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Chris8616 at 17:53 PM on 23 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
Polar jet stream, is maybe a bit confusing sicne the southern antarctic oscillation is also a polar jet stream?Polar air intrusion during the winter because of the higher jet stream amplitude. The UK will likely expereince much more pronounced floods, with Jet Stream blocking patterns, when the rain system just keeps sitting there.What about downward bursts/microburst? Greenland is according to Jennifer Francis a prime spot for blocking patterns to occur, see Sandy - caused 90 degree turn.Where exactly is the Jet Stream, if not with the Jetstreaks? Are these visible from the ground - do they come with clouds or is this different?In regards to tornadoes and Jet Stream:“As with hurricanes, I think frequency needs to be separated from intensity.Climate change increases the available energy for tornadoes through a warmer and moister atmosphere. Wind shear decreases in the global mean, but this might be irrelevant locally when the jet stream dives southward like it did last weekend across the Plains.“I believe there is evidence that the strongest tornadoes are getting stronger. They are certainly getting longer and wider.” - James B. Elsner, an atmospheric scientist at Florida State University Humid air and the Jet Stream help to fuel more intense thunderstorms/tornadoes -
s_gordon_b at 15:04 PM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I'm having a problem interpreting this study. The banner conclusion is that "among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming." But in the Results section it states: "To simplify the analysis, ratings were consolidated into three groups: endorsements (including implicit and explicit; categories 1–3 in table 2)..." This is where I'm experiencing a disconnect. Categories 2 and 3 are too ambiguous - as defined in table 2 - to equate to the consensus that humans are not only a cause of industrial era global warming but the dominant cause since the middle of the last century (at least). Am I not reading that right? And if so, shouldn't only those abstracts that take an unambiguous stand on the consensus of dominant human causation be counted and the others excluded in the same way that abstracts that take no stand at all were excluded?
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scaddenp at 13:51 PM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I think this confounds physical and statistical modelling but I will look at the paper. The success of more recent techniques (like F&R) would strongly suggest that this paper is mistaken. The indices might be an imperfect measure of the large scale process, but they are good enough for predicting unforced variation in global temperature due to ENSO.
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DSL at 13:48 PM on 23 May 2013On the value of consensus in climate communication
I don't have much to say. Kahan's points are fair, but they're also academic. No actual model for communication is given, other than a link to a page that has, near the bottom, something useful--the ambivalent partisan approach or mode. Cook makes good points as well, but he's responding to a game being played behind the curtain, one that Kahan never really addresses. Indeed, that game should be fully recognized in any strategy for moving the public on this issue. The other players are trained in rhetoric and have absolutely nothing to lose. It's as if they play the game with a full deck and science is limited to no face cards (and aces count as 1).
Detailed, practical approaches need to be available to anyone who is willing to enter "the trenches." The "ambivalent partisan" mode is one I try to emulate, with a few additions. More powerful than ideology is the need to remain valuable, and that need is amplified when the discussion is public. No one wants to be dismissed out of hand--to be categorized, labeled, boxed, stamped as innocuous. I will only once in a blue moon use any sort of label, including "denier," when I speak with people in a general public forum on this issue. I ask questions, and not questions that have a rhetorical edge, but well-explained questions that invite the interlocutor to express a speculative opinion. No ivory tower. I try to give uncertainty when it exists. It's better to provide and discuss uncertainty than it is to leave it out. Tom Curtis is very good at that, and I think to the consternation of a few other SkS regulars. Also, as Kahan points out with the example of Hayhoe (though he gums it up with academic jargon), it's better to step into someone's else's castle and recognize it as a valid construct than it is to remain in your own castle and stand at the battlement throwing taunts and unexplained bits of heavy science. I've had good success with this general approach (a variety of private FB messages/emails thanking me not for explaining things but for doing it in a way that wasn't antagonistic. I often get the "I'll respond to you because you seem like a reasonable person." That's the response I aim for.).Ultimately, the Cook study is only valuable to me as a conversation starter and a casual debunking of the "there is no consensus" myth. I think Kahan doesn't understand that there are a great many people who don't understand the greenhouse effect and who are susceptible to suggestions that AGW is something different than the greenhouse effect. That's really what the consensus is all about for me as I find myself discussing it in various places. People aren't sure what points of the theory the consensus is providing agreement on, and so they respond to it as they do to every other article talking about global warming. In other words, the consensus doesn't mean anything specific. It's like how the word "catastrophic" is used in professional "skeptic" circles--it means whatever you need it to mean at the moment.
