Update To Andy Revkin’s Question In 2005: “Is Most Of The Observed Warming Over The Last 50 Years Likely To Have Been Due To The Increase In Greenhouse Gas Concentrations”?
By Dr. Roger Pielke Sr.
In 2005, I posted an answer to Andy Revkin’s question on climate change;
Response to Andy Revkin’s Science Question of August 26, 2005
“Is most of the observed warming over the last 50 years likely to have been due to the increase in greenhouse gas concentrations”?
My answer in 2005 started with the text
On Global Warming:
There are natural explanations for global warming of which a change in the output of solar energy is a candidate. However, none of the published work has convinced me that this can explain much of the observed global warming over the last several decades. Volcanic emissions are another natural global forcing, and it is well known that they produce cooling, such as after the eruption of Mount Pintatubo, where in August of 1991 it was estimated as -4 Watts per meter squared. There have not been eruptions of that magnitude since, such that the absence of such major eruptions might permit greater absorbed solar radiation in the climate system than otherwise would occur. However, this absence of eruptions resulting in any positive radiative imbalance for a period of time well after a major volcanic emission has also not been shown to occur. This leaves anthropogenic emissions as a source for global warming.
There is new information, however, that prompts me to update my answer.
This is based on insight provided by Roy Spencer, as summarized in his post of April 20 2010 titled
The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists
where he presented his new book with the same title published by Encounter Books.
The text in his April 20th post that provides this perspective of the natural climate system is
“The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.
How could the experts have missed such a simple explanation? Because they have convinced themselves that only a temperature change can cause a cloud cover change, and not the other way around. The issue is one of causation. They have not accounted for cloud changes causing temperature changes.”
Other colleagues whose studies, in combination, have convinced me of a larger natural variability with respect to global warming and cooling, include as examples, the following papers, blogs and presentations
Baldwin, Mark P. and Timothy J. Dunkerton, 2001: Stratospheric Harbingers of Anomalous Weather Regimes. Science 19 October 2001:Vol. 294. no. 5542, pp. 581 – 584 DOI: 10.1126/science.1063315
Posts by Joseph D’Aleo on http://www.icecap.us/ [see http://icecap.us/index.php/go/about-climate-change]
Compo, G. P., and P. D. Sardeshmukh, 2009: Oceanic influences on recent continental warming. Climate Dynamics, 32,333-342. [see my post on this paper in 2008]
R.S. Lindzen, M.-D. Chou, and A.Y. Hou (2001) Does the Earth have an adaptive infrared iris? Bull. Amer. Met. Soc. 82, 417-432
W. M. Gray, 2009: Climate change: Driven by the ocean – not humans. The Steamboat Institute Conference, Steamboat Springs, Colorado, August 29, 2009.
Stephens, Graeme at the August 2009 GEWEX meeting in Melbourne Australia in a talk titled “Earth observations and moist processes”.
Sun, D.-Z., Y. Yu, and T. Zhang, 2007: Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations. J. Climate [a powerpoint talk of this research was completed for my class in 2007 Human Impacts on Weather and Climate(see Validating and Understanding Feedbacks in Climate Models).
Thompson, D. W. J. and J. M. Wallace, 1998: The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophys. Res. Lett., 25, 1297-1300.
Trenberth, K. E., D. P. Stepaniak, and J. M. Caron 2002: Interannual variations in the atmospheric heat budget J. Geophys. Res., 107, D8, 10.1029/2000JD000297.
A.A. Tsonis, K.L. Swanson, and S. Kravtsov, 2007: A new dynamical mechanism for major climate shifts. Geophys. Res. Lett., 34, L13705, doi:10.1029/ 2007GL030288.
A.A. Tsonis and K.L. Swanson, 2006: What do networks have to do with climate? Bull. Amer. Meteor. Soc. doi:10.1175/BAMS-87-5-585.
Marcia Wyatt, Ocean Heat, April 27 & May 4, 2007 in my class on Human Impacts on Weather and Climate [natural climate variability is currently her Ph.d. dissertation topic working with A. Tsonis and S. Kravtsov].
I am also further convinced based on the recognition that there is “missing heat” in the climate system (e.g. see the recent set of posts on this topic starting with this one). The long term variations in atmospheric and ocean circulation features, with resulting global average changes in radiative forcing, can explain at least part of the reason for this “missing heat”.
