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Comments 41801 to 41850:

41801. Leto at 23:33 PM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Sereniac,

       The problem I have with that analogy is that the fitness training is not just a distractor that hides the true fitness signal, it leads to genuine improvements in fitness. The ENSO fluctuations do not lead to analagous true improvements in the global heat balance.

       What if your Mr Jones is becoming morbidly obese, and this can be accurately projected using a metabolic model, but his measured weight flucutates in the short term by as much as a 2kg (eating 2kg donuts, as he does at random times, inflates his apparent weight by 2kg).

       He visits the doctor immediately after a donut splurge, and posts a record weight (c.f. 1998 el nino). He then continues to eat excessively, but 15 days later, his next weight assessment happens to be just prior to his daily donut splurge. He has actually gained 1.5kg in weight, and is now posting a record empty weight (c.f. recent record la nina), but his measured weight is 0.5kg lower than the last measurement. He boasts that his weight trend is going down, and declares the doctor's metabolic model to be bogus. On the contrary, he is fatter than ever, and his next post-splurge weight is expected to break all records (c.f. next significant el nino).

       A plot of his post-splurge measurements shows no overall change in the post-splurge trend, as does a plot of his pre-splurge weights (c.f the separate el nino and la nina trends in the Neilson-Gammon plot), but the short term fluctuations in apparent weight mean that he often has pseudo-pauses in his relentless weight gain. The existence of such pseudo-pauses is entirely expected in the metabolic model, though the timing of the pauses is outside the scope of the model, and an ensemble of model runs will average out the pauses so that they are not apparent. Nonetheless, he uses the pauses as an excuse to continue his unhealthy lifestyle.

        

41802. bouke at 22:48 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       Thanks for the replies @5-7. Inspired by Kevins remark, I googled around some and found a nice explanation at the American Chemical Society.  

41803. OPatrick at 22:27 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       This is an odd statement, given that Curry had earlier quoted the IPCC discussing this issue prominently in its Summary for Policymakers:

       "Models do not generally reproduce the observed reduction in surface warming trend over the last 10 –15 years."

       Wasn't her point that this quote did not appear in the WG1 report? 

41804. Glenn Tamblyn at 22:01 PM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Interesting analogy Sereniac. One thing missing from it is the quantitave apart from words like 'dramatically'.

       Lets epand the analogy by saying the Mr Jones health indicators tend to rise by X when he trains for a fun run and decline by Y when has allergies. And his glucose problems cause a decline of Z per year. So how easy is it to detect Z in amongst X and Y? That depends on the relative magnitude of X, Y & Z.

       If X and Y are small, Z can be detected quickly. If they are larger, Z takes much longer to detect.

       Back to the ENSO issue. El Nino (X) and La Nina (Y) produce effects that can change average temperatures by +/- 0.1 to 0.2 Deg. This can mask global warming (Z) on time scales of a decade or so. But on multiple decades to a century, where global warming might cause temperature changes of 2-4 DegC (depending on what we do with emissions) then Z becomes very clear.

       Mr Jones' glucose problems become apparent when he can't engage in his training for the fun run because he is hobbling along with a cane.

41805. Dikran Marsupial at 20:47 PM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       chriskoz Essenhigh's 5 year figure for residence time is correct, and indeed agrees with the figure given in the IPCC WG1 report.  His error lies in not understanding the distinction between residence time and adjustment time.

       We should not be too hard on Prof. Essenhigh, his research record in his own field (combustion) appears to be very good, and it is all too easy to make this kind of error in moving into a tangentially related field.  The email correspondence I had with Prof. Essenhigh while writing my response published in Energy & Fuels was generally very cordial.

41806. chriskoz at 19:56 PM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       Essenhigh's 5y residence time number is bogus not only because it fails to consider the natural inflow (emissions from ocean/biosphere back to atmosphere) but also because, due to limited capacities of the natural sink such as ocean, the flow rates (determined by Henry's law) change over time.

       Only a part of CO2 molecules has a residence time of rougly 100y (a bit more than 75y calculated by vmin@8 but the same ballpark). In case of 1000GtC emissions, that part is some 50% - i.e. 500GtC of the original emissions being absorbed by the ocean surface results in OA reaching new equilibrium, therefore no more CO2 can be absorbed by Henry's law.

       The rest (500GtC) must wait for the deep water mixing and the reaction with sediments which takes 1-10Ky. Only 300-400GtC is taken that way, again due to limited sediment capacity.

       The rest (100-200GtC) must wait for the rock weathering processes which take sometime from 100Ky to 500ky (depending on current geological conditions).

       So, the residence time is not a simple constant number when we are dealing with such big amounts comparable to the natural sink capacity. In case of the emission scenarios considered in Anthropocene, it means 10 to 20% of emissions will stay in A for up to half a million years.