A bit rambling. Sorry. I started out with my two cents and it turned into a pfennig, a pence, and half a yen (to revise it).
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jmorpuss at 11:40 AM on 23 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
Nice John
One thing I thought might add more understanding to your post would be to include some sort of acknowladgement and recognition for this natural interaction process. http://en.wikipedia.org/wiki/Electric_force I tried a site search but could not find any reference to Coulomb's Law so link is provided.
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MS1 at 10:30 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
#46 scaddenp at 08:54 AM on 17 May, 2013
"MS1 "I think their paper failed " really?... If the ENSO index was substantially flawed or there was significant non-linearity, this isnt born out by the success of their prediction. If you believe that the prediction can be improved significantly by other indexes or method, then show us."
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Compo et al 2010 have addressed this issue.
http://www.esrl.noaa.gov/psd/people/gilbert.p.compo/CompoSardeshmukh2008b.pdf
"Because its [ENSO's] spectrum has a long low frequency tail, fluctuations in the timing, number and amplitude of individual El Nino and La Nina events, within, say, 50-yr intervals can give rise to substantial 50-yr trends..."
"...it also accountd for an appreciable fraction of the total warming trend..." (see figure 9b )
"...It [The Pacific decadal oscillation or the interdecadal Pacific oscillation] is strongly reminiscent of the low-frequency tail of ENSO and has, indeed been argued to be such in previous studies (e.g. Alexander et al 2002, Newman et al 2003, Schneider and Cornuelle 2005, Alexander et al 2008)..."
"...In this paper, we have argued that identifying and removing ENSO-related variations by performing regressions on any single ENSO index can be problematic. We stressed that ENSO is best viewed not as a number but as an evolving dynamical process for this purpose..."
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Dumb Scientist at 10:26 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Farmer Dave @24: Last year I noted that the deep ocean's heat capacity is much larger than the cryosphere's. So I think Kevin C was right to focus on the warming deep ocean purely on thermodynamic grounds.
I mentioned melting land and sea ice not because of their total effect on surface temperatures, but because those independent measurements also confirm that the climate is still gaining heat, even over the last 16 years. Here are relevant links and a short movie.
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JasonB at 09:50 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
Rather than going round and round in circles arguing over definitions, let's make this concrete:
Earlier you claimed that there is a difference in meaning between the wording in the graphic and the wording in Dana's example of a paper that would be classified as endorsing the consensus ("we are the cause" vs "we are causing").
I propose a test: Can you give any examples of abstracts that were rated as level 2 or level 3 that you feel do not endorse the statement in the graphic?
If your argument is correct, there should be papers that you feel do not support the claim and based on the number of them we can ascertain the impact that would have on the results.
Note that unless you're going to do an exhaustive search, you need to count how many papers you looked at as well as how many examples you found. This is so we can get a percentage that can be used to estimate the impact. You can also propose what you view as the "correct" classification for the examples you find.
Until then, this argument is merely academic.
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william5331 at 09:47 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Being completely unscientific and speaking anthropogenically, Gaia is fighting back and keeping the temperature constant. A sort of light switch phenomenon. Look out when we have pushed the switch beyone Gaia's capacity to thermo-regulate. The next time we have an El Nino should be interesting. Sept 15, 2016 likewise.
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Farmer Dave at 09:32 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Dumb Scientist @2
I agree with your question about the impact of ice melting on reducing the rate of air temperature increases. I presume that earth energy balance models include the latent heat required to achieve all the ice melting we have seen over the last few years. Does anyone know of any estimates of the effect the melting has had on moderating changes in sensible temperature over, say, the last decade?
