A short primer: The Greenhouse Effect Explained

Guest post by Steve Goddard
There is a considerable amount of misinformation propagated about the greenhouse effect by people from both sides of the debate.  The basic concepts are straightforward, as explained here.

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.

Heat is not “trapped” by greenhouse gases.  The earth’s heat balance is maintained, as required by the laws of thermodynamics.

outgoing radiation = incoming radiation – changes in oceanic heat content

The image below from AER Research explains the radiative balance.

Radiation & Climate Slide

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.

It has been known for a long time that even a short column of air contains enough CO2 to saturate LW absorption.  This has been misinterpreted by some skeptics to mean that adding more CO2 will not increase the temperature.  That is simply not true, as higher GHG densities force the temperature up.  There is no dispute about this in the scientific community. See the graph below:

Click for larger image

As Dr. Hansen has correctly argued, increases in atmospheric temperature cause the ocean to warm up.  Thus changes the oceanic heat content become the short term imbalance in the incoming/outgoing equilibrium equation, which is not shown in the AER diagram.
The image below shows GHG absorption by altitude and wavenumber.  As you can see, there is a strong absorption band of CO2 at 600/cm.  That is what makes CO2 an important greenhouse gas.

Spectral Cooling Rates for the Mid-Latitude Summer Atmosphere

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.

Lisa, in this house we obey the laws of thermodynamics
– Homer Simpson

Addenddum:
The GHG/stoplight analogy
Suppose that you have to drop your child at school at 8:00 and have to be at work at 8:30.  There are 10 stoplights between the school and the office.  Your electric car has a fixed maximum speed of 30MPH.  It takes exactly 30 minutes to drive there.
If the city adds another stoplight (analogous to more CO2) the only way you can make it to work on time is to run traffic lights and/or get the city to make the traffic lights more efficient at moving cars (analogous to higher temperature.)  The radiative balance has to be maintained in the atmosphere, so the outgoing radiation has a fixed amount of time to escape, regardless of how many GHG molecules it encounters.   Otherwise, Homer and your boss will be very angry at you for violating the laws of thermodynamics.
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Policyguy
February 25, 2009 11:04 pm

Steve,
Here is an excerpt from your post on 2/21
“Consider the earth 14,000 years ago. CO2 levels were around 200 ppm and temperatures, at 6C below present values, were rising fast. Now consider 30,000 years ago. CO2 levels were also around 200 ppm and temperatures were also about 6C below current levels, yet at that time the earth was cooling. Exactly the same CO2 and temperature levels as 14,000 years ago, but the opposite direction of temperature change. CO2 was not the driver.
Now consider 120,000 years ago. Temperatures were higher than today and CO2 levels were relatively high at 290 ppm. Atmospheric H20 was high, and albedo was low. According to the theorists, earth should have been warming quickly. But it wasn’t – quite the opposite with temperatures cooling very quickly at that time. CO2 was not the driver.
If CO2 levels and the claimed lockstep feedbacks controlled the climate, the climate would be unstable. We would either move to a permanent ice age or turn into Venus.”
So, if not CO2, maybe its clouds? And what drives the clouds? Is there room for a solar component too? Are the GCM’s even capable of considering these variables or should we start from scratch?

David Corcoran
February 25, 2009 11:08 pm

The argument really isn’t about a slight AGW effect (few disagree over that), it’s whether Catastrophic Anthropogenic Global Warming (CAGW) will engender a runaway greenhouse effect that will turn our planet into a mirror of Venus in no time at all, geologically speaking.
For instance: Dr. Hansen says the seas will rise 25M in 91 years, I don’t know why low lying nations are stubbornly insisting on making him a liar.

Mark N
February 25, 2009 11:15 pm

Thanks, reads like a simple explanation that I could perhaps give it to ten year olds (or is there a better source of information for them?). Was wondering about H2O. I was under the impression that it is the major GHG. Thanks for your patience.

Bill Yarber
February 25, 2009 11:24 pm

Your use of Mars, Earth and Venus to prove that CO2 putis a major green house gas is totally flawed. You completely neglect their diameters and their distance from the Sun. Venus is 2/3s the distance from the Sun than earth and less than 1/2 that of Mars. Ergo, since the watts/sqm of the Sun’s out decreased with the square of the distance from the Sun, Venus gets over twice the energy that Earth gets and four times the energy Mars gets. Venus is warmer because it has a denser atmosphere and gets twice the energy Earth gets. This would be true if Venus had no CO2 in its atmosphere. Each planet has a different diameter but the difference is insignificant when compared to the impact of their individual orbit radii.
Bill

kevindick
February 25, 2009 11:26 pm

It seems like there are actually two things you need to know. You need to know the 1st order sensitivity to a doubling of C02 and you need to know the total feedback. So it’s pretty important to know whether the 1.2C number for 1st order sensitivity is right.
What do you think of Miskolczi’s work reassessing this sensitivity? My partial differential equation days are 20 years behind me, but I’ve read his paper and his argument seems superficially coherent.
I don’t feel qualified to fully judge the results though. It would be easy to sneak a specious mathematical argument by my given the current degraded state of my skills. Do you know any serious mathematical physics types that have reviewed his work and formed an opinion? Thanks.

February 25, 2009 11:30 pm

“It has been known for a long time that even a short column of air contains enough CO2 to saturate LW absorption. This has been misinterpreted by some skeptics to mean that adding more CO2 will not increase the temperature. That is simply not true, as higher GHG densities force the temperature up.”
Utterly ridiculuous and contradictory. If CO2 absorption is “saturated”, adding more CO2 cannot have any effect. Period.

Jim G
February 25, 2009 11:33 pm

Can someone double check this?
It appears the maximum CO2 effect is centered at a wavenumber of 650.
wavenumber = 1/lambda (in cm)
=> @ 650cm-1, lambda = 15.38 um
lambda (in um) = 2897/T (in deg K)
=> T = 2897/lambda
= 188K, or -121F (-85C)
The graph also shows that the CO2 absorption is at high altitude. ~10mb.
At 50F (10C) lambda should be about 977 which would be in the H2O absorption region.
Am I missing something? Obviously the heat radiated from the earth’s surface isn’t going to be -85C.
Is this why there should be a CO2 hotspot in the troposphere above 100,000 ft?

Steven Goddard
February 25, 2009 11:35 pm

Mark N,
Temperatures are very sensitive to H2O levels, particularly at night. Which is why deserts get cold at night. H2O is the most important greenhouse gas.
PolicyGuy,
Good questions. It is clear from the ice core records that there are other cyclical drivers of climate which can vary temperatures by 10C or more. CO2 is higher now than it has been in recent centuries, and Dr. Hansen asserts that the recent rises will overwhelm the natural variation.
Some climate models do consider TSI changes due to solar cycles. Cloud formation is not well understood or modeled. Weather forecasting models often mispredict clouds on the same day.

Richard111
February 25, 2009 11:39 pm

I have lived many years in desert climates and well remember the temperature drop after sunset. Part of my duties was to note the relative humidity. It drops during the day and increases during the night, so much so that you could get condensation, dew, at dawn. This is what most desert creatures seem to survive on.
This is a personal observation. I would be interested to learn how heating the air would reduce the water content. As I understand, you must cool the air to get the moisture out. Just because deserts are hot and surface dry does not mean there is less moisture in the atmosphere. The air that blows in from cooler climes to replace the rising air over the desert does not lose its moisture. Deserts are dry. Usually.

Steven Goddard
February 25, 2009 11:39 pm

Molon,
What you are not considering is that LW is absorbed and emitted many times on it’s tortuous path out of the atmosphere. The more GHG, the more times it is absorbed.
Your argument is analagous to saying that one stop light has the same effect on your commute time as does 100 stop lights.

John F. Hultquist
February 25, 2009 11:51 pm

Holy Cow! Your first diagram doesn’t show any longwave radiation in the Solar spectrum which is +/-50% depending on your choice of the wave length for the boundary. Seems that might at least be mentioned.
“There is no dispute about this in the scientific community.”
“It is widely agreed that a doubling of CO2 will increase
atmospheric temperatures by about 1.2C before feedbacks.”
Neither of these is true.
David Archibald claims an increase to 620 ppm, projected by 2150, will raise the temperature by only 0.2 degrees C. (May 2007) in “The Past and Future Climate.”
“An earth with no CO2 would be very cold.”
Proof? Why should this be as H2O and the other gases you mention don’t rely on CO2 to work as GHGs.
Also, AGW is “widely” questioned and even if it is “widely agreed” that doesn’t make it true. The references to Mars and Venus don’t help. The situations are so different you set me thinking about other topics.
Is the phrase “before feedbacks” meant to imply positive feedbacks?
How do you explain the cooling after 1940 to 1977 while CO2 was increasing and with no change in that trend a warming began in 1977?
Now for the past ten years temps have not continued there rise, even decreased some, and CO2 has not stopped going up?
Most reading this will be aware of or can easily find on WUWT material questioning the straightforward and undisputed facts you present so I haven’t bothered to add sources here. If anyone needs these, say so.
Your short primer appears not just to be short in length but short in its explanatory power. Give it another try. There are many of these short explanations on the WEB so I think this one is a set-up of some kind. I can’t figure out, though, just what the purpose is.

manse42
February 26, 2009 12:00 am

I feel lost…
Isn’t the enthalpy and specific heat capacity somehow missing?
The potential heat content of the entire atmosphere above 10mb is less than 1/100 (because of lack of water vapours high heat capacity) of the potential heat content below 10 mb.
And it is above 10 mb the big CO2 effect comes is as I read the chart…

Steven Goddard
February 26, 2009 12:01 am

Richard111,
Relative humidity means just that – relative to the temperature. You can change the relative humidity without changing the absolute humidity, by heating or cooling the air. The Utah desert can have swings of 60 degrees between day and night with no changes in the very low absolute humidity. As soon as water starts condensing due to cold, it releases heat and limits further temperature drops.

Robert David Graham
February 26, 2009 12:04 am

Thanks for the post. I’ve long been frustrated by friends claiming “there is no greenhouse effect” or “man is not responsible for the extra CO2”.
I would point at that the disagreement lies in three places. The first is that computer climate “feeback” models are bogus.
The second is that the data are inadequate, such as the UHI, the “How Not To” series posted here, fertilized tree rings, etc.
The third is obvious scientific malfeasance, such as the “Hockey Stick” affair, GISS “normalized” temperatures, and so on.

Cassanders
February 26, 2009 12:09 am

Kudos
It is useful to have clarifications on this theme, and I will store this for later revisits.
Just a minor quiggle in a hurry.
When stating your fundamental desciption of the earth as a thermodynamic unit, you do (correctly) include heat content (or eventually changes in ocean heat content).
But my old and battered brain vaguely remembers that borehole reconstructions of temperature was fairly prominent a number of years ago.
I assume borhole reconstruction of temperature is based on models wehre rock also have thermal heat content?
Bur regardless borehole reconstructions: Does not earth (rocks + soil) have heat content (with thermal inertia ) as well?
I assume it should be closer to the properties of water than atosphere.
Cassanders
In Cod we trust

Scott Gibson
February 26, 2009 12:15 am

@Richard111
Heating the air doesn’t reduce the water content, it just reduces the relative humidity, which is a measure of moisture content compared to the dewpoint of the air at that temperature. That also explains why rising air forms clouds; as air with a certain moisture content rises, it cools to its dewpoint, and water condenses into droplets. See an article in Wikipedia for a graph showing the relationship between the dewpoint and temperature.

Scott Gibson
February 26, 2009 12:19 am

Oops, clarification: relative humidity is a measure of actual moisture content compared to the amount of moisture that can be contained at the dewpoint.

Fredrik Malmqvist
February 26, 2009 12:30 am

Note that CO2 doesn’t heat but rather act as a ”radiation blanket” . Nils Bohr showed that gas molecules that absorb light are exited to a energy level and can only give off this energy with light at the same wavelength. This light can go in any direction. Some will again hit earth and create heat. Before Bohr it was believed that gas was heated by absorbed radiation.
This effect is called “greenhouse effect” in the debate. A greenhouse is however heated because the glass stops air convection. A greenhouse build with glass transparent to all wavelength would be as good as one built with window glass. This was also shown early last century (by a physicists named Wood).

Jerry
February 26, 2009 12:33 am

I very much doubt that increases in atmospheric temperature cause the oceans to warm up to any significant extent, given the vastly greater thermal mass of water compared to air. Since about 72% of the Earth’s surface is water, which shows as black on IR photographs and is therefore absorbing everthing, it is fairly obvious that the oceans warm the atmosphere. We in the UK know this very well, as the North Atlantic Drift stops us having the climate of Newfoundland.
All the theorising is fine, but before going public with the results of models you have to show that the undoubtedly correct theoretical basis for some individual parts of an immensely complex real system extends to all parts of that system. In particular, if you want me to believe your predictions you must be able to show, reliably, that any model run will always reflect accurately the state of the climate at any time over known history. You are a very long way from even approaching that.

Lindsay H
February 26, 2009 12:35 am

As Dr. Hansen has correctly argued, increases in atmospheric temperature cause the ocean to warm up.
really!
I have seen no proof of this, the average ocean temperature is about 4-5 deg c
90 % of the ocean is below the thermocline with a temperature of about 3 deg c
hardly a heat sink more like a cold sink, the surface temperature varies from -5 to + 30 deg c but its effect on the average ocean temperature is small.
The climate sensativity to co2 doubling is the issue, no one disputes the absorption effect at 650 wave no, but there is dispute about the effect in the upper atmosphere.
If there was no co2 in the atmosphere what would be the temperature using the IPCC models?
an ice age ? it wouldn’t happen : The models are flawed. The average temperature might drop 2 degrees ?
Isn’t water vapor responsible for 95% of absorption, thus maintaining the planets temperature in a +- 5degree range, from ice age to ice age !

tmtisfree
February 26, 2009 12:37 am

“It has been known for a long time that even a short column of air contains enough CO2 to saturate LW absorption. This has been misinterpreted by some skeptics to mean that adding more CO2 will not increase the temperature. That is simply not true, as higher GHG densities force the temperature up.”
The 2 last sentences contradict physical laws. Reasoning only with CO²:
1/ As you said, all LW radiations are exciting a small and finite number of CO² molecules within the first meters (<10m) above the surface. That means adding more CO² molecules will not increase this finite number of excited molecules. Thus the number of excited molecules depends exclusively on the solar irradiation.
2/ Calculation and comparison of the frequencies (which can be interpreted as probabilities of occurrence) of
a) decay rate (natural broadening),
b) relative molecular movement (Doppler broadening) and of
c) molecular collision (collisionnal broadening)
show that the frequency of molecular collision is at least 4 orders of magnitude higher than the frequency of decay rate. That means that through molecular collisions and de-excitation as kinetic energy (heat measured with a thermometer), system reaches rapidly to a pseudo thermal equilibrium.
3/ The calculation of the velocity distribution in such system shows that only a very tiny part of the CO² molecules will keep enough energy to re-emit a photon with an energy corresponding to a 2.10^13 Hz frequency (or a 15 µm wavelength) to re-excite an other (CO²/H²O) molecule. The tiny part which re-radiates does so 50% upwards and 50% downwards, but as the number of non excited CO² molecules is far more higher (ie molecular system is far from being saturated), the downwards re-radiation is rapidly trapped again by CO² (or H²O) and re-thermalized by molecular collision as kinetic energy. Thus re-radiation in this frequency range plays only a very small part in the energy “trapping” process. Adding more CO² molecules just increases the probability that radiations from the surface excite CO² molecules at a lower height of the atmospheric column.
4/ Consequently, any radiation outside this frequency range will be (except for macroscopic aerosols which will absorb and re-radiate as a blackbody) transparently returned in part to earth (slightly warming it) and in part to the upper atmosphere (and thus slightly cooling it). This is this tiny re-radiation that is thought to be the GH effect accounted for the GW. Quantitatively, the total number of these low frequency photons depends only on the total number of the photons radiated by the surface, and thus only on the solar irradiation. Thus adding more CO² molecules will not change the total number of low frequency re-radiated photon towards surface, that is to say the slight warming which results of will not be modified when doubling (or more) the number of CO² molecules. As the atmosphere is transparent for these downwards photons, their number will also be independent of the height at which CO² molecules have been excited.
5/ So, what do an increase of CO² level?
As the number of CO² molecules increases, the probability that a finite number of CO² molecules is excited tends also to increase at the same height. But as almost the totality of the radiation from the surface is “trapped” within the first meters above the surface, it will not modify the total number of exited CO² molecules and have thus no effect on the total number of low frequency re-radiations towards the surface (GH effect). And because atmosphere is transparent to them, the height at which this process occurs will have no effect on the total number of this re-radiation returned to the surface.
The slight warming is therefore independent of
a) the number of CO² molecules (at the current level),
b) the height at which CO² molecules have been excited.
and is dependent only of
c) the solar irradiation.
I hope the above, which is not true for very low level of CO² (or any GH gases), makes sense.
Bye,
TMTisFree

tmtisfree
February 26, 2009 12:39 am

As an analogy, if you use a blind over a window on a sunny day, adding more blinds will not make the room any darker.
Bye,
TMTisFree

par5
February 26, 2009 12:54 am

Is all of this CO2 at ground level? Thermodynamics aside, how does CO2 force heat back to the surface of the earth? Include thermodynamics, how can there be an energy budget or a heat budget for the earth? I am neither pro or con AGW, more interested in the science…

tmtisfree
February 26, 2009 1:01 am

I forgot the main conclusion.
As the slight warming is already accounted for when temperature is measured, consequently, and given the above, the current temperature can not increase with an increase of CO² level.
Bye,
TMTisFree

Carl XVI Gustav
February 26, 2009 1:03 am

“Its’ amosphere” indeed. Your Nobel is cancelled!

Flanagan
February 26, 2009 1:09 am

Hi Steven,
I also really appreciate your effort and honesty in the process. I simply hope now that the scientific basis we’re sure of will not be endlessly disputed – continuously re-inventing the wheel is such a stupid loss of time, energy and money.
So I suppose the “big” questions you are disputing is whether the warming we are observing is due to the increase of CO2 or not, and if yes whether it is caused by human activities, am I right?

coaldust
February 26, 2009 1:12 am

David Corcoran (23:08:26) :
The argument [is] whether Catastrophic Anthropogenic Global Warming (CAGW) will engender a runaway greenhouse effect that will turn our planet into a mirror of Venus in no time at all, geologically speaking.
This is incorrect. The argument is about feedbacks, but not runaway feedback. There will clearly be no runaway feedback since CO2 has been much higher in the past, and runaway feedback that would “turn our planet into a mirror of Venus” did not occur.

