Arguments
Recent Comments
Prev 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 Next
Comments 44701 to 44750:
-
KK Tung at 10:30 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to Robert Way at post 139: I agree with you. Not knowing what the true AMO is, all these definitions of the AMO index are ad hoc. Enfield's definition of the AMO index involves linear detrending of the N. Atlantic sea surface temperature (SST). Many on this thread worried that some nonlinear part of the trend may still remain in the AMO index thus defined. Many felt strongly that the Trenberth and Shea definition of the AMO index should be used. This index is the N. Atlantic mean SST minus the global mean SST. The assumption of those who thought this definition is more appropriate is that this way the nonlinear anthropogenic trend can be removed. I discussed this issue in part 2 of my post: The N. Atlantic mean SST trend is smaller than the global SST trend, and so this subtraction takes out too much. So right there we know there is an error. Technically the presence of a trend in the regression index also creates a problem of collinearity. An approach that we have taken is to use different methods and hope that the results are consistent. The wavelet method may have its own problems, but these problems are orthogonal to the problem of the MLR as no detrending is involved. Alternatively, we could do the MLR using different definitions of the AMO index. As Robert Way put it, we know that there could be some possible defect with any ad hoc definition we can come up with, but hopefully the true answer may lie in between. Even better if the error bars are small. I will give you a summary of this sensitivity calculation soon.
-
KK Tung at 08:54 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to KR at post 140 and 142: I did report the result of MLR using Trenberth and Shea's AMO index. The 50-year anthropogenic trend is 0.1 C per decade. There was a problem with collinearity because that index has a negative trend, and I discussed why it has such a negative trend. I will try to put these sensitivity calculations together, along with a discussion of Ting et al 2009 paper, in a separate post.
I had replied to your question on the Anderson et al paper. As far as I am concerned that issue was settled.
-
Mal Adapted at 07:40 AM on 8 June 2013Imbers et al. Test Human-Caused Global Warming Detection
John Nielson-Gammon gave a talk at last year's AGU meeting on Scientific Meta-Literacy. His key point:
But there’s an important lesson here about how we decide which scientific statements to believe and which ones not to believe. Those of us who are trained scientists but who do not have enough personal literacy to independently evaluate a particular statement do not throw up our hands in despair. Instead, we evaluate the source and the context.
We scientists rely upon a hierarchy of reliability. We know that a talking head is less reliable than a press release. We know that a press release is less reliable than a paper. We know that an ordinary peer-reviewed paper is less reliable than a review article. And so on, all the way up to a National Academy report. If we’re equipped with knowledge of this hierarchy of reliability, we can generally do a good job navigating through an unfamiliar field, even if we have very little prior technical knowledge in that field.
Well, the typical member of the public has very little retained technical knowledge about just about everything. I claim that it’s an impossible task to raise the level of climate literacy in the general public to the point where most can tell that the statement about the ice age is wrong, let alone whether the statement about Sandy is wrong. And what about all the other fields in which they need to be literate as well?
The solution to this problem is not scientific literacy, but what I call scientific meta-literacy. Forget that dream about enabling the public to independently evaluate scientific claims on their merits – that’s just not going to happen. Instead, enable the public to distinguish between reliable and unreliable sources of scientific information.
Skepticism is all very well, but it's important to understand that it takes work to become an expert, and if you're not willing to do the work, you have little choice but to trust the ones who have. A genuine skeptic recognizes and respects expertise. Otherwise, he risks falling prey to the Dunning-Kruger effect.
-
william5331 at 06:10 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
"Humlum had just disproved the conservation of mass" Who says scientists don't have a sense of humor. Priceless.
-
KR at 05:54 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Dr. Tung - My apologies, I linked to entirely the wrong paper in this comment: I meant to refer to the Ting et al 2009 discussion on PCA separation of internal variability and anthropogenic contributions.
-
Bob Loblaw at 05:29 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
The stratospheric cooling associated with increasing greenhouse gases is not a new idea. It shows up in 1-D radiative-convective modeling work in the 1960s. Two such early studies are:
-
John Hartz at 05:29 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal has recused himself from positng on SkS.
-
Tom Dayton at 05:27 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordontonal, you seem to be unaware of... well, the entirety of climatology. So you consistently have made comments that are entirely off base (e.g., wrong, not even wrong), as you try to apply your general knowledge of science and philosophy. I suggest you start by learning the history of the science behind our knowledge of global warming. Then learn more about the fundamental physics of the greenhouse gas effect--physics that are known from actual experiments in the lab and observations in the field. Physics knowledge that was established without any thought to humans increasing global warming.
