and half downwards back to the surface. The surface thus heats up and warms the air by conduction and convection.
Leif, the bolded statement is only true high in the atmosphere, ~stratosphere, near the surface any energy is exchanged via collisions with neighboring molecules almost immediately (timescale less than a nanosecond).
Increased CO2 is of course not the only factor affecting in the climate. If a huge volcanic eruption occurred, like Krakatoa, I suspect things would get a bit chilly regardless of how many Hummers and cows were belching out GHGs.
Glacial cycles vary the temperature by 10C, so one might convince themselves that there are also other factors influencing the climate. Over the last 10 years, temperatures have declined, despite all the Hummers and cows.
Steven,
Would it be possible to give an explanation/interpretation to the spectral cooling rate graphic shown in your discussion above. Alternatively could you provide a reference to read. BTW the link to AER does not provide the info, as far as I can tell.
Thanks.
“I bicycle year round day and night, and am quite certain that my hands stay warmer on cloudy nights in the winter – due to back radiation from the clouds.”
Steve, I think you may have published prematurely. Presenting the “Climate Science” POV would have been unexceptionable.
Cloudy nights in winter are often examples of thermal inversion and higher relative humidity. Another pillar here recently had a similar example. You’ve dropped convection and evaporation out of your mix, however anecdotal.
In any case, we’ll give you a mulligan.
Isn’t the effect of co2 logarithmic? It will never stop having an effect but the additional warming effect will become less and less, approaching zero but never reaching it. This is why without unprecedented “feedbacks” co2 cannot cause a “runaway”. I won’t lose any sleep over < +2.0C with the next doubling sometime in the 23rd century.
Smokey (09:41:07) :
“This is apparently a correct description of the ’skeptic argument’”
Wrong again, Phil.
Dr. Roy Spencer succinctly states the AGW/CO2 skeptics’ argument:
No one has falsified the hypothesis that the observed temperatures changes are a consequence of natural variability.
Really, and what relevance does that have to the ‘skeptic argument regarding saturation’?
Phil. (09:22:57) :
tmtisfree (08:44:09) :
george h. (06:22:56) :
“My understanding of the skeptic argument regarding saturation is this: At current CO2 concentrations, all of the available IR in the relevant bands (2.7, 4.3 and 15 µm) is already captured. This is about 8% of the whole IR spectrum, which means that 92% of the IR passes right through without being absorbed by CO2. If the entire atmosphere were composed of nothing but CO2, it would still only be able to absorb 8% of the radiant heat. So if all of the available IR in that spectrum is being captured at current concentrations or lower, then adding more CO2 to the atmosphere won’t matter a bit.”
This is fundamentally correct.
“This is apparently a correct description of the ’skeptic argument’, however as far as the science goes it is fundamentally flawed.”
Perhaps you can enlighten us all as to “how” this is “fundamentally flawed”
Gerald Machnee,
Cold air over ocean causes fog, which blocks LW. During the miserably cold California summer of 1998, I remember that we were lucky to get an hour of sunshine at noon on the beaches south of Santa Cruz. I also remember bundling up in several blankets to watch the fireworks.
“The coldest winter I ever spent was my summer in San Francisco”
Mark Twain
Steven Goddard (09:57:16) :
Glacial cycles vary the temperature by 10C
To clarify, whilst the ice cores show that change in Antarctica, the global mean is judged to have been less – in the range of between 4C and 7C.
gary gulrud,
Cycling on a 20F cloudy night is much more comfortable on your hands than a 20F clear night. This is because of back radiation from the clouds.
