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SkS Responses to Pielke Sr. Questions

Posted on 21 September 2011 by dana1981

On his blog in response to our post One-Sided 'Skepticism, Roger Pielke Sr. asked SkS to respond to some questions.  We would like to note that these questions are totally unrelated to the initial discussion initiated by Dr. Pielke's unsubstantiated criticism of SkS (see Chasing Pielke's Goodyear Blimp).  However, in the interest of establishing what we hope will be a productive discourse, we have agreed to answer Dr. Pielke's questions.

Dr. Pielke's questions are underlined in the text below, and the answers from SkS follow.

1. Of the two hypotheses below, which one do you conclude is correct? (see Dr. Pielke's post for the two hypotheses offered)

The two aren't mutually exclusive, and both are correct.  CO2 is the dominant radiative forcing causing the current global energy imbalance.

2. Of the two perspectives below [from Mike Hulme], which one do you agree with? (see Dr. Pielke's post for the two perspectives offered)

Again, the two perspectives are not mutally exclusive, and both are correct.  As Hulme notes, they are simply two different framings.  In terms of climate policy, the second framing is probably more appropriate, as addressing climate change will involve more than just CO2 emissions reductions.

3. What is your preferred diagnostic to monitor global warming?

SkS doesn't have a preferred diagnostic - all lines of evidence must be taken into account.  It's important to look at all the data in totality to monitor global warming (surface temperature, ocean heat content, atmospheric temperature, TOA energy imbalance, sea level rise, receding ice, etc.).

What is your best estimate of the observed trends in each of these metrics over the last 10 years and the last 20 years?

10-year trends are generally not statistically significant (see Santer et al. 2011, for example).  The approximate best estimate observed trends for some of these metrics over the last ~20 years are as follows.  TLT: 0.18°C per decade.  Surface temperature: 0.18°C per decade.  Ocean Heat Content (OHC) upper 700 meters: 6.3 x 1022 J per decade.  Sea level rise: 32 mm per decade.  Arctic sea ice volume: -2900 km3 per decade.  Glacier mass balance: -180 mm w.e. per decade.

4. What do the models’ predict should be the current value of these metrics?

The surface temperature change is roughly consistent with model predictions, though perhaps a bit on the low end.  The predicted TLT trend is approximately 0.26°C per decadeSea levels are rising faster and Arctic sea ice is declining far faster than models predict.

OHC in the upper 700 meters increased more than the models expected from 1961 to 1999, and has increased less than models project since 2003. There are a number of factors that may explain the recent discrepancy:

  • as noted above, this is too short of a timeframe for a valid statistical evaluation; 
  • models generally do not take the increases in aerosol emissions over this period into account;
  • the oceans are much deeper than 700 meters, and the so-called "missing heat" may very well reside in the deeper oceans (i.e. see Meehl et al. 2011).

We have discussed this subject previously here and more recently here, taking the deep ocean into account.

One reason that we like to rely on multiple lines of evidence, rather than depend on one single indicator, is that any one can be wrong. The history of the UAH measurements comes to mind: the measurements were in conflict with other methods for tracking temperature change (and with climate model projections) for over a decade; eventually, most of the discrepancy was resolved (in favor of the models) only after very subtle analysis of the physical behavior of the instruments.

5. What are your preferred diagnostics to monitor climate change?

That depends on how "climate change" is defined, but again, it is necessary to look at all lines of evidence and data.

6. Is global warming (and cooling) a subset of climate change or does it dominate climate change?

Again, that depends on how "climate change" is defined.  Long-term global temperature and climate changes are both ultimately caused by global energy imbalances.

Now that we have answered your questions, there are a few issues on which we would like to understand your perspective, Dr. Pielke.

SkS Questions for Dr. Pielke

1. Approximately what percentage of the global warming (increase in surface, atmosphere, ocean temperatures, etc.) over the past 100 years would you estimate is due to human greenhouse gas emissions and other anthropogenic effects?  And the past 50 years?

2. Do you find Spencer, Lindzen, and Christy's arguments that equilibrium climate sensitivity is in the ballpark of 1°C or less for doubled atmospheric CO2 plausible?  If so, how do you reconcile this low climate sensitivity with the paleoclimate record, for example needing to explain ~5°C swings in average global surface temperature between glacial and interglacial periods (i.e. see the figure below from Hansen and Sato 2011)?

Fig 2

3. Do you agree that continuing on our current business-as-usual emissions path presents an unacceptable (in your opinion) risk to the biosphere and to human society in general within the next century?

4. Do you agree that continuing on our current business-as-usual emissions path presents an unacceptable (in your opinion) risk to marine ecosystems in the form of ocean acidification within the next century?

5. Do you think that we should begin to move towards a low-carbon economy, thereby reducing anthropogenic GHG emissions?

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Comments 1 to 50 out of 192:

  1. I am going to make a prediction here. Dr. Pielke is probably going to write long-winded posts (and not provide succinct answers like SkS has done above), he is likely going to obfuscate, focus and elevate uncertainty, he is probably going to focus on land use change and his favourite metric (OHC), and he may even decide to choose some interesting time periods on which to base his conclusions.

    In short, he is going to try and convince people of those things that he believes and thinks are important. What are those one might ask? See here for his list of conclusions about the climate system and policy. That is, he appears to have made up his mind already (i.e., uses the title "conclusions"), and appears to have the problem pretty much all figured out. I'll let readers come to their own conclusions.

    I am more than happy for Dr. Pielke Sr. to prove me wrong. In fact, I hope that he does.
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  2. Other than a quote by McKitrick, I haven't seen much discussion of Dr. Pielke's overemphasis on land use. Some critiques of his claims.

    Bizarre Rewriting of History

    Klotzbach ad Nauseam

    Pielkes all the way down, Revisited

    Perhaps there could be an expansion of the land use category. Roger's Ruses?

    As Albatross indicates, expect some long-winded and convoluted dancing to the questions posed. Possibly related, his colleague Anthony Watts posted a Fox News interview with Dr. Pielke some time back. I say "possibly" because the video has been restricted for public viewing.

    Anthony Watts: Dr. Roger Pielke Sr. to be on Fox Business News

    But we always have the astute commenters of the "excellent" (as Dr. Pielke calls it) WUWT blog to give an accurate representation of the interview. Some quotes:

    "In just a couple of minutes Dr. Pielke made the essential point that you cannot regulate the Earth’s climate by manipulating CO2.