       Obviously, such science is well beyond Essenhigh, who makes very basic mistakes (i.e. ignores the inflow & Henry's law) that preclude any understanding of carbon cycle in geological sense.

41807. Kevin C at 19:55 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       It's also worth noting that land-ocean surface temperature records work with anomalies rather than temperatures, and thus they don't provide an absolute temperature against which to compare the models.

       BEST have addressed this, but their currently released data is land-only.

41808. Dikran Marsupial at 19:29 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       bouke, it is because the models do a much better job of modelling changes in response to forcings than in terms of absolute temperature (i.e. there are more or less constant offsets in absolute temperature between model runs).  For climate change research it is the response to a change in the forcings that is of interest, so the simplest thing to do is to apply the baselining procedure to eliminate these meaningless offsets.  Note also that if you want to perform a comparison involving both surface and satelite observations you have to look at the anomalies anyway as there is a big difference between absolute temperature at the surface and in the trophosphere due to the lapse rate.

       This is something well known to any climatologist that has worked with model output and is essentially uncontraversial, so it is somewhat surprsing that Curry and McIntyre are making a fuss about it.

41809. Dikran Marsupial at 19:23 PM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       vmin Residence time is defined as the mean length of time a molecule of CO2 remains in the atmosphere before being taken up by the terrestrial or oceanic reservoirs, so Essenhigh is correct in using the term residence time.  His error lies in not understanding the difference between residence time and adjustment time, which is the characteristic timescale with which the atmospheric concentration responds to a change in sources and sinks (which corresponds to your 75 year figure).  The IPCC define these differing definitions of lifetime in the glossary of the WG1 report, but unfortunately do not clearly distinguish between them in the report itself (although the 1990 report that Essenhigh cites makes the distinction very clearly).

41810. Marco at 19:12 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       Bouke, it is not about the vertical scaling, but about what point you use as a reference. 1990 as a single point is a bad reference, as it would be above the trendline. 1991 would be a bad point, too, as it is below the trendline. You should use a baseline *period*, which will eliminate much of the short-term noise. Whether you put that baseline as an absolute value or assing it to zero and put the other data as anomalies does not change any conclusions.

41811. bouke at 18:39 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       I am wondering, why are graphs always shown with temperature anomalies and not with the actual temperatures? That should remove any confusion with baselines.

41812. PJKs_shirt at 16:15 PM on 4 October 2013
       Skeptical Science now an Android app
       

       Any chance of porting the app to Sailfish?

       https://sailfishos.org/

41813. sereniac at 15:46 PM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       I've been trying to construct a layman's interpretation of the role of ENSO in AGW and came up with the following.

       Apologies for the level it is pitched at, but I'm grasping for a conceptual framework
        that most people can understand so that there is a better appreciation of the difficulties involved.

       Thanks for any feedback.

       __________________________________________________________________________

       A group of researchers only has access to a single individual: Mr Jones.

       The researchers are interested the phenomenon of aerobic fitness in Mr Jones and have a number of measures: resting heart rate and blood pressure, weight and BMI and time to complete a 5km treadmill run. Note that Mr. Jones is the only source of data and these measures can be obtained at any time, but there are no other research subjects.

       At the end of each year the average fitness of Mr. Jones is calculated as a combination of mean resting HR, BP and treadmill time.

       The researchers notice that Mr Jones has started consuming greater and greater quantities of drinks that are high in glucose. They are concerned that he will ultimately exhibit weight gain and loss of fitness even if the drinks may initially provide a short term energy boost when drunk. With weight gain comes obesity and chronic diseases.

       Hence the hypothesis is that excess glucose consumption will manifest itself as a decline in average aerobic fitness and especially weight gain/BMI, increases in resting HR and BP. If this is not avoided then chronic diseases such as diabetes, heart disease etc could be evidenced in another 30 or 40 years. That is the scenario to be avoided.

       It is a simple matter to measure Mr Jones’ annual aerobic fitness and as he continues to consume more glucose over say 15 years, his fitness appears to decline. Projecting this decline into the future suggests that in 30 years Mr. Jones will be obese, chronically unfit and with dangerous levels of BP.

       However, Mr Jones is also invited to a fun run about every 1-2 years. Mr Jones undertakes a serious course of training for each of these runs which vary in their distance and calendar timing. The runs can take any distance between 5km and 15km and although the runs happen roughly around the same time they can be advanced or delayed by many months. Hence the intensity and length of the training  cannot be predicted. But whenever Mr. Jones trains, his aerobic fitness dramatically improves. This fitness also lasts quite a while after the fun run.

       On the other hand, Mr Jones is also sometimes affected by  severe allergies. When this happens his activity levels drop dramatically. He can spend months doing very little at all and this diminishes his aerobic fitness a great deal. The timing of these allergies is roughly seasonal, but can happen early or late and in some years the allergies do not appear at all. In addition, while some years are very bad for his allergies, in some years they are evident, but quite mild. In short, Mr. Jones’ allergy reactions are roughly periodic but still unpredictable in timing and intensity.

