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KR at 02:41 AM on 1 June 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Some observations:
- It's entirely reasonable to find a few individual abstracts that folks can disagree upon (despite the 2 or 2/3 raters who agreed on classifications in Cook et al). But that means nothing without context, with statistics on how many disagreements barry or anyone else finds. Statistics, or it's meaningless nit-picking.
- The context of AGW should be understood by anyone submitting peer-reviewed papers on the subject, as per the IPCC reports, as "Greenhouse gas forcing has very likely [>90% probability] caused most of the observed global warming over the last 50 years." Arguments otherwise really only make sense to people who are not familar with the field - and are hence irrelevant to the paper under discussion.
At this point, the circling of the arguments re: consensus, and the wash/rinse/repeat cycle of arguing over individual abstracts absent the context of statistics on how many are inarguable, strikes me as excessive repetition as per the Comments Policy.
Perhaps folks could reserve further comments to aspects of this topic not already reviewed ad nauseum?
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dana1981 at 01:12 AM on 1 June 2013Global warming is here to stay, whichever way you look at it
John Cook covered the Lu argument in 2010. This is the third or fourth iteration of the same fundamentally flawed argument, without acknowledging that other scientists have revealed those fundamental flaws. It's BS (bad science).
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dhogaza at 00:58 AM on 1 June 2013Global warming is here to stay, whichever way you look at it
There's a silver lining in the Lu fiasco ...
"He claims to have good statistical evidence that both ozone depletion and global warming come almost exclusively from halogenated compounds"
Once upon a time, this lead one Tony Willard Watts to post, with a big splash, that Lu has shown that halogenated compounds, not CFCs, were responsible for ozone depletion, thus the Montreal accords were based on incorrect science, as CFCs have no affect on ozone.
Think about that for a moment ...
Hilarity ensued ...
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shoyemore at 00:18 AM on 1 June 2013Global warming is here to stay, whichever way you look at it
tcflood #29, it's
I was on a discussion about this (is Lu saying that CFCs lifted earth out of the Ice Ages?) when a "JohnMashey" interjected with the following information:
Lu has been on this kick for years, publishing in increasingly less credible journals and ignoring all refutations. See Gavin Schmidt on Lu:
search RealClimate for 2011 post: from ‘interesting but incorrect’ to just wrongwww.realclimate.org/index.php/archives/2011/07/lu-from-interesting-but-incorrect-to-just-wrong/
Note that Int J. of Modern Physics B (NOT a climate science journal) did not help its reputation by publishing the absurd Gerlich & Tseuschner paper, also analyzed at RC.
True to form, the paper has done the rounds of the usual blogs and the Wall Street Journal.
So, while the fake-skeptics may twitch with fake-excitement, let's not hold our breath that this is the ex-machina solution we have all been waiting for.
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tcflood at 23:51 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
Have you guys seen this paper by Q.-B. Lu at the U of Waterloo?
http://arxiv.org/ftp/arxiv/papers/1210/1210.6844.pdf
He claims to have good statistical evidence that both ozone depletion and global warming come almost exclusively from halogenated compounds.I got it off Curry's site, so even if it is 100% bogus, I suppose we will be hearing about it from now on.
I'd really like to hear what you think.
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noelfuller at 22:01 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
LarryM (18) and Composer99 (13)
Thanks for the references, I have seen them before and the one somewhere with all the circles, and found them very helpful. However, they apportion heat content rather than indicate total heat content as a line in kilojoules
which is what I am looking for. I would expect the line to be free of internal acean variability, but wobbling a bit with aerosol, cloud and solar variation but overcoming the ocean lag effect relative to surface atmospheric temperatures. Greenhouse gas buildup would be the dominant influence on the curve. However, I suspect that this is rather hard to achieve with precision.
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noelfuller at 21:46 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
owenamoe 7
I think we have to have a reference to where the temperature of some part of the atmosphere is measured and because that is generally where we can easily reach to place a thermometer in a stable position we are measuring temperature within a few metres of the soil or sea surface. I understand that we have to get up a wee bit when we want to get air temperature over ice. If we left out the reference to surface we would be in the rather silly position of implying the measured temperature was the average temperature of the entire troposphere say. We know the air gets colder as we gain altitude. By surface atmospheric temperature we are of course not talking about soil temperatures or sea surface temperatures. This measure is in some ways analogous to sea ice extent. Both measures exist because we can measure them with what we have. Sea ice extent is also subject to which way the wind blows, and I suspect to how thin the ice is. By far the best measure is sea ice volume but that is much harder. Similarly surface atmospheric temperature is also a representative measure. the easiest to record with the longest instrumental history, interestingly influenced by all the agencies that shove heat about in the ocean but by far the most telling figure if only we could measure it as readily is heat content.
