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Comments 72851 to 72900:

  1. Pielke Sr. and SkS Warming Estimates
    I think it's worth mentioning that while Pielke now says it doesn't matter whether CO2 is responsible for 25 or 50% of the net positive forcing, his own presentations say otherwise. In his 2006 presentation which we referenced in this post, Dr. Pielke devoted 4 slides to this issue. And on his blog, he has devoted several posts to the subject. And at the Conference on the Earth’s Radiative Energy Budget Related to SORCE on September 20-22, 2006, he made the same argument using the same presentation. The presentation has also been featured on several 'skeptic' blogs (i.e. Jennifer Marohasy and JunkScience). And just last month in an interview with a Canadian newspaper (and in our discussions here), Dr. Pielke argued that too much attention is being paid to CO2 - based on our calculations, that's a hard argument to justify. Suddenly claiming that the question is an unimportant one seems like a fairly radical and sudden change, given how frequently Dr. Pielke makes this argument. But as KR suggests, we will probably have to agree to disagree and move on.
  2. It's cooling
    And WoodForTree's own Temperature Index ("...the mean of HADCRUT3VGL, GISTEMP, RSS and UAH, offset by their baseline differences...") also seems to show a positive trend. Any thoughts, NETDR ?
  3. Pielke Sr. and SkS Warming Estimates
    Dr. Pielke: "the radiative forcing requires a baseline year." is not correct. The quote you have states "ΔF is the change in forcing". That does require a base year. The forcing does not and is instantaneous. I will point out that, despite this side-track of current forcing imbalance, the original topic of this thread and the tables that are the basis of the discussion are the numbers for changes in forcing since 1750, as is customary in this field. That is, incidentally, completely clear from the TAR through AR4, as defined in the glossaries, and in labeling of the various tables. In that regard you have repeatedly emphasized a 26.5% relative contribution by CO2 to the forcing deltas, in disagreement with IPCC estimates (here, for example), stating that "The IPCC Has Provided An Inaccurate Narrow Perspective Of The Role Of Humans". At this point in the discussion I believe that dana and Tom Curtis have clearly presented why they disagree. In my opinion you have neither presented either a relevant argument for your factor of ~2x difference with IPCC numbers on total forcing, nor for that matter any numeric estimates of yours as to "CO2 ... warming of average global surface temperature over the past century". Perhaps an agreement to disagree on this topic?
  4. It's cooling
    NETDR wrote : "The reason that we have failed to warm since 2001 is that the ocean currents [PDO] have turned negative and we will have more La Nina's than El Nino's for 20 to 30 more years." Trying to ignore your cherry-pick of HadCrut data (and noting that two out of the four datasets show positive trends, i.e. warming), what do you base your prediction of "20 to 30 more years" on ? By the way, although I haven't analysed the data, the Japanese Meteorological Agency's dataset seems to show a positive trend since 2001 too. Any thoughts ?
  5. It's cooling
    164, NETDR, Nicely cherry-picked year. Well done. And naturally ending in a La Nina. Also well done. Here's the raw data, with your trends (for all data sources).
  6. It's cooling
    CB I entirely agree. There is a 1/2 ° C warming trend superimposed on a 60 year sine wave from ocean currents, but we cannot discuss this on this thread it is contrary to the "let the wookie appear to win policy"! The reason that we have failed to warm since 2001 is that the ocean currents [PDO] have turned negative and we will have more La Nina's than El Nino's for 20 to 30 more years. http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml Notice that since 2000 the El Nino's have about balanced the La Nina's and it has warmed in the former and cooled in the latter. 2011 is a la Nina year and 2012 is predicted to be one too so it will be cooler probably for many years. The slow warming is of interest only to climatologists and in no way is a problem for mankind. (-Snip-).
    Response:

    [DB]  Your sudden, laser focus on short, statistically insignificant timescales is rather puzzling, given your earlier comment:

     

    Quibbling about whether it warmed or cooled during the last 12 years is pointless.

     

    Repetitive complaints about moderation snipped. 

    Unsupported summary musings (i.e., handwavings) struck out.  Please stick to the science, please.