       The task before us is projecting Mr. Jones fitness 30 years into the future when there is an evident trend of fitness decline with an increasing consumption of glucose drinks despite the fact that (a) Mr Jones fitness can improve from fun run training and (b) it can decline from allergies yet both cannot happen at the same time.

       Consider the situation where Mr. Jones appears not to be getting less fit yet over the same period he has been invited to a number of very long fun runs which required a lot of training. Can we still be confident that glucose is driving a loss of fitness?

       Also consider the situation where Mr Jones has shown a rapid loss of fitness but over the same period he has had a number of long and intense allergic reactions. Can we likewise be confident that glucose is driving the loss of fitness or is it just the effects of allergies?

       The situation is further complicated because Mr Jones is the only source of data. We cannot obtain information on the general role of excessive glucose consumption by measuring other people (they do not exist). Bu that would be very useful because the influence of fun runs and allergies would be more easily quantified- we would have varying timing and intensity of these influences on the fitness of many people rather than just one.
       
       

       These are some of the issues involved in projecting climate on the only planet
        you have.

        

41814. One Planet Only Forever at 15:07 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       It should be possible to statistically prove that the contrarians "conspire" to coordinate their "cross-selling". The tendency for them to mainly refer to claims made by each other could be evaluated statistically. This would then be evidence of their "conspiracy to misinform" by adding the evaluation of the validity of the claims they make and "cross-sell".

       The scam of using one person to say something that is then referred to by others as "proof" of something is even used by media groups like Fox News which will have one of their "speculators" say something then have their "News People" repeat the claim but frame it as something that "people are saying", when the only ones saynig it are the ones inside their operation hopng to get "others to say it".

41815. TonyW at 13:56 PM on 4 October 2013
       Lawson, Climate Change and the Power of Wishful Thinking
       Lawson is an idiot. What a shame, though, that his last sentence is almost certainly true (with high confidence).
41816. Tom Curtis at 13:52 PM on 4 October 2013
       CO2 is just a trace gas
       

       Bob Loblaw @16, your definition is non-standard.

       The best definition of the atmospheric greenhouse effect is the difference in upward longwave radiation at the TOA to that at the surface due to absorption and emission of longwave radiation be components of the atmosphere.

       Based on that definition, clouds contribute approximately 25% of the total current greenhouse effect, coming in behind water vapour (50%) but ahead of CO2 (20%).  (See link in my post responding to Undecided Molecular Biologist above.)

41817. Tom Curtis at 13:47 PM on 4 October 2013
       CO2 is just a trace gas
       

       Undecided Molecular Biologist @5 & 8, here is a spectrum of infrared radiation to space at the Top of the Atmosphere as calculated by the Modtran Model:

       

       The important points are:

       1)  The Earth's TOA black body radiation without a greenhouse effect would follow the shape of the coloured lines (black body radiation curves), with the specific shape depending on surface temperature;

       2)  The absorption of IR radiation from the below, and reemission at a higher cooler altitude results in a reduction in the TOA outgoing radiation, by the amount shown by the red shading;

       3)  The largest single factor in that reduction is H2O with absorption and reemission at wave numbers less than 550 and greater than 1300 (the initial dip around 1250 is due to methane); 

       4)  The second largest single factor in that reduction is that due to CO2 at a wave number of about 650;

       5)  The reduction to CO2 is almost as large as that due to H2O in a clear sky;

       6)  Although there is some overlap of H2O absorption and CO2 absorption, because CO2 is higher in the sky (as can be seen by its lower temperature of emission), it would have the same effect even in the absence of the H2O, so that the H2O has no effect in areas of overlap; and

       7)  The large CO2 absorption band is located near the peak of terrestial emissions allowing it to have a much larger impact than other absorbers.

       Modtran is only a model, so you may be disinterested in what it shows.  Such models have been compared with observations, however, and shown to be remarkably accurate.  An early such comparison was published in 1969:

       

       These and similar observations show that your parade of "corrects" are based on prejudicial thinking rather than on actually looking at the observational data on the issue.  Absent such prejudicial reasoning, it can be discovered that CO2 is responsible for approximately 20% of the all sky greenhouse effect. 

41818. Tom Curtis at 13:01 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       1) I believe that figure 2 (the trend comparison) would be improved by also showing the AR4 trend, using observed data for the years 1990-2000 (as AR4 projections start in 2001).

       2)  McKittrick did worse than simply eyeballing the trends.  Anybody with any experience in eyeballing trends could see from the draft figure that the trend for observations (and of AR4 plus observations from 1990-2000) would pass well below the 1990 point in the observations due to the large temperature excursion due to the Mount Pinatubo erruption.  In fact, had the draft report baselined the graph by ensuring all trends passed through the same point in 1990 (a perfectly reasonable procedure), that would have lifted the observations relative to the FAR, SAR, and TAR projections.  Indeed, sufficiently to place them in the upper half of TAR projections (from my eyeball estimate).  It would not have significantly shifted the them relative to an observations to 2000 plus AR4 due to the shared initial data.