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Dikran Marsupial at 19:09 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry Did the simulations performed for the paper include the last 200 years, and did they include the rise in atmospheric CO2 over this period due to anthropogenic emissions?
(Hint: I rather doubt they simulated the whole of the last 180 million years as this would have taken rather a lot of time to run on the computer).
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JasonB at 18:54 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
You might be better off using a category other than Paleoclimate for your checking.
Firstly, due to the fact that it deals with the ancient past, it has almost the equal-lowest "relevance" rating of the four categories (only 22% of papers were classified as expressing an opinion on the topic, vs nearly 57% of Mitigation papers and 32% of Methods papers) and is more likely to include factors that are going to make it difficult to categorise without a deep understanding of the topic.
Secondly, it is also the smallest category (6.6% of all papers), and so even if you somehow prove that every one of the papers classified in favour of the consensus should have been neutral instead, it will have almost no impact on the final result. (If you want to show a problem in general, and not just with Paleoclimate papers, then I would argue you should randomly select from all papers and not just a particular category.)
If you are going to pick a particular category, I'd suggest Mitigation: it has the highest Consensus rating (99.84% — 1,912 rated in favour, just 3 rated against; 20 × level 1 vs 0 × level 7, 418 × level 2 vs 2 × level 6, and 1,474 × level 3 vs 1 × level 5) as well as the highest percentage of papers rated as being relevant (nearly 57%).
Regarding the four papers we both checked, Cook et al rated two as endorsing the consensus and two as neutral, and you rated two as endorsing and two as neutral. Even though you agreed with Cook et al on two and disagreed on two, the net effect was the same because the two you disagreed on went opposite directions. Of course, this sample is far too small to draw any conclusions, so you might want to use the tool to try a much larger set of papers and compare your ratings with Cook et al, but the point is this: when the numbers are so highly skewed in one direction, even gross errors have very little impact on the final results, and so far there's no indication of gross errors. As Tom originally pointed out, even if half of the original authors mis-classified their papers as endorsing the consensus instead of being neutral, the results would still be overwhelming.
As for finding full papers that should be classified differently to what you would get based on the abstract alone, in and of itself this isn't a problem — it's only a problem if abstract classification is not an unbiased estimator of paper classification. In other words, if papers endorsing the consensus are more likely to say something to that effect in their abstract than papers rejecting the consensus (or vice-versa). The fact that such a large number of papers that Cook et al classified as neutral were rated by their authors as taking a position on the topic can be a simple reflection of the additional information in the paper (or the fact that they don't have to try to figure out what they mean) rather than any indication that the authors used a lower "bar" than Cook et al.
If you are going to keep checking papers, don't forget to report how many you checked that you didn't have a problem with the rating of. If you pre-filter the information to only report those that you disagree with, then we have no way of knowing what the impact of that is. Disagreeing with 100 out of 100 papers is very different to disagreeing with 100 out of 10,000.
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Lanfear at 16:56 PM on 31 May 2013The 5 characteristics of global warming consensus denial
"Again; if you feel this is in error, do the work. Evaluate some abtracts with your particular critera, present your data, and see if it holds up"
This indeed is why we can with confidence talk about denialists: The lack of relevant (scientific) evidence backing up their claims which contradicts the well known science.
We have a excellent example: The claimed falsification done at CRU. Why is it that not a single denialist has taken any time to actually prove their claims (thus also proving that the label denialist is false)?
The only case where the result was actually displayed AFAIK, was the BEST reconstruction, and that did not go the way the (then) sceptic crowd assumed, resulting instead to outright rejection (again without any tangible material to back them up), as well as a slew of argument fallacies such as 'true scotsman' and not to forget in one particular case, a total backtracking of earlier claim (you know who this was).
The reality is, that as long as they choose to remain as bystanders spouting their anti-scientific belief-artifacts at the scientific arena, not participating using the scientific methods (ie. 'doing the work' as KR and many others in this thread expresses it), they will, by their own actions, remain denialists.
