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Doug Bostrom at 12:38 PM on 20 June 2010How climate skeptics mislead
This paper Bayesian approaches to detection and attribution (J.D. Annan, 2010, in press, Wiley Interdisciplinary Reviews: Climate Change) provides some useful food for thought about how we might more reliably tease out a useful message from climate research. It addresses some of BP's concerns. Abstract: We consider the Bayesian alternative to the classical frequentist approach to detection and attribution of climate change. Some of the notable advantages of the Bayesian paradigm include a more consistent approach to competing hypotheses, a coherent interpretation of all available data, and an intuitively natural interpretation of the results. Well worth reading. -
Doug Bostrom at 12:22 PM on 20 June 2010How Jo Nova doesn't get the tropospheric hot spot
A more accurate way of phrasing poptech's synopsis might be "The failure of a warming trend that is entirely consistent with model results has been shown in various papers..." A minor quibble, based on other folks such as McLean et al attempting to explain measured temperature anomalies in the tropics via SOA and other means. My point being, if there's no noticeable warming trend in the tropics it's hard to say why McLean would need to be creating alternative explanations for why there's a multi-decadal anomaly in tropic temperatures. Incoherence. -
MattJ at 10:06 AM on 20 June 2010Astronomical cycles
When this kind of pseudo-statistical reasoning is applies to stock market prices, it is called 'chartism'. I guess it is not just in the stock market that chartism continues to fool many even today, years after it was soundly refuted... -
johnd at 09:16 AM on 20 June 2010Astronomical cycles
These notes apply to the chart posted above. Figure TS.9. (Top) Distribution of linear trends of annual land precipitation amounts over the period 1901 to 2005 (% per century) and (middle) 1979 to 2005 (% per decade). Areas in grey have insufficient data to produce reliable trends. The percentage is based on the 1961 to 1990 period. (Bottom) Time series of annual global land precipitation anomalies with respect to the 1961 to 1990 base period for 1900 to 2005. The smooth curves show decadal variations (see Appendix 3.A) for different data sets. {3.3, Figures 3.12 and 3.13} -
johnd at 09:12 AM on 20 June 2010Astronomical cycles
HumanityRules at 03:41 AM, in addition to the various factors illustrated, perhaps the annual precipitation cycle has a place. Whilst it may be indirectly represented, perhaps by ENSO(?), precipitation is a direct indication of a cooling influence both immediate and longer term as it replenishes and maintains a reservoir of soil moisture that are only significantly depleted by drought. This IPCC chart at the bottom gives an indication of the cycle as observed in the 20th century.
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Riccardo at 08:28 AM on 20 June 2010Astronomical cycles
HumanityRules, "what she seems to do is develop a model which has reasonable match to HADCRUT then derive the anthropogenic signal from that model." This claim is compleately unfounded. Please stick to what she said in the paper and do not try to make people say what you'd like them say. shawnhet, you assume that: 1) i'm supporting the n=4 versione of the trend; 2) i'm a competitor to Scafetta. Neither is true and nothing i said should let you think they are. I esplcitly stated (several times indeed) that the n=4 has no more value and I nowhere tryed an alternative hypothesis. Insisting on this point is, at best, specious. I'll said it again, maybe sooner or later you'll will accept it. I just showed the weakness of Scafetta paper through its arbitrary choice of the trend. Stop. I understand that it's hard to accept the fault one of the skeptics heros, but you know, sometimes even heros might be wrong. As for the "competitors", aka currently accepted hypothesis, again as said countless time now, there are plenty of papers, one of them quoted before. I'm sure you know many more. There's still something missing? Sure, hardly a breaking news, you will hardly find someone claiming the opposite. It's still a topic of active research for a reason. For sure what is missing is an "alternative" hypothesis and the astronomical cycles theory is not (yet?) up to the task. -
Alexandre at 07:32 AM on 20 June 2010How Jo Nova doesn't get the tropospheric hot spot
Chris Colose #15 Thank you very much for your response. Now I think I understood it: without a lapse rate, you cannot "see" other temperatures from the top of the atmosphere, so there would be no GHG "bite" in the OLR spctrum. So if the hotspot were not there, then the lapse rate would be probably greater (greater temperature drop with altitude), and hence the intuitive conclusion that the climate sensitiviy would also be greater. Thanks. -
shawnhet at 06:48 AM on 20 June 2010Astronomical cycles
Riccardo, I guess I don't really understand what you're up to here. Scafetta is attempting to reconstruct the observed temperature record by combining a cyclical component (initiated by changes in the SSCM) and a given trend. I don't really know if he does a good job of this or not. You, OTOH, seem to be claiming that because your n=4 trend more closely matches the recent temp trend, then apparently it is superior (or at least equal to) Scafetta's, but really this is apples to oranges. Scafetta, purportedly has an explanation for warming for the entire record, you, at best can only explain the last 30-40 years. For periods prior to that you still have essentially the same fluctuations(Fig. 3) in temp that Scafetta tries to explain by referring to SSCM. An effective competitor to Scafetta's hypothesis would need to explain the same data that he did, not simply choose one portion of the data, and calculate a trend on that basis. Cheers, :) -
Doug Bostrom at 05:58 AM on 20 June 2010Astronomical cycles