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william5331 at 09:26 AM on 23 May 20132013 SkS News Bulletin #13: Alberta Tar Sands and Keystone XL Pipeline
You have to agree with the article on Canada. Even if the heads of their government officials are so far up where the sun doesn't shine that they can't recognize the disaster they are helping to cause, at least they could be accute business men. Why on earth would Canada send raw oil, only just separated from the sand, to the USA for them to make most of the profit. As the writer says, Canada is seeing precious little benefit from the exploitation of it's resource. They should be pipeing or trucking refined petrol, diesel and other products to the US. As far as her ecological record goes, look at how she has destroyed her east coast fisheries resources through glaringly faulty science and through bowing to the very short term interests of her fishing companies. They behave like grasshoppers rather than ants (aesop fables) and show zero intestinal fortitude. They went so far as to try to shift the blame onto the seals for the decline in their fisheries resources and actually subsidized seal hunters when the immages of the slaughter of baby seals trashed the fur market. If you want an account of the stupidity of successive Canadian governments, get Sea Of Slaughter by Farley Mowat.
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Rob Honeycutt at 08:59 AM on 23 May 2013It's satellite microwave transmissions
grindupBaker... I'm really unclear on what you're attempting to say.
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Esop at 08:57 AM on 23 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
Brilliant article. Very informative!
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Dumb Scientist at 08:55 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Mod: please delete #99. Dunno why it came out empty...
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Dumb Scientist at 08:54 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Just to be clear, my comment #96 didn't refer to Dikran's comment #95 above. I linked to Dikran's comment on another page which is much more interesting.
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Dumb Scientist at 08:52 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
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KK Tung at 08:33 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to post 95 by Dikran: I liked your work investigating the effect of the change in baseline offsetting on the apparent model uncertainty.
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KK Tung at 08:24 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply post 95 by Dikran and post 96 by Dumb Scientist: I like the tone of our exchanges now. To understand the point I was trying to make, please first do not view my comments as saying there is anything wrong with the IPCC models. My comments concern the forced response vs internal variability. Since I do not know what the forced response is in the observation, I was using the model ensemble mean as a proxy for that. In fact this is an assumption that the model is perfect. Now we cannot do ensemble mean of the observation, because our climate is just one realization and we do not have the other ensemble members. So we cannot compare observation's forced response with the model's forced response. My statements were never intended to be a comparison of the two and see if the models are correctly simulating the real forced response. Subject to the caveat of my assumption of perfect models, my statement concerns the presence of internal variability. When the observation is below the model ensemble mean, I tentatively suggest that the explanation could be that there is an internal variability that is in a cool phase in the observation but is not (and should not be) in the model ensemble mean. The point I made previously was why we need it now during the hiatus period and not during the period of accelerated warming.
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scaddenp at 07:52 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
rhJames - firstly, a consensus does exist. Secondly, while a consensus is not proof of a theory, it is the only reasonable basis for public policy so it is important to know what it is.
"Lets stick to the scientific evidence" _ well I wish deniers would but they instead prefer blog "science", cherry picking and misrepresentation. Cook13 is effectively a survey of the published scientific evidence.
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grindupBaker at 07:45 AM on 23 May 2013It's satellite microwave transmissions
Rob Honeycutt #26 This is true but I have a single-tasking mind and like to keep the waters clear by considering physical realities as the indifferent entities that they are as much as I can. If I can ever manage to grasp them, might move on to spiritual & socio-political. I've scaled mentally by 5,000,000 because I can picture the Earth sphere knocking a small hole in the ceiling with the electromagnetic shining in, 1/8" 90% air, 1/20" oceans, gently warming until they lap the ice away, burping disasters across the land, and so on. It's a human scale.
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Dumb Scientist at 07:32 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dikran Marsupial has performed an analysis which is relevant to this conversation.
Dr. Tung, if you'd like to comment on Dikran's method, we'd all appreciate your insight. Thanks.
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Rob Honeycutt at 07:15 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I have to say, one of the most compelling aspects of Cook13 is that the resulting consensus figures for the SkS rated papers almost precisely match the consensus figures coming out of the scientists' self-ratings. (97.1% vs 97.2% respectively)
If there was ever a great example of self-skepticism, this was it. John Cook made sure that we tested our own biases here at SkS against the evaluation of the scientists themselves. And not just a few cherry picked scientists. We tested against a very large number of scientists.
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Rob Honeycutt at 07:03 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
rhjames said... "Let's stick to scientific evidence."