Maybe the most comical part is that by voicing their poorly founded thoughts, the deniers are actually providing valid material for an objective analysis of the denial, as attested by the Lewandowsky et al. studies.
Another absurdity is that the denialists continuously claim that the climate science has been politisized, yet their main method of critique is that found in politics (by innuendo, character assassination etc), not science.
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Tom Curtis at 15:59 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Barry @242:
"We have conducted four Early Jurassic experiments with increased CO2, using the explicit method; however, specifying SSTs minimizes the climate effects by previously accounting for many CO2-induced feedbacks (sea-ice decrease, water-vapour increase), thus limiting the CO2 effect to direct radiative heating."
(My emphasis)
How is that not clear enough for you?
I have already summarized this quote, including a quote of the final crucial phrase and directed you to the part of the article which contains it; and yet now you want to put your hazy understanding against the author's direct statement.
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Tom Curtis at 15:49 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry, this is the continental configuration during the Jurassic:
This is the continental configuration now:
The paper and abstract asserts that the change in ocean currents brought about by that difference in continental configuration between the modern and jurassic may be enough to account for a 5-10 degrees C difference in GMST. Do you wish to suggest that that is significant (or even relevant) evidence suggesting that the motion of Africa 2.15 meters to the North East over the last century has caused a significant portion of the 0.7 C warming over the last 100 years? If you do not, then the effect of the very large difference in continental positions between the modern and the Jurassic is irrelevant to warming over the last century, and therefore irrelevant to the classification of the paper (and abstract).
I have chosen the case of Africa as it currently has the largest current impact on GMST by my understanding. You may prefer to use the (at most) 10 meter increase in the width of the Atlantic over the same interval, and argue that that has significantly increased GMST. In fact, pick any continental motion, or sum of them and tell me you think there is evidence that their combined effect has caused 0.2 C warming over the last century (ie, sufficient to be statistically distinguishable) and show me a remotely plausible theory as to how it could do so, and I will accept that the paper should have been rated a six or seven.
Absent that, you are merely focussing on an irrelevancy in assessing the paper, and IMO a transparent irrelevancy.
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nealjking at 15:02 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
I believe your interpretation of the first sentence of the abstract is absurd and perverse: It's pretty clear that they're NOT including the last 200 years within the period of study, which comprises 180 million years. For one thing, they contrast the warming of the period under study from that of "the present": You can't do that unless they're mutually exclusive. A minimization of the role of CO2 during the Jurassic has precisely nothing to imply about the role of CO2 today; especially since CO2 did not jump from 280 ppm to 400 ppm within 200 years during the Jurassic, as it has in the present era.
Further,
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Rob Honeycutt at 14:27 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
@19... "(-snippedy-snip-snip-)"
I do believe you enjoyed that, DB.
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dhogaza at 14:15 PM on 31 May 2013The 5 characteristics of global warming consensus denial
Take solace in the fact that about 90% of climate science denialism rests on stolen e-mail from CRU and from Skeptical Science.
If it weren't for felonious conduct, what would they have?
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DSL at 14:11 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
Of course! Cottonballs returns!
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DSL at 14:10 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
Yah, but it seems like I saw something almost identical to this over at SoD a year ago or so. About eight comments of interchange between the regulars and this person, and off s/he went in a huff. I guess we'll see if CSR is a drive by.
Suddenly, all the pyrgeometers in the world stop working. Puckrin and Evans are taken out in handcuffs. Watts posts that he knew it all the time . . . he was working on a paper, in fact. It was going to be a blockbuster . . . -
scaddenp at 14:04 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
Well with so many other sites banning him, he must be getting desparate - just not desparate enough to read a physics textbook.
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William Haas at 13:41 PM on 31 May 2013Uncertainty no excuse for procrastinating on climate change
dkaroly, Thanks for the new graph. It does a lot to help sell the validity of your simulations.
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Tom Curtis at 13:27 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
DSL, classic Sky Dragon of course. Invents a greenhouse theory they know to be false, and kill it - then assert without warrant that the theory they have shown to be false is the actual theory used by climate scientists.
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Tom Curtis at 13:25 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
An evident lack of Climate_Science_Research @19 claims that:
"If you believe that planetary surface temperatures are all to do with radiative forcing rather than non-radiative heat transfers, then you are implicitly agreeing with IPCC authors (and Dr Roy Spencer) that a column of air in the troposphere would have been isothermal but for the assumed greenhouse effect."
