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Comments 60351 to 60400:

60351. dana1981 at 13:36 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Shakun et al. do not comment on the relative importance of different factors. As noted in the Climate Sensitivity section in the above post, they do not comment on the size of radiative forcings other than greenhouse gases. I suspect they would not differ significantly from the estimates in Hansen and Sato (2011) - Figure 5 above.
60352. Michael Whittemore at 13:35 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Tom Curtis @54 Just to add, thanks for your posts, it explained what happened much more clearly, I will also read the Clark et al. paper.
60353. danielc at 13:34 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Michael: Careful - copyright violation does get snooped... don't be blatant. @Tom, I will check it out, but the air is getting pretty thin for me - I am much more a geologist and jack-of-all-trades than a bona fide climate scientist/modeler. I specialize in tectonics and structural geology, with a strong interest in linked fields (of which this is one, to be sure)... but getting into the bones and guts of these models is very hard for me to do with confidence...
60354. Michael Whittemore at 13:26 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       One of the perks of being enrolled in uni, I seem to be able to look at most papers for free :) You want me to email you the paper in pdf?
60355. Tom Curtis at 13:07 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Michael Whittemore @53, the paper is behind a paywall for me, so I cannot asses Shakun et al's claims on the subject. However, that seems unlikely to me. It is likely that there were changes in albedo concurrent with, and possibly preceding, the initial increase in CO2 levels. Based on the data from Clark et al quoted above, GHG "forcing" represented approx 40% of the total "forcings", and hence temperatures would have increased by about 2.4 C without the CO2 and methane feedback (based on Shakun et al's estimate of the temperature difference between LGM and the present). That estimate ignores the relative significance of different factors in triggering the transition which I am not able to assess. Perhaps Dana or somebody else who has read the paper can fill in with more details of Shakun et al's estimate of the relative importance of different factors in triggering the transition.
60356. Michael Whittemore at 12:42 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Tom Curtis @52 Thanks for the explanation. As the paper says that 93% of the warming happened after the CO2 rise, is it fair to say that without the rise in CO2, there would had only been about 7% of the warming taking place?
60357. Phil L at 12:35 PM on 11 April 2012
       2012 SkS Weekly Digest #14
       KR and Sphaerica - Carbon sequestration in wood products obviously isn't the final solution, but it can be a significant factor in mitigation efforts. Arguing that sequestration for the lifetime of wood frame houses is useless because it is shorter than thousands of years seems akin to saying that Canada may as well not make any effort because of China's emissions. An important point is the avoidance of fossil fuels in production of steel or concrete buildings, as pointed out by the IPCC.
60358. Tom Curtis at 12:30 PM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Michael Whittemore @51, from the article above I do not see where Shakun et al claim 93% of warming was caused by CO2. The article does say that " According to the Shakun et al. data, ... 93% of the global warming followed the CO2 increase." However, just because something follows something else does not mean it was caused by that thing. I suspect that Shakun et al believe the warming was caused by a combination of CO2, albedo changes due to the loss of continental ice sheets, methane, albedo changes due to change in vegetation, and changes in dust levels in the atmosphere among other factors. Of these, albedo changes are the largest factor, followed by CO2 and methane in that order. With respect to g, the formula is f = 1/(1-g), where f is the feedback response and g is the "gain", so named by analogy with electronic circuits. Again, the gain is not just the CO2 response, but the partial response to any warming. Any such response results in further feedbacks and hence further warming. So long as the partial response is less than 1, the total response approaches a limit equal to f (which is what we are interested in and can measure). For any study, g = 1 - 1/f, and f is approximately equal to the climate sensitivity for a doubling of CO2. Hence, base on the article above, f is probably about 2.5 and g is 0.6 for fast feedbacks; and f is probably about 6, and g 0.833 with slow feedbacks included (using Hansen's method of determination). The important thing here is not the numbers, because we cannot measure g directly. It is the understanding that the response to an initial warming does not happen all at once, but incrementally with initial responses causing further responses, and so on; and the understanding that this process is self damping provided that each incremental response is less than the temperature increase that caused that response.
60359. Michael Whittemore at 11:27 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Has a study been done on the amount of CO2 that was initially released and the amount of feedback temperature increase should have happened. Shakun et al. 2012 says 93% of the warming was caused by the CO2, could that value be confirmed with are |g^x| < |g^y| understanding of feedback's?
60360. Tom Curtis at 11:27 AM on 11 April 2012
       Human CO2 is a tiny % of CO2 emissions
