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Pielke Sr. and SkS Dialogue Final Summary

Posted on 29 October 2011 by dana1981

The dialogue between Dr. Pielke Sr. and SkS has run its course, for reasons we will discuss below.  The blog posts associated with this dialogue can be viewed here:

Dr. Pielke's final summary of the dialogue can be viewed here; however, it misrepresents the SkS arguments and the discourse in general several times, as we will show.

Anthropogenic Warming

In attempting to re-calculate the CO2 contribution to the net positive radiative forcing, we showed that Dr. Pielke had made a number of errors, and the correct value was close to 50%, consistent with the findings of the IPCC.  Dr. Pielke agreed with some of our corrections, but came up with new, equally incorrect reasons why the CO2 contribution must somehow be significantly less than 50%.  However, although Dr. Pielke seems to still believe the value is lower, he has provided no references which would significantly alter the SkS calculations.  Dr. Pielke claims:

"SkS accepts a lower value of the positive radiative forcing from soot (black carbon), dismisses two other aerosol effects from NRC 2005 and ignores that some of the radiative effect from the added CO2 would have been adjusted for by a warmer climate system since its introduction."

This is simply a mischaracterization of our position.  SkS used the most up-to-date radiative forcing estimate for black carbon, which is larger than the IPCC estimate (and also noted that one previous study estimates the value is higher), did not "dismiss" aerosol effects, and did not "ignore" Dr. Pielke's so-called "adjustment" from a warming climate.  In fact, we noted that Dr. Pielke's "adjustment" (which he did not account for in his own calculations, or justify other than referencing a personal communication) does not apply to our discussion of the radiative forcing and temperature changes over the past century.

Dr. Pielke argued that the current radiative forcing is more important than the change in forcing (though he did not provide an estimate of the current forcing), but we disagree.  A long-term climate change is caused by a change in radiative forcing.  That is why we were interested in calculating the contribution of CO2 and the net anthropogenic forcing to the global warming over the past century.  Dr. Pielke refused to estimate these values, and did not provide any reason to doubt the SkS best estimates of 0.79°C average global surface warming from CO2, and 0.65°C from the net anthropogenic forcing (the discrepancy in the figures being due to cooling from aerosol emissions).

Ocean Warming

About ocean heat content, in his latest blog post, Dr. Pielke claims (emphasis added):

"warming on the upper ocean has been reduced in recent years. SkS spent a lot of time trying to argue that this is not significant and that one needs to perform statistical tests to show it is...I agree we can not say anything about the long-term trends, but to ignore that heating of the upper ocean has mostly stopped ignores the obvious."

Dr. Pielke's recollection here is simply wrong.  We originally raised this issue because Dr. Pielke had claimed on his blog that OHC has not increased whatsoever ("~0 Joules", as he put it) since 2003.  We demonstrated that this claim was false, and Dr. Pielke admitted his error (although he has not revised the erroneous blog post).  However, contrary to Dr. Pielke's account, we specifically noted

"We agree that increase in OHC for the upper 700 meters has slowed in recent years."

Note that while the heating of the upper 700 meters has slowed, the heating of the upper 1500 meters has not, nor has the heating of the upper ocean "mostly stopped," as Dr. Pielke incorrectly claims.  We did not delve into the statistical significance of the reduced upper 700 meter OHC trend, but rather noted that the warming in the deeper oceans has compensated for the slowed upper ocean warming:

"as we discussed in the post above, and Rob P's recent post, and John's post today, heat is also accumulating in the oceans at depths below 700 meters."


Figure 1: Total Global Heat Content from Church et al 2011

Dr. Pielke seemed reluctant to admit that the deeper oceans have warmed, making several statements along the lines of "If there is heat accumulating at depth...if the heat is actually there," and on his blog he continues to focus exclusively on the upper 700 meters of the oceans.  However, as we have noted several times, there is nothing magical about the 700 meter depth.  The ARGO data extends down to 1500 meters, and other studies have measured the yet deeper ocean layers.  The data show that they have warmed, as illustrated in Figure 1.  We are somewhat puzzled as to why Dr. Pielke has such a difficult time accepting these data.

