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muoncounter at 13:20 PM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Interesting that these retired gentlemen make no mention of the scandalous work done at NASA Langley: The evidence, according to Bruce Wielicki, lies in the decades of climate records that are revealing how humans are "driving our system a thousand times faster than it's ever been driven before." ... "You can't believe a single scientist, but you can believe thousands of scientists," he said, referring to several peer-reviewed science organizations–such as the IPCC group–that have arrived at the same conclusion: Climate change is happening. An astrophysics friend with some inside contacts at Johnson Space Center recently told me of a group of 'old geezers' who would argue against climate science - they're big fans of JCurry. Anyone surprised? -
Alex C at 12:55 PM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Pogo is a term used to refer to oscillations in rocket fuel arising from uneven acceleration of said rockets as they launch. It does, however, trace etymologically back to the pogo stick toy. To not stray too far myself, I think that it's great that the Administration has responded promptly to this kerfuffle. I also think it's a shame that these former employees decided to ignore the work of current employees at NASA, and work of climate scientists from around the world, at gathering the very evidence that they say wasn't ever examined, the very evidence that has been presented publicly and on international scale for 20+ years now. -
skywatcher at 12:46 PM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
DB - thanks! That's exactly the paper I was thinking of. danielc #79, I think the answer to your question is 'no'. AFAIK there's no threshold level above or below which the WV feedback is particularly effective - the effect scales smoothly with increased temperature. Raise the temperature, add some WV. To go into more details - WV's impact is logarithmic with increasing temperature (see Tom's comment above), as with other greenhouse gases, as they are all 'bites' being taken out of the longwave IR spectrum. We would thus expect to see the impact of WV decreasing slightly with higher temperatures/concentrations of WV. However, there's so much WV in the atmosphere in relation to CO2 or CH4, that doubling the quantity is a lot harder, and so the feedback warming effect of WV will probably be effectively linearly correlated with temperature forcing. William Haas #80, you're not providing any evidence to support you ideas. Why would H2O be more readily available, given CO2 is more effective a GHG at lower concentrations? How would that WV last in the atmosphere long enough to melt glaciers and so sustain the warming (see the paper linked by DB to my above post)? "... probably a lot more going on ..." is just hand-waving, or, to be frank, appealing to leprechauns. -
Doug Hutcheson at 12:40 PM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
The list of signatories covers a wide range of expertise in irrelevant studies. I was particularly impressed by:Dr. Harold Doiron – JSC, Chairman, Shuttle Pogo Prevention Panel, 16 years
Pogo Prevention? Is that, like, to do with things that bounce up and down, like temperatures on Earth? Well, I can see the relevance then - the guy is an obvious expert, right up there with the proprietor of Monckton's Shirt Shop. WUWT managed to add value to the cause, with this little snippet:When Chris Kraft, the man who presided over NASA’s finest hour, and the engineering miracle of saving Apollo 13 speaks, people listen.
Yes, Anthony, that's the point: when someone with an irrelevant expertise agrees with your position, you choose to listen. Shame you won't do the same when a relevant expert speaks. One comment at WUWT speaks about Harrison Schmitt thusly:He’s also the only geologist to reach the Moon, and geologists have a much better “world view” about the impacts of climate change than people from any other branch of science.