       Because much of this shift would be due to the Mount Pinatubo erruption, that may seem like an unfair comparison.  To avoid that, the proper method is to use an extended baseline, as above, or to set the data for a common origin of trends having adjusted the data for short term factors not expected effect the long term trend, ie, something like this:

       

       

        

41819. sereniac at 12:44 PM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Thanks Bob.

       Unfortunately it is possible to obfuscate even the basic science unless it is codified in some form and the essential assumptions are clearly documented in a paper or analysis.

       For example, it is now required that all randomised control studies and other research reveal their power calculations as part of journal submissions. There are a number of assumptions underlying that as well and they can be questioned but it helps to quickly terminate papers that have insufficient statistical power to address the null hypothesis.

       I maybe naive because the depth of "declaration" of what is being assumed could
        include euclidean geometry being correct, but at least amongst the sophisticated
        scientists grappling with core issues, there could be a higher level and more
        explicit level of declared assumptions. And there could at least be a declared
        concensus or manifesto if you like of what are unchallengeable assumption underlying analyses.

       I am at least able to conduct a basic MLR and understand the judgements that
        apply, but it appears to me that in in addition to statistical treatment decisions, climate science often has very basic processes routinely questioned by people with
        the undergraduate (at least) training to know or know better.

       It is very confusing for outsiders in any field to judge the validity of arguments when credentialled people claim widely disparate conclusions based on very or mildly disparate assumptions.

       I really don't expect to read a paper where the mixing depth of oceans is disputed anymore than I expect a physicist to dispute the molecular weight of carbon or
        at least within agreed bounds.

       
       Thanks again.

41820. mikeh1 at 12:39 PM on 4 October 2013
       Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
       

       Ross McKitrick brilliant? I do not think so.

41821. Bob Loblaw at 11:57 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       sereniac: "there has not been open and transparent declaration and agreement on the basic assumptions behind basic positions."

       As you learn more, you will tend to find the following:

       - on what I will call the science side, there is pretty strong agreement about many of the basic assumptions. After all, a lot of the basics were worked out in the 1800s. (Yes, that is the 1800s. Not a typo.) For a look at this history, try this link. Scientists usually don't spend a lot of time discussing the basics that were agreed upon over 100 years ago. You learn them as an undergard, and move on.

       - on what I will call the "skeptics" side (although they are clearly not true skeptics), you will discover many mutally contradictory assumptions, which change with the shifting wind. They will assume whatever will lead to the conclusion they want, and then assume the opposite in another situation. Consistency is not a priority. If you follow the Arguments menu below the Skeptical Science masthead (at the top of every SkS page) to the Contradictions page, you'll end up here, where many of the "skeptical" contradictions are listed. The "skeptics" can't even agree amongst themselves what the basic assumptions are, let alone agree with the scientists.

       I take that back: the "skeptics" do have one fundamental assumption that is constant behind every argument: that the climate science is wrong. Everything else is malleable to fit that assumption.

41822. sereniac at 11:24 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Thanks for the Loehle/Scafetta critique.

       I have to confess that I really believe that a huge amount of the animosity and confusion associated with the AGW issue arises because there has not been open and transparent declaration and agreement on the basic assumptions behind basic positions.

       It is extremely frustrating for everyone to burrow through analyses only to find what SHOULD be a known physical fact being disputed e.g. depths of ocean mixing or whatever. Or CO2 solubility or whatever.

       I don't attribute blame disproportionatley here and it seems to me that all sides would achieve clarity and progress if these fundamentals were agreed to in some manifesto.

       That would at least provide a focal point where analyses could be dismissed outright because they did not adhere to assumption 3.4.3.1(a) or whatever.

       I realise this would be  very contentious exercise in itself and some would argue just as much work as the IPCC itself, but I have to be candid, as an outsider it is somewhat like  reading an orbital calculation where the altitude of the orbit is in dispute because of differences in judgements of what "counts" for the height of Everest.

       It's not just silly. It's ridiculous.

       Scientists should be able to reject that orbit because the height of Everest is agreed

       to be Xmm plus or minus whatever due to thermal expansions, storms or whatever.

        

       Really this seems to have become the ultimate case of apples and oranges.

       Sorry if I come across as frustrated- I'm sure many of you are as well and possibly

       exhausted by the number of apples you see counted as oranges.

        

       But truly, science just cannot progress efficiently without a clear declaration and

       agreement of (a) what is known and (b) what is assumed in the science of climate. Doing so must decrease the statistical uncertainties involved.

       I shall go back inside my box.

