Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
Keep me logged in
New? Register here
Forgot your password?

Latest Posts

Archives

Roy Spencer’s Great Blunder, Part 2

Posted on 1 March 2011 by bbickmore

The following is reposted from Barry Bickmore's blog - it's PART 2 of my extended critique of Roy Spencer’s The Great Global Warming Blunder:  How Mother Nature Fooled the World’s Top Climate Scientists(New York:  Encounter Books, 2010).  If you haven’t read Part 1, you should probably do so before reading this.  See also Part 3.

Summary of Part 2:  Roy Spencer repeatedly claims that most of the rest of the climate science community deliberately ignores natural sources of climate variation, but then contradicts himself by launching an inept attack on the standard explanation for climate change during the glacial-interglacial cycles of the last million years (i.e., they are initiated by Milankovitch cycles).  The problems Spencer identifies are either red herrings or have been resolved, however, and he proposes no other explanation to take the place of the standard one.  In fact, climate scientists have used paleoclimate data such as that for the ice ages to show that climate sensitivity is likely to be close to the range the IPCC favors.  Therefore, it appears Roy Spencer is the one who wants to sweep established sources of natural climate variation under the rug.

The Mantra

It wasn’t easy slogging through Roy Spencer’s latest book, The Great Global Warming Blunder, because although it’s only 176 pages, it’s incredibly repetitive.  There is page after page of carping about how dense and corrupt his colleagues and the IPCC are, how hypocritical Al Gore is, and so on.  Most of this is just mildly annoying, but in my opinion, the language he uses in some of the messages he repeats ad nauseum is patently dishonest.  One such mantra is the claim that the climate science community has donned ideological blinders that prevent them from investigating natural sources of climate change.  Here are a few examples.

Aside from their almost total neglect of the role of nature in climate change, the scientists supporting the IPCC effort have done a pretty good job of summarizing the science of global warming, along with many of the uncertainties.  (p. xv)

We will see that researchers have reasoned themselves in a circle by first assuming that natural climate change does not exist, and then building climate models suggesting that only human pollution is needed to explain global warming.  (p. xxiii)

At this point you might be thinking, “Well of course natural climate change happens.”  But this has been surprisingly difficult to prove scientifically.  The IPCC avoids the subject because it detracts from the claim that humans are now the main driver of climate.  (p. xxvi)

The United Nations’ Intergovernmental Panel on Climate Change does acknowledge that there is natural climate variability on a year-to-year basis, and maybe even decade-to-decade.  After all, we have clear evidence that events like El Niño and La Niña cause some years to be warmer than others.  Yet the IPCC refuses to accept that the global warming (or cooling) on time scales of thirty years or more can also be caused by Mother Nature.  That, apparently, is humanity’s job.  (p. 1)

The IPCC has taken for granted that there are no natural variations in global average temperatures once one gets beyond a time scale of ten years or so.  (p. 16)

If Dr. Hansen is correct and humans are responsible for the recent warming, then what caused earlier periods of dramatic warming–and cooling?  Has natural climate change now ended, having been replaced by human-caused climate change?  This seems unlikely.  (p. 28)

Oh, there are many more–I just got bored of looking for them after about p. 30.  No matter how many times Roy Spencer says it, however, it is flatly untrue–and he knows it.  The fact is the he is the one that wants to ignore the evidence for past climate change, not the scientists associated with the IPCC.

Roy Spencer, Meet Sigmund Freud

How do I know Roy Spencer is aware of the truth-deficient nature of the above statements?  Because he says so in his book.  Check out his discussion of the standard explanation of what caused the glacial-interglacial cycles (i.e., intermittent ice ages) of the last million years or so, which involved huge swings in the global average temperature of about 4-7 °C.

The argument goes something like this:  There are long-term cycles, called Milankovitch cycles, in the Earth’s tilt and orbit around the sun.  These cycles cause small fluctuations in how much sunlight reaches different parts of the Earth.  The prevailing opinion is that the resulting variations in sunlight are not strong enough to have caused the ice age cycles shown in Fig. 6 unless there are positive feedbacks amplifying that small amount of forcing.  That is, unless the climate system is very sensitive.  When the Milankovitch cycles cause a small amount of warming, it leads to an increase in the CO2 content of the atmosphere.  But since more CO2 also causes warming, this sets up a vicious cycle of Warming, then more CO2, then more warming.  The process supposedly reverses when the Milankovitch cycles switch to causing a small decrease in the sunlight reaching the Earth.  A vicious cycle then occurs in the opposite direction, with decreasing CO2 and falling temperatures plunging the Earth into an ice age. (pp. 29-30)

So the other climate scientists do acknowledge the existence of large changes in the Earth’s past climate?  Changes so large that they can be described by phrases such as “vicious cycle” and “plunging the Earth into an ice age”?  And now Roy is telling us that not only do the other scientists acknowledge the existence of these changes, but they think they can actually explain them?

But wait!  Most of Roy’s statements I collected above apply specifically to the IPCC.  E.g., “The IPCC has taken for granted that there are no natural variations in global average temperatures once one gets beyond a time scale of ten years or so” (p. 16).  Could it be that climate scientists in general don’t ignore past climate changes, but the IPCC does?  All one has to do to pop that bubble of hope is to check out Chapter 6 of the Working Group 1 volume of the most recent IPCC report, which is entitled “Paleoclimate”.  It even includes a FAQ called, “Is the Current Climate Change Unusual Compared to Earlier Changes in Earth’s History?”  Their answer?  In some ways, yes, in other ways, no.  The chapter also includes another FAQ called, “What Caused the Ice Ages and Other Important Climate Changes Before the Industrial Era?”  The answer for the ice ages is… Milankovitch cycles.