In 2005 I wrote a post
What is the Importance to Climate of Heterogeneous Spatial Trends in Tropospheric Temperatures?.
Roy’s perspective, bolstered by such colleagues as listed above, provides convincing further evidence that such variations in regional heating and cooling can alter significantly the global average heating more than has been indicated by the IPCC-type multi-decadal global climate model simulations.
The solar influence also appears to be larger than was understood in 2005, as illiustrated by these papers
Scafetta N., R. C. Willson (2009), ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model, Geophys. Res. Lett., 36, L05701, doi:10.1029/2008GL036307.
Lean, J. L., and D. H. Rind (2009): How Will Earth’s Surface Temperature Change in Future Decades?,
Geophys. Res. Lett., doi:10.1029/2009GL038932, in press. (accepted 9 July 2009).
The 2010 answer to the question by Andy Revkin
“Is most of the observed warming over the last 50 years likely to have been due to the increase in greenhouse gas concentrations”?
remains NO.
The added greenhouse gases from human activity clearly have a role in increasing the heat content of the climate system from what it otherwise would be. However, there are other equally or even more important significant human climate forcings, as I summarized in my 2005 post and in the 2009 article
Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell, W. Rossow, J. Schaake, J. Smith, S. Sorooshian, and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union.
We now know, however, that the natural variations of atmospheric and ocean circulation features within the climate system produces global average heat changes that are substantially larger than what was known in 2005. The IPCC models have failed to adequately simulate this effect.
The answer to Andy’s question from 2005 is an even more clearly No. That is a signficant fraction of the observed warming over the last 50 years is NOT due to the increase in greenhouse gas concentrations”?
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“Perhaps you can explain just how that works, how do 8 molecules per million molecules manage to intercept every single part of UV below 240nm?”
Disclosure — I have no training in climate science
Intuitive answer to this question — Layers
onions have layers…atmospheres have layers. UV radiation goes through enough layers of molecules and it will eventually hit an ozone molecule.
reminder to read the disclosure…
James
Leif Svalgaard says:
May 6, 2010 at 10:49 am
Thank you for the information.
PJP says:
May 6, 2010 at 9:18 am
The Nils Bohr reference above (Enneagram post) I have seen before, but not really thought through the implications. I spent more time thinking about the rock salt/glass greenhouse experiment.
The implication is that once a CO2 molecule becomes excited enough to jump to its higher energy state, it will not absorb any more IR energy. This implies that as CO2 is exposed to higher and higher intensity of IR, more and more atoms will become excited, and the CO2 will become more and more transparent to IR
The Niels Bohr reference didn’t show a difference, simply because CO2 doesn’t absorb in the (small) band of IR that the sun emits! CO2 absorbes parts of IR of much longer wavelengths where the earth’s temperature emits. The spectra of incoming sunlight and outgoing IR from the earth have practically no overlap…
Anyway, in about the same time frame as Niels Bohr, others have done experiments with free flow CO2 over a flame and captured the emittance of the CO2 molecules on a thermocouple through a small hole: they measured the temperature increase from the extra radiation. I have to lookup the reference…
Don’t forget the time frame in the CO2 laser: the excitation lasts only a fraction of a second, before the electron falls down to its original state, emitting a photon, which is what drives your laser (even then, 90% of the energy supplied is heating up the laser which needs to be cooled)… In the free atmosphere at a density not too far from the surface, even during this fraction of a second, the possibility of a collission with neighbouring O2 or N2 molecules is huge, which means that a large part of the absorbed energy is transferred to the rest of the atmosphere as an increase in motion, thus temperature.
A C Osborn says:
May 6, 2010 at 11:15 am
Thank you for the information.
You are welcome. Did it sink in?
Ferdinand Engelbeen says:
May 6, 2010 at 8:57 am
Good response, I really dislike it when posters overstate the case against AGW. There’s plenty of evidence based on sound science to refute the scares.
There’s one thing I have been trying to find with little success. We know the increase in CO2 has led to an increase in biomass, both in oceans and on land. This increased biomass then necessarily utilizes energy which can no longer be used to heat the atmosphere. This is clearly a negative feedback. Is there anyway one could determine what percentage of the W/M2 attributed to CO2 increases is utilized by the added biomass?
PJP says:
May 6, 2010 at 9:18 am
The Nils Bohr reference above (Enneagram post) I have seen before, but not really thought through the implications. I spent more time thinking about the rock salt/glass greenhouse experiment.
