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Comments 111801 to 111850:

  1. Can't We At Least Agree That There Is No Consensus?
    batsvensson at 00:38 AM on 25 August, 2010 no problem batsvensson; I suspect my post with slightly pompous actually! I think the essential problem relates... (i) .....a little to what you pointed out earlier; i.e. we have to be quite explicit about which specific element of the climate system and climate science we're referring to when we talk about consensus. ...and (ii) a little to the fact that much of what we know about the natural world has significant elements of uncertainty associated with it. So for example while there is probably quite a strong consensus amongst climate scientists that the climate sensitivity is unlikely to be less than 2 oC of warming per doubling of atmospheric [CO2] and also unlikely to be greater than 4 - 4.5 oC (without some poorly anticipated major positive feedbacks), and even that the most likely value is somewhere around 3 oC of warming.....you won't find any climate scientists (zero consensus) that consider that the climate sensitivity is 3 oC (per doubling of atmospheric [CO2]). So on most things (and especially those concerning future predictions/projections in the natural world), there simply won't be a "hard number" (just like there won't be a hard number in the prognosis of the survival time for someone diagnosed with lung cancer). Unfortunately uncertainty is something we have to live with and also understand and address maturely...
  2. Can't We At Least Agree That There Is No Consensus?
    JMyrphy wrote, "(fat chance, though, because you wilfully don't want to acknowledge the truth)" In what way does this claim (and similar claims you tend to do) support your argument? Is this to be regarded as a factual claim to be serious consider to support the "the truth" view? Can you explain what "the truth" is? Is "the truth" perhaps just a world view (of which some may work better than others – why is it then that other even thou they know "the truth" decided to opt for other less "better" truths)? The truth we have now is not the same truth that was around in the past, and most likely will not be the same truth in 500 years time. Science development has always been when the "truth" has been challenge, when people has broken with current thought and wisdom. Truth is very relative and maybe that should make us a bit more humble to knowledge because the guy next to you that disagree with you with "cray ideas" may be right, or (s)he may not. If one lean back on "the truth" and use that as the measurement stick then one will never be able to contribute with anything new or interesting to say. The point is, it is nobodies civil right to offend people just because they do not agree with common wisdom, the dissident may perhaps be an easy targets but that doesn’t change the fact that we perhaps should learn to be more respectful to each other. Perhaps with a respectful attitude towards each other a deeper understanding can be reached and in the end we may learn that we all been wrong. We know nothing, ands long we defend "the truth" we will learn nothing.
  3. Station drop-off: How many thermometers do you need to take a temperature?
    If your doctor tells you that you will die in six months, if you don't stop smoking. Do you: A. Throw your cigarettes away and never light another one. (the doctor spent years in school and training so they could tell you this). B. Get a second opinion. (being cautious is a good thing, but the other doctor confirms the first's diagnosis), so you still quit. C. Tell the doctor he's full of shit, and just trying to manipulate you! You've been smoking for decades with no problems, why all of the sudden there's a problem? Hah! D. Get a second opinion, that doctor tells you you only have 3 months to live. Since the two doctors can't agree to the precise time left to you, niether of them know anything, so you ignore them both. C and D seem to be the common choices made! Well, Climate scientists are also doctors, they also spent years in school and training, and they all agree (the real scientists, not creationist morons), that this global climate changes are at least partially if not entirely human driven. We have our second opinion, many in fact. We and our children will pay for our lack of confidence in our own scientists.
  4. Hansen etal hit a Climate Home Run -- in 1981
    factfinder - You ask where's the evidence for a greenhouse effect? Have you looked around on this site, or any others? Wiki on the greenhouse effect Radiative equilibrium Roy Spencer (noted skeptic) describing the GHE Another Spencer posting - "Cooler Objects Can Make Warmer Objects Even Warmer Still" Evidence for global warming Greenhouse effect with observed spectra Science of Doom gedankenexperiment on what would happen without the GHE (-18 C average temps) Introductory part-by-part overview of GHE There's tons more material out there, factfinder - this post was the result of ~90 seconds with Google. It's based on >150 years of spectroscopy, radiation physics, repeated observations, etc. Read up and enjoy the science.
