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Comments 68101 to 68150:

68101. RW1 at 10:57 AM on 15 December 2011
       Clouds provide negative feedback
       I'm a bit late on this. We all agree that clouds both cool by reflecting the Sun's energy and warm by 'blocking' or delaying the exit of surface emitted energy, but this is rather trival to the fundamental question of the net cloud feedback, is it not? The biggest problem is in the current climate, the net effect of clouds globally averaged is to cool by about 20 W/m^2, as is even acknowledged in papers claiming to show net positive cloud feedback (i.e. Dessler 2010), and is consistent with net negative feedback from clouds. This discrepancy would have to be explained in the context of strong net positive feedback from clouds on incremental warming, would it not? Not only is this not explained either by Dessler or anyone else to my knowledge, but without knowing physically why the net effect of clouds is to cool by 20 W/m^2 in the current climate, there is no way to know if the assessments of net positive feedback on incremental warming are accurate, let alone even physically possible. Ultimately, the fact that no one purporting evidence of net positive cloud feedback can explain this or even tries to explain it in light of the conclusions of their work, is rather telling to me how weak and unsubstantiated the case for net positive cloud feedback actually is. And while globally averaged, the water vapor concentration and water vapor feedback in response can further increase temperatures in a warmer world, it cannot be separated or isolated from the cloud feedback, as the two are constantly interacting together to maintain the current energy balance. This gets back to my point about the water vapor and cloud feedbacks already operating in a very dynamic manner in the current climate's globally averaged state from the forcing of the Sun. From this, let's look at the fundamental question of climate sensitivity, net feedback, etc. from the basic constraints dictated by conservation of energy. If the surface of the Earth is the warm by 3C, it must emit 406.6 W/m^2 from S-B (assuming an emissivity of 1 or very close to 1), which is +16.6 W/m^2 from the current global average of 390 W/m^2. Conservation of Energy dictates this +16.6 W/m^2 flux has to be entering the surface from the atmosphere on global average if it is to warm by 3C. There are really only two possible sources for this required energy flux into the surface, and that is either from the Sun via a reduced albedo or from increased atomspheric absorption (like from water vapor). If the current averaged state of the atmosphere is only going to provide +6 W/m^2 (+1.1C) from 2xCO2 (3.7 W/m^2 directly from the CO2 'forcing' and the remaining 2.3 W/m^2 from the current average opacity of the atmosphere; 3.7 W/m^2 x 0.62 = 2.3 W/m^2), where is the additional 10.6 W/m^2 needed for the 3C rise coming from? Can anyone explain and quantify the actual physics of how about a 1 C rise in temperature will change the atmosphere in a way that will further cause an additional 10.6 W/m^2 flux into the surface? If you think it will come primarily from increased water vapor, are you claiming that the water vapor absorption will increase by 10.6 W/m^2 from a 1 C rise in temperature (actually more than 10.6 W/m^2 because half of what's absorbed by the atmosphere escapes to space as part of the flux leaving at the TOA), and if so based on what data or physics? Or if you think the combined cloud feedback will cause a large portion of it, in what specific physical way? If by letting in more sunlight, how does increasing water vapor cause decreasing clouds or more transparent clouds? If by causing increased atmospheric absorption through more clouds, how is this specifically more than the incremental power reflected from the additional or thicker clouds? How is this rectified with the fact the net effect of clouds is to cool by about 20 W/m^2 in the current climate? In general there seems to be a lot of hand waving in regards to this fundamental question and answers to it tend to only be vague, generalized statements like "it comes from the all the feedbacks" or "from downward LW", etc. This kind of sloppy and incomplete scientific reasoning is not good enough. The required energy entering the surface for a 3C rise has to be coming from somewhere specific and from some specific physical process or combined processes that can be corroborated by some real, observable, quantifiable physics and data. I see mosly heuristic assumptions and more or less wild guessing dressed up as some kind of quasi 'best estimate' or 'educated guess'.
68102. skywatcher at 10:50 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       Eric, GCR does not need to be added to anything, as there is still, despite many requests, no mechanism for how it would operate. Cute model pirate ships don't need to be added to the models either. Others have already said the mercurio is junk science and should not be relied upon, one last example is he does not suggest the primary hypothesis for the PDO, that it is simply the integrated result of ENSO (Newman et al 2003). You keep saying 'potential' this, 'possibly' that in relation to GCR, but the reality is there's nothing there to hang your hat on. Sphaerica has it right above.
68103. tmac57 at 10:46 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       KR-

       It unfortunately represents a redistribution of wealth away from some vested interests, who are spending rather large sums lobbying for Business As Usual...