-
John Hartz at 05:21 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal:
Please note that posting comments here at SkS is a privilege, not a right. This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Moderating this site is a tiresome chore, particularly when commentators repeatedly submit offensive, off-topic posts or intentionally misleading comments and graphics or simply make things up. We really appreciate people's cooperation in abiding by the Comments Policy, which is largely responsible for the quality of this site.
Finally, please understand that moderation policies are not open for discussion. If you find yourself incapable of abiding by these common set of rules that everyone else observes, then a change of venues is in the offing.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter, as no further warnings shall be given.
-
John Hartz at 05:16 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal:
Please note that posting comments here at SkS is a privilege, not a right. This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Moderating this site is a tiresome chore, particularly when commentators repeatedly submit offensive or off-topic posts. We really appreciate people's cooperation in abiding by the Comments Policy, which is largely responsible for the quality of this site.
Finally, please understand that moderation policies are not open for discussion. If you find yourself incapable of abiding by these common set of rules that everyone else observes, then a change of venues is in the offing.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
-
Dikran Marsupial at 04:53 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
chordotonal, "sloganeering" is clearly defined in the comments policy. Please read them.
I for one am not going to bother responding to your posts while you continue to use phrases such as
"That is a real bread and butter concept of science that is being attacked in service of what amounts to religious belief."
If you want to discuss the science, that is fine, but drop the rhetoric, nobody here is interested.Moderator Response:[JH] Chordotonal's subsequent post was sloganeering and was therefore deleted.
-
DSL at 04:43 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Again, you build a strawman in the form of an alleged attack by SkS posters on correlation in general. No. If you're going to claim correlation = causation, as Lu did, you'd better damned well start talking about the physical mechanism in a methodologically sound way. Lu's method was unsound.
-
Dikran Marsupial at 04:42 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
Bob Loblaw - very apposite, unlike my favourite maths joke:
Q. Why did the mathematician call his dog Cauchy?
A. Because he left a residue at every pole!
-
Bob Loblaw at 04:35 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
With all this discussion of the problems caused by Humlum et al's analysis that differentiates the data first, I am reminded of a math joke told to me years ago by a mathematician friend. (Yes, I know. "math joke" is an oxymoron. Don't ask me to tell you the one about Noah and the snakes.)
Two mathematicians are in a bar, arguing about the general math knowledge of the masses. They end up deciding to settle the issue by seeing if the waitress can answer a math question. While mathematician A is in the bathroom, mathematician B corners the waitress and tells her that when his friend asks her a question, she should answer "one half X squared". A little later, when the waitress returns to the table, A asks her "what is the integral of X?". She answers as instructed, and mathematician A sheepishly pays off the bet and admits that B was right. As the waitress walks away, she is heard to mutter "pair of idiots. It's one-half X squared, plus a constant".
[I'm not sure how much of the joke is a dig at mathematicians who forget some of the basics (the constant), or a dig that mathematicians can only find jobs working as a waitress in a bar.]
But, back to the issue at hand - differentiation will take any constant term and turn it into zero. But to take the flux data and turn in back into a change in storage you have to integrate. And when you integrate, you are in deep, deep trouble if you forget the constant, which is what Humlum et al appear to have done. If you can't figure out what the constant is, then you can't figure out the numerical value of the integration.
Details. Details.
-
John Hartz at 04:25 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal: You most recent post was sloganeering and was therefore deleted. Please read the Comments Policy and adhere to it.
-
Dikran Marsupial at 04:11 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
KR testing the sensitivity of the analysis to the choice of AMO definition would indeed be a good thing, however they would all be susceptible to the problem of contamination with anthropogenic and natural forcings, and hence the resulting attribution will still be at best questionable.
-
KR at 03:45 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
robert way - While there are many ways to calculate the AMO, I would disagree about Anderson et al 2012 being ad hoc; they are using PCA to estimate the anthro versus natural variation components; they have numeric support for their position. And they agree with the Trenberth and Shea 2006 method.
Regardless - Any comparison of Dr. Tungs technique against different AMO estimations would provide a sensitivity analysis for those variations in AMO definition. Dr. Tung has not performed such a check - and until/unless he does, I do not feel his conclusions stand given the various counterexamples of colinearity contamination discussed on these threads.