You seem to be operating under the erroneous assumption that Cook13 is a survey of scientists (a "show of hands"). It is not. It is a survey of the published research.
It's entirely likely that there is research within the survey that reflects different positions on papers coming from any one scientist. A researcher that has published a large body of research could potentially have papers that fall into each of the 7 endorsement categories. Certainly most of the researchers who have multiple papers in the study have them falling into at least two or more of the categories.
So, really, the opinions of the scientists themselves matter little. What matters is what their data show.
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John Russell at 07:00 AM on 23 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
If anyone wants to keep track of the jet stream position over the N Atlantic/UK on a daily basis, I've found this site to be very useful.
Damn good article, by the way. I'll be coming back. Thanks for the hard work, John M.
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Composer99 at 06:41 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Claims identical to yours have been examined before and rightly dismissed, for three reasons.
First, most orthodox or consensus positions before the scientific revolutions in various disciplines were not based on anything like as rigorous the methodologies used to generate consensus positions in the sciences today, and are an inappropriate point of comparison. Who cares whether or not there was a consensus about bloodletting in the past? The consensus about AGW is comparable to the consensus of other contemporary scientific topics: quantum mechanics, relativity, and the like. (*)
Second, the consensus of experts follows from the preponderance (or, if you will, the consensus) of the evidence, a point that has been raised on several occasions on this thread and any other occasion where the scientific consensus has been discussed.
Third, research shows that the public perception of the scientific consensus is an important component of public advocacy for action to reduce emissions and mitigate global warming. So it is in fact critical, if we want to avoid the worst consequences of rapid global warming, to spread the word about the consensus.
(*) In point of fact I have a hard time thinking of any case where a scientific consensus, in the modern sense, of over 90% of scientists has arisen that has actually been overturned, with the possible exception of what caused gastric ulcers. In past cases either the consensus was non-scientific, or there was no consensus position to speak of.
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Kevin C at 05:51 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
It has been suggested that we leave the video up but add annotations to explain where the problems are. This would retain the educational content (and in practice probably enhance it, because learning often progresses through correcting wrong understanding).
But the big advantage is that everywhere the video has been embedded the annotations will now be visible.
However, John is pretty busy with at the moment, so it may take a week or two.
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Kevin C at 05:47 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Keith: I wouldn't include ocean heat uptake in a fitting calculation, but it's the sort of effect you might detect more clearly having removed the other terms. In otherwords, a change in trend.Troy is working on doing this without using fitting methods, which means you don't have to assume the warming signal and thus gives you a much better basis for detecting changes in the warming signal.
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Dumb Scientist at 05:26 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
jdixon1980: The total energy content of the climate system needs to be stressed much in the media. I've been making this point since 2009, and many of my colleagues have made similar complaints. So I'm inclined to place the blame on the media rather than on scientists.
Imagine filling a measuring cup at a constant rate while the water sloshes around. Sometimes the water will pile up against the side of the cup that doesn’t have the measuring tick marks. As it piles up, the water level against the tick marks might go down even as the faucet pours water into the cup.
In this analogy, the water level in the cup is the Earth’s total energy and the constant water flow is the extra radiative power added by human emissions. The side of the cup with the tick marks is the Earth’s surface, where most of our temperature sensors are. The other side of the cup is the deep ocean, which we can’t measure as well as the surface.
Water sloshing towards the tickmarks is like a temporarily warm El Nino, while water sloshing away from the tickmarks is like a temporarily cool La Nina.
Humans add extra water to the cup, but it sloshes around the cup naturally.
Humans add extra energy to the Earth, but it sloshes around the Earth naturally.
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John Hartz at 05:20 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
@Barry #189:
You state: I'm discussing the academic merit of the Cook et al study.
What exactly do you mean when you use the phrase, "academic merit"?
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keithpickering at 04:32 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Is it really correct to include both ENSO and ocean heat uptake changes? Aren't these pretty close to measuring the same thing?
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Dikran Marsupial at 04:15 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
Dumb Scientists yes I agree, however we need to determine if the basic approach is mathematically sound before worrying too much about the details!
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Miriam O'Brien (Sou) at 04:09 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Jdixon1980, is this what you are looking for?
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Dikran Marsupial at 04:04 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Prof. Tung I do not understand the point you are trying to make with this image.
