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Dikran Marsupial at 02:34 AM on 4 June 2014There's no empirical evidence
Just to add to KR's comment, if you look at a comparison of the AR4 SRESA1B model ensemble with the observations (courtesy of RealCLimate):
you can see that the observations were further into the upper tail of the envelope of model runs than they are into the lower tail of the distribution in recent years.
Now, ask yourself why the skeptics were not interested in pointing out the model observation "inconsistency" in 1998. Cherry picking indeed, the 1998 one clearly wasn't ripe. ;o) -
KR at 02:19 AM on 4 June 2014There's no empirical evidence
Razo - WRT Von Storch and the avoidance of ENSO effects on trends, it is notable that: if you select as an endpoint an extrema value from a time series, the statistical significance of anything terminating there is much much lower.
There's a good discussion of this over on Tamino, under Cherry-p. Von Storch followed in the trail of many a pseudo-skeptic, and selected the 1998 El Nino (3-sigma in scale) as one of his trend endpoints. Without noting the fact that it was indeed a time series variation extrema.
In the presence of such selection of an extrema, the required p-value for statistical signifcance can be 10x normal!! That's because in any system with noise you can find short trends up and down, meaning once you start selecting extrema endpoints, you need far more supporting data to make your claim(s). Supporting data that simply doesn't exist in the temperature record.
1998 trend claims are the essence of cherry-picking, of selecting a subset of data that appears to support a claim while ignoring the remainder of the data that contradicts that claim. It's a "fallacy of selective attention, the most common example of which is the confirmation bias", and such claims are logical fallacies.
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edaaaa at 01:28 AM on 4 June 2014Antarctica is gaining ice
I simply ask a factual question as to the basis of the study pointing to 97.1% peer reviwed abstracts. The opening excerpt quantifies the study in the following "...peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming'. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming..." - After doing the math - Including the small percent of those that do not support AGW) doesnt this mean that 97.1% of 4014 (or so) abstracts and not 97.1% of the science "community" or scientists agree ?? And if so, in the interest of truth and fact, dont you seek to clarify this within the media so they can more intelligently inform the public ?? - http://iopscience.iop.org/1748-9326/8/2/024024/pdf/1748-9326_8_2_024024.pdf
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heb0 at 00:17 AM on 4 June 2014Republican witness admits the expert consensus on human-caused global warming is real
"The science isn't settled" in much the same way that "the models are wrong." Just as models are by definition not completely accurate, scientific understanding of the climate is incomplete. But both of those statements, on their own, are useless, and both of them could be said about any field of scientific research, no matter how universally accepted. They require quantification to be anything meaningful. Yet, those who trumpet them don't seem interested in quantification, only in spreading that message.
I don't know much about Richard Tol, but lately he strikes me much like Roger Pielke: stubbornly contrarian yet slipperily vague. If memory serves me correctly, both have a strange habit of pedantically seizing on miniscule points of contention and then trying to use that to justify rejecting much larger parts of the science. When you call them on it, it's almost impossible to get them to admit which part of the conensus they disagree with, yet they will, if unchecked, make pretty denial-ish claims. It's fitting that they were both invited as witnesses.
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Alexandre at 22:45 PM on 3 June 2014Republican witness admits the expert consensus on human-caused global warming is real
I don't expect "skeptics" to build on previous conclusions or aknowledged evidence. It wouldn't surprise me if Tol claimed that "the science isn't settled" next month. Climate inactivity does not rely on coherence - quite the opposite.
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Tom Curtis at 20:01 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
scaddenp @257, based on ice core data, there is approximately a 90 ppmv rise in CO2 concentration between glacial and interglacial. That yields a CO2 increase per degree C between 11.25 and 30 ppmv per degree C with the former for an 8 C increase in temperature, and the later for an assume 3 C increase. A reasonable central estimate is 18 ppmv per degree C (5 degree increase). For the 0.8 C increase in temperature experienced since the industrial revolution, that yields and expected increase of 14.4 ppmv or 12% of the CO2 increase todate. As you say, it is unlikely that all of that increase would have happened over so short a time.
As an alternative emperical measure, taking the global temperatur anomaly from 1010 AD to 1800 AD (Mann 2008) and ice core CO2 records, the regression shows an 8.1 +/- 2.9 ppmv increase in CO2 per degree C. Based on that regression the expected increase for the global temperature increase since the pre-industrial of 0.8 C is 6.5 +/- 2.3 ppmv of CO2, or 3.5 - 7.3%. The time resolution of the CO2 record is 75 years, and I used a 75 year average of the temperature record to maintain equivalent resolution. That regression, therefore, yields a reasonable but not precise estimate of the increase that would have occurred from temperature increase alone.
As far as showing the absurdity of the pseudo-skeptic claims that the increase in atmospheric CO2 was caused by the temperature increase goes, the difference between 3% and 10% is not relevant. Therefore I indulged my habit of using conservative (for my position) estimates for rough figures where it makes little difference. The long and short, then, is that, yes I agree with you. But I don't think the difference is enough to warrant keeping track of for rough estimates.
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Dikran Marsupial at 18:54 PM on 3 June 2014Models are unreliable
Razo wrote "I can appreciate baseline study is a little more complex. I think the topic of my post 706 is not effected by this."
No, as KR pointed out, baselining is actually a pretty simple idea. It is a shame that you appear to be so resistant to the idea that you have misunderstood this and are trying so hard to avoid listening to the explanation of why the good fit is obtained during the baseline period (and why it is nothing to do with the models themselves). You will learn very little this was as most people don't have the patience to put up with that sort of behaviour. However, ClimateExplorer allows you to experiment with the baseline period to see what difference it makes to the ensemble. Here is an CMIP3 SRESA1B ensemble with baseline period from 1900-1930:
here is one with a baseline period of 1930-1960:
1960-1990:
1990-2020:
I'm sure you get the picture. Now the IPCC generally use a baseline period ending close to the present day, one of the problems with that is that it reduces the variance of the ensemble runs during the last 15 years, which makes the models appear less able to explain the hiatus than they actually are.