Dear Steve & all, about oceanic heat uptake and Jim Hansen’s warming “in the pipeline” due to the lagged response of the oceans, pleasae see the study
Urban, Nathan M., and Klaus Keller, 2009. Complementary observational constraints on climate sensitivity. Geophys. Res. Lett., 36, L04708, doi:10.1029/2008GL036457, February 25, 2009, preprint online http://www.geosc.psu.edu/~kkeller/Urban_Keller_grl_08_submitted.pdf
Abstract
“A persistent feature of empirical climate sensitivity estimates is their heavy tailed probability distribution indicating a sizeable probability of high sensitivities. Previous studies make general claims that this upper heavy tail is an unavoidable feature of (i) the Earth system, or of (ii) limitations in our observational capabilities. Here we show that reducing the uncertainty about (i) oceanic heat uptake and (ii) aerosol climate forcing can—in principle—cut off this heavy upper tail of climate sensitivity estimates. Observations of oceanic heat uptake result in a negatively correlated joint likelihood function of climate sensitivity and ocean vertical diffusivity. This correlation is opposite to the positive correlation resulting from observations of surface air temperatures. As a result, the two observational constraints can rule out complementary regions in the climate sensitivity-vertical diffusivity space, and cut off the heavy upper tail of the marginal climate sensitivity estimate.”
The authors write e.g. as follows:
“A given surface air temperature change is consistent with either
a relatively large heating which is penetrating rapidly
into the oceans and delaying some of the surface warming
(i.e., a high climate sensitivity and a high ocean diffusivity),
or a relatively small heating which is penetrating slowly into
the oceans so the surface warming is quickly experienced
(i.e., a low climate sensitivity and a low ocean diffusivity).”
As far as I can see, this fundamental point is still unsolved, otherwise the authors needed none of these considerations.
Lucy Skywalker (08:06:25) :
> Ric your hyperlink is not working.
It worked for me just now from work.
http://wermenh.com/climate/climate2009.pdf
What sort of error did you get? It is a pretty big file (about a MB), I think there’s one image that is bloated, but it shouldn’t cause trouble.
http://wermenh.com/climate/index.html is small and easy on browsers, does that fail too?
I have had some trouble with various ISPs blacklisting the ISP that is hosting wermenh.com, but those have been mainly Email issues, not HTTP issues.
This is probably OT but perhaps someone could enlighten me a bit.
From reading (traditional books as well as on-line) I am puzzled by ionizing radiation and cloud formation.
C T R Wilson developed the cloud chamber in the late 19th century. He removed dust from the chamber and still was able to create “cloud”; he fired X-Rays at the chamber and “cloud” formed. When Wilson showed strange cloud tracks to Rutherford, the chamber was used by Rutherford to study sub-atomic particles and radio-active decay. Therefore ionising e-m radiation and sub-atomic particles have the potential for cloud formation.
I have just read the supernova events are detectable in ice core through excess nitrogen oxide created as a result of ionisation of Oxygen and Nitrogen by gamma radiation.
My guess is that ionising radiation entering the atmosphere cycles in intensity over time. So if there are measurable changes in the ice record is there any correlation to climate.
I did wonder if there were any historical records of climate warming/cooling after SuperNova but all I found was unusually severe winters in 1046,1048 and 1054 in the Anglo Saxon Chronicle.
These pre-date the supernova of 1056. Neither are they an indicator of a globally cooling climate. But I did wonder if a Nova was preceded by an increase in radiation or are they “digital” in character with no prior indication?
Are there any studies of ice cores, tree rings or written records which show any cause and effect or is it too small to be measurable?
Mark (06:36:27 wrote :
“Has there ever been a study that involved a bunch of greenhouses where each had different amounts of CO2 (all other factors equal) and all subjected to the same amount of sunlight to see how the different CO2 levels affect temperature?”
Winner, winner, chicken dinner. Excellent question.
Or take two “aquariums” with walls of whatever material is most transparent to infrared.
One filled with normal atmosphere and one filled with pure CO2. Both partly filled with water.
Shine infrared lights on both. Any difference in the rise in and final equilibrium temperature of the atmospheres and water?