    This point absolutely destroys the basic premise underlying so-called ‘climate’ legislation (and the EPA decision that CO2 is a ‘pollutant’)."

    "I think that Dr. Pielke gave a very politically astute interview. Any politician and any student of the vocabulary used by politicians will recognise a perfectly delivered slap-down of the appointment of Karl’s appointment. It was given in a measured, calm and rational manner making it even more devastating.

    Well said, Dr. Pielke. The opponents of CAGW need spokesman like you, the very antithesis of the hysterical pro-AGW propagandists."

    "His main message was that Tom Karl was the wrong man to lead Obama’s new climate centre, as he would stifle the freedom of the team to look at all aspects of the science.

    He also indicated that reducing CO2 was not the answer and that the money would be better spent identifying areas of risk of drought, for example and spending money to mitigate the effects."
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  3. NewYorkJ @2,

    Thanks for posting those links-- do you have more? From the first link:

    "I've got a lengthier post in the works, but since Roger Pielke Sr is demanding a response..."

    Dr. Pielke appears to like demanding things and asking others to answer his his carefully crafted questions.
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  4. Albatross (#3),

    The 2nd link from Nov. 2009 might have been the follow-up, or maybe this post:

    But they also laughed at Bozo the Clown

    Dr. Pielke Jr. (-snip-) gets into tribal discussions and tone. No surprise.

    On global warming metrics, trends, and deep ocean heat, there's a new paper out, discussed here:

    Deep Oceans Can Mask Global Warming for Decade-Long Periods
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    Moderator Response: Let us not get too excited.
  5. This is slightly off topic but maybe not so much, since Dr. Denning (see below) might well be speaking to Drs. Pielkes.

    This is Scott Denning's enlightening and passionate talk (v short) at the....Heartland Institute pseudoscience climate conference. For those that might wish to resist looking at such a thing, Dr. Denning is a proper scientist and makes a great job of skewering the self-defeating bluster of quite a number of types of pseudoskeptics. Highlighting this and its implication would almost be worth a thread of its own...
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  6. Looks like many of the questions were designed for entrapment. I'm amazed there wasn't "do you still beat your wife?"
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    Moderator Response:

    [John Hartz] Which set of questions are you referring to?

    [Daniel Bailey] Inflammatory struck out.

  7. In my opinion, the first five posts should be withdrawn or deleted because Dr. Pielke has not yet responded to Dana's article. It's rather cheeky to assume that one knows in advance what Dr. Pielke's response will be.
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  8. John (Hartz) my post (and this may be true of some of the others) is (a) a highlight of what I imagine many posters would find very useful and relevant, and (b) refers to Drs Pielke in reference to the general policies of these individuals.

    I do agree with your sentiment, but in that case it might have been better to put an embargo on comments on this thread until Dr Pielke responded. If you open a thread for comments you can't not expect to receive them...!
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    Moderator Response: [John Hartz] Because I am a relative newcomer to the ranks of SkS Moderators, I have yet to delete anyone's posts on a comment thread. I would, however, point out that you began your post with "This is slightly off topic..." Otherwise, your points are well taken.
  9. I will note that the recent increase in 'skeptic' blogs attacking SkS is actually a compliment - Bishop Hill, Pielke, Watts, JoNova, etc., are taking the information here seriously enough to denigrate it.

    That said, I would encourage moderation in the rhetoric in return. When someone without an axe to grind comes upon a discussion, the person ranting is likely to be dismissed. I will always treasure the episode on JoNova's blog where one of the regular skeptics was told by the site moderators to tone things down, as his accusations of 'liar!!!' were making me look good.

    Let's take the high road, eh?
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  10. Currently, on Bishop Hill Blog, SS is being accused of rewriting history in the good old Stalinist way.

    http://bishophill.squarespace.com/blog/2011/9/20/cooking-the-books.html#comments

    Would one of the mods care to comment?
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    Response: [John Hartz] The Bishop Hill post is being reviewed by the SkS author team as we speak.

    [John Cook] I've posted a response in the Bishop Hill comments thread.
  11. My response and answer to your questions might be clearer in my weblog post on this but I have entered it here too.


    Dr. Pielke's questions are underlined in the text below, and the answers from SkS follow.

    1. Of the two hypotheses below, which one do you conclude is correct? (see Dr. Pielke's post for the two hypotheses offered)

    The two aren't mutually exclusive, and both are correct. CO2 is the dominant radiative forcing causing the current global energy imbalance.

    R.Pielke Sr. Response -

    First, let me thank you for moving on to actual science issues.

    In response to your first answer, they actually are separate hypotheses and only one of them can be correct.

    We discuss this in

    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.
    http://pielkeclimatesci.wordpress.com/files/2009/12/r-354.pdf

    where we wrote

    "Hypotheses 2a and 2b are two different oppositional views to hypothesis 1. Hypotheses 2a and 2b both agree that human impacts on climate variations and changes are significant. They differ, however, with respect to which human climate forcings are important.......... we suggest that the evidence in the peer- reviewed literature (e.g., as summarized by National Research Council (NRC) [2005]) is predominantly in support of hypothesis 2a, in that a diverse range of first-order human climate forcings have been identified."

    "We therefore conclude that hypothesis 2a is better supported than hypothesis 2b, which is a policy that focuses on modulating carbon emissions. Hypothesis 2b as a framework to mitigate climate change will neglect the diversity of other, important first- order human climate forcings that also can have adverse effects on the climate system. We urge that these other climate forcings should also be considered with respect to mitigation and adaptation policies."

    and

    "The evidence predominantly suggests that humans are significantly altering the global
    environment, and thus climate, in a variety of diverse ways beyond the effects of human emissions of greenhouse gases, including CO2. Unfortunately, the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment did not sufficiently acknowledge the importance of these other human climate forcings in altering regional and global climate and their effects on predictability at the regional scale. It also placed too much emphasis on average global forcing from a limited set of human climate forcings.

    2. Of the two perspectives below [from Mike Hulme], which one do you agree with? (see Dr. Pielke's post for the two perspectives offered)

    Again, the two perspectives are not mutally exclusive, and both are correct. As Hulme notes, they are simply two different framings. In terms of climate policy, the second framing is probably more appropriate, as addressing climate change will involve more than just CO2 emissions reductions.

