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Tom Curtis at 07:35 AM on 24 September 2014Antarctica is gaining ice
jetfuel @276, from McMillan et al (2014):
"Here we use CryoSat-2 data acquired between November 2010 and September 2013 to produce the first altimeter-derived estimates of volume and mass change for the entire Antarctic ice sheet."
CryoSat 2 was launched in April 2010, and became officially operation in October 2010. The reason for the "overlap" in 2010 is simply that McMillan et al relied on earlier studies which extended into 2010. It is not clear, however, that those studies extended their data up to include Nov 2010 in any event, in which case there is no overlap.
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scaddenp at 07:34 AM on 24 September 2014Antarctica is gaining ice
Jetfuel, you seem to be implying that continuation of a predicted trend is somehow evidence for something new and different in Antarctica. Do you seriously believe that ice loss from the ice sheets has stopped? What is going to be your reaction to the next cryosat result? Do we get a retraction?
Again, it would help if you would actually state the point you are trying to make here. Why are you so hung up on Antarctica sea ice?
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jetfuel at 06:58 AM on 24 September 2014Antarctica is gaining ice
I disagree that 2013 is included, otherwise the quotes: "Between 2010 and 2013", "We use 3 years of Cryosat-2 radar al..",
and:
"are now 31% greater than over the period 2005–2010".
imply that 2010 gets counted twice, once in each dataset?
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michael sweet at 05:54 AM on 24 September 2014Antarctica is gaining ice
Jetfuel,
I read 2010-2013 as inclusive so that all the data up to last December is included. You cannot expect to have peer reviewed data about this winter available yet since the winter is not yet even over. A single snow event is weather. We are interested in the trend.
Of course scientists rapidly proposed explainations for the increase in ice: it had been predicted years ago. When events come to pass that were predicted long ago those papers are brought back and the proposed explainations look good. Predictions are not comparable to excuses.
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howardlee at 05:39 AM on 24 September 2014The Perplexing PETM
Timing and dating uncertaintly are a constant theme here. The apparently annually-layered ("varve") deposits reported on by Wright and Schaller are just the sorts of detailed record that should - eventually - resolve the controversy. Dating and correlation have constantly been improving in precision, but we are still dealing with vast timescales. My unscientific hunch is that the section reported by Wright and Schaller may turn out to be a short-lived blip within a much broader signal (like a fractal pattern - wiggles within wiggles). But you are right - more papers are sure to come on the PETM.
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jetfuel at 05:31 AM on 24 September 2014Antarctica is gaining ice
Again, 'between 2010 and 2013' excludes the last 21 months that includes the last 2 southern winters. Curiosity about the last 2 winters is not rhetoric.
Curiosity just uncovered that there was a 200 Gt snow event in East Antarctica in 2009. Things can change significantly in one year.
I acknowledge that there was more Ant. sea ice than now in the middle of the last century. I misspelled uncharted as unchartered. I don't even know what unchartered would mean in the context I used. 1966 seems about when actual winter max numbers were annually charted and that looks like about 22M sq km back then.
Breaking 20M for the first time since the mid seventies. Being quick to propose blaming this on reduced salinity and shifting wind patterns may be rhetoric. Those excuses were ready to go on the day the record from last year was broken.
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sidd at 04:48 AM on 24 September 2014The Perplexing PETM
Wright and Shaller reply to Stassen, Zeebe, Pearson in doi/10.1073/pnas.1321876111
Some of their retorts: that Zeebe's ocean model is inappropriate for shallow shelves, that drilling contamination is unlikely for various reasons, and that Stassen's argument assumes deeper water than was present at the site during the subject period. There is more, of course. I am personaly not yet convinced either way, but i eagerly anticipate more work.
sidd
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Tom Curtis at 04:02 AM on 24 September 2014The Wall Street Journal downplays global warming risks once again
jja, from David Archer at Real Climate:
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Paul D at 03:22 AM on 24 September 2014Upcoming MOOC makes sense of climate science denial
Good luck with the course.
Yet another great project from Skeptical Science! -
The Wall Street Journal downplays global warming risks once again
correction:
this comprehensive database indicates that global northern hemisphere peat north of 45' latitude contains 436 GT of Carbon. So the estimate given above is too high (for just Finnish peat carbon).
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The Wall Street Journal downplays global warming risks once again
The IPCC should produce a forward to the summary for policymakers stating a collective Mea Culpa to future human generations and a return of the Nobel prize as punishment for their fatal type I error aviodance bias.
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The Wall Street Journal downplays global warming risks once again
All,
it should also be noted here that the 100GT carbon estimate for RCP 8.5 is a middle range estimate with other studies showing an estimate as low as 25GT Carbon and as high as 500+ GT Carbon. There is over 1,600 Billion tonnes of Carbon in northern hemisphere permafrost.
In addition there is another 270-360 GT of Carbon in the sub-arctic peat, in FINLAND. http://hol.sagepub.com/content/12/1/69.short
This indicates an additional threat as the peat is already starting to burn in siberia and in the yukon territory. There is potentially more Carbon emissions potential from subarctic peat fires than there is from degrading permafrost.
I also doubt that the 55% atmospheric fraction will hold through 2100. The IPCC AR5 projects an increase to 70% for the RCP 8.5 by 2100. I expect, as with most projections from the IPCC RCP 8.5 scenario, that this is severely understated.
If the natural carbon sources above grow at significant rates, they wll overpass anthropogenic emissions by 2050 (assuming an agressive mitigation effort). -
Composer99 at 23:41 PM on 23 September 2014The Wall Street Journal downplays global warming risks once again
Ashton:
Pedantically, detailed discussions need not mean "met" in the conventional sense, in an era of long comment threads and email.
Substantially, "leading" climate scientists is a bit of weasel wording on Koonin's part. Although understandable given typical word limits (I assume the column was also published in the printed version of the Wall Street Journal) (*), the phrase could refer to climate scientists with loads of high-impact, well-cited papers published, or it could refer to S. Fred Singer, Richard Lindzen, and other contrarians with little to no recent publication and an extensive history of being wrong - or indeed, to any mish-mash of scientists Koonin personally felt were sufficiently notable to describe as "leading". This ambiguity does not resolve if we presume total sincerity on Koonin's part, since we have abundant evidence of contrarians genuinely treating contrarian scientists with extensive histories of being wrong as "leading" climate scientists.