Nobody should expect the observations to lie any closer to the ensemble mean than is indicated by the spread of the model runs (as I have stated before). Note that in 1998 the observations were closer to the (upper) boundary of the 95% than current observations are to the lower boundary. However the 1998 event was not evidence that the ensemble mean was not a good approximation of the forced response, so I see no reason to think that the current observation-ensemble mean difference is indication of a systematic issue, but is probably just internal variability. Of course we are also interested in the physics of internal variability.
The diagram I gave uses the model projections actually used in AR4 and uses the same baseline period that is used in making the projection. Do you agree that it shows that the observations are consistent with the model projection, yes or no? If "no" please explain what is defficient in the figure I presented here.
Note that the choice of baseline has a large effect on the apparent uncertainty of the observations and the models at the boundaries of the baseline period. I suspect this is the issue that James Annan mentions on the twitter thread. Compare the width of the model spread using the two different baseline periods
Note the observations are less close to the edge of the model spread if the longer baseline period is used, as the baselineing procedure minimises the differences between models in the baseline period. The longer the baseline period, the less this can over-fit the variability within the baseline period, so less of the model uncertainty is attenuated.
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Rob Honeycutt at 04:00 AM on 23 May 2013It's satellite microwave transmissions
grindupBaker... But it would be the change in the Earth's climate system that matters to us tiny beings living on the planet's surface.
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Dumb Scientist at 03:56 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
Thanks Dikran! I have to rush off to a talk, but I wanted to nitpick: our CO2 emissions are rising faster than exponentially. Anthropogenic forcings might be rising quadratically...
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KK Tung at 03:34 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Still can't insert. But the figure can be found here.
https://twitter.com/ed_hawkins/status/299161479268139009
Moderator Response:[Dikran Marsupial] Image added, on my browser (Firefox) clicking over the image on the Twitter brings up a menu with an option to "view image", which loads the image in a new tab on the browser, which then gives a URL that you can use with the SkS image widget. I suspect other browsers have similar functionality but I only use Firefox myself. HTH
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KK Tung at 03:33 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
I am still having problem inserting figures. I was able to insert a pdf but not a powerpoint figure previously on this site, but no more. I also don't have a server where I can host. SkS need to fix this problem.
I managed to find one figure, the one by Ed Hawkins, on his own twitter site. MA Roger's comment on the person who sourced Hawkins' figure is irrelevant. I thought it better to use a direct source and bypass the second quesssing of the motives of the person who sourced it.
Moderator Response:[Dikran Marsupial] I have sent an email suggesting an interim solution. I will raise this issue with the other SkS moderators. I don't think powperpoint images are directly supported by browsers, so perhaps converting it to png, jpg gif etc may resolve the problem.
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KK Tung at 02:49 AM on 23 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
[image deleted]
Moderator Response:[Dikran Marsupial] I'm sorry Prof. Tung, SkS doesn't support uploading images to the site, only linking to images that are already hosted on other sites already. Perhaps the easiest approach would be to place them on your own webserver and then link to them here, or possibly use one of the photo sharing services, such as flikr (which is what I have to do for another blog to which I occasionally contribute). Specifically, the data for the image cannot be part of the URL.
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Rob Honeycutt at 02:32 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Jason said, "Next we'll be arguing what the meaning of "is" is!"
Exactly. At this point Cook et al 2013 is part of the published research on this matter. If there are people like Lucia and others who wish to challenge the findings, they should do so by the way of publishing their own paper.
They are more than welcome to craft their own methodology to test the level of consensus on AGW. But, like with the hockey stick, I think the results they would get would go against the conclusions they want to see, and to get the conclusions they'd prefer would require contortions that would not pass peer review.
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grindupBaker at 01:51 AM on 23 May 2013It's satellite microwave transmissions
I only started looking at "Global Warmage" for science & math interest 3 months ago. I linked here from a 2013-05 post about revised AST processing. Oh boy. They have absolutely no concept whatsoever of the orders of magitude difference between the vast energy delivered non-stop to Earth by the sun & the trivial bits shoved around on Earth surface. Signs are that this inability to grasp simple quantity concepts is endemic among the public at large.