I obviously can’t know what Roy’s motivations are, but this looks suspiciously like a textbook case of Freudian projection, because the fact is that information regarding large climate changes in the past is regarded by most climate scientists as an essential check on their projections of future climate, whereas it is extremely inconvenient for Roy Spencer’s ideas.  In the next section, for instance, I’ll show how he botches his discussion of the glacial-interglacial cycles so he can sweep them under the rug.

 Roy Spencer’s War on Data

Spencer’s central idea is that the Earth’s climate is fairly insensitive to external forcing.  But an “insensitive” climate means that changes in the incoming solar radiation, greenhouse gases, and so on, aren’t going to have a big effect.  If so, how can he explain the large climate changes that have happened in the past?  He doesn’t have a clue.  No, really.

But I don’t believe we have a clue what the governing factors were for these events.  As it is, our best Earth-observing satellites covering the globe every day are providing information that leads various scientists to different conclusions.  How can we hope to know what, if anything, the conditions on Earth in the distant past have to do with how the climate system operates today?  (p. 31)

What about the standard explanation for the glacial-interglacial cycles he mentioned?  He lists two main objections.  First, he argues that since ice core records show that temperature generally started changing before CO2 concentrations by several hundred years, CO2 can’t be a major cause of warming.

But if the major forcing of temperature really is carbon dioxide,… then the observed time lag either should be reversed or should not be there at all.  Therefore, the fact that the temperature changes preceded the CO2 changes in the ice core record is, to me, sufficient evidence that CO2 was not the forcing of, but instead the response to, the temperature changes.  (p. 30)

According to Spencer’s account of the standard explanation (see above,) the changes in CO2 during the glacial-interglacial cycles are regarded as a feedback, rather than the primary forcing, so it’s difficult to fathom with whom he thinks he’s arguing.  More CO2 can be dissolved in cold water than warm water, and there are a number of carbon sequestering and releasing processes involving ocean life.  Since it takes several hundred years for the deep ocean water to cycle up to the top, where it can be warmed up and lose CO2, it makes sense to suppose that if a warming event is initiated by something else (like changes in the amount and spatial distribution of incoming solar radiation,) the concomitant rise in atmospheric CO2 (which would enhance the initial warming) might lag behind by several hundred years.  There may also be other long-term feedbacks in the carbon cycle.  And while we can’t know for sure the reason for the lag time, it’s not as if it’s some great mystery for which nobody has come up with any plausible explanations.  There are actually a number of plausible explanations that are simply hard to test.  You can read all about different ideas regarding what governed CO2 concentrations during the glacial-interglacial cycles in (you guessed it) Section 6.4 of the last IPCC report (WG 1).

Now let’s move on to Spencer’s second objection to the standard explanation for the glacial-interglacial cycles.

But the biggest objection to the theory that the Milankovitch cycles caused the ice ages is that there is no statistically significant connection between the two!  A careful analysis has shown that the timing of the Milankovitch cycles relative to the ice ages is no closer than what would be expected by chance.  (p. 30)

In support of this claim, Spencer cites a paper by Carl Wunsch, an oceanographer at MIT (Wunsch, 2004).  Wunsh examined temperature records from several individual ice cores, and did a statistical analysis to show that very little of the temperature variation recorded could be explained by Milankovitch cycles.  This isn’t terribly surprising, since we’re talking about local records, which are much more prone to large, random fluctuations than the global average, but Wunsch’s point was important, because a number of previous studies had pointed to these local records as evidence of Milankovitch forcing.  In fact, they weren’t very good evidence for that.

When Roy Spencer saw Wunsch’s paper, he apparently glommed onto it as the last word on Milankovitch forcing–i.e., that we have no clue what caused the glacial-interglacial cycles, and we never will (even though Wunsch didn’t go that far).  But other scientists took the interesting questions Wunsch brought up and tried to address them.  Gerard Roe (U. Washington) showed that the rate of change of global ice volume correlates beautifully with the changes in incoming solar radiation due to Milankovitch cycles (Roe, 2006).  Peter Huybers and George Denton went on to show that the glacial-interglacial climate near the North Pole varies with the intensity of incoming solar radiation at those latitudes, while variations in Antarctic climate seem to be governed by changes in the duration of summer (Huybers and Denton, 2008).  So it appears that the Milankovitch theory is in better shape than ever.

Here’s the basic idea, once again, but explained a little more precisely.  1) Milankovitch cycles in the Earth’s orbit and tilt with respect to the Sun produce small variations in the amount and spatial distribution of sunlight hitting the Earth.  2) When these are on the increase in areas covered by ice sheets, small temperature changes are initiated that, in turn, start the ice sheets melting.  3) Since ice is very reflective, their melting causes a decrease in the albedo (i.e., the fraction of sunlight reflected back into space) of the Earth, which enhances the initial temperature change.  4) The oceans gradually release CO2 due to the warming, which further enhances the trend.  5) All of this reverses when the Milankovitch forcing starts pushing the system back the other way.

The great thing is that, since we can make good estimates of the changes in solar radiation, changes in the Earth’s albedo due to melting ice, and changes in atmospheric CO2 concentration during the ice ages, scientists can directly calculate the sensitivity of the climate to changes in the atmospheric CO2 concentration.  Obviously, there are uncertainties involved, but the result is that if you double the CO2 concentration, it’s likely to raise the temperature about 3 °C, plus or minus a degree or two.  Using models that reproduce more recent temperature data, the IPCC concluded that climate sensitivity is likely between 2 and 4.5 °C, with a best estimate of about 3 °C, and very unlikely less than 1.5 °C.  Scientists have come up with a number of other ways to estimate climate sensitivity, as well, sometimes involving paleoclimate data over widely divergent timescales, from hundreds of years to hundreds of millions.  And guess what?  They keep coming up with about the same answers.