With respect to your reference to Stern et al, I should remind you that Baron Stern, an economist, is usually referred to speaking within his domain of expertise, economics, in which case he is an expert, as is Professor Garnaut. For his part, Professor Flannery would be within his domain of expertise when discussing climate impacts on mammals (especially mammals in Australasia). I don't recall seeing Skeptical Science, or indeed any other science-based online source, rely on any of them for climate information outside their domains of expertise, although one could readily - and legitimately - include interesting or insightful things they have to say that illuminates the science. At any rate I do not see any justification for your apparent claim of tu quoque.
(*) For instance, I wouldn't want to spend substantial parts of an op-ed I wrote just naming scientists I spoke to.
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MA Rodger at 21:25 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
The zig-zagging that jwalsh continues to practice down this thread would be enough to provide an honest man with symptoms of psychiactric disorder. I am particularly impressed with his insistance that there is a significant 1200-year wobble in global climate. Thus @94 we are told:-
"That the climate has varied wildly in the past is not "out of left field". It is considered to be more established scientific fact than most IPCC statements. The Minoan, Roman, and Medieval warm periods occurred at roughly 1200 year intervals" and on this ground it is not silly to argue that "
While I assume this "established scientific fact" extends only to a significant wobble and not to a wild wobble, I was of the understanding that such "established scientific fact" would comprise some considerable evidential basis. Yet such a basis remains absent. jwalsh instead presents here argument after argument defending his thesis by asserting that the evidence which dis-establishes any 1200-year wobble is not admissible.
Marcott et al (2013), the place were such a wobble would surely feature is dismissed with an in-thread comment from Gavin Schmidt (although the comment was actually to do with MWP/modern comparisons, thus not entirely of relevance to 1200-year wobble detection).
We are emphatically assured @86 that there is other evidence but it is never advanced."Evidence of the Minoan, Roman, and Medieval warm periods from either historical records and other proxies? Hell yes."
Now, here's the thing. Both these quotes that together demonstrate a determined promotion by jwalsh of this alleged 1200-year wobble sit juxaposed to comment on Greenland ice core temperature reconstructions, things like Kobashi et al (2011) whose 4,000 temperature reconstruction from their Figure 1 is here. (Note the "Current Temperature Line" is the decadal temperature 2001-10. In a graph of the last 120-year reconstruction also within the full Figure 1, the paper puts the comparable annual temperature AD2010 at -27.3ºC.)
The reconstruction shows some pretty wild swings. But are there any wild 1200-year swings? Are there any significant 1200-year swings? Perhaps with his incomparable analytical skills jwalsh can help us out here, coz I see is a 4,000-year falling trend of 0.05ºC/century (which recent temperatures have already reversed within a single century) and a lot of wobbling but I do not see any wild or significant 1200-year wobble anywhere.
Moderator Response:[RH] This thread is turning into jwalsh's personal gishgallop. Let's try to bring it back on topic and take any splinter arguments to the proper threads. Also, one should note the full image in the Kobiashi 2011 paper where that graph comes from.
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scaddenp at 20:32 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Jwalsh "But if you change how much warming is assessed by CO2, it follows that the relative attribution of the warming is altered."
I am not following this logic at all. If you want to change the attribution from anthropogenic factors, you have to show one of the other forcings is significant. The size of the forcings is an input to models from measurement not an output. The strength of the temperature response in the models is indeed a function of the climate sensitivity - the feedbacks - but that doesnt have anything to do with attribution. Perhaps you need to explain (and source) your comments about "downshifting estimates" and "setting temperatures"? (or was that merely rhetoric?)The importance of OHC is that you cant attribute that increasing heat to a natural cycle - it has to be attributed to net forcings. It is not as noisy as surface temperature and so a good parameter to consider for attribution. Of course it isnt as relevant as surface temperature to us, but good for checking the basic science.
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Ashton at 20:15 PM on 23 September 2014The Wall Street Journal downplays global warming risks once again
You make the comment that Steven Koonin "claims to have engaged in “Detailed technical discussions during the past year with leading climate scientists,” but who is himself not a climate scientist." Two comments on that. First and least important, I can appreciate why you use the word claims but it does, at least to me, rather imply that Koonin might not actually have met with these "leading climate scientists". The comment that Koonin is not a climate scientist suggests he is not qualified to comment om matters climatic. If that really is what is suggested, one might ask why such import is placed on the utterings of Sir Nicholas Stern, Professor Ross Garnaut, Professor Tim Flannery none of whom are climate scientists. And Tom Curtis I wonder if Steven Koonin really doesn't understand the physics of the interactions between CO2 and incoming and out going radiation. It seems very unlikely.
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ubrew12 at 16:17 PM on 23 September 2014The Wall Street Journal downplays global warming risks once again
Tom Curtis@9: Koonan is no fool. He absolutely knows that vapor is a feedback, not a forcer, in these matters. He knows it, he knows it conflicts with the doubt he's trying to cast, and so he's leaving it out. He's leaving out 80% of the actual AGW effect of raised CO2 levels, because it would work against the lie he's selling his audience. His statement "human additions to carbon dioxide... shift the atmosphere... only 1%" is a lie to anyone with a smattering of Scientific knowledge... but it is legally correct. It's written by Koonin the lawyer, not Koonin the scientist. Hopefully he was paid at least 30 pieces of silver for betraying his training.
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PhilippeChantreau at 15:38 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Jwalsh you are showing deference for this individual by refering to him as "Lord" Monckton, a title that he has produced abundant effort to attach to his fictitious belonging to the House of Lords. The institution had to specifically address his claim, as is shown in my link. As for reading anything from him, the answer is no, that would be a complete waste of time.
And I don't find that you have appropriately addressed Tom Curtis points at 92 and 99 above. Far from it. You're long on assertions and rethoric, rather short on substance and references. The way you use references is itself quite questionable on several occasions. I understand more than I care to why you think how you think. It doesn't make it any more convincing.
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Composer99 at 15:20 PM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
jwalsh:
Cook et al 2013 are unambiguous as to why they chose to perform their review - that is, why they felt reporting on scientific consensus was necessary:
An accurate perception of the degree of scientific consensus is an essential element to public support for climate policy (Ding et al 2011). Communicating the scientific consensus also increases people's acceptance that climate change (CC) is happening (Lewandowsky et al 2012). Despite numerous indicators of a consensus, there is wide public perception that climate scientists disagree over the fundamental cause of global warming (GW; Leiserowitz et al 2012, Pew 2012).
and
Contributing to this "consensus gap" are campaigns designed to confuse the public about the level of agreement among climate scientists. In 1991, Western Fuels Association conducted a $510,000 campaign whose primary goal was to "reposition global warming as theory (not fact)". [It needs hardly be said that this is not the only expenditure by fossil fuel companies, associations, or affiliated "think tanks" to spread climate disinformation.] A key strategy involved constructing the impression of active scientific debate using dissenting scientists as spokesmen (Oreskes 2010). The situation is exacerbated by media treatment of the climate issue, where the normative practice of providing opposing sides with equal attention has allowed a vocal minority to have their views amplified (Boykoff and Boykoff 2004).
and
The narrative presented by some dissenters is that the scientific consensus is "on the point of collapse" (Oddie 2012) while "the number of scientific 'heretics' is growing with each passing year" (Allègre et al 2012). A systematic, comprehensive review of the literature provides quantitative evidence countering this assertion.