       
       Thanks again

41823. vmin at 11:12 AM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       I do not think that Essenhigh's calculation of the residence time is accurate. Majority of CO2 molecules absorbed by the ocean and vegetation are not removed permanently but returned back to the atmosphere. So the more appropriate analogy would be: 150 people are processed an hour form the 750 in queue. 140 of them are returned back to queue, thus only 10 are removed from queue. Consequently the real residence time is 75 years, not 5.

41824. sereniac at 10:10 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Damn

        

       Forgot the link. http://www.appinsys.com/globalwarming/SixtyYearCycle.htm

       thank you

       Moderator Response:

       [DB] Much of your link is addressed here:

       Loehle and Scafetta find a 60 year cycle causing global warming

41825. sereniac at 10:09 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Clearly there is a lot of variability in the quality of evidence and debate on the AGW issue.

       I have to say I have read a lot of unconvincing material on both sides of the argument.

       I also understand that there is a limit to which the intelligent layman can come to terms with this material. Yet some of us try and the better we're informed, the better the outcome for all of us- i hope.

       This site does at least reference some of the more respectable physics/scientific literature and is claiming I think the existence of a 60 years natural cycle which is driving climate behaviour in addition to GHGs, ENSO etc etc.

       I haven't backtracked to its home page since I would prefer to encounter the arguments on their merit and I have in the past been swayed in many directions based on my judgements of the ideoloogical commitment of a source.

       I would welcome any commentary on this. I have found the recent research convincing- that which identifies variation in ENSO hiding a long term warming trend.

       I suspect it is unlikely that mainstream analysts would have missed a 60 year cycle and I also suspect that this assertion is based on starting points (aren't they all?) as well,
        still I like to hear what people have to say and for me, the array of evidence appeared
        interesting, although again it may turn out to be selective.

        

       Thanks again

41826. sereniac at 09:56 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Thanks John.

       Maybe I phrased it wrongly. Perhaps these graphs show the ability of different models to reproduce *past* climate behaviour.

       If do, it would appear that a number are better than others.

       My question is therefore why not select those that match past climate the best,

       run those and thereby produce the projections.

       I don't understand the logic of retaining models that are poor in matching

       past climate.

       I suspect that a number of models that are poor in matching past climate have been retained because their assumptions are reasonable/logical and that even though they may not match past climate all that well, this may be a data problem and that
       *not* including them in the suite would mean that reasonable/known features of the climate would not be represented in the projections.

       Is that sort of it?

       Moderator Response:

       [JH] You have made numerous assertions without providing a single reference or citation to identify the source of your claims. Thus your assertions are nothing more than your opinions which do not carry much weight on this site.

41827. John Hartz at 09:27 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Sereniac #84:

       The climate models used by the IPCC are designed to make long-range forecasts. Unless we have a time machine, we cannot jump ahead to the year 2100 say and ascertain which sets of models are performing best.

        

       For the human race, there is no Planet B!  

41828. sereniac at 09:10 AM on 4 October 2013
       IPCC model global warming projections have done much better than you think
       

       Thanks for the commentary regarding the notion of La Nina as a negative feedback dampener of AGW.

       I have a question that has probably been asked many times before somewhere but

       have not found it answered.

       Q: When placed on a common graph, some models appear to be very poor compared to others. Why weren't these eliminated from the suite and the better models run more frquently? It would seem to me that this would tighten up the range of predictions.

       It just seems odd to me since my natural inclination would be to eliminate those models that don't seem to map onto actual climate behaviour very well.

        

       Thanks again

41829. Bob Loblaw at 07:19 AM on 4 October 2013
       CO2 is just a trace gas
       

       Undecided: "You both refer to mathematical "proof" that CO2 is indeed a "very active" substance via models."

       You have hand-waved away the effect of CO2 by using vague, ill-defined terms such as "not very active", "tiny absorption bands", and "very weak". Your "proof" is nothing more than an assertion.

       People are trying to point out to you that when you actually put numbers on "not very active", "tiny absorption bands", and "very weak", and do the math, the result says that the amount of CO2 in the atmosphere is actually important. It really does affect the radiation balance, and it really does increase global surface temperatures.

       You may think that handwaving trumps a mathematical calculation. Science generally takes the opposite view.

41830. Bob Loblaw at 07:10 AM on 4 October 2013
       CO2 is just a trace gas
       

       Robert: how do you define "greenhouse effect"?

       Clouds do asborb IR. But the greenhouse effect is traditionally thought of as the atmospheric effect where the atmosphere is transparent to visible sunlight, and relatively opaque to IR. Radiation from the sun reaches the surface easily, but is impeded on the way back out. As you note, clouds are not particualrly transparent to visible light. Thus, by my definition, they are not part of the greenhouse effect.