Continued Atmospheric Warming

With regards to the lower tropospheric temperature (TLT) data, Pielke similarly misrepresents the statements made by SkS on the subject.

"with respect to lower tropospheric temperature trends, they similarly conclude that any short-term excursion from a long-term linear warming is “noise” due to natural climate variations.  Maybe they are right. However, to ignore the obvious that the warming of the lower troposphere has halted, when averaged over the time period 1998 (or 2002) to the present, ignores the obvious signal in the data."

Dr. Pielke seems rather confused in this statement, first correctly acknowledging that short-term variations are noise, and then claiming that they are "obvious signal in the data" in the very next sentence!

It's also only possible to say that the TLT warming trend has "halted" if we cherrypick the perfect start date and data set, as Dr. Pielke did.  And once again, contrary to Dr. Pielke's account, we specifically and repeatedly acknowledged that the TLT trend has slowed in recent years (i.e. here and here and here).  We also noted several times that the reduced trend over a short timeframe is not unexpected (see Santer et al. 2011), and in fact when we examine the various short-term temperature influences (i.e. ENSO, solar irradiance, aerosols), the slowed warming is even an expected result.  Rather than examining the causes of the short-term slowing of the TLT warming trend, Dr. Pielke criticized SkS for doing this analysis, saying

"the failure to accept a slowing down of the tropospheric warming, which seems so obvious to me, actually prevents a more constructive discussion with the so-called "skeptics"."

In short, Dr. Pielke seems to believe we should cherrypick data, refuse to examine the causes of short-term temperature changes, and generally lower the quality of our scientific and statistical analysis in order to pander to the so-called "skeptics."  We could not disagree more, and believe Dr. Pielke's is an unscientific approach.

Stratospheric Cooling

Dr. Pielke claims

"Now, what SkS ignored in my questions to them was the lack of cooling in the lower stratosphere since about 1995"

We did not ignore this question - there were many questions going back and forth during our discourse, and if Dr. Pielke asked one about stratospheric cooling, we simply missed it.  In searching back through the dialogue, we were only able to find one brief mention of the stratospheric temperature trend, which we did indeed respond to.

Regardless, this is not a difficult question to address, as many different factors influence stratospheric temperatures, including water vapor, aerosols, incoming solar radiation, ozone etc.  For example, we recommend that Dr. Pielke read Seidel et al. (2011), emphasis added:

"The temporal and vertical structure of these [stratospheric temperature] variations are reasonably well explained by models that include changes in greenhouse gases, ozone, volcanic aerosols, and solar output, although there are significant uncertainties in the temperature observations and regarding the nature and influence of past changes in stratospheric water vapor."

A Word on Attitudes

Throughout the dialogue, Dr. Pielke accused SkS and our commenters of being "snarky."  To this point we have ignored these accusations, because we are interested in discussing science, and accusations about the tone of the dialogue simply serve as a distraction  However, it's worth noting that Dr. Pielke made quite a few "snarky" comments of his own.  Dr. Pielke concludes his latest blog post saying

"I suspect many readers turn off SkS because of the tone they use in the comments."

Frankly, this is an absurd statement.  The tone of comments on SkS in general is among the most civil in the climate blogosphere.  We invite Dr. Pielke to compare the tone in the SkS comments to the tone in the comments of the blog of the man he defends so vigorously, Anthony Watts (whose tone is orders of magnitude more caustic than at SkS), and then to compare the scientific content of the posts. We consider the scientific content to be the most important part of the debate.

Dr. Pielke also accused SkS of reluctance to discuss science.

"Despite a rocky start (e.g. see) they finally engaged in constructive interactions"

We would like to reiterate that this dialogue began with Dr. Pielke falsely accusing SkS of ad hominem attacks on Spencer and Christy.  When we pointed out that the series in question examine the scientific claims of those individuals, and thus by definition are not ad hominem attacks, it was Dr. Pielke who refused to discuss the science contained therein, instead changing the subject and trying to make us chase his Goodyear blimp, which we eventually did.  Our reluctance to do so was obviously not because we are hesitant to discuss climate science, but rather because we expected Dr. Pielke to examine the scientific series which he wrongly attacked (which unfortunately, he never did, as he continued to wrongfully accuse SkS of failing to examine Spencer's scientific research).