This really is the crux of the whole matter.  If we’re going to go along with Roy Spencer, we have to reject a basic model of climate change that explains the data over widely divergent timescales, and replace it with… a big, fat nothing.  It’s not an argument about whether “Mother Nature” or mankind controls the climate, but over how the climate responds to changes in things like solar radiation and greenhouse gases, no matter what is governing them during a particular time period.  Spencer’s inept attack on the field of paleoclimatology is just his way of trying to sweep inconvenient data under the rug, all the while projecting his own rejection of established natural drivers of climate change onto the rest of the climate science community.

A Developing Theme?

If you read Part 1, do you notice a developing theme?  Roy Spencer finds a result he likes, and then stops looking.  In the next installment, I’ll reveal the worst example of all.

References

Huybers, P., and Denton, G. (2008) Antarctic temperatures at orbital timescales controlled by local summer durationNature Geoscience, 1, 787-792.

Roe, G. (2006) In defense of MilankovitchGeophysical Research Letters, 33, L24703.

Wunsch, C. (2004) Quantitative estimate of the Milankovitch-forced contribution to observed Quaternary climate changeQuaternary Science Reviews, 23, 1001-1012.

0 0

Bookmark and Share Printable Version  |  Link to this page | Repost this Article Repost This

Comments

Comments 1 to 39:

  1. Excellent,
    well written and most informative, looking forward to #3

    Thank you
    0 0
  2. If CO2 levels are a lagged response to temperature changes, then 800 years ago the Earth should have been burnt and drowned. The documentary could be called "The Snorkel Camels of Murmansk", starring Dr. Roy Spencer.

    "The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland,"" ...

    http://www.sciencedaily.com/releases/2009/10/091008152242.htm

    Even the most thick-skinned medieval chroniclers would have noticed that warm n wet trend at the door ... the window ... the roof.
    0 0
  3. Thanks for your great work in wading through this stuff and collecting all the relevent responses and links. That's a big job done.

    Without wanting to detract from what you've done, I would like to suggest that what SKS needs is long term is an article based on your work, but slightly different in tone. The good stuff on SKS is written in a detached tone - what wikipedia calls NPOV. Your essay at the moment is still slightly polemical in tone.

    Why is this important? Because with the good articles on SKS I can give them directly to a contrarian and they have to confront the ideas, because the language is neutral. If the language isn't neutral, then they reject the content before they get to it.

    The underlying problem is the form of communication. Polemical language is a form of in-group communication. It strengthens ties within an ingroup, by making those already in the group feel good about being in the group, and increases respect for the speaker for being right-thinking. But at the same time, it fails in communicating to anyone not in the in-group, because the tone immediately tells that person that the speaker is not right-thinking.

    So, for example, a hostile reader would immediately set 'How do I know Roy Spencer is aware of the truth-deficient nature...' against 'I obviously can’t know what Roy’s motivations are...' and turn your own words against you.

    Which begins to suggest to me that what we need is a wiki for turning good source material like yours into polished NPOV articles to live in the argument section long term. Because it takes multiple readers to pick up on things like this.
    0 0
  4. It is important to also note in the paragraph about sensitivity that the current value of between 2 and 4.5 °C / CO2 doubling is the short-term sensitivity - while the long term sensitivity is most likely around 6 °C / CO2 doubling !
    0 0
  5. Spencer is the main science advisor for the Cornwall Alliance. They released a paper called "A Renewed Call to Truth, Prudence, and Protection of the Poor: An Evangelical Examination of the Theology, Science, and Economics of Global Warming". Spencer authored the second part concerning the scientific case against AGW; while he mentioned paleoclimate in regard to the MWP and the LIA, he never mentioned the Ice Ages. However, the first section of the piece deals with the theological objections to AGW, and they *did* mention what caused the ice age:

    "While there is evidence that sea level was once much higher than it now is, that evidence is best interpreted in light of the flood of Noah’s day—a never-to-be-repeated, cataclysmic judgment of God that would have been followed by a sudden ice age (accompanied by much reduced sea level as water was stored in vast ice sheets on land) as the atmosphere lost its high water vapor content and so cooled rapidly, and then a gradual recovery as temperatures rose and water vapor rose to approximately its concentration(accompanied by a gradual sea level rise to present levels as the continental glaciers melted and ocean waters expanded as they warmed)." (page 15)
    http://www.cornwallalliance.org/docs/a-renewed-call-to-truth-prudence-and-protection-of-the-poor.pdf

    There you have it: The Ice Age was caused by Noah's Flood!
    You can't tell me he didn't know what was written in section one. He either had no problem with that claim or he lacked the integrity to withdraw from the document and the Cornwall Alliance. Considering his rejection of evolution, I have no trouble believing the former.
    0 0
  6. Roy Spencer has published essays stating that he thinks Creation explains the origin of life better than evolution see this Wiki article. He might agree with the Flood explaination.