-
Micawber at 02:59 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
I thought the BEST group of physicists had proved once and for all that all global warming in last 250 years can be accounted for by volcanism and the log of CO2 concentration.
Rohde, R., Muller, R. A., Jacobsen, R., Muller, E., Perlmutter, S., Rosenfeld, A., Wurtele, J., Groom, D. and Wickham, C.: A new estimate of the average earth surface land temperature spanning 1753 to 2011, Geoinfor Geostat: An Overview, 1, 1, 7pp, doi: 10.4172/gigs.1000101, 2012.
This is consistent with the physics. The greenhouse gas is active in the upper stratosphere/troposphere boundary. To solar radiation Earth looks like a bubble. This bubble traps the heat. It is dependent on CO2 rather than water vapour that does not reach so high. Rohde et al., (2012) is consistent with this and explains all the temperature changes observed. What goes on inside the bubble affects that surface. Most of the surface is saltwater.
There is s similar boundary layer in the upper ocean that traps heat. According to Levitus et al., (2012) ocean heat accounts for 93% of anthropogenic global warming.
Levitus, S., Antonov, J. I., Boyer, T. P., Baranova, O. K., Garcia, H. E., Locarnini, R. A., Mishonov, A. V., Reagan, J. R., Seidov, D., Yarosh, E. S. and Zweng, M. M.: World ocean heat content and thermostatic sea level change (0–2000 m), 1955–2010, Geophys. Res. Lett, 39, L10603, 5pp, doi: 10.1029/2012GL051106, 2012.
Data from oceans is sparse at best with 1 degree lat and long coverage averaged over upper 100m only available since 1990s. What is needed is far better data on the 93% heat and rather less statistics on the 7%.
Unfortunately this requires going to sea and making actual measurements. It is timeseries of near-surface temperature and salinity data that holds the key. These are not available from satellites. Computer models are only as good as the field verification data. There are huge tracts of ocean for which data is lacking including the Pacific and the Arctic.
In my opinion it is time for a concerted effort to go to sea and get the data. It can only confirm what Rohde et al., (2012) showed - CO2 concentration is the principal driver of global warming; and confirm Levitus et al., that 93% of that is in the oceans. -
robert way at 02:58 AM on 8 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
"KR I would strongly suggest theTrenberth Shea 2006 methodology, supported by Anderson et al 2012, as one detrending methodology worth considering."
KR,
I disagree. All these ad-hoc methods of calculating the AMO are not rationalized and if you read the article I listed before you will see that these variants of the AMO ALL struggle when it comes to deciphering the proper signal. Personally I use two versions and compare the results of each. One is the detrended first component of North Atlantic SSTs and the other is the Van Oldenborgh et al, 2009. They're both wrong but I believe that reality lies between the two. Once again reading that previous study I linked to here:
http://link.springer.com/content/pdf/10.1007%2Fs00382-013-1669-0.pdf
Should be read by everyone while discussing this issue. -
Falkenherz at 01:55 AM on 8 June 2013CO2 increase is natural, not human-caused
Thanks for the answers and sorry for the double-post, no idea how that happened.
Moderator Response:[Dikran Marsupial] no problem, easily fixed.
-
DSL at 01:51 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal, Lu has been riding this pony for a while. He's received published feedback on it. He's ignored it (look at the links at the bottom of the main article). When does it get real?
-
DSL at 01:48 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
reality, I'll be happy to discuss "climategate" with you on the appropriate thread. I'm professionally interested in what you learned from "climategate."
-
Chordotonal at 01:30 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
"The problem all along has been his lack of providing the necessary mechanics to support that fitting. Should that be the basic requirement for publication?"
If you are saying he needs a good apriori case yes I agree. If you are saying that he does not have one, yes I agree with that also. But we ought not get too precious about publication. So we are saying he has a good one-shot correlation but he doesn't have a good apriori case. So its just a matter of making a start on an hypothesis that is likely going to wind up failing for lack of convergent evidence. We ought not be treating him as some sort of heretic, since this is how you go about proving things.
Moderator Response:[JH] You are skating on the thin ice of sloganeering and excessive repitition -- both of which are banned by the SkS Comments Policy. Please read the Comments Policy and adhere to it. Thank you.