Something that bothers me about Scafetta's paper is the seemingly combative or biased attitude he drags into the conclusion section of his paper. He makes some statements that are plainly exaggerated or at least factually erroneous as well as citing other, unrelated research in an apparent attempt to bolster his findings with circumstantial evidence that he cannot show as related to his core thesis. For instance, Scafetta claims "...the AGWT promoted by the IPCC [2007], which claims that 100% of the global warming observed since 1970 is anthropogenic, is erroneous." Nowhere in the IPCC 2007 report can such an assertion be found; the remarks on attribution in the IPCC synthesis are heavily nuanced and qualified. Scafetta departs from a straight discussion of the relationship of his research to the IPCC summary to make an unfounded allegation. This harms his credibility for any reasonably informed layperson reading his paper, leading readers to conclude he's pursuing an agenda beyond scientific inquiry. Elsewhere in the discussion Scafetta mentions Solomon's work on stratospheric water vapor. By his own words, we can conclude that he's attempting to establish a conceptual space for unidentified climate forcings: "[Solomon 2010] reinforces that climate change is more complex than just a response to added CO2 and a few other anthropogenic GHGs." That's a plainly obvious fact and adds nothing to his thesis, but it certainly will help lead readers in the "correct" direction. He also makes a curious choice of words to describe Solomon's findings, saying "...stratospheric water vapor has largely contributed both to the warming observed from 1980-2000 (by 30%) and to the slight cooling observed after 2000 (by 25%)." We could agree that Solomon's work describes a significant influence, but largely? That word suggests that water vapor is a dominant effect but it's apparently not. Again, there's a clear tone audible here that goes beyond a simple spirit of curiosity. Further to Solomon, Scafetta goes on to say "Perhaps, stratospheric water vapor is driven by UV solar irradiance variations through ozone modulation, and works as a climate feedback to solar variation [Stuber et al., 2001]. Thus, Solomon’s finding would partially support the findings of this paper..." But Scafetta cannot describe how this might work; he can't establish any factual basis for a relationship between Solomon's findings and his thesis. In fact, he struggles to establish any physical mechanism for how the solar system vibrations might act: "Alternatively, the planets are directly influencing the Earth’s climate by modulating the orbital parameters of the Earth-Moon system and of the Earth. Orbital parameters can modulate the Earth’s angular momentum via gravitational tides and magnetic forces. Then, these orbital oscillations are amplified by the climate system through synchronization of its natural oscillators." Reading that part of Scafetta's discussion makes me better able to understand this notion of "handwaving" scientists speak of. Scafetta presents us finally with this conclusion: "...climate models are missing fundamental mechanisms that have their physical origin and ultimate justification in astronomical phenomena, and in interplanetary and solar-planetary interaction physics." A bold claim based on what appear preliminary results and an incomplete investigation, and when I consider that Scafetta tries to shore up this assertion with incorrect summaries of the IPCC thesis and what appear to be rhetorical artifices I'm left to wonder, is this research, or axe-grinding? I would have thought that before making such a claim Scafetta would have extended this work by further investigating the specific nature of the physical mechanisms that might exert the influences on climate he alludes to but cannot actually identify. Scafetta's leapfrogging of open and unexplored investigative alleys to jump to conclusions about the validity of GCM projections leaves me with the solid impression he's not concerned so much with research but instead is pursuing an agenda not primarily concerned with scientific investigation. -
HumanityRules at 04:19 AM on 20 June 2010Astronomical cycles
#66 Marcus Riccardo's article suggests Scaffetta links this analysis to the motions of the planets. It isn't just some free floating "statistical gymnastics" it does try to base things in a real universe. -
owl905 at 04:14 AM on 20 June 2010Astronomical cycles
Ken Lambert wrote:- "this “nice AGW trend” is not looking so nice when the purported energy flux imbalances are not showing up in OHC for the last 6 years and probably not much in the last 16 years." Well, they have been and they are showing up. The Scaffetti paper is similar to the 'cooling trend' distraction - statistical construction artifacts. Mathmagic, if you like. http://www.noaanews.noaa.gov/stories2010/20100615_globalstats.html 1. May 2010 - warmest May in the records, 1st on land, 2nd for SST 2. April 2010 - warmest April in the records, 3rd on land, 1st for SST 3. March 2010 - 2nd warmest March in the records, 1st on land, 13th for SST 4. March-May qtr - warmest in the records, 1st on land, 2nd for SST The cooling 'trend' only lasted as long as the latest La Nina 'event'. -
HumanityRules at 04:03 AM on 20 June 2010Astronomical cycles
60 Marcus I know the human eye likes to see patterns in things but do you not see phases of warming/cooling/warming/cooling/warming with an approximate length of 30years? We can argue about the exact length or whether that pattern in 'dirtied' by other phenomenon but if I see it and you don't then I guess there is no possibility for us to come to any sort of understanding. My comments here don't come from any sort of position other than I see that pattern superimposed on a general warming trend and I'm curious about it. I can accept that pattern may be circumstantial but I've yet to see anything that proves that. I wonder if you'd like to expand on what "people like yourself" are? Or maybe apologize for the unnecessary language in your post. Finally I don't understand who humanity should be seeking absolution from, who's judging us? -
Marcus at 03:48 AM on 20 June 2010Astronomical cycles
HR @ 63. There's a very simple test you can do-plot the temperature anomaly for 1950-2010 vs CO2 concentration for 1950-2010. Guess what you get? A linear correlation with an R-squared value of around 0.79. That effectively means that 79% of all climate variability since 1950 can be attributed *solely* to the change in CO2 concentration. In science, that's considered an extremely good fit-good enough for the statement that "CO2 is driving climate variability post-1950" to be valid. Of course correlation alone doesn't prove anything, it's also backed up by things like our knowledge of the IR-absorbtion properties of the various GHG's, the reduction in outgoing IR radiation reaching the outer atmosphere & the cooling of the stratosphere-all of which are consistent with a GHG-induced, not solar induced, warming trend. -
HumanityRules at 03:41 AM on 20 June 2010Astronomical cycles
Ooops you provide a possibly example of what I'm asking for from Lean
except what she seems to do is develop a model which has reasonable match to HADCRUT then derive the anthropogenic signal from that model. Unfortunately graph a) isn't the clearest but her model does seem to flatten out the 20th century data. The magnitude of the 1910 low and the 1940 high are reduced. We seem to have a similar problem to Scaffetta. In the case of Lean a model that seems to remove the cyclical nature of the 20th century temperature ends up 'proving' there is no room in the data for a 60year cycle.