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jdixon1980 at 01:49 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
A helpful image could be somebody on an elevator going up while playing with a yo-yo - the height of the yo-yo goes up and down, and might be above or below the hand at any given time, but it's average height is increasing just as quickly as the average height of the hand.
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jdixon1980 at 01:44 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
DS @2: "As you say, the total energy content of the climate is a more direct measure of global warming."
One thing that bothers me about the way the warming trend is presented to the public in the MSM is that whatever is happening with surface temperatures is always the focus of the headline and the focus first several paragraphs, if not the entire article. If there is any mention of total climate energy content, it is usually buried in a later paragraph and not represented in a prominent figure, such that I would venture to guess that most casual media consumers skim over it, if they even get that far in the article before moving on to something more scintillating. A perfect example is the recent Economist article on climate sensitivity (http://www.economist.com/news/science-and-technology/21574461-climate-may-be-heating-up-less-response-greenhouse-gas-emissions), which, when it finally addresses ocean heat content about midway through the article, focuses on the top 700 m with an accompanying graph showing a flattening (but still positive) temperature trend, and only mentions the Balmaseda et al. study of trends in the total ocean temperature profile as an afterthought.
Do you think that climatologists need to do a better job of conveying the greater long term significance of total climate energy content (as opposed to surface temp fluctuations) to the MSM, so that the MSM might focus more on the significance of total climate energy?
Would it help to use more or better analogies of ocean heat content to something intuitive and mechanical, like Verner Suomi's famous "great and ponderous flywheel," but maybe not so lofty? What about the ocean heat content as a "hand" and surface temperatures as a "yo-yo," which can go up and down but is always tethered to and pulled back towards the hand?
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JasonB at 01:38 AM on 23 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
I'm making no claim as to what the consensus statement is meant to be.
You said "there is no doubt that the consensus is that human activity is causing at least some global warming". Cook et al's results are far stronger than that, as I already explained.
I don't know how many times I can keep saying this; the original authors were asked whether their papers endorsed AGW. The results are being reported as the percentage of papers that endorse AGW. There is no discrepancy. What the general public wants to know is "is human activity causing global warming?". That's exactly the statement that the authors of 97.2% of the papers that expressed an opinion on the matter said their paper endorsed. QED.
Moderator Response:[JH] Be careful of excessive repitition.
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Miriam O'Brien (Sou) at 00:19 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
Kevin, I particularly like your animation of the possibly different effects of the volcanoes. I expect that each large-ish volcano can have different effects on climate to some extent, depending on what part of the world it erupts in, time of year etc. So that looking at other eruptions won't necessarily give an answer to what happened in any other case.
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Miriam O'Brien (Sou) at 00:13 AM on 23 May 2013Has the rate of surface warming changed? 16 years revisited
@JohnRussell I wouldn't worry too much about what Bob Tisdale says. He's a one-trick pony just going on about ENSO jumping up and down and leaping and cavorting with 'natural' but completely unexplained magical warming (by Bob himself, that is). I've noticed many of the WUWT faithful don't put much credence on him these days. He's missed the main point that Kevin is making altogether in his haste to push his ENSO barrow.
I don't have a view one way or another on the video. I found it useful myself but didn't take it to be the last word on the subject (nothing ever is). Still, I'm happy to wait to see what new science comes out over coming months. Or for Bob T's El Nino - maybe next year? I wouldn't be surprised if it's a doozy when it comes.
I have to say articles like this are refreshing. It forces one to think about things more and realise that there is a lot to consider when it comes to what climate change will bring - and when.
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Dikran Marsupial at 23:56 PM on 22 May 2013The anthropogenic global warming rate: Is it steady for the last 100 years?
I thought I would have a go at testing Prof. Tungs method via a simple thought experiment, where we can have ground truth. I've used MATLAB, so I'll add code snippets and diagrams as I go. I should however point out that it is possible that I have misunderstood the method, in which case hopefully setting things out very explicitly will help Prof. Tung to identify where i have gone wrong.