    R.Pielke Sr. Response -

    If the second framing is more appropriate, we have made progress towards agreement as that framework fits with hypothesis 2a. I also suggest you contact Mike Hulem for his view whether both perspectives can be "correct".

    3. What is your preferred diagnostic to monitor global warming?

    SkS doesn't have a preferred diagnostic - all lines of evidence must be taken into account. It's important to look at all the data in totality to monitor global warming (surface temperature, ocean heat content, atmospheric temperature, TOA energy imbalance, sea level rise, receding ice, etc.).


    R.Pielke Sr. Response -

    Global warming or cooling involves changes in Joules of heat in the climate system. This involves changes in heat in the oceans, land, atmosphere and cryosphere. As concluded by Jim Hansen and others, the ocean is by far the component of the climate system where the large majority of this heating and cooling occurs. Receding ice, surface temperature, atmospheric temperatures make up only a relatively small portion of global warming and cooling.

    What is your best estimate of the observed trends in each of these metrics over the last 10 years and the last 20 years?

    10-year trends are generally not statistically significant (see Santer et al. 2011, for example). The approximate best estimate observed trends for some of these metrics over the last ~20 years are as follows. TLT: 0.18°C per decade. Surface temperature: 0.18°C per decade. Ocean Heat Content (OHC) upper 700 meters: 6.3 x 1022 J per decade. Sea level rise: 32 mm per decade. Arctic sea ice volume: -2900 km3 per decade. Glacier mass balance: -180 mm w.e. per decade.

    4. What do the models’ predict should be the current value of these metrics?

    The surface temperature change is roughly consistent with model predictions, though perhaps a bit on the low end. The predicted TLT trend is approximately 0.26°C per decade. Sea levels are rising faster and Arctic sea ice is declining far faster than models predict.

    OHC in the upper 700 meters increased more than the models expected from 1961 to 1999, and has increased less than models project since 2003. There are a number of factors that may explain the recent discrepancy:

    as noted above, this is too short of a timeframe for a valid statistical evaluation;
    models generally do not take the increases in aerosol emissions over this period into account;
    there is a wide range of estimates of upper 700 meter OHC trend since 2003, varying by nearly two orders of magnitude; and the oceans are much deeper than 700 meters, and the so-called "missing heat" may very well reside in the deeper oceans (i.e. see Meehl et al. 2011).
    We have discussed this subject previously here and more recently here, taking the deep ocean into account.

    One reason that we like to rely on multiple lines of evidence, rather than depend on one single indicator, is that any one can be wrong. The history of the UAH measurements comes to mind: the measurements were in conflict with other methods for tracking temperature change (and with climate model projections) for over a decade; eventually, most of the discrepancy was resolved (in favor of the models) only after very subtle analysis of the physical behavior of the instruments.

    R.Pielke Sr. Response -

    The oceanographers who work with the ocean heat data are convincing (at least to me and a number of other colleagues) that since the completion of the Argo network, it is a robust metric (within defined uncertainty bars) such as Josh Willis placed on the figure he provided me for the article

    Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55. http://pielkeclimatesci.wordpress.com/files/2009/10/r-334.pdf

    5. What are your preferred diagnostics to monitor climate change?

    That depends on how "climate change" is defined, but again, it is necessary to look at all lines of evidence and data.

    R.Pielke Sr. Response -

    You avoided answering this question. This is actually an essential issue to resolve. The NRC (2005) report [http://www.nap.edu/openbook.php?record_id=11175&page=200] defines climate change as

    "The system consisting of the atmosphere, hydrosphere, lithosphere, and biosphere, determining the Earth’s climate as the result of mutual interactions and responses to external influences (forcing). Physical, chemical, and biological processes are involved in interactions among the components of the climate system. "

    This is much broader than just global warming and cooling. Please clarify your view.

    6. Is global warming (and cooling) a subset of climate change or does it dominate climate change?

    Again, that depends on how "climate change" is defined. Long-term global temperature and climate changes are both ultimately caused by global energy imbalances.

    R.Pielke Sr. Response -

    The recognition that climate changes can occur without any global energy imbalance is central to the much needed broader view of how humans are altering the climate system. Please clarify what is "climate change" in your view.

    Now that we have answered your questions, there are a few issues on which we would like to understand your perspective, Dr. Pielke.

    SkS Questions for Dr. Pielke

    1. Approximately what percentage of the global warming (increase in surface, atmosphere, ocean temperatures, etc.) over the past 100 years would you estimate is due to human greenhouse gas emissions and other anthropogenic effects? And the past 50 years?

    This is a good question. It is a still incompletely understood mix of a variety of human caused radiative forcings (e.g. CO2, methane and several other greenhouse gases, land use/land cover change, black carbon (soot), sulphates, and other aerosols) and natual climate variations.

    Several years ago I did a back of the envelope estimate and came up that ~26% of the positive radiative forcing was from CO2; see slide 12

    in

    Pielke, R.A. Sr., 2006: Regional and Global Climate Forcings. Presented at the Conference on the Earth’s Radiative Energy Budget Related to SORCE, San Juan Islands, Washington, September 20-22, 2006. http://pielkeclimatesci.wordpress.com/files/2009/09/ppt-69.pdf.

    This number certainly changes through the last 100 and the last 50 years, and remains uncertain.

    The complexity of these radiative forcings is discussed in some detail in NRC (2005) -
    http://www.nap.edu/openbook/0309095069/html/. Despite the vigor with which you criticize Roy Spencer, he actually has been instrumental in elevating our awareness that natural variations in cloud cover, as a result of temporal variations in atmospheric circulation features, as causing long term variations in the TOA radiative imbalance.

    2. Do you find Spencer, Lindzen, and Christy's arguments that equilibrium climate sensitivity is in the ballpark of 1°C or less for doubled atmospheric CO2 plausible? If so, how do you reconcile this low climate sensitivity with the paleoclimate record, for example needing to explain ~5°C swings in average global surface temperature between glacial and interglacial periods (i.e. see the figure below from Hansen and Sato 2011)?