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Marcus at 03:38 AM on 20 June 2010Astronomical cycles
HumanityRules, why are you choosing such arbitrary dates to prove your point about temperature trends? It sounds to me that, like Scafetta, you're desperate to shoehorn the data to fit your extremely weak hypothesis-yet your dates don't even fit his 60 year cycle hypothesis-they're more like 70 years here & 50 years there-hardly very scientific. Also, if you look at the HadCrut3 data, the period from 2000-2009 showed a *warming* of +0.003 degrees per year, not much lower than the warming of 1850-1880, that you're trying to attribute to this magic 60-year cycle (which isn't *really* 60 years at all). So already your hypothesis is looking extremely shaky. Also, if you look at the GISStemp data, your hypothesis takes another battering, because the cooling from 1880-1920 is missing-temperatures remained effectively *flat* during that time period. As I said above, if you look at a *real* set of 60-year cycles (1890-1950 vs 1950-2010), you see that you have half the warming in the first 60 years that you have in the 2nd 60 years-even though the first 60 years is dominated by rising sunspot numbers, wheras the 2nd 60 years is dominated by falling sunspot numbers. This does really shot some massive holes in the 60-year cycle hypothesis, as does the lack of stratospheric warming-which we'd definitely see if the sun was to blame for post 1970's warming. Lastly, the Hue & Cry of the Denialosphere has always been that correlation doesn't equal causation, yet people like yourself, HR, are pretty desperate to cling to correlations based entirely around statistical gymnastics-without any firm rationale with which to back it up. That's not the action of a SKEPTIC, its much more of a FAITH BASED position. I guess though, HR, that you'll cling to any hypothesis, no matter how far fetched, if it will absolve humanity of responsibility for global warming! -
HumanityRules at 03:12 AM on 20 June 2010Astronomical cycles
60 Riccardo But you seem to be finding a solution. The solution being there is no 60yr cycle? From yours and others post on this subject there seems a very simple solution to all this. You take the HADCUT temp record and you subtract the solar cycle effect the enso signals the volcano signals any other signals you think acceptable and you're left with a nice curve that has some simple relationship to the increases in GHG emissions. You then get the equation for your 20th century trend. Why haven't I seen this curve? It seems the consensus around climate science would tell us we know everything necessary to have a reasonably good attempt at this. In fact it doesn't seem too much to demand this of the science. -
Riccardo at 03:05 AM on 20 June 2010Astronomical cycles
shawnhet, apparently my point was not made clear enough if commenters keep repeating the same criticism: "It's not to say that the n=4 trend has more value than the n=2, but in the end we can say that the nice cyclic behaviour seen in fig. 1 depends on the choice of the trend function." The point here is that being the presence of the cycle dependent on the (arbitrary) choice of the trend, no conclusions can be drawn "at least until we can make a proper choice of the underlying trend.". That's it. If you drop the last cycle, e.g. like with the n=4 trend, i can't see what cycle need to be explained. Would you call for a connection with the 60 years sun cycle when you have less than 2 periods that does not repeat? I think the really hard part would be to explain why the supposed cycle has disappeared. -
shawnhet at 02:40 AM on 20 June 2010Astronomical cycles
Riccardo, I agree with BP on this one. Simply because Scafetta doesn't discuss physical mechanisms doesn't mean that a sixty-year cycle in temperatures(induced by variations in the position of the SSCM) is equally physically plausible to a quartic trend in temperatures. Practically everything we know about physics would say that it would not be possible (for example) for each doubling of the forcing to produce 16 times the temperature increase as the last doubling. Further, even if you accept the quartic trend, you still have the same basic patterns of the last 150 years(that match up reasonably well with changes in the SSCM) as shown by Fig. 3, except that they break down on the most recent timescales for an exponent of n=4. You are then in a position of still having to explain the apparently cyclical changes in temps. Cheers, :) -
Riccardo at 02:03 AM on 20 June 2010Astronomical cycles
HumanityRules, I'm not a scientist, you can not ask me to find the solution to a problem that professionals didn't solve yet ;). I agree that pointing to the weakness of Scafetta paper does not move anything forward; this means we have to rely on previous scientific litterature which tells us that other effects influence decadal variability more than the sun's 60 year cycle. You may find more on this, for example, in the Lean 2009 quoted in my previous reply to johnd. -
HumanityRules at 01:43 AM on 20 June 2010Astronomical cycles
>0.1oC should be <0.1oC -
HumanityRules at 01:37 AM on 20 June 2010Astronomical cycles
55 Riccardo You may answer this question as you did a similar question with something like "it's not my job to identify cycles" but how would one go about identifying a cycle in the 20th century temperature record in a credible way? Because simply saying Scaffetta's assumption could easily be wrong really doesn't move things forward. Given the complex,chaotic, poorly measured and poorly understood nature of climate I imagine most analyses of data in this field rely on one or two untested or unproven assumptions. We end up with an arguement that you can use statistics to prove anything, not the most enlightening idea. You're still avoiding specifically describing what is going on in the ~30year up and down phases of the HADCRUT3 data. I'm not convinced ENSO, Volcano and solar really address this. 56 johnd From memory earlier articles here about solar cycles, whatever the index, have tended to downplay the potential amplitude of warming that can be caused by these solar changes. Again from memory this was in the region of >0.1oC. Also this website has argued there is no long term trend in ENSO, I think you'll have to look elsewhere for an explanation. -
Riccardo at 01:24 AM on 20 June 2010Astronomical cycles
johnd, actually the ENSO periodogram is a bit messy (part B on the right taken from Lean 2009), but it does not show any dominant 60 year cycle. The large peaks beyond beyond 1000 months are spurious, being too similar to the time range of the data. Interestingly, although in Lean 2010 she also finds a peak around 60 years in the temperature periodogram, she is able to reconstruct temperature as a combination of various effects (sun, ENSO, volcanoes and anthropogenic) with no dominant 60 years cycle. Including the known sources of variability and calculating the residuals could be a good way to isolate what's left. -