    We need to remember that Spencer made the same accusations that everyone else was wrong and he was right with the satelite temperature data. For 10 years he insisted that his analysis showing the troposphere was not warming was correct and everyone else was wrong. In the end other scientists corrected Spencers mistakes and now the satelite record agrees with other methods. He was wrong before, why should he be correct this time around? The deniers do not care that he is always wrong, their only goal is to delay action until the problem is catastrophic.
    0 0
    Moderator Response: [Dikran Marsupial] Dr Spencer's religious views have no bearing on the correctness of his scientific arguments, and are getting very close to being an ad-hominem. Please confine the discussion to the science and steer clear of such issues.
  7. I second #3, Kevin C.
    I think it is great to have those outspoken rebuttals, and while polemical, I don't think it is over the top at all.

    BUT: We need the "official" version too, from which it could be cut and pasted almost anywhere, including encyclopedies. You may think of it as being a referee for a book chapter, pointing out the problems and inconsistencies without drawing conclusions. And re Spencer's relation to mainstream science, it is enough to describe it, and make a list of problems he does not acknowledge or relate to. Leave to the readers to draw their own conclusions. Less is more.

    And while it may be significant for an overall assessment of Spencer's character, his religous beliefs etc must be kept as separate as possible from his scientific involvement - even if he does not always keep the separation clearly enough himself. Which, to me, implies that comments about his beliefs and extra-scientific enterprises belon in the comments - not in the article text. However illuminating such information may be!
    0 0
  8. I think your post was excellent. I know it is hard not to say that a man IS a fool when he BEHAVES like a fool, but I think you did a pretty good job staying on the right side of the line.

    I have a question that is off-topic, and I hope you will feel free to relocate it elsewhere as you please. My question is about the mechanism of radiative heat transfer in the region of the strong CO2 absorption band. In this band absorption is so strong that the sky is essentially black. All outgoing radiation in the band is initially absorbed close to the surface of the earth. According to the Schwarzschild equation, the absorbed radiation is re-radiated upward and downward, so there is a balance of energy fluxes; it is not until, near the "top" of the atmosphere, that the radiation escapes entirely. Thus, the net flux in this band depends almost entirely on the temperature at the earth's surface and the temperature at this "top", both to the fourth power, of course.

    My question is simple: At what height (and temperature) is this "top" where the radiation flux is overwhelmingly upward? Is it above or below 10,000 meters? The reason I ask is that the lapse rate changes sign in the 10,000-15,000 meter region; rather than cool with increasing altitude, the atmosphere begins to warm (because of heat/radiation originating in the absorption of the sun's ultraviolet).

    The usual explanation for the CO2-caused greenhouse effect is that increased CO2 concentrations push this "top" region to higher altitudes where it is colder, and the reduction in radiative flux caused by colder temperatures causes warming at the surface. I understand this, I think. But what if this "top" is at or above 10,000 meters? That's the part I really do not understand, and I would appreciate any help in clarifying this picture. Thanks in advance!
    0 0
  9. Hi Kevin C #3,

    I honestly tried very hard to keep the tone moderate. In any case, I certainly didn't say everything that popped into my head! In the example you bring up, note that I didn't ascribe any particular motivation for why Roy Spencer said things about his colleagues that he knows are false. For all I know, he's just never thought about it hard enough to attain some sort of logical consistency.
    0 0
  10. Peter #8,

    I'm not the guy to answer that question, unfortunately. You'd have to find someone who is way into radiative transfer calculations.
    0 0
  11. What Kevin C says @3 is extremely important. I point to SkepticalScience often and the credibility of the site and its scientific response to the issues is crucial to being useful as a weapon against deception and misconception. I'd go so far as to suggest some of the recent articles on Spencer and Monckton should be reviewed in the light of maintaining a non-political, purely science based approach at SS.

    I am profoundly grateful for the job John has done in adhering to this approach and I'd hate to see it derailed by a few I'll advised comments in an otherwise very well reasoned post.

    I think that it will still be very obvious to objective readers as to the motivations and intentions of those being critiqued and, at the end of the day, all scientists make mistakes and deserve the benefit of the doubt. Despite some evidence to the contrary, most people can discern a trend when subtly pointed out!
    0 0
  12. > At what height (and temperature) is this "top"

    There's no "top" in that sense -- most of the total heat radiates away from lower down. You can find infrared photographs from satellites and see that. The air is so thin near the "top" that relatively very few molecules exist to radiate -- and those radiate in all directions of course.

    Here's someone working on building an explanation starting from a simple model and working up to a multiple-layer model and explaining why that's useful:

    http://how-it-looks.blogspot.com/2010/05/multi-layer-model-of-carbon-dioxide.html
    0 0
  13. Peter - Excellent question. Science of Doom has a page on that very topic here: Height of emission of OLR and DLR.

    Outgoing LW radiation occurs at an average of 5km near the tropics and 4km near the poles, as judged by spectra and the Stefan-Boltzmann law. This is well below the altitude of temperature reversal in the lapse rate.
    0 0
  14. @hank(12) Thanks. I'll have a look at your reference when I have some time.
    @KR (13) I know the mean height for outgoing LW radiation is 4-5 km (that's where the H2O concentration gets very low, due to cooling), but I'm interested in the height for the CO2 band, since CO2 concentration relative to O2 and N2 doesn't change with altitude. I'll keep trying. Thanks.
    0 0
  15. Re:#6.michael sweet

    Thanks you for the link to the wiki article showing how deep the anti-scientific beliefs of Roy Spencer reach.

    Roy Spencer accuse climate scientists of a "Great Blunder" in which he blames recent warming on ocean cycles like PDO and ENSO instead of greenhouses gases.