-
DSL at 01:25 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal, where did this become about Lu's basic use of curve-fitting. The problem all along has been his lack of providing the necessary mechanics to support that fitting. Should that be the basic requirement for publication? If so, Willis Eschenbach just smiled. The number of pedal strokes I used to get to work this morning was exactly the same as the number of strokes used by Paris Hilton to comb her hair this morning. I say the two are causally related. It has to do with the . . . ummm . . . gravitational resonance from the friction in my bottom bracket. The frequency of the resonance matches Hilton's brain structure, causing the repetitive motion at just the right time. What? She combs her hair every morning, even when I'm not riding my bike? Not listening! Not listening! I'll be publishing soon in Journal of Auras and Dweomers.
In a world where rapid global warming is not an issue, does Lu repeat and publish the analysis? SkS is also about the communication of climate science, and Lu's garbage looks like gold to the paid misinformers of the general public. If you perform poor science and then try to get it published, knowing that it will be used to confuse the general democracy . . . what's up with that? -
Dikran Marsupial at 01:14 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
(-snip-).
A word of advice, you have now posted argumentative messages on several threads. This is usually a sign of drive-by trolling, becuase very few people would have the time and energy to engage in meaningful discussions of so many scientific topics in one go. If I were you I would (a) restrict myself to one topic at a time and (b) pay attention to what is actually written in the responses to your posts. Fail to do so and I suspect that you will find yourself recieving even more attention from the moderators.
Moderator Response:[DB] Response to snipped off-topic and sloganeering snipped.
-
Chordotonal at 01:11 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
(-snip-). Falsification is okay but it ought to be convergent. And falsification is not nearly as important as verification. What we want is convergent verification. I don't think that Lu is going to get convergent verification. I suspect that its just a matter of luck. But to pretend that finding a correlation for an hypothesis is not even a valid part of the process appears "a bit rich" as it were.
Moderator Response:[DB] Off-topic snipped.
-
DSL at 01:07 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
What you have, Chordotonal, is a scientist presenting a hypothesis and the proceeding to support that hypothesis by picking and choosing whatever evidence seems to support the hypothesis (don't look too closely) and ignoring whatever doesn't support it. Need to get rid of CO2 as a GHG? Ok, go all Angstrom and use the saturation argument. Ignore the fact that it is completely unsupported in the literature.
I imagine it passed peer review because it was reviewed by Lu's peers -- people who were not experts in the field and who had little idea of the mess that Lu was creating out of the existing literature. -
Chordotonal at 01:06 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
(-snip-). I don't think Lu 's hypothesis will pan out by the way. But the process by which you prove things like this is going to involve curve fitting and correlation. Its very strange to be clziming otherwise.
Moderator Response:[DB] Off-topic snipped.
-
Dikran Marsupial at 00:55 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Chordotonal wrote "With Lu there is nothing wrong with the evidence so far."
Far from it, as discussed in the article itself. If you want to engage in the discussion and support Lu's work then identify a specific flaw in the article and discuss it.
I suggest you read the comments policy, particular the item about sloganeering. If you make posts that make arguments that are not backed up by evidence they are likely to be deleted.
(-snip-).
Moderator Response:[DB] Response to off-topic snipped.
-
Chordotonal at 00:46 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
"Extraordinary claims, counter to large collections of existing work, require extraordinary evidence -"
This phrase is from Carl Sagan. (-snip-). Its actually a plea for a handicap. And to make such a plea would indicate that ones hypothesis needs a handicap. (-snip-). (-snip-).
Moderator Response:[DB] Off-topic and sloganeering snipped.
-
Chordotonal at 00:42 AM on 8 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Its a thing both odd and very ambitious to be using "Curve fitting" as a pejorative in science. At least this fellow found a curve that fit.
-
Dikran Marsupial at 00:18 AM on 8 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
CBDunkerson wrote "How could this Humlum paper have gotten through peer review?"
Peer review can only be expected to be a basic sanity check, and sometimes the reviewers selected may not be sufficiently expert to spot the flaws. The more times a paper is submitted to a journal, the more likely it is that some journal will accept it eventually. Peer review has always been susceptible to the occasional failure, but science has adopted a good way of dealing with bad papers, which is to simply ignore them. The problem comes when papers are written that have impact on the general public that don't have the background to see the errors.
In many fields bad papers draw little attention from anyone, it is the public focus on climatology that means that the bad papers get exposed. If "skeptics" didn't draw so much attention to them in the blogsphere/press, the bad climate papers would be simply ignored as well.
