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Comments 129551 to 129600:

129551. chris at 07:14 AM on 24 October 2008
        Is Antarctic ice melting or growing?
        Re #15 Monaghan and Bromwich seems to me to be essentially confirmatory in relation to our understanding of the Antarctic and the implications of a warming world. They point out that while the Southern oceans have warmed significantly in the last few decades, that this hasn't resulted (as far as we can tell) in enhanced snow deposition. They suggest that a predicted 2-3.5 oC of Antarctic warming in the current century might yield a 10-20% increase in snowfall, with a potential mitigating effect on sea level rise. However it's not clear (to me anyway!) whether this relates to NET Antarctic mass. After all, a 2-3.5 oC temp rise in the Antarctic (there hasn't been much overall warming there so far, much as models predicted) might be expected to yield significant melt at the continental margins (as we're seeing in Greenland), which might or might not balance or overpower excess snow deposition... There's a certain extent to which this is somewhat academic. Other than the expected mass loss in the Antarctic peninsula and to a lesser extent in the West Antarctic ice sheet, significant Antarctic ice mass loss hasn't been much factored into the consequences of global warming. As predicted by models from 20 years or so ago (see post #66 in the "Arctic sea ice - natural or man-made" thread: http://www.skepticalscience.com/Arctic-sea-ice-melt-natural-or-man-made.html ..Antarctica is partly insulated from the effects of global warming largely due to the peculiar ocean currents in the deep Southern latitudes, and the very efficient transfer of thermal energy to the high Northern latitudes. So the concerns (in relation to sea level rise) in a warming world relate largely to Greenland. No one expects Antarctica to melt significantly. Monaghan and Bromwich is consistent with that expectation. I'd still like to know whether they consider that their modelling of enhanced snow fall through the latter parts of the 21st century, due to enhanced Antarctic temperatures in a world warming under the influence of enhanced greenhouse gases, is a NET contribution to sea levels, or is independent of any warming-induced contribution to sea level rise from enhanced melt at the low altitude continental margins. I get the impression from their paper that they haven't considered the latter....that's not what their paper is about....
129552. Quietman at 04:55 AM on 24 October 2008
        Volcanoes emit more CO2 than humans
        Patrick In a new article at MSNBC titled ‘Dead’ planets might be livable after all they explain planetary tidal forces in the manner that I see them (inferring from the Solar Jerk) but carried to more of an extreme than we experience. The hypothesis is the same however, it's only a matter of degree.
129553. Dan Pangburn at 18:58 PM on 23 October 2008
        Models are unreliable
        It was somewhat surprising to discover that the study of climate science does not require any exposure to the ‘theory’ (it is widely and successfully applied practice in some engineering disciplines, especially electrical, mechanical and aeronautical) of dynamic systems with feedback control. Their ignorance has resulted in climatologists coming up with their own expression for feedback and the perception that feedback in climate is somehow different from feedback in other systems. In effect it isn’t (for more, see 49 above). Earth’s climate is a dynamic system that is controlled by NET feedback. A lack of understanding of dynamic systems with feedback and how they work has resulted in many articles being published that a reviewer who was knowledgeable in dynamic systems with feedback would quickly recognize as patently false. Climate publications are staffed by climate scientists. Articles for publication in climate publications are peer reviewed by climate scientists. None of them appear to be knowledgeable in dynamic systems with feedback and thus they are unable to recognize information that is readily shown to be false and should never have been published. Feedback means that the output (results, response) influences the input. Feedback can be positive or negative. Positive feedback means that the output is greater than it would be without feedback. Negative feedback means that the output is reduced from what it would be without feedback. Net feedback is the effective feedback when there are both positive and negative feedbacks. If net feedback is positive the trend must continue up at a progressive rate. The effect on a savings account balance with compound interest is a familiar example of net positive feedback. Complexity does not alter how net feedback works. Now look at any credible historic temperature data. To be credible, a temperature trace must be for a long enough time to average out cyclic variation from random noise and other factors such as ENSO. The temperature trace does not even need to be correct in absolute terms just reasonably valid in relative terms time-wise. It should also be substantially longer than any smoothing period that was employed in generating the data set. A temperature trend can not change direction from up to down if net positive feedback exists. If there is at least one change of average global temperature trend from up to down (a down trend of average global temperature can not exist with net positive feedback) without an overpowering external influence, it proves that net positive feedback does not exist. There are many and there are downtrends. Therefore net positive feedback does not exist. Without net positive feedback the climate computer models (GCMs) do not predict significant global warming from increased atmospheric carbon dioxide. There are other issues with GCMs and their use as described at 32 above. Climate scientists and climate scientist wannabes who claim that ‘the science says’ are simply ignorant of an important part of science that is relevant to the issue. Climate scientists, in their ignorance, impose net positive feedback on their GCMs which causes them to falsely predict that added atmospheric carbon dioxide causes significant global warming.
129554. DB2 at 06:50 AM on 23 October 2008
        Is Antarctic ice melting or growing?
        A 2008 paper by Monaghan and Bromwich takes a different approach to the Antarctica question. http://polarmet.mps.ohio-state.edu/monaghan/papers/monaghan_bams_7747.pdf They look at 50 years of temperature and snowfall records for the continent. With temperatures they note that "In contrast to widespread temperature increases globally, instrumental records indicate statistically insignificant (p>0.05*) seasonal and annual near-surface temperature changes over continental Antarctica from the late 1950s through 2000." Snowfall data has larger uncertainties and cyclical changes, but they write "there has been little overall change in Antarctic snowfall during the past 5 decades" When looked at on decadal time scales, atmospheric models indicate that snowfall over Antarctica could possibly rise by as much as 5% for each 1°C increase in temperature. The researchers write that "if global climate model projections of 2-3.5°C temperature increases over Antarctica by the end of this century are accurate a ~10%-20% increase in snowfall might be expected if the 1960-2004 sensitivity relationship holds." And in this regard, they note that "a 15% increase of Antarctic snowfall would mitigate an additional ~1 mm per year of global sea level in 2100 compared to today."
129555. chris at 06:37 AM on 23 October 2008
        CO2 lags temperature
        Really Quietman? What specific ("more recent..") evidence informs your opinion that the greenhouse effect doesn't supplement the Earth's global temperature such that we are around 30 oC warmer than we would otherwise be without the greenhouse effect (taking into account the variations I pointed out in 14 and positions of the continents and that sort of thing)? Which specific concepts that were "assumed it to be correct" are now "also incorrect"? In what manner specifically does the determinations "more recently" "point in the wrong direction"? Please be specific.
129556. chris at 05:26 AM on 23 October 2008
        Ice age predicted in the 70s
        Re #3: It's easy to be misled by the titles of papers. The examples you've asserted as supporting a 1970's perspective of global cooling don't actually do so. Your second article sounds like it does: Convection in the Antarctic Ice Sheet Leading to a Surge of the Ice Sheet and Possibly to a New Ice Age T. Hughes, Science Vol. 170. no. 3958, pp. 630 - 633 (1970) But it's just a potentially misleadingly worded title. If you read the paper it's got zero relevance to a possibility of a "new ice age" in the near (i.e. "near" from a 1970 perspective). It's about the GENERAL nature of ice Antarctic ice sheet advance that might (within a particular "surge" theory) be linked to the glacial cycles within the Pleistocene. So it's about how glacial periods might in general occur. That's very clear from reading the paper. It's also evident just from reading the abstract: abstract: "The Antarctic surge theory of Pleistocene glaciation is reexamined in the context of thermal convection theory applied to the Antarctic ice sheet. The ice sheet surges when a water layer at the base of the ice sheet reaches the edge of the ice sheet over broad fronts and has a thickness sufficient to drown the projections from the bed that most strongly hinder basal ice flow. Frictional heat from convection flow promotes basal melting, and, as the ice sheet grows to the continental shelf of Antarctica, a surge of the ice sheet appears likely." So it's a theoretical study of a mechanism for ice sheet advance during glacial cycles. It doesn't address the possibility of any such event during the current Holocene, and has nothing to do with 1970's scientific perception of global warming or cooling or any such thing. Likewise it's understandable why Peterson et al. didn't include your other paper as a "cooling"/Ice Age" one: Return of the ice age and drought in peninsular Florida? Joseph M. Moran, Geology 3 (12): 695-696 (1975) Although the title (and the rather odd abstract) might suggest that the paper is about the "return of the ice age", the question mark highlights the fact that the author is rather equivocal over such a conclusion. Here's how he ends his (very brief) note: "While there is an interesting parallel between recent and late-glacial events in the tropics, no clear cause-effect relation has been established between the current hemispheric cooling trend and precipitation trend in peninsular Florida. Also, even if a linkage were established, there is no certainty that the hemispheric cooling trend will not reverse itself in a few years. Rather than portraying a bleak future for Florida’s water supply, therefore, the observations presented here should serve as stimuli for further monitoring and research to promote understanding of the controlling atmospheric phenomena." In other words, the paper relates to precipitation trends with potential implications for water supply in Florida, and the author indicates that there isn't any necessary relation between cooling and precipitation trends and indicates anyway that the cooling trend might reverse itself. So neither of your suggestions - absolutely not the first one which is totally irrelevant to 1970's perspective on cooling/warming or otherwise, - nor the second one can be taken to support the notion of any 1970's scientific perception of global cooling (by the criterion that Paterson et al. set of a paper with a clear projection of climate change or discussing an aspect of climate forcing relevant to time scales of decades or centuries). Morgan's short note doesn't come to any conclusion - the "cooling" "...might reverse itself in a few years".
129557. Quietman at 03:10 AM on 23 October 2008
        Arctic sea ice melt - natural or man-made?
        Patrick Re: Ozone - Agreed Somewhere here there are links to papers on ozone that agree with what you said (I don't remember where).
129558. Patrick 027 at 15:47 PM on 22 October 2008
        Arctic sea ice melt - natural or man-made?
        ... But also: ozone chemical reactions will be affected by temperature. Temperature affects circulation. Ozone affects temperature. Circulation affects temperature and ozone. The enhanced warming at low levels in high latitudes, is strongest in the colder months, and might actually be reversed (reduced warming relative to some other latitudes, at least over water (?)) in some portion of the summer or near that time.
129559. Patrick 027 at 15:37 PM on 22 October 2008
        Arctic sea ice melt - natural or man-made?