       It needn't be that way,in my view,if those vested interests would throw their considerable capital investment power behind alternative energy development.That way they can immediately drop their disinformation campaign,and keep all that money that they are funneling to politicians and advocacy groups,and go full bore into a cleaner future,and a safer world for themselves,their children,and grandchildren,and be genuinely proud of the business that they are in,instead of having to manufacture artificial advocacy using deceitful tactics.
68104. Tom Curtis at 10:37 AM on 15 December 2011
       We're heading into an ice age
       scaddenp @252, this press release from NASA details some of the latest research. In essence, models predict a slowing of the Atlantic Conveyor with increased melt water because fresh water is less dense than salty, and hence less prone to sink. Josh Willis has used buoy data and satellite data to show the Atlantic Conveyor sped up by 20% from 1993 to 2009, contradicting earlier ship-based data. There has been no statistically significant change from 2002-2009. The acceleration is attributed to a possible natural cycle. However, I would note that Greenland ice melt has primarily been in areas where it would feed the Labrador current. Further, because of the reducing volume of sea ice, it is not clear the more extensive summer melt back results in more fresh water being introduced to the Arctic Ocean. The point is that there are obvious complexities in this issue, not all of which I have covered (or are competent to cover). If you want to become up to date on the issue, this google scholar search will get you started ;)
68105. scaddenp at 10:27 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       >You have the burden of proof wrong. No. This is science not law. What science is about is finding the model that best explains observation. >I don't have to provide an alternative to natural >variability because that is the null hypothesis. All variation in climate has causes. We have an excellent model of natural forcing changes that have caused climate change in the past. We can also see that these natural forcings should be cooling the climate if any when in fact we are warming. (see here. In fact, read the report so you actually know what the science says. "That is why you have the burden of showing that the warming spike we are currently in is due to CO2 and not the other causes (whatever caused the warming in 1100 AD or 3000 BC)." Our current climate theory has no problem accounting for these past warming event (did you know that?), but struggles to explain current warming without anthropogenic factors. Policy has to be informed by theory that works.
68106. Zen69 at 10:26 AM on 15 December 2011
       Arctic sea ice has recovered
       Thanks, thats great. I am not sure I have a full understanding but it is certainly much clearer. I would just like to clarify that I have got your explanation right by puttting what you say into my own words. The PIOMAS model is designed to make estimates of ice volume by using measurements of ice thickness which have been taken by submarine. The model then adds estimates of the amount of ice it expects to find in other areas and from this it gives a trend. (I am not sure how these estimates are arrived at but I'm guessing it is complex and I am not too worried about this). These measurements are combined with satellite measurements of area covered from which we can determine volume. As well as measuring surface area, the satellite can also measure the amount of ice thickness in areas where it can be seen above sea level and from this it is possible to calculate total thickness in the way you have explained. Measurements of ice thickness is also taken using various other methods - drilled sample readings etc To check the accuracy of the PIOMAS estimates, ice thickness is checked in areas where it has not been checked previously by using the various methods we have already talked about. Results from these checks show that the estimates are pretty good but tend to have a bias towards overestimation of ice thickness. Just to add to this myself, it means that whenever we see these charts that show the rate of loss in ice volume, these are conservative estimations and the loss is probably greater than that shown. Is that about right?
68107. Bob Lacatena at 10:09 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       83, skept.fr,

       But I think I have now a clearer idea of how skeptic is "Skeptical" Science.