In fact the IPCC states any thing so silly as to claim that a column of air in the troposphere would be isothermal were it not for the greenhouse effect. Nor, to my knowledge, does any scientist associated with the IPCC scientist nor Spencer. Certainly no climate physicist would be so silly. Rather, they state the opposite, ie, that without a non-isothermal troposphere there would be no greenhouse effect.
The greenhouse effect does influence the lapse rate in the troposphere, but only in a small way. It would cause it to be much larger (ie, much greater reduction of temperature with altitude) except for convection. If the slope exceeds a certain value, that generates convection which brings it down to that value (the dry adiabatic lapse rate). If the air is moist, the release of latent energy of vaporization as the water vapour condenses further reduces the lapse rate. These factors, then, shift the lapse rate from what it would be in their absence; but the troposphere would cool with altitude even in their absence.
Having given a wrong account of the history and state of knowledge of planetary physics, he says,
"The gravitationally induced temperature gradient in every planetary troposphere is fully sufficient to explain all planetary surface temperatures."
But that is absurd. It is equivalent to saying that knowing the slope of one line is sufficient for knowing its intersect with the x-axis.
The lapse rate is indeed a gradient (slope) and would exist without a green house effect. But for any slope there are an infinite number of possible intersects with the x-axis. Only once you specify the co-ordinates of at least one point on the line does the slope tell you the intercept. Thus when the x-axis is temperature and the y-axis is altitude, the lapse rate is represented by any line having the same slope on the graph. But only when we find the temperature at a given point on such a line do we determine the intercept with the x-axis (surface temperature). And, of course, the temperature that determines the surface temperature is governed by radiative physics.
I recommend that the ill named Climate_Science_Research actually read the last link, and take up the subject there (where it is on topic) rather than here (where it is not).
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DSL at 13:09 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
Hrmmm . . . appears to b a copy/paste and sounds awfully familiar. Where have I heard this before . . .
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barry1487 at 12:57 PM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
This paleo abstract (1992), assigning no value to anthro greenhouse warming, or even mentioning anthropogenic influence, was rated 3.
No mention of anthro influence or value in the body of the paper either, but at one point it is remarked that the effect of enhanced greenhouse gases in the Early Eocene may have been 'minor'. No idea how a self-rating Author would rate this one.
This 1993 abstract assigns no value to CO2 warming, saying only that post-industrial increases in CO2, CH4 and N2O "may well have contributed to the observed global warming." Marked as 3 (no full version).
.....
I've been skimming titles in paleoclimate, ignoring ones that do not immediately present themselves as pertaining to the modern period. But I've noted that Cook et al have rated at level 3 any paper which suggests enhanced CO2 levels should cause global warming. Most times, the abstracts I've looked at make no mention of antrho influence or the modern period, and give no quantification on CO2 contribution to warming.
Contrary to my thesis upthread, it appears that Cook et al may have rated at the lower bar (any amount of warming from enhanced CO2). If so, this would make the comparative results Cook13/self-rating Authors less problematic.
Tom, it appears you may have overestimated the ratings stringency of Cook et al. Scroll through the paleoclimate category and I believe you will concur.
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Climate_Science_Research at 12:40 PM on 31 May 2013Global warming is here to stay, whichever way you look at it
(-snippedy-snip-snip-)
Moderator Response:[DB] More Doug Cotton sock puppetry. Privileges revoked, again.
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barry1487 at 11:56 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I wonder, Tom, what you make of Dana Nuticelli's comment;
"Note that if a paper said humans are causing less than 50% of global warming, or that another factor was causing more than 50% (or ‘most’, or some similar language), we put it in our rejections/minimization of the human influence category. Our basis was the IPCC statement that humans have caused most global warming since the mid-20th century. But if a paper simply said ‘human greenhouse gas emissions are causing global warming’, that went into the endorsement category as well. After all, there’s no reason for most climate research to say ‘humans are causing >50% of global warming’ (except attribution research), especially in the abstract."
http://ourchangingclimate.wordpress.com/2013/05/17/consensus-behind-the-numbers/#comment-18747
That looks to me like a qualitative statement rated as a qunatitative one.
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barry1487 at 11:53 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Tom,
your points are well-taken. For your point 3), however, I believe they ran simulations to test for CO2-specific warming, and the feedbacks were not pre-imposed. Read the bottom of page 557, 1st column ("Table 3...", where they go on to state that feedbacks to CO2 forcing are the primary cause of warmth.
