(Note: this originally published on Dr. Spencer’s blog on April 25th, and I asked if I could reproduce it here. While I know some readers might argue the finer points of some items in the list, I think it is important to keep sight of these. – Anthony)
by Roy W. Spencer, Ph. D.
There are some very good arguments for being skeptical of global warming predictions. But the proliferation of bad arguments is becoming almost dizzying.
I understand and appreciate that many of the things we think we know in science end up being wrong. I get that. But some of the alternative explanations I’m seeing border on the ludicrous.
So, here’s my Top 10 list of stupid skeptic arguments. I’m sure there are more, and maybe I missed a couple important ones. Oh well.
My obvious goal here is not to change minds that are already made up, which is impossible (by definition), but to reach 1,000+ (mostly nasty) comments in response to this post. So, help me out here!
1. THERE IS NO GREENHOUSE EFFECT. Despite the fact that downwelling IR from the sky can be measured, and amounts to a level (~300 W/m2) that can be scarcely be ignored; the neglect of which would totally screw up weather forecast model runs if it was not included; and would lead to VERY cold nights if it didn’t exist; and can be easily measured directly with a handheld IR thermometer pointed at the sky (because an IR thermometer measures the IR-induced temperature change of the surface of a thermopile, QED)… Please stop the “no greenhouse effect” stuff. It’s making us skeptics look bad. I’ve blogged on this numerous times…maybe start here.
2. THE GREENHOUSE EFFECT VIOLATES THE 2ND LAW OF THERMODYNAMICS. The second law can be stated in several ways, but one way is that the net flow of energy must be from higher temperature to lower temperature. This is not violated by the greenhouse effect. The apparent violation of the 2nd Law seems to be traced to the fact that all bodies emit IR radiation…including cooler bodies toward warmer bodies. But the NET flow of thermal radiation is still from the warmer body to the cooler body. Even if you don’t believe there is 2-way flow, and only 1-way flow…the rate of flow depends upon the temperature of both bodies, and changing the cooler body’s temperature will change the cooling rate (and thus the temperature) of the warmer body. So, yes, a cooler body can make a warm body even warmer still…as evidenced by putting your clothes on.
3. CO2 CANT CAUSE WARMING BECAUSE CO2 EMITS IR AS FAST AS IT ABSORBS. No. When a CO2 molecule absorbs an IR photon, the mean free path within the atmosphere is so short that the molecule gives up its energy to surrounding molecules before it can (on average) emit an IR photon in its temporarily excited state. See more here. Also important is the fact that the rate at which a CO2 molecule absorbs IR is mostly independent of temperature, but the rate at which it emits IR increases strongly with temperature. There is no requirement that a layer of air emits as much IR as it absorbs…in fact, in general, the the rates of IR emission and absorption are pretty far from equal.
4. CO2 COOLS, NOT WARMS, THE ATMOSPHERE. This one is a little more subtle because the net effect of greenhouse gases is to cool the upper atmosphere, and warm the lower atmosphere, compared to if no greenhouse gases were present. Since any IR absorber is also an IR emitter, a CO2 molecule can both cool and warm, because it both absorbs and emits IR photons.
5. ADDING CO2 TO THE ATMOSPHERE HAS NO EFFECT BECAUSE THE CO2 ABSORPTION BANDS ARE ALREADY 100% OPAQUE. First, no they are not, and that’s because of pressure broadening. Second, even if the atmosphere was 100% opaque, it doesn’t matter. Here’s why.
6. LOWER ATMOSPHERIC WARMTH IS DUE TO THE LAPSE RATE/ADIABATIC COMPRESSION. No, the lapse rate describes how the temperature of a parcel of air changes from adiabatic compression/expansion of air as it sinks/rises. So, it can explain how the temperature changes during convective overturning, but not what the absolute temperature is. Explaining absolute air temperature is an energy budget question. You cannot write a physics-based equation to obtain the average temperature at any altitude without using the energy budget. If adiabatic compression explains temperature, why is the atmospheric temperature at 100 mb is nearly the same as the temperature at 1 mb, despite 100x as much atmospheric pressure? More about all this here.