       Let's see. Some people disagree with you, and say that you have failed to make a coherent point, therefore this entire web site dedicated to presenting and clarifying the science is disingenuous. Yes, that makes sense. And your agenda is now crystal clear to everyone.
68108. Roger Gram at 10:06 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       14 Sphaerica, --"maybe a simple question along the lines of 'did you consider this?'" Actually, I raised such a question in response to the Part 2 post. "...veiled...implications of impropriety and deceit" You might re-read the comments and re-examine your thinking that led to these bitter words.
68109. Rob Painting at 10:00 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Richard Arrett @ 19 - "If CS turns out to be 1.3C - that will imply there is no indirect amplification feedback." How exactly is that supposed to work given that we know that the Earth was both much warmer and cooler in the past? If, as the fake-skeptics claim, the Earth is so insensitive, why has the Earth's climate changed so much over long timescales? And why is there such a strong relationship between CO2 and global temperature? (see below) See that's the problem with fake-skeptics, their ideas are negated by observations, and don't make any sense. And worse yet, they continually contradict themselves. One minute the 'climate is always changing', the next 'climate sensitivity is low.' Why is it now, when humans are pumping vast quantities of a powerful greenhouse gas into the atmosphere, that some never before observed, and inexplicable in terms of the physics, low sensitivity is supposed to ride to our rescue? That is why fake-skeptics are summarily dismissed by the scientific community. We need to focus on facts, not wishful thinking and self contradictory fake-skeptics.
68110. muoncounter at 09:50 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       Eric#103: "I am however still interested in GCR due to its potential modulation of water vapor feedback." As we've seen, the most recently published results consist of Dragic, Love 2011 and Laken, all reporting that this 'potential modulation' is either minimal, undetectable or non-existent.
68111. KR at 09:44 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       skept.fr - Side note: I can understand being tired of a particular discussion, but I do not believe that excuses the rather snarky tone of your post. Yes, most increases are coming from developing nations. But currently the 10 largest emitters (here, pg. 13) are in order China, the US, India, Russia, Japan, Germany, Iran, Canada, Korea, and the UK - together accounting for >65% of world emissions. Action by these nations (most of which _cannot_ be considered to be 'developing nations') can have significant effects on the rate of climate change. China has some of the largest investments in renewables in the world. In the US wind and solar are the fastest growing segments of the energy market - hardly an indication of lacking economic viability. In regards to baseline power (somewhat off-topic here), I would suggest looking at (and commenting upon) the Can renewables provide baseload power thread, where this myth is discussed. Considering fossil fuel 'cheap' power depends on ignoring the real, total costs of fossil fuels - including the external costs. Costs that will be paid by all (including developing nations) regardless of your accounting. Developing nations are growing rapidly, and will be an increasing part of the issue - but not yet. Hmm... wouldn't it be a good idea to head the problem off, and work together to minimize the high growth developing nation energy use impact on climate change? Helping all to create new power systems, increasing power availability, that don't pollute? Rather than throwing ones hands in the air, claiming (as you have) that limiting fossil fuel usage will crush developing nations? I think renewable energy development can be a definite win-win scenario. It unfortunately represents a redistribution of wealth away from some vested interests, who are spending rather large sums lobbying for Business As Usual, along with ideological interests who feel that any regulation of even potential freedoms for the common good is untenable - the situation here, at least, in the US. From that come the 'skeptics', pushing inconsistent and contradictory hypotheses that don't account for the facts, and from that come things like RealClimate and SkS - where the facts are (as best they can be) discussed. --- And yes, I would agree with you that "Readers will appreciate how clearly my different points and concerns have been answered here". Although I expect that my opinion on their reactions will differ from yours...
68112. chris at 09:33 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       O.K. fair enough angliss. I guess this shows the rather subjective nature of the choices associated with these analyses! I read Jim Powell's top "article" to be a consideration of skeptic papers involving a "case against human-caused global warming", and "that denied or attempted to cast substantial doubt on human-caused global warming". You stated above that Douglass et al (2008) "suggested that the climate isn't warming....", which would (if true) certainly accord with Jim's criteria. However you now say (and I agree) that Douglass et al are actually suggesting that their (atrociously flawed!) analysis indicates it's not going to warm in the future as much as model projections suggest. Does that accord with Jim's criteria of "a case against human-caused global warming" etc? Debatable methinks. But it's a subjective consideration!
68113. ahaynes at 09:24 AM on 15 December 2011
       Infrared Iris Never Bloomed
       From Reisman - ""Science is at its core about reproducibility." If the result is reproducible or replicated by multiple scientific organizations or scientists, then it is more acceptable than that which is not. Both Santer and Mann seemed to agree that the Iris Hypothesis did not stand up to scientific scrutiny."
68114. chris at 09:20 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Richard (#18) says "I don't have to provide an alternative to natural variability because that is the null hypothesis." oh dear... choose a scientifically-deficient "null hypothesis" and bob's your uncle - you can then simply reject everything that we know! However, the "null hypothesis" isn't the hypothesis based on completely discarding all our knowledge. In fact if one takes your "hypothesis" that warming since the mid 19th century (say) is due to "natural variability", then you have chosen a hypothesis that simply doesn't accord with the scientific evidence base.