  5. Medieval Warm Period: rhetoric vs science
    wrong link, here is the correct one: grosjean et al. 2007
  6. Medieval Warm Period: rhetoric vs science
    Alpine glaciers tongue response lags temperature by several decades and nevertheless the great aletsch retreat is already greater than at medieval times, however some area are in equilibrium with decadal temperature fluctuation and the ice cover there is smaller than at any times in the last ~5.000 years. grosjean et al. 2007 "The critical point in the context of this paper is that leather requires permanent embedding in ice in order to stay preserved and, as it is observed today, deteriorates very quickly if exposed at the surface. In consequence, the finds at Schnidejoch suggest permanent ice cover at that site for the last 5000 years, more specifically from ca. 3000 BC until AD 2003. At first glance our conclusion differs from the conclusions drawn from exposed trees in the forefields of melting glacier tongues (Jorin et al.,2006). However, the conclusions by Jorin et al. (2006; see also by Hormes et al., 2006) refer to the AD 1985 level:‘glaciers in the Grimsel [and Alpine] area were smaller than at 1985 AD during several times for the last 5000 years’; while our conclusion reads: ‘in the year of 2003 AD, the ice field at Schnidejoch has reached the smallest extent since the last 5000 years’. This is not a contradiction. We argue that this difference is explained by the dissimilar response lags of the two types of archives compared: ice mass balance near the ELA (Schnidejoch) responds immediately to sub-decadal climate variations, while Alpine glacier tongues respond with a multi-decadal lag to climatology (20–60 years (Jorin et al., 2006); importantly this fact also applies to the study by Hormes et al. (2006)). Differences between the equilibrium states of fast and slowly responding climate archives are typically large during phases of rapid changes. Indeed while the ice field at Schnidejoch is in equilibrium with the state of the atmosphere of the most recent years, the glacier tongues have not yet fully responded to the excessively warm years of the last 15 years, when (1) solar radiation at the Earth’s surface has increased owing to brightening of the atmosphere (globally 6.6 W mÀ2 10 yrÀ1 between 1992 and 2002, Swiss Plateau 7.2 W mÀ2 10 yrÀ1; Wild et al., 2005), (2) anthropogenic greenhouse forcing with related strong water vapour feedback enhanced the downward longwave radiation in Europe (þ1.18 W mÀ1 yrÀ1, data 1995–2002; Philipona et al., 2005) which increased temperatures, and (3) negative trends in the specific mass balance of Alpine glaciers accelerated (Zemp, 2006). "
    Moderator Response: Please don't paste such long quotes. Summarize, make the particular points of relevance, and provide the link. There is no hard and fast rule about how long is too long, just a rule of thumb that if readers can easily click a link to see some text, give them that link with instructions of where to look once they get there.
  7. Medieval Warm Period: rhetoric vs science
    Well, if you had a few hundred years of hot climate you would have trees much higher than those in MWP. However, trees have yet to go up. This is a long process but it is documented to be ongoing.
  8. Hansen etal hit a Climate Home Run -- in 1981
    the sigmas are the Standard deviation of the data. An envelope of plus/minus one one sigma includes most of the date +/- 2 sigma is almost all data. In Statistical process control, the term "six sigma" is used (from IBM) to denote the ultimate goal of SPC that application is the inverse of this application as instead of expanding your data pool, it narrows it, which means no variation in output test criteria. Climate researchers have been sounding the alarm for 60 years. If you look at the global temperature data, I can see the effects of both world wars (second more than first) as well as the great depression! That tells me that we humans do have an effect on global temps.
  9. Can't We At Least Agree That There Is No Consensus?
    @Tom Dayton at 06:41 AM on 24 August, 2010 You seams to be referring to epistemology now, but I am not sure how you means this would be related to consensus in this case?
  10. Can't We At Least Agree That There Is No Consensus?
    @chris, at 07:04 AM on 24 August, 2010 Remember that words/definitions are shorthand signifiers for the things they describe. They are not the thing itself Ah, right. Thanks chris for the brief clarification and help sorting out my own confusion there. Apparently I got myself mislead with which labels should be attached to which description there. “balance of evidence” has nothing necessarily to do with climate models, It is not my intention to suggest the contrary. What I mean with hard evidence is, just as a wrote, something you get from an observation, i.e. a number.