    He is dead wrong because in the past, the ENSO-PDO climate connection brokes down: during the so-called Medieval Warm Period, the Tropical Pacific was in a protracted COOL state, dominated by a NEGATIVE PDO:

    Variations in the Pacific Decadal Oscillation over the past millennium

    And a LA NIÑA protracted dominance:

    Fossil coral snapshots of ENSO and tropical Pacific climate over the late Holocene

    Proving that radiative forcing (in the case of the MWP, solar + volcanic) is by far the main driver of climate, not internal oceanic oscillations like ENSO and PDO like people like Roy Spencer want us to believe.

    Saying all this, I can also show that Roy Spencer, not having enough with spreading nonsense about the climate science, it is an advocate of a pseudoscience far worse than climate "skepticism": intelligent design, that is just a Trojan Horse for Creationism (or as can be described better, evolution denialism).

    The wiki page given by michael sweet links to this "gem" written by Roy Spencer in the right-wing magazine TCS daily:

    Faith-Based Evolution
    The nonsense seen here can be quoted:

    "Twenty years ago, as a PhD scientist, I intensely studied the evolution versus intelligent design controversy for about two years. And finally, despite my previous acceptance of evolutionary theory as "fact," I came to the realization that intelligent design, as a theory of origins, is no more religious, and no less scientific, than evolutionism."

    "While similarities between different but "related" species have been attributed by evolutionism to common ancestry, intelligent design explains the similarities based upon common design. An Audi and a Ford each have four wheels, a transmission, an engine, a gas tank, fuel injection systems ... but no one would claim that they both naturally evolved from a common ancestor."

    Can we trust a "scientist" that wrote such a piece of disinformation?

    This is not a matter of religious beliefs. The problem here is that he believes that "intelligent design" is a valid scientific theory and should be teached alongside mainstream evolution.

    This is just crazy. Strange that many climate "skeptics" are also evolution "skeptics". I suspect an ideological, right-wing common root on both positions.
    0 0
    Moderator Response: [DB] Fixed link.
  16. Peter Offenhartz - From Daniel J. Jacob, Harvard, working from CO2 emission lines rather than H2O: The 15 mm blackbody temperature in Figure 7-8 is about 215 K, which we recognize as a typical tropopause temperature. It looks like the CO2 effective emission altitude is around 10km or so.
    0 0
  17. @KR (16) MANY THANKS for pointing me toward the Daniel J. Jacob reference at Harvard. His article is at once brief, comprehensive, and clear. As you note, the main CO2 effective emission temperature is about 215K, which is, I'll bet, right at the knee in the lapse rate curve, which means that rising CO2 concentrations will have little climate effect IN THE MAIN ABSORPTION PEAK. Lest anyone think I've become a global warming skeptic, the real action from changing CO2 concentrations must be taking place on the absorption wings, where the effective temperature is much higher and where rising CO2 concentrations should indeed cause a falling emission temperature. This picture clarifies my understanding considerably, but I'll have to spend more time studying Jacob's chapter. Thanks again KR.
    0 0
  18. Peter Offenhartz @17, you may well be interested in the post on Theory and Experimant at Science of Doom. It contains (amongst other gems) this illustration of the effect of doubling CO2 on radiative forcing:



    As you can see, most of the effect is in the wings of the 15 micron trough, although there is a slight deepening of the trough in the center, which is the second largest effect. Some other absorption bands currently barely detectable in atmospheric spectrums also start to strengthen.

    This is the non-equilibrium response. As the Earth warms to restore equilibrium, there will be an increase in radiation at all frequencies, so that in the equilbrium case, there would be more radiation from the center of the 15 micron band, not less.

    Although KR has found mention of 215 K as the brightness temperature at the center of the 15 micron band, I have noticed it as being centered around 220 K, with tropical spectra above that, and polar spectra below.
    0 0
  19. Peter, regarding the very center of CO2 absorption, you should take a close look at a graph of the measured outgoing spectrum from Earth, for example this one posted at ScienceOfDoom here - http://scienceofdoom.com/2010/05/12/co2-an-insignificant-trace-gas-part-eight-saturation/



    You'll notice that right at the center of the 15 micron dip there's a narrow spike. That higher level of emission right in the center of the absorption band is from the warmer temperatures in the stratosphere, just as you guessed. But the dependence is not the T^4 rule, that applies only to the overall integral of emission over all wavelengths. The specific law for a single wavelength is the Planck function, which is roughly linear in temperature for high temperatures, but drops very quickly to zero at low temperatures.
    0 0
  20. apsmith @19, I'm curious as to why you bring up the Planck function. I don't doubt what you say, but it does not mean you cannot judge temperatures of gases from the relative intensity of their emission spectra at a give wavelength relative to the intensity predicted by a black body curve.

    Thus, in your illustration, and ignoring complexities related to emissivity, we can see the surface temperature was less than 275 K, and hence close to freezing. We can also see that the average temperature of CO2 molecules emitting to space was around 223 K at that location. That is what Peter was doing, and quite correctly.

    In fact, physicists often do the same thing more formally by plotting the spectrum as brightness temperature against wavelength instead of radiance against wavelength. One example (from here) is this plot, clearly from a tropical sounding:

    0 0
  21. bbickmore,

    I think you're being a little disengenuous or atleast knit-picking here. I think you know that he thinks that multi-decadal to centennial natural variation are ignored by the IPCC. Technically your right in what you're saying, and sure you've highlighted some sloppiness in some out-of-context sentances but why use the example of millions of years cycles to criticism like this "...on time scales of thirty years or more...". I think to provide a substantive critique of Spencer you should be showing the solidity of the understanding of multi-decadal change. So far you have managed to skillfully avoid it.