7. WARMING CAUSES CO2 TO RISE, NOT THE OTHER WAY AROUND The rate of rise in atmospheric CO2 is currently 2 ppm/yr, a rate which is 100 times as fast as any time in the 300,000 year Vostok ice core record. And we know our consumption of fossil fuels is emitting CO2 200 times as fast! So, where is the 100x as fast rise in today’s temperature causing this CO2 rise? C’mon people, think. But not to worry…CO2 is the elixir of life…let’s embrace more of it!
8. THE IPCC MODELS ARE FOR A FLAT EARTH I have no explanation where this little tidbit of misinformation comes from. Climate models address a spherical, rotating, Earth with a day-night (diurnal) cycle in solar illumination and atmospheric Coriolis force (due to both Earth curvature and rotation). Yes, you can do a global average of energy flows and show them in a flat-earth cartoon, like the Kiehl-Trenberth energy budget diagram which is a useful learning tool, but I hope most thinking people can distinguish between a handful of global-average average numbers in a conceptual diagram, and a full-blown 3D global climate model.
9. THERE IS NO SUCH THING AS A GLOBAL AVERAGE TEMPERATURE Really?! Is there an average temperature of your bathtub full of water? Or of a room in your house? Now, we might argue over how to do the averaging (Spatial? Mass-weighted?), but you can compute an average, and you can monitor it over time, and see if it changes. The exercise is only futile if your sampling isn’t good enough to realistically monitor changes over time. Just because we don’t know the average surface temperature of the Earth to better than, say 1 deg. C, doesn’t mean we can’t monitor changes in the average over time. We have never known exactly how many people are in the U.S., but we have useful estimates of how the number has increased in the last 50-100 years. Why is “temperature” so important? Because the thermal IR emission in response to temperature is what stabilizes the climate system….the hotter things get, the more energy is lost to outer space.
10. THE EARTH ISN’T A BLACK BODY. Well, duh. No one said it was. In the broadband IR, though, it’s close to a blackbody, with an average emissivity of around 0.95. But whether a climate model uses 0.95 or 1.0 for surface emissivity isn’t going to change the conclusions we make about the sensitivity of the climate system to increasing carbon dioxide.
I’m sure I could come up with a longer list than this, but these were the main issues that came to mind.
So why am I trying to stir up a hornets nest (again)? Because when skeptics embrace “science” that is worse that the IPCC’s science, we hurt our credibility.
NOTE: Because of the large number of negative comments this post will generate, please excuse me if I don’t respond to every one. Or even very many of them. But if I see a new point being made I haven’t addressed before, I’ll be more likely to respond.
* If you read the thread at Roy’s blog, you will find people arguing against pretty much all 10 of these point.
* If you read the “Steel Greenhouse” thread here at WUWT, you will see many of these arguments. (or in pretty much any other thread here at WUWT that deals with the physics of the GHE).
* If you read pretty much anything at “Principia Scientific International” you will see these. (But I would not suggest it since it will drive more traffic there).
* A blog which will remain nameless just posted a ‘rebuttal’ of all 10 of Roy’s points!
So yes these arguments DO materialize in many climate blogs. It may be a small total number of posters, but they are prolific!
1. elmer says:
May 1, 2014 at 6:58 am
In response to number 4. “CO2 COOLS, NOT WARMS, THE ATMOSPHERE.” I agree with the doctor but if increased CO2 replaces other more effective greenhouse gases such as water vapor or Methane wouldn’t that cause cooling?