canbanjo at 00:58 AM on 20 June 2010Andrew Bolt distorts again
This is a good site: http://www.eecg.utoronto.ca/~prall/climate/index.html including: http://www.eecg.utoronto.ca/~prall/climate/climate_authors_table.html -
johnd at 23:36 PM on 19 June 2010Astronomical cycles
HumanityRules at 19:27 PM, even though each individual ENSO event is short lived, the frequency at which they occur, and their magnitude, tends to cycle through periods of greater frequency, and periods of lesser frequency. With the solar cycles, is it the aa geomagnetic index that perhaps should be considered for contribution to a regular cycle? -
Riccardo at 22:48 PM on 19 June 2010Astronomical cycles
HumanityRules, the 60 year cycle in the temperature record should not be taken for granted, it's what we are looking for. So, the choice of the trend cannot be that which shows it; and you can not say that n=1 or 4 are not good choices just because they do not show the cycle. Just for clarity, I do not "wish" there isn't a cycle as you insinuate. My wishes, as well as yours, are (supposed to be) irrelevant here. I just showed that the analisys provided by Scafetta does not allow him or anyone else to claim there is this cycle, let alone that anthropogenic warming after the '70s has been exagerated. -
chris1204 at 21:51 PM on 19 June 2010Peer review vs commercials and spam
Steven Sullivan @ 52 Unless PLoS Medicine behaves much differently from the PLoS journals I know about, the Ioannidis article itself was peer-reviewed. And therefore...most likely false? The old chestnut: The statement on the other side of the paper is true & The statement on the other side of the paper is false. Actually, the PLoS Medicine article simply highlights the pitfalls of even rigorous statistical approaches and good scientific method conducted in good faith. Publication bias is also a problem - few authors ever strive to publish negative findings which languish between the dusty covers of someone's long forgotten thesis (I ought to know - I sent a torpedo in the sides of my erstwhile supervisor's then pet theory way back in 1979). However, I don't think the world of science has been impoverished by the non-publication of my work. This can be corrosive, however, when looking at effectiveness of treatment interventions and drug trials. One attempt to address this bias is the Cochrane set up for registration of clinical trials to prevent negative findings from being buried. I don't know if any equivalent exists in the physical sciences. However, I recall a suggestion that we ought to have 'A Journal of Negative Findings' which could be quite illuminating and reminiscent of the IgNobel Prizes for Research That Ought Not To Have Been Done Or Repeated. -
HumanityRules at 19:27 PM on 19 June 2010Astronomical cycles
#37 Riccardo Obviously the volcanic input is random, short-lived and wouldn't contribute to a regular cycle. Surely they would just add noise to the analysis? Again each ENSO event is random and short-lived and couldn't contribute to a regular 60 year cycle. So we seem to be left with just denying the 60 year cycle exists. Ithink the solar cycle is much shorter and my understanding is that the AGW theory only allows for a very low amplitude, nothing like the amplitude seen in the phases of HADCRUT3. I still see 1850-1880 an upward phase 1880-1920 a downward phase 1920-1940 an upward phase 1940-1970 a downward phase 1970-2000 a upward phase You could even see 2000 onwards as the turning to a downward (it's generally been flat) Obvious the noise caused by ENSO and volcano's is in there (you can see the volcaic activity of the mid-60s causing a blip upwards in the middle of the down stroke). It is a shame that Scaffetta didn't try 'cleaning up' the signal by removing these short-lived affects. I still think you identified short-lived processes that just dirty the analysis, they are not explanations of the longer phases. Just on your analysis. There is either a cycle or there isn't. You seem to wish there isn't. If the cycle exists and it is influenced by the regular movements in our solar system then surely you would expect the amplitude of those cycles to be fairly regular as well. It would seem only right to attempt to detrend to give such regular amplitudes. This may in fact be a self proving process but it seems in appropriate in your example to choose n=1 and n=4 for the very reason these give very irregular amplitudes. -
Glenn Tamblyn at 18:30 PM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Having spent some time over at Jo Nova's site trying to rebut at least some of the more outlandish claims, I can tell you it is a very frustrating experience. But here afficionado's lap it up. For example, SHB 1 doesn't 'get' the hotspot, doesn't get how wind shear could actually be a valid method. Why can't you just rely on the thermometers. Then in SHB 2, she rolls out A Watts and the SurfaceStations.org stuff. We can't trust the thermometers because of site specific influences. But we should trust the thermometers on the radiosondes. No site specific influences there.. Then the real howler. Right there on the graphs of the missing or not hotspot is another signature of AGW - Stratospheric Cooling. No comment on that one. Also we have the deep historical record of CO2 vs Temps, 500 MYrs worth and NO CORRELATION. Apart from the lack of mention of long term solar output changes. David Archibalds Bar Chart of Temp vs CO2 per 20 ppm and there 'isn't much effect left'. Without connecting the dots... Solar Increase with time explains the deep historical record when CO2 was MUCH higher...Therefore, more CO2 obviously does have an affect for many doublings to come. Jo argues that the debate is about the magnitude of feedbacks and climate sensitivity, which it is. But her 'handbooks' drag in a lot of old tired denialist rubbish arguments as well. Sceptics Handbooks they ain't. Denialist recruiting manuals? well... Be careful John. Take on Jo and some of her followers will probably come calling. Or she will probably call you all sorts of bad names. Just ask Andrew Glickson or Stephan Lewandowsky. On another note, relating to finding the hotspot, and also an analysis of the satellite data, particularly UAH, this paper is interesting. http://www.ncdc.noaa.gov/oa/climate/research/nature02524-UW-MSU.pdf By Fu et al, written a year or so after the major discrepancy between the satellite and surface data was resolved in the early naughties. They argue that the T2 temperature record from the satellite data, the troposphere, is prone to 'contamination' from part of the temperature reported being due in part to the lower stratosphere. With startospheric cooling, this may be biasing temp records for the troposphere down. They are critical of the T2LT series from UAH which is often used by sceptics. This was produced to try and compensate for the 'bleed' from the stratospheric data and they feel the methods used are not reliable. They present an alternate strategy, using Radiosonde data to try and get a temperature profile vertically and use this to produce a weighted combination of T2 (troposphere) data less some of the T4 (lower stratosphere) data to factor out the stratospheric cooling effect. They then apply this to both UAH & RSS series, producing an adjusted set of trends. The interesting item to note is Fig 3. Their adjusted trend for the RSS data shows a clear difference between the Surface and the Troposphere for both Tropics & Southern Hemisphere. There is the 'hotspot'. -