    In some respects this is part of the problem with the plethora of recent 'skeptic bashing' articles on this website. It's more concerned with point scoring and discrediting the individuals than it is about understanding their concerns.
    0 0
  22. Tom (@20) - I don't think we're disagreeing, I recently blogged on the subject of the temperature associated with emission to space. My only point was the Planck function for a given wavelength is not proportional to T^4, only the integral over all wavelengths is.
    0 0
  23. Moderator,
    I agree with from Peru that Roy Spencers anti scientific ideas about Evolution and Creation cast doubt on his scientific judgement. I do not like the suggestion of ad-hominem at #6. Can you suggest what is appropriate on this site in this situation so that I know for future reference? Thank you for your help.
    0 0
    Moderator Response: [Dikran Marsipial] The Comments policy explicitly forbids ad-hominem attacks, which are an attack on the source, rather than the content of an argument. Dr Spencers views on evolution have no bearing on whether his theories on climate are correct or not, and they should stand or fall on their own merits. Several contributors to Skeptical Science are committed Christians (and other faiths), including myself, there are plenty who would say that such views are unscientific (I would agree) and/or delusional (I don't agree there ;o). Does that mean skeptics can dismiss any of my arguments on the basis that I have religious beliefs? It is a slippery slope, and it is part of the distinctive nature of Skeptical Science that the discussion is centered on the science and logical fallacies such as the ad-hominem are discouraged, it is one of the features that makes Skeptical Science (in my view) the best of the climate discussion forums. Note that Spencer has frequently refuted other skeptic arguments, such as that CO2 is not a greenhouse gas, that the greenhouse effect contradicts the second law of thermodynamics, or demonstrating that the results of Lindzen and CHoi were substantially flawed. Are those arguments devalued by doubt on his scientific judgement? No, their value is determined by their internal consistency and support from the data and experiments.
  24. HR - I would be more inclined to agree with your criticism if Spencer didn't try to poke holes in the Milankovitch cycle theory. Given that he did, I think it is fair to critique his argument against Milankovitch cycles.

    I think the idea that there is a 60 year, 1,000 year, etc cycle has some problems, one of which is we are 40 years into a 60 year "cycle" - the sun is about to end its quiescence and while it is theoretically possible, it is highly doubtful that the next 20 years will show any cooling. So that blows up the 60 year cycle. The data for longer term, non-Milankovitch cycles is even weaker.

    I think Spencer is essentially looking for a miracle in the 5% probability that the IPCC leaves on their predictions.

    So in the sense that anything is possible - sure. In the sense that we have a pretty good understanding of the climate system, and at this point studies are confirming model-predicted behavior, not so much.
    ____________
    Kevin C @ # 3 - excellent comment. Very well said and I agree. I was squirming in my chair, realizing the analysis was pretty good, but the tone is not up to SKS standards.
    0 0
  25. apsmith @22, great blog post, and your fourth figure illustrates very well your claim about the Planck function.

    As indicated, I wasn't sure you were disagreeing with anything. I was just uncertain as to why you thought it important to mention the Planck Function in this context.
    0 0
  26. @apsmith (19) I'm afraid I have to agree with Tom Curtis (20). It is possible to assign a temperature to a specific wavelength/frequency. As for the central spike in the CO2 absorption, that simply reflects a different temperature/altitude for that particular wavelength region. One cannot assign a uniform temperature for a broad band, and the T^4 rule applies always. not just to the overall integral. But that's an awfully small point. The main point I was trying to make is that if the temperature/altitude point for the main-band CO2 upwards emission lies at an altitude that coincides with the knee of the lapse rate (as it apparently does), rising CO2 concentrations won't affect global warming. But the wings will.

    As for Tom Curtis (18), I will have to take a look at your references (I find the graphic you provided confusing), and I will try to find time to get back to you. But I doubt that increasing CO2 concentrations can affect the emission temperature at the center of the CO2 absorption band. But the wings (and maybe even that blip in the middle of the band) surely are important. Thanks for your help. I think I am learning!
    0 0
  27. HR:

    So far you have managed to skillfully avoid it.

    This seems uncomfortably close to an accusation of dishonesty.

    In some respects this is part of the problem with the plethora of recent 'skeptic bashing' articles on this website. It's more concerned with point scoring and discrediting the individuals than it is about understanding their concerns.

    That's an odd thing to say. Surely concerns should be based on hypotheses and data that can withstand critical scrutiny? And if they aren't, surely that says something about their validity?

    Some "skeptics," when confronted with errors they can't defend, resort to insinuating that their opponents are wrong in some obscure moral sense, despite being correct on the facts (e.g., they're "point scoring," which is somehow shabby and disreputable). I hope you're not trying to take that approach here.
    0 0
  28. Peter Offenhartz @26, the blue plot on the graph (CO2) is just the radiance spectrum for 287 ppm CO2 - that for 584 ppm. The area under the blue curve is then change in forcing for that change in CO2 concentration.

    If you compare wavelengths on that diagram with the wavelengths with the diagram linked by KR, you will see that 15 microns lines up with the center of the main trough produced by CO2 in the spectrum. The two large peaks at approximately 13.5 and 16.5 microns on the diagram I posted then line up with the "wings" of the CO2 trough.

    Here is that KR's linked image for easy comparison. You will notice the wave lengths are marked along the top of the diagram.

    0 0
  29. Responding to (3), (7), and (11)... I concur that the tone of SkepticalScience has been and continues to be exemplary -- all credit to John Cook who has created something truly valaubel here.