John F. Hultquist
February 26, 2009 1:30 am

Scott,
That should be “relative humidity is a measure of actual H2O(gas) content compared to the maximum of H2O(gas) that can be “contained” at the temperature. The “contained” makes the atmosphere sound like a sponge, which it is not. That’s bad science, as shown in these pages:
http://fraser.cc/ follow prompts teaching, sci., met.,
and: http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html

February 26, 2009 1:37 am

[snip- this comment is pointless and off color]

fred
February 26, 2009 1:37 am

It is frequently argued that AGW is ‘just 200 year old physics’, and this helpfully makes clear why this is not true and is in fact willfully misleading.
It is simple physics that CO2 absorbs heat, and that a gas with more CO2 warms up more than the same one with less CO2. However, what happens next is a different, independent, and more complicated question, and is about feedbacks. The atmosphere is a system, not a gas. So it is perfectly possible that the figure of 1.2C for a doubling of CO2 could be right, but that the net effect of that doubling could be zero, 1.2C or much greater. It depends how the rest of the system reacts over time to the initial rise.
It is a bit like the argument that a given car will travel 40 miles on a gallon of gas is simple physics, and comes from the energy content of the gas, which is not subject to dispute. It is true that the energy content is not subject to dispute, but how far it takes a car of this particular design may be physics, but it is not simple physics, and is not primarily determined by the energy content of the gas. The key question about the climate is whether clouds are negative or positive feedbacks. Do clouds and rain and other atmospheric phenomena amplify smallish warmings from whatever cause, or do they lessen them?
This is connected to the argument about the MWP and RWP. If we can point to previous warmings followed by coolings which were not caused by CO2, it must be more plausible that there is something which can produce cooling in response to warming. So it must be plausible there is some form of negative feedback in the climate system.
The hard thing for AGW to explain, given the hypothesis it is obliged to make about climate sensitivity and feedback, is why cooling followed the MWP and RWP. This on the face of it is inexplicable if they are right about climate sensitivity and the direction of feedback.

February 26, 2009 1:41 am

I have a problem with the suggestion that a slightly warmer air could warm the oceans on a timescale that need cause any concern.
A warmer air increases the temperature differential between air and space and so could well accelerate energy loss to space before any significant effect on the oceans could occur.
I also see difficulties with the proposed ocean skin effect which has been put forward by AGW supporters to overcome the ocean warming problem but which has not yet been proved to be effective in the real world.

February 26, 2009 1:51 am

The saturation issue and the density issue should be treated seperately in relation to a single GHG.
It is quite true that a level of approximate saturation can be reached for any single GHG but for a planetary atmosphere as a whole the total density arising from all it’s constituents is the paramount factor.
In the case of CO2 on Earth such saturation is reached well before any increase in the quantity of CO2 could have a significant effect on total density because the proportion of CO2 is so small.

Malcolm
February 26, 2009 1:57 am

I’m sorry Steve but as TMTisFree has shown the GH effect IS still poorly understood. There are a finite number of radiant particles involved in the GH effect on this planet, simply adding more GH gasses into the atmosphere does not neccessarily equate to higher temperatures. That is what the temperature record is telling us.

John Finn
February 26, 2009 2:03 am

As Dr. Hansen has correctly argued, increases in atmospheric temperature cause the ocean to warm up.
Is that what Dr Hansen has argued? His main point seems to be that ‘missing heat’, i.e. heat not yet evident in the atmosphere is atually accumulating in the oceans. I’d like to see the argument behind this since thermal emission from the atmosphere can only penetrate a few micron into the ocean ‘skin’.

lgl
February 26, 2009 2:08 am

And what happened to the LW backradiation to the surface?

Nylo
February 26, 2009 2:19 am

With “saturated”, I have always understood that all of the energy at a given wavelength that is emitted is absorbed.
The Earth is a microwave oven and CO2 is food in it. If the effect is saturated, it means all the energy provided by the microwave (i.e. Earth emissions at the right wave length) will be absorbed by the food (CO2). When we have little food, the food will get very hot. However, as it is little food (low concentration of CO2 in the atmosphere), its total heat content or the total heat content inside the microwave will not be very big. When we have a lot of food (high concentration of CO2 in the atmosphere), it won’t get very hot but, as the concentration is greater, it will have a similar effect in the overall atmospheric temperature (heat content inside the microwave). Similar? I would rather say “exactly the same”.
If a higher concentration of molecules capable of absorbing the energy had any effect in an already saturated effect, we all would put huge plates full of food in the microwave. But this is not true. We know that if we put twice as much food, we need twice as much energy to make it reach the same temperature.

Julian Flood
February 26, 2009 2:21 am

Learn about feedbacks indeed. 30% of the ocean is covered by strato-cumulus cloud, albedo about 60, while the open ocean is albedo effectively zero. How anthropic changes alter that thin cloud layer will have massive changes on the average albedo of the Earth, more than enough to change the temps.
If you look at Tinsdale’s graphs of maritime air temps you will observe an abrupt rise in temperature from 1939 to about 1943 (this effect is smeared out in the Hadley SST graphs as they’ve added a ‘correction’ which looks dubious to me) and I have postulated that the oil-spills from the Battle for the Atlantic reduced CCN numbers, lowered reflectivity during day and emmisivity by night, hence warming the upper levels of the sea. The Kriegesmarine effect is about oil, but you get the same result from surfactant. We cover the entire ocean surface every two weeks with a thin layer of pollution — you can even see it when an ice-floe melts, an oily smoothness all around the ice. That’s probably caused by phytoplankton, but I’d not be too surprised if it turns out to be caused by stuff entrained in the ice from the atmosphere over a few years.
Nozieres is researching bacterial surfactant effects on clouds. VOCALs is looking at strato-cu off the coast of Chile. I hope they’re checking the cloud particles for oil and surfactant pollution. If they find it them you read it here first: if not, please forget I said anything!
The science of feedbacks is extremely poor — this is where I draw the line when I hear the chant ‘the science is settled’. Until cloud feedbacks are intensively researched, all the hooha is just hand-waving.
JF

Ed Zuiderwijk
February 26, 2009 2:28 am

The figure shown is for summer at mid lattitudes. But it’s the winters that have become warmer between 1970 and 2000, not the summers. So I’d like to see the same diagram for winter conditions to see what the difference is.

warm puddle
February 26, 2009 2:32 am

Thanks for the post, it is certainly an issue that needs clearing up. I am wandering what literature the explanation of the greenhouse effect is based on. Is this essentially still based on the work of Arrhenius that was never validated? (Arrhenius, 1896).
I think your explanation can be best explained using hydraulics. co2 acts like rocks piled across a river, the temperature grade acts like the hydraulic grade. As the water slows to flow through the rock, water heads up behind due to the restriction, however adding more rocks past a certain point wouldnt increase the heading up of flow once it had reached equilibrium, only the first section of rock would really determine the depth (equivelent to trapped heat at the surface) and no flow would be sent backwards due to the net energy flow being downhill. Would this be a fair explanation?
I have read several papers that claim a chamber filled with co2 becomes no warmer in the sun than one with normal air, the same applies for tests using glass and polished rock saltcrystals . Doesnt the hypothesis then fail testing?
What are your thoughts on the following papers i.e. that convection is the main factor in the GE or that atmospheric mass determines the GE? http://www.ingentaconnect.com/content/mscp/ene/2003/00000014/F0020002/art00011 or http://www.springerlink.com/content/t341350850360302/?p=eaccc84960854cb0baba8d1d3860ac53&pi=2 (also see their response to the rebuttal) also http://xxx.lanl.gov/abs/0707.1161 claims to falsify the GE.
I think the practical testing issue needs to be resolved as does the contradiction of the second law of thermo dynamics beforfe I take the GE as rock solid theory.

Mark N
February 26, 2009 2:36 am

@John F. Hultquist
Thanks for interesting links

Nylo
February 26, 2009 2:50 am

If the effect is saturated, it means that no single 600/cm photon escapes the Earth. Then what happens to them?
A photon emitted by the Earth surface is quickly trapped by a CO2 molecule. The molecule increases its energy, or vibratory state. The most likely next thing is that the molecule emits back another photon of the same wavelength and reduces its energy, as a good absorber is a good emitter. If this happens, the new photon will be trapped by another CO2 molecule, as none can escape the earth at that wavelength: the effect is saturated. So nothing really happens: a molecule reduced its energy but another one increased it. However, the CO2 molecule can also reduce its energy by collisions with other molecules of a different kind, “passing” to them the vibratory state. Those molecules will in the end emit photons to release energy, but will do it at different wavelengths which are not saturated, and the energy escapes. In a stable situation, the ammount of energy emitted by the Earth Surface at 600/cm will be the same energy that CO2 molecules pass to other molecules by means of collisions and utterly escape the Earth at a different wavelength. In the tame it takes for the conversion to happen, CO2 molecules have an increased energy and this raises the overall atmospheric temperature.
What happens if we suddenly increase the concentration of CO2 molecules in the atmosphere? We have the same number of 600/cm photons at the origin, the Earth Surface. What happens is that each CO2 molecule traps less photons. There will be more molecules trapping energy, but each of them will trap less energy. There are more CO2 molecules but each of them has less energy than they used to, so the atmospheric temperature shouldn’t change yet. What we need to know is how this affects the speed at which heat or energy is transferred to molecules of a different kind so that the energy can be finally radiated to space. If each CO2 molecule traps less energy, they vibrate less and transfer less energy through collisions with other molecules. But at the same time, we have more molecules doing the same thing. What is more important? In which way do we transfer more energy through collisions? Is it with a few molecules colliding a lot or with a lot of molecules colliding less? For me, that is not clear at all. How is the process of finally transforming the wavelenght of the 600/cm photon faster, with a lot of CO2 or with little CO2? Do we have more 600/cm photons trapped in the atmosphere at a given time with a lot of not very energetic CO2 or with little but very energetic CO2?

Allan M
February 26, 2009 3:10 am

“Steven Goddard (23:39:50) :
Molon,
What you are not considering is that LW is absorbed and emitted many times on it’s tortuous path out of the atmosphere. The more GHG, the more times it is absorbed.
Your argument is analagous to saying that one stop light has the same effect on your commute time as does 100 stop lights.”
This is all the SAME heat, it doesn’t matter how many times it is absorbed and re-emitted. If absorption heats, then emission cools.
You cannot have your perpetual motion machine!
And, IMHO, the analogy stinks! (As most analogies do; stick to explanation.)
AM

Sandy
February 26, 2009 3:14 am

If we are heat balancing the Earth we need to know the rate of transfer of the heat from the magma through the crust. It would be a brave man who estimates the total nuclear fission power of the earth’s core and braver still to claim that it may be considered as being released uniformly over the globe.

par5
February 26, 2009 3:24 am

I have a problem with the first graph- it implies a ‘budget’. If watt/in equals watt/out, then hotter days equal colder nights. Then, the mean temp would not change but remain a constant? I understand the chemistry because it’s so easy and provable (never met a theoretical chemist), but I’m still having trouble with the physics. This is just one of the reasons that I am still a ‘fence sitter’ on this subject. I will admit to being slightly skeptical, but that is just a personal trait. There are just so many different opinions from well respected scientists on both sides, and it isn’t nice or fair to beat up on them. Anthony- great site! Sending you a donation immediately. Enjoy your day…

Johnny Honda
February 26, 2009 3:27 am

Steve,
this is the first articel und WUWT that is disappointing for me. It is not a correct description of the situation.
Most important fact: Until now, there is NO physical correct description or definition of the greenhouse effect.

“outgoing radiation = incoming radiation – changes in oceanic heat content”

Wrong, you forget the latent heat of the water dampening out from the land (land ist mostly not total dry).
You forget the heat loss by convection (wind is blowing along the earth surface and is heated up).
The latter is important! Wind is heated up at the surface of the earth, is warmed by this, is rising, and is emitting (by GHG!) heat to the space and so is cooling. With this mechanism we have cooling by Greenhouse-Gases!

“If there were no greenhouse gases in the atmosphere, earth would be a cold place”
“The other 50% reaches the earth’s surface and warms us”

OK, if we have no greenhouse gases (no water, no CO2), almost 100% of the radiation reaches the surface (no clouds! amost no absorption!)), so it will be colder on the planet??
Why is the day temperature on the moon ca. 160 °C ? No Greenhouse gases!
Another mechanism: Water vapor is rising, it condenses, and the heat is emitted (to a large extent) to space! When the water is evaporating at the sea or landsurface, heat is taken away from the surface. Result of the process: The surface is cooled by the GHG water!
Please read the work of Prof. Gerhard Gerlich! It is essential for the understanding of the situation. Why you don’t ask him for a guest article? His E-Mail: g.gerlich@tu-bs.de

tmtisfree
February 26, 2009 3:30 am

lgl (02:08:56) :
And what happened to the LW backradiation to the surface?
It simply warms slightly the surface. It is not sure if it is possible to experimentally discriminate this ‘indirect’ heat. But it is possible (and complicated) to calculate the probability of occurrence of this LW re-radiation and thus estimate the small theoretical heat added to the surface. Anyway, because atmosphere is transparent for this LW re-radiation, this slight warm is already accounted for when measuring temperature.
Bye,
TMTisFree

weatherag
February 26, 2009 4:02 am

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.
As a skeptic and a Meteorologist, several of my friends, co-workers and I don’t deny that the greenhouse effect does not exist. We all acknowledge that the greenhouse is important. CO2 is need for plant grow and respiration. My argument is that the computer models are taken as fact. I have used computer models to make weather forecast for years. I know from experience that the models are not reality and that they frequently wrong. They are tools used to help make an educated guess as to what the weather will do the next few days. Now, I know that weather is not climate, but the principle behind the models still stands with the climate models. They use the same equations as the forecast models. Climate scientists, who claim the 6C increase temperature from the model as fact, should consider getting more forecast experience.
Dr. Hanson argument that heating the atmosphere will heat the ocean is wrong. You have to ask yourself, how you boil water. You don’t blow hot air over the surface; you heat the water from below. The atmosphere can’t be totally responsible for the increase in SST; it might increase the temperature in the first few inches of the surface, but not the entire water column. The oceans are heated by incoming solar radiation and from underwater volcanoes.
Our climate and weather are very complex systems that have several different mechanisms working together and against each other to balance the incoming and outgoing heat. Changing a very small amount of trace gas is not going to produce a very large temperature increase. You have to consider solar constant, ocean currents and SST, atmospheric circulation and the distribution of the gases throughout the atmosphere. I do agree that an increase in CO2 will increase temperature, but not to the extent that some models and other scientist suggest.

Tomcat
February 26, 2009 4:03 am

“If you want to make a knowledgeable argument, learn about the feedbacks. That is where the disagreement lies.”
I think the disagreement lies in how well are computer models at predicting that a warmer future is bad. CO2 levels have been above 1000 PPM for the vast majority of the billion+ year history of life on Earth.
Thanks,
Tomcat

Larry
February 26, 2009 4:04 am

The number of “facts” stated in this “primer” which are, in fact, assertions without basis are mind boggling. One of the most glaring is the assertion that James Hansen’s “correct” statement that the atmosphere heats the ocean is in direct contravention of statements by the late Robert Stevenson, former director of the Scripps Institute and a Climate scientist of over 50 years experience who says categorically, there is no way the atmosphere can heat the ocean!
Another one is the assertion that Antarctica is cold because of a lack of water vapor. In fact the opposite is true. There is a lack of water vapor because it is cold. If there was enough water vapor in the antarctic atmosphere it would form clouds which would block what little sunlight manages to reach it and make it colder.
I find the whole article suspect in its approach.

Frank Lansner
February 26, 2009 4:05 am

Im not convinced that the greenhouse effect is anything but miniscule.
Temperature on the different planets are clearly dependent on the distant to the sun and pressure of a given place in the atmosphere.
For instance, if you go deep enough on Jupiter and Saturn you will find temperatures higher than on Venus surface.
If you just go down to 1 atm pressure in Venus atmosphere you will see that the temperature is just 50-60 Kelvin warmer than earth, quite predictable considdering the shorter distance to the sun.
Also, take a look at Titan (Saturns moon). Titans atmosphere is clearly NOT better isolating than Saturns atmosphere. In fact, Titan is almost as cold at 1,5 atm as Uranus!
The funny thing is, that Saturn is almost 100% pure Hydrogen and Helium, only trace amounts of Greenhouse gasses. But Titan, the cold globe, has no less than 5% Greenhouse gasses! And its not just one greenhouse gas, its Methane, Ethane and many many other substances…
No. Im not convinced at all. H2O in the form of droplets (clouds) like any other types of clouds has micro phase shift between liquid and gas. THIS is effective to back-radiate. The thing is, Droplets Backraiates ALL frequencies, not like for instance CO2 that doesnt back radiate anything. It just changes the direction of heat randomly and only for a specific frequency. The thing is: As long as there is a hole in the bucket, it will not hold anything. CO2 and the greenhouse gasses does not by long shot close the hole in the bucket. Heat with the speed of may be hold back some split seconds before – via earth or otherwise – finding a frequency that the greenhouse gasses does not stop. We are talking split seconds, and thus an inferior impact on temperatures.
Im of course not sure of this, but this makes the best sence to me.

DocMartyn
February 26, 2009 4:14 am

If you put your head in the oven, and your feet in liquid nitrogen, you will on average, have a temperature of 37 degrees.
The Earth rotates, and the surface temperature changes throughout the day.
incoming radiation changes throughout the day.
Outgoing radiation changes throughout the day.
Humidity changes throughout the day.
Air pressure changes throughout the day.
Attempting to impose an equilibrium model on a steady state system is beyond simplistic, it is stupid.
A minimum equilibrium model would slice the day into 24 intervals and examine the quasi-equilibrium and examine the heat influx and efflux into heat reservoirs.
Here is a clue, the Earths surface is >70% water and under goes a phase transition on heating and cooling, as such during an energy input water turns to vapor and, during the night, it turns to a liquid.