iskepticaluser at 16:43 PM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Re the limits of scientific certainty, a recent essay in the Economist (copy here) had an interesting take on how different audiences weigh evidence: “In any complex scientific picture of the world there will be gaps, misperceptions and mistakes. Whether your impression is dominated by the whole or the holes will depend on your attitude to the project at hand. You might say that some see a jigsaw where others see a house of cards. [Climate scientists] have in mind an overall picture and are open to bits being taken out, moved around or abandoned should they not fit. Those who see houses of cards [deniers] think that if any piece is removed, the whole lot falls down.” -
kdkd at 15:59 PM on 19 June 2010How climate skeptics mislead
BP #217Also, perceiving (pictures) and understanding (propositions) are two very different human abilities. Critical thinking is only possible in the latter domain.
This looks like a logically fallacious argument (e.g. you're indirectly claiming we are unable to critically reflect on art, which is fundamentally a perception based activity). Lots of scientific and quasi-scientific disciplines require critical reflection on perception. How on earth do you think that a problem space is defined in the first place! Anyway, the fact that you have to perform such logical contortions to defend your argument is interesting, as it gives us a way to critically reflect on the validity of your position. -
Chris Colose at 14:09 PM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
By the way, another community very interested in this "hotspot" stuff is the hurricane people, since hurricane strength is a function of SST and the upper level outflow areas. One issue brought up in the recent RealClimate article (in the comments) was stratospheric cooling and its influence on the uptick of tropical cyclones. Similarly, studies have pointed out that you can get more storms by reducing the moist stability of the atmosphere (i.e., by getting rid of the amplification in the upper atmosphere.) See e.g., T. R. Knutson, J. J. Sirutis, S.T. Garner, G. A,. Vecchi, and I. M. Held, 2008: Simulated reduction in Atlantic hurricane frequency under twenty-first century warming conditions, Nature Geosciences, doi:10.1038/ngeo202 -
Marcus at 13:56 PM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Gary-to say that anything in science is 100% certain is to betray an ignorance of science. If we only accepted those things we were 100% certain of, then we'd still be living in the Dark Ages! I've worked as a scientist for some 15 years now, in a number of non-controversial fields, & I've yet to come across any where our body of knowledge was based on 100% certainty-or even 90%. Yet this *only* seems to be an issue in Climate Science-WHY?!?! The inability to detect a Tropospheric Hot Spot doesn't-by itself-negate the existence of AGW because, as John & Chris have rightly pointed out, this Hot Spot is supposed to exist independent of Global Warming. So our inability to detect it could simply be the result of (a) an incomplete understanding of how this effect responds to a warming climate or (b) a lack of instruments sensitive enough to detect it. Even if the Tropospheric Hot Spot is proven to *not* exist (as unlikely as that might seem), we'd still have more than 100 years of knowledge about how certain gases contribute to the planet's natural energy balance-& how they might contribute to an energy *imbalance*-combined with a strong correlation between near-surface/tropospheric warming & rising CO2-in the absence of rising solar activity; the reduction in detectable outgoing IR radiation & the cooling of the stratosphere. All of which are very consistent with an enhanced Greenhouse Effect being the most likely contributor to global warming over the past 60 years. What Jo Nova-& yourself-are promoting is what is referred to as "manufactured uncertainty"-which is directly antithetical to scientific endeavor IMO. -
Chris Colose at 13:43 PM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Alexandre, you are right that it's hard to imagine a strictly isothermal atmosphere, although a very weak lapse rate is important for the dynamics of the winter hemisphere in a snowball Earth, or winter-time in Mars, but the hypothetical example is only used to illustrate the importance of the vertical temperature structure of the atmosphere in general. This is useful for not only understanding the GHE but interpretation of outgoing spectra. Consider the following diagram from Petty's book (which John Cook also used here in discussing the paper I helped co-author with Halpern et al. for the G&T rebuttal):What you're seeing in the top figure is the outgoing radiation from a sensor looking down at the Earth (or looking down at 20 km, which is almost the same thing). In the atmospheric window (from about 800 to 1000 inverse centimeters, with wave number being the dimension on the x-axis) the sensor is seeing emission from the surface and lowermost atmosphere, since there is little absorption by atmospheric gases in this spectral region. Thus the emission follows relatively smoothly along the dotted Planck emission line corresponding to the warmest temperatures at the bottom of the atmosphere. In the optically thick regions, such as between 600 and 800 inverse centimeters where the CO2 has strong absorption, the emission is only being detected from the colder layers of the atmosphere. For example, the center of the CO2 band is following along the 225 K Planck emission line. Consider the case where you are situated in a region with a temperature inversion, which is a persistent feature in polar winter for example: http://www.sundogpublishing.com/fig8-3ab.pdf (it's a PDF file so I cannot readily display the image via HTML, see bottom graph for the Antarctic ice sheet). Here the temperature is increasing with height in the atmosphere. Now you're still seeing emission from the surface in the window regions. In the CO2 band the emission aloft is coming from warmer areas, and so the CO2 is actually producing somewhat of a "negative greenhouse effect." If