Molecule for molecule, water vapor is NOT a more effective greenhouse gas than CO2. In fact, molecule per molecule, CO2 is 30 times as effective a greenhouse gas as H2O. The only reason water vapor carries most of the greenhouse effect is that there’s a whole lot more of it, several hundred times more, than CO2. But if you’re talking about one “replacing” the other in the atmosphere, then you’re talking molecule for molecule (or at least gram for gram or liter per liter, I don’t know which unit you would use, but it wouldn’t make a whole lot of difference either way). You’d be replacing one unit (molecule, gram, liter?) of a gas with a low greenhouse potential with the same unit of a gas with 30 times as much greenhouse potential. So molecule for molecule, 29 times more warming.
Now, methane IS a more effective greenhouse gas (molecule for molecule, gram for gram, liter for liter) than CO2, so if you could specifically replace only the methane with CO2, then yes, more CO2 would cause cooling. But you don’t get to pick and choose; it’s all random. And given that there is several million times as much water vapor in the atmosphere as methane, chances are it’s water vapor you’re replacing.
Futhermore, over 95% of our atmosphere is not greenhouse gasses at all. It’s Nitrogen and Oxygen. If the CO2 replaces anything, it’s more likely to replace Nitrogen than anything else, with Oxygen a close second and water vapor a distant third. Since Nitrogen and Oxygen are not greenhouse gasses at all, 95% of the CO2 molecules would be replacing molecules that didn’t have any greenhouse potential at all, and 4+% would be replacing molecules (water vapor) with a positive but much lower greenhouse potential than the CO2. So, altogether, over 99% of the CO2 would be replacing gasses with LESS greenhouse potential than the CO2 itself (and most of the remaining CO2 molecules would be replacing other CO2 molecules, for no difference). Only a small fraction of a percent of the CO2 would replace gasses (like methane) with more greenhouse potential than the CO2 itself.
Moreover, I’m not entirely sure that CO2 “replaces” other gasses in the atmosphere like that. I mean it’s not like there’s some limit on how many molecules, grams, or liters of gas our atmosphere can contain. Seems to me any additional CO2 just gets ADDED to the gasses already there. Oh sure, burning fossil fuels, while putting CO2 into the atmosphere, removes O2 from the atmosphere (though as shown in the last paragraph, that’s not a good thing). But the total weight of the CO2 produced is more than the weight of the O2 consumed, so without question, burning fossile fuels adds mass to the atmosphere, and I don’t think there’s some built-in process to remove something else to keep the total atmospheric mass constant.
Regards,
Trevor
Don Easterbrook says:
May 1, 2014 at 8:27 am
“…but it isn’t the only cause of increased CO2.”
True. It is not temperature alone. But, it is a temperature dependent process. The slope of the rate of change of CO2 curve at that link is fully accounted for by the temperature relationship. However, the rate of emissions also has a slope. There is little to no room for it. The slope is already accounted for by the temperature relationship. Hence, human induced emissions cannot be the controlling factor in atmospheric CO2.
My currently preferred explanation is that it is an elevated concentration of CO2 emerging in upwelling ocean waters, whose outgassing is being modulated by changing temperatures.
rgbatduke says:
May 1, 2014 at 8:58 am
I actually have a couple of questions generated from the list above — serious ones I hope.
First, pressure broadening. Yes, I understand exactly where pressure broadening comes from — it is associated with the phase interruption brought about by collisions that alter the shape/width of the IIRC Lorentzian associated with any given emission line. The collisions don’t add energy (on average) but the phase interruption ensures that the fourier transform of the emission line gets fatter. No problem.
My problem is that I cannot for the life of me understand why pressure broadening should depend in any way on the partial pressure of CO_2. It should depend on the pressure, to be sure, and the density, without any doubt and the temperature — basically on the mean free time between collisions. Collisions with anything, not just CO_2 – CO_2 collisions.