Now as to why the observations are currently in the tails of the distribution of model runs, well it could be that the models run too warm on average, or it could be that the models underestimate the variability due to unforced climate change, or a bit of both. We don't know at the current time, but there is a fair amount of work going on to find out (although you will only find skeptics willing to talk about the "too warm" explanation). The climate modellers I have discussed this with seem to think it is "a bit of both". Does it mean the models are not useful or skillful? No.
Razo also wrote "I wanted to point out to Dikran Marsupial, that the point of my post 706 was that the model that includes man made forcings only seems to be reducing the large error of the natural forcing only model in the 1850s when they are combined."
Well perhaps you should have just asked the question directly. I suspect the reasons for this are twofold: Firstly it is to a large extent the result of baselining (the baseline period for these models is 1880 to 1920), if you made the "error" of the "natural only" models smaller in the 1850s, that would make the difference in the baseline period bigger than currently shown and hence this is prevented by th ebaselining procedure. The same baselining causes the "anthropogenic model" to have large "errors" from the 1930s to the 1960s. The primary cause is baselining. Now if you have a better model that includes both natural and anthropogenic forcings, you get a model that doesn't have these gross errors anywhere, because the warming over the last century and a half has had both natural and anthropogenic components. So this is no surprise.
Now it is a shame that you didn't stop to find out what baselining is and why it is used when you first saw it on Tamino's blog, rather than carry on trying to criticise tghe models with incorrect arguments. Please take some time to do some learning, don't assume your background means you don't have to start at the beginning (as I had to), and dial the tone back a bit.
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scaddenp at 15:04 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
TC. I would have to humbly disagree with you on this one. I dont believe that we would have received a 10% increase - yet. Ocean mixing delays that solubility response.
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Tom Curtis at 14:50 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
rdbachel @254, you may be interested to read this summary of how we know the CO2 rise to be anthropogenic. The mass balance argument (we know how much we have emitted, and it is more than the increase in CO2) and the isotope arguments mentioned by scaddenp are the most important pieces of evidence, but no the only ones.
To slightly complicate things, had the temperature increase we experienced over the last century occurred without any increase in anthropogenic emissions over pre-industrial levels, we would still have experienced about 10% of the increase in CO2 levels that have actually occurred. This is known due to the known (from experiment) solubility of CO2 in water with temperature, and from comparisons to CO2 increases in past eras when temperatures have risen (as at the end of glacials). However, the rise in directly anthropogenic CO2 has been far faster than that potential increase. That is known from mass balance, and from the fact that ocean acidity increased over that period whereas it would have decreased if the CO2 increase in the atmosphere was due to thermal sources. Further, even if some of the increase should be attributed to temperature, that temperature increase is itself primarilly anthropogenic so that any CO2 increase in the atmosphere caused by it is also anthropogenic.
So called "skeptics" about AGW sometimes argue that the CO2 increase is natural and due to temperature rise. To do so they entirely ignore the rates at which CO2 rises in the atmosphere with increased global temperature (which are too small by a factor of 10 to account for the actual rise experienced), and the concurrent increase in ocean acidity, which proves the amount of CO2 dissolved in the ocean is increasing at the same time.
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scaddenp at 14:38 PM on 3 June 2014Nuclear testing is causing global warming
While they take a lot of energy, on the scale of other things, it is insignificant. World production of Uranium for all purposes has never exceeded 70,000 tonnes per year. World production of say coal by comparison is around 3,000,000,000 tonnes per year.
If you assumed that energy to extract uranium was say 10 times as much as that required to extract coal, (actually pretty similar), then energy cost from mining uranium is just 0.02% of that spent mining coal.
All the heat that we generate from all our industry in whatever form amounts to only 0.028W/m2. The heating from human-produced greenhouses gases is 2.9W/m2 by comparison. (See the "its waste heat" argument)
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scaddenp at 14:25 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
Firstly, we know with reasonable accuracy how much coal and petroleum are being burnt every year. We know that not all of that stays in the atmosphere (or the rise in CO2 would be larger). At the moment, the sea is moping up some of those emissions and becoming less alkaline in the process (that is also measured) so CO2 is not coming from the sea. The change in the pH allows us to calculate how much CO2 is being dissolved. As the oceans warm, this will change and eventually the oceans will begin to emit CO2 - hopefully not in the next century or so.
Sources of CO2 have different ratios of the carbon isotopes C14, C13, C12. For instance, fossil fuels have no C14 (it is short-lived). You can look at ratios of these isotopes in the air and water and check if the proportions match emissions from humans or some other source.
The "hole in the ozone layer" is a pictureque but inaccurate description. All the gases (including ozone) in the atmosphere are bound to the earth by gravity. The ozone layers doesnt trap any gas. Ozone is produced in tiny amounts in upper atmosphere by interaction of oxygen with UV radiation. This has a very important effect in shielding the lower atmosphere (where we live) from UV. Chemicals released into the atmosphere (CFC) are chemically destroying ozone especially above Antarctic so that it is much thinner ("the hole") in those places.
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rdbachel at 13:59 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
I was wondering if somebody could explain a part of the answer to me? Fistly, the answer states that rises have been noticed. If this is true, why is the complete rise solely based on humans and why can this not be a dramatic rise naturally occuring? What is to say that this is a new rise not previously seen in history before that is natural? I do, think that humans contribute to a rise in co2....to clarify. Secondly, I am assuming that the things I heard on tv were true and that there is a hole in the ozone. If there is a hole, why wouldnt the co2 just escape through that hole? Why wouldnt oxygen and nitrogen escape through that too?