-
DSL at 23:57 PM on 7 June 2013It's soot
Beyond that, though, what reality apparently ignores or is ignorant of are the following two realities:
1. Global ice mass loss is in no way fundamental evidence ("trump card") for the theory of anthropogenic global warming. It is evidence for the proposition that ice melts when conditions are physically conducive to melting. If you want physical evidence of a warming planet, look at ocean heat content and the expected and observed shifts in general circulation.2. CMIP3 modelling severely underestimated Arctic sea ice loss (by 60-70 years). If the reason for that underestimation is BC (and I'm not saying it is), then removing the BC signal would probably leave CMIP3 modelers (some of those tens of thousands of "warmist scientists") in a much improved position.
-
KR at 23:56 PM on 7 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Why is the AMO used in this MLR analysis still detrended linearly?
Please suggest a better way if you know of any. Note that to minimize collinearity in the MLR, the AMO index preferrably should not contain a trend, but you are encouraged to suggest different ways for detrending.
I would strongly suggest theTrenberth Shea 2006 methodology, supported by Anderson et al 2012, as one detrending methodology worth considering.
At the very least, I would suggest repeating your analysis with these and/or with a simple quadratic detrending - and determining the sensitivity of your analysis (and conclusions) to the choice of detrending method. That issue is, I believe, the core of these discussions, and a question well worth answering.
-
KR at 23:45 PM on 7 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
John000 - I would suggest looking at the Climate Sensitivity thread, where the various uncertainties are discussed.
Estimates for climate sensitivity come from model results, from observations over the instrumental period, from responses to volcanic eruptions/aerosols, and paleo observations over the last few ice age cycles. Not just models! The climate sensitivity values used in such discussions are, in general, the synthesis of many lines of evidence, which is one of the reasons why extrema estimates such as Lu's tend to raise eyebrows.
Extraordinary claims, counter to large collections of existing work, require extraordinary evidence - Lu has not supplied the same, nor answered earlier criticisms of his work.
-
John0001 at 23:40 PM on 7 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
IanC#40: Thank you, Ian. You made good points.
-
gws at 22:09 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
@1 Esop
Some positive: There was a good article/interview in Bergens Tidene last Wednesday (in Norwegian) with Bruno Latour, this year's Holbergsprisen vinner. He also made some excellent points about denying climate change in the print version, which I could not find online.
-
CBDunkerson at 22:05 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
Mark, while the publication of your analysis is a wonderful response, I have to look at this Humlum paper and others like it with a growing sense of dread. It seems to me as if 'alternative realities' are creeping into science just as they have into politics, journalism, law, economics, and other formerly respectable fields.
How could this Humlum paper have gotten through peer review? Why would Global and Planetary Change publish it? How can the universities that employee the authors not be embarrassed to be associated with this?
I always thought that science was largely resistant to falsification because bad results would inevitably be uncovered and damage the credibility of all involved. Yet we seem to be seeing a lot of clearly wrong analysis getting published and no particular fallout when it is uncovered. Indeed, I doubt the denialsphere will stop praising Humlum in light of your findings... rather they will continue to accept his as valid and reject yours... creating two different views of reality. A situation I view with horror.
Obviously, there has always been fringe 'science' and from time to time it has gotten published... but am I wrong in believing that things have changed in that we are now seeing it actively celebrated and promoted even in the face of proof to the contrary? I fear a future in which publishing bad science can be a path to greater carreer success. Rupert Murdoch's News Corporation routinely puts out false propaganda in the guise of journalims... and is beloved for it. Radical ideologues routinely get appointed to the highest courts despite rulings bearing no resemblance to legal precedent or justice. Raving lunatics frequently get elected to high political office. The whole world is suffering from the guidance of economists who promoted austerity during a massive global recession.
If this kind of madness takes hold in the sciences we are truly doomed.
-
Lanfear at 21:39 PM on 7 June 2013It's soot
Reality's writing here got me thinking of what would be the implications if the following claim would be true:
"Arctic melt---and that of glaciers and the permafrost is caused not by CO2, but by black carbon[ soot] from the burning of forests and other biomass in China, India, Indonesia, other Asian countries and Brazil"
My thinking is that the BC needs to be pretty well mixed into the upper layer of the troposphere in order to travel all the way to the arctic, and hence, it should be visible also in the Himalayas, even in the uppermost areas.