Lets assume that that anthropogenic emissions have been rising quadraticaly
anthro = 0.00002*(T + T.^2);
where T is time and goes from 1 to 150 years in the diagrams shown below. Rather than model ENSO, volcanic activity and solar forcing separately, for convenience, we can lump them all together as a single term "natural", and we will make it sinusoidal to keep things simple.
natural = 0.1*sin(2*pi*T/150);
For the sake of this thought experiment, I shall assume that AMO actually has no effect at all on global mean surface temperatures, so the observations are an equal combination of anthro and natural and some additive Gaussian noise
observations = anthro + natural + 0.1*randn(size(T));
Now lets assume that AMO is actually a consequence of anthropogenic and natural forcings/variability, so it is correllated with the observations, but only because the observations and AMO have shared causes.
AMO = 0.4*anthro + 0.6*natural;
Now this presents a stren test for Prof. Tung's method, but if his method is sound, it ought to still be able to deduce the correct anthropogenic forcing even in this case. If we plot everything, we get this:
Note I have set up my thought experiment, so the observations are vaguely similar to the actual observations.
The next step is to linearly detrend AMO, which can be easily achieved via linear regression:
X = [ones(size(T)), T];
beta = (X'*X)\X'*AMO;
AMOd = AMO - beta(2)*T;
Plotting the detrended AMO gives this:
Now linear detrending obviously does not remove the all of the effects of anthro from AMO as anthro is quadratic. Also if natural has a linear trend over the period considered, then that also will have an effect on the detrending.
We can now perform the regression analysis, where the means have been subtracted from the explanatory variables so that any offset in the observations are explained by the bias term, rather than using the explanatory variables.
X = [ones(size(T)) anthro-mean(anthro) natural-mean(natural) AMOd-mean(AMOd)];
beta = (X'*X)\X'*observations;We can look at the values of beta that we have extracted, and we find
beta = [0.1577; 0.6382; 0.1927; 1.1731]
Note that the regression model is using AMO to explain more of the variation in the observation than it uses anthro or natural, even though the observations are in no way causally dependent on AMO! The true set of regression parameters are:
beta = [0.1577; 1.0000; 1.0000;0.0000]
We know that by construction. This is a good illustration of why using regression methods for attribution is tricky. In this case, the problem is co-linearity. AMOd is correlated well with the observations, in face more so than anthro or natural are individually, and regression is a correlation based method.
We ccan then find the output of our regression model
model = X*beta;
and plot it, giving
So we can see that the regression model (blue) "explains" the observations (green) almost as well as the true model does.
The last step is to find the deduced anthropogenic forcing. My interpretation of Prof. Tungs explanation given in the post above is that we first find the residuals
residual = observations - model;
compute their least-squares trend
X = [ones(size(T)), T];
BETA = (X'*X)\X'*residual;and adding the trend in the residuals to the deduced anthro
infanthro = beta(2)*anthro + BETA(2)*T;
but if you do that, you get
where you can see that the deduced anthro is much less than the true anthro, which suggests that Prof. Tungs method is not reliable.
UPDATE: If we exactly deduct the anthropogenic influence on the AMO using
AMOd = AMO - 0.4*anthro;
then we get more or less the correct answer:
which suggests that the way in which the anthropogenic influence on the AMO is accounted for is very important, and linear detrending is unsatisfactory unless the anthropogenic forcing actually is linear.
I have also noticed that in both cases, the trend of the residuals is to all intents and purposes zero, so adding the trend of the residuals to a*anthro(t) as Prof. Tung suggests has only a negligible effect on the outcome.
Now I should stress, there are at least two possible explanations, either (a) Prof. Tung's method isn't reliable or (b) I have not propely understood or implemented Prof. Tungs method for my thought experiment. I try to be a self-skeptical sort of person, so I am assuming (b) is more likely. Hopefully Prof. Tung can point out the problem, providing MATLAB (or other) code for the thought experiment would be a really good way of getting his idea accross efficiently.
Moderator Response:[Dikran Marsupial] Oops, one error found already,
infanthro = beta(1)*anthro + BETA(2)*T;
should of course have been
infanthro = beta(2)*anthro + BETA(2)*T;
The penultimate figure has been updated to take this into account, sorry for the confusion.
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barry1487 at 23:48 PM on 22 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Jason,
I'm making no claim as to what the consensus statement is meant to be.
barry, the authors were asked to state whether or not their papers endorsed the proposition that human activity is causing global warming.