In the conclusions, they mention that their results have implications for "future" warming.
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barry1487 at 11:28 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Dikran,
For me, the abstract "minimises" the role of CO2. I do not know how it can be read any other way, unless one were to completely ignore the first sentence. In fact, the first sentence strongly suggests a 7 rating might be appropriate. (Leaving aside, for the moment, that the period of interest falls outside the ratings - but then, why is paleoclimate a category at all, if not because lessons from the geological past have implications for today?)
nealjking,
In fact, if I had to guess at the author's opinion, I would point out that he seems to use the global climate models (GCMs) with great confidence. So, I would guess that he would be likely to be confident about applying GCMs to the present-day climate as well:
I think most climate scientists would agree that anthro CO2 has caused a significant amount/most of the global warming for the last 50 - 100 years. But are they rating their papers or giving a vote according to their general opinion? This paper did not assess the validity of GCMs for current conditions.
Any case, Cook et al gave it a 3 based on the abstract, which I don't think is supportable when you consider options 5 and 6. How could the abstract not be seen as minimising the role of CO2, considered in the geological period they investigate? Alternatively, how could it not be marked a 4 if the time period is inapplicable?
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John Hartz at 10:40 AM on 31 May 2013Uncertainty no excuse for procrastinating on climate change
William Haas: Your most recent comment was a moderation complaint and was therefore deleted. Please loose the sarcastic tone as well. You should be able to answer the questions posed by Dikran Marsupial without repeating yourself.
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LarryM at 10:12 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
noelfuller and Composer99: There is also an updated heat content graph. You might also like the Global Warming Components infographic.
For readers who haven't visited the SkS Climate Graphics page in awhile, they have been updated by adding informative captions, and links to SkS material that references each graphic. So, browsing the Climate Graphics page provides an informative inroad into the wealth of SkS material.
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William Haas at 08:21 AM on 31 May 2013Uncertainty no excuse for procrastinating on climate change
Tom Dayton #19
The article says that the last IPCC assessment on climate change was made back in 2007. That was more than 5 years ago. The authors apparently feel that there are inadequacies in the old models so they are offering their new simplified models. The article says, "we wanted to calibrate the key climate and carbon cycle parameters in a simple climate model using historical data ..." They talked about 50 years. I am saying that their simulation would be a lot more credible if they calibrated it over a 150 year period.
Moderator Response:[JH] You have articulated your position more than once now. Plese note that excessive repitition is prohibited by the SkS Comments Policy.
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Tom Curtis at 07:47 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
tcflood @16, details on the operaton of Argo floats can be found here. As you will note, the Argo floats measure temperature from 0-2000 meters in depth. Other systems are used for temperature (and hence OHC) measurements below that depth. Some continue to be used above 2000 m, but they are nowhere near as numerous as the Argo floats.
For actual OHC data, the NOAA National Oceanographic Data Center (NODC) is the best first stop.
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tcflood at 07:36 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
Let me mention that I have also read Balmesda, Trenberth, and Kallen in their accepted for publication article "Distinctive climate signals in reanalysis of global ocean heat content." They make a point of comparing the OHC record with and without Argo data, and they get slightly less warming without Argo. I can't tell if the Argo data are synonymus with "data below 700m". Please help.
Moderator Response:[DB] See here for a discussion of BTK13.
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tcflood at 07:20 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
I just read John Cook's update of "It's Cooling" and most of the associated discussion over 2009-2011. I was struck in that discussion by the unsettled business of how OHC below 700m was measured. I was particularly confused by the discussion around how good the Argo data are and the different ways the data is massaged. Is there a good place I can do to get the latest on how the deep sea heat content science is going?
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KR at 07:15 AM on 31 May 2013It's CFCs
Ah, yes, the International Journal of Modern Physics B, the journal that is supposedly focused on condensed matter, statistical, and applied physics, the journal that published the amazingly wrong Gerlich & Tscheuschner paper.
A new paper in which the author claims that CO2 forcing is saturated, that the log relationship between concentration and forcing for CO2 no longer holds. Oh my...
I would suggest taking climate papers from IJMPB with a large grain (perhaps a block?) of salt.