68115. angliss at 09:16 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Sphaerica (#14) - Odd, I thought I had specifically suggested to Jim that he add Douglass et al 2008 and got no response. I'm not trying to imply that Jim did anything on purpose, but rather point out that he may have accidentally filtered out papers like Douglass et al 2008 because of the way he designed his search parameters. FWIW, I'm not using "bias" in the colloquial sense here - I'm using it as I would in my day job as an EE: bias is a detectable and correctable error independent from random processes like noise. I apologize for not making that clearer in my initial post. Chris (#15) - I have read the paper, although admittedly not recently. On a quick skim of it, however, I found this in the summary: (The use of tropical tropospheric temperature trends as a metric for this test is important, as this region represents the CEL and provides a clear signature of the trajectory of the climate system under enhanced greenhouse forcing.) On the whole, the evidence indicates that model trends in the troposphere are very likely inconsistent with observations that indicate that, since 1979, there is no significant long-term amplification factor relative to the surface. If these results continue to be supported, then future projections of temperature change, as depicted in the present suite of climate models, are likely too high. Also: The last 25 years constitute a period of more complete and accurate observations and more realistic modelling efforts. Yet the models are seen to disagree with the observations. We suggest, therefore, that projections of future climate based on these models be viewed with much caution. IMO, this meets Jim's criteria as described in his first post. Regardless, I am sorry for not suggesting this paper's inclusion it back on Post 1, as doing so might have avoided any unpleasantness.
68116. Dave123 at 09:14 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Richard...what **global** warming spike at 1100 AD? I'm only aware of regional high temperatures smeared out over a couple of hundred years. For that matter, all the hockey sticks I'm seeing for **global** temperatures don't show anything at 3000 BC either. ps... I'm sure not going to be around in 2100. Nor are my children likely to be. If I had grandchildren right now, it wouldn't be a good bet either. How do you plan to be around in 2100?
68117. ahaynes at 09:13 AM on 15 December 2011
       Infrared Iris Never Bloomed
       FYI Dana, Lindzen begs to differ with your assessment, and has a powerpoint presentation with counterarguments for at least the early-2000s papers. The argument-counterargument volleys are over my head, at least as much of same as I want to devote to this. So, 2 Qs - First, what heuristic does the non-expert use in a situation like this? I think the answer is to ask: do unrelated scientists looking into your hypothesis think that the evidence from their research supports it? (If I'm the scientific bystander, and the hypothesis-holding scientist stands his ground, is there any other way I can go about forming an informed view?) And second, not using a heuristic, could someone please (of the expert ilk) address some of Lindzen's counterarguments, e.g. that Lin et al 2002 were "ignoring the fact that we were taking Ac(260) as a surrogate for all tropical upper cirrus, and instead asserting that the clouds defined by Ac(260) were essentially the only clouds we were considering.")
68118. Dave123 at 09:09 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       @16. So what you're saying Richard is that you can't take initial boundary conditions in say 1970, run a suite of models through 2010 that show good correspondence to the real temperature trends and use the climate sensitivity coming out of that? That you can't use paleoclimate data to calculate prior climate sensitivity and apply those estimates to present conditions? What is "knowing" to you anyhow? You've got an unstated premise/bias in there that needs to be laid out. Do words like 95% confidence mean anything to you? Are there other areas of knowledge where calculations are done that you also require waiting for? I keep thinking of the mention of a mole on your skin in another post. The individual variability of cancer progression is large...so why should you trust the past clinical data and progression models?
68119. chris at 09:07 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       We've got lots of actual observations Richard (#16). For example, the earth has warmed by around 0.8-0.9 oC since the middle of the 19th century, while [CO2] has risen from around 286 ppm then to 389 ppm now. A climate sensitivity of 2 oC should then give an equilibrium warming of: ln(389/286)*2/ln(2) = 0.87 oC We know that we haven’t had the full warming from this enhancement of greenhouse gases, since it takes the earth many decades to come to equilibrium with the current forcing resulting from raised greenhouse gases. Likewise we know that a significant part of the warming from this enhancement of greenhouse gas levels has been offset by manmade atmospheric aerosols. On the other hand some of the warming is due to non-CO2 sources (man-made methane, nitrous oxides, tropospheric ozone, black carbon). Non greenhouse gas contributions to this warming (solar, volcanic) are known to be small. Overall, it’s rather unlikely, given the warming since the mid-19th century, that climate sensitivity is less than 2 oC. This is expanded on in more detail in Knutti and Hegerl, in Murphy et al. (2009), in Rind and Lean, 2008, in Hansen et al (2005), etc. etc. So the evidence simply doesn't support a climate sensitivity that is below 2 oC. The evidence in fact supports a climate sensitivity of around 3 oC at maximum (evidence-based) likelihood. It's silly to make arguments based on the premise of ignorance! In science we assess hypotheses on the basis of the evidence.
68120. Richard Arrett at 09:06 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Dave123 @17: I guess we will have to agree to disagree on who has the burden of proof. Personally, I plan on measuring the average global temperature at 2100, and the sea level rise at 2100. Then we will have actual observations which we can use to determine the climate sensitivity. If CS turns out to be 1.3C - that will imply there is no indirect amplification feedback. If CS turns out to be 3C or higher - you are right. If CS turns out to be 2C or lower - skeptics are right.
68121. Richard Arrett at 09:01 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       scaddenp #10: You have the burden of proof wrong. I don't have to provide an alternative to natural variability because that is the null hypothesis. What caused the warming spike around 1100 AD? What caused the warming spike around 3000 BC? The CO2 data (ice cores) tells us it couldn't have been caused by CO2 - because CO2 was constant at around 280 ppm for during both of those temperature spikes. That is why the null hypothesis is natural variability. That is why you have the burden of showing that the warming spike we are currently in is due to CO2 and not the other causes (whatever caused the warming in 1100 AD or 3000 BC).