  7. It's cooling
    Netdr: "we have failed to warm since 2001" No the wookie doesn't win because the wookie's base premise is incorrect: 2010 tied for Warmest Year on Record. Although since you like to cherry pick, here's 2011's hottest summer on record.
  8. It's cooling
    164, NETDR,
    There is a 1/2 ° C warming trend superimposed on a 60 year sine wave from ocean currents...
    Citation of peer reviewed evidence of this, please.
    The reason that we have failed to warm since 2001 is that...
    Citation of peer reviewed evidence of this, please. And not just that we're going to have more La Nina's, but rather evidence that this is going to affect the long term global mean temperature.
    ... the El Nino's have about balanced the La Nina's and it has warmed in the former and cooled in the latter.
    Yes, pretty much as they always have. Is there a point in this, other than to imply without evidence or logic that ENSO itself causes warming or cooling?
    ...it will be cooler probably for many years.
    Citation of peer reviewed evidence of this, please.
    The slow warming is ... in no way is a problem for mankind.
    You don't understand the science. Please read Spencer Weart's The Discovery of Global Warming. Then come back here and go step by step through this site, like a true skeptic, trying to refute your own beliefs/arguments, and see what you discover. Hint: The globe has not been cooling. You might try actually reading the post on which you are commenting.
  9. It's cooling
    NETDR wrote : "There has been no warming of the atmosphere since 2001. http://www.woodfortrees.org/plot/hadcrut3vgl/from:2001/plot/hadcrut3vgl/from:2001/trend" Why not use all four temperature data sources ? There, you will find that the two smallest trends (which are negative) are HadCrut and RSS, while the larger (positive) trends are GISS and UAH. Why do you prefer the HadCrut figures ?
  10. Pielke Sr. and SkS Warming Estimates
    Dr. Pielke writes: >>The question is hardly "hypothetical" as the water vapor/CO2 overlap is a scientific issue. So is the matter of radiative forcing. Yet, you write "For example, why does it matter if the fraction of radiative forcing in 2005 compared with pre-industrial was 28% or 48%?" That strikes me not only as anti-scientific, but hypocritical. You imply that the Mhyre paper does not adequately address the overlap issue, but you are not at all specific, instead relying on a hypothetical question and to your own blog post (as opposed to a peer reviewed article) to provide some refutation, though even then, you remain vague as to how this overlap supports your original estimate of 28%.
  11. Greenland ice loss continues to accelerate
    A separate data set is the laser altimetry data set, that revealed mass losses of 191 to 240 gigatons/year (Soresnon et al ,2011) for the 2003-2008 period.
  12. Pielke Sr. and SkS Warming Estimates
    Tom Curtis wrote: >>If you cannot debate under the condition that your mistakes will be corrected, then (speaking only for myself), I see little point in debating you. Keep in mind you are not trying to convince Dr. Pielke, but convince the audience at SkS, so I would encourage you to keep posting, as your posts have proved very valuable and instructive.
  13. Pielke Sr. and SkS Warming Estimates
    dana1981 - You also write "Because the question is purely hypothetical, it is irrelevant to future discussions so I have no interest in doing a literature search in the off chance that somebody has answered this hypothetical." The question is hardly "hypothetical" as the water vapor/CO2 overlap is a scientific issue.
  14. Pielke Sr. and SkS Warming Estimates
    dana1981 "the radiative forcing requires a baseline year." is not correct. The quote you have states "ΔF is the change in forcing". That does require a base year. The forcing does not and is instantaneous. One would never state that "acceleration requires a base time period." Acceleration is the derivative of the velocity at any time. Similarly, radiative forcing is at a specific time although one could time average (e.g. the yearly global averaged radiative forcing).
  15. It's cooling
    CB (-Snip-)! The reason that we have failed to warm since 2001 is that the ocean currents [PDO] have turned negative and we will have more La Nina's than El Nino's for 20 to 30 more years. http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml Notice that since 2000 the El Nino's have about balanced the La Nina's and it has warmed in the former and cooled in the latter. 2011 is a la Nina year and 2012 is predicted to be one too so it will be cooler probably for many years. The slow warming is of interest only to climatologists and in no way is a problem for mankind. (-Snip-).
    Response:

    [DB] "The slow warming is of interest only to climatologists and in no way is  a problem for mankind."

    Unsupported, and off-topic, handwaving.  See the "It's not Bad" thread.

    Moderation complaints snipped.