       wsugaimd, The Earth has five short term reservoirs of CO2, and two long term reservoirs. The short term reservoirs are, in order of size: 1) The deep ocean; 2) The soil; 3) The surface ocean; 4) The atmosphere; and 5) The biosphere. Flows between these reservoirs is very large, and very rapid. The result is that soil, surface ocean, atmosphere and biosphere maintain equilibrium on a time scale of around a year, while the deep ocean maintains equilibrium on time scales of a century or so. These reservoirs are shown in this diagram from wikipedia (note, black ink indicates storage, blue ink indicates fluxes): Because fluxes between these reservoirs are rapid, equilibrium is maintained between them. Consequently the normal fluxes between these reservoirs cannot increase the total CO2 (or chemical derivatives such as cellulose) in the aggregate of the reservoirs. What is more, because equilibrium is maintained, except for circumstances which shift the equilibrium they will not result in changes in any particular reservoir. For example, increased aridity will result in less carbon being stored in soils and the biosphere. As a result, more carbon will be stored in the atmosphere and ocean. If it is a short term change in aridity, it will not effect the deep ocean, but if it is a change that lasts for a century or so, the excess CO2 (and derivatives) in the atmosphere and surface ocean will be depleted partially to re-establish equilbrium with the deep ocean. Similarly an increase in sea surface temperatures will result in diminished CO2 storage in the surface ocean, resulting in more CO2 being stored in the atmosphere, soils and biosphere (from the CO2 fertilization effect among other effects). Such changes in SST are responsible for much of the small changes in CO2 concentration prior to 1750 and visible in the graph @224 above. They are also responsible for the strong correlation between ENSO and the short term fluctuations in CO2 concentration as observed by modern instruments. In addition to the short term reservoirs, there are two long term reservoirs. They are sedimentary rocks, particularly lime stones but including coals and other fossil fuels, and the Earth's mantle. Transfer between these reservoirs and the short term reservoirs is normally very slow. This occurs by the formation of sedimentary rocks, which are then subducted to the mantle, which returns the CO2 to the surface through volcanos. Currently the rate at which volcanos return CO2 to the surface is about 1/100th of the rate at which humans emit CO2. In effect, humans have increased the transfer from the long term reservoirs to the short term reservoirs by a hundred fold. Because the short term reservoirs are in equilibrium, it is far more logical to consider that transfer as the cause of increase in CO2 storage which has been measured in all five of the surface reservoirs than to assume that the cause is a transfer from one surface reservoir to another (as you are doing). Indeed, it is only possible to consider the high relative flux from the biosphere to the atmosphere through respiration as the cause of the increase in atmospheric CO2 if you firmly ignore two points: a) The equally large flux from the atmosphere to the biosphere by photosynthesis; and b) The fact that the atmospheric CO2 has been effectively stable for 10 thousand years even in the presence of the large flux from biosphere to atmosphere, which as remained essentially unchanged.
60361. danielc at 11:13 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Tom, agreed for the most part... Tilt is a major part of the story, but tilt + precession for a given ellipticity will augment and potentially enhance (a lot!) the differences... NH in the last several million years is inherently more sensitive for a number of reasons: 1) land surrounding polar/arctic region, 2) More land (i.e. more material with lower heat capacity), 3) more land - again (more area for plant growth), 4) more limited and confined ocean circulation paths (both surface and deep water). We can see that sensitivity in the present day in many ways: the difference in absolute value for CO2 measurements compared between north and south, the difference in seasonal variability in CO2, temperatures, water vapor, and so forth between north (large variability) and south (small variability)... Now, as to whether spring insolation vs summer insolation makes that huge of a difference (i.e. does it matter if it comes in Sept. - Dec. or Oct. - Jan) in the SH, I honestly do not know... what does seem clear that at least on first look, the response in the NH drives the bus, and the triggering that happens, happens because of what goes on up North, rather than down South. One way that we sort of knew this already is that Antarctica has been ice-locked/ice-covered since 33 m.y.b.p. (or so), and yet recent style glaciations that involve significant coverage of the NH have been ongoing only since the last 10 million years (sort of) and really less than 3.5 mybp ... (I know there are some lines of evidence and working hypotheses that contest this, suggesting Oligocene glaciation in the NH, but that work is still in progress as far as I know). Point being that the paper that sparked this discussion is saying almost the same thing as the much larger scale geological record: the Southern Hemisphere appears to respond quite faithfully to global insolation/milankovitch/weathering carbon cycle systems, but is not a sensitive trigger like the NH appears to be.
60362. KR at 10:45 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Sphaerica - I've often found that following the Google Scholar "All N versions" link points to at least one PDF copy of the paper, possibly on the authors university site. Not in all cases, but in a great many...
60363. Tom Curtis at 10:10 AM on 11 April 2012
       Human CO2 is a tiny % of CO2 emissions
       Posted by wsugaimd here, and moved because of topic:

       "Thanks for the info. Sorry for posting on a wrong? link. First time here so I'll learn...I'm coming from a biology background and I'm not sure of the argument that its the C02 driving the temp. Heres why... Its estimated that there are 560 billion tons of biomass, not including bacteria or oceanic bacteriophage/viruses which far out weigh all prokaryotic and eukaryotic life forms. There are 10 million viruses in a drop of seawater. What I'm trying to say is that as temp rises, life forms increase metabolism, i.e., release more C02. Even plants exhale C02 at night. And I believe the C02 exhaled by all biomass on earth has far more impact than the few "pennies" our cars put out. Is my CO2 different from a frogs? I think not."

60364. dana1981 at 10:09 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       wsu @46 - please also see the rebuttal to the myth CO2 increase is natural, not human-caused'. You are incorrect on this issue.
60365. Tom Curtis at 10:03 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       danielc @35, actually we are disagreeing. If you look closely at the graph, you will see that at the onset of the last glacial/interglacial transition, there was increased insolation in the NH (top two panels) from March to August. In contrast, in the SH (bottom panel) the increased insolation is from August to December, corresponding to the SH spring. There is reduced SH insolation in January through to March, corresponding to the SH summer and autumn. Clearly my post was inaccurate as well. However, it is a mistake to think that NH and SH insolation effects are equal either by month or by respective season. Changes in the eccentricity of Earth's elliptical orbit will effect both hemispheres in the same way at the same time. Changes in axial tilt (obliquity) will have opposite effects on the different hemispheres, with the synchronization with the elliptical orbit determining whether it moderates of reinforces the NH summer insolation. The combined result is the complex pattern you see in the figure at 34. The reason the NH effects dominate in transitions between glacial and interglacial is because if snowfall extends further north in the SH is simply falls in the ocean and melts, thus preventing the formation of ice sheets.
60366. wsugaimd at 09:50 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       (snip)
       Moderator Response: TC: Of topic comment moved to the appropriate thread. wsugaimd, you are new here so I am extending you the courtesy of moving your comment rather than simply deleting it. Future of topic comments will simply be deleted. There is an extensive list of "skeptical" objections to the theory of AGW on the side bar. Using it, or the search function will allow you to find discussion of almost any "skeptical" talking point on AGW so that you can post under the correct topic. If you are interested in genuine discussion, I strongly suggest you do the readers the courtesy of posting where they can see the AGW side of the argument immediately without having to do the search themselves. You may also be interested in reading the other side of the argument yourself. If you cannot find the appropriate topic, ask where it is in the digest of the week thread. Regardless of whether you wish to do our readers that courtesy, posting at SkS is conditional on compliance with the comments policy. Anybody who has already responded to this post on this thread may wish to move the comments to the appropriate thread themselves as all responses will be deleted shortly.
60367. Tom Curtis at 09:47 AM on 11 April 2012
       CO2 measurements are suspect
       wusgaimd, would you care to inform us which volcano is contaminating the CO2 measurements at the South Pole (shown @53 above)? For comparison, here is the full Keeling Curve from Mauna Loa:
60368. Bob Lacatena at 09:46 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       william, A suggestion... use scholar.google.com to search for papers on the subject, and look at them. They aren't as hard to read as you might think, and are far more valuable than a blog by someone who is sort of thinking about things. That said, this has been discussed at length in the literature, and a great debate is raging because nothing ever seems to adequately answer the question that balances all of the ledgers in both quantity and timing. Specifically, I've seen references to methane release from peat bogs, huge fires in peat bogs (turning the methane and other carbon directly into CO2), and numerous other ideas thrown around. BTW, while copies of papers are usually behind paywalls, I've very often found downloadable PDFs (often by including type:pdf as a search term in a regular google search, although it doesn't work on scholar.google.com).
60369. william5331 at 09:16 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       The production of CO2 from warming oceans, or at least a reduced absorbtion of same sounds feasible as a feedback mechanism to explain the accelerated melting of continental ice sheets. I wonder, though, if there wasn't another feed back. When you consider the depth of the ice sheets and hence the pressure at the bottom, all seeps of methane, and for that matter, Carbon dioxide, from shale, coal and hydrocarbon deposits plus organic decay would have collected as clatrates at the bottom of the ice sheet. These would have been released at each Milankovitch nudge. If the output of these gasses was sufficient a run away melting could have occurred http://mtkass.blogspot.co.nz/2011/09/continental-glacier-meltdown.html
60370. Tom Curtis at 09:13 AM on 11 April 2012
       CO2 measurements are suspect
       danielc's comment of 6:14 AM, April 11th, 2012:

       "@wsugaimd: Go here: Movie showing CO2 levels measured over the last 50 years it includes information from ice cores, and there are MANY data points, not just at hawaii. Go here: impact of eruptions on global CO2 levels - essentially unmeasurable. and go here: satellite measurements of CO2 compared to Mauna Loa Being skeptical of measurements taken at one point, using one method is reasonable, but CO2 measurements have been made at many, many points using many, many methods...

       Jim Eager's comment of 6:21 AM, April 11th 2012:

       Wsugaimd @38, your skepticism seems highly selective, since Mauna Loa is not the only location where atmospheric CO2 is monitored. Similarly, ocean pH is monitored at many locations around the globe. If you are truly skeptical then you should be noting what those locations also show, not just those in Hawaii. As for comparing human CO2 emissions to total CO2 content of the atmosphere, your 1% figure suggests that you are no skeptic, but rather that you are using the trace gas argument distraction (see the "Argument" button in the top bar). Consider that every single natural source of CO2 is offset by a natural absorption of CO2. The ocean continuously exchanges CO2 with the atmosphere, making it both a source and a sink for CO2. However, it is currently a net sink, meaning it absorbs more CO2 than it emits, which is why ocean pH is decreasing. Similarly, the terrestrial biosphere both emits and absorbs CO2, and it, too is currently a net absorber, although that may well change. Even volcanic emissions of CO2 are offset by geologic sequestration of CO2 via silicate rock weathering and calcium carbonate shell deposition on the sea floor. However, there is no human absorption of CO2. Zero. There is only human emission of CO2. Every gram of CO2 we emit must either be absorbed by a natural sink or remain in the atmosphere. Fortunately the ocean, biosphere and lithosphere absorb 100% of natural emissions, *plus* roughly half of the carbon that humans emit, leaving only half of it to accumulate in the atmosphere. In other words, we humans have been responsible for 200% of the measured 38% increase in atmospheric CO2. A true skeptic should be able to tell the difference between a 1% annual emission rate and a 38% cumulative increase, don't you think?"

       danielc's comment of 6:33 AM, April 11th 2012:

       "@Jim Eager #42: The argument I like to use is this: Say you have 10,000 dollars in the bank (that's 1 million pennies). 300 of those pennies are red pennies, and they earn triple interest. Every day, I am going to add three red pennies to your bank account. For every time you earn triple interest, another free red penny is added to your bank account (positive feedback). Are you going to refuse? NO! Are the red pennies in your account, and the extra red pennies I add year on year (and the triple compound interest they receive going to add significant amounts of money to your account? YES! Esp. over significant amounts of time."