In short, if it weren't for a sustained misinformation campaign, aided and abetted by media emphasis on drama over accuracy, there would be no requirement for a study such as Cook et al 2013, just as there is no current requirement for a literature review showing, say, the level of expert consensus regarding quantum electrodynamics.
I should like to address your following comments:
The more discerning public is going to wonder similar things about this consensus claim. [...] Particularly when someone who thinks CO2 is causing 49.9% of warming is an explicit rejection, the lowest part of the scale, and a person at 50.1% is an explicit endorsement, the highest of the scale.
The "more discerning public" is going to read the IPCC reports and similar summary documents, and understand that the preponderance of evidence is what drives the expert consensus. I'm not surprised that you brought up the possibility of this hair-splittingly small distinction, which seems designed to obfuscate and muddy the waters rather than improve the paper's clarity.
There isn't any such thing as "the science" with respect to the complex and chaotic system that is our climate.
Unequivocally false. If you want to get down to brass tacks, you can sum up the basic fact of global warming with a single number:
0.6 W m-2
Everything else is commentary.
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Tom Curtis at 15:14 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
jwalsh @101:
"Taking an average as was done is of limited scientific utility. The criticism of picking one proxy over another is a valid one. I mentioned that as an issue straight away. Here's why it isn't that useful. They vary too much to do that. Say I give two people a tape measure to go measure an object, and one comes back and says it's 2.25 metres, and the second says 4.60 metres. If I actually need to know, would I take the average and proceed? No. I would know that one, or both measurements is flat-out wrong. The same is the case with data like the multi-proxies. You know one or more "must" be wrong"
Actually, with multiple proxies you do not know that any of them are wrong. What you know is that they are all regional proxies, and that regional temperatures differ from each other over time. You also know that the Global Mean Surface Temperature is the mean of all the regional temperatures across the globe.
So, the correct analogy is, suppose you send one person out to measure the height of a random individual in the city, and they tell you the height was 1.68 meters. Do you now know the average adult height? No. Suppose you send out eight people and they return with measured heights of 1.68, 1.82, 1.59, 1.76, 1.72, 1.64, 1.81, and 1.73. Do you now know that at least seven of them are wrong? Absolutely not. Do you now know that the average height is 1.719. No. But you do know that it is a much better estimate than the estimate from a single sample.
And if you take the mean of 73 samples (as with Marcott et al, without the bells and whistles), you know the result better still.
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jwalsh at 14:48 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Tom Curtis @99
1) I criticized you for using a regional proxy (GISP2) as though it were a global proxy. You implied your use was justified on the basis that tropical ice cores did not exist "they don't last so long". You now claim that you knew about them all along, which makes your original use of GISP2 simply dishonest.
The ice at closer to the equators is much, much rarer, and incidentally only exists at extreme altitudes. Similar criticisms to regional differences apply really. However, in signal quality the arctic and antarctic cores provide much less noisy data. I honestly can't look at your 6-core data and say there was, or was not a Minoan, Roman, or MWP. It just is simply too noisy. Anyone making that claim (and the authors did not) would find it difficult to defend. Not believing in the above periods of warmth is certainly an opinion. I don't share it, and I am hardly alone. Maybe there wasn't. So the reason for the clear Greenland curves is?
We could discuss the Marcott paper all day long. But the simple fact is, it is based on very low resolution data. It is going to be significantly "smoother" by method. Useful to discuss on a centennial scale, maybe, but not decadal. Whereas ALL of the GISP2 data is high resolution. And Greenland temperatures correlate well enough today to global. To endorse the Marcott paper as telling us useful information on the LIA and MWP is not something I, and G. Schmidt it would seem, would do, for those reasons. And how is Gavin Schmidt's thoughts on using the Marcott paper for that reason "out of context"? I can't think of a way for it to be more in context.
I criticized you for (in effect) taking the average of just one proxy as an indicator of changes in global mean surface temperature. You now respond by arguing that taking the average of eight such proxies is of dubious "scientific utility" and that it is a premise that is itself " itself is too absurd to bother" checking the maths.
Taking an average as was done is of limited scientific utility. The criticism of picking one proxy over another is a valid one. I mentioned that as an issue straight away. Here's why it isn't that useful. They vary too much to do that. Say I give two people a tape measure to go measure an object, and one comes back and says it's 2.25 metres, and the second says 4.60 metres. If I actually need to know, would I take the average and proceed? No. I would know that one, or both measurements is flat-out wrong. The same is the case with data like the multi-proxies. You know one or more "must" be wrong. So you dig in a little bit to try and figure out which. Or you throw the whole mess out and start over. The use of proxies like tree-rings and such and whether they are truly accurate enough is a point of contention. There is also the issue that they yield lower resolution data.
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Tom Curtis at 14:20 PM on 23 September 2014The Wall Street Journal downplays global warming risks once again
JoeT @4, I misread what Koonin wrote and withdraw my post @8, no because it is wrong, but because it is no relevant to his claim. (There really are deniers who argue the position I rebut there, which contributed to my confusion.)
The "natural" greenhouse effect is the difference between the upward IR radiation at the Earth's surface (390 W/m^2) and the upward IR radiation to space from the top of the atmosphere (240 W/m^2). Of that 150 W/m^2 difference 27 W/m^2 is from CO2, a further 13.5 W/m^2 is from other will mixed greenhouse gases including methane and ozone. The remaining 109.5 W/m^2 comes from water vapour (61.5 W/m^2) and clouds (46.5 W/m^2).
Those values are for circa 1980 conditions, and hence include a significant portion of anthropogenic forcing already. Hence the scare quotes on "natural".
Based on RCP scenarios, by mid century greenhouse radiative forcing from anthropogenic sources is expected to increase by about 1.5 W/m^2, which is about 1% of the "natural" total greenhouse effect. However, to obtain that figure, you need to only consider the change relative to current values. If you consider the total anthropogenic forcing since 1760, that figure approximately doubles, and if you consider the business as usual forcing by the end of the century, it tripples.