68122. skept.fr at 09:00 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       #81 KR : OK, my apologies for the misinterpretation of your sentence : "And yet - you seem to repeatedly call for "go slow" approaches, to minimize economic shifts or disruption, to 'tone down' the urgency. This despite the (acknowledged) lead time required to shift energy production from fossil fuels." It sounds to me as if I was supposed to leave or silence all my doubts because of a urgency to act. But it was not your thought, so sorry. "given the observed intransigence of the fossil fuel industry and conservative politicians" No. Like the Sphaerica's "magnats", this is a typical misinterpretation of reality. Look at Peters et al 2011 article I already quoted, nearly all the increase of CO2 emissions since 1990 come from non-OECD countries who're escaping poverty. And so for the projected decades, as IEA WEO 2011 put it : "The dynamics of energy markets are increasingly determined by countries outside the OECD. Non-OECD countries account for 90% of population growth, 70% of the increase in economic output and 90% of energy demand growth over the period from 2010 to 2035." So even if the last 15 years US blockage to climate decision is a pity, partly due to lobbies, you should IMO leave this Western-centric view of the energy-climate problem for the future, because even US is henceforth a small part of this problem. (At least, carbon intensity of US economy made small progress, this is not at all the case when a poor country begins its development.) In real choices for developing countries, the problem is not the fossil fuel industry (not speaking of Western conservatives), it is the incapacity of wind and solar industries in their current technologies to provide the regular, large and if possible cheap basis for an energy infrastructure needed at a national scale. And also to provide fuel for transportation, of course. BRICs and other developing countries are not foolish, if non-fossil solutions were the most interesting for their energy mix, their would have chosen this way for a long time: no pollution, no dependency of foreign providers, no climate warming... # 82 Sphaerica : the French expression for your repeated claim is "procès d'intention", I don't know the English counterpart. I'm tired too. But I think I have now a clearer idea of how skeptic is "Skeptical" Science. Readers will appreciate how clearly my different points and concerns have been answered here.
68123. Dave123 at 08:58 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       @12- "It has been" warmer/cooler "in the past when CO2 was 280 ppm". A. There is no such thing as "natural variability" in the sense that things move around with no recourse to a physical explanation....which is what I hear whenever someone on the "skeptic" side uses that phrase...unless they mean "it's too complicated for me to figure out, so you can't understand it either". B. Your statement is pointless unless you also hold all other variables constant... insolation, albedo etc. And you need to be clear on whether this is a stable or transient condition. Do you have that information? C. And for SkS you really ought to cite the dates, and the papers providing the temperature and CO2 information and other control information. Anything else just isn't up to standard. D. I submit that this data has been developed, presented in peer reviewed papers, and summarized and presented here on SkS. That in sum your statement that it has been warmer and or colder at 280 ppm, and implying that all other things are equal is in fact false because it has been shown all other things aren't equal. E. And if you have been immersed in this discussion through sites providing direct access to peer-reviewed literature...such as SkS and RealClimate you'd have to say that given the data on the table, for a skeptic to make a case they must refute it. The ball is in their court, the burden of proof is on them.
68124. Richard Arrett at 08:55 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Sphaerica, #8: We don't actually know that. We know from physics that we should experience around 1.2C by 2100 from the direct effects of CO2 warming. However, what is in question is the amount of indirect feedback. There are lots of theories and projections - but no actual observations. So until we can actually measure temperature and/or sea level when 2100 rolls around, we don't actually know what the climate sensitivity number will be. It may be 3C or it may be 1C - we just don't know.
68125. Bob Lacatena at 08:53 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       106, Eric, Except GCR can't be added to the model physics because no one has demonstrated a working mechanism and defined the underlying physics needed to incorporate it into a model. By contrast we know the exact bands at which CO₂ absorbs radiation, the emission times, the density throughout the atmosphere, the overlap with other gases, the resulting TOA emissions spectrum, the energy associated with each photon, and 80 bazillion other details that allow us to directly model the physics. For GCRs we have "hey, look, there was maybe sort of a correlation over a several million year time scale, given a window of tens of millions of years, give or take, and a questionable proxy for the strength of GCRs, and no correlation whatsoever in recent, hard, direct instrumental measurements." GCRs are a non-starter until someone does a lot more work and gets some positive results from it, and I don't expect that to happen for a decade at least, if ever. Including GCRs now might as well be accompanied by the well-considered effects of Eurasian Leprechaun Farts (ELFs, a well-known Christmas time seasonal impact).
68126. chris at 08:50 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       angliss (#9), that's simply incorrect. Nowhere in Douglass et al (2008) is it suggested "that the climate isn't warming because the analysis erroneously concludes that there's no evidence for tropical tropospheric warming". It's very easy to establish that fact - one simply has to read the paper! You seem to be arguing on the basis of an easily-established false premise. Douglass et al are very clear that they are addressing something rather specific. Santer et al (2005) determined that apparent differences in modeled and measured temperatures in the altitude-dependence of temperature trends in the tropical zone during the satellite era is not an indication that there is fundamental discrepency between models and measurements since the uncertainty in the latter overlaps with the variance in the models. Douglass et al's reanalysis purported to show that the uncertainties are actually sufficiently small that a strong statement about fundamental discrepencies in models and measurements in this subset of tropsopheric data can be made. Of course Douglass et al's analysis was pathetically flawed. But that's not the point. In the context of this thread, Douglass et al's analysis has nothing to say about whether the climate is warming or not, nor the origins of warming. In fact Douglass et al state completely explicitly that the climate is warming (see their Table 1) since they accept the very marked surface warming trends that are well established.
68127. Bob Lacatena at 08:43 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       angliss, Roger Gram, Do you think it might have been possible to simply post a comment saying "Hey, you missed one, what about the Douglass 2007 paper?" rather than: (a) Implying that Jim didn't try hard enough