41831. Robert Murphy at 06:40 AM on 4 October 2013
       CO2 is just a trace gas
       

       #11:
       

       http://skepticalscience.com/argument.php?a=185#98478
       

       "The comment in Pierrehumbert's book refers to clouds (which do not contribute to the greenhouse effect)..."

       I was under the impression that clouds did indeed contribute to the greenhouse effect, though the total forcing from them is negative when you take into account the increase in albedo.  The cloud feedback due to temp changes is thought to be most likely positive, though that is not certain.  I do however understand that UMB misread
       Pierrehumbert, who as you say was talking about the uncertainty in the cloud feedback.  That's not true with the water vapor feedback, which we know is strongly positive. 
       

       
       

41832. ubrew12 at 05:47 AM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       "Prof David MacKay’s [3] highly readable Sustainable Energy: Without The Hot Air"  This link is not working.  I think it wants to go to: http://www.withouthotair.com/

41833. william5331 at 05:27 AM on 4 October 2013
       Lawson, Climate Change and the Power of Wishful Thinking
       

       Margaret Thatcher's use of climate change was not as pure as the driven snow.  She was trying to break the strangle hold that the coal industry had on Great Britain and climate change was one of her weapons.  Whether she was convinced of the reality of climate change or not is a moot point. 

41834. william5331 at 05:22 AM on 4 October 2013
       Lawson, Climate Change and the Power of Wishful Thinking
       

       An open letter to Mr Lawson

       Dear Mr Lawson

       Let's say for the sake of the argument that you are correct and this 15 year hiatus in surface warming will continue. Let's even say that the climate will begin to cool. Let us further agree that all the Ago floats have a calibration error and the missing heat is not going into the oceans. Let us even agree that sea level rise has stabilized and will continue at only about 3mm per year for the rest of the century. Even with all of the above, there remain so many reasons to wean ourselves off fossil fuels. I assume you receive none of your funding from the fossil fuel industry and your arguments come from a deep conviction. Have a quick glance over the following link.
       http://mtkass.blogspot.co.nz/2010/10/forget-climate-change.html

41835. CBDunkerson at 05:06 AM on 4 October 2013
       CO2 is just a trace gas
       

       UMB - Follow the logic train;

       1. Without atmospheric CO2 there would be no green plants
       2. Without green plants most animals would die
       3. Therefor, atmospheric CO2 can reasonably be said to have a 'large' effect
       4. Therefor claims that atmospheric CO2 is too small a trace gas to have any large effect are false
41836. Dikran Marsupial at 04:36 AM on 4 October 2013
       CO2 is just a trace gas
       

       Undecided Molecular Biologist: To get the discussion onto a more productive footing, do you agree that the theory of the enhanced greenhouse effect (see e.g. here for a brief explanation of the basic mechanism) that predicts warming as the result of increases in atmospheric CO2 is based on the recognised absorption characteristics of CO2 that you have mentioned?

41837. Dikran Marsupial at 04:20 AM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       BillEverett The link http://pubs.acs.org/doi/abs/10.1021/ef200914u works for me.  Hopefully the link in the article will be fixed shortly.

41838. Dikran Marsupial at 04:16 AM on 4 October 2013
       CO2 is just a trace gas
       

       undecided The comment in Pierrehumbert's book refers to clouds (which do not contribute to the greenhouse effect), not water vapor (which does), and so does not in any way support your earlier comments regarding H2O versus CO2.

       Pierrehumbert, like many climatologists, is perfectly happy to talk about the limitations of the models, however he are still willing to use them.  The fact that this is the case should give you pause for thought, that just perhaps you are blowing the limitations out of all proportion, and that perhaps you need to actually read the books and papers that explain how the models work, rather than just read the opening remarks until you find a comment that you can use to support your position.

41839. Composer99 at 03:46 AM on 4 October 2013
       CO2 is just a trace gas
       

       As a follow-up to my comment #9, I should like to add the following summary:

       The claims of denialists notwithstanding, the fact of the matter is, like any well-validated science, climatology is backed up by the three-fold combination of:

       (1) Theory - the known physics of radiative transfer, bulk heat transfer in the atmosphere & oceans, the radiative properties of greenhouse gas molecules, etc. etc. etc.;

       (2) Experiment - e.g. Tyndall's work in the 19th century, modern climate modelling, etc.; and

       (3) Observations - e.g. satellite era research showing the top-of-atmosphere energy imbalance, ARGO floats finding immense increases in ocean heat content, global cryosphere melt, and so on (and on and on...)

       I can assure you, Undecided, and any other readers, that the findings of climatology cannot be so easily tossed aside by casual references to bad financial modelling in the last decade: any attempt to overturn it has to come to grips with the theory, experiment, and observations.

41840. Composer99 at 03:36 AM on 4 October 2013
       CO2 is just a trace gas
       

       Undecided Molecular Biologist:

       There's nothing for it but to say that you appear to be operating with an extraordinary misconception of the underpinnings of climate science. Just imagine some random person coming along and spouting off completely off-base stuff about molecular biology. That is what your comment #8 looks like with respect to climatology.