Now is somebody asserting the increasing atmospheric CO_2 from 300 ppm to 600 ppm is going to increase the absolute pressure of the atmosphere anywhere in any measurable way? Or am I very confused about pressure broadening and does it in fact depend on partial pressure of particular species? Because this is one thing I just don’t get…
You are indeed confused about pressure broadening, different gases have different broadening coefficients, in particular the ‘self broadening’, in this case of CO2 by CO2. Check out references on line by line calculations such as HITRAN, Spectracalc covers it I think:
http://www.spectralcalc.com/info/CalculatingSpectra.pdf
ps..
A great effort to ENFORCE CONSENSUS among non CAGWer, of Roy’s opinion s about the issue.
It seems to me that the single individual greatest point of contention is number 9 concerning the global average temperature. Several people have made good analogies and inspired by one of them. I have measured all 10 rooms in my house (which can equate to Koppen climate zones). They ranged from 9.2C to 18.5C (fuel is too expensive to heat every room, whilst solar gain has made a difference to a couple of them)
The average was 14.5C although that was not the actual temperature of any of the rooms.
What does that average tell us? Is it useful? Is it meaningful? Can we learn anything from it?
Is it merely hiding the fact that some of the rooms are distinctly chilly whilst others are just about warm enough?
An average global temperature is merely hiding the nuances that would show that some parts of the world are reacting differently to other parts, in as much some are cooling whilst others warm. Why they are reacting differently is not being examined
I’m still not convinced by any of the arguments that, whilst it may be technically possible to come up with a global average (although that seems debatable due to the lack of consistency) it is necessarily meaningful or helpful.
tonyb
Show us the empirical data proving that a ‘greenhouse effect’ caused by CO2 exists.
9. THERE IS NO SUCH THING AS A GLOBAL AVERAGE TEMPERATURE
Some people are interpreting this as ‘correct temperature’ or ‘ideal temperature.’ That is not the same as ‘average temperature.’ The average temperature today, this year, or the last decade is what it is – average – whether useful or not. During the PETM global temperature rose by 6 °C. Since the end of the Little Ice Age temps have risen by ~0.8C.
I do think it’s useful to give a link to at least one example of someone actually making one of the top ten skeptical arguments. So here’s a comment from someone that argues for No. 6 as well as No. 2: http://rankexploits.com/musings/2014/the-fullness-of-time-doug-cotton-comments-unveiled/#comment-129079 There are many other comments on the linked thread.
In the end though , given the magnitude of all the other competing factors around it, what do you estimate c02’s addition to the temp at? If its close to 0, then what are we arguing over. The fact is its part of the far bigger blanket ( I think greenhouse is a non descriptive term.. its a blanket of gasses that are most dense near the earths surface and therefore the interaction is something that is up for constant debate. A lowering of 1C of ocean water at 80 has far more effect on the global mixing ratios than a rise of 10 degrees where air is bone dry and is near 0F) I estimate c02 is effectively boxed into a .4 to .7C “responsibility” if you will compared to the other blanket gasses that make up the estimated 33c of warming that make the planet livable. But my point is that in the circular firing squad this has become, next to everything else, anyone wish to estimate exactly how much of disaster this causing. And given the ideas I spouted when the PDO flipped and are clearly seen in the NCEP recreation of temperatures in the past 10 years, is a point here that without co2 we would be descending into an ice age. Which is my point to Dr Spencer. Over the years, everything you have said IMO is spot on. I have changed ideas based on what you teach. However, YOU HAVE TO TELL ME what the result is. I need you to quantify it. Its like any argument I have, okay make your forecast. Tell me what the contribution is. Are you saying without this increase.. and yes its as fast as its ever been but its still tiny compared to all around it, are you saying without it we would be heading down faster than what we see here since the PDO flip
http://models.weatherbell.com/climate/cfsr_t2m_2005.png