Further, Koonan is carefull to only consider the "direct" effect. The effect of water vapour and clouds are actually feedbacks on temperature. If you drop temperature, they will fall, whereas if you increase it they will rise. The result is that increasing CO2 also increases the WV and cloud greenhouse forcing (but also decreases, ie, make more negative, the cloud albedo forcing). The effect is so strong that for a doubling of CO2, a 3.7 W/m^2 direct change in the total greenhouse results in a further 16.3 W/m^2 increase in water vapour and cloud greenhouse effect in feedbacks.
So, by mid century the direct increase may be only 1 or 2%, but the total increase as a result of that direct increase will be a 5 - 10% increase in the total greenhouse effect.
So, Koonan is not incorrect per se, but his claim is framed to cultivate confusion - and he fails to provide the explanation that would dissipate that confusion.
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jwalsh at 14:06 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
PhilippeChantreau @97
I find it rather amsing that you'd adopt such snark toward Wikipedia but maintain deference for a buffoon like Monckton.
I am showing "deference" to Monckton by agreeing with a single thing the man said? I simply attributed the comment to him. I've read very little about, or by him, but happened to have done so recently enough. Should I? As for Wikipedia. Surely you know what it is. Wikipedia can be convenient for some things, but you almost always better check the references. The quality of information on it varies wildly. I usually avoid it for anything other than a starting point when possible. YMMV.
Perhaps you might point us to what you are precisely what you are implying but "relevant"? It seems you are yet again confusing sensitivity with attribution. Why do you continue to ignore the points the about OHC? Attribution is about sorting which cause created a particular change. Show us your evidence for another cause or stop trolling.
I've not once confused sensitivity with attribution. But if you change how much warming is assessed by CO2, it follows that the relative attribution of the warming is altered. I mostly ignored the points on OHC, because I am trying to stay on topic (attribution). OHC seems to me to be about where the heat is going, not what is causing it in the first place. Some are speculating issues with assumptions. And these "some" are many in the IPCC. Over-estimates of CO2 sensitivity could be one of those reasons. If there's nothing wrong with the attribution percentages, but only that the heat is all going into the ocean. That's fine, then the models have to be adjusted accordingly for the policy-critical estimates of surface temperatures. But I don't think there's complete agreement that that is indeed what we are seeing.
As for trolling. I am trying not to. If you don't understand the "why's" of those thinking somewhat differently, you stand little hope of convincing them, should you think that important.
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Tom Curtis at 13:47 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
jwalsh @95:
1) I criticized you for using a regional proxy (GISP2) as though it were a global proxy. You implied your use was justified on the basis that tropical ice cores did not exist "they don't last so long". You now claim that you knew about them all along, which makes your original use of GISP2 simply dishonest.
2) I do not discuss the MWP or LIA with reference to those ice cores. Rather, I discuss the absense of evidence of evidence for a RWP or Minoan WP, which you claimed exist on the basis of GISP2. Clearly from the ice core data they were not global events - and changing the topic does not make them so.
3) From Marcott et al, we learn:
"The results suggest that at longer periods, more variability is preserved, with essentially no variability preserved at periods shorter than 300 years, ~50% preserved at 1000-year periods, and nearly all of the variability preserved for periods longer than 2000 years (figs. S17 and S18)."
If approx 50% of variability is preserved at 1000-year periods, >50% of a 1,200 year cycle would show up in the reconstruction. It is, however, not there. No amount of quoting Gavin Schmidt out of context will change that.
4) I criticized you for (in effect) taking the average of just one proxy as an indicator of changes in global mean surface temperature. You now respond by arguing that taking the average of eight such proxies is of dubious "scientific utility" and that it is a premise that is itself " itself is too absurd to bother" checking the maths. That you so argue in order to maintain that the data from the once proxy is a reliable guide to the timing and direction of trends in GMST (if not their magnitude) shows how absurd your position is, and how completely lacking in scientific merit.
As an aside, I did not credit the graph to wikipedia regardless of your misrepresentation. I sourced from wikipedia, and acknowledged the source as is required by copyright law (as they wave their copyright on condition that you credit the source). However, I cited Robert Rhode, the author of the graph. That you ignore that to play your empty rhetorical games is only to be expected from a troll.
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scaddenp at 13:29 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
jwalsh - " Nothing to say about the IPCC experts on attribution downshifting estimates of future temperatures, setting aside temperatures at the mean or above from climate model projections as being unlikely? That would seem to be pretty relevant."
Perhaps you might point us to what you are precisely what you are implying but "relevant"? It seems you are yet again confusing sensitivity with attribution. Why do you continue to ignore the points the about OHC? Attribution is about sorting which cause created a particular change. Show us your evidence for another cause or stop trolling.
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jwalsh at 13:29 PM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
KR - Of course there's a lot of "selling" nonsense. Dangerously too much. It doesn't necessarily help to counter one with a different sales pitch. And I refuse to discuss "consensus without an object", whether it's by the Koch foundation or here! Any "consensus" needs to be clear about what exactly is being talked about. Not doing so is frustrating to people and will cause them to tune out. There is such thing as the charge on an electron. There isn't any such thing as "the science" with respect to the complex and chaotic system that is our climate.
I think educating the public on the actual science of AGW is a fine goal. I also think it's a largely irrelevant one. There wasn't any need to convince the public that the moon wasn't, in fact, made of cheese, to launch the Gemini and Apollo programs. You only needed to convince those funding the programs. And those people? They need more than vague information. They ask tough questions, and I wouldn't have it any other way. And yes, the money influence on politics is an enormous concern. There are indeed many industries and people not wild about their apple-carts being upset.
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PhilippeChantreau at 13:04 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Well, it seemed you did, kinda, or not, I'm not sure. I find it rather amsing that you'd adopt such snark toward Wikipedia but maintain deference for a buffoon like Monckton.
http://www.parliament.uk/business/news/2011/july/letter-to-viscount-monckton/
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PhilippeChantreau at 13:01 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Jwalsh, I note that you do not comment on any of Tom Curtis's arguments at #92, starting with the equatorial ice cores canard. I am unimpressed with your contribution so far.