  11. Hansen etal hit a Climate Home Run -- in 1981
    Where is the scientific experiments and data proving the existance of the "Greenhouse gas effect" Hypotheses are fairy-tale until we see experimental data. This paper is more circumstational evidence if its true.
    Response: "Where is the scientific experiments and data proving the existance of the Greenhouse gas effect?"

    The greenhouse effect has been directly measured for 50 years. Planes measuring the upward spectrum from 20km up find big "bites" taken out of outgoing radiation by greenhouse gases. This is confirmed by surface measurements that find corresponding extra radiation returning to Earth at those same greenhouse gas wavelengths:

    IR spectrum at the North Pole

    Of course, you might be asking about the increased greenhouse effect. Eg - is rising CO2 levels causing an increase in the greenhouse effect and hence causing global warming. This is also directly observed by independent measuring systems: both satellites and surface measurements find less infrared radiation escaping to space and more radiation returning to Earth.


    Change in spectrum from 1970 to 1996 due to trace gases.
  12. Arkadiusz Semczyszak at 00:25 AM on 25 August 2010
    Medieval Warm Period: rhetoric vs science
    NH - MWP - or wants to Mann and Briffa - MCA. It's probably Spenser said: there was no MWP warmer than today? So it (probably) early medieval skeptics planted these trees, whose trunks are revealing Alpine glaciers, Alaska and Greenland ...
  13. What caused early 20th Century warming?
    muoncounter #35 In the absence of any anthropognic forcings prior to 1750AD, the only climate driver would be the various Solar cycles including the 11 year cycle, and multiple overlapping orbital cycles which have varied the Earth's exposure to the sun. Volcanic cooling is transient and significant in short bursts, but being randomly distributed in time cannot be counted as part of a natural forcing cycle. The Earth is most probably never in equilibrium, but if you are trying to separate and quantify the effects of CO2GHG forcing - you must be able to accurately tell us where we are in the cycle of 'natural' solar forcing. In 1750AD the Earth was warming out of the LIA but this says nothing about whether Solar forcing was above or below the 'midpoint' of the natural oscillation in 1750AD. If you look at the time series forcing curves for warming and cooling forcings, the positive areas under the curves indicate the total energy added to the earth system and the negative areas the energy subtracted from it. These theoretical AG forcings are baselined about a zero axis. eg. in 2005 CO2 forcing was posed at 1.66W/sq.m and total aerosol cooling at about -1.2W/sq.m (ref Fig 2.4 AR4). If you are going to add Solar forcing into this mix you also need a zero axis baseline so the forcings can be added or subtracted correctly. Is not a zero basline for Solar the 'equilibrium' TSI where in the absence of AG forcings (pre 1750AD) the Earth was 'in balance'? We had a Solar maximum up to 1960 and a slow drop off in TSI since then (ignoring the 11 year cycle which oscillates on top of the basic Solar forcing signal). The total energy above the 'zero baseline' has to be in the system somewhere to obey the first law. Land and atmosphere has tiny storage capacity compared with the oceans which has thermal lags (depending on depth) of 10's to hundreds of years. Heat stored in the oceans can be exchanged with the atmosphere and land in complex circulations and cycles (ENZO, AMO etc) Unfortunately, the measurement of OHC is unable to track this heat with current technology despite the greater coverage of Argo, and the purported forcing imbalances are not showing up in the oceans above or below 700m more than about 60% of the theoretical amount of 0.9W/sq.m and even this is in doubt. Small OHC increase means small imbalance over time, and small imbalance could mean Solar forcing only or a smaller CO2GHG effect that theoretically claimed.
  14. What were climate scientists predicting in the 1970s?
    In addition to the paper that gp2 cites, there was also a 2006 Science paper (Ramaswamy et al. 2006) that addresses this stepwise pattern. From the abstract: Observations reveal that the substantial cooling of the global lower stratosphere over 1979–2003 occurred in two pronounced steplike transitions. These arose in the aftermath of two major volcanic eruptions, with each cooling transition being followed by a period of relatively steady temperatures. Climate model simulations indicate that the space-time structure of the observed cooling is largely attributable to the combined effect of changes in both anthropogenic factors (ozone depletion and increases in well-mixed greenhouse gases) and natural factors (solar irradiance variation and volcanic aerosols). The anthropogenic factors drove the overall cooling during the period, and the natural ones modulated the evolution of the cooling.