    I do not find the glacial and interglacial periods as useful comparisons with the current climate since when we study them with models, they have large differences in imposed terrain (e.g. massive continetal glaciers over the northern hemisphere which will alter jet stream features, for example).

    In any case, I find the discussion of the so-called "climate sensitivity" by all sides of this issue as an almost meaningless activity. I posted on this in

    So-Called “Climate-Sensitivity” – A Dance On The Head Of A Pin -
    http://pielkeclimatesci.wordpress.com/2011/09/09/so-called-climate-sensitivity-a-dance-on-the-head-of-a-pin/

    3. Do you agree that continuing on our current business-as-usual emissions path presents an unacceptable (in your opinion) risk to the biosphere and to human society in general within the next century?

    Of course. 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.

    By continuing to argue on global warming and its magnitude, I feel you, and others, are missing an opportunity to build up a larger consensus on how to properly deal with the myraid ways we are altering the climate and the environment, in general. Even if there were no global warming (or even cooling) in the coming decades, we still need to limit how much we change the environment (including land use change, nitogren deposition, CO2 etc).

    4. Do you agree that continuing on our current business-as-usual emissions path presents an unacceptable (in your opinion) risk to marine ecosystems in the form of ocean acidification within the next century?

    Regardless of whether we reduce the alkalinity of the oceans (since there may be buffering from the added CO2 through mixing from below) we will be altering ecosystem function both in the oceans and in the atmosphere. Since we do not know the consequences of doing this, the smart thing to do is to work towards reducing the extent we alter the chemisty of the oceans and the atmosphere.

    5. Do you think that we should begin to move towards a low-carbon economy, thereby reducing anthropogenic GHG emissions?

    I am very much in favor of energy sources which minimize the input off gases and aerosols into the atmosphere. Much of my career has been involved with reducing air pollution (both in research and in policy). What we should move towards is an economy with as small a footprint on the natural environment as possible.

    In terms of how to do this with respect to carbon emissions, I completely agree with my son's perspective as he presents in The Climate Fix - http://theclimatefix.com/
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    Moderator Response: [John Hartz] Thank you for your prompt response. To make it easier for everyone to follow your response, would it be OK if we were to bold face your set of questions to SkS and the set of SkS questions to you?
  12. Dr. Pielke

    About your suggestion that SkS speak to Mike Hulme directly, I would point out that Hulme developed six ways of framing the phenomenon of climate change. He said this about those framings:

    "These six frames around climate change all attract powerful audiences, interests and actors in their support. All of them – with the exception of climate change as mostly natural – would be broadly consistent with the scientific knowledge assessed by the Intergovernmental Panel on Climate Change."

    Source: "You’ve been framed: six new ways to understand climate change," by Mike Hulme, The Conversation, July 5, 2011. To access this post, click here

    To the best of your knowledge, has Hulme changed his mind since the posting of his paper?
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  13. Radiative forcing from IPCC AR4

    Might want to also consider

    Carbon dioxide emissions and their associated warming could linger for millennia

    Given that IPCC projections tend to focus most closely on the next 100 years, seems they aren't grasping the full long-term impacts of CO2 emissions.

    At any rate, I don't see how anyone could state the IPCC is at odds with Hypothesis 2a, but Dr. Pielke is free to make his case.
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  14. Dr Pielke @11, the two hypotheses presented by you for your first question may be intended to be contraries, but in fact they are not. The are:

    "Hypothesis 2a: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.

    Hypothesis 2b: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and are dominated by the emissions into the atmosphere of greenhouse gases, the most important of which is CO2. The adverse impact of these gases on regional and global climate constitutes the primary climate issue for the coming decades."


    I have bolded the differences between the two hypotheses. You should note that:

    a) 2a only refers to CO2 explicitly, which means that for the purposes of 2a other GHG such as CH4 and NO2 are distinct "first order climate forcings". In contrast, in 2b CO2 is grouped with all other GHG and declared to be dominant. Consistent with that, the sum of all GHG forcings in 2a could be dominant even though CO2 by itself is not.

    b) 2a makes no declaration as to whether CO2 (or all GHG) represent a dominant forcing or not. As such it does not contradict the claim that the sum of all GHG is dominant, it merely asserts that there are other significant forcings, and hence does not contradict 2b.

    c) The term "dominant" in 2b is vague, and may indicate any of the following:
    - That the GHG forcing is greater than any other individual forcing;
    - That the GHG forcing is greater than the sum of all other individual forcings;
    - That the GHG forcing is much greater than the sum of all other forcings; or
    - That the GHG forcing is sufficiently greater than the sum of all other forcings that for practical (policy) purposes, the other forcings can be ignored.

    The first two of these alternatives are certainly consistent with the spirit of 2a, and only the last contradicts the spirit (though not the letter) of 2a.

    Consequently, if you intend that the two hypotheses be contraries, you need to tighten up your language substantially.

    To that purpose, perhaps you could indicate if you disagree with the relative forcings indicated by the IPCC AR4, and if so by how much. They certainly seem to indicate that the sum of GHG is currently the dominant forcing of climate change:



    I note in passing that the two hypotheses from Mike Hulme are also not contraries, whatever his, or your intentions, and fail to be contraries for very similar reasons to those above.
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  15. To avoid confusion, I wonder if we can all focus on one question/response at a time. Maybe topic 1 would be a rational place to start? Discuss that until there's no more juice; and then move to the next?
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  16. (It looks like Tom Curtis is already starting on that approach, so I'll get out of his way.)
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  17. John Hartz - The term "broadly consistent" covers a lot of territory. I certainly would not write the IPCC connection that way. Regardless, however, his key conclusion is that, as he writes [what are really a statement of hypotheses 2a and 2b)


    ”….these two different provocations – two different framings of climate change – open up the possibility of very different forms of public and policy engagement with the issue. They shape the response.

    The latter framing, for example, emphasises that human influences on climate are not just about greenhouse gas emissions (and hence that climate change is not just about fossil energy use), but also result from land use changes (emissions and albedo effects) and from aerosols (dust, sulphates and soot).

    It emphasises that these human effects on climate are as much regional as they are global. And it emphasises that the interplay between human and natural effects on climate are complex and that this complexity is novel.”