Well, I'm glad that's settled, then: a geologist who has been to the moon must be an expert on everything to do with his home planet. (Takes note to self: must ask Harrison Schmitt for a second opinion on everything SkS says, to be sure I am not being misled)/sarc -
danielc at 11:34 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
So perhaps you can name a plausible mechanism in contrast to the stated, and quite simple one (i.e. that orbital forcing drove up temperatures enough to release CO2 that then amplified the forcing signal)? -
William Haas at 11:27 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
danieic, Thank you for your efforts. I understand a triggered reaction but since the world is not thermite your analogy works just so far. I think that starting a simple camp fire would also be a good analogy. Modeling is not really evidence. Especially in an ice age environment, H2O is a more readily available green house gas than CO2 that can be released with just a little surface heating. It is the oceans that heat up so very slowly from year to year that help moderate the reaction but only the very surface of the ocean, or a glacier for that matter, has to be heated to release significant amounts of water vapor. Yes, not only does the water vapor need to be produced but the atmosphere needs to be warmed to contain a larger amount. There was probably a lot more going on than just green house gasses that caused the climate to change over a period of more than 10 thousand years and the evidence that we have only gives partial information on what really happened. CO2 may have played an important part but I do not see any evidence that it had to be CO2 that caused the ice age to end. -
danielc at 11:24 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Is there a sustained level of, or a sustained rate of change of CO2 concentration that is required to sustain consistently elevated H2O(v) levels? (Did I word that right? -- What I mean is: Is there a CO2 threshold beyond which water vapor in the atmosphere will provide strong and sustained positive feedback, or is there a particular CO2 input level relative to the starting level that is required to trigger and maintain the water vapor feedback? -
Tom Curtis at 11:15 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
William Haas @74, the forcing of CO2 does not scale with the CO2 concentration but with the logarithm of the CO2 concentration. Consequently for a broad range of CO2 concentrations there is a constant change of CO2 forcing by 3.7 W/m^2 per doubling or halving of concentration. As the CO2 concentration at the LGM was 180 ppmv, and in the year 2000 it was 370 ppmv, the change in CO2 forcing is just over 3.7 W/m^2. The relevant formula is that deltaF = 5.35 * ln(C/C0) where deltaF is the change in forcing, ln is the natural log, C is the CO2 concentration and C0 is the initial CO2 concentration. This formula breaks down for very low and very high values of CO2 concentration, but is valid for the range of CO2 concentrations experienced over the last 600 million years of Earth's history. The water vapour contribution to the GHE also scales with the logarithm of concentration, although I do not know the exact formula. However, concentration increases exponentially with temperature so that the net effect is an approximately linear increase of GHE contribution with rising temperature. The major problem with assuming a water vapour driven emergence from the Ice Age is that it implies a very strong water vapour feedback. The total change in GHE between LGM and Holocene is somewhere between 50 and 100 W/m^2. If water vapour has driven that change from a small initial increase, then the climate sensitivity to a small perturbation in water vapour would be in multiple degrees. As ENSO causes fluctuations of plus or minus 5% in the water vapour content of the atmosphere, a strong El Nino such as 1998 would drive us into a new regime with radically increased temperatures. Clearly that does not happen. The reason, as others have pointed out, is that water vapour precipitates rapidly out of the atmosphere. Consequently it's concentration is strongly controlled by temperature. You should also recognize that the change in CO2 forcing between LGM and Holocene is very well established. If water vapour has a very strong self fueling feedback effect, it must have an equally strong feedback effect to the change in CO2 forcing, not to mention changes in albedo etc. So if you rely on a theory of water vapour driving the transition between glacials and interglacials you must then provide an ad hoc theory as to why the CO2 forcing did not result in an equally strong additional feedback. -
danielc at 11:13 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Thanks, skywatcher! And Thanks Moderators for both correcting my poorly formatted post and for the link to that article!! I like this site. -
skywatcher at 10:53 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
William Haas, water vapour is a feedback, not a forcing. It cannot be a forcing because it precipitates out of our atmosphere in a few days. A greenhouse effect composed entirely of water vapour would collapse to an ice-house as the water vapour precipitates out and gets locked up in ice sheets (IIRC there's a paper describing this). Thus, the amount of water vapour in the atmosphere essentially depends on the temperature of the atmosphere. The rapid hydrological cycle leads to two things - water vapour easily gets into the atmosphere as a response to warming, and it easily precipitates out again as rain. [danielc - all you need is any kind of warming to add a bit to the water vapour feedback, not a large forcing to initiate it as in your analogy]. CO2 forcing provides the backbone for the other feedbacks to operate, as the CO2 cannot precipitate out quickly, lasting hundreds of years in the atmosphere. A feedback incorporating CO2 release, as occurred during deglaciation, leads to extended warming, long enough to melt some of the ice sheets, reinforcing the warming through a change in albedo. Our great CO2 release experiment is doing the same thing, only using a much larger and much quicker CO2 release, where the CO2 release does not depend on the behaviour of ocean ventilation... Water vapour feedback article on SkSModerator Response:[DB] Try:
Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature, A. Lacis, G. Schmidt, D. Rind and R. Ruedy, 2010
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danielc at 10:00 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
@William Haas: The increase in sunlight would not have triggered anything *on its own without the prior pre-conditions being met* -- (there are many documented cases where orbital forcing/milankovitch cycles reached the same basic arrangement of insolation and heat delivery without producing a massive and global glacial meltdown... It's that the orbital forcing trigger was pulled at a time when the conditions in the Northern Hemisphere were ripe for a magnified positive feedback response to that trigger. Let's look at it this way: Do you think that over the last 30 or so million years that Antarctica has been ice-bound and covered with that sheet, there have or have not been orbital configurations (Tilt, Wobble, Precession, Ellipticity) that have delivered large and sustained highs in Southern Hemisphere insolation? I would bet that there have been such events, and that folks who model these things and try to push the orbital cycles back beyond 5 mybp have isolated just such events... And yet none of them triggered any kind of self-reinforcing feedback in anything like the way that the NH has responded to the orbital forcing over the last 3 my or so... (at least none that I know of ... and I am certainly willing to find out/admit ignorance/learn something new!!) So, even if it is the H2O(v) that is the big bad heavy hitter in the later stages of the meltdown, it's pretty clear from the available evidence and modeling that 1) these events require (or used to require!!) an orbital trigger. That the orbital trigger cannot set off the H2O(v) runaway by itself, it needs to "stage up" using more readily available, more readily releasable, GHGs to reach the threshold where there is continuous and sustainable increases year on year in GHG release and H2O(v) maintenance. I like to think about Thermite reactions when considering how this must work : 1) if you have a chunk of iron and a chunk of aluminum and a good fuse (magnesium), you have all the material you need to make thermite with not much effort.... but you cannot do it with the materials in their starting state! 2) Both the iron and the aluminum must be in the proper oxidation/reduction state, and the heat trigger must be arranged in such a way as to produce the proper amount of heat to overcome reaction barriers. 3) so only after you've powdered both metals and ensured that the Iron is in the Fe(III) oxide form and the Aluminum is pure metal (no oxides), and then mixed/homogenized the powders ... then you must trigger the reaction by attaining an ignition heat, where the magnesium comes in. So you light a match (low temperature, short lived, tiny reaction), and that lights the magnesium (much higher temperature, but slow burning, calm reaction). The lit magnesium melts the two metals at a high enough temperature that the molten aluminum (very hot!) reduces the oxidized iron in a massively exothermic (even hotter!) reaction that requires a lot of activation energy. The reaction is essentially self-sustaining, given enough reactants mixed appropriately - it supplies its own oxygen, it produces enough heat to keep the reaction going, and under water, it is hot enough to generate hydrogen, rather than quenching or smothering. So, with a little bit of sugar burning (in the muscles of your hand), you ignite a match that produces a bit of heat for a short time.... that triggers a much hotter but slow burn in the magnesium, which in turn triggers a massively hot, extremely exothermic, self-sustaining, un-smotherable reaction between Al and Fe2O3. If reactions like that can be easily envisioned and reproduced (I've done it in my backyard, and even did it with copper instead of iron, just for laughs), and involves multiple stages and triggers to climb the entropic ladder, then why would it be hard to imagine that a bit of change in insolation can trigger a bit of warming that can release a bit of CO2 that can thaw a bit of glacier... That releases a bit more CO2, thaws more glacier, and wham... up the ladder you go, releasing enough CO2 to trigger enough melting to trap enough warm water in the right place to release even more CO2... that heats the place up enough to get the H2O(v) reactions rolling, and suddenly... Some avalanches do start with a butterfly landing on a pebble...Moderator Response: TC: Phrase between asterixes added by request; all caps turned to bold to comply with comments policy. -
William Haas at 09:57 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Tom Curtis, thank you for your efforts and all the information you have supplied. I would think that CO2 forcing would be in proportion to the amount of it in the atmosphere. How much CO2 was in the atmosphere at LGM and how much today? I realize that the water vapor effect was less during the LGM then it is now but so was CO2. But that does not really matter. What matters is what changed because it is what changed that kept the temperture increase going. According to the article it was solar energy by means of orbital cycles that triggered the end of the ice age. According to the article CO2 levels at first did not rise because it took a while for the oceans to experieice significant warming. You state that "as temperatures continue to rise, the water vapour will contribute proportionately even more to the total GHE than does CO2" It seems to me that H2O levels alone are enough to explain the GHE effect part of triggering the end of the ice age. -
muoncounter at 09:52 AM on 12 April 2012Scientist Sets Record Straight on Medieval Warming Research
Update from Syracuse available here: “It is difficult for the lay public to make informed decisions about contentious issues — particularly those concerning climate change, conservation and preservation — which require objective, scientific research and discovery when news reporters fail in their duty to write accurately about the science behind the issues.” Failure to write accurately about science is a job requirement in some camps. -