  15. What were climate scientists predicting in the 1970s?
    The stepwise cooling is explained here: Thompson et al. 2009 Also note that expected greenhouse gases cooling in the lower stratosphere is much lower than the observed trend: "The resulting analyses reveal that the distinct drops in global-mean stratospheric temperatures following the transient warming due to the eruptions of El Chichon and Mount Pinatubo are linearly consistent with con- current drops in ozone. We note that the several-year period after the eruption of Mount Pinatubo is unique in the global ozone record, insofar as it is the only pe- riod in which concurrent ozone decreases are observed across, not only the tropics and NH midlatitudes, but also SH midlatitudes. The analyses further suggest that the weak rise in global-mean temperatures between the eruption of El Chichon and Mount Pinatubo is consis- tent with the concomitant weak rise in ozone, and the results clarify that the seemingly mysterious rise in global-mean stratospheric temperatures since ;1993 is consistent with increasing stratospheric ozone juxta- posed on global-mean cooling of ;0.1 K decade.
  16. Berényi Péter at 23:15 PM on 24 August 2010
    What were climate scientists predicting in the 1970s?
    #44 Ned at 22:59 PM on 24 August, 2010 it seems to happen in a curious stepwise fashion Steps are synchronous with major volcanic eruptions.
  17. What were climate scientists predicting in the 1970s?
    BP writes: The layer of stratosphere channel TLS (57 GHz) is sensitive for may be too low (peak sensitivity at 17 km), the divergence grows large only above it. Do we have upper stratosphere temperature time series? That is exactly one of the things I was skeptical about in your chain of reasoning, given that the trends at different heights in the stratosphere are quite different (at higher altitudes CFC-associated ozone depletion also complicates the analysis of temperature trends, something that wasn't anticipated in 1967). See Randel et al 2009, fig. 19: Figure 19. Vertical profile of temperature trends for 1979–2005 derived from each of the individual SSU and UAH MSU4 satellite data sets, averaged over 60°N–°S. Vertical bars denote the approximate altitude covered by each channel, and horizontal bars denote two-sigma statistical trend uncertainties. Results are also shown for trends derived from radiosonde data averaged over 60°N–°S. The solar cycle also has a much stronger impact on stratospheric temperatures. The data from the mid to upper stratosphere are not as reliable as those from the lower stratosphere, for a number of reasons. They do show strong cooling (around 0.5C/decade in the middle stratosphere, even more at higher altitudes), but it seems to happen in a curious stepwise fashion that I'm not sure anyone has completely explained: Figure 18. Time series of near-global average temperature anomalies derived from SSU data, for each individual channel (as noted). Data for channels 26x and 36x are shifted for clarity. I am agnostic about the causes of that stepwise downward pattern. I wouldn't be surprised if it turned out to be partially due to an interaction between the CO2-induced cooling trend, stratospheric ozone, and the 11-year solar cycle (which as mentioned above has a stronger effect on stratospheric temperatures). On the other hand I also wouldn't be surprised if it was partially due to problems with the intercalibration of different SSU sounders on different spacecraft. Given all the uncertainty in the SSU record, I have generally been reluctant to draw much in the way of conclusions about temperature trends there, other than that they superficially seem to be more or less in agreement with what we expect. Randel et al. (2009) and Shine et al. (2008) seem to be very relevant (and very readable).
  18. Berényi Péter at 22:20 PM on 24 August 2010
    What were climate scientists predicting in the 1970s?
    #42 Ned at 19:24 PM on 24 August, 2010 sources that can be cited a bit more directly than your convoluted chain of telephony here Here is the original Manabe paper. Vol. 24, No. 3 Journal of Atmospheric Science, May 1967, pp. 241-259. Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity Syukuro Manabe and Richard T. Wetherald Fig. 12 (Vertical distribution of radiative convective equilibrium temperature for various values of water vapor mixing ratio in the stratosphere) and Fig. 16 (Vertical distribution of temperature in radiative convective equilibrium for various values of CO2 content) show a possible cause. The layer of stratosphere channel TLS (57 GHz) is sensitive for may be too low (peak sensitivity at 17 km), the divergence grows large only above it. Do we have upper stratosphere temperature time series?