Im really just trying to get some answers here. The problem, from my perspective and I think a good majority of others, is that as a lot of the comments show, this is science. I am not a scientist. That doesnt mean I was raised to trust anybody telling me what they have is true. I need this explained is some everyday, simple language please.
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rdbachel at 13:44 PM on 3 June 2014Nuclear testing is causing global warming
Hello everyone...well myself, right now. I think that the point of this argument was not that the nuclear weapons themselves have contributed to warming. I believe that the point of this argument is that the process of making the nuclear material requires massive amounts of fossil fuels to buid facilities, dig ore, refine, transport and then fire. Taking a conservative estimate of 2000 nuclear weapons fired since 1940 the amount of fossil fuel emissions would be a great number!
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michael sweet at 12:04 PM on 3 June 2014Models are unreliable
Razo,
Calibration of Global Climate Models is difficult. I understand that they are not calibrated to match the temperature trend (either for forcast or hindcast). The equations are adjusted so that measured values like cloud height and precipitation are close to climatological averages for times when they have measurements (hindcasts). The temperature trends are an emergent property, not a calibrated property. This also applies to ENSO. When the current equations are implemented ENSO emerges from the calculations, it is not a calibrated property.
Exact discussions of calibration seem excessive to me. In 1894, Arrhenius calculated from basic principles, using only a pencil, and estimated the Climate Sensitivity as 4.5C. This value was not calibrated or curve fitted at all— there was no data to fit to. The current range (from IPCC AR5) is 1.5-4.5C with a most likely value near 3 (IPCC does not state a most likely value). If the effect of aerosols is high the value could be 3.5-4, almost what Arrhenius calculated without knowing about aerosol effects. If it was really difficult to model climate, how could Arrhenius have been so accurate when the Stratosphere had not even been discovered yet? To support your claim that the models are not reliable you have to address Arrhenius' projection, made 120 years ago. If it is so hard to model climate, how did Arrhenius successfully do it? Examinations of other model predictions (click on the Lessons from Past Predictions box to get a long list) compared to what has actually occured show scientists have been generally accurate. You are arguing against success.
A brief examination of the sea level projections in the OP show that they are too low. The IPCC has had to raise it's projection for sea level rise the last two reports and will have to significantly increase it again in the near future. Arctic sea ice collapsed decades before projections and other effects (drought, heat waves) are worse than projected only a decade ago. Scientists did not even notice ocean acidification until the last 10 or 20 years. If your complaint is that the projections are too conservative you may be able to support that.
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scaddenp at 11:43 AM on 3 June 2014Models are unreliable
Razo: So? That doesnt make them unreliable nor unskillful. You seem to saying "its complex therefore they must be wrong". Much more importantly, you dont have to rely on models to verify AGW. Nor to see that we have problem. Empirically sensitivity, is most likely between 2 and 4.5. From bottom up reasoning, you need a large unknown feedback to get sensivitity below 2. (Planck's law get you 1.1, clausius-clapeyron gives you 2, with albedo to follow). And as for models, the robust predictions from models seem to be holding up pretty good. (eg see here ).
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John Hartz at 11:02 AM on 3 June 2014There's no empirical evidence
Razo: Here are some more facts about GCMs for you to ponder.
Climate Models Show Potential 21st Century Temperature, Precipitation Changes
Posted Sep. 27, 2013, NASA/GISS"New data visualizations from the NASA Center for Climate Simulation and NASA's Scientific Visualization Studio at Goddard Space Flight Center, Greenbelt, Md., show how climate models used in the new report from the United Nations' Intergovernmental Panel on Climate Change (IPCC) estimate possible temperature and precipitation pattern changes throughout the 21st century.
"For the IPCC's Physical Science Basis and Summary for Policymakers reports, scientists referenced an international climate modeling effort to study how the Earth might respond to four different scenarios of carbon dioxide and other greenhouse gas emissions throughout the 21st century. The Summary for Policymakers, the first official piece of the group's Fifth Assessment Report, was released Fri., Sept. 27.
"This modeling effort, called the Coupled Model Intercomparison Project Phase 5 (CMIP5), includes dozens of climate models from institutions around the world, including from NASA's Goddard Institute for Space Studies."
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Tom Curtis at 10:43 AM on 3 June 2014There's no empirical evidence
Razo @208:
1) von Storch et al (unpublished*) shows a temperature increase over the 15 year interval at 40% of what they claim to be the preceding 30 year trend in the only fully global temperature series used (GISS). They state:
"Estimates of the observed global warming for the recent 15-year period 1998-2012 vary between 0.0037 C/year (NCDC), 0.0041 C/year (HadCRUT4) and 0.008 C/year (GISS). These valuesare significantly lower than the average warming of 0.02 C/year observed in the previous thirty years1970-2000."
We immediately face problems in that 1970-2000 inclusive is a 31 year period so we do not know which trend they used. However, the Jan 1971 - Dec 2000 (Jan 1970- Dec 1999) trends are:
GISS: 0.166 +/- 0.058 (0.164 +/- 0.58) C/decade
NOAA: 0.167 +/- 0.054 (0.165 +/- 0.54) C/decade
HadCRUT4: 0.174 +/- 0.056 (0.168 +/-0.057) C/decade
Which ever trend you choose, von Storch et al have exagerated the preceding thirty year trends by 15-20%, thereby exagerating the extent of the slow down in temperature increase.
Further, they give incorrect values for the 15 year trends as well. The actual values are:
GISS: 0.073 +/- 0.147 C/decade
NOAA: 0.04 +/- 0.137 C/decade
HadCRUT4: 0.047 +/- 0.14 C/decade
Consequently the actual (reported by von Storch et al) ratio of trends using 1971-2000 for the 30 year trends are:
GISS: 0.44 (0.4)
NOAA: 0.24 (0.185)
HadCRUT4: 0.27 (0.205)
They therefore exagerate the slowdown by 10 or more percent.