       Moderator Response: TC: The three quoted comments above are in response to wsugaimd's of topic comment here, and have been quoted here in lieu of simple deletion.
60371. danielc at 07:22 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       @Sphaerica: I just went to a talk given regarding this issue... there are folks trying to use high-frequency lake bed deposits as proxies to "tune" the orbital predictions... in the Triassic!! Woot!
60372. Lionel A at 07:07 AM on 11 April 2012
       Monckton Misleads California Lawmakers - Now It's Personal (Part 2)
       Dana on Monckton and attribution, yes I have already nailed some of those but will be out of action for about 24hrs now before I can post my completed my response over at Concordensis.
60373. Bob Lacatena at 06:57 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       Karamanski, To clarify Daniel's comment, should it not be clear to you (and it wouldn't be, if you don't understand the reference to the 3-body problem)... the issue is not that the Milankovitch cycles don't apply or or that they do apply but their power "fades" further back in time. It instead refers to the fact that prediction the motions of more than 2 bodies whose mass, velocity and position all influence each other, becomes quite complex. Figuring out exactly where all of the planets were that far back, and how they all influenced each other, gets harder and harder the further back you go, while every bit of error or uncertainty introduced makes it even harder to go further back than that. Hence... it's really hard to understand that aspect of the problem.
60374. danielc at 06:53 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       addendum: The authors use Laskar, 2004 to get a "best look" at the orbital forcings, but keep in mind that those forcings are quite noisy, and there is a lot of chance for significant error... the other data they use to constrain global temperatures certainly help... but there are a lot of unconstrained variables in play.
60375. danielc at 06:50 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       @SPhaerica the other issue with milankovitch cycles is that the orbital predictions start to break down the further back in the past you get - classic three body problem issue... http://www.astro.gla.ac.uk/honours/labs/solar_system/papers/laskar.pdf There are problems with using milankovitch orbital forcing models on rocks that are that old... those problems are somewhat surmountable if the system can be "tuned" with verifiable independent data sets....
60376. Bob Lacatena at 06:43 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       2, Karamanski, The answer to your question is in the post above, but perhaps it's not clear due to the way it's described. The climate of any age depends very, very much on many factors, including ocean currents and the configuration of the continents. As such, simulations are necessary to try to determine exactly which orbital configurations might have resulted in the observed events, and why. At the same time, the theory of Milankovitch cycles itself is fairly new, and by itself only explains the trigger for glacial/inter-glacial transitions, but not by itself the entirety of those transitions. So... Milankovitch cycles are "orbital variations," or rather occasional configurations of various orbital factors that combine to create certain conditions. Similarly, De Conto et al were attempting to achieve that same understanding of how orbital factors might have influenced the Paleogene. So your answer is... similar in nature, and some day they might even call them "the Paleogene Milankovitch variations," but calling them Milankovitch cycles and then expecting to see the same variations is overly simplistic.
60377. danielc at 06:33 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Jim Eager #42: (snip)
       Moderator Response: TC: Of topic comment snipped and moved to the appropriate thread. Further of topic comments will simply be deleted.
60378. Karamanski at 06:29 AM on 11 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       Are the orbital variations that instigate the hyperthermals the same as the Milankovitch cycles that drive the glacial-interglacial oscillations? The 1.8-1.2 million year periodicity of the suspected orbital cyles seems inconsistent with the 100,000yr, 41,000yr, and 21,000yr periodicities of the Milankhovitch cycles. Could someone please explain this?
60379. Jim Eager at 06:21 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Wsugaimd @38, (snip)
       Moderator Response: TC: Of topic comment snipped and moved to the appropriate thread. Further of topic comments will simply be deleted.
60380. Alex C at 06:17 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       To keep the thread on topic, if people would not further respond to wsugaimd, that would be appreciated. The references to pertinent threads are appreciated, but let it go from here.
60381. danielc at 06:14 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @wsugaimd: (snip)
       Moderator Response: TC: Your off topic comment has been moved to a more appropriate thread as suggested by DSL @39. At SkS we try to keep discussions on topic both in order to keep them focused, and in order to make it easier for our readers to find the appropriate discussion. Your comment was, IMO, particularly informative and I hope wsugaimd lives up to his claim of skepticism by following the link and reading your comment, not to mention the relevant article. Further of topic comments will simply be deleted.
60382. DSL at 06:09 AM on 11 April 2012
       CO2 measurements are suspect
       wsugaimd, how do you explain the Keeling Curve? The steady rise of atmospheric CO2 cannot be explained by a nearby volcano. Also, the Hawaiian measurements are corroborated by independent measurements. Read the article above.
60383. DSL at 06:04 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       wsugaimd, if you are truly skeptical, then you will respond to the response you're about to get. First of all, let me point you to the appropriate threads for each of your arguments. Responses to your comment should be placed on the appropriate threads: CO2 measurements are suspect OA Not OK
60384. John Hartz at 05:51 AM on 11 April 2012
       2012 SkS Weekly Digest #14
       Charlie A: For the record, I accorded a "Hat Tip" to Joe Romm for this particular cartoon because he had posted it first. My H/T does not have anythiong to do with the Romm article that you have found fault with. If you want to critque Romm's article, you can do so directly on his website.
60385. John Hartz at 05:46 AM on 11 April 2012
       2012 SkS Weekly Digest #14
       Charlie A: "Toons of the Week" are chosen for their ability to make people laugh and/or cry as the case may be. They should not be, an indeed cannot be, equated to a an article based upon peer-reviewed science. You have made your point about this particlur cartoon so let's move on.
60386. wsugaimd at 05:38 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       I have to be honest here. I am a skeptic. And heres why. I live on the slopes of Mauna Loa, not too far away, is the Mauna Loa Observatory (MLO) where the famous Keeling Curve was made. Its located at the 9000ft elevation(I've been there several times) and just below it, at the 4000 ft level is the most active volcano, Kilauea and its sister, Pu'u O'o vent which has been continuously erupting since 1983. Atmospheric inversions can bring up the C02 to the MLO and causes astronomical spikes in C02. Oceanic acidification data has come from the University of Hawaii Aloha research station located 100km N of Oahu...just at the edge of the great plastic debris field, which is being enhanced by 25 million tons of debris from the Japan earthquake. The biological activity in this area is logarithmically increased due to available surface area of this debris. And with the increased metabolism, there is significant release C02 and organic acids which decreases the pH. Also, the amount of sulfuric/sulfurous and hydrochloric acid from the volcano emissions blows over this area(estimated between 2000-10,000tons/day). With Kona winds, the vog plume blows over the Aloha Station, and currents regularly carry this acidified water to this area. Man also produces 27 billion tons of C02/yr but this is released into an atmosphere that already has 3,600 billion tons. Do the math and man puts out three fourths of 1% of all C02. Seems quite small.... These and other questions have always made me "skeptical".
       Moderator Response:

       [DB] The topic of this thread is "Shakun et al. Clarify the CO2-Temperature Lag". In the spirit of true skepticism, we do expect for you to follow up with any further questions on the more relevant threads already supplied to you by the helpful participants here. And when one "does the math" 30 gigatons of annual emissions heretofore sequestered from the carbon cycle that man is now injecting as a bolus slug back into that cycle quite scarcely "seems small".

       [Sph] wsugaimd, Please continue to be skeptical! Pursue your questions to the end. Please engage all of your questions on the appropriate threads, because they truly are very simple questions to answer, and they can be answered unequivocally, beyond all doubt. The points you raise have solid, indisputable answers.

       As such, if you pursue your skepticism, and then go beyond that to ask further questions and to properly understand the answers, you will begin to understand the problem we all face.

60387. danielc at 05:31 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Jim: absolutely correct... hence, the dry valleys in antarctica... colder = dryer, and dryer = less snow. I agree that it is a less important effect, but the cumulative impact of both hotter summers (increased melting) and colder/dryer winters (decreased accumulation) act effectively together to remove snow/ice rather rapidly. The current situation is "special" due to the fact that we are getting BOTH hotter summers and warmer winters - more melting AND more snow in winter... strange combination due to the overall net increase of CO2 (heat trapping)...
60388. dana1981 at 05:24 AM on 11 April 2012
       Monckton Misleads California Lawmakers - Now It's Personal (Part 2)
       Lionel @20 - the reason Monckton's attribution is vague is undoubtedly because as usual he's misrepresenting his sources. Last time he claimed near unanimity regarding the cost effectiveness of his do-nothing path his reference was a paper by Tol. I looked at that paper, and it actually says the opposite - that a carbon tax is the proper response. Mockton thus far has been unable to point to a single peer-reviewed economics paper that supports his do-nothing approach, let alone a 'near unanimity'. As usual, he's full of crap.
60389. Jim Eager at 05:08 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Re Daniel @ 35, while the corresponding decrease in high latitude winter insolation and consequent more extreme winter cold is less important, even this acts to inhibit ice sheet growth as reduced moisture leads to decreased snowfall accumulation and thus reduced ice formation. It's a two-prong attack on the ice sheet: less new ice formed during the colder, dryer winter, more old ice melted in the warmer, wetter summer.
60390. Lionel A at 05:06 AM on 11 April 2012
       Monckton Misleads California Lawmakers - Now It's Personal (Part 2)
       John Russell @19 I posted a comment over at the foot of that second Concordensis article and Monckton of Brenchley has Gish Galloped in including this odd statement:

       'The economic argument against acting on CO2 is even stronger than the political argument. Even if one were to suppose, per impossibile, that the 3 Celsius degrees of warming predicted by the IPCC for this century as a result of our emissions of greenhouse gases were actually likely to occur, only 1.5 Celsius of this warming is attributable to the CO2 we add to the atmosphere this century...'

       and

       'the peer-reviewed literature of climate economics is near-unanimous in concluding that it is more cost-effective to do nothing now and to pay the cost of focused adaptation to any adverse consequences of global warming that may in future occur than it is to spend any money now on climate mitigation.'

       I was trying to discover how he can come to these conclusions but have been hamstrung by poor internet connectivity and sickness. I nearly have a response to some of that gallop but his attribution is always rather vague.
60391. Composer99 at 04:26 AM on 11 April 2012
       2012 SkS Weekly Digest #14
       Charlie A: I'm sure you've been constantly pushing that same stark choice over at websites such as WattsUpWithTthat and Bishop Hill when they engage in the same, right? Right? In any event, why you can't be bothered, in your criticism of this cartoon, to acknowledge the multitudes of other articles here on SkepticalScience which thoroughly discuss the scientific literature? I trust the false dichotomy you present is just an error. Right?
60392. danielc at 04:00 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Tom Curtis: I stated "Increased Northern and Southern Hemisphere summer insolation" - meaning more heat in Northern summer (June/July) and more heat in Southern summer (Dec/Jan). Your statement is more properly worded than mine, but they mean the same thing. Also, yes there was a decrease in insolation in the same places in their respective winter seasons... but the important thing is the summer, because a change from very cold to extremely cold is not as important or as impactful as a change from cool to hot....
60393. Bob Lacatena at 03:12 AM on 11 April 2012
       2012 SkS Weekly Digest #14
       Alces, Please reference my napkin calculations here, where I conclude that:

       we would need to plant, today, redwood forests on at least 75% of all arable/agricultural land, and to allow them to grow for 100 years, before they successfully drew enough carbon (337 Gt) from the system to lower atmospheric CO2 levels back to the pre-industrial age... ...with only 25% of the agricultural land available after starting the "great carbon absorption" forests, we'll only be able to feed 25% of the 7 billion people currently alive.

60394. Tom Curtis at 02:10 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       danielc @32, with regard to your (1),the orbital change causes increased NH summer insolation and SH winter insolation. It also caused decreased NH winter insolation and SH summer insolation, as can be seen here: Caption reads:

       "Fig. 1. Comparison of insolation anomalies (16) over the past 150,000 years for 70'N (top), 50'N (middle), and 80°S (bottom). Insolation sufficient to begin major melting leading to the last interglaciation occurred only after ca. 135,000 years ago (line labeled ‘A’); an inference based on the observation that major melting over the more wel-constrained and re-cent deglaciation did not begin until the same level of insolation was reached at ca. 15,000 years ago (30) (line labeled ‘‘C’’). A much higher rate of Northern Hemisphere summertime insolation increase existed over the penultimate deglaciation (line labeled ‘‘B,’’ ca. 130,000 years ago) than over the most recent deglaciation (line labeled ‘D,’ ca. 12,000 years ago)."