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jwalsh at 12:59 PM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
Tom Curtis @92
It goes tiresome correcting the errors, lack of evidence and outright falsehoods on which you base your "expert opinion". Never-the-less, here are the results of six near equatorial ice cores from high altitudes:
Then don't? You made the choice to reply to me at all or not. But if it's your job to do so, there are worse things to be doing, and every job can get tiresome at times. The six ice-cores mentioned come from Lonnie Thompson's paper. Interestingly, it's referenced as often by those wishing to show evidence of a LIA and MWP as often as it is to try to show a lack of both. Most that have looked at that the data have deemed it too noisy to say anything about either, which allows people to interpret it however they like. It's also trotted out as corroboration of a particular set of reconstructions, that seem to be moderated if mentioned, or critiqued in any way. I mentioned that I didn't want to delve too deeply into paleo reconstructions for the same reason. The existence or not of the LIA/WMP is a point of contention. Due to inconvenience, there are many trying to suggest that they were only European, or Northern Hemisphere, or didn't happen at all... etc. etc. There is evidence that both were global. And there is evidence that it wasn't. Part of the problem is that most studying it over the years seem to do so in the north. The NCDC of NOAA thinks the Greenland, Antarctic and other Arctic cores suggets both well enough. I wish we truly did have a great source of data spanning the globe and time with high precision.
As for Marcott 2013? I think Gavin Schmidt summed it up well.
http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/
"This is not the paper you should be interested in to discuss the details of medieval/modern differences. Given the resolution and smoothing implied by the age model uncertainties, you are only going to get an approximation."
And the vaunted academic source for all things climate "Wikipedia" (does Wm. Connolly still babysit it like a hawk on methamphetamines?) .... Hmmm. Not sure what the scientific utility is of averaging multi-proxy studies together. It gives rise to interesting features though. Such as it being cooler in 2004 than it was 8,000 years ago. I'd check the math myself, but the premise itself is too absurd to bother.
However, back to attribution. Nothing to say about the IPCC experts on attribution downshifting estimates of future temperatures, setting aside temperatures at the mean or above from climate model projections as being unlikely? That would seem to be pretty relevant.
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pbdoc at 12:06 PM on 23 September 2014Newcomers, Start Here
Hey there, great website, thanks for all the great information.
A friend of mine is concerned about the earths magnetic fields and how they are affecting the climate. He sent me this, can someone comfortable with the climate science comment on this and if it something that has been studied or overlooked? Thanks.
http://phys.org/news/2014-05-earth-magnetic-field-important-climate.html
Moderator Response:[PS] Fixed link. The link only talks about changes in the "climate" of the upper atmosphere which, while important for many applications, isnt exactly what most people would think of in terms of climate change.
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scaddenp at 11:48 AM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I believe the only goal of the consensus project was to counter the myth "there is no consensus". The importance of this is not for the science but because the consensus position is the only rational basis for making policy whether it is climate or chewing gum. If new data changes the consensus, then policy can be changed as well.
On the question of attribution, the data we possess supports the position that warming since 1970 is 100% anthropogenic, not 10%, 50% or 70%. If you are going to argue for another source of change, then present the data to support that position.
This is particularly so for OHC. Unless you also wish to challenge the consensus of the conservation of energy, you cant talk about unforced natural cycles changing OHC beyond minor wiggles from ocean/atmosphere exchange. I cant see how any amount of dickering about the uncertainties in the forcings can change the position that the warming is anthropogenic.
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Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
jwalsh - There has indeed been a lot of "selling" on this topic; various and sundry attempting to convince the public that the science is unsettled, uncertain, that we don't know enough to make reasonable policy decisions. "Selling" by the "skeptics", following Frank Luntz's advice to falsely convince the public that no consensus exists, solely to prevent action. Political rhetoric, in other words.
Papers like Cook et al and discussions of the 'Consensus Project' are simply efforts to correct that misinformation, to bring public perception closer to reality. Efforts, I'll note, that you seem to object to strongly - IMO a position more of politics than reality.
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jwalsh at 11:10 AM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Composer99 @355
(*) Recall that the scientific consensus - the degree of expert agreement - about AGW is a stand-in for the preponderance of evidence gathered regarding AGW, as outlined in (to pick a not-so-random-example) the IPCC reports.
One of the goals of the "Consensus Project" is to convince the public of the existence of a consensus. That this doesn't seem to be a goal of climate scientists themselves much, I would deem important too, but I don't believe the correct way to go about doing that is to be imprecise over just what the consensus is supposedly about.
Why? Because the natural inclination of people is to be skeptical and to sniff out "spin". They go their whole lives with people trying to sell them something or another. A famous example of this is an advertising claim made by a sugarless chewing-gum manufacturer. They made the claim that "Sugarless gum is recommended by four out of five dentists for their patients who chew gum." The more perceptive amongst the populace noted that, dentists should probably stick to maintaining and fixing people's teeth. And.. "Have you considered the benefit of NOT pestering dentists with ridiculous questions?" But people also noted that "for their patients who chew gum" was an important qualifier. And they also sensibly wondered "What does the fifth dentist recommend? Gum with sugar?" The answer of course was some variation of "Get out of my office.", or "That's a stupid question." or "Chewing sugarless gum is a habit with no discernible benefit one way or another to your teeth." The company made use of this by making a funny campaign that had the fifth dentist shouting "NO!" as a squirrel bit him on the nuts.
The more discerning public is going to wonder similar things about this consensus claim. The "fifth dentist here" either takes no position on their patients gum-chewing, and is in fact, closer to the 4/5. They'll take note of the logical weirdness of deciding that someone who acknowledges that greenhouse gases are a thing that can cause warning is "endorsing" anything meaningful. Particularly when someone who thinks CO2 is causing 49.9% of warming is an explicit rejection, the lowest part of the scale, and a person at 50.1% is an explicit endorsement, the highest of the scale. Fortunately, the vast majority of scientists wouldn't ever sign up to such a ludicrously precise number, and at best would put it as a range, if pressed, or not quantify at all. The "implicit endorsements" might place it at 10%, 100%, or "potato". We're not really sure. I think the question for any such consensus to be sold to the public needs to be clear, concise, and asked directly.
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michael sweet at 11:06 AM on 23 September 2014Antarctica is gaining ice
Jetfuel:
I Googled "Antarctic ice loss" and found This link from June 2014. It says:
"Between 2010 and 2013, West Antarctica, East Antarctica, and the Antarctic Peninsula changed in mass by −134 ± 27, −3 ± 36, and −23 ± 18 Gt yr−1, respectively. In West Antarctica, signals of imbalance are present in areas that were poorly surveyed by past missions, contributing additional losses that bring altimeter observations closer to estimates based on other geodetic techniques. However, the average rate of ice thinning in West Antarctica has also continued to rise, and mass losses from this sector are now 31% greater than over the period 2005–2010"
Your suggestion that ice loss in the Antarctic is not increasing is incorrect. Perhaps if you Googled better you would be more up to date on your data. At least it is not doubling every five years.