the planet had no atmosphere with a blackbody surface you would see a smooth emission spectrum at ~255 K (assuming present-day albedo). In the typical case where the temperature declines with height, what the greenhouse gases are doing is taking a bite out the Planck spectrum, and so the total area beneath the curve is reduced, which means the planets emission is reduced. This therefore reduces the emissivity of the planet and so it must heat up until the temperature is such that the area under the Planck curve is the same as before (i.e., it balances the incoming stellar flux). This occurs because increasing the temperature of a body increases the intensity at all wave numbers and so the total area under the Planck curve increases. But in order for this "bite" to occur from the CO2 band, the sensor must be looking at emission from a different temperature than the surface. If the whole atmosphere were of uniform temperature, then the emission spectrum the sensor records would simply follow that temperature, and one could make no distinction as to whether or not the emission was coming from the surface or aloft. Since the area under the Planck curve would not change, you would not change the temperature by absorbing more of the outgoing energy. Even if the atmosphere were so optically thick that emission were coming from the uppermost layers, those layers are the surface temperature in the isothermal limit, so top-of-atmosphere radiation balance requires equilibrium with the absorbed solar energy at that temperature. By the way, there again are some exotic cases. On planets where you can get CO2 clouds or other very effective infrared scattering, you can get a greenhouse effect through IR scattering rather than through traditional absorption and re-radiation. This could produce a greenhouse effect regardless of the temperature profile. This may have been a big part of getting Early Mars above freezing. Re David Horton. Consider this image: Here we see three curves which correspond to three hypothetical and idealized temperature profiles. Lines "A" and "B" are the same slope, the only difference is the intercept of the curve, so that the absolute temperature at any height in "B" is warmer than in case "A" (Say, that planet absorbs more solar energy but has the same lapse rate). However, in a global warming situation (in the tropics) we expect the adjustment to look something more like the transition from "B" to "C." In this case, not only do you get temperature rise at the surface, but the slope of the adiabat changes in such a way as to produce amplification aloft. If you're looking for a more detailed contour plot that shows the temperature change with height and with latitude, here is a simulation for 2xCO2. http://data.giss.nasa.gov/efficacy/Rc_pj.1.06.html All of a sudden this change of slope in the adiabat becomes a feedback, because now the air at any given altitude (now at a warmer temperature) would radiate more energy to space. This partially offsets the water vapor absorbing effect. Hope that helps -
Marcus at 12:26 PM on 19 June 2010Astronomical cycles
Ken Lambert, it might surprise you to know that there are significantly large holes in the fossil record that make it extremely difficult for scientists to show how life evolved from single-cell to the current, wide array of multi-cellular organisms-so are you suggesting we abandon Evolutionary Theory in favor of Creationism? Indeed, the fields of biology, physics & chemistry consist of theories & models which lack some pieces of the puzzle to make our understanding of them complete. If we were to apply your attitude to AGW to the rest of Science, then we'd simply abandon science altogether. Whatever pieces of the AGW might be "missing", the pieces we have paint a very telling picture-we have near-surface & troposphere warming at an accelerated rate-a rate that is strongly correlated (ca. 75%) with the accelerated rate of CO2 emissions into our atmosphere; we have extensive knowledge of the various gases that contribute to the natural-& enhanced-Greenhouse Effect, most especially their ability to absorb & re-emit Long-Wave IR radiation; we have measurements of the Stratosphere showing how it has cooled at almost the same rate as the troposphere has been warming (which wouldn't be happening if the sun were to blame); of the remaining, inter-annual climate variability for the past 60 years, we can explain virtually all of it in terms of either (a) the 11-year solar cycle, (b) changes in Ocean Oscillations (most especially the El Nino/La Nino cycle & (c) changes in the atmospheric concentration of other-more potent-Greenhouse gases (most especially methane, which had been leveling off since the 1990's, but which has started to rise again recently). Now, when the skeptics can come up with a feasible model to explain the observed changes in temperature throughout our atmosphere, then maybe I'll listen to them. Scafetta's paper, though, doesn't even come close. All Scafetta does is engage in some truly Herculean levels of mathematical contortionism to make the trend fit his theory (something that the correlation between CO2 & climate variability doesn't need). -
Jim Meador at 11:51 AM on 19 June 2010Astronomical cycles
It strikes me that a lot of the recent activity by skeptics is to perform some "analysis" that looks like science from far away. The fact that real scientists can come in to close range and debunk it does not really matter to the skeptics, because thay are playing to an audience that a) is relatively unsophisticated scientifically and b) does not trust or care what "real" scientists have to say about the original work. This debate is political, not scientific. The skeptics are winning the political debate, because their side is winning converts, even though their science is bunk. I am not sure how to respond, but I think that the present situation demands new tactics, which involve more that just debunking bad skeptic science. -
David Horton at 11:41 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
I'm missing something too, or being particularly thick today. Can John and/or Chris explain why the "tropospheric hot spot" (which in itself is a funny term, shouldn't it be layer rather than spot?) should change with global warming, and how it changes (higher, stronger, thicker?) as the surface warms. The implication of the "moist adiabatic lapse rate skeptic" is that someone is doubting the process, I can (I think) understand the process, what I can't understand is how it relates to global warming. -
Alexandre at 11:09 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Chris Colose #11 I´m trying my best to grasp your explanation here and on the Climate Change blog, but my steps forward are still short. One particular issue seems to be important, and I could not understand it: why is it that the GHE depends on the lapse rate? It´s quite difficult to me to try to imagine an atmosphere without a lapse rate, but it would seem to me that this uniformly warm fluid would have downward radiation and GHE as well... What am I missing? -