        10. Some thoughts: Temperature changes at the surface and lower troposphere will have a radiative effect on the stratosphere. Especially when any intevening clouds or high water vapor concentrations are close enough to the surface, there will be a band of wavelengths in which the surface radiates up to the ozone layer. Since the high latitudes (northern hemisphere) warm more than the low latitudes, this will tend to warm the northern polar stratosphere more. However, the latitudinal trend is reversed in the upper troposphere, which will substitute radiation from below with it's own, to varying degrees, depending on wavelength, cloud top heights, etc. Yet, to begin with, I think the latitudinal trend is greater at lower than upper levels, and the increased greenhouse effect will shield the stratosphere more from the surface, and this would tend to warm the polar stratosphere more than the lower latitude stratosphere.** Increased solar UV should produce more ozone. Higher ozone concentrations would push the distribution of solar heating upward a bit. Relative to the local vertical distribution of ozone, solar heating (by UV) will be more concentrated toward higher levels at higher latitudes and in winter, because of the angle of the sun's rays (a longer path length fitting into the same vertical distance).
129560. chris at 22:57 PM on 21 October 2008
        Climate sensitivity is low
        re #25: I forget to give the url to Schwartz's reassessment/correction of his original work: http://www.ecd.bnl.gov/steve/pubs/HeatCapCommentResponse.pdf
129561. chris at 22:55 PM on 21 October 2008
        Climate sensitivity is low
        It's worth pointing out that Stephen Schwartz has recognised some of the essential errors in is analysis (see John Cook's top article and also my post #5), and has issued a correction in relation to the original analysis that everyone got very excited about. Now Schwartz considers that his analysis (still a rather weak approach - see Tom Cook's top post and my post #5), yields a climate sensitivity of 1.9 +/- 1.0 oC per doubling of atmospheric CO2. That's within the range of all the pukka science out there (a climate sensitivity near 3 oC +/- a bit), and if Schwartz were to relax his (rather arbitrarily determined) time constant for the earth's inertial respense to forcings a bit more, then he'd be smack on the value that everyone else gets. So another storm in a teacup! Sadly, while Schwartz's original paper was flashed all over the blogosphere, we can be pretty sure that Schwartz's reassessment will be left unmentioned... ..but not here!
129562. Patrick 027 at 14:30 PM on 21 October 2008
        Arctic sea ice melt - natural or man-made?
        Re Quietman 4 (links): 10. "Evidence mounts for Arctic Oscillation's impact on northern climate" http://www.washington.edu/newsroom/news/1999archive/12-99archive/k121699.html "The Arctic Oscillation is a seesaw pattern in which atmospheric pressure at polar and middle latitudes fluctuates between positive and negative phases. The negative phase brings higher-than-normal pressure over the polar region and lower-than-normal pressure at about 45 degrees north latitude. The positive phase brings the opposite conditions, steering ocean storms farther north and bringing wetter weather to Alaska, Scotland and Scandinavia and drier conditions to areas such as California, Spain and the Middle East. In recent years the Arctic Oscillation has been mostly in its positive phase, research has shown. "In its positive phase," Thompson said, "frigid winter air doesn't plunge as far south into North America," meaning warmer winters for much of the United States east of the Rocky Mountains, while areas such as Greenland and Newfoundland tend to be colder than normal." ... "Stratosphere cooling in the last few decades has caused the counterclockwise circulation around the North Pole to strengthen in winter. In turn, the belt of westerly winds at the surface along 45 degrees north latitude has shifted farther north, the scientists said, sweeping larger quantities of mild ocean air across Scandinavia and Russia and bringing balmier winters over most of the United States as well." The Arctic Oscillation is an alternate view of what many scientists call the North Atlantic Oscillation, the researchers said. Year-to-year fluctuations in the North Atlantic Oscillation are thought to be prompted primarily by changes in the ocean, as with El Niño. However, Wallace, Thompson and Baldwin argue that the North Atlantic Oscillation is in fact part of the Arctic Oscillation, which involves atmospheric circulation in the entire hemisphere. They say the trend toward a stronger, tighter circulation around the North Pole could be triggered just as well by processes in the stratosphere as by those in the ocean. The trend in the Arctic Oscillation, they said, has been reproduced in climate models with increasing concentrations of greenhouse gases." Very interesting. Presumably solar and volcanic forcings, etc. would also have effects on stratospheric temperatures and thus could also affect stratospheric-tropospheric interactions. I've read that current (AO)GCMs (computer climate models) don't resolve or have trouble resolving some circulation processes of the upper atmosphere. However there is no reason to suspect that increased knowledge about this will lead to a conclusion that significantly reduces anthropogenic forcings' roles relative to other things. (It sounds like, perhaps, the changes in tropospheric circulation associated with AO (?) (Arctic Oscillation - same as NAM? - North(ern ...) Annular Mode ?) rearrange heat but don't directly result in a change in global average temperature by that - except of course, there could/will be feedbacks which might have some global average tendency one way or the other.) I'll have to look more into this. But a few quick notes for now: Increased/decreased horizontal temperature gradients increase/decrease vertical geostrophic wind shear - wind speed above increases/decrease or wind speed below does the opposite or both. Geostrophic winds in the stratosphere (and mesosphere, etc.) is affected by tropospheric conditions, and vice versa, as it is for parts of these. Wind direction is also potentially affected. Vertical motion can transport momentum. Perhaps less obviously but more importantly (?), interactions among various layers can transfer momentum vertically (vertical wind shear allows air to move into different conditions (as determined by the changing quality of air above and below) requiring it to accelerate in some way; the layers interact). Vertical interaction is generally reduced (at least for transient disturbances?) when stratification (vertical static stability) is greater - when temperature decreases with height less or increases with height more. (Imagine how much more intensive the mechanical interaction of ocean and atmosphere would be if the ocean were only 0.1 % of it's density.) 3. "Arctic Climate" http://nsidc.org/arcticmet/basics/arctic_climate.html "extreme solar radiation conditions" - This just refers to the seasonal extremes of insolation (At the pole, 6 months of darkness, 6 months of daylight with low sun angle, etc.).
129563. Patrick 027 at 11:06 AM on 21 October 2008
        Arctic sea ice melt - natural or man-made?
        0.2 - models This is only tangentially related, but it has been argued that evidence exists for solar forcing on other planets. This isn't a very strong argument. What's ironic is - from the little I've read about it - the argument that Jupiter's climate is changing - it's ironic because the changes that have occured seem to be a form of internal variability, and may have been predicted by a computer model! (Now I'm going to another part of this website to double check that.)
129564. Quietman at 02:26 AM on 21 October 2008
        Arctic sea ice melt - natural or man-made?
        chris Sorry, I had been discussing Hansen and RC with Phillipe and Patrick and got confused. Chalk it up to a senile moment.
129565. Quietman at 02:23 AM on 21 October 2008
        Arctic sea ice melt - natural or man-made?
        Patrick Thank you for your thoughts on this. Quite logical and I agree with your summation.
129566. Patrick 027 at 16:04 PM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        (PS thanks, chris) ... Just for insight's sake: Two other dark horse candidates: 1. solar eclipse frequency and spatical distribution changes. 2. Changes in 'moonshine' (averaged over the lunar month) or variations in 'moonshine' (changes in lunar cycle) Both these being due to variations in the orbits of the Earth around the sun and moon about the Earth. Of course, without even bothering with explicit calculations, I would rule these out off the bat as significant to climate variations on just about any timescale - with one intriguing caveat: I wonder what effect these (and the tides) might have had in the first several millions (? - unsure of how fast the moon receded) of years of Earth's history (after the moon-forming impact, of-course - and some cooling; I doubt it would be of much significance to climate over a magma ocean!).
129567. Patrick 027 at 15:47 PM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        To clarify - just to be clear, while I mentioned that some feedbacks to any warming should tend to cool the stratosphere - although others may warm it - my understanding is that the expectation of warming stratosphere from positive solar solar forcing and cooling stratosphere from positive GHG forcing both include the expected feedbacks. Of course, feedbacks won't be exactly as expected, but the individual feedback components might be observed and their effects calculated and compared to the model feedback effects, etc... (I don't know if that's really been done or not or how much). Summarizing the gist of all that - while feedbacks have uncertainties, the forcing mechanism and amount is well understood for GHGs, solar TSI (maybe a bit more uncertainty with amount), and volcanic aerosols. Anthropogenic aerosols have more uncertainty. One could make a list of dark horse candidates (PDO-ENSO cloud feedback (as in Spencer) greatly magnifying internal variability, tidal forcing - oceanic effects, geothermal variations, geomagnetism and non-TSI or non-UV solar forcing) - for some of these, a potential for a mechanism can be identified, though at least for me there is skepticism that the magnitude of the effect could be significant; for others, mechanisms can be imagined but there is a lack of information about their reality (to my knowledge). For others, there may be enough information already to rule out any significant contribution at least to the recent climate change on the AGW-relevant time-scale. Or some middle ground among those three conditions may apply. (I did my best to reason through some of this in "It's volcanoes"...) One thing these (those with potential, anyway) all have in common, to varying degrees, is greater uncertainty regarding any potential significance. This is in addition to any climate feedbacks, so without some specific reason to the contrary, there is greater uncertainty with these than with the more 'established' climate forcings. Note that it generally makes more sense to use what is known to shed light upon the unknown (ie that using what we know, we either can or can't explain observations/data, to whatever degree; therefore it is less likely or more likely, to whatever degree, that something we haven't accounted for is important after all) than it does to take the potential for importance of unknowns to find error in what was thought to be known.
129568. chris at 07:20 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Re #265 Quietman, the reassessment of tropospheric temperature measurements, especially those over the tropics, were the results of the efforts of a large number of scientists who identified artifacts especially in the radiosonde readings. This work is very widely published in the scientific literature (several of the relevant papers highlighting the radiosonde errors are listed in my post #263, just above). The resolution of apparent disparities between models and tropospheric emperatues has been widely resolved (see report of the Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research cited in my post #263)....the more specific resolution of apparent disparities in the tropical data is described in this paper: B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. None of this has any particular relationship to Real Climate (where did you get that idea?). It's widely verifed research from a large number of different sources published in the scientific literature. So nothing to do with Real Climate, but everything to do with careful science published widely in the scientific literature!