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Tom Curtis at 10:26 AM on 23 September 2014CO2 effect is saturated
rational being @284, the Earth's surface emits IR radiation upward at approximately 390 W/m^2. Absent IR absorbing molecules in the atmosphere, that IR radiation would radiate to space, making the total IR radiation to space from the Earth 390 W/m^2.
As it happens, some of that IR radiation is trapped by IR absorptive molecules, which then radiate based on their temperature. On average, IR radiation from water vapour radiates from an altitude of (very approximately) 4 km. At that altitude, temperatures are on average 26 K cooler than at the surface due to the lapse rate, so the IR radiation to space from water vapour is at (very approximately) 267 W/m^2. On average IR radiates to space from 10 km altitude, and hence from a temperature of 213 K. Consequently its IR radiation is at (very approximately) 116 W/m^2.
Combined across all factors, including the IR radiation from cloud tops, the IR radiation from the surface through the atmospheric window, and the differences in altitudes in radiation at different latitudes (along with the differences in surface temperatures), the total IR radiation to space averages at 240 W/m^2. That is, it very closely matches the incoming solar radiation averaged across the Earth's surface. Absent the IR active gases, however, it would radiate at the much higher level of the Earth's surface. That, of course, would create an energy imbalance leading to the rapid cooling of the Earth's surface until outgoing IR radiation matched incoming solar radiation again, with the Earth's average surface temperature near 255 K.
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scaddenp at 09:38 AM on 23 September 2014Antarctica is gaining ice
Jetfuel, it remains completely unclear quite point you are trying to make.
Is it?
1/ Antarctica seaice is increasing, therefore Antarctic is getting colder
- not true as you have been shown. The paradox with seaice increase it that it happens while temperatures warm. Read the provided links/papers for why. Salinity decrease is only part of the story.2/ Antarctic sea-ice increase "makes up" for Arctic sea ice loss.
- Nope, as pointed out above, the increase is only 1/6 of the climatological effect from seaice loss in arctic.
3/?? What are else?
I would have say that it is statement of mighty hope to believe that ice sheet loss has decreased significantly since 2012. Cryosat-2 was measuring record loss rates in 2010-2013. Glacier movement rates were increasing in southern summer of 2013-2014. What do think has suddenly changed to give you that hope?
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Tom Curtis at 09:34 AM on 23 September 2014The Wall Street Journal downplays global warming risks once again
JoeT @4, CO2 contributes only 1 or 2% to the downward IR radiation at the surface (back radiation). It contributes around 20% to the reduction in outgoing IR radiation to space relative to the upward IR radiation from the surface. Another 75% or so comes from water vapour and clouds, and constitutes the water vapour feedback which many deniers claim does not exist. It is the reduction in upward which constitutes the greenhouse effect, and the reduction in upward radiation that controls the energy balance equation that determines long term temperature trends. The back radiation is important for weather, but in principle its effects can be replaced by changes in the rate of convection. (There is, of course, no convection to space so that is not true of the outgoing IR radiation.)
So, at base Koonan's claim is based on a simple misunderstanding that shows he completely misunderstands the nature of the greenhouse effect, or that he is completely dishonest, or that he is simply parroting memes provided by others without understanding what the mean and what they are related to. The science really is settled on this one, so there is no fourth option.
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Tom Curtis at 09:27 AM on 23 September 2014The Wall Street Journal downplays global warming risks once again
ubrew12 @12, jja is correct. Carrying the point through, however, only 55% of the emmissions, or 26 ppmv, are retained in the atmosphere. That corresponds to an additional 0.25 C warming on top of that from a 450 ppmv concentration (which seems inevitable from directly anthropogenic sources alone). That 0.25 C is based on the ECS, and for a short term response may be half of that.
A better way to look at it, however, is that it is estimated that we can emit a cumulative trillion tonnes of Carbon and still have a reasonable chance of avoiding dangerous climate change. We have already emitted 580 billion tonnes, so 100 GtC is 24% of our remaining allowance.
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Tom Curtis at 09:14 AM on 23 September 2014Antarctica is gaining ice
jetfuel @270, the failure to acknowledge clear errors (such as your claim that "the Antarctic is well into unchartered territory in increased area covered by sea ice") shows your purpose in debate is not understanding, but purely rhetorical. Further, referring to data without providing a clear web address or link suggests you are hiding behind your interpretation of the data rather than relying on it.
More directly, the question is not the level of salinity, but the change in level of salinity. From your wording, your NASA site only shows the former. Here is the later, from Zhang (2006):
As you conveniently point out, the trend in Antarctic sea ice is 40 years long. Therefore the 1979-2004 data should provide the clue as to the cause of the increase in sea ice extent, for the sea ice extent was increasing over that period. We therefore notice that it is not due to changes in temperature, which was increasing over that period (panel e). Salinity, however, was decreasing over much of the Antarctic waters (panel d). Further, NASA accepts that data, and agrees that the decline in salinity is part of the explanation of increased ice extent.
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The Wall Street Journal downplays global warming risks once again
ubrew12 @ 3
2.12 GT of Carbon is equal to 1ppmv of CO2 so 100GT of carbon from melting permafrost is equal to 47ppmv of CO2.
This means that the most agressive mitigation strategy through 2050, in attempting to stabilize at 450ppmv will significantly overshoot.
the reality is that permafrost carbon moves approximately 55% into the atmosphere in the form of CO2. So even this analysis is severely understated. It looks like even the most agressive mitigation strategy won't stabilize below 550ppm. This means that we have a significant job ahead of us removing CO2 from the atmosphere in an attempt to restabilize at 400ppmv. -
jetfuel at 08:36 AM on 23 September 2014Antarctica is gaining ice
Any data out there that shows Antarctic ice mass changes since Sept 2012 cannot be found by me. I understand that the -100 GT/yr number is floated around but there is no data to support this trend over the last 2 years. It is as though 2009 and 2010 data are currently on replay.
Per TomCurtis@268, Antarctic sea ice area is on the rise for almost 40 years as a general trend. With Nasa data showing ocean salinity as average surrounding Antarctica, as opposed to low salinity at the Amazon delta or Black sea, that salt dillution argument is weak as to why sea ice is unprecedented since the early 70's.