  16. Understanding climate denial
    Albatross, Actually, I know why the argument is occurring in general; supporters wanted to show that a vast majority agrees with them, while thedetractors wanted to show that a significant minority exists. The argument is immaterial. The subject is not up to a vote, therefore, numbers are irrelevant. For the record, I do not believe that a large range of values (whether it be climate sensitivity, projected warming, etc.) indicates that there is a consensus on the issue. On the contrary, it argues the opposite.
    Moderator Response: [Albatross] "Skeptics" claim that their is no consensus, so when consensus (or better yet, consilience) is demonstrated, they then claim that "science is not done by popular vote" or something along those lines, and of course it is not, so they are really arguing a strawman. Remember it is the "skeptics" who are appealing to popularity when they arrange petitions such as the Oregon petition. More here.
  17. Pielke Sr. and SkS Warming Estimates
    Very well Dr. Pielke. You may not agree with our corrections of your errors, but as I said, readers can decide for themselves who is right on this matter, since we have thoroughly documented the sources of our calculation and corrections in the post above. Regarding your question about the "current (2011) radiative forcing", I refer you to Tom Curtis' comment #37 (emphasis added):
    "ΔF = αln(C/Co), where ΔF is the change in forcing, C is the CO2 concentration in the current year, Co is the CO2 concentration in the inital year, and α = 5.35 (source; also Myhre et al, 98, and various IPCC reports). This is the simple formula referred to in AR4. Clearly from its formula, the radiative forcing requires a baseline year. It is impossible to derive the radiative forcing from this formula for a single year simpliciter for the result would necessarily be 0."
    If you would like us to answer your question, you will have to provide a baseline reference year. I also agree with Tom's answer to your first question, also in comment #37:
    "Because the question is purely hypothetical, it is irrelevant to future discussions so I have no interest in doing a literature search in the off chance that somebody has answered this hypothetical."
  18. Pielke Sr. and SkS Warming Estimates
    Tom Curtis 1) You write "A LBL (Line By Line) model as used by Myhre et al, 98, and Myhre and Stordal, 97 is a one dimensional radiative transfer model, and hence the papers to which I have been referring answer the general point you have been making" I agree they addrees the "general point". It is my specific question that an answer is needed for "What would be the global annual average radiative forcing change since pre-industrial with CO2 without the water vapor overlap and with the the overlap?" I doubt you could find it in a literature search because to my knowledge, it has not been done. That is why we did an estimate in Relative Roles of CO2 and Water Vapor in Radiative Forcing. http://pielkeclimatesci.wordpress.com/2006/05/05/co2h2o/ Further Analysis Of Radiative Forcing By Norm Woods http://pielkeclimatesci.wordpress.com/2007/08/24/further-analysis-of-radiatve-forcing-by-norm-woods/ 2) Regarding "forcing", the NRC (2005) - http://www.nap.edu/openbook/0309095069/html/ writes "Climate forcings can be classified as radiative (direct or indirect) or nonradiative. Direct radiative forcings affect the radiative budget of the Earth directly; for example, added CO2 absorbs and emits infrared (IR) radiation. Indirect radiative forcings ..." "Climate forcings can be classified as radiative (direct or indirect) or nonradiative. Direct radiative forcings affect the radiative budget of the Earth directly; for example, added CO2 absorbs and emits infrared (IR) radiation. Indirect radiative forcings create a radiative imbalance by first altering climate system components, which then almost immediately lead to changes in radiative fluxes; an example is the effect of aerosols on the precipitation efficiency of clouds." This usage conflicts with your statements. In fact, you are inappropriate mixing a "forcing" from a "change in forcing over some time period". A forcing (such as produces an acceleration, is immediate). 3) Finally, I quess you and I are done. You are so utterly (dogmatically) convinced of your viewpoint, you are not interested in a contstructive debate. You claim to have shown I am wrong (my "gross errors) on a trivial issue, yet refuse to adequately answered a set of more substantive questions I have presented. You are not debating; you are lecturing.
  19. Pielke Sr. and SkS Warming Estimates
    dana1981 I never said I agreed with all your "corrections" (and you have even used my back-of-the-envelope estimate with solar included). You call them "errors" which hardly represents my view of the estimates. I just "accepted" them and then started with the higher fraction of positive radiative forcing from CO2 and presented other reasons it should be lower. From IPCC AR4 to Skeie 2011 it has been reduced from 52.4% to 48.2% [quite a bit of significance with three significant digits for such an imprecise quantity]. To also refer to the Myhre paper as the definitive statement ("seminal") is quite an overreach. The water vapor/CO2 overlap has not been completely addressed and I have repeated my question and will do so again; What would be the global annual average radiative forcing change since pre-industrial with CO2 without the water vapor overlap and with the the overlap? I also repeat What is the current (2011) radiative forcing from each of the terms (including CO2) and what is the current radiative imbalance? Let us see your back-of-the-envelope estimate for these.
  20. It's cooling
    NETDR, yes we've seen cherry picking before. Let's look at this a bit more broadly, shall we? Start year Trend 1850 - 2000 Positive 2001 - 2005 Negative 2006 - 2008 Positive 2009 - 2010 Negative So... you can find a negative trend from seven of the past 161 years to present. None of which shows a statistically significant trend, because they were all within the past decade. There have been much more pronounced 'cooling' trends in past decades despite rising CO2 levels. There is nothing at all surprising about that or the current downturn... because CO2 is not the only thing which impacts atmospheric temperatures.
  21. Pielke Sr. and SkS Warming Estimates
    JMurphy - I am able to present my viewpoint on my weblog. Colleagues (even those who disagree with me) reply via e-mail and I have posted a number of guest posts from such an interaction. As shown here, however, (and when I had comments), people often see they have an opportunity to become personal.
  22. It's cooling
    Perhaps someone can give me information. There has been no warming of the atmosphere since 2001. http://www.woodfortrees.org/plot/hadcrut3vgl/from:2001/plot/hadcrut3vgl/from:2001/trend Since there has been millions of tons of CO2 emitted why is that ? The models say that there is a warming offset by aerosols causing no overall warming. To get the warming desired the aerosols are projected to disappear and the temperature climb. [Does that about cover it ?] Does anyone have a link to a graph of aerosol emissions ? Does anyone have a way of determining how much a ton of aerosols affects the temperature of earth ? [Or does each modeler tweak the values to suit his model sensitivity ?] Or has the argument shifted to "the heat is being radiated out to space" or hidden in the oceans below the top 700 M ? [anywhere that it isn't causing much if any warming ?]
    Response:

    [DB] Please separate these questions into individual comments placed on more appropriate threads; as constructed this comment amounts to a Gish Gallop & thus needs no refuting.  Thanks!