129569. Quietman at 07:07 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Patrick On the double error you are right, I repeated what I read and should have known better since it is not a linear response. I apologise for repeating the error. I don't remember where I read it now as it was about a year ago. chris Re: 263 - I was aware of this and agree. Re: models - I posted a link to an article from 2007, I think october, on model accuracy/inaccuracy in the appropriate thread here under the "arguments" heading a while back. As far as I am aware your point FIVE is the opinion expressed on Real Climate but I have not seen it on any other web site, and as you know I do not trust that site. Too much of an agenda there.
129570. chris at 06:03 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Re Quietman 259/151 You might be interested in reading my post #263, since it was you (your post #151) who initially questioned the predictive powers of modelling. In addition to Patricks examples, the examples in post #263 document pretty unequivocably that: ONE: the marked asymmetry between Arctic warming (it was predicted to warm a lot) and Antarctic warming (very little in the early stages of greenhouse waming), was predicted already in the early-mid 1980's TWO: That the extent of warming by the year 2000 was predicted rather accurately in 1975 by Wallace Broecker THREE: Hansen's models set up in the early 1980's have done a good job in predicting the temperature rise in the subsequent 20 years (notwithstanding various efforts to trash this work-see Patrick's post #262!) FOUR: Model predictions of enhanced tropospheric moistening were shown to be correct despite strenuous efforts by at least one prominent scientist to suggest that the models would be wrong. FIVE: Model predictions of enhanced tropospheric warming were eventually vindicated despite apparent discrepencies with real world measurements, the latter turning out to have been incorrect. So climate modelling has done a pretty good job so far of predicting multiple effects of massive enhancement ofr atmospheric greenhouse gas levels.
129571. chris at 05:43 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Re #258 Patrick (in reference to your response to the Monty Python style "what did the Romans ever do to us" request in #151 for predictions "that pan out for a change"): The predictions of a greatly delayed response of the Antarctic to greenhouse-induced warming and a marked asymmetry of warming between the high Northern and high Southern latitudes, were made in 1981 by Schneider and Thompson, and in more detail by Bryan et al in 1988. Describing these early modelling predictions of a greatly reduced Antarctic warming compared to predicted enhanced warming in the high Northern latitudes, Manabe and Stouffer state [in their recent review: Role of Ocean in Global Warming; J. Meterolog. Soc. Jpn. 85B 385-403.(2007)]: [“They [Bryan 1988] found that the increase in surface temperature is very small in the Circumpolar Ocean of the Southern Hemisphere in contrast to high latitudes of the Northern Hemisphere where the increase is relatively large.”] In other words the very marked asymmetry between the marked warming of the high Norther latitudes, compared to the very small expected warming in the deep S. hemisphere was predicted at least 20 years ago. I've outlined this in more detail in my post # 66 on this thread. Some other examples (of quite a large number in addition to your examples) in which climate predictions from calculations and modelling have turned out to be prescient (i.e. reality has subsequently matched the models): In addition to Hansen's rather good prediction of greenhouse gas warming from models set up and run from the early 1980's it's worth pointing out that already in 1975, Wallace Broecker was calculating (i.e. modelling) the warming expected in the future from continuing increases in greenhouse gas emissions: In his paper: Broecker, WS (1975) “Climate Change: Are we on the brink of a pronounced global warming? Science 189, 460-463 Broecker says (referring initially to the small N. hemisphere cooling observed in then-recent times): "...This cooling has, over the last three decades, more than compensated for the warming effect produced by the CO2 released into the atmosphere as a by-product of chemical fuel combustion. By analogy with similar events in the past, the present natural cooling will, however, bottom out during the next decade or so. Once this happens, the CO2 effect will tend to become a significant factor and by the first decade of the next century we may experience global temperatures warmer than any in the last 1000 years….” Broecker then goes on to describe predictive modelling of anthropogenic CO2-induced warming, taking account known levels of CO2 emissions from the UN and a projection (3% per year) of the increase in emissions, the best estimates from measurements of the emitted CO2 sequestered in the oceans and the terrestrial environment and the known warming properties of atmospheric CO2. His modelling came up with the following prediction. The Earths temperature in 2000 would be around 0.9 oC warmer than the 1900 baseline temperature. The Earth is around 0.8 oC warmer now than it was at the start of the 20th century. Not a bad prediction. Why was his prediction so good? I expect he was partly lucky since the strengths of the various contributions to climate were not so well known then as now. But, basically he was about right because the effects of atmospheric CO2 in causing warming of the Earth via the greenhouse effect were well known and easily calculated. Two other related examples of the rather strong predictive power of climate and atmospheric modelling are interesting, since in each case the predictions initially semed like they might not accord well with reality (and in the first case was strongly argued against by at least one prominent scientist) ONE: Atmospheric greenhouse theory, incorported into climate models predict/ed that as the atmosphere warms in response to raised CO2, so the atmospheric water vapour levels would rise. This prediction was strongly opposed by a very few scientists, most notably Richard Lindzen, who asserted that the troposphere would dry in response to raised CO2 levels providing a negative feedback. In fact the data eventually showed that the presictions from models were correct [see Soden et al (2005); Brogniez H and Pierrehumbert RT (2007); Santer BD et al. (2007); Buehler et al. (2008); Gettelman and Fu (2008)…and so on (citations below]. An example where a major prediction from modeling was contested, but the models were subsequently vindicated by real world measurements. TWO: Atmospheric greenhouse theory incorporated into climate models predict/ed that the troposphere should warm relative to the surface. Early tropospheric temperature measures seemed to contradict this prediction. However it turned out in time that errors in tropospheric temperature measures were responsible for the discrepancy and by 2006 the U.S. Climate Change Science Program (CCSP) who investigated this issue stated that there is ‘no significant discrepancy’ between surface and tropospheric warming, consistent with model results (Karl et al., 2006). However there has still remained a potential discrepancy between model predictions and tropospherical temperature measurements in the tropics. However recent work has again shown that the errors likely lie in the temperature measures (largely radionsides/weather balloons) [see Sherwood (2005); Thorne (2007); McCarthy (2008); Haimburger (2008)], and again it appears that the predictions from the models have turned out to be correct (Santer et al 2008). B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. ------------------------- Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912 Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110 Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289 Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253 Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844. ----------------- S. C. Sherwood et al. (2005) Radiosonde Daytime Biases and Late-20th Century Warming Science 309, 1556 – 1559. L. Haimberger et al (2008) Toward Elimination of the Warm Bias in Historic Radiosonde Temperature Records—Some New Results from a Comprehensive Intercomparison of Upper-Air Data. J. Climate 21, 4587-4606. M. P. McCarthy et al. (2008) “Assessing Bias and Uncertainty in the HadAT-Adjusted Radiosonde Climate Record”. J. Climate 21, 817-832. P. W. Thorne et al. (2007) Tropical vertical temperature trends: A real discrepancy? Geophys. Res. Lett. 34, L16702. ---------------- Karl TR, Hassol SJ, Miller CD, Murray WL (eds). 2006. Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences. A Report by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. National Oceanic and Atmospheric Administration, National Climatic Data Center: Asheville, NC; 164.
129572. Patrick 027 at 05:42 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        0.1 (PS after a while you might figure out what these numbers meand): Attribution: To clarify: "Just once? To repeat from above, stratospheric cooling"... "increased warming of nights" ... I also noted that stratospheric ozone depletion could also qualitatively explain stratospheric cooling (and some amount of tropospheric+surface (TPSF for future reference) warming ), and that albedo cooling such as from aerosols (of the right mix) could also qualitatively explain a decrease in diurnal temperature ranges. One key there is 'qualitatively' - for attribution, one would want the numbers. If one expects x degrees change from forcing A and y degrees change from forcing B, then one might start by looking at z/(x+y), where z is the observed change, and attribute z proportionately. One then may need to adjust that if there is some reason to suspect that the relative error in modeling/calculating is different for x and for y. If x can be modelled with more confidence than y (***ie if for x relative to y, the physics are better understood, model resolution and sub-grid scale issues are less of a concern (such as if y depends more on a smaller part of the atmosphere in particular?), or if forcing A is better known than forcing B), then it may make more sense to asign a greater likely share of the theory-observation mismatch to y. However, it would be erroneous, without some reason to do so, to just assume that y was correct and x is off or vice versa. (PS this would also apply when unforced variability is thrown into the mix). The other key is that there may additional aspects that are different for the climatic response to each forcing (as similar solar and GHG forcing of TPSF temperatures have different effects on the stratosphere). For example, increased albedo of course has a cooling effect and can't by itself explain an average TPSF warming (and there could be more subtle differences among different albedo forcings - volcanic vs tropospheric vs land cover). Absorbing atmospheric brown clouds would tend to increase the diurnal temperature range of the air volume they occupy (but that's not much to begin with, away from the surface)but could decrease the surface range, so that would be a candidate. Of course, the horizontal variations of these various aerosols and land-cover matters are quite different and that opens up another avenue for distinguishing their effects. ... One could imagine some combination of solar forcing and aerosol forcing could result in warming with reduced daytime warming, but again, 1. How would the numbers work out exactly?, 2. Other effects - So far as I know no significant albedo enhancement exists that would cool the stratosphere (reflection from below and perhaps scattering from within (? and/or the nonzero absorptivity of even relatively reflective stratospheric aerosols) may tend to warm the stratosphere slightly - **** THEN again, some climate feedbacks themselves might cause some stratospheric cooling - decreased albedo at the surface, and water vapor and the LW (greenhouse) effect of clouds with sufficiently high tops - although an increase in albedo from increased cloud cover, except over or replacing snow and ice (PS clouds over snow and ice could in some cases reduce albedo, I think) would tend to warm the stratosphere for reasons described above... But there may be some horizontal variation fingerprints to these various processes... Well, there is yet another way to distinguish - seasonal variations - ozone has seasonal variations and anthropogenic changes to ozone has seasonal variations. The seasonal variations of solar and GHG forcings, etc, may also be different. The overall seasonal variations (and spatial variations) in climate response in TPSF may be too similar but perhaps some stratospheric responses might contain clues. Then of course, there's the thermosphere, which doesn't have much ozone (chemical equilibria favor atomic oxygen over ozone and at sufficient height over diatomic oxygen, actually) but has the opposite sign of response to solar and GHG forcing. There is also of course the longer term temporal variations - volcanic aerosols have distinct pulses, anthropogenic GHGs have steadily risen, anthropogenic aerosols have their own trend, solar, etc... this can get tricky because of the internal variability on those timescales, of course. To sum up, if you have n unknowns and m equations, you can solve for the unknowns if m = n. If m > n, then any random combination of equations may yield conficting results - mathematically they can't all be true; but - these equations aren't random - they're rooted in physics and must agree with each other. Uncertainty allows for some disagreement (the ranges of allowable values won't be identical, but using many equations would tend to reduce the resulting uncertainty in the unknowns (and perhaps would then feedback as knowlegdge about how to improve some of those equations). Science is putting together a puzzle; sometimes the puzzle pieces have fuzzy edges and they don't fit precisely but additional pieces can help decide which arrangement is most likely, etc... On internal variability - that will always make attribution a little difficult but refer back to above. If we understood the forced responses better than internal variability then it wouldn't make sense to assume any little wobble outside the expected range of variability would render our models incorrect with respect to a forced response - and certainly variations within the expected range of variability don't render models in error. 0. Quietman 259: "Re: Hansen's prediction - Off by 50%, He predicted exactly twice the warming that actually occurred." That's a common misunderstanding (which had been spread by Pat Michaels). A. http://www.columbia.edu/~jeh1/2005/Crichton_20050927.pdf B. http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000836evaluating_jim_hanse.html From the later: "Perhaps the errors cancel out, but an accurate prediction based on inaccurate assumptions should give some pause to using those same assumptions into the future." These errors are errors in emissions scenarios for different greenhouse gases. However, what matters to climate science, assuming similar efficacies of those GHGs, is the history of the sum of those forcings. From the earlier, in footnotes: " Climate sensitivity is usually expressed as the equilibrium global warming expected to result from doubling the amount of CO2 in the air. Empirical evidence from the Earth’s history indicates that climate sensitivity is about 3°C, with an uncertainty of about 1°C. A climate model yields its own sensitivity, based on the best physics that the users can incorporate at any given time. The 1988 GISS model sensitivity was 4.2°C, while it is 2.7°C for the 2005 model. It is suspected that the sensitivity of the 2005 model may be slightly too small because of the sea ice formulation being too stable. " I would guess then that running the same model from 1988 with the realized forcing history would produce a bit too much warming, but not so much more (assuming 2005 model is more accurate, (4.2-2.7)/2.7 = 1.5/2.7 = 5/9. Okay, that is just over 50 % error, BUT that is not twice the warming, that is just over 1.5 times the warming. And the last part of that footnote suggests the error may be a bit less than that.