       "If you want to list all the skeptic's papers, you need to look more carefully. "

       or (b) Implying that his entire method of locating papers was perhaps biased towards getting some sort of desired result

       "questions that need to be asked about why, and whether the methodology might be inadvertently biasing the results of the study"

       Hint: I'm sure Jim would gladly add this paper, and any others you find, to the list. I'd further point out that in part 1, Jim explicitly gave reasons for not including Klotzbach et al. (2009), which appears in many ways to be similar to the Douglas paper. Once again, maybe a simple question along the lines of "did you consider this?" would have served better than veiled (whether purposeful or not) implications of impropriety and deceit? Consider Jim's comment here, on part 1, which ends with the statement:

       I welcome suggestions for papers I missed, as Troy has done.

68128. Eric (skeptic) at 08:43 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       Either the GCR needs to be added to model physics or it will have to be ignored. Very short term empirical analysis, although still requiring a model, should not need GCR included as we see from the Laken and other papers. For solar cycle sensitivity-based estimates, I don't see how GCR can be ignored if it has any role at all. For longer term empirical it probably needs to be in the model.
68129. Richard Arrett at 08:39 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       #6 Utahn: The part which requires that skeptics have the burden of disproving AGW.
68130. Richard Arrett at 08:38 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       #4 John Russell Again - this all depends on who has the burden of proof. It has been warmer in the past than it is currently, and CO2 was at around 280 ppm. It has been colder in the past than it is currently, and CO2 was at around 280 ppm. So, given that natural variability is the null hypothesis, don't you have the burden of showing why the current warming is due to CO2 and not to whatever caused prior warming spikes (while CO2 was at 280 ppm)? But to take a stab at answering your question, perhaps aerosols are an opposing forcing which are counteracting CO2.
68131. Bob Lacatena at 08:31 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       80, skept.fr, I am now officially beginning to tire of the latest denial tactic, which is to purport to have this huge interest in the welfare of the poor in third world countries, and that the only humanitarian way out for them is through more and more and more use of fossil fuels. You complain that my "fire age" metaphor is a scare tactic, and then calmly resort to the same by over and over implying that anything less than wanton, remorseless use of fossil fuels to lift the third world countries from the sludge would be a crime against humanity. Then you say there are lots of uncertainties in the science. Then you imply that fear-mongering is the business of certain climate scientists. Your words (and anyone here is free to go back and review them) call for delay, delay, delay for any reason you can think of — we're not sure, they're fear-mongering, it will hurt the poor. You seemingly want to mollify your conscience by saying you are in favor of pricing carbon externalities, and yet 99% of your words instead say "do nothing." I think you need to stop pontificating, state clear priorities and goals, and then start generating comments that are actually in line with those goals, rather than generating whatever stream of comments will help you arrive at the same, tired conclusion that "we really should wait on this whole get-off-of-fossil-fuels thing."
68132. KR at 08:17 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       skept.fr - "From an ethical stance, I can no more accept a 'end justify the means' approach, which is implicit in many critics of my position including yours." I would have to disagree most strongly with your interpretation, skept.fr. I do not believe I have ever stated anything of the sort, and consider that an unjustified Strawman distortion. My position is that climate change has significant, negative impacts, that addressing emissions will not cost too much, and will in fact actually save money over the mid to long term. And from that, that any delay in addressing CO2 emissions and climate change increases the cost of dealing with it. That doesn't by any means justify making stuff up, or running around like Chicken Little. But it certainly means being very clear what the range of likely climate impacts and costs are when discussing the matter. I would agree that drawing lines in the sand, lines that (given the observed intransigence of the fossil fuel industry and conservative politicians) are likely to be crossed - that is perhaps not terribly productive. But neither is soft-pedaling the cost of not acting, which appears to be what you would prefer (here, here, here, for example).
68133. Roger Gram at 08:12 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       7 Sphaerica, You seem to think that I'm defending the Douglass-Christy-Singer paper. But I'm not. Rather, I'm puzzled that a paper that claims to show that the models are wrong (and was trumpeted and celebrated in right wing and denialosphere sites) would not be included in a database of skeptical peer-reviewed papers. Your characterizing this paper as highlighting "one narrow area of inconsistency in the models" was clearly not shared by mainstream climate scientists. The reaction at the time by Ben Santer and RealClimate was one of surprise and alarm that such a paper could pass peer review and be published. There followed an intense effort to quickly rebut this paper, both on-line, and in the scientific literature. I applaud the work of Skeptical Science, and the effort to develop this database. However, I think the database is quite incomplete.
68134. skept.fr at 07:58 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       #78 KR : I write here on a web site called Skeptical Science. As Stephen Schneider once nicely put it in his famous reflexion about the 'double ethical bind', "as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts." (my underscore) So either SkS is bound to this scientific ethic, and for the long list of climate effect you mention (or Sphaerica in his text), it must also be precised the doubts, caveats, ifs, ands, buts. Or SkS is bound to a layman / militant ethic, and then it is ruled by the second part of Schneider quote : "On the other hand, we are not just scientists but human beings as well. And like most people we'd like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public's imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have." (my underscore). I already gave some precise examples for the Sphaerica 451 ppm world, notably the Fire Age metaphor that is not supported by vegetation-AOCM coupled model on a global scale and is misleading as such, without precision that the "fire" in question concerns some regions (and usually not at 451 ppm concentration in literature, rather a doubling CO2 a minima for model projections ; if I recall correctly 451 ppm is even under the SRES B1 concentration in 2100, and best estimate of the transient sensitivity for such forcing is quite low). And there are others. If you read carefully climate literature, you perfectly know that there is still divergence among AOGCMs on the amplitude and frequency of changes related to precipitation and temperature, and it is even more true for regional projections. Climate science is not just made of Hansen or Rahmstorf papers (whatever their quality), that's why IPCC exists. So, if you speak of droughts, you must recall that IPCC SREX 2011 just give of "medium confidence" for their increase ; if you speak of crops productivity, you must recall that IPCC AR4 WG2 suggest it will continue to increase with a 1-2K warming on low latitude and a 1-3K warming in high latitude, and that, with medium confidence, 'the marginal increase in the number of people at risk of hunger due to climate change must be viewed within the overall large reductions due to socio-economic development' (chapter 5). And so on. These are the 'buts', 'ifs', 'ands' of Schneider's scientific ethic. From an ethical stance, I can no more accept a 'end justify the means' approach, which is implicit in many critics of my position including yours. From a pragmatic stance, I observe the 'doom and gloom communication' strategy is a failure, either for changing personal / societal behaviors or to engage a world policy at successive COPs. These are two sufficient reasons to explain my point. Maybe some here are very happy to reiterate each year the game of COP hope-followed-by-delusion, I'm not. Maybe some here are happy with eternal complaining about 'human-selfishness-that-ignore-the-bad-consequence-of-his-action', without any perceptible effect on the selfishness in question, I'm not. I added a third point : human welfare is my ultimate concern, I don't think a climate-centered assessment of risk on this welfare is fair as we all know that climate mitigation is causally bound to fossil energy limitation. 'Euphemisms' (muoncounter) are everywhere in this debate: in current technology (no CCS available), the only method for not exceeding 450 ppm is to fix now a maximal quantity of fossil for each country and to forbid its use beyond this limit, including many non-OECD countries. Do you want that, yes or not? If yes, I tend to think that you defend a dangerous target for humanity, at least I wait a strong justification that adverse effects of a constrained energy shortage will not be more harmful that adverse effects of the avoided level of climate change. If not, you're probably somewhere in my zone of interrogation: what are the better solutions to promote now (and not in 2020, 2030, etc.)? As I already suggested, my fear is that the 2K/450 ppm target is a Pyrrhic victory for those who are interested in climate mitigation. I foresee a stagnation of climate diplomacy which ultimately profits to the "business as usual" scenario. Sphaerica insistance on the 451 ppm world seems to me a caution to this very likely failure. Maybe I'm totally wrong, maybe 194 countries will adopt without problem the post-Kyoto treaty in 2015, maybe energy transition will be easy and no country will abandon the treaty as some did for Kyoto.... In one sense, I hope so, but I've no rational argument to justify such a hope.
68135. Bob Lacatena at 07:56 AM on 15 December 2011
       (Fahrenheit) 451 ppm
       75, Arkadiusz Semczyszak,