    However... I do think we need to concede something of a special case in the case of Roy Spencer and his book. Roy has -- on his blog, in numerous public talks (one of which I witnessed personally) and now in his book -- not only put forth scientific arguments, but also directly accused his colleagues of deliberate malfeasance ["I find it difficult to believe that I am the first researcher to figure out what I describe in this book. Either I am smarter than the rest of the world’s climate scientists–which seems unlikely–or there are other scientists who also have evidence that global warming could be mostly natural, but have been hiding it. That is a serious charge, I know, but it is a conclusion that is difficult for me to avoid." (p. xxvii)]

    I fully concur that our primary purpose here must be to improve understanding, and of course that involves taking a tone that does not immediately put off those who are resistant to the information. However, in addition to clear exposition of the science, I think it's also important to help folks understand that there are people like Roy out there exhibiting a level of obtuseness over decades. Roy's work, as I believe Dr. Bickmore and others have demonstrated, is simply not intellectually honest. If one needs to be a bit more direct in making that point, I think in this case it's warranted -- and indeed beneficial to effective communication. I think Dr. Bickmore has successfully walked a very fine line.
    0 0
  30. Im intrigued about this claim that natural causes havent been investigated. I have just waded through the summaries on sceptical.science.com of 20 odd papers on the affects of the sun, and read some of the originals, and I still have a headache from it all as my maths is rusty. Did I hallucinate all that? Isnts 20 papers enough? How many does Mr Spencer want? What planet does he live on?
    0 0
  31. As for the problem of the rising of the emission level above the tropopause (Peter Offenhartz #8), the height of the tropopause depends on temperature. An increased GHG absorption will move both the tropopause and the emission level upward.

    In equilibrium and at wavelengths where the atmosphere is optically thick, the emission level will roughly be that corresponding to the effective temperature of the planet of about 220 K. In reality, the absorption coefficient depends on the number concentration of CO2 (number of molecules per meter squared), not relative concentration (ppm), and hence on pressure and altitude. Detailed calculation are required.
    0 0
  32. @From Peru
    „I suspect an ideological, right-wing common root on both positions.”

    Such thinking is the road to nowhere. Professor Z. Jaworowski radiologist, and V. Klaus economics professor, in his books "proving" that has Hitler and Stalin were in favor of clean environment - their leftist views formed the basis for the theory of AGW. It's absurd conspiracy theories.

    Skeptics are split into much more than we imagine supporters of AGW. Eg I do not agree with R.S. that is ENSO - PDO (internal climate forcing) decide on changes in cloud cover - and those of the ENSO-PDO (feedback). I agree that determines the nature - the sun (not AGHG), but in a much more complicated - and not chaotic.

    After the publication of the IV report, many papers on AGW supporters - who say they generally agree with the theory of AGW - rebel against allegations that the IPCC models did not appreciate, for example: QBO, volcanic effects on ozone, the effect of ozone on a pair water in the stratosphere and vice versa, lunar cycles, the newly discovered solar cycles, cycles of changes in UV solar magnetic cycles of geo-solar, ENSO impacts on phytoplankton (and vice versa) ..., that the respiration of peat is twice the pandas than estimated in the IPCC report, that are not reflect changes in regional Q10 reduces the actual amount of respiration by 25%, etc.. ...

    Recently for example, Mike Lockwood said that a slight change in the UV (energy - compared to RF CO2) has a huge impact on the jet stream - causes that I am in Poland for 3 weeks I have from 1030 to 1040 hPa and "suffer" from the arctic cold ...

    Though it shows the “feet of clay” and can be based on the great theory of AGW.

    R. Spencer (also R. Pielke) is certainly right in one thing: we know too little about natural climate variability.

    Really about how many regions we can say: “... strong late 20th-century warming (during the warm season) in western North America may have a considerable component of natural climate variability in the signal.”? (Tree rings and past climate in the Arctic, Juday et al., 2010).

    P.S. And evolution has much in common with the climate - for millions of years in practice it was not - occurred only a short time of rapid climate change.
    0 0
  33. Arkadiusz Semczyszak #32,

    I have on occasions heard Professor Mike Lockwood being quoted as a supporter of the "solar theory" of climate change. This is a distortion of his position. While he believes that sun influences the jet stream and the Northern Hemisphere climate, he is in no doubt that the earth is warming due to CO2.

    You can read this paper:

    Solar change and climate: an update in the light of the current exceptional solar minimum

    Quote
    " In the case of climate change, there is no doubt that global mean temperatures have risen, so that the effect is known to be real. Furthermore, there is a viable explanation of that effect, given that the amplification of radiative forcing by trace GHG increases by a factor of about 2 is reproduced by global coupled ocean–atmosphere models. What is alarming is that in the face of this strong scientific evidence, some Internet sources with otherwise good reputations for accurate reporting can still give credence to ideas that are of no scientific merit. These are then readily relayed by other irresponsible parts of the media, and the public gain a fully incorrect impression of the status of the scientific debate. "
    0 0
  34. nigelj @30: I think the key to understanding his meaning is to look at his recent "challenge to the climate research community".
    Studies that have suggested that an increase in the total output of the sun cannot be blamed, do not count…the sun is an external driver. I’m talking about natural, internal variability.

    Indeed, his focus on "natural" variability excluding the sun keeps popping up in his writings, at least on the blog. More specifically I think he often means "natural variability" to refer to his causality-backwards idea that cloud cover drives mutli-decade climate trends.
    0 0
  35. @apsmith(19) Many thanks for the link to scienceofdoom.com. The article was clear and informative, and confirmed my own investigations(!).
    0 0
  36. WheelsOC @30,

    I think you're right that when Roy Spencer says "natural climate variablity" he really means "natural climate variability due to fluctuations in cloud cover". But that's not what he said, and some of the quotations above definitely imply that mainstream climatologists can't explain any climate change in the past before humans started burning lots of fossil fuels. So even if we try to give him a little leeway on his meaning, he still comes out looking disingenuous.
    0 0
  37. Barry: having read part 3 on your blog, I'd like to withdraw my comments on the tone. In the light of part 3, the tone of parts 1 and 2 makes a lot more sense to me.