  19. There's no empirical evidence
    Moderator, If you're going to shut down the ability to post to a thread, can you please notify the audience? Thank you
    Response: There is no feature to shut down posting on any thread. If your comments are not immediately appearing, just check that the number of comments isn't just over the 50 or 100 mark (or some other multiple of 50). Your comment might be appearing on the next page over. Or if it appears then is removed, it would be because its violating the comments policy.
  20. Arctic Sea Ice: Why Do Skeptics Think in Only Two Dimensions?
    Agnostic #9: Actually, extent does not DIRECTLY relate to albedo. Ice extent is the area of OCEAN containing at least X% (usually 15%) sea ice. So, an extent of 100 sq km might only have 15 sq km of actual ICE area. That said, there are actual ice AREA estimates as well and those are obviously relevant for albedo purposes. However, I still think volume is the most important factor to keep an eye on. If it continues dropping at the rate it has the past few years (unlikely) then we're only three or four years from all the ice being gone. More plausibly volume declines will level off in the next year or so once all of the multi-year ice has melted down to basically the same thickness as 'first year' ice. It'll be interesting to see how quickly that leads to the breakup of the mass of multi-year ice along the northern Canadian archipelago (the western fifth is already gone) and what that will do to Arctic currents and ice export.
  21. Station drop-off: How many thermometers do you need to take a temperature?
    @gallopingcamel As I understand it. Nobody droped volontary 80% of the station. Essentially, validation process is long and tedious. You need time, manpower and computation capability to do that. Actually, a new version of the database is about to be released. This shoould close the gap. Expect an upward revision of the temperature change. This will certainly creates new claim of manipulation by skeptics.
  22. Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
    Published in the Journal of Cosmology. This is a dump for crappy idea, whatever if the field of research. "Warming on Mars must therefore be real and be a result of a complex (including magnetic) solar activity (f. e .QBO). " This is a very farfetch idea that provide a lot of information about the structure of your logic. We have only a very few data point for Mars temperature. Also, I dont see any commun mecanism that could be invoke the have a comparable effect on MArs and Earth. In addition, in the observation perio, solar activities as gone done. In addition, nobody claim than Sun has no impact on climate. However, even the most supporting analysis claim that it cant exceed 50% and is much likely to be below 25% of the observed warming.
  23. Medieval Warm Period: rhetoric vs science
    Ned, you are right. The bare minimum is to have a cycle with the length of the data span. This work only without any confonding factor. Maybe the thousand tears cycle comes from other data.
  24. Pakistan flood: many more will die unless more aid is delivered quickly
    Kernos #10: Did you not read any part of my comment except the last sentence? Killing off a few billion (or "thousand million" as you put it) non-industrialized farmers would not help slow global warming EITHER. They aren't the ones causing CO2 levels to increase. China and India have long had huge populations... but their CO2 emissions were virtually non-existent until they began to industrialize. The vast majority of their populations (in rural areas) still emit little CO2. Wiping out all of the Americas, Europe, and industrialized portions of Asia (your 'few billion' people) would have a major impact on global warming from CO2 emissions. But those areas have much better disaster preparedness and simply will not suffer those kinds of losses. The only places you get huge population growth and massive deaths from natural disasters are in poor rural areas which aren't contributing to CO2 emissions in any significant way. So again... no significant 'negative feedback' on CO2 emissions from natural disasters. At least not any time in the near future. Go out a hundred years or more and it might be a different story... depending on how much CO2 we've emitted and how well technology has kept up with allowing us to adapt to the climate.
  25. Hansen etal hit a Climate Home Run -- in 1981
    Nice timing. Tom Fuller and others over at Bart's place are criticising Hansen for a supposed comment that he made about the West Side Highway being flooded today due to sea level rise in a Salon Magazine article. Fuller goes on to claim that Hansen has been discredited along with Dr. Mann. Going there now to post this link. Touche'
  26. Arctic Sea Ice: Why Do Skeptics Think in Only Two Dimensions?
    I second the comments at #9. And also the concern for whether this post will date quickly (especially since it already refers to April and it is August). I thought basic level explanations were generally not going to include links to papers. Furthermore, I wonder about the register of "metric" and "satellite radar altimetry" in a basic level explanation. I think Graham does a great job, but a couple of improvements are possible in this one.