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Tom Curtis at 08:35 AM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Russ R @350:
1) When I was young I had a biopsy on a lump on my knee which was poorly executed and kept me on crutches for several weeks (and provided a far larger and more gruesome scar than when my leg was ripped open by a wire while sliding down a hillock on cemment bags). Being on crutches for that period was a significant adverse impact. The more so because it caused me to favour one foot over the other (without my knowing) which has lead me to have ingrown toenails late in life. It was not by any stretch of the imagination catastrophic. Neither, for that matter were my three broken bones, said accident with the wire, or the various times I have bounced motorbikes of my knee as I hit the pavement (including the occassion that laid the skin back to reveal the patella. "Significant adverse consequences" does not mean "catastrophic", whatever your rhetorical needs to distort the language.
Of course, significant adverse consequences for a society are much larger than significant adverse consequences for an individual, but so also is the level of harm that is needed for the events to be called catastrophic.
Further, my clause (c) explicitly gave a probability indicator. The "significant adverse consequences" are likely, which allows that there is a real possibility that they will not happen, and even a very remote possibility that there will be net benefits. So at most your distortion should be Potentially Catastrophic AGW, which indeed I believe it to be although I do not think that is the consensus position.
2) Michael Sweet's comment about your marking yourself as a denier with the use of the term CAGW is entirely correct. So are his citations, although I would have preffered just the IPCC myself.
3) Bray and Von Storch (2010) asked a sample of climate scientists:
"22. How convinced are you that climate change poses a very serious and dangerous threat to humanity?"
In the responses, 78.92% were more than half responded 5 or higher on a 7 point scale where 1 was "not at all convinced" and 7 was "very much convinced". If you want to take that as the consensus level on clause (c), I have no problem. I do note, however, that "a very serious and dangerous threat to humanity" is a far larger level of harm than "cause significant adverse consequences". I further note that my clause (c) says only that the level of harm is likely, so that strictly even those who are 50/50 on the proposition (response 4, 10.81%) or even 43/57 (response level 3, 4.054%) should be considered part of the consensus on clause (3). That would lift the consensus level to 93.784%, ie, within error of 97%. The actual consensus on (c) is likely to lie in the 90% region, IMO (based on Bray and von Storch).
Regardless, while Cook et al do not investigate opinions on future impacts, it has been investigated in the "consensus literature" contrary to your claim. And in that investigation, the proportion of climate scientists who think there is no risk of "a very serious and dangerous threat to humanity" from AGW is only 1.162%
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ubrew12 at 08:21 AM on 23 September 2014The Wall Street Journal downplays global warming risks once again
JoeT@4: There are people on these comments way more qualified to answer you than me, but just looking at the temperature effect, if 0ppm CO2 to 280ppm raises temperature by 60F (the greenhouse effect), then going up to 560ppm (a doubling) will only bring it up another 5F, or about 8%. I'm sure the way he's doing it is in Watts/sq in or something but who cares. It's severely disingenous. He's claiming that the basis for comparison of the effect of AGW is with a planet with no greenhouse effect (also known as a ball of ice). Well, sure, compared to such a planet, the effect of AGW is in the noise. And compared to the Sun, Earth is cool. So what? The Real point is: does that 5 F matter to us mere humans. Koonin excepted, apparently, yes it does.
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jwalsh at 08:00 AM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
KR @89
1950-1960 is not when anthropogenic contributions become detectable in the climate record, but rather when they become dominant over natural forcings.
This would be a distinction without a difference for the purposes.
GISP2 is a local record, not a global one, recording temps at a single point on the Greenland ice cap. There is no evidence that I am aware of for 1200 year cycles, incidentally - that claim of yours appears to have materialized out of left field.
That the climate has varied wildly in the past is not "out of left field". It is considered to be more established scientific fact than most IPCC statements. The Minoan, Roman, and Medieval warm periods occurred at roughly 1200 year intervals. I acknowledge that the GISP2 is a local record. It is not, however, the only record. And a person would need to describe some proposed mechanism of extreme arctic warming and cooling cycles independent of the rest of planet earth to speculate that it was local. Could there be such a thing? I am not sure. I would be curious to hear one.
Negative anthropogenic forcings have a fairly high uncertainty - but the best estimate is for a climate sensitivity around 3C/doubling of CO2. Claiming that they are small and that correspondingly ECS is low (as you appear to) is a cherry-pick of but one low-likelyhood end of the PDF, and that isn't justified by anything other than wishful thinking.
Considering that there is strong observational evidence to support an ECS estimate of below 3, I am not alone. In fact, I suspect that a FAR greater percentage than 3% of the IPCC themselves would agree there. One need only pick through the IPCC expert reviewer comments to easily demonstrate a lack of clear agreement. I think that the PDF cobbled together from the 10.5 figure is getting an inordinate amount of attention. It would be similar to deciding that any particular PDF for climate sensitivity itself was the "correct" one. As observed my many, AR5 seemed to weight model methods of determination of ECS over observational ones with little justification. This would be, incidentally, in contrast to AR4 with no well-documented reasoning.
Temps have been running below (averaged) model projections for ~15 years - a statistically insignificant time period, while remaining in the 2-sigma model range. That means there has been no invalidation of the models to date.
If you'd like to discuss what is a statistically valid time period, that would be an interesting discussion. Certainly a great deal of ink has been made over the statistically much more "valid" 18 year period of 1980-1998. Do we really need to wait just a few years to consider an 18, 20, or 25 year trend? The IPCC thinks not. How many people have drawn trend lines over CRUT4 data or UAH satellite data? However, if 15 years is too short of a time period to consider making model adjustments, those actually doing so, such as those running them, are being hasty. And the IPCC themselves would be being "hasty" in using short term temperature data to alter their own 20-year temperature projections well below that of the model outputs. And they did exactly that in AR5.
It's worth noting here, that I don't think the IPCC attribution is "way off". Just minorly so. And for the record, I don't rule out climate sensitivity of "4" either, or indeed attribution of AGW of 120%. How would I know? As I said, greater effort would probably spent worrying about convincing the much smaller fraction of scientists who put it well below 50%.
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Tom Curtis at 07:50 AM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
michael sweet @91, that is not a fair statement of the consensus. There are a significant core of climate scientists who do think that the IPCC, in general underplays the problem. There are also a substantial majority that think it gets it about right, and a large number who think it overestimates the problem by a small degree. Some of those (such as James Annan, and John Nielson-Gammon) are clearly very competent scientists who are following the science as best they understand it, as indeed are those on the other side of the coin. Further, some IPCC projections are clearly high including global temperature increase, which runs about 15% below projections even after accounting for ENSO. For other observations, IPCC projections are low (as with reduction of Acrtic Sea Ice extent, and sea level rise).