However, thinking more about the explanation that CO2 absorbs IR radiation and moves to a more excited state leads to some interesting questions (in my mind, at least).
The explanation (energy levels) sounds believable. We know that CO2 does behave this way because we have CO2 lasers which depend upon this effect. Also, absorbed energy has to go somewhere, and this explains where.
The implication is that once a CO2 molecule becomes excited enough to jump to its higher energy state, it will not absorb any more IR energy. This implies that as CO2 is exposed to higher and higher intensity of IR, more and more atoms will become excited, and the CO2 will become more and more transparent to IR.
No completely wrong, if a ground state CO2 molecule absorbs a 667cm^-1 photon it’s promoted to the 010 state, there’s nothing to stop that molecule absorbing another 667cm^-1 photon and being promoted to the 020 state, and so on.
In our atmosphere this isn’t very likely because collisions with other molecules happen so rapidly that it gets deactivated to the ground state so fast. Of course once there it’s free to absorb again!
Leif Svalgaard says:
May 6, 2010 at 10:57 am
“The problem is that the Internet has dumbed down the ordinary Joe with its overload of pseudo-science and ignorant crap.”
Absolutely true. It is also true that it has enabled the CRU emails to gain wide circulation. It has enable hard working scientists who are not in universities to communicate a little easier and publish their work (whether peer reveiwed or not). I truly believe that if it wasn’t for the internet there would not be as many sceptics around today.
Leif Svalgaard says:
May 6, 2010 at 10:57 am
“The problem is that the Internet has dumbed down the ordinary Joe with its overload of pseudo-science and ignorant crap.”
One last thing the “pseudo-science and ignorant crap” has also been emanating from the AGW camp too.
Jimbo says:
May 6, 2010 at 1:15 pm
One last thing the “pseudo-science and ignorant crap” has also been emanating from the AGW camp too.
Yes, it is widespread.
Ferdinand Engelbeen says:
May 6, 2010 at 11:27 am
The Niels Bohr reference didn’t show a difference, simply because CO2 doesn’t absorb in the (small) band of IR that the sun emits! CO2 absorbes parts of IR of much longer wavelengths where the earth’s temperature emits. The spectra of incoming sunlight and outgoing IR from the earth have practically no overlap…
I don’t think you understood the experiment. In the experiment, Wood filtered out the incoming IR from the Sun. Thus, you have no IR coming into the two enclosures. But, the black lining should emit IR, and the IR trapping glass enclosure should therefore become hotter under the Greenhouse hypothesis. It did not, or at least, not significantly. As in the Sun/Earth system, there was no overlap between the incoming and outgoing IR. I’m not hanging my hat on this experimental outcome, just trying to clarify what is being discussed.
Leif Svalgaard says:
May 6, 2010 at 10:49 am
“Enough absorbers to do the trick.”
But, these are two very different systems. The ability to block incoming UV is not a function of the number of molecules, but of their spatial density, which has to be on the order of a wavelength. Back of the envelope calculations based on your numbers show the O3 is distributed densely enough to intercept UV. Is that also true for CO2? I take it for granted it is, but I’d like to see the calculation.
Leif Svalgaard says:
May 6, 2010 at 10:57 am
“The problem is that the Internet has dumbed down the ordinary Joe with its overload of pseudo-science and ignorant crap.”
_______________________________________________________________________
Lief it is not the Internet to blame but an educational system that produces “team players” with just enough education to be useful as factory drones… well maybe.
“For 10 years, William Schmidt, a statistics professor at Michigan State University, has looked at how U.S. students stack up against students in other countries in math and science. “In fourth-grade, we start out pretty well, near the top of the distribution among countries; by eighth-grade, we’re around average, and by 12th-grade, we’re at the bottom of the heap, outperforming only two countries, Cyprus and South Africa.” Source: http://www.enterstageright.com/archive/articles/0804/0804textbooks.htm
“… Surveys of corporations consistently find that businesses are focused outside the U.S. to recruit necessary talent. In a 2002 survey, 16 global corporations complained that American schools did not produce students with global skills. United States companies agreed. The survey found that 30 percent of large U.S. companies “believed they had failed to exploit fully their international business opportunities due to insufficient personnel with international skills.” One respondent to the survey even noted, “If I wanted to recruit people who are both technically skilled and culturally aware, I wouldn’t even waste time looking for them on U.S. college campuses…..