2) von Storch et al avoid mentioning ENSO events to an extraordinary extent. There only reference is a casual mention that models have difficulty modelling ENSO events. He nowhere mentions the fact that 1998 was one of the largest El Nino events on record which, coming at the end of the thirty year trend and the start of the 15 year treand, exagerates the former while depressing the later. Nor does he mention the strong La Nina in 2008, nor the record La Nina (SOI Index) of 2011/2012. Nor does he mention the strong La Nina in 1974/75 (second strongest on record in the SOI). These La Ninas exagerate the 30 year trend, and supress the 15 year trend.
As a side note, von Storch et al's claims about the inability of models to model ENSO events are not strictly true. They were true of about half of models used in the CMIP3 intermodel comparison and the IPCC AR4; but it is not longer true of those used in CMIP5 and AR5. What models cannot do is generate ENSO events with the same timing as real ENSO events for the simple reason that that timing is essentially random.
3) von Storch et al make no allowance for the fact that 1998 was well above the temperature trend, or that 2011/12 by virtue of the La Nina were presumably well below it.
This is extraordinary. It means his entire argument is analogical to a person trying to prove that water does not settle to the same level because lines drawn from a point at the crest of a wave to other parts of the water surface have, on average, a negative slope.
Of course trends drawn from a peak well above the trend do not have the same statistical distribution as trends drawn from points on the long term trend line. For them to have the same statistical distributions, the series of data points (temperature records) must be a random walk. That the twentieth and early twentieth temperature record constitutes a random walk is a flat contradiction of the predictions of the models and climate scientists - yet that is the implicit assumption in von Storch et al's criticism. This flaw is made worse by both the fact that von Storch et al use a trend not only from a "peak", but to a "trough", and by the fact that they eschew any discussion of this issue.
IMO the statistical analysis in von Storch et al falls to the level of pseudo-science. I was greatly disappointed to see that von Storch had sunk that low.
* The article by von Storch et al was never published in any journal, but merely distributed on the internet. It follows, of course, that it is not peer reviewed.
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Razo at 10:01 AM on 3 June 2014Models are unreliable
michael sweet,
When I am talking about calibration, I look at it more like this (slightly simplified version follows):
Computer models are based on math. Math is equations. For curve fitting or trends one guesstimates an equation based on a graph. For more physical models, the equations are derived from basic principles. In both cases some 'calibration' is done to establish the equation's parameters. In the latter case, sometimes its easy like g=9.81 m/s2.
As I understand, GCMs basically integrate Navier Stokes equation. These are big and complicated. They can however be broken up into different pieces and a large part of the calibration can be done in parts. Some of the paramteres are omitted and some are estimated using yet another equation, and maybe curvefitting.
On top of this, computers don't do math like humans. They usually break it into small steps which they perform fast. So the solution process itself is approximate.
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Jim Hunt at 08:38 AM on 3 June 2014Republican witness admits the expert consensus on human-caused global warming is real
In my own article about the hearing I likened the proceedings to "a pantomime":
http://econnexus.org/the-scientific-consensus-on-climate-change/
I hope this doesn't sound overly political, but according to the IPCC AR5 WG I SPM “Warming of the climate system is unequivocal”. In the subsequent press release Lamar Smith said that:"A distinguished panel of experts involved in the IPCC and National Climate Assessment process unanimously stated that the science of climate change is “not settled,” as the President and others often state unequivocally."
I'm from the other side of the Atlantic, but it seems to me that an enterprising US lawyer could make a good case that Rep. Smith is guilty of libeling the President of the United States of America!
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MThompson at 08:36 AM on 3 June 20142014 SkS Weekly News Roundup #22B
In reference to knaugle on entry 11, you might take a look at the National Snow and Ice Data Center figure 6b. This shows that 2014 Antarctic sea ice is well above the two sigma variation of historic data. It would not be at all surprising that this trend contiues through winter (southern hemisphere). I'm making no attempt to identify the verbatum data source Mr. Bastardi referenced, but his assertion is likely true.
Having said that, you must be admonished that increasing Antactic sea ice in itself is scant evidence of global warming, one way or the other.
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Razo at 08:36 AM on 3 June 2014Models are unreliable
Hey KR. Thank you.
I wanted to point out to Dikran Marsupial, that the point of my post 706 was that the model that includes man made forcings only seems to be reducing the large error of the natural forcing only model in the 1850s when they are combined. this is about the figures 1 a, b, and c in the rebuttal on the intermediate page.
So KR I have a couple questions: 1) Is the common base the measured values or the ensemble mean? 2) does it make a difference to the results if you change the baseline dates?
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KR at 07:29 AM on 3 June 2014Models are unreliable
Razo - I would point out that the reference you made here to "Can climate models explain the recent stagnation in global warming" is to an un-reviewed blog article.
The published peer-reviewed literature on global models, on the other hand, states something quite different, such as in Schmidt et al 2014. This is discussed in some detail here on SkS. Climate model projections are run with forcing projections, and that includes the CMIP3 and CMIP5 model sets discussed by the IPCC. And each model run represents a response to those projected forcings.
When (as per that paper) you incorporate observed, not projected, forcings, it is clear that the models are quite quite good.
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KR at 07:13 AM on 3 June 2014Models are unreliable
Razo - Baselines are not complex in the least. Simply put, you take two series, and using a baseline period adjust them so that they have the same mean over that period -in order to see how they change relative to one another.
For example, comparing GISTEMP and HadCRUT4 without adjusting for the fact that they use different baselines:
And by setting them to a common baseline of 1980-1999:
A common baseline is really a requirement for comparing two data series.