February 26, 2009 4:16 am

The equations I have seen for atmospheric physics of doubling CO2 (from 280ppm) seem very simple, and the spread for no feedback is 0.5-1.5C in the published literature. The gain factor added for global modelling of the consequences is usually 3 – and this is the fabled water vapour feedback. Lindzen criticised this in the first IPCC assessment as unproven, and argued it could be zero if the water vapour condensed to cloud. Hence no runaway. Hansen’s models assume the gain factor is 3. These assumptions can be tested by observation. If we look at the tropospheric air temperature – it has risen (with some variability) by 0.5C for a 35% increase in GHG. The latest MSU data shows about 1C anomaly for 2008, and January 2009 maintaining that anomaly. So it would appear the atmosphere is warming as expected.
However, surface temperatures show cooling of .3C for 2007 and 2008.
Surface temperatures are not driven by atmospheric temperature, but by ocean heat content and its transfer to land (Compo & Sardeshmukh, ‘oceanic influences on recent continental warming’ Climate Diagnostics Centre, University of Colorado.)
So the oceans are the key, and as everyone points out, there is very little power in the atmospheric heat content to affect the ocean heat content – it can only happen by lessening the heat gradient and heat loss, but this is dominated not by CO2 but by H2O, and by cloud cover.
The key is clouds. And if we look at all the satellite derived cloud data we see a steady fall in low level reflective clouds from 1983 to 2006 and a rise from 2001 in mid and high level clouds that are probably more insulating than reflecting.
Data at NASA for surface Short Wave flux confirms the cloud thinning – with the anomaly at 4-6 watts/sq metre (average global) persisting for many years in periodic pulses from 1983-2000 (vaguely mirroring the 11-yr solar cycle) and contributing far greater energy than the (computed) CO2 radiative forcing of less than 1 Watt/sq metre (increment over the period).
Thus, the ‘global warming’ of 1980-2005 (a 25 year period), and without which there would be no peripatetic James Hansen, and probably no IPCC either, has clearly been driven by extra SW radiation reaching the earth’s surface due to cloud changes. These changes could be ‘claimed’ as AGW effects, but they are not predicted in the models – which have inadequate cloud components. As we know that ocean basins have low frequency oscillations (e.g. the PDO at 30 years) that are independent of CO2 concentration, but show correlations of solar magnetic cycles, we ought to suspect that the excess SW and cloud changes are part and parcel of the natural ocean cycles. Thus, they have amplified the ‘global warming’ signal, and now they are suppressing it.
However, my nearby Hadley Centre, having become an integral part of the IPCC system, only draws attention to the latter – the power of the cycles to now bring an intermission of global cooling (they don’t call it cycles, however because their models cannot replicate cycles – so they call it natural variability – implying randomness, which is more readily simulated) .
The surface temperature of the oceans is not the best guide to the warming period. As IPCC tell, 84% of the ‘warming’ is held in the oceans as heat content. Oceanographers tell that this heat is trapped in the upper layers down to about 700m, but most is in the first 200m. Interestingly, that ‘upper ocean heat content’ (best phrase to google for data sets) is concentrated in two major zones – the northern pacific and atlantic gyres, whereas the southern oceans tend to dissipate more (John Lyman and NOAA, and Hadley Centre (HADOBS) have maps. These two zones are very sensitive to shifts in cloud cover and these are timed by the respective PDO and its Atlantic equivalents (NAO at 10-20 years, and AMO at 60-100 years), and also interact with the Arctic Oscillation (about 70 years). Incidently, the whole of the Arctic melt-down is explained by the penetration of North Atlantic warm water and excess cloud over the polar ice (14% up between 1980-2000), and the 2008 turning of the trend was predictable once the PDO shifted to its cold phase in 2006/2007. The ice is melted from above by IR radiation from the excess cloud and below by warm North Atlantic water penetrating further north than usual – due to a weakened Beaufort Sea gyre associated with the warm phase of the PDO. With the PDO in cold phase, the ice will come back, as long as the North Atlantic doesn’t get warmer – and it seems to be at the end of its own warm phase.
As we know, the oceans stopped accumulating heat around 2002, at the same time as there was a step change in global cloud cover (measured as percentage increase). However, percentage may not be as important as a spatial shift (e.g. southerly shift of the jetstream). The jetstream is very sensitive to the solar cycle – both due to UV flux and it would seem, the magnetic cycle (though the two are related). During the Little Ice Age there is evidence the jetstream shifted south for some considerable period – as it did in 2007 and 2008 in the current solar low.
If significant cloud banks moved to uncover and expose the main gyres, they will lose heat.
These two ocean heat stores affect the planetary heat budget via teleconnections to other ocean basins – though Antarctica seems insulated and tends to go in the reverse direction to what happens in the northern hemisphere.
There is no direct evidence in the Long Wave data for CO2 build-up effects because the flux is so dominated by LW emissions from clouds (whether upward or downward).
Thus, the only direct evidence for causal drivers of the observed global warming and recent ‘pause’ relates to cloud cover and SW flux, ocean absorption of heat and the remix of ocean heat content. If CO2 contributes, that contribution cannot be greater than 20% (by comparision to the wattage from SW compared to the computed radiative forcing wattage) and as the computed CO2 signal is uncertain, I would say there is a range of 10-20%.
If we assume the world emission control programme halves current emissions by 2050 (very unlikely, I know), this will address only 5-10% of the driving force and hence, whatever other benefits might accrue, be ineffective in the stated aim of ‘avoiding climate chaos’.

MattN
February 26, 2009 4:49 am

Stunning. Reasic hasn’t shown up yet to tell you how wrong you are.

MarkW
February 26, 2009 4:52 am

I thought that Mars’ atmospheric pressure was about 1% the earths. And it’s atmosphere was about 100% CO2.
If so, that would give it more CO2 in it’s atmosphere than the earth has.

manse42
February 26, 2009 4:57 am

How much would a drop of boiling water heat my pint of beer?
I posted earlier

Isn’t the enthalpy and specific heat capacity somehow missing?
The potential heat content of the entire atmosphere above 10mb is less than 1/100 of the potential heat content below 10 mb.
And it is above 10 mb where the big CO2 effect is, as I read the chart…

Or is the difference of potential heat content of no importance?

Simon Evans
February 26, 2009 5:02 am

Steven – thank you for such a full answer. I agree with you entirely that climate sensitivity is the most significant area of discussion.

Johnny Honda
February 26, 2009 5:04 am

“outgoing radiation = incoming radiation – changes in oceanic heat content”
Oh, OK, I saw that you made a balance at the edge of the amtosphere. But the mechanisms that I described are correct (I hope)
And what happened to the LW backradiation to the surface?
It simply warms slightly the surface

Nooo! We must obey the rules of thermodynamics, like Homer. So also the second rule, i.e. no colder matter (atmosphere) can warm a warmer matter (earth).
Correct: The LW backradiation is lessening the net radiation of the surface

Hasse@Norway
February 26, 2009 5:04 am

Hmm, I don’t understand how CO2 radiation is going to heat the oceans considering the IR radiation is absorbed within the first 1-2 mm. Add to that the weight of the atmosphere of only 0.389% of the oceans and that only 380ppm of those 0.389% are CO2. I don’t see how that should be possible in any shorter therm period or at all…

February 26, 2009 5:09 am

OT – Sorry Guys
Federal US Budget calls for Carbon Cap and Trade as a part of Obama’s cut the deficit in half pledge by end of first term.
“Another official said the budget included hundreds of billions of dollars in revenues, starting in 2012 and going over many years, from a greenhouse gas emissions trading system, one of Obama’s key proposals to fight global warming.”
See my site for more Info and read my Dangers of Implementing Cap and Trade in a Recession post

February 26, 2009 5:15 am

Tell me where I am wrong…
Energy arrives at the earth in units (a rose by all your other names is confusing)
This energy (neither created nor destroyed, but changing forms) hangs around for a while, then makes it’s exit into the vastness of space.
If this unit of energy (and all its companions) hangs around for a longer time, Earth gets warmer. If it exits sooner Earth gets cooler.
This is slightly complicated by the fact that the Earth generates some of its own energy. (for those who care, measured in milliwatts per meter squared) And, the number of units, in coming, changes for various (and in some cases unknown and unmeasured) reasons.
Then calculating global warming/cooling is a simple calculation in probability: What is the probability a unit of energy will hang around for a while. High probability=warming, low probability=cooling.
The unit of energy strikes a molecule and is reflected or absorbed (and changes form). It is retained or changes form again as it is sent on its merry way. The unit of energy then strikes another molecule and is reflected or absorbed. It is retained or changes form again as it is sent on its merry way, again. Etc.
How hard can this be? A little physics, a little chemistry, a little probability and a huge computer…

Mary Hinge
February 26, 2009 5:17 am

Steven Goddard (23:39:50) :
What you are not considering is that LW is absorbed and emitted many times on it’s tortuous path out of the atmosphere. The more GHG, the more times it is absorbed.

A good point often missed. Isn’t it also true that each time the LW is absorbed and emitted the wave length increases, indeed isn’t this true of all electromagnetic radiation?

February 26, 2009 5:18 am

Steve
I take strong exception to your statement, “There is no dispute about this in the scientific community” when, from what I see, that there is some very strong dispute about this whole subject of AGW. If you are not able to acknowledge this plain fact, why should we give credence to anything else you say?
Also, Venus is hot because it is so close to the sun. Stand near to the fireplace and you’ll understand.

Allen63
February 26, 2009 5:20 am

Yes, the greenhouse effect of CO2 is real. And, CO2 seems to be rising along with temperature. That’s why Anthropogenic Global Warming is a “plausible” hypothesis — and worth studying.
Thing is, AGW via greenhouse effects as a significant factor in Earth’s climate is an “unproven” hypothesis. Moreover, even if AGW takes place, genuinely catastrophic AGW seems “implausible” as one digs deeper into all the aspects (assuming humankind can adapt to a few feet of sea level rise and substantially improved global food production).

Steven Goddard
February 26, 2009 5:23 am

Good questions coming in.
Remember that,heat is not trapped. If it were trapped, the earth would be incredibly hot. The energy remains in balance, as Homer clearly stated.
The article does mention convection, and re-radiation is equally likely in any direction (including downwards.) That is why a cloudy nights are warmer.
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.

jae
February 26, 2009 5:23 am

Steven Goddard:
“Temperatures are very sensitive to H2O levels, particularly at night. Which is why deserts get cold at night. H2O is the most important greenhouse gas.”
This is a myth. It is true only for high-altitude deserts. The night-time temperatures in Phoenix in the summer are WARMER than they are in the South at the same latitude. For example, the average minimum July temp. in Phoenix is 27.2 C; whereas in Birmingham, AB and Atlanta, GA the average July minimum is 20.8 (30-year averages).

jae
February 26, 2009 5:30 am

BTW, please explain to me why it gets so much hotter in deserts than in humid areas at the same elevation and latitude, if the greenhouse effect works as shown here. As noted, water is the most important greenhouse gas, and there is about 3-4 times as much of it in humid areas than in deserts. Also, explain why it almost never gets over 33 C in the humid tropics (where water vapor levels are always 4 times those in deserts); whereas 50 C is very common in deserts. Negative feedback by water is a fair explanation, IMHO.

Editor
February 26, 2009 5:39 am

Steven Goddard (23:35:29) :

Mark N,
Temperatures are very sensitive to H2O levels, particularly at night. Which is why deserts get cold at night. H2O is the most important greenhouse gas.

That’s one of the reasons. One other is that dry soil is a decent insulator so the heat flux to the surface is low. Another is that in humid areas, the heat released by dew formation significantly slows down cooling. Even when dew forms in the desert, there’s so litte water vapor to work with it cooling isn’t impeded as much as in humid areas.
There are some areas in Eastern Oregon where surrounding basalts acted like the urban heat island from hell. It did not get cold at night! With daytime temps over 100F (40C), it was not the most comfortable bicycling. Soaking our jerseys in any water we could find helped a lot though.
BTW, I’ve written a “State of the Climate” report that starts with a very similar graphic as Steven uses at the top of this article, see http://wermenh.com/climate/climate2009.pdf
I’ll make it the link from my name.

jae
February 26, 2009 5:39 am

All the greenhouse gas molecules can do is slow down (a little) the rate at which the energy leaves the atmosphere. They cannot in any way ADD heat; only the Sun can do that. One problem with all the nice little radiation cartoons is that they ignore convection, which counterbalances the slow-down caused by the radiation. It’s much more complicated than shown by the radiation cartoons.
And I’ll bet that water completely overwhelms any small effects by CO2, probably making them negligible.

Steven Goddard
February 26, 2009 5:51 am

Ric,
I did a canoe trip down the Green River in Utah about 25 years ago in July. It was too hot to sleep when you went to bed, and too cold to sleep when you woke up!

John Peter
February 26, 2009 5:52 am

Here is an interesting statement made by William Happer Cyrus Fogg Brackett Professor of Physics Princeton University to U.S. Senate Environment and Public Works Committee Senator Barbara Boxer, Chair on 25 February 2009:
http://nzclimatescience.net/images/PDFs/happer.pdf
At least some parts of the US Congress would appear to be prepared to listen to well reasoned and balanced arguments about the true state of Climate Change research and the role played by CO2.
Maybe this is part of an overall slow moving process resulting from the “braking” of global warming since 1998. Who knows? Time will show.

MattN
February 26, 2009 5:53 am

BTW, excellent post Steve. The strawman argument that all alarmist use is that we (skeptics/deniers/flat-earthers) do not believe adding CO2 increases temperature when the ENTIRE argument is in the feedbacks.

MarkW
February 26, 2009 5:53 am

Allen63 (05:20:14) :
Yes, the greenhouse effect of CO2 is real. And, CO2 seems to be rising along with temperature. That’s why Anthropogenic Global Warming is a “plausible” hypothesis — and worth studying.
————–
During the 60’s and 70’s, temperatures fell, even though CO2 was rising.
Over the last decade, temperatures fell, even though CO2 was rising.

Steven Goddard
February 26, 2009 5:55 am

Note the upwards curve from renowned skeptic Dr. Lindzen in the quadrupling graph above. Skeptical scientists do believe that increasing CO2 increases temperature. Dr. Spencer says the same thing.

Gary Palmgren
February 26, 2009 5:55 am

http://miskolczi.webs.com/
As I understand F. Miskolczi’s theory, he discovered a negative feedback term when the differential equations for radiation transport were solved with the correct finite thickness for the atmosphere. This eliminated a 20° discontinuity between the surface an the bottom of the atmosphere that was present in the old incorrect solution with the infinitely thick atmosphere. This shows the new solutions are correct.
The earth has a infinite supply of green house gases in the form of water in the oceans. The earth underwent a runaway greenhouse effect eons ago due to all this water and the temperature went up until the negative term became important and an equilibrium was reached. The earth has been existing at a balance point ever since.
According to Miskolczi, as we add CO2 to the atmosphere, the balance is maintained by a little water raining out. The optical density of the atmosphere remains constant. The amount of water in the atmosphere has decreased over the last fifty years as CO2 has risen.
http://www.climateaudit.org/phpBB3/viewtopic.php?f=4&t=556
The climate models have a built in positive feedback for CO2 warming because the models assume constant relative humidity. This is wrong by the data (and the theory.) Most important is that a runaway greenhouse effect is impossible.

Allan M
February 26, 2009 5:56 am

Steven Goddard:
“If the atmosphere is warmer over the ocean, then less heat flows out of the ocean into the atmosphere, and the ocean warms up.”
No it doesn’t. If less heat flows out of the ocean, it COOLS LESS.
Also an important effect of warm cloudy night is the reduction of convection by the denser clouds of water vapour ( The REAL greenhouse effect).

Jon H
February 26, 2009 5:58 am

If you only consider CO2, and historical surface data for the last 100 years in a model, then you get a +6C rise.
If you factor in cosmic rays, Earths relative distance from the sun, Suns relative position in the galaxy, Ocean current fluctuation, humidity, etc. You come to an answer of ???
Then you have 90% of surface stations with significant human growth and building development near them, and the data you gather is tainted, and all conclusions based on the data is suspect or outright wrong.
Will the real scientist please stand up!

schnurrp
February 26, 2009 6:02 am

jae
Why are deserts so hot?
The cooling effect of evaporation is key.

Steven Goddard
February 26, 2009 6:05 am

The AER chart does show convection as “sensible heat.”
http://en.wikipedia.org/wiki/Sensible_heat
Sensible heat is potential energy in the form of thermal energy or heat. The thermal body must have a temperature higher than its surroundings (see also latent heat). The thermal energy can be transported via conduction, convection, radiation or by a combination thereof.

February 26, 2009 6:06 am

Ich denke, dass das Umweltbewusstsein langsam besser wird. Außerdem wird die Marktlücke Umweltschutz immer grösser, da ja auch der Bedarf steigt. So nimmt die Entwicklung auch langsam einen positiven Verlauf. Desweiteren sollte man auch die Wirtschaftskriese als Chance sehen, denn wenn alte Strukturen vernichtet werden, werden neue Strukturen wachsen. Wie die Natur so will wenn etwas Neues entsteht kann um weiten besser und moderner sein. Lass die Politik nur machen, die wollen alle nur Ihr Geldwelt retten und nicht unsere Umwelt. In der Politik geht’s nur um Macht und nicht um Idealismus.
Soll kein Spam sein. Ich finde diese Seiten nur interessant.
Hier ist auch ein Tipp für euch zum Posten NEUER Rekord bei Kohlendioxidausstoß Umweltschutz im Bog
Mit nachhaltigem Gruß
Heinz

Jon H
February 26, 2009 6:10 am

weatherag “Dr. Hanson argument that heating the atmosphere will heat the ocean is wrong. You have to ask yourself, how you boil water. You don’t blow hot air over the surface; you heat the water from below.”
Yes and no. It is more efficient to heat from below, warm water rises heating the whole of the basin relatively evenly, but heating from above will also work but slower and less efficient.
The main problem with “heating the ocean” argument I find is time. The oceans volume is so large, and local, or recent environmental change will not be felt for hundreds of years. Much of the oceans liquid volume is in the same “mode” as the little ice age, and not the modern warming period.
Some theories about the little ice age is that the ocean caused us to leave it, more than the sun did. This is yet another area we do not know enough about.
Anyone know of a study about the movement in the magnetic poles and global volcanic activity? The magnetic core moving or changing it’s axis slightly or slightly more cause magma fluctuation resulting in more activity?? and can you localize where the resulting activity will be centralized due to the waves? Have we even gotten a good image of the planets core, it’s shape, etc?
Volcanic activity would also help us predict warming and cooling periods since it is a major cooling factor as well.. Just an idea.

Bill Illis
February 26, 2009 6:16 am

Nice post Steve,
As others have noted, greenhouse theory and the very greenhouse formulae themselves are incomplete because they are missing the “Time” dimension.
There never really is an energy balance between the energy coming and the energy leaving. Time is a crucial element in the system.
341 W / m2 comes in from the Sun for an average 12 hour period and during the next 12 hour period, 170 W / m2 is either reflected back to space or escapes back to space overnight.
How long does additional GHGs delay the time period that those photons of light / EM radiation stay in the Earth system before they escape to space.
The average energy held in the Earth system is only 170 W / m2 or a delay of 12 hours and increased CO2 could only delay that for a period of minutes or one hour at the outside.
As the summer season warms, perhaps an additional 0.5 W /m2 is absorbed per day and then the opposite occurs during the winter season.
As the deep oceans warm up to catch up with surface temps (which can take 800 to 1,500 years) perhaps an additional 0.1 W / m2 is absorbed per day.
Greenhouse theory needs to incorporate the Time element and we are talking about the speed of light and particle physics types of timelines here.
And the physics show that Temperatures are 0.2C to 0.3C per W / m2, not the 0.75C / W / m2 that Hansen like to quote. [that formula alone invalidates global warming theory and even GISS’ Model E incorporates only 0.32C / W / m2 in its hindcast to match the temperature record.]