…the U.S. ranks 21st out of 29 Organization for Economic Cooperation and Development (OECD) countries in mathematics scores, with nearly one-quarter of students unable to solve the easiest level of questions…. In 2000, 28 percent of all freshmen entering a degree-granting institution required remedial coursework”
Source: http://www.edreform.com/_upload/CER_JunkFoodDiet.pdf
The kids in my neighborhood can not even add single digit numbers! At least with the internet they can learn to read, spelling and grammar not so much.
Ben – Thank you for your edits! I have made them in my post.
Bart says:
May 6, 2010 at 1:30 pm
I don’t think you understood the experiment. In the experiment, Wood filtered out the incoming IR from the Sun. Thus, you have no IR coming into the two enclosures. But, the black lining should emit IR, and the IR trapping glass enclosure should therefore become hotter under the Greenhouse hypothesis. It did not, or at least, not significantly. As in the Sun/Earth system, there was no overlap between the incoming and outgoing IR. I’m not hanging my hat on this experimental outcome, just trying to clarify what is being discussed.
You are right, the experiment had a different purpose. I suppose that the none-outcome was mainly a matter of conduction, which removed most of the heat, not by radiation.
CO2 concentration in the atmosphere is correlated with higher temperature in the same way shoe size is correlated with higher income.
Correlation does not equal causation!
I am now reading Climate Confusion (Spencer, 2008) http://amzn.com/1594033455.
I can confirm that this book is concord with solid Feynman class Physics, and I am happy that Pielke Sr. is in the same ballpark.
I am looking forward to read The Great Global Warming Blunder (Spencer, 2010) http://amzn.com/1594033730.
PJP says:
May 6, 2010 at 9:18 am
Here is the reference to the experiment done around 1860 by Tyndall, proving that water, CO2, O3 and other gases were “greenhouse” gases (where “greenhouse” is the wrong description…), thus absorbing IR waves. It is not the reference I was looking for, but a similar experiment, where the re-emission of IR by CO2 was measured in a similar upset by measuring the heat radiation above a flame (without radiation of the flame itself) with and without CO2 addition.
http://en.wikipedia.org/wiki/File:TyndallsSetupForMeasuringRadiantHeatAbsorptionByGases_annotated.jpg
leif,
here’s a really peripheral question. It came up recently (at my work) about BB continuum emissions by gases. The general consensus was that gases can emit continuum bb radiation (at reduced rates) and that is how the solar photosphere works (and by inference – something that goes on within the atmosphere. This is of course not my view – at least at lower T values though it’s obvious there is a continuum emitted by the photosphere – and it isn’t just lines with doppler (or pressure – LOL) broadening. With somewhat limited time here, what I think I found was that the ‘continuum’ which is essentially BB in the photosphere is caused by free electrons and formations of things like H- ions (hydrogen with 2x electrons) and not some sort of gas continuum emission from standard atoms & molecules like H, H2, and He – or other trace metals in the photosphere. Also, mutliple scatterings seem to have an impact but I thought the photosphere was not even a complete pathlength for most of the curve.
Is this correct and if so, where does one find a decent source stating it? Wikipedia and online encyclopedias are not really appreciated and it appears to be beyond the usual modern physics textbooks.
thanks in advance and appologies if this is too far off topic – but it suggests (assuming I’m wrong and there is a straight continuum emitted) that co2 absorption should have much less of an impact than presumed, even when including particulates, dimers, and cloud tops.
Phil. says:
May 6, 2010 at 12:26 pm
“No completely wrong, if a ground state CO2 molecule absorbs a 667cm^-1 photon it’s promoted to the 010 state, there’s nothing to stop that molecule absorbing another 667cm^-1 photon and being promoted to the 020 state, and so on.”
I think Pauli would disagree with you.
Quoting Invariant:
“I can confirm that this book is concord with solid Feynman class Physics”
Commenting:
You remind me of my favorite book – “Surely You’re Joking, Mr. Feynman”.
Just imagine what he would have had to say about all this!
Gail Combs says:
May 6, 2010 at 1:37 pm
Lief it is not the Internet to blame but an educational system that produces “team players” with just enough education to be useful as factory drones… well maybe.