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scaddenp at 07:09 AM on 3 June 2014Models are unreliable
Razo, climate modellers explicitly state that climate models have no skill at decadal level prediction. You seem to think from your experience as a numerical modeller, that they should be able to predict the trade winds (aka ENSO cycle), but then have tried predicting weather beyond 5 days? Weather prediction (and ENSO prediction) are initial values limited by chaos theory. Climate prediction is a boundary value problem where internal variability is bounded energy levels. (by analogy, you might get warm days in winter, but the average temperature for a month is going to be lower in winter than in summer). Climate models are trying to predict what will happen to 30 year averages. Got a better way of doing it?
They are incredibly useful tools in climate science, but if you are wanting to evaluate the AGW hypothesis, then please do it properly rather making uninformed stabs at things you havent understood. Perhaps the IPCC chapters on the subject where everything is referenced to the relevant published science as a starting point?
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Razo at 06:58 AM on 3 June 2014Models are unreliable
I wasn't think that calibrating means curve fitting or trend.
I know there are different opinions. Some, which are not deniers, appear to agree with me.
I can appreciate baseline study is a little more complex. I think the topic of my post 706 is not effected by this.
This is what I found for what a baseline climate is for. Amoungst other things, they do say its used for calibration.
http://www.cccsn.ec.gc.ca/?page=baseline
''Baseline climate information is important for:
-characterizing the prevailing conditions under which a particular exposure unit functions and to which it must adapt;
-describing average conditions, spatial and temporal variability and anomalous events, some of which can cause significant impacts;
-calibrating and testing impact models across the current range of variability;
-identifying possible ongoing trends or cycles; and
-specifying the reference situation with which to compare future changes.''
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Timothy Chase at 06:48 AM on 3 June 20142014 SkS Weekly News Roundup #22B
The moderator responded to 10:
[JH] Sicnetists typically use commonly accepted defintions of terms. "Climate change" and "Global warming" are no exceptions. The commonly accepted definitions of these two terms were developed by the IPCC and WMO. Those definitions are in the SkS Climate Science Glossary.
From the glossary:
... in its Article 1, defines climate change as: ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’. The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition, and climate variability attributable to natural causes. See also Climate variability; Detection and Attribution.
I would have assumed that "climate change" refers to a change in the "climate system that persists over an appropriate span of time". However, as such, I would not simply focus on the atmosphere or land or ocean surface, but the ocean at various depths, including temperature, circulation, salinity, and more broadly, chemistry. The chemistry would be particularly significant when it comes to the carbon cycle. And obviously, if you have a calcium carbonate shell, you might likewise be concerned with ocean acidity just as surely as you are with the temperature and salinity that also affect ocean circulation.
As I understand the nature of definitions, oftentimes there will be broader and narrower definitions that make use of different criteria and consequently have either different ranges or domains of applicability, where context might suitably determine what distinctions become significant, and thus context may determine which definition is in use, or alternatively, one may use a more specific term to indicate which definition is in use. "Climate sensitivity" is one such term, where one could be referring to either the Charney Climate Sensitivity that includes only the fast feedbacks (e.g., water vapor, clouds, sea ice and changes to the lapse rate) or the Earth System Sensitivity that includes both fast and slow feedbacks (e.g., ice sheets and the elements of the carbon cycle).
In my view, these are not different concepts but different yet closely related senses of the same concept. It becomes necessary to distinguish between them only once a distinction between fast and slow feedbacks is made.
Similarly, under local thermodynamic equilibrium conditions it may make sense to speak of only temperature, but under non-local thermodynamic equilibrium conditions one distinguishes between the kinetic temperature of matter and the Maxwell temperature of radiation since they are no longer strongly coupled. Moreover, under non-LTE conditions one may also distinguish between the temperatures of different quantum modes of molecular excitation due to the rate of collisions being insufficient to result in the equipartition of energy.
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MThompson at 06:33 AM on 3 June 20142014 SkS Weekly News Roundup #22A
Mr. Chase,
Thank you for your comment and research on the use of "sheeple" at other blogs.
I followed your suggestion to spend some time on the “WattsUpWithThat” website. As you reported, there were far more references to “sheeple” than on the present blog. While didn’t see the value of attempting a statistical analysis of the detailed usage of the term (it would be too subjective to be meaningful) , I did get quite a few chuckles from some of the other posts and comments. Perhaps higher web traffic would account for some of increased frequency of usage, but I see your point.
Perhaps I need to become a little more tolerant of this lack of civility so often encountered on the web. My hope is that the SKS blog will be more conducive to the open sharing of ideas, and the “regulars” will challenge those few bad actors to keep our discourse substantive. The television is quite sufficient for mindless entertainment.
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Dikran Marsupial at 06:28 AM on 3 June 2014Models are unreliable
Razo, none of the examples of the use of "calibration" you provide are referring to baselining, which kind of makes my point, you are not using the term in the ususal sense in climatology. There is a difference between baselining (which was the cause of the phenomenon you were describing) and calibration (a.k.a. tuning) in the sense of those three quotes. The models are not affected in anyway by baselining, it is a method used in the analysis of model output and is not part of the model in any way.
Please, do yourself a favour and try and learn a bit more before making assertions or criticisms (or at least pay attention to responses to your posts, such as mine at 711).
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Dikran Marsupial at 06:22 AM on 3 June 2014There's no empirical evidence
Razo can models be reasonably expected to predict the stagnation of temperatures over a 15 year period? The answer is essentially "no, but hey can be expected to predict that such stagnations will happen evey now and again (but not when)" and indeed they do, see Easterling and Wehner.