We should also note that Dr. Pielke's repeated evasion and unwillingness to answer direct questions was substantially responsible for the argumentative tone of the discussion.  For example, had he simply accepted our corrections to his radiative forcing calculations, rather than coming up with new incorrect reasons why the human contribution must be much lower than 50%, we would have been able to proceed to discuss other issues rather than continuing to argue this point.

Finally, Dr. Pielke claims about one of our weekly cartoons,

"the disclaimer to the contrary in one of the comments, clearly is intended to relate to me "

Several SkS contributors explained to Dr. Pielke that the cartoon was clearly not intended to depict him.  It was merely a strange coincidence that one of the characters in the cartoon (which SkS did not create) was named "Roger" (hardly an uncommon  name).  Unlike Anthony Watts, SkS does not create or publish cartoons which mock specific individuals.

Pielke vs. Pielke

It is well worth reiterating that Dr. Pielke and SkS agree on the importance of reducing CO2 emissions.  As Dr. Pielke put it (emphasis added):

"The emission of CO2 into the atmosphere, and its continued accumulation in the atmosphere is changing the climate. We do not need to agree on the magnitude of its global average radiative forcing to see a need to limit this accumulation. The biogeochemical effect of added CO2 by itself is a concern as we do not know its consequences. At the very least, ecosystem function will change resulting in biodiversity changes as different species react differently to higher CO2. The prudent path, therefore, is to limit how much we change our atmosphere."

Unfortunately, Dr. Pielke and SkS disagree on the approach we should take to reach that goal of emissions reductions.  The climate "skeptic" community has the exact opposite goal - to prevent significant action to reduce CO2 emissions.  In order to achieve that goal, climate "skeptics" spread misinformation and attempt to sow doubt in the minds of the public and policymakers (this includes some of the colleagues Dr. Pielke has so vigorously defended).

SkS believes that the most effective way to achieve the emissions reductions goal is to counteract this misinformation by examining what the body of peer-reviewed scientific literature has to say about it.  Dr. Pielke, on the other hand, seems to constantly try to feed these "skeptics" ammunition for their arguments.  For example, as we have discussed here, Dr. Pielke cherrypicked data in an attempt to argue that TLT and OHC have not increased since 1998/2002/2003/etc. in an attempt to argue that the warming has stopped.  The "skeptic" interpretation of these comments could not be easier to predict - "Dr. Pielke says that global warming stopped a decade ago."  We fail to see how this behavior will help us further the goal of reducing greenhouse gas emissions.

Dr. Pielke also frequently focuses on what we don't know about the climate, for example, quote mining recent statements by various climate scientists and emphasizing uncertainty, concluding (emphasis his):

"These extracts from the Greenwire article illustrate why the climate system is not yet well understood. The science is NOT solved."

Of course the science is "not solved."  Science is never solved.  And there are certainly aspects of the climate system which we do not yet understand well.  But there are also aspects of the climate system which we do understand well, to the point that we BOTH agree regarding the need to reduce greenhouse gas emissions.  As Dr. Pielke admits, we know that CO2 and other greenhouse gases are first order forcings which, if we continue to dump more and more of them into the atmosphere, will continue to cause more and more global warming and climate change.  So what do we gain by inflating the uncertainties, especially when we know uncertainties cut both ways?

We know what the result will be - the "skeptics" will gleefully (and predictably) exploit these uncertainties as an excuse to oppose taking action to address climate change.  In short, Dr. Pielke's behavior undermines his stated goal of reducing greenhouse gas emissions and addressing climate change.  We recommend that Dr. Pielke stop sabotaging his own goal and instead implement a new policy: DNFTD (Do Not Feed The Delayers).