I agree. But if Authors rating at 2 and 3 (which comprise a huge bulk of the endorsement ratings) take that to mean anything between, say, 'some' influence and >50%, and Cook et al take it to mean >50%, then the rating criterion is different and this may signficantly affect the comparitive results.
Would I be correct in assuming you would say that options 2 and 3 rate the human influence on global warming as dominant (b)?
I'm hoping to garner clear responses to see if there are different interpretations by commenters here. Tom Curtis began as an author on Cook et al, but declined participation after a while. Judging by comments he has made at Lucia's he is saying that ratings 2 and 3 refer to >50% influence. Eg,
Lucia, excluding papers dealing with impacts and mitigation, 92.9% of papers surveyed (and that indicate a position in the abstract) implicitly or explicitly affirm that >50% of recent warming is due to anthropogenic causes.
http://rankexploits.com/musings/2013/on-the-consensus/#comment-113388
You write;
If they felt that their paper either implied or stated that human activity was a contributing factor but not the primary cause then they could have categorised their paper as level 5, 6, or 7, depending on how it was presented. (Remember, level 5 includes any proposition that something other than humans was the main cause, and level 7 includes any quantification less than 50%.)
Apart from 1 and 7, none of the ratings are quantified. The descriptors are "endorses" and "minimises" AGW. These are qualitative statements, and that was how I read them. That is also how Zeke Hausfather read them.
Categories 2 and 3 as well as 5 and 6 do not make any explicit assertion of attribution percent (e.g. they don’t assert < 50 percent, they simply don't provide enough information to imply a percent).
http://rankexploits.com/musings/2013/on-the-consensus/#comment-113263
That 2, 3, 5 and 6 relate to >/< 50% human contribution may be inferred in context, but other inference is also possible.
My point is, if reasonable people disagree on the ratings criterion (and the 2 I've cited are 'friendlies', there is yet more disagreement between other parties), then original Authors may have had different interpretations, and this may well undermine the comparitive results that are a strong corroborative feature of the paper. The similarity of results could be a fluke.
The only way to test that, that I can think of, is by asking the original Authors who rated their own papers what they assumed the criterion was for 2 and 3 (and 5 and 6).
If the point of the paper is to demonstrate there is a consensus that more GHGs in the atmosphere should cause some warming, then that is not as impactful as endorsing the IPCC statement. It's a much lower bar with a much smaller target audience. None of the contrarian climate scientsts dispute that, and neither do most prominent skeptics (including Anthony Watts, for example) and most of their followers.
The basic message is fine - and the effort has been successful on that regard. I'm discussing the academic merit of the Cook et al study.
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KR at 23:46 PM on 22 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry - "And yet, KR, the ridiculous interpretation is how many reasonable people have taken 2 and 3."
Reasonable people? Perhaps... But many of the people raising this issue (this obfuscation, in my point of view) are not climate scientists, and are not as aware of the IPCC reports. Or at all fond of of the IPCC and its conclusions, for that matter (cf motivated reasoning).
"Can you explain why abstracts saying "human greenhouse gas emissions are causing global warming" means that they are, perforce, positing >50% human influence?"
As I pointed out above, because the category titles are part of the description as well, and because, quite frankly, anyone familiar with the science knows that AGW means human caused global warming:
Definitions of each level of endorsement of AGW.
- Explicit endorsement with quantification
- Explicit endorsement without quantification
- Implicit endorsement
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Yvan Dutil at 23:13 PM on 22 May 2013Has the rate of surface warming changed? 16 years revisited
The key issue here as many of the linear decomposition is the potential hiden cross-talk between factor. Solar signal as at least some linear component in. Depending of the model, volcanic too. The same situation apply to any long period oscillation fitting used by skeptics.
Without physics statistical analysis are pretty limited tools. -
MikeArney3@aol.com at 22:33 PM on 22 May 2013Monckton Myth #11: Carbon Pricing Costs vs. Benefits
I guess this has been out there a while, but I think the sentence in the 3rd paragraph, "Here Monckton is implicitly assuming that the cost of preventing consequences will be less than or equal to the cost of adapting to consequences," should say, "greater than or equal". And I'd also take out the "implicitly", since he's pretty explicit about this (and very wrong, of course).
Thanks for all the great work you do on this site. I am very grateful for it.
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