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michael sweet at 06:16 AM on 3 June 2014Models are unreliable
Razo,
In the second question at Real Climate's FAQ on Global Climate Models they say:
"Are climate models just a fit to the trend in the global temperature data? No. Much of the confusion concerning this point comes from a misunderstanding stemming from the point above. Model development actually does not use the trend data in tuning (see below). Instead, modellers work to improve the climatology of the model (the fit to the average conditions), and it’s intrinsic variability (such as the frequency and amplitude of tropical variability). The resulting model is pretty much used ‘as is’ in hindcast experiments for the 20th Century. - See more at: http://www.realclimate.org/index.php/archives/2008/11/faq-on-climate-models/#sthash.EiXtCir9.dpuf"
You say in reply to me: "If its just blind physics, it is improbable that the spread of the results would behave so differently in this time period." It appears to me that you are saying that the results are too good to be based on just the physics.
I am not an expert in this area, but it seems to me that you are confusing your definations of tuning and calibration for these models because you have not read the background material. This is very common and most of the experienced posters have seen this many times. As I understand Tamino's reference to baselining, they are aligning the data from 1980-2000 for comparison, they did not use that data to tune the models. Perhaps the alignment you referred to above is from how the data are graphed for comparison. Read the above Real Climate reference.
In your post at 712, your first and second references are to Regional Climate Models, not Global Climate models. They are not done the same way. You need to clear up in your mind what you want to discuss. Since you mentioned the "hiatus", it previously appeared that you were discussing Global Climate models.
Hans Von Storch is a respected scientist, but there are many different opinions on how well Global Climate Models are performing. Tamino states at the end of the post you linked above "The outstanding agreement holds not just for the 20th century, but into the 21st as well — putting the lie to claims that recent observations somehow “falsify” IPCC model results." (my emphasis) That was in 2010, but Tamino still feels that climate models are holding their own.
There are several posters here that are more experienced that I am. They seem to be holding back. Perhaps if you make less statements about the Physics being too good people will be more friendly.
You frequently make sweeping statements and confuse apples and oranges. For example, your confusion of Regional and Global climate models above. This makes you appear hostile. Dikran Marsupial is very knowledgable and can answer your questions if you pose them in a less hostile tone.
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knaugle at 05:30 AM on 3 June 20142014 SkS Weekly News Roundup #22B
I noticed on the wattsupwiththat.com blog that Meteorologist Joe Bastardi (on 5-23-2014) claims that NOAA predicts above average sea ice extent for August. Yet I cannot find this directly, except for cryptic links to plotted data, and NSIDC seems to be showing below average trends. Given the skeptical/denier nature of WUWT I am not surprised, but was curious if anyone knows more about where JB got his data?
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Razo at 05:13 AM on 3 June 2014There's no empirical evidence
I have posted this link elsewhere, but I post it here to show that others share my critism of climate modeling not predicting recent stagnation in global warming. Also he considers the stagnation to be a 15 year period from 1998 to 1012.
http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming
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Razo at 04:50 AM on 3 June 2014Models are unreliable
Well here are a few examples of the use of the word 'calibration' or synonyms in climate change literature, found by simply googling 'calibration climate change model'. I think my use of the term and the idea are reasonbly inline with the scientific community. Where am I going wrong on this? I have not read each of these exhustively. I am only showing showing the use of the expression.
1)http://www.iac.ethz.ch/groups/schaer/research/reg_modeling_and_scenarios/clim_model_calibration
This is a Swiss institute for atmospheric and climate science:
''The tuning of climate models in order to match observed climatologies is a common but often concealed technique. Even in physically based global and regional climate models, some degree of model tuning is usually necessary as model parameters are often poorly confined. This project tries to develop a methodological framework allowing for an objective model tuning with a limited number of (expensive) climate model integrations.''
2)
http://journals.ametsoc.org/doi/abs/10.1175/2011BAMS3110.1
American meteriological society
''Calibration Strategies: A Source of Additional Uncertainty in Climate Change Projections''
3)http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming
An article titled ''Can climate models explain the recent stagnation in global warming?''
''In principle, climatemodel sensitivities are calibrated by fitting the climate response to the known seasonal and latitudinalvariations in solar forcing, as well as by the observed climate change to increased anthropogenicforcing over a longer period, mostly during the 20th century. It would be difficult to modify the modelcalibration significantly to reproduce the recent global warming slow down while still satisfying theseother major constraints.''
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villabolo at 04:08 AM on 3 June 20142014 SkS Weekly Digest #22
@2 Magma,
Good question.
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Dikran Marsupial at 03:17 AM on 3 June 2014Models are unreliable
BTW Razo, baselining and calibration are not the same thing. Yes, the variability in the baselining period should be expected to underestimate the true variability of the model projections, even if the model physics is 100% correct.
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Dikran Marsupial at 03:11 AM on 3 June 2014Models are unreliable
Razo writes "When I make a mistake, people expect me to have a PHD in GCM. "
and yet on another thread, (s)he writes " I am not in the climate field, but I do have experience with numerical modelling. I simply think GCM should be able to predict trade winds and ocean warming."
where (s)he is explicitly claiming to have a background that provides a position to criticise GCMs. As it happens the criticism shows a fundamental lack of understanding of what GCMs are designed to do and what can be expected of them. Razo, you need to understand first and then criticise. Asking questions is a better way of learning than making assertions or criticism, especially when you are not very familiar with the problems. Your tone is not "reasonably passive" as the quote above demonstrates.
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Magma at 03:00 AM on 3 June 20142014 SkS Weekly Digest #22
Why is a Catholic or Anglican bishop included in the cartoon, considering that both those churches publicly recognize the reality and the seriousness of AGW?
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mperkel at 02:56 AM on 3 June 2014Venus doesn't have a runaway greenhouse effect
I'm not convinced of Venus having a runaway greenhouse effect. With 92X atmosphere than Earth - and if Venus has a radioactive heat source like Earth that the insolation effect, as well as some solor heat trapped in the atmosphere - would be keeping the planet from cooling off.