February 26, 2009 6:22 am

The way that I heard this is that when the insulating effects first became understood, there was an intellectual proposal that a greenhouse could be constructed without the need for glass to make it work. Before this was tried, someone interjected the proposition that without the glass convection would release all of the gas and that it wouldn’t work. So it was never tried. When the unexpected the high temperature of Venus was discovered (it had been thought to be warm and moist like primeval earth) an explanation was needed. 3 scientists (headed by Carl Sagan) were allowed to propose that this constituted a “Runaway Greeen House effect”. Venus is hotter at its north pole than elsewhere and radiates more heat than it receives from the sun. No one knows WHY Venus is so hot. It has no glass shell around it and neither does earth.
“Science” comes from the Latin scio “I Know”–scientists only WISH that they knew–but want to convince others that they actually do.

george h.
February 26, 2009 6:22 am

Steve,
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. Don’t claim to be expert here. This is not my field.

jae
February 26, 2009 6:30 am

Also, the “ocean effect” is pure heat storage (as is some of the atmospheric effect), and has very little to do with ghgs. Water is quite transparent to visible light, so the energy does get “trapped” by the water. Another BIG reason you cannot compare Venus and Mars to Earth. I think that most of the so-called “greenhouse effect” is simply a heat storage effect. The IR radiation is the “result” of this, not any “cause.” LTE requires that the 98% of the atmosphere that doesn’t absorb/radiate IR must be thermalized. This represents stored kinetic and potential energy. Too many folks are overly-hung up on radiation cartoons.

Mark
February 26, 2009 6:36 am

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?

Peter
February 26, 2009 6:36 am

I hold no scientific credentials so my apologies if my questions seem overly simple.
I’ve been led to understand that the CO2 released by man-made activities represents about 3% of the atmospheric CO2. Can anyone attest to the accuracy of that claim?
Is there something different about man-made CO2 that gives that 3% more impact in Steve’s model?
Thanks,
Peter

Edward
February 26, 2009 6:39 am

tmtis free 00:39:45
You stated earlier: “As an analogy, if you use a blind over a window on a sunny day, adding more blinds will not make the room any darker”
I like your analogy, however I partially disagree and suggest an improvement . Think of the gases in the atmosphere as if the “shade” was cut into narrow strips. Pulling these strips down individually would block particular segments of the incoming light. The more strips you brought down the darker the room would become. Some strips would overlap while others would still allow light into the room through gaps between each other. To completely block light from coming into the room you would need to add multiple layers of shading to eliminate all of these “gaps”.
Thanks
Edward

schnurrp
February 26, 2009 6:41 am

Here is an interesting site. The author attempts to determine an upper level for global warming caused by co2 by simply observing the warming for the 20th century, assuming it was all caused by co2 increase, and projecting additional warming into the future using log functions. Since forcings are ignored as a cause they are “in” the future calculations of an upper limit.

Malcolm
February 26, 2009 6:56 am

I’m sorry, I have read this primer several times but it doesn’t work for me.
The basic problem I have is that in the real world heat is not trapped in the atmosphere, it escapes, and as a result you cannot transfer heat from a colder atmosphere to a warmer surface without the application of work. Where is the AGW engine that heats up the planet?

Phil.
February 26, 2009 6:57 am

The image below shows GHG absorption by altitude and wavenumber. As you can see, there is a strong absorption band of CO2 at 600/cm. That is what makes CO2 an important greenhouse gas.
This is incorrect, the Clough & Iacono graph is of Radiational cooling, i.e. emission.

Steven Goddard
February 26, 2009 6:58 am

jae,
Phoenix is an urban heat island. I’ve driven south on I-10 out of Phoenix in the summer when the temperature dropped 20 degrees between Tempe and McCormick Ranch. That was before McCormick Ranch was part of the UHI. Southern Arizona also gets very high humidities in July and August. I remember once when the dew point was 80F after a thunderstorm.

February 26, 2009 6:58 am

I have read all of the earlier posts on this thread.
Would someone please explain to me how the absorption of carbon dioxide in the oceans is affected by
1) ocean surface temperature;
2) ocean saturation;
3) incident light levels (cloudy or not);
4) microorganism carbon dioxide uptake (plants in the ocean) as a function of carbon dioxide level, salinity, pollution, and other factors;
5) quantity of carbon dioxide currently sequestered in the ocean and in subsea deposits;
6) atmospheric (surface) concentration of carbon dioxide;
7) other ocean/air boundary effects?
What should be glaringly obvious is that we are not well-informed on the overall (intake versus output) carbon dioxide budget. I have not mentioned volcanic activity: how do you assess the contributions of volcanoes to atmospheric carbon dioxide?
The Elephant in the Room is the widely known and equally widely ignored propensity of all plant life to use carbon dioxide in metabolism.
AGW proponents propose a positive feedback phenomenon.
What if the feedback is negative and self-correcting?

John Galt
February 26, 2009 7:01 am

jae (05:23:16) :
Steven Goddard:
“Temperatures are very sensitive to H2O levels, particularly at night. Which is why deserts get cold at night. H2O is the most important greenhouse gas.”
This is a myth. It is true only for high-altitude deserts. The night-time temperatures in Phoenix in the summer are WARMER than they are in the South at the same latitude. For example, the average minimum July temp. in Phoenix is 27.2 C; whereas in Birmingham, AB and Atlanta, GA the average July minimum is 20.8 (30-year averages).

You are describing the Urban Heat Island effect (UHI).
I lived in Las Vegas for a few years. The microclimate in the Las Vegas valley differs from that of the surrounding desert. The relative humidity in the valley is much higher because of all the non-native plants, swimming pools, outdoor watering, etc., etc., that occurs in the metro area.
The urban heat island effect is primarily caused by all the concrete and asphalt which retain heat and electric motors, internal combustion engines and air conditioning exhaust which produce heat.
Your comparisons to other cities with the same latitude as Phoenix are also incorrect. Atlanta is not in a desert and does not have the same day-time highs as Phoenix.

Deanster
February 26, 2009 7:04 am

Steve …
As I understand it, much of the LW energy absorbed by CO2 is transformed in the collision process to different wavelengths. Thus, the LW energy at 600 cm will not remain a constant, but will degrade over distance, and as such, the re-emittance will not necessarily be in a band relevant to further concentrations of CO2.
Thoughts??

gary gulrud
February 26, 2009 7:18 am

“The other 50% reaches the earth’s surface and warms us.”
Where does this 341 W/m^2 come from? We are constantly told 1360 is the value.
“As Dr. Hansen has correctly argued, increases in atmospheric temperature cause the ocean to warm up.”
Help me out. By raising the temp of precip and by increased KE in conduction? What is the consequence of increased temp over 70% of the surface?

Hank
February 26, 2009 7:18 am

Two quick questions
1. Does increased CO2 also decrease the LW radiation coming from the sun from reaching the surface?
2. Does radiation absorbed at a particular frequency by a greenhouse gas get converted to heat (meaning vibrational motion at the molecular level), get reradiated or a combination of the two?

David L. Hagen
February 26, 2009 7:22 am

Fails due to omissions
Steve Goddard
Compliments on an impressive tutorial on conventional wisdom and your efforts to support it.
Unfortunately it fails due to all the major parameters that it leaves out. For starters consider:
1) Differing Reflection Feedback
The Cloud reflection feedback differs between short and long wave radiation.
See: Roy Spencer What About the Clouds, Andy?
2) Cosmic ray variations modulate clouds
See discussion about Svensmark
Center for Sun-Climate Research
“Cosmic rays” And “cosmoclimatology”
See efforts by:
Nir Shaviv

Shaviv, N. J. (2008), Using the oceans as a calorimeter to quantify the solar radiative forcing, J. Geophys. Res., 113, A11101, doi:10.1029/2007JA012989.

We find that the total radiative forcing associated with solar cycles variations is about 5 to 7 times larger than just those associated with the TSI variations, thus implying the necessary existence of an amplification mechanism, although without pointing to which one.

3) Feedback Causation
Spencer & Braswell point to a critical flaw of causation in feedback analysis.
Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration
Roy W. Spencer and William D. Braswell, Journal of Climate, Volume 21, Issue 21 (November 2008)pp. 5624–5628
3) Convection
The temperature in the troposphere is dominated by convection with a strong change in the temperature lapse rate with altitude above and below the tropospause.
As kevendick noted, Miskolczi is a world expert on radiation modeling. He has developed alternative climate theory to explain the major errors in IPCC models not fitting the temperature lapse rate data.
<a href=”http://www.landshape.org/dokuwiki/doku.php?id=introductionThe new climate theory of Dr. Ferenc Miskolczi
See also discussion on Miskolczi
at Niche Modeling
4) Precipitation
The Prof. Emeritus William Alexander shows actual precipitation trends are actually linked to sunspot cycles which IPCC models ignore. See:
Linkages between solar activity, climate predictability and water resource development
JOURNAL OF THE SOUTH AFRICAN INSTITUTION OF CIVIL ENGINEERING
Vol 49 No 2, June 2007, Pages 32–44, Paper 659
5) Ocean Cycles ENSO, PDO
Ocean cycles cause major changes in atmospheric temperature. By excluding these in climate modeling, they have been missinterpreted warming as due primarily to CO2.
E.g. see articles on PDO at ICECAP.US
And on PDO and Clouds Roy Spencer
etc.
Look forward to your incorporating these effects into your tutorial.

HasItBeen4YearsYet?
February 26, 2009 7:23 am

warming on other planets, a short overview…
http://motls.blogspot.com/2006/05/global-warming-on-jupiter.html

February 26, 2009 7:29 am

It seems that we could melt metals down (except, of course, mercury and gallium) using “the green house effect”!!. You forget that the volumetric heat capacity of air is 3,227 times less than that of water, in case of air convection takes all heat to stratosphere and there dissipates and in the case of water you have a limit: it evaporates( Remember?: The “water cycle”). Atmosphere has its limits also, then you can not suppose it having an infinite height.Have you experienced a total solar eclipse? Temperature drops inmediately.

gary gulrud
February 26, 2009 7:34 am

“this is the first articel und WUWT that is disappointing for me. It is not a correct description of the situation.’
I’m afraid I must agree. This is an “Atmospheric Science” paradigmatic presentation.

mangodscott
February 26, 2009 7:45 am

I’m likely late to the party, but has everyone signed the Global Warming Petition at http://www.oism.org/pproject/ and read the paper there ( http://www.oism.org/pproject/GWReview_OISM300.pdf ) ?
Or even better, has everyone read the paper “Falsi cation Of The Atmospheric CO2 Greenhouse Eff ects Within The Frame Of Physics” by Gerhard Gerlich and Ralf D. Tscheuschner at http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v2.pdf ?
These papers seem to thoroughly debunk anthropogenic global warming by CO2 emissions, unless I’m missing something. I would like to read comments on that second paper, if anyone will comment.

Dave L
February 26, 2009 7:53 am

I own a large greenhouse, 28ft wide by 96 ft long by 12 ft high in the center. Please come visit me sometime, and we will go and sit in my greenhouse while you explain your correlation with the Earth’s greenhouse theory.

John Galt
February 26, 2009 7:57 am

gary gulrud (07:34:42) :
“this is the first articel und WUWT that is disappointing for me. It is not a correct description of the situation.’
I’m afraid I must agree. This is an “Atmospheric Science” paradigmatic presentation.

Can you explain what’s wrong with it?
One commenter noted it didn’t include cosmic rays, convection, precipitation, ocean cycles, etc. This post isn’t about the entire climate system, it’s about the greenhouse effect. Hence, the title “A short primer: The Greenhouse Effect Explained”. It doesn’t claim to be anything else.
Now where does the post go wrong? What is factually incorrect, and why? What’s the correct explanation of the ‘greenhouse’ effect?

Alan Siddons
February 26, 2009 8:02 am

Steve Goddard’s tutorial consists of the same old assertions. But you can’t prove a theory by simply repeating its tenets.
Let’s be clear: Electromagnetic energy has no temperature, yet it heats material bodies. So the greenhouse effect is not regarded to trap heat but IS regarded to trap and amplify radiant energy, bringing about the same result. This “trapped radiation” notion harks back to a misconception about glass enclosures, thus the name this theory goes by. It was thought that greenhouses got hot by preventing the exit of “dark radiation.” So radiant energy increased inside the enclosure until it could overpower the glass barrier such that outgoing energy was equal to incoming. Steve’s version is nothing more than a restatement of this fictitious mechanism.
In short, a false belief about greenhouses was the basis of the atmospheric theory — yet the atmospheric theory was RETAINED even after the physics was disproved. Meaning that the atmospheric theory doesn’t have an empirical leg to stand on, no analog in the real world.
The temperature inside a glass house has nothing to do with suppressing the exit of infrared. If solid, IR-reflective glass panes do nothing to amplify thermal radiation within a tight enclosure, however, how much less than nothing do a few swirling gas molecules accomplish in an open atmospheric canopy?

February 26, 2009 8:06 am

Ric your hyperlink is not working.
Am I getting the message from this thread, that among thoughtful scientific skeptics there is no clearly agreed science of the CO2 GHG efect – somewhat at odds with what Steve Goddard asserts?
What baffles me is, surely the CO2 GHG effect should be testable under lab conditions. A column of pure CO2 equivalent to the CO2 content in the air column naturally – what height would that be? then double it, halve it, wet it, microwave it with different wavelengths, etc. Has this been done? if not why not? Or is this a very naive question?

Dave
February 26, 2009 8:06 am

What about the feedback affect on vegetation?
I understand that if you put more CO2 into the atmosphere, plants grow better. And one of the things that plants can do overtime is to take CO2 out of the atmosphere.
It is one of the ways in which everything is kept in balance.

February 26, 2009 8:08 am

jae,
What is going on with the humid areas versus arid areas is the rate of absorption and emission of radiation. It is actually the main point of contention between everyone. In a humid area you have a much larger water content in the atmosphere. This requires more time to warm to its maximum temperature since waters absorption rate for heat is 23 times that of air. If you were to look at when a peek temperature occurs in an arid area versus a humid one you would see a time differential as the radiation takes longer to absorb in a humid area versus an arid one ( this would be considering that the atmosphere around the area was static which it isn’t but that is a different issue ) It also explains the rapid decrease in temperature once the sun is no longer as direct for arid zones where as with humid areas it takes longer to then radiate the heat away.
To be honest I think the main problem with the AGW hypothesis is that it says temperatures are going to increase. Technically what should be happening is the long run is that the temperatures should become MORE STABLE instead of the wild swings that we currently have. Much like the temperature in a humid tropic zone does not get too warm during the day or too cold during the night the same should become more true as more Carbon Dioxide, Water Vapor, and Methane are dumped into the Atmosphere.
Of course that probably would not get the same attention as were all going to die unless we so something now. Can you imagine a headline like this, “Earth’s Atmosphere to become more stable through release of greenhouse gases, Film at eleven!”
Plus what incentive is it to change your spending habits, lifestyle, etc. If all that is really going to happen is it will take longer to get warmer in the daytime and longer to cool off at night? If you actually look at most temperature records the increase of temperature is not surprisingly, at night. Which makes sense as it takes a little while longer to radiate that heat back out into space.
Now what a die hard AGW will tell you is everything I have told you is right BUT what is going to happen is that in the morning the temperature from the morning is still going to be warmer then it was the day before and thus cause run away Global warming because the next day it will warm up more and more and more. But we already have a perfect example in Humidity as to the actual effects of this process so I would suggest that this is pure conjecture without any real evidence. Could it happen or be happening… Doubtful, but I am always open to convincing evidence, which I have yet to see myself. Density of the atmosphere and how much radiation hits the planet would have a much more significant impact on the planets temperature then the STABILIZATION power of CO2 or Water Vapor.

HasItBeen4YearsYet?
February 26, 2009 8:09 am

@Adolfo Giurfa (07:29:01) :
“Have you experienced a total solar eclipse? Temperature drops inmediately.”
….unless it’s really humid.
And, it gets cold at night. In New England, at the end of Autumn, there were some days when it was in the 90’s, but at night it would go down into the mid 30’s, then back into the 90’s next day. It was also very dry that week.

jae
February 26, 2009 8:10 am

6:58:33, Steve:
OK, pick some other low-elevation desert. How about Daggett, CA, which has one of the lowest average July humidities of anywhere in the USA at . 24 % RH. The average minimum July temp. is still above Atlanta at 23.3 C. There is certainly no UHI in Daggett!!!

Ed Scott
February 26, 2009 8:12 am

Is this the Steve Goddard who is department chair, computer science and engineering at the University of Nebraska-Lincoln? If so, this is unbelievable.

Steven Goddard
February 26, 2009 8:14 am

Deanster and Mary Hinge,
Your points are partially correct. Successive reemissions tend to change the wavelength of the IR, and move into H20 absorption bands. If you assume (perhaps incorrectly) that H20 is fixed, then the effect of increased CO2 diminishes. However, some climate scientists argue that increased CO2 leads to increased atmospheric H2O, thus the need for accurate climate models.
This is not a problem which can be solved qualitatively.

February 26, 2009 8:15 am

Johnny Honda (03:27:08) :
Why is the day temperature on the moon ca. 160 °C ? No Greenhouse gases!
No gas at all, so temperature as we measure it here on Earth [Stevenson screens, etc] is meaningless. The SURFACE temperature [of the lunar soil] is 160°C.
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. 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.

R Stevenson
February 26, 2009 8:15 am

If LW radiation is saturated by a short column (3600m) of air containing 350ppm of CO2. A higher density of CO2 say 700ppm will not absorb any more LW radiation and the atmosphere will not get hotter. Energy will be absorbed in a shorter distance (2000m) and heat energy will be mixed by convection. What you say above is not true.

jae
February 26, 2009 8:16 am

John Galt: see above comment, re: UHI. Look at ANY low elevation desert. Here’s a link: http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/sum2/state.html
“Your comparisons to other cities with the same latitude as Phoenix are also incorrect. Atlanta is not in a desert and does not have the same day-time highs as Phoenix.”
?? What are you trying to say, here?? No, Atlanta is not a desert, and it has three times as much greenhouse gases as Phoenix, yet it’s temperatures (day, night, average) in the summer are lower. Why doesn’t the “greenhouse effect” make Atlanta warmer, especially at night?