    A focus on the radiative forcing of added CO2 as the dominate environmental threat is not supported by the scientific evidence. Policies that focus on that single issue which result in negative effects on other environmental and social concenrs is not good policy, in my view.
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  18. NewYorkJ - The 2007 IPCC focuses on CO2 mitigation; e.g. see

    Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)

    Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

    The physical science basis focuses on added greenhouse gases, and a top-down global perspective as given in

    Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)

    Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

    I am pleased, however, that you see the need to move towards hypothesis 2a.
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  19. Tom Curtis - I invite you to reframe into two "oppositional" testable hypotheses. The 19 co-authors of our paper [all Fellows of the AGU] concluded the ones we presented are distinct. However, I welcome to use your comment above to do this if you feel they are not separate enough.

    On your comment,

    "To that purpose, perhaps you could indicate if you disagree with the relative forcings indicated by the IPCC AR4, and if so by how much. They certainly seem to indicate that the sum of GHG is currently the dominant forcing of climate change"

    this is only true from the IPCC figure in terms of the global average radiative forcing, even if you accept their values. You stated that the "the sum of GHG is currently the dominant forcing of climate change". As one counter example, in terms of their role on weather patterns, and thus on climate, see

    Matsui, T., and R.A. Pielke Sr., 2006: Measurement-based estimation of the spatial gradient of aerosol radiative forcing. Geophys. Res. Letts., 33, L11813, doi:10.1029/2006GL025974.
    http://pielkeclimatesci.wordpress.com/files/2009/10/r-312.pdf

    In terms of CO2, and its fractional role in terms of the global average radiative forcing, I provided my estimate, based on the available literature, in my answer to one of
    dana1981's questions [note: it would be nice to know who dana1981 is; it is unfortunate that anyone feels they need to be annoymous].
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  20. Dr. Pielke,

    Hypothesis A states "the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2)."

    which would be consistent with IPCC AR4. Hypothesis A does not state what the other influences besides CO2 are, and does not speak to land use changes, as you assume above.

    As you can see from the radiative forcing figure referenced in #13 and #14 (also SPM.2 in the Summary for Policymakers WG1), the human influences include CO2, N2O, Halocarbons, ozone, black carbon, and aerosols.

    The IPCC and the evidence is also consistent with CO2 being the single-most important anthropogenic contributor and is consistent with Hypothesis B (although as I've noted in #13, the scope of the IPCC report tends to inevitably underestimate the severity of long-term impacts of the human addition to atmospheric CO2).

    What I'm not sure you're understanding (but what Hulme appears to understand) is that these statements are not remotely close to being Mutually exclusive.
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  21. From a more practical, less philosophical perspective: I think we can agree that there are land-use issues as well as atmospheric additives that impact on climate. Land-use issues are under more local control, whereas atmospheric additives need to be considered from a global perspective as well. I don't think we can afford to dismiss any of them.
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  22. Your answer for glacier mass balance is not correct the mass balance loss as reported to the WGMS and by the WGMS and noted by decade for the BAMS state of the climate series in 2010 is greater than noted above. In the 1980's it was -180 mm per year not decade. In the 1990's it was -370 mm per year, in the 2000's it was -630 mm per year.
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  23. Dr. Pielke,

    Dana1981's full name is at the bottom of the rebuttal articles that he writes. e.g. Not So Cool Predictions.

    (written by Dana Nuccitelli [dana1981])

    You do realize that casting aspersions on the content based on the pseudonymity of the author is an ad hominem, right?
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  24. I agree with John Hartz
    I think the replies to Dr Pielke's questions and the SkS questions put to him are sensible and well considered. Comments and responses to both will hopefully prove instructive and interesting - though I have always regarded both Pielkes as "skeptics". This of course does not mean the product of a SkS-Pielke dialogue will be predictable - but will it be fruitful?
    0 0
  25. Something we can all agree on:

    The Skeptical Science Team (About -> Team) includes a diverse range of contributors, including, but not limited to, John Cook.
    0 0
  26. Dr. Pielke, I am not anonymous. As Bibliovermis notes in #23, sometimes I include my full name, sometimes I don't. However, my background information is provided in the Skeptical Science Team link provided by NewYorkJ in #25.
    0 0
  27. I should also note that while I drafted up this post and contributed significantly to it, a number of SkS contributors provided input as well. It was another consensus effort.
    0 0
  28. I would advise all to not pay the least attention to the anonymous thing. It is a common tactic used at WUWT to avoid dealing with the substance of comments.

    SkS comment policy has no restrictions on the use of real names vs. screen names. As far as I can remember, no comment here was ever dismissed on the basis that the poster was anonymous, regardless where his/her opinion leaned. Of course, one can decide to ignore the content of a comment, even if perfectly valid, only because the commenter remains anonymous; it is a choice everyone is free to make.

    Considering the insults and threats from skeptics that are not so unusual in this debate, I find it perfectly understandable also that some would choose to remain anonymous.
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  29. Dr Pielke @19, as you are the author of the supposed dichotomy, it is for you to reformulate the dichotomy, not me. As an initial step, you can make the following (highlighted) changes to make the to statements formally contraries:

    "Hypothesis 2a: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2) but not dominated by, emissions into the atmosphere of greenhouse gases, the most important of which is CO2. Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades.

    Hypothesis 2b: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and are dominated by the emissions into the atmosphere of greenhouse gases, the most important of which is CO2. The adverse impact of these gases on regional and global climate constitutes the primary climate issue for the coming decades."


    As you also seem to be defending the claim that regional effects are more significant than global effects, you may wish to explicitly state that as part of 2a. Finally, you need to clarify what you mean by "dominate". As I do not know your thinking I cannot do that for you. However, of the four possible meanings in my post, I feel confident in stating that most commentators here would reject 2b if "dominate" is interpreted as "That the GHG forcing is sufficiently greater than the sum of all other forcings that for practical (policy) purposes, the other forcings can be ignored". I suspect most would also consider a gloss of "dominate" as "That the GHG forcing is greater than any other individual forcing" as being too weak.

    Having said that, neither is entirely satisfactory as stated in that they do not sufficiently discriminate between positive and negative effects, and gross and net effects. Specifically, it is clear IMO that the absolute value of the net forcing of GHG is greater than the absolute value of the net aerosol forcing; but it is may be less than the sum of the absolute values of the gross effects (positive and negative) of aerosols.