Additionally - I object to comparing Venus to Earth in this regard because the fact is that you can't compare a planet with 92X atmosphere and being closer to the Sun and having different atmospheric chemestry as being similar.
And - since almost no light makes it to the surface of Venus all solar energy is absorbed in the atmosphere. Therefore if a solar heating event is happening then the atmosphere would have to be hotter than the surface and heating the whole planet by convection and conduction. But the atmosphere is not hotter than the surface so that tends to disprove the runaway greenhouse idea.
The simplier and more plausable explanation is that like Earthg Venus was molten and because of 92X atmosphere it never cooled off, as opposed to the idea that it used to be cool and was heated up.
I'm not buying it.
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Timothy Chase at 02:43 AM on 3 June 20142014 SkS Weekly News Roundup #22A
MThompson wrote:
I for one find it abhorrent that posters to this blog refer to a group of humans as "sheeple." I infer from this that the writers use the term to indicate disdain for the relatively uneducated and impoverished peoples of the earth.
I performed two searches. One was for sheeple in Skeptical Science, the other for sheeple in WattsUpWithThat, both using Google.
site:skepticalscience.com sheeple returned 9 webpages
site:wattsupwiththat.com sheeple returned 501 webpages
Now before you think I am responding with a "they do it too" or "they do it more often" I should also let you know that I looked at the 9 instances at Skeptical Science.
There was the reference to the cartoon the response to the reference to the cartoon, neither of which was in a context specific to the acceptance or dismissal of climate science, one reference to the "uneducated masses" who don't get climate science. In this case the comment was posted by someone calling himself "actually thoughtful" who isn't a regular, just passing through. The 6 other webpages contained references by those who are pro-science refering to those who are pro-science — mocking the use of the term itself.
I will let you discover for yourself how the term gets used at Watts Up With That.
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Timothy Chase at 01:45 AM on 3 June 20142014 SkS Weekly News Roundup #22B
MThompson wrote:
Now, based on the theme of Ms. Flam's missive, I wonder how the IPCC in 1988 settled on the name of their august panel. Was there a consensus some 25 years ago that rejected IPGW as the moniker of the most important international body for the future of earth? I'm sure that within the vast experience range of SKS commenters someone can provide interesting history about this divisive nomenclature.
Personally, I have thought that "climate change" is better because it is the wider term, which is also probably part of the reason why they chose it. In my view, the more important issues won't be heat waves but droughts and flooding. Climate change is also wide enough to encompass ocean acidification, which has the same root cause and, like droughts, will greatly impact our ability to feed our people. In fact, if we could do this over again, I would prefer the term "industrial climate disruption" as "industrial" is suggestive of both the cause and scale and "disruption" alludes to the how we are leaving the relatively stable Holocene Epoch, during which agriculture was developed and civilization flourished, for something that appears a great deal less stable.
However, "global warming" appears to be the term that the public find it easier to grasp, perhaps because it is less abstract, something that they can more easily relate to the perceptual level. It is a bit like communicating abstract ideas through metaphor, I suppose. And it is probably best to stick to one phrase or the other. Otherwise one is likely to confuse.
Moderator Response:[JH] Sicnetists typically use commonly accepted defintions of terms. "Climate change" and "Global warming" are no exceptions. The commonly accepted definitiobns of these two terms were developed by the IPCC and WMO. Those definitions are in the SkS Climate Science Glossary.
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Razo at 01:43 AM on 3 June 2014Models are unreliable
Micheal Sweet, I think my tone is reasonably passive to suggest I'm open to correction. I am not a denier, I present myself as an educated skeptic, and I am here to learn. When I make a mistake, people expect me to have a PHD in GCM. I think the point of calibration can be a little subtle, but it doesn't take away from my post.
I did read about AR4 models:
http://web.archive.org/web/20100322194954/http://tamino.wordpress.com/2010/01/13/models-2/
Here they say
''But there’s a sizeable spread in the model outputs as well (especially in the early 20th century, since these results are set to a 1980-2000 baseline).''
In this case the spread is very little in the 1980-2000 period. If its just blind physics, it is improbable that the spread of the results would behave so differently in this time period.
Also in the rebuttal above, the basic section, they say models use hindcasting. So if they test with hindcasting, and it doesn't work, one tries to improve thier model. So this is what I call calibrating. Am I wrong on this?
I think I see the word 'calibrate' has a charged meaning, becasue deniers use it. Well I didn't know that. LOL. Anyway, I presented my definition of calibrate. Please note the above question mark indicating a question--you invited me to ask.
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michael sweet at 00:40 AM on 3 June 2014Models are unreliable
Razo,
You say "The model aslso shows a great match around the 80s and 90s, which is probably what it is calebrated to." This is fundamentaly not how climate models work. You are coming in from another line of work and incorrectly applying your modeling methods to climate. The climate models are designed from the ground up using basic physics principls and are not "calibrated" to any period. If you wish to continue posting on an informed board you need to do your homework and stop making baseless assertions.
You would be much better served by asking questions about how climate models work, which you obviously do not understand, than incorrectly complaining that those models do not work properly. Real Climate has several basic links on how climate models work.
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chriskoz at 00:01 AM on 3 June 2014Global warming and the vulnerability of Greenland's ice sheet
wili@6,
I checked AR5 Table 4.6 and found out that my previous IPCC numbers were the last 18y average IS loss trends. Because IS melt is accelerating, the more recent trends - last 6y - are higher:
Period Ice sheet loss (mm yr–1 SLE)
Greenland
2005–2010 (6-year) (0.63 ±0.17)
1993–2010 (18-year) (0.33 ±0.08)
Antarctica
2005–2010 (6-year) (0.41 ±0.20)
1993–2010 (18-year) (0.27 ±0.11)
Combined
2005–2010 (6-year) (1.04 ±0.37)
1993–2010 (18-year) (0.60 ±0.18)So, AR5 latest 6-year trend is consistent with (McMillan 2014), no surprise here. The AR5 combined 1.04mm/y value constitutes about 1/3 of current total SLRR of 3.2mm/y.