February 26, 2009 8:16 am

As a layperson running a web site on global warming issues, I’m always seeking articles and postings that help novices with the understanding of the complex science involved with the climate. When I saw the headline of this post, I was very hopeful that I would be able to link to it. Unfortunately, after reading it twice, I’ve come to the conclusion it represents a mangled explanation of the greenhouse effect and just continues (increases) the confusion many have on this critical issue. Although your science may be correct, it is poorly explained.
With my last statement, I would recommend a re-write of the post to make it an understandable explanation, with these suggestions:
1. Remove the “feedback” issue from this post and do a Primer #2 on that topic.
2. If you are going to speak about Mars and Venus, put their unique situations in context versus Earth. The way you use them as examples, suggests there is an apple to apple to apple comparison regarding CO2.
3. Drop the “There is no dispute about this in the scientific community” attitude. When I see this, and like-phrases, an immediate B.S. alarm goes off. I especially like your use of this phrase right before you point the reader to a graph that has 3 representations from 3 different studies – the graph tells me there is a scientific dispute. Learn to state to your readers whether something is scientific theory or scientific fact (actual empirical evidence). If it is scientific theory, then it is in a state of “dispute.”
4. In reference to point #3, when you do a re-write, list those points/issues that are scientifically proven. When you are speaking to points that have not been scientifically proven, label them as such. I have great interest in reading your opinions and speculations but don’t mislead by implying certain issues are scientific fact beyond dispute.
5. Don’t ever use the phrase “As Dr. Hansen has correctly argued” or ever refer to him as a means to convince a reader, as it totally undermines any credibility that you are hoping to establish with the reader. It is well understood that he is a political advocate who will manipulate the data and “models” to embellish his arguments. Honestly, how hard would it be to find a reputable scientist and source to make your point?
C3H Editor, http://www.c3headlines.com

HasItBeen4YearsYet?
February 26, 2009 8:20 am

@David L. Hagen (07:22:05) :
Nice! Although, in part I think you are only confirming what he said at the end, “If you want to make a knowledgeable argument, learn about the feedbacks. That is where the disagreement lies.” (Even for the Svensmark and Shaviv stuff which aren’t direct actions since their mechanism seems to be more in modulating the “feedbacks.”)

jae
February 26, 2009 8:24 am

It is getting harder and harder to attribute a significant temperature change to CO2, since there has been no significant increase in temperature for 10-11 years, now. It looks like something else is totally overwhelming any CO2 effects. Oh, maybe it’s the SUN 🙂 See Shaviv’s latest ideas over at Lubos’ site.

Simon Evans
February 26, 2009 8:34 am

MattN (05:53:05) :
BTW, excellent post Steve. The strawman argument that all alarmist use is that we (skeptics/deniers/flat-earthers) do not believe adding CO2 increases temperature when the ENTIRE argument is in the feedbacks.
Have you read through this thread, Matt? It might be a strawman argument if aimed at you, but clearly not so in the case of many others (unless I have imagined all the resistance expressed here to the basics of SG’s article). This is what becomes so bewildering in any of the debates on this site, the fact that anyone expressing scepticism about the prevailing view here is then assailed by a multitude of mutually contradictory arguments. I wish the argument was as you suggest (or mainly at least), but it isn’t so here.

Alan Chappell
February 26, 2009 8:34 am

CNN is showing some spectacular shots of the volcano eruption in Chile, looks like a real big bang, now I wonder who is going to tax that?

Mark O
February 26, 2009 8:38 am

Anybody who uses the Earth, Mars, Venus analogy when discussing AGW without mentioning the difference in solar radiation these three bodies receives is either ignorant or trying to fool people.
Yet Mr. Goddard thought this argument was so persuasive that it is the fourth sentence in his article.

tmtisfree
February 26, 2009 8:44 am

Johnny Honda (05:04:23) :
And what happened to the LW backradiation to the surface?
It simply warms slightly the surface

Nooo! We must obey the rules of thermodynamics, like Homer. So also the second rule, i.e. no colder matter (atmosphere) can warm a warmer matter (earth).
Correct: The LW backradiation is lessening the net radiation of the surface
You are right, thanks for the correction.
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.
Bye,
TMTisFree

February 26, 2009 8:45 am

This is plain political warming. Did WUWT changed sides?

David Corcoran
February 26, 2009 8:49 am

coaldust (01:12:56) :

This is incorrect. The argument is about feedbacks, but not runaway feedback. There will clearly be no runaway feedback since CO2 has been much higher in the past, and runaway feedback that would “turn our planet into a mirror of Venus” did not occur.

You are correct that the geological record contradicts such an outcome, but believe me, it is still taught as a probable outcome on Earth. Here’s a school lecture:
Science Lecture
“The sobering warning for us is obvious: we have to be extremely concerned about processes such as burning of fossil fuels in large volumes that might (we don’t know for sure because the scientific questions are complex) have the potential to trigger a runaway greenhouse effect and produce on the Earth atmospheric conditions such as those found on Venus.”
And many scientists do continue to warn of a likely runaway greenhouse effect on Earth.
Survey Says…
Life doomed by climate woes: Top British scientist
Scientists who back CAGW rarely if ever contradict their brethren who spead fanciful, apocalyptic scenarios, and benefit from scaring the public.

Ed Fix
February 26, 2009 8:51 am

As evidenced by the graph from junkscience.org “Estimating Clear Sky Grenhouse Effect from Quadrupling CO2” there is a wide range of estimates of how large the actual greenhouse effect is. I have read Miskolczi’s paper “Greenhouse effect in semi-transparent planetary atmospheres”. Like kevindick, my most recent course in differential equations is over 20 years in the past, but I couldn’t spot any glaring errors.
The criticisms I’ve seen assert (without support, analysis, or explanation) that Miskolczi mis-applied the virial theorem or Kirchoff’s law, but what they completely fail to attempt to explain is why Eddington’s 1916 solution is better for this application than Miskolczi’s.
Any thoughts?

Steven Goddard
February 26, 2009 8:52 am

I have no affiliation with the University of Nebraska, and in fact have never been to Nebraska.

Brendy
February 26, 2009 8:53 am

Patronizing lectures from “omniscient” experts illustrate little more than their own hubris.

Steven Goddard
February 26, 2009 8:56 am

All, there are a million points which this article does not cover. It is just a first order explanation of the greenhouse effect.
Have at it!

Steven Goddard
February 26, 2009 8:58 am

Hank,
There isn’t a lot of LW arriving from the sun. Temperatures on the sun are too hot.

Barry Foster
February 26, 2009 8:59 am

Interview with James Lovelock (he os the bizarre Gaia theory) currently on BBC Radio4: He says there are a thousand climate scientists on the IPCC, and that the seas are rising at twice the level the IPCC predicted. He also says that sea level rise is a barometer on global warming and that if you google sea level rise you’ll see it’s rising.
Hmmm. Is any of that correct, or has this tired man gone off the silly end of the pier completely?
Interview will be available on BBC’s ‘Listen Again’ very soon under ‘Material World’. Listen and weep. Anyone got his address, as I’d like to send him a letter?

Joel Shore
February 26, 2009 9:01 am

Steve Goddard,
Thanks very much for this post. You and I may not agree on that much but I am very pleased to see you clearly spell out those things that there is at least some reasonable scientific uncertainty about (feedbacks) vs those things that are really silly to debate (e.g., whether CO2 is a greenhouse gas that causes a forcing of ~4W/m^2 when its concentration doubles). There are lots of commenters on this website who seem to spend their time talking about things where the science really is so settled that they don’t do themselves any favors by continuing to bring it up.
David Corcoran says:

For instance: Dr. Hansen says the seas will rise 25M in 91 years, I don’t know why low lying nations are stubbornly insisting on making him a liar.

Do you have a cite for Hansen making such a claim?
Bill Yarber says:

Your use of Mars, Earth and Venus to prove that CO2 putis a major green house gas is totally flawed. You completely neglect their diameters and their distance from the Sun.

Diameter doesn’t matter. Distance from the sun obviously does. However, compare Venus to Mercury. Mercury, with very little atmosphere has a huge range in temperatures between the side facing the sun and the side facing away but even the side facing the sun is not as hot as Venus, despite being closer.

Steven Goddard
February 26, 2009 9:01 am

If the atmosphere heats up, then the oceans will too. This is because the difference in temperature has to remain fixed to maintain equilibrium of heat flow.
I have no agenda for this article, other than the WUWT standard – to find out the truth, and get people talking and thinking. This is the #1 science blog after all.

Mike T
February 26, 2009 9:02 am

Question – what is the concentration of CO2 at the various levels in the air collumn? Seems to me that CO2 is heavier the O2 and normal air, it will be concentrated near the ground, not high up. But, according to your graph, CO2 doesn’t even begin to have an effect till you get to around 100 millibars. That translates to over 50,000 feet & I seriously doubt we have anything like even a measurement of CO2 concentration at that altitude and, if we do, I’ll bet it’s very, very low and can be shown to have little to no effect on warming the surface.

MattN
February 26, 2009 9:03 am

Simon sez:
“Have you read through this thread, Matt? It might be a strawman argument if aimed at you, but clearly not so in the case of many others (unless I have imagined all the resistance expressed here to the basics of SG’s article). ”
Yes I have. 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.

Hank
February 26, 2009 9:03 am

Chuckle, chuckle. Skepticism on the rampage.
A thing I always wondered about. Since an element of the greenhouse gas explanation involves the sun’s radiation penetrating the atmosphere. How does this play out in the oceans where sunlight penetrates into the ocean and must likewise re-radiate there? Isn’t there anything comparable to greenhouse gases in the ocean? Dissolved CO2 perhaps?
Isn’t it also important to explain that the greenhouse metaphor has a defect since most of the heating in a greenhouse is due to the fact that the heat can’t convect away?

February 26, 2009 9:09 am

Steve Goddard wrote:
“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.”
This is a juvenile way to look at the phenomenon!
The energy source here in this planet is the ocean and no one can think that air warms the ocean.
All the energy that the ocean gets every day from the Sun has to be re-radiated back to the outer space, after some processes, i.e. convection, meteorology in general and greenhouse effect, all processes that pertain to the atmosphere.
The more the atmosphere is prone to let energy pass through it, the more the ocean loses energy.
So, please, stop saying that the ocean is warmed by air.
The only correct way to express the concept is that a change in those processes pertaining to the atmosphere can change the rate of energy that is lost towards the outer space.
Moreover, since meteorology has a fundamental part in the redistribution of energy from the source to other parts of the planet (and then lost) as well as it influences the planetary albedo, only climate modelists can think that the problem is a linear one!

February 26, 2009 9:10 am

We are living in “interesting times” really. In the next NH summertime GWrs´will attack again, they will feel reinforced in their beliefs as La Nina produces droughts in the US midwest and west.

gary gulrud
February 26, 2009 9:11 am

Courtesy of George Smith from a recent thread:
“GHG molecules act as individual molecules; they don’t even know there is another like them in the whole universe. At 385 ppm, a CO2 molecule is one of 2597 molecules, and its nearest neighbor CO2 is 14 molecules distant in any direction. The next thing that happens to ANY GHG molecule, either water or CO2, is that it immediately collides with the normal atmospheric gases of Nirogen, Oqygen and Argon, and that energy from the absorbed photon becomes energy of thermal agitation of the ordinary air molecules. Only at extreme altitudes would any GHG molecule have a long enough mean free path to re-emit the photon it absorbed out of the thermal IR or solar spectrum; at lower altitudes the energy becomes thermalized in the normal atmospheric gases.”
The emissivity of CO2 at STP is 9*10^-4 or 1/1000 that of green leaves. The emissivity is directly proportional to the time required for the interaction, the emission of a photon, to occur.
Back-radiation has no practical consequence of heating the surface whatever.

Joel Shore
February 26, 2009 9:11 am

Molon Labe says:

Utterly ridiculuous and contradictory. If CO2 absorption is “saturated”, adding more CO2 cannot have any effect. Period.

Wrong for two reasons: first there are always the wings of the band where things are not saturated. Second, there is always a height in the atmosphere where the atmosphere is low enough density that this saturation no longer occurs. At the end of the day, what matters is not just if the IR is absorbed but WHERE it is absorbed…Or, more precisely, the last altitude it is absorbed before it escapes the earth because the temperature at this altitude is what will determine the rate of radiative emission int space. (Power radiated ~ T^4).
Jim G says:

Is this why there should be a CO2 hotspot in the troposphere above 100,000 ft?

If you are talking about the “hotspot” expected in the tropical troposphere then no. It is not a “CO2 hotspot” because it is expected to occur independent of the mechanism causing the warming. (See here for a comparison of the structures of GHG-caused and solar-caused warming: http://www.realclimate.org/index.php/archives/2007/12/tropical-troposphere-trends/ ) It turns out that the structure of the warming in the tropical troposphere is not determined by where the energy is absorbed but rather by moist adiabatic lapse rate theory. I.e., the atmosphere has lots of convection in it, so the temperature structure is determined in large part by this convection.

John Galt
February 26, 2009 9:13 am

jae:
I’m sorry, but I’m not really sure what you’re trying to say.
I’m saying both Phoenix and Atlanta have man-made micro-climates and both warm more during the day and cool less at night because of it.
I am also saying I don’t believe your comparison of Atlanta and Phoenix is a good example of what you’re trying to illustrate. The natural climate of those cities is very different and being at the same latitude does not make them comparable.
As to whether high-altitude deserts and low-altitude deserts cool differently at night, I made no comment. If that is really you’re point, Atlanta is not a good example to use as it not in any kind of desert.
If I misinterpreted what you’re saying, I apologize.

Steven Goddard
February 26, 2009 9:15 am

Leif,
Your explanation is suspect. If LW emission from a molecule of CO2 had only two possible destinations (space or ground) then the fact that CO2 absorption saturates in the lower two meters would imply that increased CO2 has no effect.

John Galt
February 26, 2009 9:19 am

Lucy Skywalker (08:06:25) :
Ric your hyperlink is not working.
Am I getting the message from this thread, that among thoughtful scientific skeptics there is no clearly agreed science of the CO2 GHG efect – somewhat at odds with what Steve Goddard asserts?
What baffles me is, surely the CO2 GHG effect should be testable under lab conditions. A column of pure CO2 equivalent to the CO2 content in the air column naturally – what height would that be? then double it, halve it, wet it, microwave it with different wavelengths, etc. Has this been done? if not why not? Or is this a very naive question?

All good questions, Lucy. If science can’t agree on how the greenhouse effect works, then we really don’t know much about the climate, do we?
Follow-up questions: How does increases in atmospheric CO2 affect the climate? Do lab results reflect the real world?

Steven Goddard
February 26, 2009 9:20 am

Gary Gulrud,
You wrote: Back-radiation has no practical consequence of heating the surface whatever.
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.

gary gulrud
February 26, 2009 9:21 am

“If the atmosphere heats up, then the oceans will too. This is because the difference in temperature has to remain fixed to maintain equilibrium of heat flow.”
This is manifestly not equivalent to “increases in atmospheric temperature cause the ocean to warm up.”
Now you have need of two clarifications.

Phil.
February 26, 2009 9:22 am

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.

R Stevenson
February 26, 2009 9:26 am

SW radiation cannot penetrate the atmosphere of Venus. The heat from the planet’s centre is conducted through the thin crust and passes by convection and radiation into the atmosphere; there is no greenhouse efect on Venus. A short column (3600m) of air (350ppm CO2) filters out the relevant wavebands from LW radiation. Increasing the CO2 concentration would not absorb more radiation, it would only shorten the absorption distance. The heat energy would mix by convection and the temperature of the atmosphere would not rise. What you have said above is incorrect.

John Galt
February 26, 2009 9:27 am

Steven Goddard (08:52:13) :
I have no affiliation with the University of Nebraska, and in fact have never been to Nebraska.

Nebraska is just like Kansas, but without all the glitz.

Roger Knights
February 26, 2009 9:30 am

OT: Bloomberg News story:
“Greenland, Antarctica Glaciers Speeding Faster Toward the Sea”
http://www.bloomberg.com/apps/news?pid=20601124&sid=aTg9EF2NtBCg&refer=home
Sample:
“Altogether, the glaciers in the West Antarctic are losing about 103 billion tons a year of ice in discharge,” he said. “This discharge from west Antarctica would add an additional 10 to 20 centimeters” to the existing UN predictions of sea level rise this century, he said.”

David Y
February 26, 2009 9:33 am

Anthony (and Steve)–Great post, and excellent discussion/contributions. While I’m not a scientist, for ‘climate hobbyist’ like me this is a really enjoyable ’roundtable’ exchange and a great example of what an outstanding forum WUWT is–and why I ping your site several times each day. Thank you!

Jim the Layman
February 26, 2009 9:33 am

Anyone happen to know what is the estimated amount of CO2 in the atmosphere and the amount that human activity puts into the atmosphere? It might be helpful to be able to put some perspective on this as it would seem that human activity would be so miniscule as to be dismissable, no?

jae
February 26, 2009 9:34 am

“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?

DR
February 26, 2009 9:35 am

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.

February 26, 2009 9:41 am

“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.

Simon Evans
February 26, 2009 9:41 am

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).

Steven Goddard
February 26, 2009 9:44 am

John,
I’m sure Nebraska is a lovely place, but I’m still trying to figure out where Springfield is.

tmtisfree
February 26, 2009 9:44 am

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

HasItBeen4YearsYet?
February 26, 2009 9:49 am

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.)

alex verlinden
February 26, 2009 9:50 am

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 …

Robert Wood
February 26, 2009 9:54 am

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.

Gerald Machnee
February 26, 2009 9:56 am

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.

Phil.
February 26, 2009 9:56 am

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).

Steven Goddard
February 26, 2009 9:57 am

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.

David Porter
February 26, 2009 9:58 am

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.

gary gulrud
February 26, 2009 9:59 am

“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.

schnurrp
February 26, 2009 10:00 am

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.

Phil.
February 26, 2009 10:01 am

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’?

george h.
February 26, 2009 10:03 am

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”

Steven Goddard
February 26, 2009 10:04 am

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

Simon Evans
February 26, 2009 10:06 am

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.

Steven Goddard
February 26, 2009 10:07 am

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.

Timo Hämeranta
February 26, 2009 10:08 am

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.

Editor
February 26, 2009 10:10 am

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.

Am I getting the message from this thread, that among thoughtful scientific skeptics there is no clearly agreed science of the CO2 GHG effect – somewhat at odds with what Steve Goddard asserts?
What baffles me is, surely the CO2 GHG effect should be testable under lab conditions. A column of pure CO2 equivalent to the CO2 content in the air column naturally – what height would that be? then double it, halve it, wet it, microwave it with different wavelengths, etc. Has this been done? if not why not? Or is this a very naive question?

There are pressure and temperature effects that complicate things, and you want the nitrogen and oxygen around, as I believe there are energy transfer issues between CO2 and surrounding gases.
Some of that work has been done, but I think quite a long time ago and hence not done to look at everything we’d look at now.

SandyInDerby
February 26, 2009 10:13 am

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?

February 26, 2009 10:14 am

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

foinavon
February 26, 2009 10:14 am

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

Phil.
February 26, 2009 10:17 am

David Porter (09:58:46) :
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.