       Climate models are emphatically not the underpinning of climate science. If anything, they're latecomers to the game. Climate science begins with the paleoclimatic studies of ice ages and the experiments of Tyndall in the 19th century, not with the hi-falutin' models discussed in IPCC reports.

       Our present understanding of climate and of greenhouse gases follows, of necessity, from the physical properties of greenhouse gas molecules themselves and their IR-radiative behaviour. As far as I am aware, these properties were more or less completely determined in the 1950s and 60s.

       The understanding that CO₂ is a critical forcing while H₂O is a feedback (that is, H₂O does not force climate changes, it can only amplify them) also follows of necessity from the same physical properties.

       What is more, we have access to empirical data from paleoclimate research and recent records-keeping, which we can use to validate modelling. As far as I am aware the bulk of empirical data strongly supports the mainstream understanding of climate.

       I have nothing to say about your attempt to draw an analogy between climate modelling and a particular set of financial modelling (if indeed you have characterized the latter accurately) or your final remarks, which IMO amount to issue-trolling, however well meant they may be.

41841. Undecided Molecular Biologist at 02:38 AM on 4 October 2013
       CO2 is just a trace gas
       

       You both refer to mathematical "proof" that CO2 is indeed a "very active" substance via models. This probably risks needing to move the subject to another thread, but to continue the point -
       Pierrehumberts book states very aggressively in his opening remarks, just one (of potentially thousands) of flaws in climate model calculations. Namely that water, or indeed clouds, pose a very severe challenge to the understanding of climate. One calculation error on either side of the effect clouds have upon radiative forcing, will destroy a model.
       When the number of interacting variables in a model reaches numbers that clearly climate science does, they have to be wrong, they will be wrong. Pure common sense says this. Indeed, you can back-model climate to check if you are right, but that is including the known variables. Bankers back-modelled AAA rated financial products 5 years ago. There was overwhelming consensus that they were right in their own (greedy-world) of peer reviewing each other’s work. Trillions were invested "risk-free".
       To model the risk profile of a AAA rated asset backed collection of securities is a piece of cake compared to trying to model climate science. And what happened?
       They were wrong. They missed a simple variable and the model broke. Trillions lost and global recession we are still feeling the effects of. Big mistake by an overwhelming consensus at the time and by (simple by comparison) models being wrong.
       I worry that the climate movement has made a grave mistake in backing CO2 as the driver of climate change....
       If it is proven to be a mistake, public will lose confidence and trust in the environmental movement and I fear even more important issues such as habitat loss, population growth, antibiotic use and sustainable practices will get effected.
       This is my big fear

       Moderator Response:

       [JH] You are now skating on the thin ice of sloganeering and excessive repititon -- both of which are prohibted by the SkS Comment Policy. Please cease and desist, or face the consequences. 

       [Rob P] Allcaps removed. See comments policy.

41842. BillEverett at 02:34 AM on 4 October 2013
       Residence Time and Prof Essenhigh
       

       The link in "Thankfully Gavin Cawley has now managed to publish a response, which should settle the matter (http://pubs.acs.org/doi/abs/10.1021/ef200914u)" doesn't work.

41843. kanspaugh at 00:02 AM on 4 October 2013
       Lawson, Climate Change and the Power of Wishful Thinking
       

       Agree with the comment that repetition is important to the rhetoric of denialism.  Recalls the strategy that Dick Cheney & Co. used to attempt to justify the US invasion of Iraq: "Lie; Retreat; Repeat.  Lie; Retreat; Repeat."   The difference is that global warming denialists don't much bother with the "retreat" part.  They just lie and repeat the lie.  They are that much more shameless.  

41844. Dikran Marsupial at 23:55 PM on 3 October 2013
       Residence Time and Prof Essenhigh
       

       BojanD/XRAY1061 The fact that CO2 levels have been increasing at a time anthropogenic emissions have been rising doesn't disprove Essenhigh's hypothesis, but the fact that they have been rising more slowly than anthropogenic emissions does (as Tom points out).

       The error usually made by these types of argument is to compare the gross volume of anthropogenic and natural fluxes into the atmosphere without considering the fluxes out of the atmosphere as well.  The rise in atmospheric CO2 levels is caused by the difference between total emissions and total uptake.  Anthropogenic emissions are small compared to natural emissions, but natural uptake is bigger still, and it is the difference between natural emissions and natural uptake that determines the natural comtribution of CO2 to the atmosphere (and it is negative!).

       FWIW Essenhigh's paper says very little about what is causing the rise in atmospheric CO2, just that it can't be anthropogenic because the residence time is short.  My paper explains why this is incorrect, residence time is short (4-5 years), but the conclusion does not follow.