       Many lines of evidence show that the variations in the CO2 growth rate are mainly caused by terrestrial effects...

       Citation please. Otherwise this is mere assertion. Even with a citation... where do you propose all of the CO₂ can be coming from, year after year, from "Nature." Your premise here is laughable. The CO₂ "budget" is closed, and we know we are the cause and what the rate of incline is. To suggest that we don't know when we'll reach 451 ppm is downright laughable. Your supplied citation, on the otherhand, contradicts your own statements. The paper studies uncertainties in the continued uptake of CO₂ by ecosystems, and the probability (as I stated in my post) that this uptake may reverse and instead release CO₂. The opening line:

       Recent evidence suggests that, on a global scale, terrestrial ecosystems will provide a positive feedback in a warming world, albeit of uncertain magnitude.

       From the conclusion:

       Overall, it is likely that, at least on a global scale, terrestrial ecosystems will provide a positive, amplifying feedback in a warming world, albeit of uncertain magnitude.

       Your comments on methane are a non sequitur. As I already stated clearly in my post, there are obviously known differences between a glacial termination and our current situation. No one, anywhere, ever said that the methane feedbacks that we expect are in any way comparable to what was experienced in the last glacial termination, so the fact that the mechanisms are different makes no difference whatsoever. Really, Arkadiusz, you can do a better job of expressing complete and total denial than this.
68136. scaddenp at 07:52 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       And as an observation, you seem to still engaged in trying to find evidence for low sensitivity which you appeared to decided is likely a priori rather than from evidence in front you.
68137. scaddenp at 07:51 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       You can get sensitivity directly from model, or you can get sensitivity from empirical methods from past climate events. In the former, its pretty hard to see how you could change sensitivity because you have to have physics to add GCR into climate. Lacking evidence or proven mechanism, then that is pretty hard. For empirical methods, then effectively GCR is already included because there is no way to sort out different factors in such studies without a model.
68138. scaddenp at 07:45 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Richard - AGW is not so much an "hypothesis" but a result from our current theory of climate. It could be wrong but you have to explain what is wrong with known physics first. (For instance, why does measured increased radiation from the atmosphere not cause warming). Climate sensitivity is know with considerable certainty to lie between 2 and 5, with a most likely value around 3. Even low end is cause for concern. No scientific theory is even "known to be correct". That doesnt stop us using incomplete theories like gravity for sending rockets to mars. Before you can claim natural variability is responsible you need a credible theory for some natural variability. None has been found. By contrast, normal climate physics has no trouble explaining current observation. So, as far as policy is concerned, would you bet on what is well established in science? or the hope that some magic source of variability will be found to let us off the hook? Which do you think is prudent practise? Would let a strange mole continue to grow because your Dr is uncertain whether it is cancerous or not?
68139. angliss at 07:43 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Sphaerica, #7: Part of Roger's point is that Jim's database doesn't include a bunch of papers by "skeptics," including that one. That Douglass paper clearly suggests that the climate isn't warming because the analysis erroneously concludes that there's no evidence for tropical tropospheric warming, so why wasn't it included in the analysis? It's a fair question, and one I have as well, even though I tend to agree with the analysis' conclusions. If Jim's methodology failed to catch this paper, then there's some fair questions that need to be asked about why, and whether the methodology might be inadvertently biasing the results of the study.
68140. Bob Lacatena at 07:39 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       3, Richard Arrett, We know definitively that climate is not changing due to natural variability. We have narrowed climate sensitivity down to a small enough range, with enough redundant confirmation, that we are fairly confident in what it is going to mean going forward. At this point, the strength of the science is so overwhelmingly strong that the burden does fall on the "skeptics" (a laughable moniker) to provide some evidence that somehow, somewhere, there is something solidly wrong with current theory. This entire series of posts shows that despite how desperately some people would like to do that, how many of them there are, how well funded they are, and how much time they have put into the effort, none of them have come remotely close to even denting the mainstream science, let alone damaging it. Doesn't that tell you something?
68141. Bob Lacatena at 07:34 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       1, Roger Gram, How does the paper you supplied in any way affect the content of this post? Which bullet point in part 2 does it contradict? In particular, however, this particular paper attempt to make a case (one not broadly accepted) for one narrow area of inconsistency in the models, but then leaps to the grand conclusion that because of this supposed inconsistency, the models are entirely suspect and therefore the entire theory of AGW is suspect. You can't see the fallacy in this?