It’s the radiational cooling of the atmosphere by altitude and wavenumber (& hence species).
S A Clough & M J Iacono, J Geophysical Research, vol 100, pp16519, 1995.
Note it’s not ‘GHG absorption by altitude and wavenumber’.

jae
February 26, 2009 10:18 am

“Isn’t the effect of co2 logarithmic?”
It is debatable as to whether the effect is exactly logarithmic, but it is close enough, at least for the present concentration levels. It is important to realize that the water greenhouse effect is also logarithmic (at least according to MODTRAN). This probably helps to explain my connundrum about why it’s not hotter in Atlanta than in Daggett during July–there is still a sufficient amount of water vapor in Daggett to cause most of the “greenhouse effect,” so that the extra water vapor in Atlanta doesn’t add that much. By the same token, any additional water vapor that results from a 1.2 C heating from 2 X CO2 (about 8%, by my calcs) cannot possibly cause a significant “positive water vapor feedback.”

jae
February 26, 2009 10:22 am

“The coldest winter I ever spent was my summer in San Francisco”
Mark Twain”
Yes. Your hands don’t feel so warm when you ride your bicycle in the winter, right? This is because the water vapor makes your hands much colder in winter. This is due to the fact that it has a thermal capacity about 4 times that of the rest of the air. Same reason it makes your hands feel warmer when the air is warmer. I doubt that it has anything to do with “backradiation.”

Steven Goddard
February 26, 2009 10:33 am

Gerald,
Sorry I meant to say that fog blocks SW (not LW) which is the dominant factor during the day. LW blocking is more interesting at night.
Timo,
Thanks for the timely article!
David Porter,
Spectral cooling is a tricky concept, but basically correlates with IR absorption. A reasonable explanation here:
http://books.google.com/books?id=6xUpdPOPLckC&pg=PA409&lpg=PA409&dq=spectral+cooling+rate&source=bl&ots=NnNKiOSiRA&sig=Fny7_S8C9BIAXbp6iWbOtPFesfc&hl=en&ei=SN6mSbW4OoK2sQOizvngDw&sa=X&oi=book_result&resnum=9&ct=result#PPA409,M1

Phil.
February 26, 2009 10:34 am

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.”
Perhaps you can enlighten us all as to “how” this is “fundamentally flawed”

Since we’re talking about the earth’s outgoing IR radiation only the 15µm band is relevant, this covers approximately 25% of the radiated spectrum (not 8%). The absorption spectrum isn’t saturated (only at the line centers) so an increase in [CO2] causes an ~logarithmic response in the lower troposphere. It also ignores the fact that IR emitted from clouds passes through a higher, thinner part of the atmosphere.

tmtisfree
February 26, 2009 10:37 am

A new paper by Nir J. Shaviv entitled:
Using the oceans as a calorimeter to quantify the solar radiative forcing
Abstract:
Over the 11-year solar cycle, small changes in the total solar irradiance (TSI) give rise to small variations in the global energy budget. It was suggested, however, that different mechanisms could amplify solar activity variations to give large climatic effects, a possibility which is still a subject of debate. With this in mind, we use the oceans as a calorimeter to measure the radiative forcing variations associated with the solar cycle. This is achieved through the study of three independent records, the net heat flux into the oceans over 5 decades, the sea-level change rate based on tide gauge records over the 20th century, and the sea-surface temperature variations. Each of the records can be used to consistently derive the same oceanic heat flux. We find that the total radiative forcing associated with solar cycles variations is about 5 to 7 times larger than just those associated with the TSI variations, thus implying the necessary existence of an amplification mechanism, although without pointing to which one.
In:
Shaviv, N. J. (2008), Using the oceans as a calorimeter to quantify the solar radiative forcing, J. Geophys. Res., 113, A11101, doi:10.1029/2007JA012989.
Bye,
TMTisFree

Ray
February 26, 2009 10:39 am

If you want the full, and I mean FULL picture of the Climate Change science, check this compilation by Ken Gregory of Alberta… http://members.shaw.ca/sch25/FOS/Climate_Change_Science.html
It is very complete and full of details.

Steven Goddard
February 26, 2009 10:42 am

Simon Evans,
During the last ice age, Chicago was thousands of feet deep in ice. Summers then were undoubtedly more than 4C cooler than they are now.

Bob Shapiro
February 26, 2009 10:53 am

DocWat: That’s a good layman’s description of what’s going on. The problem in calculation comes from not knowing the specifics well enough. Knowing the specifics is 99%, and making the calculations is 1%
Steve: R.W. Wood debunked the idea that a greenhouse works by trapping radiation 100 years ago. If his experiments were wrong, please explain where his mistake was.
If he’s right, then the various posters have it right when they say: 1. More solar energy hitting the earth (higher solar flux or proximity to the sun) makes the earth warmer (and vice versa), 2. The albedo or land, sea, & ice determine how much of that energy is “usable” to warm the earth, and 3. A “thicker” atmosphere means convection energy loss takes longer, allowing the temperature to be higher.

Joel Shore
February 26, 2009 10:57 am

warm puddle says:

also http://xxx.lanl.gov/abs/0707.1161 claims to falsify the GE.
I think the practical testing issue needs to be resolved as does the contradiction of the second law of thermo dynamics beforfe I take the GE as rock solid theory.

Gerlich and Tscheuschner are wrong. This paper debunks some of what they claimed: http://lanl.arxiv.org/abs/0802.4324
I’m a physicist and their claim that the atmospheric greenhouse effect violates the 2nd law of thermodynamics is easily shown to be wrong. What the 2nd law says is that the net flow of heat would have to be from the (warmer) earth to the (cooler) upper atmosphere. G&T seem to believe that the idea that the earth is warmer with an IR-absorbing atmosphere than in its absence then implies that the net heat flow is in the other direction. However, that is not the case. The net flow is still from the earth to the atmosphere. The warming occurs because the case one is comparing to is the case when there is no IR-absorbing atmosphere and hence NONE of the radiation that the earth emits is returned to it. Thus, the fact that the atmosphere returns any of the radiative energy emitted back to the earth, even if it returns only a fraction of what it receives from the earth, is enough to cause the temperature to be higher than it would be in the absence of an IR-absorbing atmosphere.
Or, as is succintly stated here http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html , “The surface of the Earth is warmer than it would be in the absence of an atmosphere because it receives energy from two sources: the Sun and the atmosphere.”

Joel Shore
February 26, 2009 11:04 am

Steve Goddard says:

Simon Evans,
During the last ice age, Chicago was thousands of feet deep in ice. Summers then were undoubtedly more than 4C cooler than they are now.

Global mean means just that, GLOBAL MEAN. Some places cooled by more than 4C – 7C and some places cooled less. The polar regions cooled the most and the tropics the least. There was also presumably more cooling over continents than over the oceans. There also may have been some seasonal differences although I am less sure about that.

February 26, 2009 11:06 am

I tackled this general subject a while ago and it can be found here:
http://co2sceptics.com/news.php?id=1562

HasItBeen4YearsYet?
February 26, 2009 11:07 am

http://www.wilderness-survival.net/desert-2.php

“The temperature of desert sand and rock averages 16 to 22 degrees C (30 to 40 degrees F) more than that of the air. For instance, when the air temperature is 43 degrees C (110 degrees F), the sand temperature may be 60 degrees C (140 degrees F).
Wide Temperature Range
Temperatures in arid areas may get as high as 55 degrees C during the day and as low as 10 degrees C during the night. The drop in temperature at night occurs rapidly and will chill a person who lacks warm clothing and is unable to move about. The cool evenings and nights are the best times to work or travel. If your plan is to rest at night, you will find a wool sweater, long underwear, and a wool stocking cap extremely helpful. “

Stevo
February 26, 2009 11:09 am

I’ll add yet another conflicting explanation.
The IPCC cites Held & Soden 2000 to describe the mechanism as due to the pressure difference between the average altitude at which IR radiates into space, and the surface. When air is compressed it gets hotter, which means that as it moves vertically it changes temperature, leading to the adiabatic lapse rate. As air near the surface is warmed, convection speeds up until the lapse rate is restored. The effective temperature at which the Earth radiates, and hence the temperature of the ‘top’ of the atmosphere, is fixed by the temperature at which the heat out as calculated by the Stefan Boltzmann equation is equal to the total heat in. The greenhouse effect is the difference between this top-of-atmosphere radiative temperature that would apply without atmosphere, and the surface temperature, which is hotter because of the adiabatic lapse rate. The greenhouse effect is nothing to do with “trapping” IR, it’s physical mechanism is pressure.
And the enhanced greenhouse effect is because increasing CO2 means the average height of emission is raised, so you’ve got a bigger pressure difference.
If temperature increased with altitude, then more CO2 would result in cooling. This shows even clearer that it isn’t a “trapping” effect.
And Venus works the same way, except that with 90 times more atmosphere and high altitude clouds, the emitting layer is more like 50 km up instead of only 5 km up, and so the pressure-induced temperature difference is massive. (Because of its higher albedo, Venus actually absorbs less energy from the sun than Earth, despite being closer.)
Oh, and the tropical troposphere ‘hotspot’ is a result of the water vapour feedback mechanism predicted to treble global warming. It’s absence is a blow not to the validity of CO2 greenhouse physics, but to the postulated feedbacks.
I’d like to hope that might help, but I’m afraid it will only add to the confusion.

Joel Shore
February 26, 2009 11:12 am

coaldust says:

This is incorrect. The argument is about feedbacks, but not runaway feedback. There will clearly be no runaway feedback since CO2 has been much higher in the past, and runaway feedback that would “turn our planet into a mirror of Venus” did not occur.

While I tend to agree that you are probably right, your argument is not airtight, as Hansen has pointed out. Firstly, the sun has gradually brightened over time. Secondly, Hansen argues that some negative feedbacks that operate at geologic timescales (mainly involving the GHGs themselves, I believe) could be inoperable here due to the very fast pace with which we are increasing the GHGs.
So, to summarize, the general scientific view has been that a true runaway cannot occur on earth at the moment…I.e., that the positive feedbacks are sufficient to magnify the effects of the GHGs but not enough to lead to an instability that would lead to a runaway effect. However, Hansen claims otherwise at least if we really go to town in burning all available fossil fuels…And, while I remain skeptical of his claim, I don’t think one can immediately dismiss it out-of-hand.

D. King
February 26, 2009 11:12 am

You can’t model a system with this many variables.
This is a moot debate!
Cap and Trade will be implemented.
Energy prices will go up.
“Smart” meters will be installed.
And while you back and forth on this,
…………you know what….forget it!

February 26, 2009 11:12 am

tmtisfree (09:44:54) :
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.
It is not the cooler air that warms the surface, but radiation that goes through the transparent air to reach the surface and be absorbed by the opaque ground.

MartinGAtkins
February 26, 2009 11:15 am

Mark N (23:15:03) :

Thanks, reads like a simple explanation that I could perhaps give it to ten year olds (or is there a better source of information for them?). Was wondering about H2O. I was under the impression that it is the major GHG. Thanks for your patience.

Unfortunately there is no simple explanation. We are dealing with atomic science and the way molecules of gas react when energised. H2O has a higher expansion ratio than CO2 when given the equivalent energy input per volume.
It follows that H2O has an exhilarated contraction when energy is lost or diluted.
At reasonably high temperatures compared with CO2 water molecules form bonds with other H2O molecules and become liquid.
CO2 doesn’t form these bonds until the energy level has fallen a long way below that of H2O.
On top of that pressure plays a part in deciding at what point both molecules start to bond.
If I’m wrong then I hope someone with someone will give a better explanation of why H2O is both a positive and negative feedback in our climate and CO2 is more or less benign.
The off shot is that H2O conserves energy in the lower troposphere but leaks huge amounts of energy in the upper troposphere.

John Galt
February 26, 2009 11:15 am

Colonel Sun (10:14:32) :
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

I cringe everytime I hear ‘CO2 is a greenhouse gas and must be causing warming.’
Our climate system is much more complex than that, yet the entire AGW argument seems to boil down to that statement.

Brian B
February 26, 2009 11:16 am

It is widely agreed that a doubling of CO2 will increase atmospheric temperatures by about 1.2C, before feedbacks.
Is there a citation for this based on strong science, or is it just one of those givens everyone agrees with but no one can precisely say why?
Steve McIntyre has been asking for such a citation for quite awhile now and has apparently given up on ever having one provided.

stumpy
February 26, 2009 11:17 am

Is this explanation of the greenhouse effect based on the hypothesis developed by Arrhenius that was never validated (Arrhenius, 1896). I know of no successful attempts to test this hypothesis practically or theoretically, yet is seems to be wholly accepted as fact. Are there any modern works that prove a greenhouse effect as you explained exists?
The concept that extra co2 would enable more re-radiated energy to be directed back down to the earths surface has always troubled me, yes energy would be directed back on collision, but the net energy flow (warm to cold) would prevent it from going all the way back to the earths surface by collision. The re-emission argument fails when there is a net flow of energy in one direction. It is in breach of the 2nd law of thermodynamics and is essentially a perpetuem mobile of the 2nd kind. Surely radiative forcing forms only part of the GE, with atmospheric mass, stored energy and convection also being key factors.
Suggesting infrared energy that only penetrates the seas surface by 1mm can actually warm the sea is odd, especially when evaporation is considered. Leave a large glass container of water in the shade and one in the sun and see which one warms the most.

lgl
February 26, 2009 11:19 am

tmtisfree
Second law of thermodynamic does not prevent a body to be heated by radiation.
Radiation is not heat, it has no temperature.

schnurrp
February 26, 2009 11:25 am

jae (10:18:07)
What’s missing in the dry desert situation is that central pink column labeled: “sensible and latent heat” on “The annual mean global energy balance for the earth-atmosphere system” diagram. This is the energy necessary to change liquid water into gas (water vapor). This evaporative coooling has a significant effect on the ground temperature and may add to the cloud albedo as well. The lack of liquid water in the desert means that this cooling effect would be minimal.
None of this has much to do with the greenhouse effect though.

Simon Evans
February 26, 2009 11:26 am

Steven Goddard (10:42:24) :
Simon Evans,
During the last ice age, Chicago was thousands of feet deep in ice. Summers then were undoubtedly more than 4C cooler than they are now.

Local variation being much greater than the global mean, most obviously in the case of northern hemisphere glaciation. For the LGM Stenni et al. 2001 found about 9°C in Antarctica, Dahl-Jensen et al. 1998 found about 21°C in Greenland, whilst Sarnthein et al. 2003 and Kucera et al. 2005 confirm
moderate cooling of tropical SST, generally 0°C to 3.5°C, and so on. There are plenty of other studies, of course, but I suggest my 4C to 7C change in the global mean is a fair summary.

Edward
February 26, 2009 11:36 am

Barry
If you google James Lovelock the second thing you’ll find is his website.
Here it is if you want to send him a letter.
http://www.jameslovelock.org/
thanks
Edward

Steven Goddard
February 26, 2009 11:38 am

foinavon ,
This article is intended to be a qualitative overview, not quantitative. The figure just shows that noted skeptic Lindzen believes that increasing CO2 will lead to increasing temperature. As does Spencer, Pielke, etc……

Will
February 26, 2009 11:39 am

Regarding relative humidity and temperature, I’ve noticed RH will often begin to show decline preceding a temperature drop, and then as temps fall RH tracks with it. Having lived much of my time in northern Alaska temperature is an interesting subject…will it be just -20F or should we prepare for -50F. The thing I have come to watch as first sign is whether RH is starting to drop off on a cold night, and keeps dropping as temps fall, to get an idea if it will be cold (superstition?). I’ve wondered if there was such a thing as “apparent” RH when temps are low that confuses the issue. Has anyone else noticed or have an explanation for this seeming not inverse relationship between RH and temp?

aurbo
February 26, 2009 11:42 am

Re:Frank Lansner (04:05:14) :
I’m pleased to see that someone finally mentioned the most significant reason for the differences between the atmospheric temperatures at the surface of Mars and Venus relative to Earth.
Does anybody out there remember what Boyle’s Law describes? In regard to gasses, it was a staple of high-school phsyics when I went to school (over 50 years ago).
It’s PV = nRT
Since n and R are constants, the product of the variables P (pressure) and V (volume) are proportional to T (temperature). That means that if you hold the volume of a gas constant, Temperatures will rise or fall in reponse to like changes in pressure.
The temperature at the surface of Venus is about 465°C as compared to a mean temperature of the Earth of about 15°C. The surface atmospheric pressure on Venus is 92 bars vs a mean pressure of about 1 bar at the Earth’s surface. So one could relate the high surface temperature on Venus to the fact that it’s surface pressure is 92 times that on Earth.
Similarly, the the atmospheric surface pressure on Mars is 0.006 bar or about 6/1000ths the pressure on Earth. The mean surface temperatures ia bout -46°C.
The atmospheres of both Venus and Mars are about 95-97% CO2.
The constituency of the various atmospheres have a lot to do with the Planets’ gravity, a function of its mass. None of these Planets are capable of holding onto hydrogen or helium which have a low escape velocity because of their low mass. Earth’s gravitation is strong enough to hold both oxygen and nitrogen and all three Planets…Mars, Venus and Earth can hold CO2.
Incidentally, a Planet as massive as Jupiter has an atmosphere that’s essentially 100% hydrogen.
If one looks at the upper atmosphere of Venus at a height where the pressure is about the same as at the Earth’s surface….1 bar…guess what? The mean temperature at that level is about the same as on Earth.
Venus lies close enough to the sun so that solar energy is strong enough to vaporize water leaving no significant amounts of compounds in which CO2 can readily dissolve, so once created, it remains in and comprises most of the atmosphere.
As for other non GH gases like Nitrogen (N); although N is only about 3% of Venus’s atmosphere, there is actually 4 times as much N in Venus’ atmosphere as there is on Earth despite the fact that Earths atmosphere is about 79% N. It’s a matter of the density difference.
Despite the attribution by many that Venus’ high surface temperature is a result of the GH effect due to its CO2 rich atmosphere, one might ask why then isn’t Mars (with more CO2 in its atmosphere than here on Earth) warmer than it is? It’s the sun……
In summation, there are lots of other aspects of physics and thermodynamics that have yet to be fully reconciled before a conclusion that GW in general and AGW in particular is responsible for temperature stability, or even more dubious, will be reponisble in the future for Global Warming.
Steve’s primer offers nothing new to the AGW argument.

RH
February 26, 2009 11:43 am

Another exercise that I would suggest people try periodically is to use Weather Underground to compare the daily weather histories for two contrasting locations. As an example look at the record for Tamanrasset Aguenna, Algeria http://english.wunderground.com/history/airport/DAAT/2009/2/26/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA
and Mombasa, Kenya http://english.wunderground.com/history/airport/HKMO/2009/2/26/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA .
Tamanrasset Agenna has a relative humidity of around 10% and Mombasa has a relative humidity of around 94%. Notice the temperature changes between midnight and 7am at both locations. The location with highest humidity should cool the least because of the greenhouse effect. Now we must realize that there are other conditions that can affect the temperature changes between the locations, but if you do this little exercise hundreds of times like I have trying to find locations of similar elevations and alike in all respects but humidity you will begin questioning the importance of the greenhouse effect. We may not see the forest for the trees. Actually if you see this, http://www.telegraph.co.uk/earth/environment/globalwarming/4839985/Scientists-to-stop-global-warming-with-100000-square-mile-sun-shade.html , you might agree that man is rapidly moving back to the trees.