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Comments 51 to 64 out of 64:

  1. Correction- that last should have been 'preceding 10 years' not 8.
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  2. Re: moderators comment to #48 Thanks for the invitation, but life is too busy for me at the moment to commit to a guest post right now. Perhaps a little later? I presume that moderators have access to my email address, so if you want to contact me to suggest what you'd like to see, we can at least discuss it. One other thought has occurred to me with regard to the progress of the discussions with Dr. Pielke. At one point in my past, an employee decided that I should get a one-day session in media training. [No, my participation here has nothing to do with my job.] Scientists often aren't very good at handling the media - the reporter wants to make sure to get "the story", and the scientists need to be taught how to get "the message" out past the reporter, all while making sure that they don't accidentally give the reporter something that The Powers That Be don't want the reporter to know. We were taught to make sure that we keep coming back to "the message", and we were taught techniques to divert attention away from questions we didn't want to deal with. The classic: "that's a good question, Fred, but what we really need to know about is..." In Dr. Pielke's case, he certainly kept coming back to his message about ocean heat content as the primary metric of global warming. He certainly didn't like having others steer the discussion back to things that weren't part of his message, or when people kept pressing for details that he didn't want to (or couldn't) discuss. When completely backed against a wall, he tried to dismiss the topic as "not important", even if it was a topic he had made very public (and very strong) declarations on. My impression was that he did not like the fact that he did not have strong control over the discussions. Contrast this with how SkS has handled things. First of all, SkS strongly encourages comments and discussions of its posts. There are rules (good ones, IMHO), but individuals appear to be given a lot of warnings before major action is taken. In the case of the discussions with Dr. Pielke, SkS has done summaries of the discussions, highlighting areas of agreement, and areas of disagreement. All of this is done with reference to the scientific literature, where available. This process of identifying differences is an essential part of the scientific process. The areas of disagreement are where future research is focused. Sometimes, you can resolve disagreements by finding additional information already in the literature. When you can't, sometimes you can find useful existing data that has not yet been analyzed in a suitable way. If no data exists, you then go in search of funding, and then do the experiments or collect the required data. The more complex the differences, the more sources of data you will need. Rarely will there be one definitive study that resolves the differences - often it can take years, and often the extra data will still be subject to multiple interpretations. For this reason, I find SkS's approach far more constructive than Dr. Pielke's.
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  3. Bob I couldn't agree more. Yours is a very astute and accurate analysis of the exchange with Dr Pielke.
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  4. Speaking of ocean heat content... "In a brief email statement, the Koch Foundation noted that Muller’s team didn’t examine ocean temperature or the cause of warming and said it will continue to fund such research. “The project is ongoing and entering peer review, and we’re proud to support this strong, transparent research,” said foundation spokeswoman Tonya Mullins." Source: "Skeptic’s own study finds climate change real, but says scientists should be more critical," Washington Post, Oct 30, 2011 To access this in-depth article, click here.
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  5. Bob Loblaw @48: 1) IMO the main problem with using OHC as the metric of global warming is that it has no implications for future behavior of the climate system. Whatever the changes in OHC, the climate will continue to change until the energy leaving the top of the atmosphere (TOA) balances with that received from the sun (radiative equilibrium). As heat below the ocean's surface (specifically, the ocean's "skin") makes no contribution to upwelling Infrared radiation, it has no direct effect on the radiative balance at the TOA. In contrast, Global Mean Surface Temperature has an immediate effect on the up-welling IR radiation both by changing the energy of the IR radiation escaping through the "atmospheric window", and, through convection, by changing the temperatures of the gases that radiate IR energy to space. Because the ratio of GMST to radiative flux is robust through history, we can use that ratio to predict an equilibrium GMST for a given change in radiative flux, something measurements of OHC does not permit. It is true that measurement of OHC together with accurate enough measurements of TOA energy flux (up and down) would allow similar predictions on the assumption of a robust climate sensitivity. However, in order to make such predictions, TOA measurements of the absolute value of the radiative flux would need to improve in sensitivity by an order of magnitude (at least). If we ever gain such accurate instruments, then Pielke's argument may make sense on this point; except that historical values would be lacking. 