But the question when we are going to see IS contribution emerging as dominant factor is still too hard to tell. You can check AR5 chapter 4 summary e.g. in Bamber presentation: Look esp. at Figure 4.25 on page 12 and try to extrapolate... Or, with Hansen's fastest doubling every 7y, you'll arrive at 8mm/y by early 2030s... But with more realistic IMO doubling every 10y+, you'll arrive at 2mm/y by 2020s which still less than other contributions, and 4mm/y (a dominant contribution) by 2030s.
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Composer99 at 23:44 PM on 2 June 20142014 SkS Weekly Digest #22
Regarding the Skeptical Science Highlights:
Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows. by Howard Lee received the most comments of the articles posted on SkS during the past week once again reflecting how many people are interested in geolgical extinction events.
One thing that struck me about the comment thread of this post has been the overall high quality of the comments. It's not the case that someone started spouting re-hashed rhetoric which others have been forced to step in and debunk - instead the commenters have been sharing perspectives and papers.
It's the kind of comment thread that I suspect every science blog aspires to have all the time.
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Composer99 at 23:07 PM on 2 June 20142014 SkS Weekly News Roundup #22A
MThompson:
I don't think it's going out on a limb to say that, when someone links to an XKCD comic mocking the "wake up, sheeple!" thing (*), it's not serious.
I might add that the impression I have from posts here at Skeptical Science which (a) detail the authors' direct experiences with working in developing countries around the world, or (b) share links to news agencies and various organizations, that the majority of people living in developing countries are generally quite aware of how AGW is affecting their day-to-day lives - at least, more aware than too many in affluent countries who allow themselves to be blinded.
(*) Does anyone actually use the term sheeple in a non-ironic way anymore?
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Leland Palmer at 22:35 PM on 2 June 2014Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.
On the other hand, the high salt methane hydrates could be quite significant and could be a major piece of the puzzle of how these past mass extinction events occurred. The high salt hydrates could also be crucial to predicting how our manmade extinction event will proceed, and what the eventual outcome will be.
From an earlier thread on Skeptical Science:
Such high salt methane deposits may be fairly common, according to authors including Maria Torres and Miriam Kastner:
OCCURRENCE OF HIGH SALINITY FLUIDS ASSOCIATED WITH MASSIVE NEAR-SEAFLOOR GAS HYDRATE DEPOSITS
CONCLUSIONS
Massive gas hydrate and chloride brines in near- seafloor sediments along continental margins are not at all uncommon, and may represent a significant carbon reservoir, which is susceptible to oceanographic perturbations....Preliminary estimates suggest that there is approximately 125 x 10-3 Gt of carbon trapped in the Ulleung Basin brine patches. If we assume that there are 200-500 such locations sites worldwide, this will represent a ~25 to 62.5 Gt carbon, which is 0.25 to 12% of the total carbon thought to be sequestered in gas hydrate deposits globally.
The existence of these deposits may be the answer to the disconnect between the geological evidence of past methane catastrophes and our current lack of understanding of how these mass extinction events occurred.
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MThompson at 22:24 PM on 2 June 20142014 SkS Weekly News Roundup #22A
I for one find it abhorrent that posters to this blog refer to a group of humans as "sheeple." I infer from this that the writers use the term to indicate disdain for the relatively uneducated and impoverished peoples of the earth. Most people have no way to understand how the issues of the carbon cycle affect them. They are fighting day-to-day for food and energy to survive. All this while the erudite sit in air conditioned abodes on high munching carrots from vertical gardens perched on balconies with panoramic views. But I suppose that many readers of this generally insightful blog will relish the humor of such posts.
If my inference was too hastily drawn, then please accept my heart-felt apology, and keep up the good work! -
Dikran Marsupial at 20:19 PM on 2 June 2014There's no empirical evidence
Razo wrote "I also do criticize global models for not capturing decade long cooling intervals very well"
Criticising models for not being good at something they are not designed to do and for which they do not claim a high degree of skill suggests that you have not put much effort into finding out what models do and how they work. I criticise them for not being able to predict volcanic eruptions. This is about as meaningful a criticism as Razo's ;o)
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Razo at 19:28 PM on 2 June 2014There's no empirical evidence
scaddenp, I must confess to not reading it thouroghly enough. I seem to remember it differently, or was relying on journalists interpretations too much. For that I apologize. But nevertheless Fig 1 does describe cooling over part of the last decade
"Observations of global average surface air temperature (SAT)
show an unequivocal warming over the twentieth century1,
however the overall trend has been interrupted by periods
of weak warming or even cooling (Fig. 1)."I also do criticize global models for not capturing decade long cooling intervals very well, and not predicting trade winds. I am not in the climate field, but I do have experience with numerical modelling. I simply think GCM should be able to predict trade winds and ocean warming.
Moderator Response:[JH] Your "experience with numerical modeling" is nor a substitute for doing your homeowork on GCMs before proceeding to critique them. Please stop flying blind and look before you leap.
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Glenn Tamblyn at 18:26 PM on 2 June 20142014 SkS Weekly News Roundup #22A
Non-Scientist.
No, not yet. The Sheeple may be fractious and disturbed, filled with an ill-defined disquiet. But not awoken, not yet.
It would take a ..... WHAT IS THAT SMELL?......
.... A Stinking mix of dung and lanolin.....
.... Those SCREAMS.... Just like the sound of Shearers dying.....
Nobody panic.... JUST NOBODY PANIC.....It's just a few sheep!
Oh My God!!! Billions of Sheep. And they aren't smiling!
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