       Anyone can make a mistake, however the NIPCC report cites Essenhigh's paper and uses similar arguments, that is a far more egregious error as the problems with Essenhigh's paper had already been widely discussed in climate blogs and in the journal itself.  It would ony take a google scholar search of the papers that cite Essenhigh's to have discovered that, which is basic scholarship.

41845. BojanD at 23:46 PM on 3 October 2013
       Residence Time and Prof Essenhigh
       

       Therefore the mere fact of the increase does not prove that the increase was anthropogenic.

       
       I think that's not what XRAY1961 had in mind. I think he meant that since Essenhigh implies (or openly states?) that anthropogenic contribution is negligible, then the source of rising CO2 concentrations should be huge and therefore not difficult to isolate. So I wouldn't go with 'completely disproves', but it gives it a lot of problems.
       
       It's astonishing that such faulty papers could get published. Beyond belief, really. I guess a college student could make such a mistake, but this ...

41846. DSL at 23:36 PM on 3 October 2013
       CO2 is just a trace gas
       

       UMB, what sort of "If by Whiskey" argument is that?  The relative strengths of the various greenhouse gases have been directly measured (example) from surface.  You know that, of course, and so I'm wondering why you're engaged in semantics when you could be going through the math.  If you want to talk about tiny changes, why not point out that if we use the full Kelvin scale up to the max GMST for the last 550 million years, a change of -3% results in a massive ice age.  A change of less than 0.2% resulted in the LIA.

       You might also check out this series of articles (the author welcomes feedback from those able to do the math).

       "reflector"?

41847. Dikran Marsupial at 23:01 PM on 3 October 2013
       CO2 is just a trace gas
       

       Undecided Molecular Biologist The basic mathematics of the enhanced greenhouse effect was worked out by Gilbert Plass back in the 50s, and the calculations were based on the "small" amount of the IR spectrum that CO2 actually absorbs that you mention.  The reason this can have a great effect is that the sun provides a very large amount of energy into the climate system, so (loosely speaking) you only need a small proportional change in the amount that escapes can have a big effect on surface temperatures.

       I suggest you get a copy of Pierrehumbert's book "Principles of Planetary Climate", and follow the maths, and you will find out how the greenhouse effect actually works and you will understand how important these small absorbtion bands are.

41848. Undecided Molecular Biologist at 21:11 PM on 3 October 2013
       CO2 is just a trace gas
       

       "Small amounts of very active substances can cause large effects"

       Yes.  But only if that substance is "very active".

       IS CO2 indeed "very active"?

       it only reflects IR "black body" radiation.  therefore is it not very active in terms of effecting heat, which spans a much longer band of wavelength than just bloack body IR.

       Even within the IR black-body band, CO2 only effects three tiny absorbtion bands that account for 8% of the "black body" wavelenths.

       Correct?

       If this is correct, CO2 is 100% not "a very active substance".

       Rather a better description is that it is a "very weak" reflector of heat.

       Correct?

       Water is a far more powerful green house gas both because of the level of heat it is able to reflect, but also the massive concentration of H2O in the atmosphere.

       Correct?

       back to CO2 - when you combine the fact that it seems to be a very weak reflector of the overall heat spectrum, combined with the fact it is present by concentration 0.03% of air, surwely the climate change movement might have made a massive mistake in placing CO2 as the central cause of global warming?

       ....when you heat water, it releases gasses including CO2, hence could CO2 in past warmings be an effect rather than a cuase?

        

       Moderator Response:

       [Rob P] Allcaps removed. Further transgressions will result in comment deletion.

41849. Tom Curtis at 21:04 PM on 3 October 2013
       Residence Time and Prof Essenhigh
       

       XRAY1961 @1, there have, in the past, been increases in CO2 concentration as large, and even larger than that (though probably not as rapidly).  Therefore the mere fact of the increase does not prove that the increase was anthropogenic.  Further, it is logically possible that the timing was mere coincidence - so while that timing is highly suggestive of the cause, it does not establish it to the standard scientists would normally accept.  Fortunately, there are at least nine other lines of evidence that, together, establish beyond any reasonable doubt that the rise in CO2 concentration is anthropogenic.

       Of these, one of the most important, and the one that Gavin Cawley most favours, is the mass balance argument.  We know that the CO2 increase was anthropogenic, because each year, the total increase in CO2 is less than we put into the atmosphere.  Therefore nature is taking CO2 out of the atmosphere each year, and consequently cannot have caused the rise in CO2 concentration.

        

41850. Trevor_S at 20:55 PM on 3 October 2013
       Secretary of State Kerry and Senator Boxer Remark on the IPCC Report
       

       William at @12

       "And yet, with a stroke of the pen, the politicians could have a profound effect on the problem"

       As could voters with a check of the correct ballot box or we emitters by not flying, travelling so much and by installing renewables.. and yet ??

       Professor Kevin Anderson (Tyndall Climate Centre) speaks to the latter here

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