2) A further problem with ignoring GMST is that it is surface temperature, not OHC that drives climate. Of course, for understanding climate and climate change, the full field of global data is far more useful than their average, but that single number still carries useful information, and more useful information than does the equivalent single number representing OHC. That is because the field the single number represents has a more direct impact on climate, and because we have far more observational comparisons of climate effects relating to the GMST than to the OHC. 3) While I agree that SST is a good proxy for OHC for the upper 750 meters, there can be an increase in OHC without an increase in SST. All that is required is a greater energy flux combined with a more efficient mixing of heat to the deeper layers. The later could be provided by stronger winds (for example). The logic here parallels Dr Pielke's claim that the increase in OHC between 750 and 2000 meters cannot have come from the surface because of the relative lack of heat in the 0-750 meter layer. Again, that claim is false. All that is required for it to be false is a more efficient mixing of heat to the deep (below 750 meters) layer, say be ENSO effects.
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  6. Bob Loblaw @52 Very good discussion. Ocean heat content should reflect the integral of all the past heat flux imbalances back to the mythical global 'equilibrium' where there was no imbalance. If less that 10% of the heat energy imbalance is represented by land and atmosphere warming, then the 90% plus in the oceans must be the primary store of heat energy gain on a global basis. Redistribution of this heat energy by the complex circulations, ENSO etc would be measurable by ice melt, and/or temperature warming in one place and cooling somewhere else. It is very difficult to accurately measure ocean heat content and this should be the area of greatest research effort. Tom Curtis @55 "IMO the main problem with using OHC as the metric of global warming is that it has no implications for future behavior of the climate system." Future energy gain is in the future. Heat already gained to date will show somewhere in temperature rise, ice melt etc which has already occurred. If heat comes out of the oceans to warm the land and atmosphere - it will be lost from the oceans, so would not future warming on a global basis be entirely dependent on future heat energy gain?
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  7. A few odds and ends - it has been a busy day, so time is limited. Tom: I'd disagree that OHC content has no implications for future climate. Sea Surface Temperature (SST) is strongly linked to ocean temperature - at least for the mixed layer. How and where in the ocean the heat accumulates affects SST, which affects large parts of the climate system during the period of transition as TOA radiation returns to balance. I agree with your statement of the importance of TOA radiation, and the importance of SST on climate, but personally I think it is unlikely that increased flux of energy into the ocean surface would be exactly balanced by increased flux to depth, so that SST would remain the same. I would more expect that SST would rise, leading to increased flux of heat into the ocean - even if there is increased mixing by factors such as wind. Just a hunch, though. Tom and Victull: one aspect of the idea that OHC be the "primary" metric is that OHC is really mainly answering just one question: where does the heat that accumulates due to the TOA imbalance end up? Measuring OHC really doesn't help a lot to find out how the heat gets into the ocean, and that is the fundamental question for understanding the climatology of the issue, which is what we need to know to make predictions and improve models. To make what might be a bad analogy: the indicator that tells you what illness you have may not tell you what to do to cure it or prevent it - for that you need additional information that helps you understand the disease, not just test for it.
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  8. Bob Loblaw@57 This might be getting off topic but heat gets into the oceans by I guess the normal means of heat transfer - radiation, conduction and convection. The normal 'equilibrium' state of the biosphere bounded by the ocean bottom and land surface and top of the atmosphere would be a heat flux of 0.1W/M2 geothermal heat flowing from the ocean bottom up though the ocean and out at TOA - effectively giving a -0.1W/M2 (cooling) flux at TOA. Otherwise the biosphere would continually heat up over eons and boil the oceans. For the oceans to gain heat, it can only flow globally from the top or sides downward on a global scale even though in some places it might flow upward and others downward to give a net downward. Is there any other explanation?