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EOttawa at 06:55 AM on 31 May 2013It's CFCs
And another paper by the same authour, just published in International Journal of Modern Physics B
Cosmic-Ray-Driven Reaction and Greenhouse Effect of Halogenated Molecules: Culprits for Atmospheric Ozone Depletion and Global Climate Change
http://www.worldscientific.com/doi/abs/10.1142/S0217979213500732
and
https://uwaterloo.ca/news/news/global-warming-caused-cfcs-not-carbon-dioxide-study-says
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dana1981 at 06:35 AM on 31 May 2013The 5 characteristics of global warming consensus denial
Note - I'll withdraw my complaints about the quoting of our private discussions if Brandon and Watts and co. send me all of their email correspondences over the past year and a half.
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dana1981 at 06:33 AM on 31 May 2013The 5 characteristics of global warming consensus denial
The utter lack of ethics shown by Brandon and Watts and co. in reading and publically quoting material stolen from our private discussion forum really irritates me. Brandon is trying to dispute my assertions with stolen private comments I made what, a year and a half ago, before the ratings process began? Give me a break. It just shows they're not acting in good faith (shocking, I know).
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Tom Curtis at 06:03 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry @237, the issue in rating abstracts or papers are the implications regarding the warming from 1900 to 2012, and in particular the implications for the period from 1950-2012 where that can be distinguished seperately. In this case the implications are that rising CO2 causes warming.
The implication about changed ocean circulation are not relevant because the cause of that change is so distinct from anything hapening in the 20th century that it has no direct implications for the 20th century. This is particularly the case as the changed heat transfer due to ocean circulation is merely assumed in the paper as, "... effective full ocean models are not yet available, and the static mixed layer models used in some GCM experiments generate high SSTs that are inconsistent with temperature estimates made using the the geological record." (p 545)
The potential effects of "ground hydrological schemes" are also irrelevant as they are a feedback, not a forcing.
Consequently, of the trio of potential factors that could improve the modelling (according to the abstract), only one is directly relevant to 20th century temperatures; and hence only one can impact on the rating. That one is the influence of CO2. You are then left with the fact that the abstract and paper both indicate that CO2 influence temperature, but do not provide sufficient information to estimate whether that influence is likely to represent at least 50% of warming over the period 1900-2012 or 1950-2012. Hence a (4) IMO.
The only way you could rate the paper or abstract as rejecting the consensus is if you:
1) Forget that it deals with Jurassic continental distributions and hence has no implications for heat transport in the twentieth century;
2) For the paper, forget that the SST changes are imposed rather than modelled (note that this is not mentioned in the abstract, and nor is the generation of the model which cannot be derived from the year which is strictly not available for abstract ratings); and
3) For the paper, forget that the effects of doubling CO2 shown are for a state in which the majority of the feedbacks of the doublings have already been imposed in the initial state,ie, that the additional warming is for direct radiative heating only where some of the direct radiative heating overlaps with that from the pre-existing increased water vapour content in the atmosphere.
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Dikran Marsupial at 06:02 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
FWIW, the abstract of the Chandler paper clearly implies that CO2 should be expected to cause warming. A corollary of this implication is that anthropogenic CO2 emissions sould be expected to cause warming. Suggesting that ocean heat transport can explain the relatively warm Jurassic without CO2 does not logically contradict that. Rating the paper as a three sounds reasonable to me, although the implication is not as direct as in some abstracts.
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william5331 at 05:32 AM on 31 May 20132013 SkS Weekly News Roundup #22A
Perhaps we should try to emphasize the other effects of burning fossil fuel other than climate change.
http://mtkass.blogspot.co.nz/2010/10/forget-climate-change.html
It's really a no brainer.
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Don9000 at 05:30 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
I think one very interesting point Dr. Trenberth makes is that scientists are documenting new developments in the Pacific, which are connected to the El Nino/La Nina/ENSO cycle. My sense is that the extra energy makes models of cyclical events like the ENSO cycle, which are developed based on data gathered at earlier, lower-energy times, at least potentially suspect. It may be that we are headed for a significant old-fashioned El Nino event in the near future, but on the other hand it may be that the increase in heat content will result in a change to the way the ocean gives up its extra heat that might not fit the way we have come to define the El Nino phase of ENSO.
If the wind patterns have changed and have pushed energy into deeper waters, it seems completely plausible to me that the location/duration/intensity of any future warm water upwelling might also change, which would in turn make further significant changes in the climate likely.