    In retrospect, I now see the form you have adopted: It is a 'journey narrative'. Part 3 makes this obvious in that you document how you explore Spencer's ideas for yourself a step at a time and found them wanting.

    This is an extremely effective form of communication, especially to non-scientific and particularly post-modern audiences. As evidence, look at how many science documentaries are now personal narratives of how a scientist came to a particular understanding. It personalises the material and makes it easier to relate to.

    Evangelical Christians also often use this form - it is called 'sharing your testimony'. In addition to being an effective means of communication, it has another benefit that it is much harder to argue with personal experience than with evidence - not that that is a relevent concern in your case. If I were given the opportunity of explaining evolution to an audience of my fellow Christians, I would adopt the same form, describing my journey from a pure physics background into discovering molecular sequence data and what I could do with it.

    So actually, I think the form you have chosen perfectly fits your material. Maybe we should be looking for other elements of climate science we can communicate in this way - Tamino's anniversary rant about reproducing stuff for himself might provide some source material. It's a different mode of communication to that usually employed at SKS, but it is an effective one and one which had the potential to reach different audiences.
    0 0
    Moderator Response: [Dikran Marsupial] While Kevin has legitimately mentioned evolution in passing, while discussing methods for communicating science, this should not be regarded as an invitation to discuss evolution or intelligent design etc., which is clearly off-topic.
  38. Thanks Dikran for pointing that out. In fact, the entire paragraph added little to the point I was making and will distract from it for some readers - my point would be improved by deleting it if you feel inclined. Sorry for the inconvenience.

    If I may expand: There's a huge can of worms concerning communication which I think needs discussing, and I'm not sure where the discussion should take place. I've barely begun to scratch the surface. Can I illustrate by some questions:

    1. Who is SKS speaking to? How does that affect the form of communication SKS should adopt? (Has this question even been asked? Or did it happen the other way round: The form of communication - NPOV academic with lay summaries - was chosen and the resulting audience was a unplanned consequence.)

    2. Who is Barry speaking to? To Roy Spencer, to people who have read his book, or to people who might encounter people who have read his book? How does that affect the form of communication?

    3. Who are the contrarians and what are their motivations? How do we best communicate to different contrarian groups? Which groups are most accessible to persuasion? (As an illustration, communicating to someone who regards themselves as a rational skeptic who has made a reasoned rejection of a consensus view is very different to someone whose views are derived from a political ideology, or someone whose views are determined by the need to conform to a peer group. In the last case, changing someone's mind might destroy their social network - a hard challenge).

    There appears to be an active sociological and cultural anthropological academic literature on these issues. 5 mins with google pulled up these:
    http://www.stanford.edu/group/CCB/articles/Anderegg_ClimateConsensus_Report2009.pdf
    http://www.carleton.ca/isema/documents/editions/ISEMAFall2006.pdf#page=10
    http://pus.sagepub.com/content/16/2/223.short

    I don't even know where to start, and if I were to do so the sociologists would rightly be laughing at me and whispering 'Dunning Kruger' to one another.

    What I'd really find useful is some articles, possibly be sociologies/social anthropologist writing in lay terms, on understanding who the different groups are skeptics are and how they are being so successful in communicating a message. Also what forms of communication are open to us and how to chose between them.
    0 0
    Moderator Response: No problem, your mention was fine as it was only an illustrative aside.
  39. @Shoyemore

    As quoted by you (perfectly known to me), Mike Lockwood's paper, is also an important sentence: "... the current [solar] grand maximum has already lasted for an unusually long time ..."

    Lockwood (in this paper) will not close a road to prove that the Sun has a more significant impact on the climate than we thought previously. However, imposes a condition:
    “Thus advocates of the huge solar amplification (positive feedback) factor [that is, for example, I] must also explain why the feedback to greenhouse forcing is at the same time negative. The issue is not ‘can the GMAST curve be fitted with combinations of solar variations’—with enough free variables the answer will be ‘yes’ (but such fits would have very low or no statistical significance): the challenge for attempts to show such a phenomenon could be real is to give credible explanations of feedback amplifications of more than 13 within the constraints set by observations and their uncertainties (and yet still give negative feedbacks to GHG forcings).”

    As cited above, this paper presents but too little potential direct and indirect influences of the Sun, which completes Lockwood (as a co-author) in a later work: Solar Influences on Climate, L.J. Gray, J. Beer, M. Geller, J.D. Haigh, M. Lockwood, K. Matthes ,U. Cubasch, D. Fleitmann, G. Harrison, L. Hood, J. Luterbacher, G. A.
    Meehl, D. Shindell, B. van Geel, W. White (Reviews in Geophysics, 2010).

    In this work - with many "types" of direct and indirect sun (especially the impact of changes in solar UV - for example, ozone, ozone in the stratosphere, water vapor, etc..) is a record that they require “urgent” research - because we know about them too enough - to assess (even initially) the actual impact on climate.
    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

TEXTBOOK

THE ESCALATOR

(free to republish)

THE DEBUNKING HANDBOOK

BOOK NOW AVAILABLE

The Scientific Guide to
Global Warming Skepticism

Smartphone Apps

iPhone
Android
Nokia

© Copyright 2014 John Cook
Home | Links | Translations | About Us | Contact Us