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  9. Victull - "but heat gets into the oceans by I guess the normal means of heat transfer - radiation, conduction and convection." Nope. A common enough misconception. See SkS post: How Increasing Carbon Dioxide Heats The Ocean". I'm working on an animation with our SkS graphics guru, and will re-write to make it easier to follow, but you should get the general picture.
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  10. Rob@59 I'm not sure why you think the processes in the post How Increasing Carbon Dioxide Heats The Ocean (your link has an extra " at the end) contradict what vitull has said: - radiation reaches the surface from the atmosphere. Visible light will penetrate the water surface and be absorbed at depth, while IR will be largely absorbed right at the surface. (Energy gain to ocean) - visible light will be (partly) reflected at the surface and at depth, and IR will be emitted upward at the surface. (Energy loss from ocean) - turbulence in the atmosphere will carry heat and water vapour either towards or away from the surface (mainly away). This is convective transfer (in normal physics-speak). (Water vapour represents energy because it takes energy to evaporate the liquid). - turbulence within the ocean will transport heat away or towards the surface. This is convective transfer. - the viscous layer at the immediate ocean surface that is discuss in the other post does not have turbulence, but that is where conduction plays a role. Conduction can be up or down, depending on conditions (local gradient), but would be predominantly upward (from ocean depth to surface). Have I left something out? All these fall into victull's "radiation, conduction, and convection". I'd agree that the dominant global, long-term mean source of energy addition into the ocean is radiative, but on a local time-dependent scale, you can have net radiative loss to the atmosphere (e.g. at night), turbulent transfers from the atmosphere as net gains (warm humid overlying air, with condensation), and heat conduction across the viscous layer directed downwards. Perhaps you took victull's statement as one indicating long-term averages, as opposed to my interpretation of it as a general statement of possibilities? Perhaps my comment on the surface energy balance in that post is useful.
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  11. Bob Loblaw - it was this bit: "but heat gets into the oceans by I guess". It is a very common misconception. Perhaps I've misinterpreted his comment, but the "guess" word set off my "spidey sense".
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  12. Bob & Rob @59 &60 Sorry if my 'I guess' seemed cute. It is a result of Amero-Irish language exposure. I figure that you two are more expert than I am on these climate change topics, however I do have some background in heat transfer and thermodynamics. " Perhaps you took victull's statement as one indicating long-term averages" - right on Bob - that is the point I was making. Is not global warming all about long term averages rather than short term variations? If you would indulge maybe a slightly off topic area; I do have one more question for you which has been troubling me. Dr Pielke and others have made much of the slowing in warming over recent years and Dr Trenberth also refers to a stasis in warming. Aerosols, reduced Solar and ENSO - La Nina cycles are suggested as reasons. ENSO - La Nina cycles are usually considered as internal redistributions of heat which is already in the system. In that case they should not contribute to global heating or cooling. If that is not the case then why should ENSO - La Nina not be treated as external forcings just like Solar and Aerosols?
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  13. I was under the impression that ENSO can't be a 'forcing' because it's effectively zero sum. All it can do is create noise.
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  14. Victull @ 62 - my bad. As far as ENSO is concerned we need to differentiate what we are talking about here. You (and Tristan) are quite right that ENSO is an internal redistribution of heat, and therefore cannot cause long-term warming (we happen to obey the laws of thermodynamics on this blog! - to paraphrase Homer Simpson). On shorter timescales, ENSO profoundly affects the global weather. La Nina causes cooling of surface temperatures, and El Nino warming. The bulk of this is due to the exchange of heat in the top 500 metres of ocean, and this is essentially the tilting of the thermocline in the equatorial Pacific. The effect is so large it is global in scale. But the key point is this: over 90% of global warming is going into the oceans, and La Nina is a time of strong ocean warming, even though the surface layer is cool. It's this surface layer that globally affects surface temperature, misleading the average punter into thinking that this "slowdown" in surface temps mean a slowdown in global warming. It isn't - global warming is still "Full steam ahead, both engines!" This will be covered in upcoming posts, because it's an area that's not really well understood by the public at large. But no. you can't treat ENSO as an external forcing because it isn't. The "cool" phases are eventually balanced by the "warm" phases, as heat within the system sloshes back and forth.
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