129573. chris at 04:15 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Re #259 I'm skeptical about your comments re Hansen's forecast of global temperature change under the influence of enhanced greenhouse-induced warming. You suggest that "he predicted exactly twice the warming that actually occurred." Can you indicate how you come to that conclusion? I'm interested in the evidence that informs your opinion..
129574. Quietman at 03:21 AM on 20 October 2008
        Volcanoes emit more CO2 than humans
        Patrick Your explanations and willingness to look at both sides is exactly why I asked you to come to this site. In most cases I can see your logic and find it convincing. Keep in mind that this type of science is new to me. I have a beckground in engineering research (product developement) and bench testing emissions but I have never done well with theoretical math only logic and applied math, so keep it simple. Trust me, it is just as frustrating for me when someone points to a paper and claims it as fact without a logical explanation as it is when I get quoted from a bible passage. The fact that you don't resort to that is quite refreshing.
129575. Quietman at 03:07 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        I will try to reply to the rest when you finish your analysis. Sounds good so far.
129576. Quietman at 03:03 AM on 20 October 2008
        Arctic sea ice melt - natural or man-made?
        Patrick Re: Fire and Ice - Sorry, I should have. Re: Hansen's prediction - Off by 50%, He predicted exactly twice the warming that actually occurred.
129577. chris at 02:08 AM on 20 October 2008
        Does model uncertainty exagerate global warming projections?
        Wondering Aloud, HealthSkeptic, Mizimi I thought you guys (gals?) are supposed to be skeptics!So what do you make of the "graph" reproduced in post #8? Let's have some considered thought and opinion. (hint: The data presented is nonsense - can you see why?)
129578. Patrick 027 at 15:05 PM on 19 October 2008
        Arctic sea ice melt - natural or man-made?
        (continued from comments 96 - 104, and perhaps 95, at "It's volcanoes (or lack thereof)") 1. 'solar dimming/brightenning' - I'm not sure what terms are used for what exactly here, but this is confusing, because it sounds like one is discussing solar TSI changes, when it was intended to discuss global dimming - the reduction in solar radiation reaching the surface. Global brightenning might not even be the opposite of that - I could imagine global brightenning might be used to refer to an incress in albedo as seen from TOA (top of atmosphere) - PS hypothetically if this occurs it could be seen on the dark portion of the moon - Earthshine reflecting off the moon's night side. I don't know if there are any observations indicating a trend in that or not. 2. Quietman 87: "Fire under the ice International expedition discovers gigantic volcanic eruption in the Arctic Ocean" http://www.eurekalert.org/pub_releases/2008-06/haog-fut062508.php You should post that website under "It's volcanoes"... - it's the first I've seen with actual evidence of a change in volcanism. However, the changes are still just on the scale of individual eruptions - Whether the the lack of knowlegde of prior such eruptions is an actual knowledge of a lack of prior such eruptions depends on whether it could have been expected to be noticed or missed - in this case I am very skeptical that there is any evidence at all of a trend here. And even if there were, I am very skeptical it could account for any significant portion of climate change, even regionally (consider the numbers - the actual geothermal heat output of an eruption compared to the actual heat going into the ocean - and by the way, remember that the global average geothermal heat flux at the surface is a little under 0.1 W/m2, and most of that is just thermal conduction through a temperature gradient in solid rock (and groundwater, but in most areas I don't think it's sufficient to drive groundwater convection?? or that groundwater flow is fast enough to cause rapid changes), with radioactive heat contributions - nothing that could change fast, except maybe where there's fast-flowing groundwater or hydrothermal vents, and how fast could those change on what timescales...?). 3. Notice in Quietman 107: "Surface warming by the solar cycle as revealed by the composite mean difference projection" "Charles D. Camp and Ka Kit Tung Received 29 March 2007; revised 15 May 2007; accepted 14 June 2007; published 18 July 2007. Geophys. Res. Lett., 34, L14703, doi:10.1029/2007GL030207." " [12] We will argue in a separate paper that the observed warming is caused mostly by the radiative heating (TSI minus the 15% absorbed by ozone in the stratosphere), when taking into account the positive climate feedbacks (a factor of 2?3) also expected for the greenhouse warming problem. " I haven't seen it myself but it sounds like they've found some reason to think that it is indeed solar TSI forcing at the tropopause (or nearly that) and not some aspect of solar forcing that wouldn't apply to GHGs - perhaps a difference in timing between TSI and solar wind variations, etc.? 0. Quietman 151: "The lies come from both deniers and alarmists, those of us who are skeptical do not need to lie, we simply ask for proof of your hypothesis. Make a prediction that pans out for a change, just once, and you will convince us skeptics. So far it's a no hitter. " Just once? To repeat from above, stratospheric cooling (with some qualifications because ozone depletion contributes, but there may be some spatial-temporal distinction there, and attributed proportions should be calculable - ie that ozone could only account for x, GHG's for y, etc..); increased warming of nights (the trend has not been constant but it's in there)... These two things would not be explained by solar forcing. The increased night warming could be explained by volcanic and anthropogenic aerosols if the forcing is sufficient - ie they do have the quality of cooling days more than nights... Add to that: Svante Arrhenius (spelling?) over 100 years ago (maybe 200?) predicted warming from CO2 increases. James Hansen 1988 - his graph for the forcing scenario most closely matched has thus far stayed close to the temperatures. And: Increased storm activity in the Arctic. Some other circulation changes - there may be evidence of expansion of the Hadley cell, for example. I think evidence of changes in rainfall patterns (space and time, etc.). And: greater warming in the Northern Hemisphere, with especially lower warming in the ocean around Antarctica and in the North Atlantic near Greenland (granted I'm not sure when these predictions were first made but at least for the first part (ocean around Antarctica), it's in a book from 1994. And: simple one-dimensional radiative-convective models from a few decades ago. And: extending the record back even farther with new data, the correlation between CO2 (and CH4) and climate continues. And: glaciers melting around the world - not just Greenland, not just Arctic sea ice, not just Kilomanjaro - and among other tropical glaciers, evidence that it is unusual in the last several thousand years (- that the ice is that old, in other words - yes, ice can flow, but there are some details - that for example, in the ice core, no evidence of melt going back x years, and then the team returns to the site and they find the ice is melting... something like that). And: sea level rising. ocean heat content increasing (that and a number of other things above argue against this all being urban heat islands - that and maybe also the lack of warming in SE U.S. - after all, there are cities there, aren't there - or have they not been growing as fast as other urban areas?). And: both the observations and the theory are a bit unclear on this one, but it does seem like tropical cyclones have been getting more intense - if not more numerous (outside the Atlantic multidecadal cycle)... to be continued...
129579. Patrick 027 at 14:17 PM on 19 October 2008
        Volcanoes emit more CO2 than humans
        Since much of what I am about to say applies to the "Arctic sea ice"... , I'm going to post a few comments there now. If after that I haven't covered some of what was brought up here in comments 87-95, I'll come back here.
129580. Patrick 027 at 14:13 PM on 19 October 2008
        Volcanoes emit more CO2 than humans
        ... of course, I've never been quite clear on 'global dimming - H2O evaporation' - of course if water is being heated to higher temperature, the tendency is for faster evaporation under the same wind and relative humidity. But there has been global warming along with 'global dimming' (? - according to some comments at "Arctic sea ice..."), so how does decreased solar radiation reaching the surface affect evaporation independently of temperature? Is it analogous to the photoelectric effect - in this case, individual higher energy photons are able to kick off H2O molecules into the air even if the temperature is low (but not too low)? Sounds conceivable, but then again, the absorption of solar radiation is distributed within a depth of water from the surface downward; less so for the shortest wavelengths, red light and solar IR, but I suspect it's a tiny tiny fraction that would be absorbed within a 'molecular layer' or two from the surface.