The point is not to challenge your points Roy, its to say WHATS THE FORECAST! My neanderthal ideas say weigh everything, assign a value, then make the forecast. Given what I know, the role co2 plays is so tiny that we are like theologians arguing over how many angels can be stuck on the head of the needle. My bottom line from 07 remains. that by 2030 we return to the measurements of sea ice and temps we were at in 1978 the start of the satellite era and start of the warm PDO. When the AMO flips that should tell the tale. The wild card of solar activity and stochastic events form the triple crown of climate. But perhaps its because of my limited education, bs PSU, that I cant grasp the idea that this small amount of gas is going to be of any major consequence in the global climate given the magnitude of all around it . I think that is also the screaming message of the Dr Vincent Grays chart
http://wattsupwiththat.files.wordpress.com/2013/06/co2_temperature_historical.png
and Dr William Grays Holy Grail (IMO)
http://typhoon.atmos.colostate.edu/Includes/Documents/Publications/gray2012.pdf
All these things you have said, and again I am not as versed as you, look correct to me, But in the realm of the planetary climate and the variance that comes natural to it, does it make a difference and can it be quantified. If not, its effect as close to 0 as it can be, so close that all of us in this fight are just useful tools of an agenda that really couldnt give a hoot about it anyway
[Thank you. Mod]
Has anyone calculated a margin of error for global average temperature as currently calculated? I suspect the margin of error is greater than 1C, which would mean that the 0.8C of global warming estimated to have occurred over the past century is within the margin of error or very close to it. That doesn’t mean it hasn’t warmed, just that we can’t say for sure based on the data we have.
On averages
Last winter (say 29th of december, I don’t remember) I was sitting in the garden on the southeastern side of my house. Eleven o’clock in the morning. The sun is shining. The thermometer hanging there shows friendly 19 degrees celsius.
The other side of the house, in the shade till afternoon, shows -3 degrees celsius.
So, please, what’s the average temperature of my garden?
If the so-called “scientists” of the IPCC could prove their theories, they wouldn’t have to worry about skeptics, would they?
Anthony’s site is now heading the same way of most alarmist sites,
Blocking and deleting dissenting views.
This is how CONSENSUS works.
On greenhouse effect
I don’t really understand how the greenhouse effect works. But consider the moon. 100 degrees on the dayside. -100 degrees on the nightside.
So our atmosphere (somehow) cools during the day and keeps warm at night. Even more so when cloudy.
This site is now heading the same way of most alarmist sites,
Blocking and deleting dissenting views.
This is how CONSENSUS works.
[?? Mod]
… So, where is the 100x as fast rise in today’s temperature causing this CO2 rise? C’mon people, think. But not to worry…CO2 is the elixir of life…let’s embrace more of it!..
I DO like to see this point being made. I have lost count of the number of times someone has said to me: “Even if there’s no Global Warming, cutting CO2 output must surely be good?”
I want to start a “500 PPM” club, dedicated to the improvement of all growing plants…
Its simple lb,
This thing they are calling the greenhouse effect is actually an atmospheric gravity effect.
The atmospheric gradient allows the retention of heat in the lower layers.
Moon has no atmosphere.. very little gravity effect
Earth has a semi-tenuous atmosphere, so a variable gravity effect
Venus has a massive atmospheric gravity effect and basically retains the same temp over its whole surface even on the non-sunwards side.
I think that Dr Roy’s post is quite useful, but maybe overly prone to dichotomizing the debate. For instance warming DOES cause CO2 to rise as oceans warm. Gas solubility, specifically CO2, in water is an inverse function of temperature – so warmer water means less gas in solution, and if it isn’t in aqueous solution it is in the atmosphere. That is as much of laboratory fact as the fact that CO2 absorbs LWIR. Both statements are true. The real question is how important each one is in the climatic scheme of things and what aspects of the system moderate what would otherwise be a positive feedback loop.
Also, while I would agree that arguing that is no average global temperature is foolish, since any numerical data can be averaged, still an average is a mathematical artifact that one hopes will relate meaningfully to reality. Presently what we know about temperatures on a global scale is very limited and biased both in time and in spatial distribution. So, perhaps at present there is simply no useful estimate of global temperature at any high degree of precision. There certainly can’t be prior to satellite data acquisition.