Mike Davis
February 26, 2009 11:45 am

Steven:
Steven Goddard (05:51:38) :
Ric,
I did a canoe trip down the Green River in Utah about 25 years ago in July. It was too hot to sleep when you went to bed, and too cold to sleep when you woke up!
You seem to be confusing evaporation from the river with lower humidity.
Having lived in the desert for 54 years I can say that Jae is correct.
I rode bicycles through the desert at night and new where all the underground streams were by the loss of warmth.

February 26, 2009 11:47 am

Steve Goddard,
Thank you to you and Anthony for posting this, as it does explain many things. However, I believe there is a discrepancy.
You wrote: “The radiative balance has to be maintained in the atmosphere, so the outgoing radiation has a fixed amount of time to escape, regardless of how many GHG molecules it encounters. Otherwise, Homer and your boss will be very angry at you for violating the laws of thermodynamics.”
It appears to me that the global radiative balance cannot be maintained in the atmosphere, as suggested above, if the atmosphere and oceans are to increase in temperature over time due to greenhouse gas effects.
Surely, a hotter atmosphere implies more energy per molecule, and that energy is heat. The same is true for the oceans. Thus, as long as the globe is warming, the input of energy to the earth must exceed the output.
If the GCMs have the energy input equal to the energy output, then that is another bust in the models.
One could argue that the difference is negligible, (input-output) as the earth is very large in mass. I have not run the calculations to confirm.
The first and second laws of thermodynamics require an imbalance between input and output for global warming.
To make this perfectly clear, the normal energy balance equation for a body is:
(mass IN x heat content IN) + (radiation IN) + (heat generation) =
(mass OUT x heat content OUT) + radiation OUT + (heat accumulation)
where:
mass IN and OUT are in pounds per hour, (negligible for the Earth)
heat content is in BTU per pound,
radiation is in BTU per hour,
heat generation is in BTU per hour, and
heat accumulation is in BTU per hour. (British units used)
Also, heat accumulation can be either positive or negative. Heat accumulation is required for the Earth to grow warmer.
Heat generation may be, for the Earth, nuclear power, burning fossil fuels, volcanic and geothermal effects, but not wind power or wave power.

Gibsho
February 26, 2009 11:52 am

Best discussion I’ve seen here.
Relatively free of political science and snarkiness.

Alan Siddons
February 26, 2009 11:52 am

It’s obvious from these posts that belief in this 19th century piece of nonsense is very persistent. Many people are still willing to make excuses for this nutty theory, like astrologers loading more corrective epicycles onto a Ptolemaic model. Given what’s known today about thermodynamics, however, had no one ever heard about a “greenhouse effect” before, no physicist would be foolhardy enough to propose one to explain the earth’s temperature.

Paddy
February 26, 2009 11:52 am

Please excuse my layman’s level of understanding. I am confused by conflicting statements about CO2 levels historically. Steve states that atmospheric CO2 was about 200ppm 14,000 years ago. Dr Will Happer testified before a Congressional committee today (See ICECAP “Scientist tell Congress: Earth in CO2 Famine”). He stated:
“Many people don’t realize that over geological time, we�re really in a CO2 famine now. Almost never has CO2 levels been as low as it has been in the Holocene (geologic epoch) – 280 (parts per million – ppm) – that’s unheard of. Most of the time [CO2 levels] have been at least 1000 (ppm) and it’s been quite a bit higher than that, . . .”
“Earth was just fine in those times,” Happer added. “The oceans were fine, plants grew, animals grew fie. So it’s baffling to me that we’re so frightened of getting nowhere close to where we started,” Happer explained. Happer also noted that “the number of (skeptical scientists) with the courage to speak out is growing” and he warned “children should not be force-fed propaganda, masquerading as science.” In December, Happer requested to be added to the groundbreaking U.S. Senate Minority Report Update: More Than 650 International Scientists Dissent Over Man-Made Global Warming Claims
“Happer was pressed by the Committee on whether rising CO2 fears are valid. “I don’t think the laws of nature or physics and chemistry has changed in 80 million years. 80 million years ago the Earth was a very prosperous palace and there is no reason to suddenly think it will become bad now,” Happer added. Happer is a professor in the Department of Physics at Princeton University and former Director of Energy Research at the Department of Energy from 1990 to 1993, has published over 200 scientific papers, and is a fellow of the American Physical Society, the American Association for the Advancement of Science, and the National Academy of Sciences. Happer was reportedly fired by former Vice President Al Gore in 1993 for failing to adhere to Gore’s scientific views.”
So what was the CO2 concentration 14,000 years ago? If the low end historically is 280ppm, we should be working actively to increase CO2 levels to 1000ppm.
I know that mine safety rules allow for extended exposure to 3000ppm and US Navy allows submarine air to have up to 5000ppm. This should exclude concerns of danger to animal and plant life.
It seems that that no research has been conducted to determine the optimum CO 2 level or the amount below which it becomes dangerous.
Clear up my confusion and ignorance please.

Tom
February 26, 2009 11:58 am

Can somebody tell me what’s wrong with this critical examination of the traffic light analogy:
In the traffic light analogy, the energy is driving from point A (the outside extreme of the atmosphere) to point B (the surface). The author’s point is that the commute takes longer, and since the driver spends more time driving, this equates to an increase in heat.
The problem I have with the analogy is that the energy can only go in one direction. The reality is that when the energy is absorbed (stopped at a light), and emitted (the light turns green), it can be emitted in any direction, including back out towards space. It would be as if to say that there is a 50% chance at every light that the driver will get frustrated waiting for the light to change, and turn around and leave before dropping the kid off for school. Now, at every subsequent light, in each direction, the same choice is made.
It seems to me light as you increase the number of traffic lights (CO2 molecules), the more heating you’d get in the upper atmosphere, and the less would eventually make it to the surface; and here is why – as you approach the surface, the density of the atmosphere (and therefore CO2) increases (more chance to get turned back) – as you travel away from the planet, the density decreases (less chances to get turned back).

February 26, 2009 11:58 am

Phil. (09:56:18) :
near the surface any energy is exchanged via collisions with neighboring molecules almost immediately (timescale less than a nanosecond).
Where do people get these ideas from? Googling the internet? How about some thinking?
Here goes: The heat content of the air is 7/2kT per diatomic molecule (N2 and O2, which is essentially all there is). For each CO2 molecule there are about 3000 N2 and O2 molecules. About 4% of the CO2 molecules will be thermally excited at 300 K. The vibrational frequency of the bend in the molecule is 667 cm-1, kT at 300 K is about 200 cm-1, so the relative population will be exp(-667/200). Therefore, for each excited CO2 molecule there will be 75000 O2 and N2 molecules. The total heat content of those molecules will be 7/2 kT x 75000 ~ 5*10^6 cm-1 [The unit cm-1 as an energy unit is standard for spectroscopy]. The relative amount of deposited energy per excited CO2 is thus about 0.00001of the total energy. The temperature rise per CO2 excited is therefore negligible.

Johnski
February 26, 2009 12:00 pm

Goddard you ~snip~ , when CO2 emits LW radiation it is at a frequency it cannot then reabsorb.
Cripes alive.

John Lish
February 26, 2009 12:02 pm

Steven,
the IPCC describes the forcing for a doubling of CO2 as 3.7 watts/m2. When I do the maths, that comes out at a fraction over 1 degree Kelvin. A tad lower than your claim of 1.2K.
The problem with this forcing is the still unexplained cooling period that started in the 40s through to the mid 70s. There just isn’t enough aerosol pollution to justify the masking claim by Jim Hansen and others.
However, the 3.7 watts/m2 is simply a hypothesis described by a one-shell model of the Earth’s atmosphere. If we add increased complexity to the model, the forcing for a doubling of CO2 reduces in effect. A lower forcing of say 2.3 watts/m2 gives approx. 0.6K for a doubling of CO2. That would explain more effectively the post-war dip in temperatures rather than relying on the aerosol handwaving.
There is also another logistical problem I have with the positive feedbacks claims. Atmospheric CO2 increases have a near instantaneous effect on temperature. We also know that CO2 effect on temperature is logarithmic so currently we have seen 60% of the forcing that a doubling of CO2 brings. So where are these positive feedbacks? There should be greater evidence of these occurring than the actual empirical data shows.
Also positive feedbacks build upon themselves. This stoppage in temperature rises cuts off that process. If natural variations have that effect then the positive feedbacks have to be considerably weaker than is assumed.

jeepndesert
February 26, 2009 12:10 pm

Sir, you are a complete tool of the international banking cartel and corporate fascists. They want carbon taxes not to fix the environment but to fund global government … to enslave the labor of the world, to steal the resources of the world without competition, and to bomb nations who don’t submit to their empire. Taxes do nothing but hurt the poor.
You, like all the other tools conveniently leave out the percentage of greenhouse effect from CO2 and other greenhouse gases. CO2 is roughly 3% of the total greenhouse effect. Around 0.2% is man-made CO2. CO2 is an insignificant greenhouse gas, especially in terms of man-made contribution. Water is the only significant greenhouse gas.
Furthermore, you leave out the impact of the sun spot activity, which is thoroughly studied, and it’s impact of warming/cooling on the solar system as a whole. Futhermore, you leave out that from the data that CO2 levels tend to follow warming rather than cause warmer.
Statistics and models are lies, lies, and damned lies. Any decent college professor in scientific modeling and advanced mathematics will tell you that.
~snip~

Richard
February 26, 2009 12:11 pm

Can anyone explain how the man-made portion of atmospheric CO2 is responsible for GLOBAL temperature change? The UN estimate of man-made CO2 is: 0.000348% by volume: “Mass of Global Atmospheric Gases” chart.
http://lce.folc.ca/2008/08/03/man-made-global-co2-emissions/
Then, factoring CO2 absorbtion of IR of about 8% spectrum yields the volume of atmosphere with sensitivity to thermal absorbtion is 0.00002785. Or, what have I done wrong?

Mike McMillan
February 26, 2009 12:11 pm

Peter (06:36:58) :
I’ve been led to understand that the CO2 released by man-made activities represents about 3% of the atmospheric CO2. Can anyone attest to the accuracy of that claim?
That comes from the IPCC, Climate Change 2001.
So I won’t attest to its accuracy.

David Ermer
February 26, 2009 12:17 pm

Time spent at stop lights is ttotal = n * tlight where n is the number of stop lights.
light absorbed by a column of air is Atotal = 1-exp(-(a1*c1+a2*c2+…)*l) where a is an absorption coefficient, c is a concentration and l is the length of the column.
So this is not a good analogy. Because the absorbed light is re-emitted and re-absorbed, I’m not saying that adding more GHG to a saturated system will not result in less energy emitted to space, but adding more should have a diminishing effect.

Steven Goddard
February 26, 2009 12:18 pm

Johnski,
You are correct about the narrow band of CO2 absorption/emission frequencies, but there are other greenhouse gases in the atmosphere besides CO2, which interact with each other. If you note from the spectral diagram above, H2O absorbs nearly continuously across the spectrum. No need to get snippy.

jeepndesert
February 26, 2009 12:19 pm

The facts that Al Gore’s carbon tax collection company doesn’t want you to see.
CO2 is roughly 3% of the total greenhouse effect. Around 0.2% is man-made CO2. CO2 is an insignificant greenhouse gas, especially in terms of man-made contribution. Water is the only significant greenhouse gas.
Furthermore, you leave out that oceans and volcanos release more CO2 than humans.
Furthermore, you leave out that CO2 is part of the life cycle.
Furthermore, you leave out the impact of the sun spot activity, which is thoroughly studied, and it’s impact of warming/cooling on the solar system as a whole.
Futhermore, you leave out that CO2 levels tend to follow warming rather than cause warmer.
Furthermore, you leave out that carbon taxes will not solve the problem but will fund global government and help big corporations to eliminate the competititon.
Furthermore, you leave out that polar bears can easily swim over 100 miles and swim as much as 300 miles. They hunt for seals and buluga whales.
Furthermore, you leave out that the ice caps are always melting and refreezing with the seasons.
Furthermore, you leave out that the solar system has a whole had been warming.
Furthermore, you leave out that the solar system and earth has cooled down due to lack of sun spot activity this past year.
Furthermore, you leave out that the government was caught making up temperature data.
Furthermore, you leave out that scientistics receive tons of funding by promoting global warming scares while skeptics don’t receive funding.
Statistics and models are lies, lies, and damned lies. Any decent college professor in scientific modeling and advanced mathematics will tell you that.

jeepndesert
February 26, 2009 12:21 pm

delete my post, i’m entering you into a database of obvious foundation funded criminals engaging in high crimes of fraud and corruption when the people wake up to the truth and tear down the new world order to stop global enslavement and global depopulation by the international banking cartel.
~snip~ [Please, if you disagree explain why, but don’t call other commenters liars here.]

Tom
February 26, 2009 12:22 pm

I agree with Steven Goddard that it is all about feedbacks. The case against the existence of positive feedback, however, is extremely strong. Positive feedback means an internal amplification factor greater than 1, which means a self reinforcing, runaway process. Best example of such a process is a chemical – or nuclear – explosion. There are many arguments against the Earth’s climate being a system that is controlled by positive feedback.
1., Historical evidence. There is no evidence in climate history, that temperature swings are being reinforced by positive feedback leading to runaway climatic changes. The most recent examle was the 1998 El Nino event, which generated an almost 1degree C spike in global temperature in less than one year. If positive feedback were to be present, the temperature would have kept climbing. Instead, after the El Nino was over, temperatures returned to their pre El Nino values.
2., Recent work by Dr. Roy Spencer, who, based on his research, in his recent congressional testimony stated, in front of Senator Boxer, that there is no positive feedback in the ( Earth’s ) climate. I guess he was willing to risk the charge of perjury.
3., Dr Hansen’ circular argument. He is clearly worried about a Venus like runaway heating caused by positive feedback. At the same time, he is postulating that positive feedback is already the operating principle of the Earth’s climate as witnessed by his projected climate sensitivity factor of 6.5, which implies existence of a strong positive feedback. If this were the case, we are already doomed. There is no magic “tipping point” . A positive feedback driven runaway process cannot be stopped any more than a nuclear explosion can be stopped halfway through the process.

maksimovich
February 26, 2009 12:22 pm

foinavon (10:14:41) :
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?
Kondratyev and Moskalenko 1983, 1984 These are in Russian,though translated extracts are in Houghton 1985
Essentially these are radiative/convection models similar to Ramanathan 1976,and as such more accurately ascertain for dissipation eg Landau and Lifshitz 1965(ie mathematically correct) as opposed to the empirical methodology used in GCM(where they “appeal” to a closure relation )
EG http://i255.photobucket.com/albums/hh133/mataraka/ramanathanco2x.jpg

David Corcoran
February 26, 2009 12:27 pm

Joel Shore (09:01:02) :

Do you have a cite for Hansen making such a claim?

I turned to Professor James Hansen, the director of Nasa’s Goddard Institute for Space Studies, whose climate calculations have proved to be more accurate than anybody else’s. He believes the melting of the Greenland ice cap being picked up by his satellites today, now, suggests we are facing a 25-metre rise in sea levels this century – which would drown Bangladesh entirely.
Bangladesh is set to disappear under the waves by the end of the century
Scary. Citation and a confirming letter from Dr. Hansen found here:
American Thinker
but wait:
Bangladesh landmass is growing
Not so scary.

Peter
February 26, 2009 12:30 pm

tmtisfree:

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.

The re-radiation doesn’t additionally warm the surface, but rather slows down the rate at which the surface loses heat – thereby keeping it warmer for longer than it would otherwise have been.
However, it only slows down the rate at which the surface loses heat by radiation – it doesn’t affect the rate of heat loss from conduction, convection or evaporation.

Steven Goddard
February 26, 2009 12:31 pm

David Ermer,
Like I said, this is not intended to be a qualitative article. The analogy is just to point out that more stoplights increase the difficulty of getting from point A to point B. The relationship with CO2 is of course not linear as you pointed out – a doubling of CO2 only impacts by 0.5% in temperature.

February 26, 2009 12:31 pm

How can anyone state that CO2 is a “greenhouse” gas when the atmosphere it is in NOT a greenhouse?
http://www.globalwarmingskeptics.info/

February 26, 2009 12:32 pm

The link in the comment was a mistake.It was supposed to be in the website box.Not related to my question.

Joel Shore
February 26, 2009 12:33 pm

gary gulrud says:

Where does this 341 W/m^2 come from? We are constantly told 1360 is the value.

The factor of 4 difference comes from the factor of 4 difference between the total surface area of the earth, which is 4*pi*r^2 and the earth’s cross-section as viewed from the sun (which is a circle of area pi*r^2). [Another way of thinking about this is that the 1360 W/m^2 is the intensity you would have if the sun were directly overhead; however, at any given time, half of the earth isn’t facing the sun at all and the other half all has the sun at some non-normal angle (except for the one point where it is directly overhead). So, averaged over the entire surface of the earth (or top of the atmosphere, if you want to get technical), the amount is 341 W/m^2.]

Steven Goddard
February 26, 2009 12:40 pm

jeepndesert,
Thanks for the listing as a Gore climate conspirator. I’m already listed as an oil company shill trying to destroy the climate. I’m just trying to get at the facts, whatever they may be. Maybe this year will be the hottest year ever, as Hansen predicted?
Speaking of which my UAH forecast for February is down from January at 0.24-0.26. I missed by 0.01 last month.

jeepndesert
February 26, 2009 12:41 pm

You inspired me to quickly write a great new blog post in response to the inconvenient truths you left out of your article.
http://newworldliberty.wordpress.com/2009/02/26/global-warming-is-a-hoax-quick-and-dirty/

Roger Knights
February 26, 2009 12:42 pm

Holy cow. Well, at least the issues have been laid on the table, and the points-in-dispute have been made apparent. I guess a mulligan is in order.

Peter
February 26, 2009 12:44 pm

Steve Goddard:

There isn’t a lot of LW arriving from the sun. Temperatures on the sun are too hot.

Not a lot, comparatively speaking, but still a substantial amount.

Joel Shore
February 26, 2009 12:44 pm

Tom says:

Positive feedback means an internal amplification factor greater than 1, which means a self reinforcing, runaway process.

No it doesn’t. If the positive feedback is sufficiently strong that the first order response is greater than the original effect (e.g., if the temperature response from feedbacks is greater than the bare response), then you have a diverging series and you are correct. However, if the positive feedback is weaker than this, then what you get is amplification, for example: 1 + 1/2 + 1/4 + 1/8 + 1/16, an infinite series that converges to 2.