My problem with jwalsh is not that he thinks the IPCC has overestimated the problem, and more specifically the attribution level. His position is a consensus position. My problem is that he does so based on either no, or clearly misrepresented evidence. If you are going to disagree with the IPCC, you should do so scientifically, which clearly he does not.
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Tom Curtis at 07:38 AM on 23 September 2014The 97% v the 3% – just how much global warming are humans causing?
jwalsh @86:
"Yes, there's a tricky limitation with ice cores. The ones at the equator don't last nearly as long. I didn't say they were a perfect match to NH temps (or global). Evidence that the Greenland temperature swings were localized for some reason? None provided. Evidence of the Minoan, Roman, and Medieval warm periods from either historical records and other proxies? Hell yes. But sure, might not be as extreme in swing. Do you have a good explanation for the approximately 1200 year cycles?"
It goes tiresome correcting the errors, lack of evidence and outright falsehoods on which you base your "expert opinion". Never-the-less, here are the results of six near equatorial ice cores from high altitudes:
Here are three of the tropical or subtropical icecores along with three polar icecores:
And here the equivalent ice core (in blue, dO18) from Mount Kilimanjaro, which at 3 degrees, 3.5 minutes south, I think counts as being "at the equator":
You will notice that only Sajama has, what might be considered to be, your 1,200 year cycles. You will further notice the distinct hockey stick in the 6 ice core composite.
Further, I refer you again to the Marcott et al (2013) reconstruction of holocene temperatures, as displayed above along with eight temperature proxies and their arithmetic mean as constructed by Robert Rohde for wikipedia:
Again, the Roman Warm Period and the Minoan Warm Period, not to mention the 1,200 year cycles are only present in GISP2, and is distinctly not present in the global reconstructions.
The RWP and MWP are distinctly North Atlantic phenomenon, and have significant impact over European temperatures. That they do not have any discernible impact on global temperatures is a spear in the side of any theory that modulation of North Atlantic Temperatures is a significant, let alone a major cause of variance in global temperatures.
So:
"Evidence that the Greenland temperature swings were localized for some reason? None provided."
Evidence the sky is blue? None provided either, and none needed because it is assumed to be well known by anyone well informed on the topic as you claim to be.
"Evidence of the Minoan, Roman, and Medieval warm periods from either historical records and other proxies? Hell yes."
But exclusively restricted to NA (and immediately neigbouring land) proxies showing beyond doubt that they are regional, not global variations in temperature. As we are discussing impacts on global temperatures, your introduction of a known regional temperature proxy with poor correlation with other regional temperature proxies counts as a red herring at best - and is either proof that you are not well informed on the topic, or that you are intent on deception (if you are indeed well informed).
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CO2 effect is saturated
rational being - I'm not entirely certain what your question is. CO2 at the top of the atmosphere radiates energy into space in the IR bands, with an effective emission altitude generally defined as where 50% or more of the emission escapes without absorption. That altitude is determined by the total amount of IR absorbing gases above that point in the atmosphere, and is rather directly related to the partial pressure of GHGs.
As CO2 levels increase, that effective emission altitude increases. Given the lapse rate, an increase in altitude means a decrease in temperature, hence a reduction in the IR energy radiated, an imbalance at the top of the atmosphere. That imbalance will persist as energy accumulates on the surface, warming the entire atmospheric column including the CO2 at the effective radiating altitude, until the energy radiated equals the energy incoming from the sun.
Summary: Increased GHGs -> increased radiating altitude thus colder radiating gases -> less energy leaves -> climate warms -> upper atmosphere warms as a result -> amount radiated equals amount received.
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rational being at 07:03 AM on 23 September 2014CO2 effect is saturated
CO2 and similar assymetric species are necessary in order to radiate IR into space, for the same reason that they absorb IR.
IR frequencies are those of the bond-stretching modes and couple to the EM field via molecular dipoles (and molecular rotation to conserve angular momentum).
Suppose the upper atmosphere contained only N2 and O2. These molecules' bond motions cannot couple to the EM field [to 1st order] so cannot radiate IR. The heat would be trapped until the temperature rose enough to allow electron modes to radiate.
But there is CO2. And if the partial pressure of the CO2 is increased, that should provide more opportunities for the upper atmosphere to radiate, and so cool the upper atmosphere.
We already know that vertical heat transport in the lower atmosphere is dominated by convection [the IR "greenhouse effect is saturated there].
So doesn't that mean that extra CO2 in the upper atmosphere is an advantage to shedding IR into space?
I suspect that human changes to land use will turn out to be the dominant anthopogenic contribution to climate change.
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JoeT at 06:52 AM on 23 September 2014The Wall Street Journal downplays global warming risks once again
In his article Koonin states,
"For example, human additions to carbon dioxide in the atmosphere by the middle of the 21st century are expected to directly shift the atmosphere's natural greenhouse effect by only 1% to 2%."
Anyone know what he is referring to when he says one to two percent? -
Composer99 at 05:59 AM on 23 September 2014Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I believe, Russ R, that you should probably attend more to the goalpost-sized log in your own eye before getting so exercised about the mote in that of the current POTUS. (*)
I mean, your initial line of attack last week was that there were serious problems with Cook et al 2013, using a source that alleged fraud on the part of the Cook et al author team.
This week, without the slightest peep of acknowledgement that last week's criticisms were bogus, we're on to how President Obama is being misleading. That's practically a textbook example of moving the goalposts:
Person A: Cook et al is wrong [baldly stated or carefully insinuated] because reasons.
Person B: Those reasons are all rubbish. [Explanation demolishes reasons presented by Person A.]
Person A: Well, what about Obama's tweet, then?
(*) Recall that the scientific consensus - the degree of expert agreement - about AGW is a stand-in for the preponderance of evidence gathered regarding AGW, as outlined in (to pick a not-so-random-example) the IPCC reports.
So President Obama, at least, has a leg to stand on when he Tweets "climate change is real, man-made and dangerous", even if he is off the mark in referring to "ninety-seven percent of scientists" and providing a hyperlink to the Reuters article describing Cook et al 2013.
Moderator Response:[PS] Just a friendly reminder that political discussions are forbidden by the comments policy. Please dont let this discussion veer into politics.
Also, [RH] Russ is officially off this topic due to excessive repetition. You can find him on the It's not bad myth thread.
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