    Further, given the distinction between global and regional effect is important to your understanding of dominance, it is not certain any of my glosses captures even your approximate meaning.

    As it is you who asked the question, it is for you to clarify these points.
    0 0
  30. Dana Nuccitelli - Thanks for clarifying.
    0 0
  31. With regard to anonymity of comment, it is the simple fact of the matter that publicly speaking out on AGW in defiance of the various "skeptical" misinformation machines has resulted in climate scientists being subject to various forms of public harassment including, but not limited to abusive emails, death threats, and illegal hacking and distribution of private correspondence. Dr Pielke has not, to my knowledge, condemned such acts, and does continue to associate with people who have endorsed them to various degrees. This should not be read as approval, but it is inconsistent with any vehement disapproval of such tactics. To object to people choosing to not make themselves targets of abuse, death threats and illegal hacking is therefore, disingenuous at best, and hypocritical at worst. Given Dr Pielke's stated concerns about anonymity, can we expect from him a clear condemnation of those like Anthony Watts and Christopher Monckton who variously practise or endorse various (though not necessarily all) of the above forms of harassment?
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  32. Tom Curtis

    If you feel this separates them better, lets use these two hypotheses

    Hypothesis 2a: Although the natural causes of climate variations and changes are important, the human influences on regional climate are significant and involve a diverse range of first-order climate forcings, including, but not dominated by, emissions into the atmosphere of greenhouse gases including CO2. Most, if not all, of these human influences on regional climate will continue to be of concern during the coming decades.

    Hypothesis 2b: Although the natural causes of climate variations and changes are undoubtedly important, the human influences on regional climate are significant and are dominated by the emissions into the atmosphere of greenhouse gases including CO2. The adverse impact of these gases on regional climate constitutes the primary climate issue for the coming decades."

    Please try to wordsmith further is you feel edits are still needed. I conclude (as Mike Hulme also agrees), policy responses would differ significantly depending on which hypothoesis is not rejected. From my view, and that of an increasing number of my colleagues, the second hypothesis has been rejected.
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  33. It is interesting to see that Dr Pielke thinks that climate sensitivity is not important (Drs Spencer and Lindzen might wish to disagree). Climate senstivity tells us how much the world is warming in relation to the added CO2, and whether this warming is going to continue into the future. Temperature increases are logcally linked to many of the key impacts of climate change - increased severe precipitation events (water vapour), more intense droughts (heat and drying), snow and ice loss (water availability, albedo), sea level rise. These are all observed. Failures in GCM estimates of regional climate (claimed in Pielke et al's 2011 manuscript) is not an excuse to ignore the observed trends in snow, ice, water vapour, sea level and extreme events. These trends will be worse with high climate sensitivity.

    All of these changes have very real local effects, and will impact your decisions whether you're a Texan or Pakistani farmer, or if your water comes from dwindling snows, or if you live within a metre or two of sea level, for example. If climate sensitivity were low, we'd have little reason to think that the magnitude of each of these products of higher temperature would be likely to increase in the near future. As sensitivity is high, clearly demonstrated by a wide variety of sources (including the important palaeoclimate and geological-scale estimates that incorporate all feedbacks), summarised in Knutti and Hegerl 2008, we have extremely good reasons to believe that these impacts will increase as global temperature continues to rise. It's a pity Dr Pielke does not think climate sensitivity is important, as it would help him to encourage policymakers to develop more effective adaptation and mitigation strategies.

    I would fully endorse Tom's comment in #31 re threats to individuals, and would be interested in Dr Pielke's response.
    0 0
  34. Dr. Pielke, #32:

    I can't get very excited about the word-smithing that's been going on so far.

    I stick with what I said at #21.
    0 0
  35. I propose we declare the topics of anonymity and harassment as "off topic."
    0 0
  36. Dr. Pielke - I have to strongly disagree (as I have before, on other venues) with your emphasis on regional effects over global effects. That is only reasonable if the regional variations are sufficient to mitigate the global effects of rapid climate change.

    There are certainly huge variances across different regions of the world, but if the average of those regions change - with concomitant effects/costs on agriculture, sea level of coastal regions (where most of humanity resides), etc., regional variations will certainly not save us those costs. There's certainly no evidence for regional variations overriding global effects in the majority of the areas that are/will be affected.

    And, in fact, mitigating the global effects will mitigate regional changes as well.

    ---

    My 2 cents on the anonymity issue? I'm not interested in argument by authority, implied or otherwise - I would much rather people judge what I say by content.
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  37. Dr Pielke @32, unfortunately I cannot accept either of your reworded hypotheses, which now constitute a false dichotomy. Specifically, the most important challenges in the coming century are the global issues of enhanced GHG forcing and ocean acidification. This perspective is not represented by either of your two amended hypotheses.

    With respect to Neal King (@34), I think the word-smithing is important. As originally stated, the vague distinction encouraged people to see denial of 2a as the unreasonable assertion that non-GHG forcings, and regional effects are irrelevant for policy purposes. Regardless of Dr Pielke's intentions if formulating the hypothesis, we all know there are many "skeptics" unscrupulous enough to try and turn that vagueness into an ad-hominen attack on the consensus understanding of climate science. Dr Pielke's further amended framing of the issue, in contrast, precludes a global focus on what is fundamentally a global problem.

    Further, I believe that Dr Pielke's difficulty in framing the two hypotheses stems from an unwarranted assumption that certain commonly recognized facts are inconsistent with the consensus understanding of climate science. By not consistently and untendentiously framing the issue, he sneaks those assumptions into the discussion with out having to explicitly formulate and defend them.
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  38. Okay, I am curious. If GHG is not the main forcing, then the only other candidate "forcing" that I can think of would be a reduction in industrial aerosols since 1945 if this can be regarded as a forcing. Its not particularly useful forcing since we dont want to make the air dirty and the aerosols are associated with GHG gas release anyway.
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  39. Tom Curtis and Dr. Pielke:

    You may choose to argue fine differences of meaning between your formulations of dichotomy. What I am failing to see is any value-add over what I'm saying right here:

    "I think we can agree that there are land-use issues as well as atmospheric additives that impact on climate. Land-use issues are under more local control, whereas atmospheric additives need to be considered from a global perspective as well. I don't think we can afford to dismiss any of them."
    0 0
  40. Given Dr. Pielke's statements what would people think of putting together a joint statement from "warmists" and "skeptics" on the need for alternative energy development and moving toward a low carbon economy?
    0 0
    Moderator Response: [John Hartz] SkS is all about getting the science right, not about representing a particular point of view.
  41. Readers,

    While discussing hypotheticals and semantics of carefully crafted hypotheses is intriguing, it is for the most part not constructive. And despite claims to the contrary by Pielke et al. (2009), the hypotheses being discussed are not helpful in expediting taking meaningful action on AGW. In fact, I would argue that in this case the hypotheses were presented to fabricate debate, exaggerate uncertainty and foster doubt.