  23. Greenland ice loss continues to accelerate
    fydijkstra I guess you didn't notice mspelto's comment, to which I add that sea level depends on many factors other than Greenland loosing mass. I'm sure you realize this.
  24. Greenland ice loss continues to accelerate
    This is an interesting contradictory topic. The ice loss of the ice cap is accelerating, we are being told every year. Nevertheless the sea level rise does not accelerate, but slows down. I think that we should realise that Grace does not measure ice mass, but only gravitation. If there are other changes in the earth crust that change the gravitation significantly (such as the ever more continuing rise of the land after the melting of the ice caps at the end of the last ice age), the Grace data are not reliable to monitor the volume of the present ice cap. See Wu et al, Nature Geoscience 3, 642 - 646 (2010).
    Response:

    [DB] "The ice loss of the ice cap is accelerating, we are being told every year."

    You refer to the ongoing loss of the Arctic Sea Ice cap, which is indeed ongoing, but floating (and thus adds nothing to the sea level budget).

    The GIS is indeed losing mass, in a greater-than-linear fashion.  The ongoing SLR is indeed ongoing, when measured at periods long enough to be considered staitically significant.  See one of the many threads here on that subject.

  25. Understanding climate denial
    Jonathon, "but do not know why a consensus argument is occurring on sites like this. " Actually I think that you do. But in case you really do not recall, it is to address a meme started by "skeptics". I'll provide a link soon to clarify.
  26. Understanding climate denial
    211, Jonathan (ETR), Hmph. Do not play dumb. Words to live by, eh? Okay, let us try again. You intimated that the problem is that people are too simplistic in how they see the debate, and that maybe there is a consensus on whether there is warming, but no consensus on the cause or effects. Your analysis is also grossly flawed, because the consensus of current science covers not only the warming, but also the cause and effects, so even if your premise were correct, your conclusion is still wrong. Next, you threw out the red herring that the blogosphere tries to simplify the issue, but you're sage enough to see through it. That is far from the case. The blogosphere is full of every argument imaginable, trying anything at all to see if it sticks, and the one where they have the greatest chance at traction and so have been hammering it to death is in fact that of climate sensitivity. Your observation completely fails in this regard. You finish by claiming that you don't know why there is an argument about the consensus, and then have the gall to intimate that such an argument only exists on this web site (or sites "like" it)! I'll give you a hint... when I asked it, it was a rhetorical question. The argument about the consensus exists on this issue, in this day and age, because there is a well funded denial machine, and a legion of foolish deniers, who will grasp at any straw they can to try to make it appear that the science is not thorough, and one of those flimsy straws is the consensus argument. Don't play dumb, Jonathan-The-Red, and do not bandy words in an effort to make the denial position look remotely credible. I'll say it again... you need to figure out what sort of irrational behaviors deniers exhibit over and over again (read the post above!!!!), look in the mirror, and recognize which of them applies to you in spades.
    Moderator Response: [Albatross] Can you and Jonathon both please tone down the rhetoric. Thanks.
  27. Understanding climate denial
    Sphaerica, Do not play dumb. It is insulting to both of us. I explicitly removed blogs and focused on scientific papers when formulating a response to your questions, and you then proceeded to include blogs in your followup. I see the difference. You seem to deny that which does not fit your own set of beliefs. BTW, I answered two of your three questions, but do not know why a consensus argument is occurring on sites like this.
  28. Pielke Sr. and SkS Warming Estimates
    Dr Pielke @34, 1) A LBL (Line By Line) model as used by Myhre et al, 98, and Myhre and Stordal, 97 is a one dimensional radiative transfer model, and hence the papers to which I have been referring answer the general point you have been making. They, however, address the practical question of what the radiative forcing is in the real world which includes water vapour. They do not adress the hypothetical question that you ask, ie, what would the radiative forcing of CO2 be in the absence of water vapour. Because the question is purely hypothetical, it is irrelevant to future discussions so I have no interest in doing a literature search in the off chance that somebody has answered this hypothetical. Please note that the radiative forcing of CO2 if there was no overlap with H2O, and the radiative forcing of CO2 in the absence of water vapour are the same, so the slightly different form in which I have expressed the question is of no consequence. The global annual average radiative forcing of CO2 in the presence of H2O with overlaps accounted for in 2005 is the value given by the IPCC in AR4. The value in 2011 is that given by Skeie et al. 2) From the glossary of IPCC AR4:
    "Radiative forcing Radiative forcing is the change in the net, downward minus upward, irradiance (expressed in W m–2) at the tropopause due to a change in an external driver of climate change, such as, for example, a change in the concentration of carbon dioxide or the output of the Sun. Radiative forcing is computed with all tropospheric properties held fixed at their unperturbed values, and after allowing for stratospheric temperatures, if perturbed, to readjust to radiative-dynamical equilibrium. Radiative forcing is called instantaneous if no change in stratospheric temperature is accounted for. For the purposes of this report, radiative forcing is further defined as the change relative to the year 1750 and, unless otherwise noted, refers to a global and annual average value. Radiative forcing is not to be confused with cloud radiative forcing, a similar terminology for describing an unrelated measure of the impact of clouds on the irradiance at the top of the atmosphere.