129581. Patrick 027 at 14:04 PM on 19 October 2008
        Volcanoes emit more CO2 than humans
        "so perhaps this is partly why I hear of atmospheric brown clouds (dark absorbing aerosols) in particular reducing vertical motion by increasing stability." Actually, the full effect may be an increase in stability to moist convection by reduction in evaporation; in so far as dry convection is concerned, while the heating has been moved upward from the surface, it won't generally be all the way up to the tropopause; while there will tend to be increased stability beneath such a brown cloud, there will tend to be reduced stability above it. The heating of the brown cloud itself will tend to cause a low pressure beneath it and a high pressure above it, and the brown cloud itself will tend to rise.
129582. Patrick 027 at 13:13 PM on 19 October 2008
        Volcanoes emit more CO2 than humans
        ... or 5. internal variability greater than thought __________ About efficacy of forcings: I haven't actually read much about that but here's what I would expect: Consider a forcing by Solar TSI LW (greenhouse) forcing volcanic stratospheric aerosols tropospheric aerosols surface albedo For any given forcing - let's start with radiative forcing - there is: 1. a global average TOA (top of atmosphere) value, R-TOA. 2. a global average tropopause value, R-tp 3. a global average surface value, R-sfc. 4. Some spatial-temporal (seasonal, perhaps interannual) variation in either of R-TOA, R-tp, R-sfc, which I will simply refer to here as R-var. 5. Some climatic response which results from the effect of R and feedbacks. - To start with, we might assume an approximation that the climatic response in so far as global average is concerned, is similar to any R-tp or R-TOA for any forcing. Then we might look for deviations from that. Differences: R-TOA is the forced net change in downward minus outgoing radiation 'at' the top of the atmosphere. R-tp is different then R-TOA; both are different from R-sfc - First: 1. An increase in solar TSI - if the same % increase at all wavelengths - the forcing is a heating distributed (unevenly) through the atmosphere and surface. R-TOA is the sum of all of this heating; R-tp is only the heating below the tropopause and is therefore somewhat less than R-TOA; R-sfc is only surface heating and is therefore less than R-tp. Typically changes in solar TSI are greater in UV in particular, so a larger fraction than otherwise of solar forcing goes into heating the upper atmosphere, thus decreasing R-tp even further. 2. Greenhouse forcing is a reduced cooling to space, which is a heating of the surface and/or lower atmosphere. The cooling to space of the stratosphere and above, however, increases, while the heating of higher atmospheric layers by the surface and/or lower troposphere decreases. Thus for greenhouse forcing, R-TOA will be a little less then R-tp. Starting at minimal LW opacity, R-sfc might be greater than R-tp (?), but at least for CO2, my impression is increases from the current amount result in greater R-tp than R-sfc. Water vapor is a feedback, but applying the same concepts to water vapor, I think, at least under some conditions, R-sfc is greater than R-tp for water vapor. This is at least in part due to water vapor's increasing concentration toward the surface. Ozone concentration is also variable so greenhouse effects of ozone changes may be a bit different than the 'typical' well-mixed greenhouse gas. The exact relationship between R-tp, R-sfc, and R-TOA for even well-mixed greenhouse gases (like CO2, CH4, N2O, CFCs) (they have some spatial and seasonal variations but not to the degree of ozone or water vapor) could vary because they have different spectrums, and temperature (and water vapor, ozone, cloud content) varies with height (and other dimensions), they may overlap with each other and other things in different ways due to the above differences, and they have different initial amounts before changes occur. 3. a decrease (to keep the same sign of forcings for more straightforward comparison) in volcanic stratospheric aerosols - this would reduce albedo. The aerosols reflect SW (solar) radiation back up from the stratosphere, thus cooling the troposphere and surface but possibly heating the air above; and perhaps heating the stratosphere a little bit (? I think the stratosphere or some part of it actually warms up after relevant eruptions - this might be due to the nonzero absorption of solar radiation by the aerosols themselves) (some of the solar radiation is scattered downward or sideways - for a near-overhead sun (middle of day, summer midlatitude, or at low latitude), this can increase the path length before reaching the surface, thus increasing the portion absorbed in the air...) ... SO scattering of radiation is complicated (but not so much that it isn't understood), but reducing volcanic aerosols results in an R-sfc and R-tp greater than R-TOA, and I suspect R-sfc would be greater than R-tp. 4. tropospheric aerosols 4a. A decrease in the albedo from reduced scattering by aerosols: R-sfc will be greater than R-tp and R-TOA as some of the reflected and scattered radiation had been absorbed by air and clouds. 4b. An increase in the atmospheric heating by increased absorption of aerosols: R-TOA and R-tp will be positive while R-sfc is negative. 4c. scattered radiation can be subsequently absorbed in the air; the total effect of aerosols is not simple, but again, it isn't an impossible riddle either. 5. Decrease in albedo due to surface conditions: The change in albedo actually at the surface may have to be greater than that which results at TOA, due to clouds, but also time of day and year issues, and latitude. Anyway, reflected solar radiation has a second chance to be absorbed by the air, so the decrease in albedo because of surface conditions may result in R-sfc greater than R-tp and R-tp greater than R-TOA (but perhaps only slightly). HOWEVER: R-tp may be (as it is in IPCC work) defined as that which occurs after the stratosphere and above have reached thermal equilibrium with the forced heating or cooling (R-TOA - R-tp) which occurs there (PS notice this is not the same as that equilibrium which would result after the climate response including the tropsophere and surface). If R-TOA is greater than R-tp, then the stratosphere, etc, will have warmed, so R-tp will be a little higher as a result due to increased downward LW radiation (or a decrease in net upward LW radiation). If R-TOA is less than R-tp, the opposite will be true. In other words, R-tp will get closer to the original R-TOA (But I don't think it would be equal to the original R-TOA - I expect it to still be less or greater than R-TOA, whichever was the case to begin with). R-sfc might also shift in the same direction but not as much so long as there are any greenhouse agents within the troposphere. Of course, in the full climatic response, however tropospheric heating (R-tp - R-sfc) is distributed within the troposphere, or however much it is, as an upper layer warms up, it reduces convective heat transport from below, thus the tendency is for the full effect of R-tp to propogate by convection to the surface, whatever R-sfc was. However, a larger R-tp - R-sfc and/or smaller or negative R-sfc value will tend to reduce convection from the surface - HOWEVER, after all feedbacks have occured, the radiative heating/cooling distribution may be different again. ***I think this would be less true for regionally-concentrated forcings (pockets of high aerosol concentrations, for example), because advection into and out of the area would prevent a radiative convective equilibrium on the regional scale, so perhaps this is partly why I hear of atmospheric brown clouds (dark absorbing aerosols) in particular reducing vertical motion by increasing stability. So a global average R-tp will tend to result in some global average tropospheric and surface temperature increase. Some other effects due to the vertical distribution may change the feedbacks that occur and thus the resulting temperature changes in the surface and troposphere - but to my knowledge that is not a big effect (?). The horizontal (and seasonal, if and when it matters (ozone)) variations could also affect the actual global average results. For example - the R-tp and R-TOA of albedo reduction from BC landing on snow/ice will likely be a little smaller than the R-sfc value (some radiation reflected from the surface can be reflected back to the surface by clouds, aerosols, and air molecules); furthermore and perhaps much more importantly, the effect is concentrated where a positive feedback is also concentrated (snow-ice albedo feedback). Thus the climate sensitivity could be expected to be larger to BC on snow/ice forcing than to some other forcings, to the extent that the forced heating is not entirely advected away from similar locations. As far as anthropogenic well mixed greenhouse gases (WMGHG - to adopt the acronymn I saw in a paper - this includes CO2, CH4, N2O, CFCs - well, at least a couple CFCs) compare to solar radiative forcing - the geographic distribution of R-tp is going to be at least a little similar on a broad scale - the LW forcing is highest in the subtropics because of the relatively dry cloud-free air and higher lapse rates; high cloud tops in the tropics prevent greenhouse gases below them from having any direct effect on R-tp; lower tropospheric and surface temperatures in general and smaller lapse rates at higher latitudes reduce the difference in outgoing LW radiation (at least at tropopause level - and the tropopause is lower there, too) that would result from changing greenhouse gas concentrations (and the lower surface temperatures. Solar forcing will generally be greatest at low latitudes, during the day, and/or in summer, where there are fewer clouds, reflective aerosols, darker surfaces (ocean, forests), etc. For example, the dry subtropics (but unlike WMGHGs, solar forcing would not be as large over dry light-colored landscapes as it would be over dark oceans). Etc. R-tp will be higher than otherwise when there is less stratospheric ozone. There is a latitudinal and seasonal ozone variation - there tends to be more ozone at higher latitudes in winter/spring, I think - because while stratospheric ozone is produced more at low latitudes, winter stratospheric circulation brings it into high latitudes, and actually 'piles it up' there, in part (if not in whole) because the stratosphere is thicker at higher latitudes (lower tropopause)... ---- Of course anthropogentic GHG forcing is expected to result in a cooler stratosphere (observed - although stratospheric ozone depletion also has a similar effect - but each can be calculated so it should be possible to attribute portions of cooling), and greater warming at nights during days near and at the surface over land (not much diurnal cycle to begin with over oceans because of heat capacity) - (also observed, at least somewhat). Positive solar forcing that would warm the surface and troposphere would also warm the stratosphere (not observed). However, because of this, there could be effects on atmospheric circulation that are different than for GHGs, which might affect climate sensitivity (but how much and in what direction?).*** (Quietman - if you want to show a reduced climate sensitivity by way of greater total forcing, you might try looking into how solar forcing, including non-TSI or non-UV effects, affect not only the stratosphere, but also the ionosphere, and for example the E-region dynamo, and how geomagnetic effects also affec the E-region dynamo and solar-magnetospheric-ionospheric interactions, and what any resulting circulation pattern changes would be, and if and how that propogates downward. I am not saying that I expect you to be successful, but it's a thought - while I have my doubts, I think it's got a lot more potential than submarine volcanism, solar jerk, tides on sun, Spencer's PDO+ENSO work, Spencer's cloud forcing work, urban heat island dominance, or the idea that there hasn't been a recent spurt of global warming above and beyond internal variability.)