    With regards to the "hypotheses" presented in Pielke et al. (2009) In his oral testimony to the House of Representatives Energy and Commerce Committee hearing on "Climate Science and EPA’s Greenhouse Gas Regulation" in March, 2011, Dr. Pielke is on the public record saying:

    "With respect to climate change, in 2009 18 Fellows of the American Geophysical Union accepted an invitation to join me in a paper where we discussed three different mutually exclusive hypotheses with respect to the climate system:"

    And

    "Hypothesis 2b is the IPCC perspective. In our EOS paper, we concluded that only Hypothesis 2a has not been refuted."

    He then provides this citation:
    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.

    Dr. Pielke appeals to his own authority and that of the AGU ("18 Fellows of the AGU") when he discusses the where the hypotheses first appeared. Now the way that is presented to the casual reader it sounds looks very much like a citation for a journal paper does it not? Academics and research scientists alike mean "journal paper" when they say "paper". Well that 2009 citation is not a "journal paper", it was published in the "Forum" section of EOS, the official newspaper of the AGU. The guidelines for EOS are clear they say that:

    "Eos does not publish original research results"

    And

    "Eos is a newspaper, not a research journal"

    Now maybe things were different when their opinion piece was published in EOS in 2009. If so my concerns are unfounded, and I sincerely apologize for bringing it up. But if not, it could be fairly argued that Dr. Pielke is misleading many people (inlcuding members of the House of Representatives) into thinking that these hypotheses appeared in a peer-reviewed paper in an AGU journal. As a member of the AGU (American Geophysical Union) I take strong exception to him doing so, and I urge him to address this matter.

    Additionally, Dr. Pielke does not in his testimony in March 2011 clearly indicate that dealing with AGW and reducing GHGs emissions is urgent and that prompt action must be taken. Why not? Not surprisingly, his personal position is quite a different view from the policy statement issued by the AGU on behalf of its almost 60,000 members from over 130 countries who are members of the AGU. That statement says very clearly:
    "If this 2°C warming is to be avoided, then our net annual emissions of CO2 must be reduced by more than 50 percent within this century."

    One last intriguing observation on Dr. Pielke's testimony. As someone with numerical modeling experience, I'm confused by Dr. Pielke's (who is a modeler) claim that "Models themselves are hypotheses", in his book "Mesoscale Meteorological Modeling" which is on my bookshelf here, he says on page 1 that "....it is necessary to understand the basic physical and mathematical foundations of the models...". Quite different from what he said in his testimony. He then says "There is no way to test hypotheses with the multi-decadal global climate model forecasts for decades from now as step 2, as a verification of the skill of these forecasts, is not possible until the decades pass." This leads me to conlcude that Dr. Pielke is of the opinion that models are nothing more than untestable hypotheses...it would be a great shame if he thinks that his life's work amounts to that.
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  42. Dr. Pielke assures us that land-use change is a "first- order" climate forcing. But nowhere, at least where I can find does he indicate the magnitude of this forcing in W m-2 (with error bars) or in terms of his preferred units, Joules. He appears to be stating a fact without providing a quantifier to justify his assertion.

    Some estimates of land-use change did appear in WG1 of TAR in 2001. They say:
    "Following Hansen et al. (1997b), Shine and Forster (1999) recommended in their review a value of -0.2 Wm-2 with at least a 0.2 Wm-2 uncertainty. We adopt those values here for the best estimate and range, respectively; however, in view of the small number of investigations and uncertainty in historical land cover changes, there is very low confidence in these values at present."

    Even if one takes the upper range, one is probably looking at <0.5 W m-2, quite small compared to the expected forcing from GHGs and tropospheric ozone, for example. Also, note the uncertainty-- hardly a given as suggested by Dr. Pielke.

    As evidence of the importance of land-use change on climate (he does not specify "global" or regional", but it is made in the context of "future behavior of Earth’s climate"), Dr. Pielke in his EOS essay cites Takata et al. (2009). However, that is a regional modeling study using an AGCM. So I sense a double standard by Dr. Pielke when it comes to the value of the AOGCMs. Maybe Dr. Pielke would like to comment on the paper by Sitch et al. (2005)?

    I and others have no doubt that land-use and land cover change can have marked local and even regional effects on weather and climate, but remain unconvinced that human land-use change is currently (or in the future will be) a first-order driver of global climate and TOA radiation imbalance. That may have been the case in the late 19th and early 20th centuries when the forcing from GHGs was much smaller. Dr. Pielke does not also seem to appreciate that changing climate in itself can also bring about land-use change as eco zones change.

    There is also an interesting self-contradiction in Dr. Pielke's logic when it comes to his argument about what he considers to be first-order climate forcings and how one monitors climate change, but I'll save that for later.

    And, contrary to claims made by Dr. Pielke, the role of land use is not being ignored or played down in the IPCC assessment reports. From AR4,
    "Understanding land-use and land-cover changes is crucial to understanding climate change. Even if land activities are not considered as subject to mitigation policy, the impact of land-use change on emissions, sequestration, and albedo plays an important role in radiative forcing and the carbon cycle."

    All for now.
    0 0
  43. The Games People Play ...

    I suspect Pielke is playing games here. Although I cannot speak on behalf of Sks on this post, I make the following observations.

    If a climate skeptic puts forward two alternative “framings” of the debate, neither should be given blanket endorsement. The best response would be for Sks to formulate its own preferred “framing” of the issues.