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nealjking at 04:48 AM on 31 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
I would give the paper a 3: It doesn't really say ANYTHING about current climate trends, it seems to be restricted to the era 180 million years ago. That he concludes that CO2 may not have played much of a role in the particular warming then actually says nothing about what he would say about the warming now.
In fact, if I had to guess at the author's opinion, I would point out that he seems to use the global climate models (GCMs) with great confidence. So, I would guess that he would be likely to be confident about applying GCMs to the present-day climate as well: and since today's application of GCMs lends credence to the importance of CO2 (today), I would speculate that the author actually would likely support the consensus opinion, which is strongly supported by the GCMs.But this is going beyond what is directly available in the paper. I would give it a 3, definitely not a 4 or a 2.
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MMM at 04:38 AM on 31 May 2013What causes Arctic amplification?
Another very recent paper:
http://www.cgd.ucar.edu/cas/cdeser/Docs/submitted.screen.arctic_forcing.mar12.pdf
This is perhaps closer to the original post - it finds that half of the Arctic surface warming is due to sea ice/sea temperature changes, with a sixth coming from remote transport due to sea surface temperature changes elsewhere... and it isn't clear where the remaining third comes from. The paper claims that changes in direct radiative forcing mainly matter for summer tropospheric changes.
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MMM at 04:10 AM on 31 May 2013What causes Arctic amplification?
Sigh. I'm trying to find a good explanation for NON-albedo driven Arctic amplification, but this post isn't it. In fact, I feel like this post summarily dismisses these other mechanisms based on a single paper, which is not appropriate: certainly, both the IPCC AR4 report or the draft AR5 report indicate that these other mechanisms may be responsible for as much as or more than half of the amplification. Work that might be relevant includes:
http://www.esrl.noaa.gov/psd/people/amy.solomon/pubs/Solomon_GRL_2006.pdf : Showing a link between basically thunderstorms and polar amplification
http://onlinelibrary.wiley.com/doi/10.1029/2005GL025244/pdf : surface albedo contributes but does not dominate amplification
http://yly-mac.gps.caltech.edu/AGU/AGU_2008/Zz_Others/Li_agu08/LangenAlexeev2007.pdf : Arctic amplification is observed in an idealized aquaplanet GCM
http://link.springer.com/content/pdf/10.1007%2Fs00382-009-0535-6.pdf : Perhaps the clearest explanation, using a locked-albedo model to explore how water vapor and cloud feedbacks as well as changes in heat transport and vertical stratification enhance Arctic warming.
-MMM
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Composer99 at 02:25 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
I believe Skeptical Science has produced one or two versions of just such a graph over the years.
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Rob Honeycutt at 02:12 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
I think the next few years are likely to be pivotal with regards to the whole climate issue. My takeaway from this article from Dr Trenberth suggests that we're likely at the end of a 15 year hiatus, and should anticipate another rapid rise in global surface temps.
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michael sweet at 02:01 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
Wallenburg,
Look at the lines on the graph. The flat areas you question run to the start of 1986 and from the end of 1987. The temperature rose rapidly during the start of 1987. You look like you are just arguing to argue when you question Dr. Trenberth in this way, expecially since the graph clearly shows the hiatus periods that he is referring to.
Dr. Trenberth: thank you for your contribution. It helps us to keep our discussions on track when scientists tell us what they think. -
Rob Honeycutt at 02:00 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
Wallenburg... You can clearly see the three 10 year hiatus periods identified in the graph.
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Wallenburg1930 at 01:25 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
Dr. Trenberth writes: There are three ten-year periods with a hiatus warming: 1977 to 1986; 1987 to 1996; 2001 to 2012. Remarkably, because there is not a year between 1986 and 1987. Was there a warming hiatus between 1977 and 1996?
No, in fact (looking at the graph) there was a strong rise in temperature in that period. Dr Trenberth is apparently wrong.
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MA Rodger at 00:42 AM on 31 May 2013Global warming is here to stay, whichever way you look at it
I think it should be mentioned that of the three 'hiatus' decades mentioned in the post, only the present one doesn't include a large cooling volcanic eruption (El Chi'chon 1983, Pinatuba 1991).
But do we need a volcano for a 'hiatus' decade? My back-of-fag-packet calculations of what has been happening within the last decade puts the drop in solar energy at about equal to the rise in GHG forcing over the period, and the increase in ice melt from ice caps and sea ice also about equal energy-wise to the absent surface warming.
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