@ur momisugly Dodgy.. “I want to start a “500 PPM” club, dedicated to the improvement of all growing plants…”
nah. just to annoy Weepy McGibben.. Towards 700ppm !! 🙂
The only significant anthropogenic atmospheric effect happened on the Moon. Apollo doubled the mass of the lunar atmosphere. Six times.
Dodgy Geezer says:
May 1, 2014 at 1:04 pm
…
I have lost count of the number of times someone has said to me: “Even if there’s no Global Warming, cutting CO2 output must surely be good?” ”
Anymore I just respond to the CO2 syncophants with “100,000 lemmings can’t be wrong”…
All those folks can do is follow, not think. 500 PPM Club…sounds like a great mug/t-shirt/cartoon….
Paging Josh….
Karim D. Ghantous says:
May 1, 2014 at 7:28 am
Here’s something I’d like answered: is there such a thing as a ‘global’ climate? Isn’t climate regional by definition? Mind you, Earth is a region in the solar system. But still, this question bugs me.
I think yes, there is something like global climate. It’s called ice ages. The global climate seems to have to stable states, either it’s an ice age or an intermediary. The small temperature fluctuations during an intermediary are just ‘weather’, imho.
In agreement with Paul Westhaver at 11:05 am on #9.
9. THERE IS NO SUCH THING AS A GLOBAL AVERAGE TEMPERATURE
I agree that one can try to arrive at a number but it is a meaningless figure and can’t be compared to anything in the past with any precision that bear relevance to the small changes in modern measurements, especially considering the suggested PRECISION of the IPCC…. So I disagree with you.
I think I would restate the argument as: There is no such thing as a global average temperature that HAS BEEN DERIVED FROM TEMPERATURES CONSISTENTLY RECORDED OVER DECADES. There are individual Global Average Temperatures that are only in general agreement, with bands of uncertainty larger than any signal that is attempted to be detected.
We could derive an average elevation of the earth. We could even derive an average elevation of the earth with 80% of the measurements from mountain tops. Year by year we could repeat the exercise again with 80% of the measurements coming from mountain tops, but different mountain tops. Fiinally, decades after the measurements are made, other researchers apply correction factors to account for erosion. We indeed would have an average elevation of the earth record, but it is biased by sample selection, contaminated by inconsistency and poorly justified historical adjustments. It would be A Global Average Elevation of the earth, but no one could believe it was THE average elevation of the earth.
Now, exchange temperatures for elevations, cities and micrositing issues for mountain tops and you have the ground thermometer A Global Average Temperature of the earth. But we do not have THE Global Average Temperature of the Earth.
Joseph Bastardi says:
May 1, 2014 at 12:55 pm
A ball park method of quantifying the effect of more CO2 on global average temperature:
1) Ignore all GHGs (or blanket molecules) except for CO2 & H2O, since the others occur in such low concentrations (ie, parts per billion or trillion).
2) Ignore differences in strength of GHG effect between the two gases.
3) Assume little or no increase in H2O concentration from increase in CO2 (at least as justified an estimate as IPCC’s unwarranted assumption of powerful positive feedback effect).
4) Then, using 30,000 parts per million as the average global level of H20 in the air, the increased GHG effect of CO2 gain from ~285 ppm in 1850 to ~400 ppm should be (30,400 / 30,285) = 1.0038, for 0.38% more heating.
5) Given an estimated total heating by the GHE of ~33 degrees C, we can therefore, in this very rough calculation, thank increased CO2 during the past 164 years for ~0.125 degree C of warming. This of course is liable to be a large overestimate, since the GHE is a logarithmic function, with most of the effect occurring at much lower concentrations of GHGs in the atmosphere.
http://ase.tufts.edu/cosmos/view_chapter.asp?id=21&page=1
Please feel free to adjust for the factors which I ignored, if you think adjustments are warranted or supported by theory or better yet observational or experimental data.