    It is likely that Pielke thinks he can entrap Sks, cherry-picking words or phrases in Sks’s response in an effort to discredit it, outside of the context of Sks’ well structured and comprehensive analysis of the evidence. Compare the alternative texts and spot the differences. I believe Sks should be prepared to do a phrase by phrase analysis, endorsing one or other option for each phrase (or neither) as appropriate. Consider the alternative texts in Pielke’s second question:

    Mike Hulme i: human greenhouse gas emissions
    Mike Hulme ii: human greenhouse gas emissions, land use changes and aerosol pollution

    The first is correct because the climate is driven by CO2. The major forcings are CO2, methane, etc. and their positive feedback through water vapour, as illustrated diagrammatically on the Sks site. However, the second wording might be seen as more comprehensive in that it specifically includes greenhouse gases and aldebo changes associated with agriculture as well as the negative forcing of aerosols. Therefore, in relation to this phrase alone, I agree with Dana in saying “the second framing is probably more appropriate, as addressing climate change will involve more than just CO2 emissions reductions”.

    Mike Hulme i: climate changes that cannot be explained by natural causes
    Mike Hulme ii: which exacerbate the changes and variability in climates brought about by natural causes.

    I think Pielke sees the first as a solid endorsement of AGW, while the second is a softer partial endorsement of AGW. For this phrase, would not SKs back the first?

    Mike Hulme i: we are causing it
    Mike Hulme ii: humans are contributing to climate change

    This is similar to the above example. The first as a solid endorsement of AGW, while the second is a softer partial endorsement of AGW. Again, would not SKs back the first?

    Mike Hulme i: it is happening right now
    Mike Hulme ii: it is happening now and in the future for a much more complex set of reasons than in previous human history

    The first as an emphatic statement that climate change is underway (as we are witnessing in the Arctic). The second is a softer statement, and seems to suggest a more uncertain trajectory for global warming because of “complexity”. Again, should not Sks reject this fudge language and back the first?

    Do you now see the trap? In the first option we encounter, I think Pielke entices the reader to endorse the second wording. He seeks to get a simple endorsement of “Mike Hulme ii”, in order to trap the reader (and potentially Sks) into endorsing by implication the second wording for the remaining options. As I have argued above, I think Sks would be much more likely to back the first phrase in these latter choices. Perhaps Dana should qualify his response to Pielke’s second question.

    The same phrase by phrase analysis should be applied to Pielke’s Hypothesis 2a and Hypothesis 2b, but I leave that as an exercise for the reader.

    Oh the games people play now
    Every night and every day now
    Never meaning what they say now
    Never saying what they mean …
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  44. Prof. Pielke, please could you comment on the paper by Douglass et al.

    Douglass D. H., Christy, J. R., Pearson, B. D. and Singer S. F., "A comparison of tropical temperature trends with model predictions", International Journal of Climatology, Volume 28, Issue 13, pages 1693–1701, 15 November 2008

    This paper purports to show that observed tropical trophospheric temperatures are inconsistent with model projections, however the statistical test they used is obviously flawed (it would reject the theoretically ideal model which had perfect physics, infinite temporal and spatial resolution and an infinite ensembe to give a perfect characterisation of internal climate variability).

    Do you agree that this paper is flawed and the conclusion not supported by the evidence?
    0 0
  45. I think I understand Prof Pielke's scientific desire to say things are alot more complicated than just CO2, and even just Greenhouse Gases.

    I agree land use changes, aerosols, black carbon, sulphates etc have important impacts.

    My main point, though, is that if coal, and other fossil fuels, were used less then many of these issues would be reduced.

    CO2 is being used as a proxy for Carbon, which is being used as a proxy for fossil fuels - which contain sulphates, emit aerosols, and cause carbon black.

    This is about framing - and reading the different statements I find the nuances interesting, but a bit too nit-picking, but hey this is a debate about science where details matter.

    But basically isn't the hypothesis:

    Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and increasing due to population growth and increased energy output with economic growth. Human influences are dominated by our use of fossil fuels causing the emissions into the atmosphere of both greenhouse gases, the most important of which is CO2, and aerosols. The adverse impact of the use of fossil fuels on regional and global climate, along with land use change from increasing population, constitutes the primary climate
    issue for the coming decades.


    This tries to cut away from the nit-picking science and goes to the basic causes - our economy is based on fossil fuels, our population is growing and increasing its use of these fuels and this is effecting the climate.
    0 0
  46. Having read this thread, and observed the efforts of Dr. Pielke to avoid addressing simple observations and interpretations with simple forthright statements (as opposed to creating the impression that our understanding and policy should be centred around nit-picking issues of semantics and sentence construction....

    ...I cannot recommend highly enough the short talk by Dr. Scott Denning at the recent Heartland Institute "Climate Science" meeting. Dr. Denning knows how to call a shovel a shovel, and cuts through exactly the sort of prevarication and nit-picking that is such a drain on productive discourse and policy making. Can't be recommended highly enough.
    0 0
  47. MODERATOR:

    - I get the impression that the steam has run out for Issues 1 & 2. Would you please formally announce that the topic is shifted to Issue 3: on preferred diagnostics for global warming?

    - I note that Dikran Marsupial's post at #44 seems relevant to the new topic.

    - Of course, if Dr. Pielke has more to say on 1 & 2, we can re-adjust.
    0 0
  48. I am very surprised to see a scientist even consider asking question number three. Why would you only look at a small subset of data, unless you are motivated by what you wish to find.
    0 0
  49. KR - You write

    "I have to strongly disagree (as I have before, on other venues) with your emphasis on regional effects over global effects."

    The weather that affects people is regional and local in scale. The global average tells us little, if anything, about weather patterns such as droughts, floods and so forth. It may be that a higher global average surface temperature is correlated with changes in frequencies in these extreme weather events; the models have not shown skill in such a prediction. Regardless, however, it is the changes in regional and local climate statistics that matter and that is where our focus should be.
    0 0
  50. Tom Curtis - I have framed two distinct testable scientific hypotheses. The relative importance of enhanced GHG forcing and ocean acidification (from added CO2) is certainly included. We will just have to disagree and move on, if you will not present two testable hypotheses of your own which we can discuss.
    0 0
    Moderator Response: [John Hartz] If this were a conference call, I would politely ask Dr. Pilke and Tom Curtis to continue this discussion off-line. Having said that, let's move the discourse to other topics that have not yet been addressed in any depth on this comment thread, e.g., the metrics for measuring climate change.

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