1., Historical evidence. There is no evidence in climate history, that temperature swings are being reinforced by positive feedback leading to runaway climatic changes. The most recent examle was the 1998 El Nino event, which generated an almost 1degree C spike in global temperature in less than one year. If positive feedback were to be present, the temperature would have kept climbing. Instead, after the El Nino was over, temperatures returned to their pre El Nino values.

Your statement is erroneous for the reasons that I noted above. In fact, the evidence from past historical events such as the eruption of Mt Pinatubo and the ice age – interglacial oscillations is the main line of evidence leading to estimates of what the feedbacks and resulting climate sensitivity is. And, most scientists have concluded that the sensitivity is 2-4.5 C for a doubling of CO2, which corresponds to about a doubling to a quadrupling of the “bare” response by net positive feedbacks.

2., Recent work by Dr. Roy Spencer, who, based on his research, in his recent congressional testimony stated, in front of Senator Boxer, that there is no positive feedback in the ( Earth’s ) climate. I guess he was willing to risk the charge of perjury.

It is not perjury if he sincerely believes this, which I think he does. However, that doesn’t mean that he is right.

3., Dr Hansen’ circular argument. He is clearly worried about a Venus like runaway heating caused by positive feedback. At the same time, he is postulating that positive feedback is already the operating principle of the Earth’s climate as witnessed by his projected climate sensitivity factor of 6.5, which implies existence of a strong positive feedback. If this were the case, we are already doomed. There is no magic “tipping point” . A positive feedback driven runaway process cannot be stopped any more than a nuclear explosion can be stopped halfway through the process.

Again, you are confusing the issues of positive feedback, true runaway, and also the possibility of tipping points. These are three distinguishable things. I think that most climate scientists would say that a net positive feedbacks is very likely, tipping points are quite possible (given the historical record) but we don’t know where they are, and an actual runaway is unlikely (although Hansen would claim otherwise…if we really don’t restrain ourselves at all in burning fossil fuels).

February 26, 2009 12:44 pm

A positive feedback…that´s alchemy. We need some to overcome financial crisis. Kind of Keynesian meteorology!!

February 26, 2009 12:45 pm

Steven,
I appreciate the attempt to find some common ground on what we agree on and where uncertainties remain. I agree that the radiative forcing of CO2 is one of the areas where we can be fairly confident in our projections, but that overall climate sensitivity (taking into account various feedbacks) is where the major debate lies.
Unfortunately, it seems by the comments that many folks have reached a point where any suggestion of the role of CO2 in warming the planet is dismissed out of hand. A bit of common ground would go a long way toward having a more constructive dialogue between both sides of the climate debate (which, as an aside, is why I enjoy Lucia’s place; no need over there to waste time arguing with people who conflate CO2 flux with CO2 stocks, for example).

February 26, 2009 12:46 pm

Positive feedback: the perpetual movement

James Griffiths
February 26, 2009 1:05 pm

Joel Shore says: (albeit a quote from someone else):
“The surface of the Earth is warmer than it would be in the absence of an atmosphere because it receives energy from two sources: the Sun and the atmosphere.”
I suppose that should be quantified (at least as I understand it)
The atmosphere (and the oceans) cool the surface while the sun is shining upon it, and prevent heat from leaving as quickly it might otherwise when the sun is not shining on it, thereby maintaining a mean temperature that we calculate is higher than might otherwise be the case.
In my interpretation, that puts the bulk of the mean difference as happening on dark surfaces of the earth when no SW radiation is incoming. Certainly, it seems plausible that LW radiative heating may have a stronger effect when there is no higher energy source of radiation entering the system., but it seems a stretch to attribute the warming that is claimed to it.
As the oceans have a huge thermal inertia compared to the atmosphere, and the surface temperatures are definitely not as hot as they would be without an atmosphere, I wonder why the atmosphere is the prime candidate for “carrying” the heat through the nighttime hours. Surely the medium that loses least energy over a certain period when an incoming source is terminated would be a more reasonable “culprit” for maintaining an average temperature in a system.
I am no expert, I am just applying my own twisted logic to the argument. I’m perfectly happy to be educated by anyone who knows better, even if it involves an egg/face incident.

Ray
February 26, 2009 1:08 pm

Without the sun to feed it, there is no feedback! Like pretty much all Law of nature, we should be dealing with an exponential relationship and nit just some “constant” number to represent the feedback.

Joel Shore
February 26, 2009 1:09 pm

Stevo says:

Oh, and the tropical troposphere ‘hotspot’ is a result of the water vapour feedback mechanism predicted to treble global warming. It’s absence is a blow not to the validity of CO2 greenhouse physics, but to the postulated feedbacks.

Sort of…but a little clarification is in order. If the hotspot in the tropical atmosphere is really absent (which I think is doubtful but the observational data is inconclusive at this point) then the most direct consequence of this is that the lapse rate feedback in the models, which is a NEGATIVE feedback that counters part of the positive water vapor feedback, is absent. So, the most direct consequence would be to imply that there should be more warming than the models predict. [The rough logic for this is that the place in the atmosphere that has to heat up a certain amount in order to put the earth back in radiative equilibrium is the upper troposphere. So, if the tropical upper troposphere is not heating more than the surface (as the models now predict), then the surface would have to heat up more in order to get the tropical troposphere heated up the necessary amount.]
Now, one can argue that if the models are not getting these convective aspects correct, they are likely wrong on the water vapor feedback too. However, since we have some independent observational verification that the upper troposphere is moistening approximately as expected (from Brian Soden’s work and also Dessler’s work), this seems unlikely.

February 26, 2009 1:29 pm

Princeton Physicist Tells Congress Earth in ‘CO2 Famine’ — Increase ‘Will Be Good for Mankind’
http://www.businessandmedia.org/articles/2009/20090225213407.aspx

Robert Wood
February 26, 2009 1:45 pm

Stevo (11:09:20) :
As good an explanation as I’ve seen.

gary gulrud
February 26, 2009 1:54 pm

“The factor of 4 difference comes from the factor of 4 difference between the total surface area of the earth, which is 4*pi*r^2 and the earth’s cross-section as viewed from the sun (which is a circle of area pi*r^2). ”
Thank you.

james griffin
February 26, 2009 1:55 pm

It may well be a good explanation of the AGW theory and clearly greater minds than mine will debate and argue for a long time to come.
However the article at this stage smacks of the desperation of the AGW’s.
Those in the know do not dismiss the basic theory…it is the outcome that is the sticking point.
As Prof Bob Carter said in his presenatation in Sept 2007…they put in the positives of their argument but not the negatives.
There has been no warming for around 10 years and the Aqua satellite did not find the hot spots in the upper atmosphere it should have done.
The Polar Ice Caps are returning and the changes we are experiencing from the change in the sun cycle are clearly at odds with the dire warnings of the AGW theory.
In fact the BBC even published an article from the Guardian regarding a recent admission by the Hadley centre that some of the more catastrophic outcomes of the increased CO2 levels are somewhat wide of the mark.
Having no scientific training I just use commonsense.
References to James Hansen being “correct” are in fact part of the admission that although his theory is correct…his wild predictions on the eventual outcome are not.
Good luch all of you who are qualified to debate this…we await the outcome with interest.

Drew Latta
February 26, 2009 2:00 pm

What in the world are the units on the x-axis of the second figure (1st plot with estimated temperature vs. something?)?
Huge pet peeve… not labeling axes!!

Simon Evans
February 26, 2009 2:02 pm

Paddy (11:52:11) :
Of course the “Earth was just fine” millions of years ago when CO2 levels were much higher. It was just fine when temperatures were higher or lower, just fine when sea levels were higher or lower, and so on. The changes from one state to another, however, have gone along with the evolution of life on the planet. In the case of rapid changes (which might be measured on the scale of tens or hundreds of thousands of years), some such changes are associated with mass extinction events. We’re currently considering the impact of changes on a century scale or less. The concerns are not for whether the planet will surivive (it will) but whether we can support our current population and its geographical distribution, along with out current biodiversity.

jae
February 26, 2009 2:03 pm

Hasit been, 11:07:20
“Wide Temperature Range
Temperatures in arid areas may get as high as 55 degrees C during the day and as low as 10 degrees C during the night. The drop in temperature at night occurs rapidly and will chill a person who lacks warm clothing and is unable to move about. The cool evenings and nights are the best times to work or travel. If your plan is to rest at night, you will find a wool sweater, long underwear, and a wool stocking cap extremely helpful. “
These types of accounts are what cause the MYTH of the frigid desert night and super hot days. This ONLY occurs at high elevations (and high latitude). It does NOT occur at low altitude deserts below 45 N/S latitude. In fact, It has nothing at all to do with deserts; it occurs at high elevations EVERYWHERE, not just in deserts. Look, for example, at Alamosa, CO, which is at about 2300 m elevation. It is not considered a desert, because it gets more than 5 inches of precipitation per year (mainly snow there). But a typical July day will vary from 27.8 C during the day to 8.8 C at night, for a diurnal variation of 19 C. Here you do need a coat at night! But it is no worse in any high altitude desert. For example, look at Tonopah, NV, which is at 1653 m elevation (even somewhat lower than Alamosa). Here the average high in July is 32.8 C and the average low is 13.6 C, for about the same diurnal variation. Now look at a typical low-elevation desert, like Daggett, CA, 588 m elevation. Here the variation is from 39.9 to 23.3 C, for a diurnal variation of 16.6 C. (The average relative humidities for these locations are 56 (Alamosa), 26 (Tonopah), 24 (Daggett)).
Also note that the LOW temperature of 23.3 C in Daggett is still higher than the average low temperature for Atlanta (20.8). You do not have to dress warmly for the night-time in July in either Atlanta or Daggett.
Data at http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/sum2/state.html

Roger Knights
February 26, 2009 2:05 pm

OT: Bloomberg story: “Obama Plan Has $79 Billion From Cap-and-Trade in 2010”
http://www.bloomberg.com/apps/news?pid=20601087&sid=akMqKTP2B1wo&refer=home
Sample quote:
“President Barack Obama’s budget plan assumes $78.7 billion in revenue in 2012 from the sale of greenhouse-gas emission permits to polluters, putting pressure on Congress to pass legislation by early next year.
“A “cap-and-trade” program would generate a total of $645.7 billion by 2019, according to the budget blueprint Obama sent to Congress today. Initial funds would be used to invest in “clean” energy, help finance Obama’s tax credit for workers as well as offset higher energy costs for low- and middle-income people and clean up costs for small businesses.
“The budget calls for the Environmental Protection Agency to get $19 million to begin setting up an inventory of greenhouse- gas emissions”

jae
February 26, 2009 2:15 pm

Joel Shore, 12:44:28
“I think that most climate scientists would say that a net positive feedbacks is very likely, tipping points are quite possible (given the historical record) but we don’t know where they are, and an actual runaway is unlikely (although Hansen would claim otherwise…if we really don’t restrain ourselves at all in burning fossil fuels).”
If you believe this, I have a bridge to nowhere to sell you…. 🙂
Seriously, I don’t think a significant positive water vapor feedback is possible for the following reasons. Go ahead and assume that a doubling of CO2 causes a 1.2 C rise in temperature. It is trivial to show with the Classius-Clapeyron equation that this increase in temperature can cause, at most, an 8% increase in evaporation of water. Like CO2, the relationship between concentration and radiation is logarithmic. MODTRAN shows this, if you play with the water vapor concentration and leave everything else constant. According to MODTRAN a doubling of water vapor would increase radiation by about 15 w m-2 (first doubling). Thus, an increase of 8% water vapor would amount to only (0.08)(15) = 1.2 wm-2. Negligible.

jae
February 26, 2009 2:16 pm

Dammit. The above should read: “Like CO2, the relationship between concentration and radiation FOR WATER VAPOR is logarithmic.”

lgl
February 26, 2009 2:17 pm

Leif
Where do people get these ideas from? Googling the internet?
No ,this is textbook knowledge, which you usually embrace, why not this time?

David Porter
February 26, 2009 2:17 pm

foinavon (10:14:41) :
As usual you disparage all the previous theories and replace them with the newly concocted papers from the early 2000 to 2008. That makes me very suspicious and it should make you suspicious also. The fact that it doesn’t, speaks volumes to me. You should ask yourself how the font of all knowledge appears only in the last eight to nine years.
On the theme that you think life began only nine years ago you may be aware that there was a medieval warm period and a little ice age. Outside of your own fledgling scientific field all other facets of science acknowledged these historical periods. Unfortunately these periods run contrary to the CO2 thesis. Then along came Mann and his bent hockey stick and the rewrite of historical temperature records commenced. Even though Mann’s work has become the most discredited piece of climate science, along comes a whole raft of other studies purporting to show variants of the hockey stick. Naturally all of these studies are post Mann. None of them pre-date him. Coincidence? Not likely.
And Anthony, it’s not a question of over analysing. Foinavon will argue black is white as long as it is in defense of that beloved molecule, CO2.

February 26, 2009 2:17 pm

When I was in college, we were taught how to solve equations with two or three variables. We applied this math to try and figure out how electric motors really worked so we could predict horsepower output and efficiency. When the professor started writing down all the variables (about 15 or twenty in all), we found it impossible to calculate the output. Of course, the professor already knew this. It got worse when we tried to figure out how radio antennas really work (some configurations are pretty exotic). Even the experts admit that some of this is black art with trial and error because of all the variables and our lack of understanding of certain aspects of electromagnetics.
So after reading all this back and forth. I started thinking of the THOUSANDS (if not more) of variables far beyond the very few mentioned in the arguments in the comments to this posting).
There is no way any supercomputer can be set up to model all the variables on the Earth and coming at us from the sun, etc.
Mr. Goddard’s simplistic post on the greenhouse effect doesn’t do anything to show CO2 affects us at all, and is a disappointing primer no better than telling my son that the reason a car works is because you put gas in it and push on the pedal. To understand it, you need to know what’s under the hood.
So how did we finally figure out the horsepower and efficiency of the motor, or the effectiveness of a radio antenna? We tried it out, tweaked stuff, recorded data and drew conclusions. We dropped the idea of calculating or modeling how the stuff worked.
So back to the Greenhouse: I simply watch the satellite data and see the temperature statistics over time. The Arctic icecap did not melt last summer, and it doesn’t look like it will before I’m gone. And no one seems to be able to find arguable evidence of the oceans rising at historic tidal water marks at various locations around the Earth from these past centuries.
Sometimes observation over time, is better than trying to predict 50 years into the future with math we just can’t solve.

Peter
February 26, 2009 2:23 pm

Joel Shore:

However, if the positive feedback is weaker than this, then what you get is amplification, for example: 1 + 1/2 + 1/4 + 1/8 + 1/16, an infinite series that converges to 2.

That being the case, and I agree btw, how can they predict temperature increases of several times what can be attributable to CO2 forcing?

AlexB
February 26, 2009 2:28 pm

Steve,
Looking at three planets and saying that as greenhouse gas concentration increases so does temperature does not really settle the issue for me I’m affraid. The proxy record of fluctuating CO2 and temperature indicates quiet clearly to me that radiative heat transfer is by far not the dominant heat transfer mechanism in the earths atmosphere. Increased temperature increases verticle wind shear. To put it in terms of your car analogy CO2 would add an extra traffic light on the road between your school and place of work, but then verticle wind shear would go and put an expressway between them.

February 26, 2009 2:28 pm

Colonel Sun (10:14:32) :
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
The experiment is not about replicating the atmosphere, but empirically evaluating the efficacy of CO2 as a greenhouse gas relative to the atmosphere.
As for Venus and Mars, the 1/r^s of solar radiation is the dominant effect.

David Porter
February 26, 2009 2:29 pm

Joel Shore (12:44:28) :
“No it doesn’t. If the positive feedback is sufficiently strong that the first order response is greater than the original effect (e.g., if the temperature response from feedbacks is greater than the bare response), then you have a diverging series and you are correct. However, if the positive feedback is weaker than this, then what you get is amplification, for example: 1 + 1/2 + 1/4 + 1/8 + 1/16, an infinite series that converges to 2.”
Not again Joel please. It’s getting like Ground Hog day.

Mark_0454
February 26, 2009 2:29 pm

Joel Shore 12:44:28
“I think that most climate scientists would say that a net positive feedbacks is very likely,….”
I watched the you-tube debate at the JLF foundation. It was my impression that experimental evidence at this point is that feedback is negative. No evidence for positive feedback.

Simon Evans
February 26, 2009 2:32 pm

jae (14:15:27) :
Thus, an increase of 8% water vapor would amount to only (0.08)(15) = 1.2 wm-2. Negligible.
Accepting your figures for now, that’s equal to 75% of the current net anthropogenic forcing. Why negligible? CO2 doubling is likely to be reached by the 2050s at current rates. So, to put it in simplified terms then, by your calculations we are looking at 1.2C + 0.9C = +2.1C by the 2050s. How ‘negligible’ is that?

Gerald Machnee
February 26, 2009 2:37 pm

Steven Goddard (10:04:26) :
**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
Sorry I meant to say that fog blocks SW (not LW) which is the dominant factor during the day. LW blocking is more interesting at night.**
Steve, you have it backwards in the first sentence. The cold air over the ocean does not cause fog because it would get heated and develop into convective cloud. That is how you get showers or snow showers in the winter further north. Advection fog develops when warm moist air moves over cooler water. Radiation fog develops over land at night when land cools due to LW radiation.
SW radiation heats the water, but because it penetrates up to hundreds of feet the daily change can only be a fraction of a degree. It takes a long time to heat water. The Great Lakes take a couple of months to get to 15 to 20 degrees. There is a similar effect for cooling. Water will cool by emitting LW radiation, but it also emits from the depths so it can only cool a fraction of a degree overnight and therefore radiation fog cannot form over water. This is why the Great Lakes do not freeze during an average winter. Lake Erie being the most shallow will freeze first.
On the other hand LW radiation emitted from land can drop the temperature 20 to 30 degrees overnight(on a clear night).
Cloud cover will reradiate the LW back down and slow the cooling.

February 26, 2009 2:42 pm

That should be 1/r^2

jae
February 26, 2009 2:44 pm

Simon: That’s WATTS, not degrees. 3.7 watts translates to 1.2 C; so 1.2 watt translates to only 0.39 C. And that’s a worst-case scenario.

John Galt
February 26, 2009 2:45 pm

jae:
Death Valley is about as low a desert as you can get (it’s below sea level). In July, the average temperature range is for the high is 115 with an average low of 86, according to the weather channel.
Disclaimer: I don’t know exactly where the official temperatures are recorded in Death Valley. Death Valley is about as dry and barren as you can get, and is surrounded by mountains on all sides. There is no urbanization there, but official temps could be affected by land use changes near the weather station.
There should be comparable high desert sites nearby for comparison. What’s the altitude of Baker, CA? It’s not far from Death Valley (and is home to the world’s largest thermometer, btw) and except for possible local siting issues, there isn’t any urbanization to speak of in Baker, either. Weather.com shows the July average ranges from 108 to 76.