60395. Lou Grinzo at 00:51 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Great article. This is a paper, like the one by De Conto et al. about the permafrost/PETM linkage, that deserves considerable attention. Taking them together, I think it's fair to say that we continue to collect evidence that the Earth System is itself "wobbly" or "twitchy", thanks to the cascade of effects that can be unleashed by even a "minor" perturbation. We may be in the process of learning that the relative equilibrium that's held throughout human history was a much more precarious balance than we generally assumed, especially those of us who are not climate experts. The implications of this inherent nature of our environment, assuming our dawning realization is correct, are very grim. They tell us that not only does it take less of a shove to knock the Earth System out of its state of equilibrium, but that once that move to a new equilibrium state (or excursion through state-space in search of a new eq.) begins, it's extremely hard to reverse the process. You can go home again, but it's much harder than we thought. For those who like physical analogies, I always think of a ball resting in the bottom of a bowl. Poke it, and it rolls around a bit but returns to (virtually) the same position. This is how we prefer to think of the Earth System. But it's looking more and more like the ball is instead resting in a shallow depression on top of an inverted and very irregularly shaped bowl; nudge it very gently and it rolls around and comes to rest in its perch. But even a moderate poke sends it over the edge and going who knows where. And not to go all Jared Diamond about it, but I think there's a strong case to be made that the basic geography of the Northern Hemisphere loads the dice in favor of rapid warming events -- all that land at just the right distance to accumulate and then release carbon, surrounding open ocean that can quickly lose ice cover and kick off the albedo flip positive feedback.
60396. danielc at 00:12 AM on 11 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @Michael: 1) Orbital change causes insolation increase in Northern and Southern Hemisphere summer. 2) Northern Hemisphere glacial ice caps melt rapidly enough to overwhelm thermohaline circulation. 3) Loss of consistent, global Thermohaline heat redistribution leads to loss of the ability to redistribute heat efficiently. 4) loss of heat redistribution is magnified in the Southern Hemisphere because of the relatively large percentage of earth's surface covered by ocean. The Southern Ocean warms up enough to release large volumes of CO2. 5) The rapid and large-volume increase in atmospheric CO2 feeds back to increase overall global temperature. Simply put: Orbital forcing leads to larger heat inputs at the poles relative to equator. The ensuing melting releases CO2 and fresh water. The fresh water disrupts thermohaline circulation, trapping heat in the oceans that would otherwise be redistributed. The CO2 released feeds back into the increasing temperature/heat greenhouse effect. If this happens fast enough, the CO2 and temperature/heat increases can rapidly overwhelm the negative feedbacks from weathering and organic sequestration....
60397. KR at 00:11 AM on 11 April 2012
       2012 SkS Weekly Digest #14
       Alces - "We have those plants. They are called trees. The output is wood. Why not grow more trees and sequester more carbon in wooden structures? When wooden structures reach the end of their lives, why not recycle the wood, perhaps as a biofuel?" Because when they get used as biofuel, or the trees otherwise decay, the carbon goes right back into the atmosphere. True sequestration will require keeping that carbon locked away (as coal, oil, and natural gas did) for tens of thousands of years while the carbon cycle and silicate weathering absorb the pulse of carbon we have released. That sequestration requires an increase of long term carbon mass kept from the atmosphere - at this point we simply don't have enough land area (even if, say, we stopped growing lower carbon density food) for high density forests sufficient to pull our current CO2 overburden out of the atmosphere.
60398. Tor B at 23:30 PM on 10 April 2012
       DeConto et al: Thawing permafrost drove the PETM extreme heat event
       Great article and useful links. FYI, the Paleogene Period consists of the Paleocene, Eocene, and Oligocene Epochs.
       Moderator Response: (AS) Oops. I'll fix that, thank you.
60399. threadShredder at 23:30 PM on 10 April 2012
       Fred Singer Debunks and then Denies
       @Moderator Response @16: I understand your policy and, of course, will abide by it. But it is a losing one. You clearly understand this is a war, and not a debate. The best way forward is to respond to deniers with the science and then you have to question their personal integrity when they refuse to respond rationally.
60400. Michael Whittemore at 21:22 PM on 10 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       I read the link, very informative, thanks. Just so I am clear, stopping of the (AMOC) forced the Southern Ocean to release CO2 which caused this feedback system. It was not the temperature rise in the southern ocean that caused it but the extra CO2. This CO2 had a g value of 0.8 leading to a 5 degree temperature increase?

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