  27. Can't We At Least Agree That There Is No Consensus?
    Poptech wrote : "Pielke Jr. made no request to remove papers..." Maybe if I copy and paste his words again, you might understand Pielke Jnr this time (fat chance, though, because you wilfully don't want to acknowledge the truth) : A quick count shows that they have 21 papers on the list by me and/or my father. Assuming that these are Hypothesis 1 type bloggers they'd better change that to 429 papers, as their list doesn't represent what they think it does. Roger Pielke Jr's Blog - Better recheck that list Poptech wrote : "I never said Pielke Jr. asked for his papers to be removed (period)." And now you are getting very confused. You never said that because you cannot acknowledge the truth, i.e. that Pielke Jnr himself asked that (SEE ABOVE). There should be no confusion about that and the only confusing part is how YOU can be confused by that. Then again... Poptech wrote : "Everyone knows what my extensive list represents as it is explicitly defined, The following papers support skepticism of AGW or the negative environmental or economic effects of AGW." Only you know what your little list is all about and how you can square the circles of including those authors who have told you that their papers are not what you claim them to be. Only you can see skepticism in strange places that don't contain any. Only you. As regards your description, you leave out the word 'alarm' but include it in your title. More confusion on your part, it would seem. Do the "following papers" show skepticism of AGW 'alarm' (in your own mind, of course), or don't they ? If they do (in your own mind), why don't you state as such in your introduction ? Maybe it doesn't matter because you know what you are going on about, even if no-one else does ?
  28. NASA-GISS: July 2010-- What global warming looks like
    Pete Ridley writes: Between ice ages the globe warms and glaciers retreat then cools and glaciers advance. It’s happened before and will happen again. Right. But you don't get a glacial/interglacial cycle of that magnitude based on Milankovich forcing alone without a CO2 feedback amplifying it.
  29. Medieval Warm Period: rhetoric vs science
    muoncounter, thanks for the comment, but I find this a bit hard to swallow: "Yes, there is an underlying long term 'natural cycle', with an apparent period of 1100 years. " I don't think one can confidently diagnose the existence of an 1100 year periodic cycle from 2000 years of data unless the repetition is very, very close to exact. That's less than two full cycles!
  30. What were climate scientists predicting in the 1970s?
    BP writes: either something was fundamentally wrong with a model leading climate scientists relied on in the mid 1970s or our temperature measurements are flawed [...] You say it was the model [...] Please. This is the second time recently that you have put words in my mouth that I do not say (see also here). I generally choose my words carefully here and would appreciate it if you would not rearrange them to suit some rhetorical game of your own. BP writes: Either ... or. There is no third possibility. It's plain logic. A third possibility would be that your interpretation of Manabe via Schneider & Coakley via Schneider & Dickinson is incorrect. It's not exactly like no one has thought about the radiative-convective fluxes between the troposphere & stratosphere since 1974. I haven't heard any concern that the calculated MSU TLS temperature trends are in deep irreconcilable conflict with atmospheric models. Maybe people are really concerned about this, in which case I would assume there would be references to it in the literature post 1974, and in sources that can be cited a bit more directly than your convoluted chain of telephony here.
  31. Station drop-off: How many thermometers do you need to take a temperature?
    You have left out steve mosher. Credit where credit is due....
  32. There's no empirical evidence
    Johnd @ 152 - "If variations in solar radiation was the sole means by which the rate of gain varied, what were the processes that adjusted the rate of loss?" Just call it an exercise in deductive reasoning
  33. Pakistan flood: many more will die unless more aid is delivered quickly
    Pete Ridley, which GCM's project a long term cooling trend with increasing greenhouse gases?.
  34. Hansen etal hit a Climate Home Run -- in 1981
    John Brookes, but then they go on to assure us there's nothing to worry about (?), so it balances out.
  35. Station drop-off: How many thermometers do you need to take a temperature?
    gallopingcamel #4 "Real scientists gather every bit of data available and only discard data for good reasons." This is incorrect. Real scientists will use the principle of parsimony to ensure that the data they can deal with is both accurate and manageable.