129583. chris at 07:14 AM on 19 October 2008
        Models are unreliable
        Re #56 Quietman, the posting of your link to a paper purporting to identify an incompatibility between tropospheric temperatures in the tropics and modelled tropospheric temperature is fascinating. Here’s a very recent paper by a large group of 17 climate scientists. It (abstract at bottom of post) completely contradicts the paper that you linked towards: B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. You can download and read it from here: https://publicaffairs.llnl.gov/news/news_releases/2008/NR-08-10-05-article.pdf What can be going on? The answer is the guys whose paper you linked towards (Drs Douglass, Christy, Pearson and Singer; DCPS) messed up somewhat (incidentally you should always be a little suspicious of papers containing the rather dubious S. Fred Singer). Here’s the story: 1. Simple atmospheric physics indicates that as the atmosphere warms under the influence of raised [CO2], a water feedback (raised water vapour in a warming atmosphere) should kick in resulting in additionally raised atmospheric temperature. This is observed in models (both the raised water vapour and atmospheric temperature), and is generally consistent with real world measurements. 2. But not fully. There has been an apparent mismatch between predicted tropospherical warming and measured warming in the tropics. Radiosonde data (crude temperature measures in weather balloons) especially, don’t seem to show the predicted temperature increase. Something is wrong. 3. But what? In this case it looks like it might be the measurements that are wrong. In fact the paper you linked towards (DCPS) was not so much about demonstrating that there is a mismatch between the models and tropical tropospheric temperature measures (there quite likely isn’t), but in asserting that the tropospherical tropical temperature measurements are sufficiently free from error that such a comparison can be reliably made. In fact it seems that they aren’t. 4. What does the evidence indicate? It’s been known for some time that there is a very significant problem with the radiosonde tropospheric data, and this is particularly severe in the tropics. If these errors are taken into account, then the model and tropical tropospheric temperature can be be reconciled. However this requires a recognition of the substantial errors in the measured raiosonde data and a proper evaluation of these errors when assessing any real or potential disparity with the models. S. C. Sherwood et al. (2005) Radiosonde Daytime Biases and Late-20th Century Warming Science 309, 1556 – 1559. Abstract: “The temperature difference between adjacent 0000 and 1200 UTC weather balloon (radiosonde) reports shows a pervasive tendency toward cooler daytime compared to nighttime observations since the 1970s, especially at tropical stations. Several characteristics of this trend indicate that it is an artifact of systematic reductions over time in the uncorrected error due to daytime solar heating of the instrument and should be absent from accurate climate records. Although other problems may exist, this effect alone is of sufficient magnitude to reconcile radiosonde tropospheric temperature trends and surface trends during the late 20th century.” L. Haimberger et al (2008) Toward Elimination of the Warm Bias in Historic Radiosonde Temperature Records—Some New Results from a Comprehensive Intercomparison of Upper-Air Data. J. Climate 21, 4587-4606. M. P. McCarthy et al. (2008) “Assessing Bias and Uncertainty in the HadAT-Adjusted Radiosonde Climate Record”. J. Climate 21, 817-832. P. W. Thorne et al. (2007) Tropical vertical temperature trends: A real discrepancy? Geophys. Res. Lett. 34, L16702. And so on… 5. And in fact, if tropical tropospheric temperatures are assessed using other measured correlates of temperature, there is increasing evidence that in fact the tropical troposphere is warming as predicted: Allen RJ and Sherwood SC (2008) Warming maximum in the tropical upper troposphere deduced from thermal winds. Nature Geoscience 1, 399-403. Abstract: "Climate models and theoretical expectations have predicted that the upper troposphere should be warming faster than the surface. Surprisingly, direct temperature observations from radiosonde and satellite data have often not shown this expected trend. However, non-climatic biases have been found in such measurements. Here we apply the thermal-wind equation to wind measurements from radiosonde data, which seem to be more stable than the temperature data. We derive estimates of temperature trends for the upper troposphere to the lower stratosphere since 1970. Over the period of observations, we find a maximum warming trend of 0.65 +/- 0.47 K per decade near the 200 hPa pressure level, below the tropical tropopause. Warming patterns are consistent with model predictions except for small discrepancies close to the tropopause. Our findings are inconsistent with the trends derived from radiosonde temperature datasets and from NCEP reanalyses of temperature and wind fields. The agreement with models increases confidence in current model-based predictions of future climate change." 6. What are the conclusions? The first is that one should be carefully not to be fooled by dubious papers that are circulated around the blogosphere to fool the unwary. There are usually a number of papers that are relevant to assess particular issues, and one should try to address all of the evidence. Secondly, one can only assess the relationship between predicted/modeled analyses and real world data if the real world data is sufficiently accurately defined to make a valid comparison. Although this is often the case, in the particular instance of measured tropical tropospheric temperatures, the evidence indicates that the real world measurement errors are still too large. However as Santer et al indicate, they are improving, and there is now no substantial disagreement between modelled and measured data. ----------------------------------------------------- B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722. Abstract "A recent report of the U.S. Climate Change Science Program (CCSP) identified a potentially serious inconsistency between modelled and observed trends in tropical lapse rates (Karl et al., 2006). Early versions of satellite and radiosonde datasets suggested that the tropical surface had warmed more than the troposphere, while climate models consistently showed tropospheric amplification of surface warming in response to human-caused increases in well-mixed greenhouse gases (GHGs). We revisit such comparisons here using new observational estimates of surface and tropospheric temperature changes. We find that there is no longer a serious discrepancy between modelled and observed trends in tropical lapse rates. This emerging reconciliation of models and observations has two primary explanations. First, because of changes in the treatment of buoy and satellite information, new surface temperature datasets yield slightly reduced tropical warming relative to earlier versions. Second, recently developed satellite and radiosonde datasets show larger warming of the tropical lower troposphere. In the case of a new satellite dataset from Remote Sensing Systems (RSS), enhanced warming is due to an improved procedure of adjusting for inter-satellite biases. When the RSS-derived tropospheric temperature trend is compared with four different observed estimates of surface temperature change, the surface warming is invariably amplified in the tropical troposphere, consistent with model results. Even if we use data from a second satellite dataset with smaller tropospheric warming than in RSS, observed tropical lapse rate trends are not significantly different from those in all other model simulations. Our results contradict a recent claim that all simulated temperature trends in the tropical troposphere and in tropical lapse rates are inconsistent with observations. This claim was based on use of older radiosonde and satellite datasets, and on two methodological errors: the neglect of observational trend uncertainties introduced by interannual climate variability, and application of an inappropriate statistical consistency test."
129584. chris at 05:28 AM on 19 October 2008
        Models are unreliable
        Re #57, on CO2 and feedbacks. There is a large amount of paleodata on the relationship between Earth’s paleotemperature data and paleoCO2 measures, and these indicate that the Earth in the deep past was warm when atmospheric CO2 levels were high, and cool/cold when atmospheric CO2 levels were low. Some of these data are listed at the bottom of the post (data set #2).. Dan makes an odd statement about the record of “30 year long up and down temperature trends during the steady progressive rise in atmospheric carbon dioxide level of the 20th century”. But one only needs to look at the temperature record (e.g. http://data.giss.nasa.gov/gistemp/), to see that the trend is a positive one. The earth’s surface temperature is undergoing a rapid increase in temperature that is following the extraordinarily rapid rise in atmospheric CO2. But one needs to be careful of course. The temperature rise that results from enhanced atmospheric CO2 levels relates to the temperature AT EQUILIBRIUM. There are two problems with Dan’s simple misrepresentation. Internal variations in the climate system (ocean currents, El Nino’s, La Nino’s) that temporarily redistribute heat, the effects of volcanic eruptions that transiently cool the atmosphere (or man made aerosols), the solar cycle, and so on, result in fluctuations around the equilibrium temperature that is effectively “set” by the solar output and the greenhouse effect. So we obviously don’t expect to see a perfectly steady increase in temperature as CO2 levels rise. The earth’s temperature has been rising by around 0.2 oC per decade during the last 30-odd years. However internal variation can be as large as 0.1-0.2 oC per year. So the temperature rise is overlaid with “noise” from these fluctuations. That’s pretty obvious. Likewise right now we’re smack at the bottom of the solar cycle. So for the last couple of years and for perhaps another couple the Earth’s temperature rise is being opposed by a slightly cooler sun. In a couple of years the rise in solar output will add to the greenhouse warming.. ..and so on. The fact is that when we assess the trends over longish periods, the Earth is on a warming trend…we’re around 0.5 oC warmer globally than 30 years ago. The temperature may have gone “up and down” a bit during this period...but overall it’s gone up! A large number of analyses indicate that the Earth’s EQUILIBRIUM temperature rises by around 3 oC (+/- a bit) per doubling of atmospheric CO2. A significant part of this temperature rise results from feedbacks, the most important one being the water vapour feedback. As the atmosphere warms under the influence of raised CO2 levels, so the atmospheric concentration of water vapour rises. Does this feedback actually exist? Yes. We can measure the enhanced atmospheric water vapour directly in the real world [see Soden et al (2005); Brogniez H and Pierrehumbert RT (2007); Santer BD et al. (2007); Buehler et al. (2008); Gettelman and Fu (2008)…and so on (citations below]. So the major feedback to enhanced CO2 level exists. As atmospheric CO2 levels rise so atmospheric water vapour levels rise, pretty much in expectations with predictions based on straightforward atmospheric physics (not to mention models which also predict the observed tropospheric moistening). It’s difficult to know exactly where Dan is confused with respect to “feedbacks” since he is very vague. Notice that Dan is being a tad dishonest in his comments in post #57, since I don’t refer