REPLY: The experiment is too simple to replicate our atmosphere – Anthony
Steve, I suspect you’re illustrating part of your article with a spurious description of climate sensitivity (“Estimated Clear Sky Greenhouse Effect from Quadrupling CO2”). This seems to be a figure taken from a site entitled “Junk Science”.
Not only do these illustrations (Charnock and Shine; Kondratjew and Moskalenko; Lindzen) bear very little relationship to our current understanding of climate sensitivity, the examples chosen are dubious in themselves. Here’s why:
Charnock and Shine (+2.92 oC per quadrupling of CO2)
There are only two publications by Charnock and Shine (together) in the data base. These are both correspondences (letters) written in the magazine “Physics Today”. The letter that addresses climate sensitivity states:
“Corresponding estimates of the effect on the mean surface temperature of the Earth are much more complicated, as both Campbell and Tomkin say. But using a simple radiative convective model,1 with no other change, one finds that doubling the CO2 produces a 1.5 °C warming and removing it a 12 °C cooling. Including a simple relative humidity feedback (but no ice-albedo feedback) changes these values to 2.4 °C warming and 17 °C cooling”
Charnock H, Shine KP (1993) CO2s Greenhouse Contribution Debated Physics Today 4646, 66-66
So Charnock and Shine consider that doubling atmospheric CO2 results in around 2.4 oC of warming even without ice-albedo feedbacks. This equates to near 5 oC for a quadrupling of CO2…not 2.92 oC according to the Junk science picture. The albedo feedback will increase that value.
Can you help us out with this? Perusal of KP Shine’s recent publications (H Charnock focuses on ocean science at present) indicates that Shine is in the mainstream scientific view that raising atmospheric CO2 levels has problematic consequences and in fact has written recently on the fact that some of the other anthropogenic greenhouse gases are going to add significantly to the problem and need to be addressed too [e.g. K.P. Shine and W. T. Sturges (2007) CO2 Is Not the Only Gas. Science 30 March 315, 1804 – 1805]
Kondratjew and Moskalenko (+ 1.75 oC per quadrupling of CO2)
I can’t find a paper by these two in the database. I’ve tried some alternative spellings without luck. Could you please clarify the citation?
Lindzen
The only published paper of Lindzen’s I can find that addresses this point specifically is:
Schneider EK, Kirtman BP, Lindzen RS (1999) Tropospheric water vapor and climate sensitivity J. Atmos. Sci. 56, 1649-1658
But here he does a load of modelling under different parameterizations/scenarios and doesn’t come up with a particular sensitivity. Otherwise one can find “advocacy” web articles by Lindzen in which he suggests that enhanced CO2 will cause the troposphere to “dry” such that the water vapour feedback is negative (real world measurements indicate categorically that that notion is incorrect) or papers on a hypothesis about an “IR Iris Effect”.
So again it would be helpful to know where the junk science number came from!
Of course there is a very large number of analyses of climate sensitivity from modelling, from analysis of transient temperature responses to the solar cycle, from transient responses to volcanic eruptions, from analysis of paleotemperatur/paleoCO2 data during the recent and the deep past. A recent review[***] discusses around 30 of these analyses. These indicate that the climate sensitivity (equilibrium temperature rise for doubling atmospheric CO2) is likely to be between 2.0 and 4.5 oC with a most likely value around 3 oC These equate to a temperature rise from quadrupling CO2 of between 4 and 9 oC with a most likely value near 6 oC.
Of course one may not like these numbers, but they are what the scientific evidence supports. I wouldn’t use manifestly dubious junk science in any discussion of climate sensitivity.
[***]R. Knutti & G. C. Hegerl (2008) The equilibrium sensitivity of the Earth’s temperature to radiation changes Nature Geoscience 1, 735 – 743 (2008)
REPLY: As usual, you overanalyze. The graph is simply there to show laypersons the logarithmic nature of CO2 response. And clearly with such broad disagreement, nobody has a handle on the magnitude of doubling or quadrupling CO2. – Anthony