Doug Bostrom at 11:05 AM on 19 June 2010How climate skeptics mislead
A friend just remarked on how prone I am to using analogies and resorting to metaphor. Indulge me please once more. The tools and techniques we have to create a "big picture" in science produce the net effect of what artists call pointillism. Tiny bits of knowledge appear on a canvas and if they are mutually consistent and compatible a picture of a large system encompassing all the colors and positions of those dots will emerge. If there are too few dots or too many appear in the incorrect position or with the incorrect color no coherent picture can be perceived. I think most of us understand our science in this manner, a way that is imperfect, even impressionistic but is still useful. Because of our personal limitation and as well as defects in our knowledge and measurement capabilities we cannot say what the exact value of a particular dot in the picture is, we cannot say that each dot is in exactly the right position, but we can nonetheless see a picture emerging from the collection of points on the canvas recording our inquiry. When I think of counter-arguments to anthropogenic climate change, my conclusion is that the picture that can emerge from the number and type of dots supplied by the very few valid research results in contradiction to the theory as well as the galaxy of frankly wrong opinions contrary to the other school is incoherent, so abstract as to convey little or no meaning. But by contrarians we are asked again and again to focus on just a single dot whether from the coherent picture on one canvas or the incoherent image on the other. -
canbanjo at 10:57 AM on 19 June 2010Andrew Bolt distorts again
Steven, I also have not made my points clearly enough. its not me that needs persuading. I am on the 'frustrated at the science communication failure' bandwagon. i would like to do something about it. -
How climate skeptics mislead
BP, perhaps our disagreement is mostly definitional. From Merriam-Webster, defintion 3a: science is "knowledge or a system of knowledge covering general truths or the operation of general laws especially as obtained and tested through scientific method" (emphasis is mine). The "general truth" part is where the "big picture" belongs. The "obtained and tested through scientific method" part is where your descriptions belong. Both are within the domain of science. This particular blog post however is about the "big picture" part. -
How climate skeptics mislead
BP >Of course the "big picture" or rather whatever picture you can put together by whatever means can have a tremendous heuristic value. But mark me, science is not about pictures. I'm not sure what you mean by that second sentence. Are you saying that a broad understanding about how things work (or as you put it, understanding the problem space) isn't a part of science? That seems like an awfully provincial definition of what science does. To what domain does the "big picture" belong to then if not science? -
Sean A at 10:22 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
"we lack the rock-solid data to prove without a shadow of a doubt one side of the argument or the other" Science never claims anything to be 100% proven. Uncertainty is always admittedly, explicitly part of the picture. Doubt about science is easy to manufacture. Is the science settled? Doubt mongering works -
Berényi Péter at 10:06 AM on 19 June 2010How climate skeptics mislead
#216 kdkd at 07:28 AM on 19 June, 2010 Failure to look at the big picture, rather inappropriately insisting that a reductionist approach is the only possible way to understand the problem space Let me humbly note I was not talking about understanding the problem space. Of course the "big picture" or rather whatever picture you can put together by whatever means can have a tremendous heuristic value. But mark me, science is not about pictures. It is about propositions. And what you call a reductionist approach is not for understanding the problem space, but for understanding specific propositions, for debugging if you wish. Logic, deductive reasoning and focus on details are invaluable tools in this quest. Also, perceiving (pictures) and understanding (propositions) are two very different human abilities. Critical thinking is only possible in the latter domain. -
Chris Colose at 09:35 AM on 19 June 2010How Jo Nova doesn't get the tropospheric hot spot
Good post. Perhaps I can shed some more light on the question by NewYorkJ in reference to my article. The lapse-rate feedback is defined as the difference between total-temperature feedback and surface-temperature feedback. It is thus a measure of how the radiative budget is perturbed by shifting the vertical thermal structure of the atmosphere. In the isothermal limit where the temperatures aloft are the same as the ground temperature, there is no greenhouse effect and the planet's emission must satisfy equality with the absorbed incoming solar flux. As the atmospheric opacity increases, the atmospheric/surface temperature gradient will increase, with the TOA/surface temperature ratio approaching zero as the atmospheric opacity approaches infinity. As the globe warms, the tropical temperature gradient between the surface and free atmosphere must decrease, and consequently, emission increase from upper layers of the atmosphere providing a negative feedback. The situation is reversed at the poles where the low-level anomalies tend to be amplified relative to the free atmosphere since water vapor is so low and surface albedo feedbacks dominate. This thus provides a local positive lapse rate feedback. If the tropics behaved analogously and the upper atmosphere was not amplified relative to the surface, then the lapse rate could only be less negative (or even positive). Note that cynicus' comment does not really make sense in this regard, because the surface can warm independently of the lapse rate. The lapse rate just sets the difference in temperatures between the surface and layers aloft, it says nothing about the absolute temperature at any point. In models however, those models with the greatest reduction in outgoing radiation from water vapor also produce the greatest enhancement of emission aloft from temperature feedback (in the tropics). This is the definition of the so-called "hotspot" and it has nothing to do with the direct increase in CO2. For those still not convinced that the lapse rate is intimately connected with water vapor (and thus the WV feedback), you can see from the following diagram that, interestingly, the uncertainty in the WV+LR feedback is actually much smaller than the uncertainties in either the WV or LR feedback considered individually.