to feedbacks as “vague” and “nebulous” at all, but to Dan’s “discussion” of these as vague (this dishonesty is similar to Dan’s pretence that my criticism of Dan’s appalling cherrypicking of paleotemperature data equates to a disagreement on my part with the data). The problem is that Dan makes very vague comments about feedbacks. He talks about “feedbacks, known or not”. He alludes to negative feedbacks without really addressing what these might be, other than alluding to a negative feedback “identified” by Dr. Richard Lindzen and “his iris effect”. But of course Lindzen didn’t “identify” an “iris effect”. Lindzen hypothesised such a possibility…however real world analysis hasn’t really provided any evidence for such a thing (see below). Lindzen earlier postulated that increased CO2-induced warming would cause a drying of the troposphere, but in the face of real world data world [see Soden et al (2005); Brogniez H and Pierrehumbert RT (2007); Santer BD et al. (2007); Buehler et al. (2008); Gettelman and Fu (2008)…and so on (citations below], Lindzen had to dump that notion too. Unverified or disproven hypothesis don't constitute evidence of anything. The problem with vague assertions about hypothetical negative feedbacks is not just that these are ill-defined, and that the evidence indicates that these hypothetical feedbacks don’t exist or are small. Real world observations support the conclusions that (i) that the climate sensitivity to raised CO2 is rather significant (around 3 oC per doubling of atmospheric CO2), and (ii) that putative, hypothetical negative feedbacks are not very significant. Thus many of the determinations of climate sensitivity are empirical analyses that relate warming to variations in forcings and accommodate all feedbacks whether negative or positive. Thus determination of a climate sensitivity to CO2 by analysis of glacial-interglacial transitions, by analysis of paleotemp/paleoCO2 data [Royer et al (2007)]; by analysis of the Earth’s temperature response to the solar cycle [Tung and Camp (2008)], and so on, implicitly incorporate all of the forcings whether negative or positive. These give values near 3 oC of warming per doubling of atmospheric CO2. Likewise we’ve had a very marked warming during the last 30 years (around 0.5-0.6 oC) in response to an increase in atmospheric CO2 from 330 ppm to 385 ppm. If we’ve had 0.5-0.6 oC of temperature rise from a “small” (!) CO2 rise of 55 ppm on the course of a potential doubling of 330-660 ppm, then that seems highly inconsistent with a low climate sensitivity; the same conclusion arises from the extent of warming we’ve had in response to a relatively small proportion of doubling of atmospheric CO2 during the 20th century. In fact the temperature increase of the 20th century, modelled using the full set of known contributions, is entirely compatible with the effects of feedbacks (Hansen et al, 2005) and predictive simulations set up in the 1980’s have done a rather good job of predicting the subsequent global temperature increase (Hansen et al, 2006) and so on. Thus it’s perverse to suggest that what exists (since we can measure it in the real world) doesn’t exist…or to assert that what doesn’t seem to exist (since there seems precious little evidence for it!), does. Dan also needs to be far less vague about his comments concerning temporal relationships between temperature and greenhouse gas levels during glacial cycles. He’s confused over something and thinks that everyone else might be wrong…but unless he is explict about his problem we’re unlikely to be able to help him… Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110 Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912 Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289 Hansen, J. et al (2005) Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435. http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf Hansen, J. et al. (2006) Global temperature change. Proc. Natl. Acad. Sci., 103, 14288-14293. http://pubs.giss.nasa.gov/docs/2006/2006_Hansen_etal_1.pdf Royer DL et al. (2007) Climate sensitivity constrained by CO2 concentrations over the past 420 million years Nature 446, 530-532 Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253 Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844. Tung and Camp (2008) Solar Cycle warming at the Earth’s surface and an observational determination of climate sensitivity http://www.amath.washington.edu/research/articles/Tung/journals/solar-jgr.pdf ------------------------------------------------- Data set #2: A wealth of paleoproxy data support the conclusion of a strong relationship between atmospheric CO2 and earth’s surface temperature during the deep past. These data support a high climate sensitivity to CO2 and indeed analysis of the relationships between paleotemperature and paleoCO2 indicate that the earth’s temperature sensitivity to enhanced CO2 has been high for 500 million years. Explicitly a value for the climate sensitivity of 2.8 oC per doubling of atmospheric CO2 has been determined (see Royer et al (2007) in the citayions listed above. D.L. Royer (2006) "CO2-forced climate thresholds during the Phanerozoic" Geochim. Cosmochim. Acta 70, 5665-5675. (this is a review compiles much of the published data) Even more recent studies supplement the information in Royers compilation and cover additional periods with new data sets right through the past several hundreds of millions of years: R.E. Carne, J.M. Eiler, J. Veizer et al (2007) "Coupling of surface temperatures and atmospheric CO2 concentrations during the Palaeozoic era" Nature 449, 198-202 W. M. Kurschner et al (2008) “The impact of Miocene atmospheric carbon dioxide fluctuations on climate and the evolution of the terrestrial ecosystem” Proc. Natl. Acad. Sci. USA 105, 499-453. D. L. Royer (2008) “Linkages between CO2, climate, and evolution in deep time” Proc. Natl Acad. Sci. USA 105, 407-408 Zachos JC (2008) “An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics” Nature 451, 279-283. Doney SC et al (2007) “Carbon and climate system coupling on timescales from the Precambrian to the Anthropocene” Ann. Rev. Environ. Resources 32, 31-66. Horton DE et al (2007) “Orbital and CO2 forcing of late Paleozoic continental ice sheets” Geophys. Res. Lett. L19708 (Oct. 11 2007). B. J. Fletcher et al. (2008) “Atmospheric carbon dioxide linked with Mesozoic and early Cenozoic climate change” Nature Geoscience 1, 43-48.
129585. chris at 05:06 AM on 19 October 2008
        Models are unreliable
        Re #57 There are some extraordinary misconceptions and lovely examples of deliberate misinterpretation in Dan’s post. Let’s have a look (a response to Dan’s “feedback” stuff in a separate post): We can examine the wealth of paleoproxy data published in the scientific literature (these can be found in the NOAA site urled in the list below, and some of these are compiled in a graph on the Wikipedia page...…more recent data sets that aren’t in the Wikipedia composite are cited below too). All of this data from a very large number of analyses indicate that we are a good bit warmer now (by 0.4-0.6 oC or more) in the Northern hemisphere now than during the so-called “Medieval Warm Period” (MWP). Dan has chosen to ignore all of the published data, and to refer us to an article in a non-science magazine who’s editor is quite open about her inclusion of (non-peer reviewed) stuff that supports her rather odd political considerations. Dan's article is scuppered by a ludicrous howler in which the author (Loehle) misunderstood the dating of paleodata and thought that his data sets progressed to the present, when in fact they extend at the very most to 1949. In other words Loehle misses out completely the very marked global scale warming of the last nearly 60 years. Loehle corrected his analysis.....now taking Loehle’s own CORRECTED data at face value his analysis demonstrates that it is a good bit warmer now that during the MWP. So Dan got it wrong. Note that although Loehle was honest enough to print a correction of his paper, Dan chose to base his original “analysis” (post #53) on the incorrect presentation even ‘though the correction is joined into the same document as the original incorrect article...that’s a dull piece of contrived misrepresentation and cherrypicking……sadly, that seems to Dan’s modus operandi (see posts #46, 48, 50, 52, 54). It’s worth noting Dan’s attempt to “rescue” the “situation”. Dan points out that Loehle still considers that the MWP might have been (in the Northern hemisphere) as warm as now. However Loehle makes another fundamental error here. Note that Loehle’s paleodata set is extremely sparse (18 records) and some of these records themselves are extremely sparse (e.g. a paleotemperature point every 100 years). This might be contrasted with the recent paleoanalysis of Mann et al (2008), for example, which also addressed the paleodata without using tree ring proxies, and who's analysis uses around 170 paleotemperature data sets with the stipulation that the data has at least decadal temporal resolution. Examination of Loehle’s original sparse records shows considerable variability, and (as is quite normal) in order to make the paleotemperature variations accessible and to incoproprate disparate sets into a common record, the data are smoothed by averaging in the time domain. Loehle used a 30 year running mean (changed to a 29 year running mean in his correction). The problem is that Loehle then chose to compare his most recent paleoproxy temperature point (the year 1935), with the instrumental temperature record (from NASA GISS: http://data.giss.nasa.gov/gistemp/) smoothed as a 29 year running average. Of course that doesn’t make any sense. We know what the earth’s land/sea surface temperature has done since 1935. It’s risen by around 0.6 oC. If one arbitrarily averages the real measured temperature with a 29 year running average, one arithmetically “magic’s” away a good bit of the warming. O.K. so Loehle’s analysis is pants on a number of levels. But for all its ludicrous faults, taken at face value it still indicates that we are a good bit warmer now (in the N. hemisphere) than during the MWP. I would suggest that if anyone is interested in looking at what the science indicates on this subject, they look at the paleodata on the NOAA NCDC database or download the very recent extensive analysis of Mann et al (2008) published as an Open Access article in the Proceeds of the National Academy of Sciences (http://www.pnas.org/content/105/36/13252.full) M. E. Mann et al (2008) “Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia” Proceedings of the Natl. Acad. Sci. USA 105:13252-13257 ------------------------------------------------------- The extensive published paleoproxy temperature data is compiled here: http://www.ncdc.noaa.gov/paleo/recons.html Wikipedia has a reasonably good account of this data, and an overlay of many of the paleotemperature proxy data can be found here: http://en.wikipedia.org/wiki/Image:1000_Year_Temperature_Comparison.png recent papers with datasets/analyses that may not be in the Wikipedia compilation are: M. E. Mann et al (2008) “Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia” Proceedings of the Natl. Acad. Sci. USA 105:13252-13257. (http://www.pnas.org/content/105/36/13252.full) D'Arrigo RD, Wilson R, Jacoby G (2006) “On the long-term context for 20th century warming.” J Geophys Res 111:D03103. Hegerl GC et al (2007) “Detection of human influence on a new, validated 1500 year temperature reconstruction.” J Clim 20:650–666. Lee TCK, Zwiers FW, Tsao M (2008) “Evaluation of proxy-based millennial reconstruction methods.” Clim Dyn 31:263–281. Viau, AE et al (2006) “Millennial-scale temperature variations in North America during the Holocene” J. Geophys. Res. 111, D09102.