68142. scaddenp at 07:28 AM on 15 December 2011
       Newcomers, Start Here
       imthedragn. If you really want to go into all the gory detail, then can I suggest you work through CO2 series at Science of Doom. You will find all that detail in that extended series.
68143. scaddenp at 07:24 AM on 15 December 2011
       We're heading into an ice age
       'good chance that the arctic melting will stop the Atlantic conveyer by dumpling lots of fresh (therefore lighter) water into the North Atlantic.' I dont believe there is any science supporting this, but please feel free to cite some. There is a postulate (and evidence) that the massive dump of fresh water from ice sheet melting caused a slow down and thus the YD event. However, this was an extremely rapid dump of a lot of water. Summer melt of seaice over many years is in a different order. Even if the Milankovich cycles were strong enough to cause another glacial with CO2 levels this high, the onset is extremely slow - 2 orders of magnitude less than current rate of change. It not a question of whether we would prefer warm or cold - its the rate of change that is dangerous.
68144. Eric (skeptic) at 07:18 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       scaddenp, GCR was always a dead issue to me for explaining current warming. Now it is less clear to me over the long run also. I am however still interested in GCR due to its potential modulation of water vapor feedback. What I would like to see is a study examining uncertainties in climate sensitivity due to uncertainties in GCR.
68145. Utahn at 07:09 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Richard Arrett: "Therefore, your conclusion is premature (in my opinion)." Which part of the stated conclusion do you find premature?
68146. DrYew at 07:06 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Hi - It would be useful to get the following simple numbers: 59 skeptic papers are listed... since when? And 59 of how many climate change papers (ie, what was the pool of candidates?) How many authors are uniquely identified in the 59 papers? How many authors are uniquely identified in the pool of candidates? This data would give some sense of consensus DrYew
68147. Eric (skeptic) at 07:05 AM on 15 December 2011
       Galactic cosmic rays: Backing the wrong horse
       Lucky for me, Dr. Laken took part of his evening to explain the TSI-GCR link. Over the long run an active sun means more TSI and an active sun means less GCR (due to more solar wind). The measurements of solar activity are smoothed and somewhat qualitative sunspot counts and TSI and GCR are running averages or proxies. Everything works the way I thought. But on a timescale of days the TSI relationship to GCR is complex due to positioning of the sunspots and other features and the movement of those features. So TSI and GCR (and solar UV) have more complex relationships including time delays. The wording in the abstract refers to those short term relationships (because that is what the paper is about).
68148. John Russell at 07:03 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       @Richard Arrett #3 "This warming which has occurred from 1850 to the present, could still just be a coincidence..." Could it? I think then you need to explain how the a massive increase in CO2 hasn't caused the planet to warm. You're denying the accepted physics of the greenhouse effect -- so you need to provide a convincing alternative explanation.
68149. John Hartz at 06:50 AM on 15 December 2011
       2nd law of thermodynamics contradicts greenhouse theory
       KR: Having followed the multiple, lengthy exchanges between TOP and you and other SkS authors, I am firmly convinced that TOP's sole purpose is to litter this comment thread with excerpts from the G&T paper. In my opinion, this behavior ought to be against SkS Comment Policy. If it were my call, I would ban TOP from posting on SkS and delete all of his comments.
68150. Richard Arrett at 06:48 AM on 15 December 2011
       Is there a case against human-caused global warming in the peer-reviewed literature? Part 3
       Doesn't your conclusion depend on which side has the burden of proof? I thought that AGW was a hypothesis. I thought that the data was consistent with the hypothesis. However, I also thought that the data was also consistent with other hypotheses, and that we did not have enough data to rule out one or the other yet. We don't even know with any certainty yet was the climate sensitivity number is. Therefore, I thought that we did not yet have enough data to definitely say that AGW was correct. So your conclusion is only correct if skeptics have the burden of disproving the AGW hypothesis. My understanding is that skeptics do not bear the burden of proof. I thought the null hypothesis was natural variability, not AGW. The scientists who advocate human-caused global warming bear the burden of proof (I think). This warming which has occurred from 1850 to the present, could still just be a coincidence and correlated with the increased CO2 emissions, but not necessarily caused by them. Therefore, your conclusion is premature (in my opinion).
       Response:

       [dana1981] Incorrect.  AGW is a robust scientific theory which has withstood decades of scientific scrutiny, not a hypothesis.

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