    (My emphasis) Therefore, according to the glossary, when the IPCC AR4 refers to the radiative forcing for 2005 they mean the change in radiative forcing in 2005 relative to 1750, unless they explicitly state otherwise. That could not be clearer. What is more, the formula for radiative forcing of CO2 is given by the simple formula: ΔF = αln(C/Co), where ΔF is the change in forcing, C is the CO2 concentration in the current year, Co is the CO2 concentration in the inital year, and α = 5.35 (source; also Myhre et al, 98, and various IPCC reports). This is the simple formula referred to in AR4. Clearly from its formula, the radiative forcing requires a baseline year. It is impossible to derive the radiative forcing from this formula for a single year simpliciter for the result would necessarily be 0. Consequently no interpretation of "Radiative Forcing" in AR4 in which it is treated as being the forcing in a single year is consistent with the text which explicitly refers to this simple formula. In other words, not only are you in error in your interpretation of the IPCC AR4, logically your interpretation could not have failed to be in error. Note I say that you are in error because you insist on interpreting the IPCC AR4 as inconsistent whereas in fact you are simply failing to interpret their words in accordance with the glossary. 3) You object to what you call my snark. Well I object to the extreme lengths of misrepresentation you are prepared to go to cover up an error. Please note that "misrepresentation" is neither snark nor accusation. It simply notes that you have represented the facts to be one way (the IPCC AR4 was corrected; the IPCC AR4 is inconsistent) when transparently, and as could be discovered by simply reading a glossary, they were another way. You and I are both here trying to reach SkS's audience in order to convince them of what we believe to be the truth about global warming. Fine, I am a great believer in the open market of ideas. But I will not accept a restraint on me that I must not correct your gross errors should they occur (and as has occurred) because such correction will offend our sensibilities. If you cannot debate under the condition that your mistakes will be corrected, then (speaking only for myself), I see little point in debating you.
  29. Greenland ice loss continues to accelerate
    7 Arkadiusz, that's a good point and it's great news. It seems the likelihood of getting multi-metre sea level rise from subglacial lubrication is pretty low, although Professor Shepherd has always made it very clear that these results need to be included in a complete model before you can constrain what this really means in terms of melt amounts. If you read the paper or look up one of his presentations you'll see that the effect was only noted in glaciers with big catchments. Smaller outlets (and glaciers in currently cooler areas) have not experienced the initial speed up yet, but if warming continues then there's a chance that there would be enough meltwater to trigger a speedup but perhaps not the efficient drainage. This effect might be tiny, but I get the impression it needs more work to quantify. Also, the work by Rahmstorf et al on the link between sea level rise and temperature suggests that the IPCC projections are probably on the low side. Maybe the relationship no longer holds, but if it does then current models are missing something to do with ice loss. That would also explain why sea levels are rising on the high end of IPCC projections.
  30. Pielke Sr. and SkS Disagreements and Open Questions
    Let's move on to point #2. 2) Regardless of your reason for choosing 1998 as the starting point for your analysis, our explanation regarding why it was a poor choice remain valid. 1998 was a statistical outlier in the TLT record, and thus is a poor choice for a starting point when estimating a trend, especially since we also know that 13 years is an insufficient timeframe according to the very study you were critiquing (Santer et al. 2011):
    "Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature."
    The starting point makes a big difference in the trend for such short timeframes. The UAH trend is 0.10°C per decade since 1997, 0.06°C per decade since 1998, 0.18°C per decade since 1999, and 0.14°C over the past 17 years. Note that changing the starting date by a single year from 1998 to 1999 triples the UAH TLT trend.
  31. Pielke Sr. and SkS Warming Estimates
    Dr. Pielke, you made a rather odd statement:
    "The values I present were given to show reasonable deductions from the IPCC value and that of Skeie 2011. I do not know the precise value (and neither does anyone) but the fraction is clearly well less than 50% using reasonable values."
    Let's examine where we're at in this discussion. You originally argued that CO2 was only responsible for 26-28% of the net positive radiative forcing. We found some mathematical errors in your calculations which bring the value up to ~30%, and you concur with these corrections. We also identified a 0.3 W/m2 error in your methane estimate, a 0.5 W/m2 error in your albedo estimate, a 0.3 W/m2 error in your ozone estimate, and a 0.4 W/m2 error in your CO2 estimate - you appear to concur with all of these corrections, with some caveats on CO2. These corrections bring the value up around our original estimate of 50%. You then claimed that 20% of the CO2 forcing has been "accomodated by a warmer climate" based on a personal communication. We have several issues with this claim, but regardless, it is not relevant to the question at hand (the CO2 contribution over the past century). Your only other revisions to the Skeie estimate are to use the Ramanathan and Carmichael best estimate for the black carbon forcing of 0.9 W/m2 (without justification for this choice, which also conflicts with your previous claim that the black carbon forcing is 0.5 W/m2), an assertion of a 0.2 W/m2 aerosol forcing, and an assertion that the water/CO2 overlap in the tropics has been ignored. As Tom Curtis has noted, the overlap was addressed in seminal work by Myhre, and incorporated into the IPCC reports. There is reason to believe the Ramanathan BC forcing is too high (i.e. see Bond 2011 and another paper by Skeie et al. 2011), but incorporating their BC value and your aerosol forcing estimates, the CO2 contribution is still between 41% and 50%, and certainly far greater than your