129586. Patrick 027 at 04:48 AM on 19 October 2008
        Volcanoes emit more CO2 than humans
        Echoing Philippe 190: Your complaints about abuse of peer review - this really doesn't prove anything regarding AGW but it may be worthwhile to note that one line of attack by creationists/ID proponents is to complaign about how their side is 'shut out' by the scientific establishment. ---- I can see why you would have gotten upset by the tone of your opponents; however, I can see why your opponents overall could have gotten very frustrated with you and why they would have labelled you a contrarian/denier. Also, your references to bibles and fundamentalists and evolution, and suggesting that a person should think for him/herself, were offensive because they imply things about your opponents which I don't think were generally true (certainly not anymore than they would apply to yourself - no offense.). More on that later... -- I can see why you (Quietman) and chris were having a hard time discussing the conclusions/interpretations of the paper(s) which used observed responses to solar forcing to figure out a climate sensitivity, which would then apply to CO2 forcing. What would have been helpful would have been for you to explicitly state one or more of the following (whichever applies to your thoughts): 1. the efficacy of the forcings could be different (** more on that later) 2. the solar forcing may extend beyond TSI (**although I would point out the authors apparently went on to find evidence for TSI being most/all of the solar (or solar-cycle-correlated??) forcing - I am only infering this from a quoted portion in the comments). 3. solar forcing may be correlated with some other forcing. 4. CO2 forcing is significantly overestimated (which is highly unlikely, I think - refer back to our earlier discussions). Any of these might have yielded some interesting conversation?
129587. Patrick 027 at 04:29 AM on 19 October 2008
        Volcanoes emit more CO2 than humans
        Re Quietman 186 (Arctic sea ice melt...): Many different people at different times may use any given word. People change. It's not even the same people around today as back then. In today's world, the worst treatment of returning soldiers and their families of which I am aware is by a far-right-wing reverend from - Kansas? - who goes around protesting at funerals, and by the government itself, but of course none of this is pertinent to the subject at hand. I was once told in high school by an aquaintance not to say 'pasta' because it's a 'yuppie word'. I was a bit puzzled by her concern on the matter - sure it's from a foreign language and may sound 'fancy' (if you're not used to it), but ... (doesn't my using it make it not so much of a yuppie word anymore?)
129588. Patrick 027 at 04:21 AM on 19 October 2008
        Volcanoes emit more CO2 than humans
        - now up to 170... will comment more later but a brief note... Do the math. Do the math. Do the math. Do the math. Do the math. Do the math.
129589. Patrick 027 at 15:46 PM on 18 October 2008
        Volcanoes emit more CO2 than humans
        - now up to 158. Interesting. Not necessarily in a good way... :)? (PS there has not been an overall warming trend in the last five million years - if anything an overall cooling trend (PS NOT claiming it is a constant linear trend) - superimposed on which are glacial-interglacial fluctuations.)
129590. Dan Pangburn at 15:03 PM on 18 October 2008
        Models are unreliable
        A list of all legitimate indicators that human produced carbon dioxide is a substantial contributor to global warming is welcome. The record of approximately 30-year long up and down temperature trends during the steady progressive rise in atmospheric carbon dioxide level of the 20th century certainly is not one since it corroborates that there is no significant correlation between rising atmospheric carbon dioxide and global average temperature. All of my sources are cited so that they can be checked. None are misrepresented. Quoting a maximum or minimum in a data set hardly qualifies as ‘cherry picked’. The Middlebury link (post 41) includes links to all of the source data that is graphed there. The corrections to Dr. Loehle’s paper are included with the original in the link at http://www.ncasi.org/publications/Detail.aspx?id=3025 . Select ‘Download File’ to get both the original and the corrections. Contrary to assertions by Chris, review of this paper reveals that the ‘corrections’ made little change to the results. Loehle used a 29 year smoothing which allowed comparison only through 1992 at the time of the paper. The smoothed average global temperature in 1992 reached about the same as was reached during the Medieval Warm Period. Loehle describes all of the data sources and methods that were used and solicits feedback by also giving his email address. Regarding the Medieval Warm Period, this is what Dr. Loehle actually said (in the correction): “The peak value of the MWP is 0.526 Deg C above the mean over the period (again as a 29 year mean, not annual, value). This is 0.412 Deg C above the last reported value at 1935 (which includes data through 1949) of 0.114 Deg C. The standard error of the difference is 0.224 Deg C, so that the difference is significantly non-zero at the 10% level (t = 1.84). While instrumental data are not strictly comparable, the rise in 29 year-smoothed global data from NASA GISS (http://data.giss.nasa.gov/gistemp) from 1935 to 1992 (with data from 1978 to 2006) is 0.34 Deg C. Even adding this rise to the 1935 reconstructed value, the MWP peak remains 0.07 Deg C above the end of the 20th Century values, though the difference is not significant.” Utilizing information from several publications as well as the web helps to compensate for the bias, agenda, group-think and de facto censoring that can exist with a particular publication. There are undoubtedly many publications that supposedly show that added atmospheric carbon dioxide is a significant cause of Global Warming. That can happen when you start out with a conclusion and then set out to justify it. I started out with the relation of carbon dioxide and Global Warming as a question. Although I try to listen very carefully to what others say, I withhold judgment as to validity until vastly corroborated and even then remain alert to contradiction. The above and, except for mentioning feedback, the lengthy comments by Chris are not particularly relevant to the issue of reliability of GCMs. Although reliability as used here is ambiguous, I assume, as probably most do, that it means that it pertains to whether GCMs can reliably predict future climate. Maybe some day some of them will be able to but not yet. Three major issues are apparent: 1) Vertical convection is subjectively parameterized. 2) Clouds are also subjectively parameterized, and rather poorly (see post 17). 3) The users arbitrarily impose substantial positive feedback which, climate history proves is a mistake. There are other issues as listed at post 32 (Average temperature anomaly from NOAA for Jan thru Sept 2008 is 0.445). There is one exact computer of earth’s climate as I described at post 45 above. Of course any credible temperature proxy can be used as an archive of results. It appears that Chris either did not read or did not understand my earlier post (43) on feedback. Referring to feedback as “vague” and “nebulous” further verifies a lack of understanding of feedback. Failure to see the difference between the paraphrase of my words “clearly feedbacks don't exist” and my actual assertion that NET positive feedback does not exist also indicates a lack of understanding of feedback. Failing to understand feedback explains why temperature TREND reversals during the previous glaciation are not recognized as proving that significant NET positive feedback does not exist in climate. Actual temperature response is influenced by NET feedback. NET feedback is the combined effect of positive feedbacks such as water vapor, negative feedbacks such as Lindzen’s iris effect, and all other feedbacks whether recognized or not. Although the numerical values and formulation are different between engineering feedback and Ocean and Atmospheric Physics feedback, positive feedback means the same thing in both. The response is greater with positive feedback than it would be if there were no feedback. NET means the combined effects of all active feedbacks whether known or not. A temperature TREND direction change proves that there is no significant NET positive feedback. Any credible source of temperature can be used. All that is needed to determine that there is no net positive feedback is a temperature trace for a long enough time to average out cyclic variation from random noise and other factors such as ENSO. Of course it must also be substantially longer than any smoothing period that was employed. The temperature trace does not even need to be correct in absolute terms just reasonably accurate in relative terms time-wise. Apparently the importance of the change in direction of temperature trend is not recognized by those who do not understand how feedback works. Without significant net positive feedback, the GCMs do not predict significant Global Warming.
129591. Patrick 027 at 12:23 PM on 18 October 2008
        Volcanoes emit more CO2 than humans
        - started reading comments in "Arctic sea ice melt - natural or man-made?" - up to 119 so far... will return later...
129592. Quietman at 07:29 AM on 16 October 2008
        Volcanoes emit more CO2 than humans
        The link in 94 did not work. I think I put a slash after stm so heres a copy and paste version: http://news.bbc.co.uk/2/hi/science/nature/7081331.stm
129593. Quietman at 07:20 AM on 16 October 2008
        Volcanoes emit more CO2 than humans
        PS I suggest that you read this BBC November 2007 article as it does explain the skeptic attitude on this issue.
129594. Quietman at 07:09 AM on 16 October 2008
        It warmed before 1940 when CO2 was low
        The fact of the matter is that there is no actual evidence for the 30 years of warming attributed to CO2 to be anything other than natural. Our contribution, of various sources, not just CO2 is negligable. Most of the arguments presented against CO2 have some merit and the answer is most likely in the combination of all.
129595. Quietman at 04:49 AM on 16 October 2008
        Climate sensitivity is low
        Patrick You did start explaining your logic but diverted to an unrelated subject. While I did find your argument very interesting, I was not convinced that you actually proved Spencer incorrect. Actually, I have not read any papers or articles that show him incorrect, only alternatives. I view the IPCC alternative as incorrect because it has not produced the promised evidence in degree ie. Spencer has shown that his numbers equal observation while the IPCC numbers are way off from the observations. This is why their models don't work.
129596. Quietman at 04:45 AM on 15 October 2008
        Volcanoes emit more CO2 than humans
        Excuse the spelling, my attention is somewhat divided today with a sick grandson.
129597. Quietman at 04:44 AM on 15 October 2008
        Volcanoes emit more CO2 than humans
        Re: Your comments on plausibility. Yes the senate has even looked into the matter. If the scientist has a position like Spencer he can speak out, it's only reputation at stake. If the scientist is junior he can be fired or asked to resign. It has in fact happened. Polotical correctness is a disease of society that has been with us since the commie hunt back in the 1950s. That is why I said to read carefully. When a scientist skirts the issue it means that he/she does not agree but will not say so.
129598. Quietman at 04:16 AM on 15 October 2008
        Volcanoes emit more CO2 than humans
        Re: "Potentially so but only in a few locations, whereas the ice mass loss and general warming are far far far more widespread and general." Of those known or recognized at this point in time. All of these articles are findings after the IPCC had decided the cause was AGW. Re: "I think at least some of the articles you referenced did say that, not about some of the specific locations but about much of the other warming." Yes some cite AGW but without making it an argument (ie. it is assumed from the start). They did not look at the issue without the background assumption that it could only be AGW. Look at the facts, not the assumptions.
129599. Quietman at 04:09 AM on 15 October 2008
        Volcanoes emit more CO2 than humans
        Re: "Meltwater could come from the surface, flowing down into the glacier through moulins - this source would explain the seasonality of any meltwater-induced lubrication of the glacier. (Of course, however the ice is melted or induced to flow, the resulting thinning would lower the ice surface and cause warming of the ice surface that way.)" Agreed.
129600. Quietman at 04:08 AM on 15 October 2008
        Volcanoes emit more CO2 than humans
        Re: "Dark aerosols are/have contributed to arctic warming and melting in that way; that is true. tropospheric ozone has also contributed to Arctic warming and melting. So has CO2, CH4, etc. However, the highest albedo is from fresh snow. Old snow and ice tends to have a lower albedo." Agreed.

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