  36. Of satellites and temperatures
    NOAA do not use anymore AVHRR data for sst since july 2009, they excluded avhrr data because of a cold bias in the middle and high latitude Southern Hemisphere where in situ data are sparse: ersstv3 Before that avhrr data were inter-calibrated using ship and buoy data and cloud/aerosol contamination removed.
  37. gallopingcamel at 16:04 PM on 24 August 2010
    Station drop-off: How many thermometers do you need to take a temperature?
    The arguments of the statisticians boil down to the hypothesis that the result was not changed by omitting ground stations in high latitudes and high altitudes. As I have pointed out several times before, that is not the point. Can anyone tell me why it makes sense to prune over 80% of the ground stations? Real scientists gather every bit of data available and only discard data for good reasons. NASA, NOAA and the rest have discarded the vast majority of the data without bothering to explain why. Take a look at Peterson & Vose 1997 (An Overview of the Global Historical Climatology Network Temperature Database). While P&V are up front about dropping many ground stations they don't tell us why. I have emailed these good people but they don't respond.
  38. Hansen etal hit a Climate Home Run -- in 1981
    The skeptical take on this, of course, will not be that Hansen et al understimated warming. Noooo. They will just say, "See, Hansen was wrong again."
  39. Hansen etal hit a Climate Home Run -- in 1981
    Bern, my impression is that the IPCC predictions are indeed conservative because of the requirement to reach consensus, which has the result that the most contrarian (philosophically and or economically) member nations force down the predictions so as not to frighten their own populations into asking questions about their policies.
  40. Hansen etal hit a Climate Home Run -- in 1981
    Thanks for the article, muoncounter. Every one of these "what did scientists predict decades ago" articles I read seems to tell the same story - climate scientists have generally underestimated temperature rise and potential climate impacts. The question I would then ask - are the predictions now being published similarly conservative, or has the methodology changed to be more 'accurate'? It seems the IPCC AR4 predictions are conservative, which may be a cause for concern as authorities are basing long-term planning decisions on those predictions (particularly the sea level rise ones).
  41. Can't We At Least Agree That There Is No Consensus?
    kdkd -- that's true for me. I looked through the list and the arguments. PT has zero credibility for me. Not worth wasting time on. Indeed, after my look, I can't even believe that PT is attempting any real engagement with the science. It seems more of a rhetorical game designed 1) to fool people who don't have time to look into to the details and 2) to waste the time of those who might want to actually move forward. Zero integrity, based on the overall evidence of the postings, or else an integrity tied to a different goal--a goal that has nothing to do with science.
  42. Hansen etal hit a Climate Home Run -- in 1981
    Good post ! :) The link for the 'critically reviewed' paper mentioned at the bottom of the post is not working.
    Response: Hmm, that link seems to have disappeared into the ether. I've updated it, linking to http://www.skepticalscience.com/Hansen-1988-prediction.htm (muoncounter, if that wasn't the page you were linking to, feel free to update the post).
  43. Station drop-off: How many thermometers do you need to take a temperature?
    It might be instructive to explain that stations were not really dropped. Rather the Global Historical Climate Network (GHCN), which collects and provides the raw temperature data to the other institutes, was built in ~1992 from retroactive climate records. GHCN doesn’t have resources to manually add millions of data points on an ongoing basis, so they sort of put the GHCN on autopilot thereafter, to receive CLIMAT reports electronically (for surface stations) but the database is supplemented by other sources. It’s largely up to national met agencies which stations they put on the CLIMAT system and how regularly each station sends data. Perhaps 20% (?) of stations automatically feed into GHCN. I suppose at some point they will add some or all of the accumulating manual records.
  44. Hansen etal hit a Climate Home Run -- in 1981
    #1: "we need to explain what '1sigma' and 'temperature anomaly' mean" Sorry, I thought that 'temperature anomaly' was standard terminology; just about every temp graph you see (including the one in the original Fig 7) is delta T = T - (some average T). As for 1 and 2 sigma, I'm sure subsequent comments will take care of that. BTW, I stumbled on this paper after reading the 'What were climate scientists predicting' thread.
  45. Hansen etal hit a Climate Home Run -- in 1981
    O-o-o-o-K-k-k-k-k, so when we write up a 'basic' version of this, we need to explain what '1sigma' and 'temperature anomaly' mean. The latter in particular has a somewhat surprising technical sense, differing from the sense you would expect by combining 'temperature' and the usual meaning of 'anomaly'.