So is it legitime to assume that in order for BC to be the dominant effect, and especially considering that the some of the listed countries surround the Himalayas, the effect should also be visible in upper levels of the said region. Ie. the topmost glaciers should also be darker and melting?
-
EliRabett at 21:01 PM on 7 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Dave@23 UV effets is a handwave at the change in the proportion of UV radiation in the solar spectrum within the solar cycle. The increased UV below 306 nm then does increased photochemistry. Lu does little more than handwave
-
MA Rodger at 19:21 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
reality @21.
I would reinforce the message @24 by saying that you must be very careful with your language. You say " ...there is no acceleration in the rate of change of CO2." I don't know if the meaning is what you intended but it is not true. The rate of change of CO2 is not accelerating. Nor is it flat as you assert it is. It is increasing but roughly linearly, ie CO2 levels are accelerating at roughly a constant rate.
A further argument for 100% of the increase being human in origin is the constant ratio between rises in atmospheric CO2 and emitted CO2 . Over the last 50 years that ratio has remained wobbling between 40% & 50% . And this ratio remains totally unaffected by the addition of the emissions from "China's huge growth in coal-fired power stations and cars etc in recent years" which may feature large in press reports but whose impacts are best analysed numerically.
And long may that ratio stay 40-50%. If it starts dropping it will likely be due to feedback CO2 emissions from the melting cryosphere or warming oceans.
-
MarkR at 19:02 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
#21 reality
The top graph is just some functions I made up to demonstrate what one part of their approach does. I found the visual impact helpful.
The bottom one shows the components of CO2 rise and you can see that both human emissions and atmospheric CO2 accelerate. Over this time period the rates are extremely similar and if you directly compare atmospheric CO2 with human emissions then the correlation coefficient is about 0.99.
By differentiating it you cut the cooefficient drastically, to around 0.4. This is because the short term variability masks much of it on short timescales, which was the point I tried to make with the top graphs!
-
Dikran Marsupial at 18:46 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
reality@21 Humlums argument is based on a (already well known) correlation between the rate of increase in atmospheric CO2 and temperature. The rise in atmospheric CO2 is cause by the average rate of increase being positive. Correllations however are insensitive to the average value of the signals, so the correllation between the rate of increase in atmospheric CO2 and temperature can not explain the increase itself.
We know that the rise is caused by human emissions. Atmospheric concentrations are rising more slowly than cumulative human emissions, so consevation of mass means that the natural environment must be a net carbon sink, taking more CO2 out of the atmosphere each year than it puts in. There is a natural contribution, but it is strongly negative.
The reason that there is little rate of increase while anthropogenic emissions have been rising approximately exponentially, is that rising atmospheric CO2 concentrations mean that the natural net carbon sink has been strengtheneing as well. This gives rise to the constant so called "airborne fraction". If you are happy with differential equations, there is a worked example in the paper I wrote which is referenced in my SkS article here.
-
reality at 18:45 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
Esop...
What no attention is paid to by many warmist scientists, is the role of black carbon in the melting of the Arctic sea ice.
Scientists, including Drew Shindell of NASA, Jacobson and Ramanthan amongst many others [ non-sceptics], met with Congress to tell them the results of research that showed that ~50% of the Arctic melt---and that of glaciers and the permafrost is caused not by CO2, but by black carbon[ soot] from the burning of forests and other biomass in China, India, Indonesia, other Asian countries and Brazil---and a smaller amount from the burning of diesel fuel.
Warmist scientists cite the Arctic melt as the trump card that 'proves' the earth is warming alarmingly, but they almost never mention the black carbon problem at all.
Yet Drew shindell said that there's no point in only going after CO2 mitigation, since black carbon can be relatively easily mitigated with almost immediate effect.
It would seem that scientists who don't mention BC, and pretend that the only impact on the melting in the Arctic is rising CO2 emissions ,are deceiving the world---not helping at all, when some clamor from them would help politicians to do what's necessary--especially as the Arctic melt has a catastrophic feedback in the lowering of albedo, by the formation of dark water where once there was ice.
Moderator Response:[Dikran Marsupial] Discussion of black carbon is off-topic, this article is concerned with the cause of the increase in atmospheric CO2. If you want to discuss black carbon, please find a more appropriate thread.
-
gws at 18:40 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
@21
"What you object to in ..."
Please read the article again. You have just created a strawman.
"If the CO2 in the atmosphere ..."