originally asserted 26%. So we can emphasize the point that any reasonable calculation based on the agreed-upon inputs will put the CO2 contribution to the net positive forcing at 41% to 50% and rising. You now claim that whether the value is 25% or 50% does not matter, yet you have frequently raised the issue on your blog and in presentations and talks. Ultimately we have identified a number of errors in your calculations, and yet you continue to insist that despite these corrections, somehow your argument must be correct. We have supported our estimate with detailed calculations and references, and have demonstrated that CO2 has thus far accounted for approximately 0.8C surface warming - a calculation which you have not disputed. We are a bit disappointed that this refutation of your reasoning leaves your sense of conviction so unmoved, but at this point, we may as well move on to other issues. Readers can examine our calculations for themselves and decide who is correct.
  32. Pielke Sr. and SkS Warming Estimates
    But when you start with insults because I do not accept your view, I will go off to where more constructive debating occurs. As a matter of interest (and certainly not in a snarky or insulting manner), can you give any examples of where you would get such debating - if you have online sources in mind ? I am genuinely interested.
  33. Pielke Sr. and SkS Warming Estimates
    Tom Curtis - You seem to persist in missing my issue. I know the models have been applied which include the water vpaor and CO2 overlap. However, I have not seen this reported using the 1-D radiative transfer calculations as I proposed. I repeat my question (and stop referring to papers - I am asking a straightforward question): What would be the global annual average radiative forcing change since pre-industrial with CO2 without the water vapor overlap and with the the overlap? On the IPCC values, I agree that they are presenting the difference between pre-industrial and 2005. That is not in dispute. They are inconsistent, however, in terms of how they write this in the text in places as they specifically write, for example, in SPM.2 "Global average radiative forcing (RF) estimates and ranges in 2005" [http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf] This is a trivial issue, except that i) the statement is incorrect as it is not the "forcing" in 2005 and ii) quite a few people accept that the values in the figure are the current forcings. Finally, if I am going to continue this discussion with you, keep your snarky comments out of your posts. That is why I left SkS before. We disagree. That's the way science goes. But when you start with insults because I do not accept your view, I will go off to where more constructive debating occurs.
  34. Philippe Chantreau at 02:35 AM on 12 October 2011
    Understanding climate denial
    Elsa, one thing puzzles me. Why are you not more skeptical of the opinions and statements you have thrown in the conversation so far? Even a small amount of cursory search would easily have shown what has been summarized above by other contributors. Why did you not discover that information on your own?
  35. Understanding climate denial
    "All things considered, alarmism seems like common sense to me." Source: “The Case for Climate-Change Alarmism”, Op-ed by William Pentland, Forbes, Oct 10, 2011 To access this informative opinion piece, click here
  36. Understanding climate denial
    196, Jonathan (ETR),
    You asked two questions, and yes, this is not the thread to get into a lengthy discussion about such.
    Yes, I did. You then proceeded to discuss other questions, not the ones I asked, which were:
    So why do you think there is this consensus argument now? ... is there a consensus?
    Now, if your response was meant to (in a round about way) answer these questions by claiming that there is no consensus on the points you highlighted... you are wrong, plain and simple, and you are seeing what you want to see by giving inordinate weight to a small number of denialists that primarily put their message out not through studies but through interviews and blog posts. Do you see the differences here? Do you see how you are yourself in desperate need of reading, understanding and digesting the post in question -- understanding your own denial?
  37. Understanding climate denial
    Elsa, You have not been listening to what people said here about the significance of consensus. Of course it is not part of any decision making process in science. It is an outcome of such processes. If the science has settled down and there are explanations that nearly all scientists working in the field accept then there will be a consensus. As others have said consensus has only been mentioned because a rebuttal of claims that the science is disputed was necessary. Saying there is a consensus among those working in a field is another way of saying claims of the science being disputed among those working in that field are false. How do scientists know if they have got it right? What they rely on is the consilience of evidence. That is, since the Universe runs under a consistent set of natural laws, if a hypothesis is correct then there will be multiple types of observations that are consistent with it. Scientists do not really trust single proofs. There is almost allways an alternative explanation, often a contrived one, for any single piece of evidence. They want lots of different proofs. They want there to be so many types of supporting evidence that to believe that they are all wrong strains credulity. In such a case it becomes difficult to justify alternative explanations. We have reached that stage in climate science. While the exact value of the sensitivity to CO2 is not known, we do know in what range it is. And that range is high enough to cause us serious problems.
  38. Understanding climate denial
    191, elsa, You said:
    We are not given the information by physics that we could then test. What we have is information obtained by measurements about temperature and CO2 which we then fit together in a model.