Because of this connection it is quite common to consider the WV+LR feedback collectively. So the hotspot is indeed due to the moist adiabat, and the lack of such amplification is neither a disproof of anthropogenic global warming, nor is an argument against a high sensitivity.
In some exotic cases, it is conceivable that greenhouse gases themselves can alter the thermal structure of the atmosphere in such a way as to produce a large reduction to the greenhouse effect in condensation. This might happen for example in an atmosphere that was strongly absorbing to incoming solar radiation. If you replace radiation at incident at the surface with radiation absorbed aloft, you can generate an anti-greenhouse effect and make a deep layer that is nearly isothermal. It is thought that if the ratio of methane to CO2 concentrations approaches one, you can get a "haze layer" that absorbs solar radiation in the upper atmosphere and radiates it back to space, whilst cooling the surface. This has implications for early Earth evolution. In the modern however, water vapor does absorb some solar radiation and is dominant in the lower atmosphere where humidity is greatest and the polar regions where you have a good chance of absorbing upwelling photons from high albedo. This shortwave component of the water vapor feedback is positive by causing an increase in shortwave absorption and accounts for about 15% of the total water vapor feedback.
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Steven Sullivan at 09:28 AM on 19 June 2010Andrew Bolt distorts again
canbanjo asserts: "Clarifying what Hulme is saying is very important. It sounds like we now need to know the identities of all of the people that are 'qualified at first hand' to confirm the statement: “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations”. " Not terribly. The science doesn't change. Hulme is mainly concerned with the third of three primary questions of climate change (as noted by by Philip Kitcher in his June 4 review of recent books, including Hulme's in Science): "First is the issue of whether human activities, specifically actions that increase the emission of greenhouse gases, are contributing to a signifi cant average warming of Earth. (As all the expert authors point out very clearly, there is no suggestion that the temperature of every region will rise during the next decades.) Second are questions about the probabilities with which various phenomena (complete melting of ice sheets, for example) will occur and about their consequences for human beings and other species. Third are considerations about what might be done to halt (or even reverse) the warming and to limit the damaging consequences. Hulme emphasizes the complexity of the third set of issues" I think the main lessons of this incident are for Hulme -- think about how your words may be (mis)used -- and the 'denial' community -- be careful what bandwagon you leap on. -
Riccardo at 08:20 AM on 19 June 2010Astronomical cycles
Berényi Péter, I do not trust Scafetta exponent 2 nor any other, as clearly stated, so it's not at all my job to play with it. My "job" has been to show that we can not extract valuable informations from this kind of analysis and that the strong conclusions of that paper lack solid bases (euphemism?). P.S. You used a different functional form from Scafetta (and me) and dropped part of the data, no surprise you got different results. This confirms, once more, my point. -
kdkd at 07:42 AM on 19 June 2010Astronomical cycles
BP #49 And that analysis is basically meaningless without some kind of regression analysis. The only way to attribute causality via regression is inductively, by looking at how the error component of the model changes with inclusion and exclusion of various parameters. This helps us to understand the behaviour of the system. My crude statistical analysis of climate data using these kinds of techniques clearly showed that there would have to be evidence of unprecedented quality if CO2 was not to be the main and increasing driver of the current increases in global termperature. -
Berényi Péter at 07:34 AM on 19 June 2010Astronomical cycles
#44 Riccardo at 21:38 PM on 18 June, 2010 naively looking at radiative forcings as you did reinforced my findings, if anything I am surprised. Just try the following. As we do not know the correct exponent, look for the best fit using the form a×tξ-b, where ξ is also to be found. If you do it for the 160 years between 1850 and 2009, 3.35 (not 4) will be the optimal exponent. However, it is not because the actual trend is accelerating so fast, but because the 60 years long dominant cycle fits 2+2/3 times to this timespan. If you choose an integer multiple of 60, like 1890-2009, the optimal exponent is 1.82. On the other hand if you try to fit the expression to a simple 160 years long sinusoid with a 60 year period, you may get extremely large exponents (depending on phase). Therefore the source of the apparent super-quadratic trend is the cyclic component, not secular change of forcing. On top of that the acceleration computed this way seems to diminish with time. 1850-1969 2.69 1855-1974 2.29 1860-1979 2.13 1865-1984 2.28 1870-1989 2.11 1875-1994 2.02 1880-1999 1.97 1885-2004 1.99 1890-2009 1.82 It's not physics, just plain data analysis. Of course it could be done somewhat more correctly with joint least square fitting of trend and sinusoids, but it is a job for you or Scafetta. -
kdkd at 07:28 AM on 19 June 2010How climate skeptics mislead
This thread is very interesting. And with BP being one of the most prominent so called sceptics on this site, he's given us a lot of interesting information about his approach. The fundamental issues seem to be:- No understanding or acknowledgeement of the fundamental difference between scientific problems and engineering/mathematical/logical problems
- Related: misapplication of logic, with some confusion between what is an inductive approach and a deductive approach. As well as the inappropriate of the logical inverse where convenient (e.g. #215)
- Failure to look at the big picture, rather inappropriately insisting that a reductionist approach is the only possible way to understand the problem space. It's pretty well established that in the non experimental sciences where complexity is a significant component, that reductionism will not result in a comprehensive explanation
- Weighting evidence based on how it is perceived to bring the evidence for AGW into doubt, rather than on its quality, or the provenance of the source
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How climate skeptics mislead
BP, No, I do not want you to prove it. Where did you see that? Disprove, that's what you need to do Sorry, you're right I mispoke. What you suggest is that we take your hypothesis as true until we can disprove it. I maintain that that is a silly approach.
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