You are beating the strawman, 1. by ignoring the discussion and information given by others before your entry, 2. by ignoring the overwhelming evidence. Pretty much what Humlum et al. did ...
-
reality at 17:46 PM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
What you object to in Humlum's graphs seems to be that the constant nature of the increase in CO2---same gradient---when differentiated produces a flat line, showing that there is no acceleration in the rate of change of CO2.
If the CO2 in the atmosphere was caused by human emissions, with little or no natural contribution, surely the curve would have a changing gradient [no longer linear and constant] depicting the increases in emissions eg with China's huge growth in coal-fired power stations and cars etc in recent years.
-
KK Tung at 15:54 PM on 7 June 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
In reply to MA Rodger at post 135: Four of us, Dikran Marsupial, Dumb Scientist, Jiansong Zhou and I, have spent hours making tens of thousands of Monte Carlo simulations trying to answer the question: if the anthropogenic signal is highly nonlinear (quadratic or fifth order polynomial), will the linear detrending of the AMO index used in MLR necessarily leave us with a wrong linear anthropogenic trend? The correct summary of our efforts so far ( I have not gotten to post 134 yet, but will shortly) should be, in my humble opinion, that we have not found such an example (although we should always be on guard for such a possibility). This is despite some of the extreme examples constructed and discussed here, and undoubtedly more such examples have been tried but not shown here ( I know we have tried many). A thank you is in order to the three of you.
I therefore disagree with your summary:
In this thread, it has been demonstrated by Dikran Marsupial & also Dumb Scientist that the MLR analysis is sensitive to an underlying quadratic trend if a sinusoidal signal used in the MLR is linearly detrended when the trend it contains is quadratic.
In all logical and semi-realistic cases, the MLR so far has yielded the right answer within its 95% confidence internal, although in some cases, the "right" answer is useless because the error bars are too large. We think we understand why in some of these hypothetical cases the error bars are so large. Fortunately the error bars are usefully smaller for the real data.
Given this situation, here is the question:-
Why is the AMO used in this MLR analysis still detrended linearly?
Please suggest a better way if you know of any. Note that to minimize collinearity in the MLR, the AMO index preferrably should not contain a trend, but you are encouraged to suggest different ways for detrending.
-
Doug8919 at 14:08 PM on 7 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Calling the Science Daily piece an 'article' is generous - it's just a reprint of the press release, which is all Science Daily does. Of course, this didn't stop it being cited as supporting the research by The Australian's consistently abysmal Cut & Pate column.
-
IanC at 12:27 PM on 7 June 2013Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
Hi John,
Indeed there is still a large uncertainty in the equilibrium climate sensitivity (ECS), primarily due to cloud feedback, which dominates the uncertainty: the range of cloud feedback in 12 models is almost as large as the spread in ECS itself; I think this is unlikely to converge until we get to the point where clouds can be modelled somewhat explicitely.
Even though the spread among model is large, the important thing is that even if you pick out the best case scenario for each feedback aong the models in Dufresne and Bony 2008 (i.e. model 1 for surface albedo and water vapour+lapse rate, model 2 for cloud feedback, you will still get a warming that is very close to 2 degrees. In other words, there is very strong evidence that warming will not be less then a degree.
Climate model is really just a way for us to quantify our physical understanding. Skeptics often point to the uncertainty as a problem, but I think the right way to look at the spread is that we can implement our current knowledge in 12 different ways, and under no circumstances is the warming neglible.
Yes, most of the time ECS is used instead of splitting it up to alpha and beta, I think the reason is that you can't in reality increase the temperature without the water vapour feedback, so making the distinction between the two is pointless for most applications.
-
MarkR at 11:24 AM on 7 June 2013New study by Skeptical Science author finds 100% of atmospheric CO2 rise is man-made
#15 chris : thanks for the mention, it appears to have dropped out due to a minor technical problem, I have contacted the publisher about returning the reference to the bibliography.
#6 HJones : Figure 1 is only an example of what happens with a linear trend and cycles. Two more points are 1) The green line is cycles, which would be the 'natural' case. The blue line is what would happen with a constant flux from humans. 2) the real human emissions (and contribution to atmospheric CO2) have accelerated, which was why a correlation was easier to pick out.
#18 Jonas : differentiating a linear function returns the gradient, e.g. dy/dx when y=5x returns 5. That's why my first graph has the blue line as a constant value of 1.
Prev 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 Next