Well, of course, it is primarily the education system [and the US is probably one of the worst among the richer nations]. but afterwards those kids find the Internet and WUWT and find the easier-to-understand [and therefore seductive: “Hey, guess what, even I can understand this stuff, must be right”] pseudo-science as a substitute for the much harder to grasp real science, to wit many posts on this very blog [most of us here know who they are – even if they themselves don’t].
cba says:
May 6, 2010 at 3:52 pm
With somewhat limited time here, what I think I found was that the ‘continuum’ which is essentially BB in the photosphere is caused by free electrons and formations of things like H- ions (hydrogen with 2x electrons)
This is basically correct, but with a twist. The negative H- ions are the cause of the continuum radiation. This was discovered by Wildt in 1938. Until then, the mechanism that is responsible for 95% of the Sun’s radiation was not known. Detailed and difficult quantum mechanical calculation by Chandrasekhar et al. showed that the wavelength dependence and magnitude of the photospheric opacity that the H- ion would have matched the observed photospheric opacity. An opaque body radiates with a continuum spectrum, that is the key. Now H- is formed by the weak electrostatic attachment of a second electron to the nucleus of atomic H, because it is not completely ‘neutral’ as the sole electron does not cancel the proton at all angles around it. The electrons that are attached come from metals such as Na, Mg, and Fe, that have a low ionization potential [that is the twist – and has some implications for stellar evolution because these ‘metals’ did not exist in very early [old] stars] and are thus ionized even at the low temperatures in the photosphere that is not enough to ionize the H atom. So, bound-free H- absorption makes the dominant contribution to the photospheric absorption in the visible and near-infrared, even though there is only one H- ion per 100 million H neutral H atoms. Contrary to common belief, the photosphere is very weakly ionized [less than seawater, in fact]. At longer wavelengths free-free opacity of Hi dominates. So H- makes the photosphere opaque and hence the continuous spectrum.
Richard M says:
May 6, 2010 at 12:02 pm
There’s one thing I have been trying to find with little success. We know the increase in CO2 has led to an increase in biomass, both in oceans and on land. This increased biomass then necessarily utilizes energy which can no longer be used to heat the atmosphere. This is clearly a negative feedback. Is there anyway one could determine what percentage of the W/M2 attributed to CO2 increases is utilized by the added biomass?
This is just a WAG, but perhaps it’s the missing heat rumored to reside in the ocean.
Bart says:
May 6, 2010 at 4:41 pm
Phil. says:
May 6, 2010 at 12:26 pm
“No completely wrong, if a ground state CO2 molecule absorbs a 667cm^-1 photon it’s promoted to the 010 state, there’s nothing to stop that molecule absorbing another 667cm^-1 photon and being promoted to the 020 state, and so on.”
I think Pauli would disagree with you.
If he did he’d be wrong, but I think you’re the one who’s wrong in this case.
Well after finding out that most of the rural and polar stations are not significantly warmer today than in the 1930s (Jones et al land air temperature anomalies only on a 5° by 5° grid-box basis).
And that this picture was somewhat radical changed , in time for the IPCC 2007 report, with the HadCRUT3v Land- and Sea-Surface Temperatures data set, and the Climategate, I have simply have problems in beliving in these datasets.
And the fact that polar regions should warm more than the total global temperature and they dont.
Is it not then a red herring to ask the Critics to explain scientifically something that most probably is not a scientific fact?
I am missing a reference to the works of Henrik Svensmark, who connects the differences in the sun’s magnetic field, cosmic rays and cloud cover, do you not know that theorie, or do you reject it?
Together with the works of Nir Shaviv it explains the earth shifting from the state of “snowball earth” to “tropical earth” with no icecaps and back.
Leif,
that brings another question. This opacity would seem to me to be simply a kirchoff’s law (absorption/emission equality) situation and not some cause of BB emission because it’s opaque. Rather it is indicating sufficient amounts of gas present to provide significant emissions and perhaps scrambled enough to better approximate a BB curve.? Also, do the free electrons play a significant role or only after they are captured into an H- ion? One has the problem in astronomy of the term metals – which can refer to chemical metals like Mg and Fe or they can refer to anything heavy – O, N, C,Si. Your answer seems to indicate periodic table of the elements term metal. If not, this really makes me wonder what one should see looking at a white dwarf or red dwarf remnant from a 1st gen. star that isn’t going to have anything beyond C or O.