    Response: Bit of "intermediate whiplash", I see, after all those Basic posts :-)

    There's no plan to write basic versions of every blog post. We're only writing basic versions of the rebuttals of skeptic arguments. Fair point though, even intermediate posts should explain the technical terminology.
  46. Arctic Sea Ice: Why Do Skeptics Think in Only Two Dimensions?
    To be fair it's not just skeptics that favour extent and area it's the scientists themselves. Every online website from polar groups seems to have it's own measure of extent. In fact PIOMAS ice volume graph you show is a fairly unique online metric from my trawling. While PIOMAS seemed accurate before 2007 there does seem to have been a deviation between their modelled results and reality since. In 2008 and 2009 this model underestimated the minimum extent and looks like it will again underestimate extent. Surely a model is always under scrutiny going forward, this is the best test for how well it is modelling the real world, at what point do we say that a model is no longer accurate. It seems that continually referring back to 3 years when it matched well with a short satellite data set can't be enough to keep it afloat. There are still issues with ice thickness measurements specifically the lack of good spatial and temporal coverage which leaves uncertainty in any estimate of volume or trends. Looking back to the 1990's here's two papers covering that period which came to very different conclusions (Windsor and Rothrock). More recently I just read this paper Thickness sensitivities in the CICE sea ice model Elizabeth C. Hunke Ocean Modelling Volume 34, Issues 3-4, 2010, Pages 137-149 which suggests that the probable number of factors which affect ice thickness out-numbers the data sets by which those factors can be constrained suggesting we still don't have the data by which we can directly or through models accurately estimate thickness and more importantly trends. It seems there are good reasons why some are cautious about ice thickness. Why not highlight the uncertainty associated with this particular metric? It seems like an important aspect of the work. (Just for correction the Giles 2008 and Kwok 2009 only seem to cover 2008 data not 2008/2009 as you seem to suggest in your article. You've also managed to leave out the word modelled with regard to the PIOMAS graph.)
  47. Arctic Sea Ice: Why Do Skeptics Think in Only Two Dimensions?
    Surely both measurements are important for different though related reasons. Decline in volume causes average thickness of sea ice to diminish and the speed with which it melts, so it effects the duration of ice cover. Decline in the extent of ice cover reduces its effectiveness in reflecting solar energy back into space, limiting ability of the Arctic Ocean to absorb it. It is the latter aspect we should be concerned about since loss of the albedo effect means that solar energy absorbed by seawater is gradually increasing, warming that water, further reducing the thickness, extent and duration of sea ice cover.
  48. Can't We At Least Agree That There Is No Consensus?
    Poptech #60 "It is clear you are very concerned about anyone reading my list, which is why you spend so much energy unsuccessfully attempting to discredit it." On the contrary, I think you'll find for any serious person your list of papers is thoroughly discredited. The show stoppers for me are: 1. You don't really understand what peer review means. 2. You don't understand how jouranl quality is assessed. 3. You don't understand the importance of citations. 4. Finally you don't differentiate between political, economic and scientific work. It's just a very long list with no attempt at any critical analysis. Your list of papers is really irellevant to the scientific consensus for these reasons.
  49. Arctic Sea Ice: Why Do Skeptics Think in Only Two Dimensions?
    #7: "skeptics think in 2 dimensions because they never saw the movie." That's a hoot! But we should be thankful: 2 dimensions is better than the usual one D thinking that you see all over denier sites about the IARC-JAXA graphs. "The decline in extent during July (i.e. the June 30th extent minus the July 31st extent) was uncommonly low." See, you can make a silk purse out of a sow's ear.
  50. What were climate scientists predicting in the 1970s?
    BP #40 "No. I just wanted to point out either something was fundamentally wrong with a model leading climate scientists relied on in the mid 1970s or our temperature measurements are flawed." You're going to have to spell it out unambiguously. What do you mean by "something"? Vague insinuations are not good enough, please be more specific. And just for good measure, remember that your recent posts are contaminated with language showing that you consider your preconceptions more important than the actual evidence (e.g. overstating hypotesis as findings). So if you want to be taken seriously, I suggest that you are very very careful indeed with the way that you explain what this "something" could be.

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