    This is not the place to discuss it, but this statement is 100% false. Your understanding of how the modeling is done is grossly flawed. You should educate yourself more before speaking on the topic, or making any decisions about your own beliefs in credibility of the current position of climate scientists. Climate models emulate the physics and the physics alone. They do not work from simple correlation. When the physical model "coincidentally" parallels real world observations well, the scientists know they got the physics (and the model) right. Aside from this site (type "models" into the search box), RealClimate has an excellent synopsis of modeling you might want to look at: RealClimate FAQ on climate models RealClimate FAQ on climate models Part II I also always recommend that anyone and everyone read Spencer Weart's The Discovery of Global Warming.
  39. Greenland ice loss continues to accelerate
    Kevin(14): And coincidentally, 6mm is about the amount of the drop in sea level over the last 12 to 18 months due to increased rains over land and subsequent flooding. So we've effectively seen that huge amount of water move from ice in Greenland to water on land in various other places in roughly a decade. (Just to be clear, I am NOT drawing any other conclusions or implying anything by pointing this out. I think it's merely an interesting coincidence that helps highlight the complexity and interconnectedness of the environment.)
  40. Dikran Marsupial at 01:49 AM on 12 October 2011
    Models are unreliable
    chuidburg The answer is yes and no. We do have enough computer power to run the simulations that demonstrate quite unequivocally that anthropogenic climate change is real and that natural forcings are unable to explain much of the observed warming. However, our characterisation of the uncertainties involved will continue to improve the more experiments we perform. So whether you think there has been enough depends on where you put the goalposts (which your friends has been extremly vague about). I suggest you challenge your friend to read chapters 8 and 9 of the most recent IPCC WG1 report and make a specific suggestion of an experiment that they haven't pursued, that relates to a scenario or theory that is plausible and has some support from observational evidence. Ask him to specify exactly what simulations would need to be run to perform the ANOVA to his satisfaction (an ANOVA is not the right tool anyway, as correlation is not causation, but that is another matter).
  41. Understanding climate denial
    Following on from CBDunkerson, I think the International Agency for Research on Cancer would also be surprised to hear that they aren't a UN group looking at peer-reviewed publications. In fact, they obviously don't state : IARC's mission is to coordinate and conduct research on the causes of human cancer, the mechanisms of carcinogenesis, and to develop scientific strategies for cancer prevention and control. The Agency is involved in both epidemiological and laboratory research and disseminates scientific information through publications, meetings, courses, and fellowships.
  42. Pielke Sr. and SkS Warming Estimates
    Dr Pielke @28, 1) I recommend that you reread my post @25, or better yet, Myhre and Stordal, 1997. As clearly indicated in my post, it was Myhre et al, 1998 who determined the strength of the CO2 radiative forcing by determining the value of the constant in the simple formula for radiative forcing. In doing so they corrected downwards the factor previously used from 6.3 to 5.35. As explained previously, Myrhe et al is built on the detailed model comparisons in Myrhe and Stordal 97, which include a global model run at a 2.5o x 2.5o resolution. That model, because global necessarily included the difference in radiative transfer between tropical and not tropical regions. To further clarify the point, I noted that M&S97 had also run both the broadband model and the LBL model for both tropical and mid-latitude summer conditions, with the latter showing the stronger forcing, clearly showing the effect of increased humidity and cloud cover had been included. To that information, we can add the following quote from the Third Assessment Report:
    "IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included. The lower forcing in the cited newer studies is due to an accounting of the stratospheric temperature adjustment which was not properly taken into account in the simplified expression used in IPCC (1990) and the SAR (Myhre et al., 1998b). In Myhre et al. (1998b) and Jain et al. (2000), the short-wave forcing due to CO2 is also included, an effect not taken into account in the SAR. The short-wave effect results in a negative forcing contribution for the surface-troposphere system owing to the extra absorption due to CO2 in the stratosphere; however, this effect is relatively small compared to the total radiative forcing (< 5%)."
    (My emphasis) The Fourth Assessment Report contented itself with saying:
    "The simple formulae for RF of the LLGHG quoted in Ramaswamy et al. (2001) are still valid. These formulae are based on global RF calculations where clouds, stratospheric adjustment and solar absorption are included, and give an RF of +3.7 W m–2 for a doubling in the CO2 mixing ratio. (The formula used for the CO2 RF calculation in this chapter is the IPCC (1990) expression as revised in the TAR. Note that for CO2, RF increases logarithmically with mixing ratio.) Collins et al. (2006) performed a comparison of five detailed line-by-line models and 20 GCM radiation schemes. The spread of line-by-line model results were consistent with the ±10% uncertainty estimate for the LLGHG RFs adopted in Ramaswamy et al. (2001) and a similar ±10% for the 90% confidence interval is adopted here. However, it is also important to note that these relatively small uncertainties are not always achievable when incorporating the LLGHG forcings into GCMs. For example, both Collins et al. (2006) and Forster and Taylor (2006) found that GCM radiation schemes could have inaccuracies of around 20% in their total LLGHG RF (see also Sections 2.3.2 and 10.2)."
    (My emphasis) Ramaswamy et al, 2001 is of course, the IPCC TAR. The IPCC do not feel it necessary to spell out details that have been public knowledge for six years (as at the time of the AR4), contenting themselves with a reference to the original discussion. Now, given the detailed analysis by Myhre and Stordal and the explicit statement by the TAR, do you still wish to maintain that the radiative forcing as calculated does not allow for overlap with H2O in the tropics? 2) The passage you quoted, it was not a figure caption, did not say otherwise, it just did not specify a fact that was well known. Further, the FAQ plus Fig 2 of the FAQ which I reproduced was not added afterwards. It can be found on page 135 of the PDF reproduction of the original report for anybody interested. What is more, the figure 2.20A on which it is based (page 203) has the same heading. And if that is not enough, we read in the executive summary of Chapter 2:
    "The combined anthropogenic RF is estimated to be +1.6 [–1.0, +0.8][2] W m–2, indicating that, since 1750, it is extremely likely[3] that humans have exerted a substantial warming influence on climate. This RF estimate is likely to be at least five times greater than that due to solar irradiance changes. For the period 1950 to 2005, it is exceptionally unlikely that the combined natural RF (solar irradiance plus volcanic aerosol) has had a warming influence comparable to that of the combined anthropogenic RF."
    (My emphasis) Seeing you bring up the Summary for Policy Makers, we read there:
    "Changes in the atmospheric abundance of greenhouse gases and aerosols, in solar radiation and in land surface properties alter the energy balance of the climate system. These changes are expressed in terms of radiative forcing,[2] which is used to compare how a range of human and natural factors drive warming or cooling influences on global climate. Since the TAR, new observations and related modelling of greenhouse gases, solar activity, land surface properties and some aspects of aerosols have led to improvements in the quantitative estimates of radiative forcing."
    You will notice the footnote after the introduction of the term "Radiative Forcing". That footnote reads:
    "Radiative forcing is a measure of the influence that a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. Positive forcing tends to warm the surface while negative forcing tends to cool it. In this report, radiative forcing values are for 2005 relative to pre-industrial conditions defined at 1750 and are expressed in watts per square metre (W m–2). See Glossary and Section 2.2 for further details."
    Should we check the glossary as well, or is my point sufficiently made? This is a very minor, an absolutely trivial point, except for one factor. It is one thing for a Professor of Climatology with, I must add, a very distinguished career, to make a simple mistake on a fact you would expect him to know well. It is quite another to try and save face by making "facts" up. Knowledge is not so often found in this world that it can be thrown away in face saving excercises.
  43. Understanding climate denial
    Tristan, also see the Interactive history.
  44. Understanding climate denial
    Hurrah! Thanks very much DSL
  45. Understanding climate denial
    Tristan, you need to meet The Denominator
  46. Understanding climate denial
    I'm trying to find the page on this site that compares the number of publications that don't agree with the IPCC's findings with the number of publications that do. I want to provide some context for those who state '900 skeptic papers can't be wrong'
  47. Understanding climate denial
    elsa, [snip] "I think my main point was that the situation of global warming is quite different from that of smoking or AIDS. There is proper science to back those areas whereas the science is lacking for AGW." This continues to be pure fiction. This site is full of proof to the contrary. Indeed, the science behind AGW is more firmly established than the 'how' of smoking induced cancer. "We do not appoint an equivalent of the IPCC for any other area" Really? The UN does not have a group dedicated to AIDS research? How strange. Does it never bother you that so much of what you write is obviously false? "Underlying this article is a belief that the writer is correct and that anyone who disagrees must be suffering from some sort of delusion or at best be hopelessly ill informed." See above about false statements. What other conclusions are we to draw?
    Moderator Response: [Dikran Marsupial] Moderation issue dealt with, so response snipped.
  48. Understanding climate denial
    Elsa, your description is incorrect. We've known the physical basis for AGW for 150 years. The radiative properties of atmospheric gases were not determined after the theory of AGW was developed. Further, to dismiss Freud and Marx out of hand suggests that you're either not a careful student of history or that you yourself are doing what you rail against: starting with ideology and trying to fit the facts.
  49. Understanding climate denial
    Skywatcher's comment directly addresses your use of Doll: "The relationship between CO2 and longwave IR was first experimentally observed in the 19th Century! You do know that you yourself can conduct a CO2 experiment with a couple of bottles, a couple of thermometers and a source of CO2?" John Tyndall also had few preconceptions when he worked on the radiative properties of gases in the 19th century. He certainly had no agenda re the theory of AGW, just as Doll, much later, had no agenda with smoking. The theory of AGW has been developing for almost two centuries, elsa. Tens of thousands of observations and experiments have been done that corroborate and confirm the radiative properties of CO2 and other atmospheric gases. I'm wondering if this is the appropriate thread for this discussion. This discussion is either highly appropriate here as an example, or, hopefully, it is not at all appropriate and needs to move to other threads (already suggested and linked).
  50. Models are unreliable
    I have been corresponding with an ex-engineer with regards to skepticism regarding anthropogenic climate change. Here is one of his remarks. "We certainly do not have the computing power to perform the ANOVA for the effect of orbit/tilt, solar output, geological processes, etc. on GTA. That makes attempts to correlate recent measurements of GTA with its inputs otiose." Basically, he believes that we are applying way too much certainty with regards to CO2, and understating our uncertainty with regards to other variables. I can debunk this at a qualitative level, but not quantitatively because I truly have no expertise in computer science. Can anybody help me out here, or is he right?

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