danielc at 09:24 AM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Can I post my intemperate comments now? They got (rightly) snipped from previous threads... but it was so much fun writing them, that I would love to reproduce them in full. If you let me, I promise that they will be even more choc-a-bloc full of inflammatory prose! :) -
skywatcher at 09:21 AM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Somebody should ask Schmitt if he saw any other Earths out there in the great black void of space, just in case he's wrong on his assertions about this one. You'd hope that Moon astronauts, being the only people to have seen how small the Earth is in space with their own eyes, would appreciate the value of protecting the only planet we have. A good article Dana and a good response from NASA there too. Is this kind of angry letter all the so-called skeptics have left now? It would seem so. Do they not actually have any science they can stand behind, any plausible alternative explanations explaining the full body of evidence? It would seem not. -
Tom Curtis at 08:58 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
William Haas @72, in the year 2000, CO2 contributed 31 W/m^2 of a total 152.6 W/m^2 greenhouse effect. Water vapour and clouds combined to contribute 112 W/m^2. At the Last Glacial Maximum, assuming a difference in temperatures of 7 degrees C, the total greenhouse effect dropped to about 120 W/m^2, but CO2 forcing dropped by only 4 W/m^2. If we assume a temperature difference of 4 degrees C as calculated by Shakun et al, the XXXXXXX total greenhouse effect XX dropped to 114 W/m^2. That leaves a change in greenhouse effect of between xxx 33 and xxx 40 W/m^2 to be explained, primarily by changes in Water Vapour and clouds. Even if we assume all other factors (which combined for a total 7 W/m^2 GHE in 2000) drop to zero contribution, that still leaves around xxx 26-43 W/m^2 of reduced GHE to be explained by reduction in the Water Vapour effect. These calculations do not take into account either albedo from dust, or the increased pole to equator temperature gradient during the LGM. If they are taken into account, they will explain a significant portion of that xxx 26-43 W/m^2. Never-the-less it is XXXXXXXXXXXXX highly probable that the reduction in water vapours contribution to the GHE in the LGM was greater than 15 W/m^2, and hence greater than the proportional reduction to the CO2 forcing. Therefore CO2 was a more important contributor to the total GHE at the LGM than was H2O. What is more, this is just what we would expect given the rapid decline in the saturation vapour pressure of H2O with temperature:
Conversely, as temperatures continue to rise, water vapour will contribute proportionately even more to the total GHE than does CO2. Another was of saying this is that as temperature increases, so does the relative* strength of the water vapour feedback. Running that back to the LGM means that the water vapour feedback was weaker during the last glacial than it is now. That means it was even less able to trigger a self fueled runaway effect as you are suggesting than it is now.
* added in edit, 10:17 AM
Edited 3:25 PM of 14/4/2012 to correct error in calculation as detailed below.
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Bob Lacatena at 08:05 AM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
When I was in 6th grade we all went down to the auditorium to share a moment of silent meditation wishing the best for the 3 astronauts on Apollo 13. I used to see astronauts as heroes having the courage to push the envelope as a way to better mankind and to seek the truth. Using their status and past accomplishments to express their own ignorance in an area of science completely beyond their experience is an embarrassment. It makes me feel like I wasted a part of my childhood respecting the wrong people for the wrong reasons. It shouldn't diminish what they contributed and what they accomplished -- but it does. -
William Haas at 07:40 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
67 Sphaerica Thank you for your reply. But in the article I read things like: "The first warming was indeed triggered by orbital cycles". So it is not CO2 that started the warming that caused atmospheric H20 to increase because ice is melting, water surfaces are warming, and the atmosphere is warming, increasing its capacity to hold water vapor. It is really the increase in sun light that triggered the whole thing. As more water vapor enters the atmosphere the warming continues alowing even more water vapor to enter the atmosphere. Yes water does precipitate out but it is quickly replaced. Water is still the dominant green house gas in the atmosphere and was even more so during the ice age when even less CO2 was present. I do not understand how CO2 is needed to explain what happened. -
Climate Scientists take on Richard Lindzen
Chris G - Lindzens apology was a positive indication. Unfortunately, he's been pushing much the same set of incorrect models since his (quite interesting, but quickly disproven) 2001 "Iris" paper. Which with fairly minor changes has been published yet again (3rd time?) as Lindzen and Choi 2011, in a rather off-topic journal, after being rejected from more on-topic publications. I'm not seeing any signs of recognizing and learning from past errors... -
adelady at 07:11 AM on 12 April 2012Eocene Park: our experiment to recreate the atmosphere of an ancient hothouse climate
dr2chase. Thanks for that. I have little to no experience with humidity. During extended hot periods here it's quite common to find several dead bees in the garden (when you find the courage and stamina to go outside again). -
dr2chase at 07:04 AM on 12 April 2012Eocene Park: our experiment to recreate the atmosphere of an ancient hothouse climate
Regarding bees/bats etc. Bees, I know from personal experience, are gloriously happy in a Florida climate. Africanized bees, which migrated north from Brazil, we can presume are pretty healthy in current-tropical climates. Bats do well in Florida, and do well in current-tropical climates. As a general rule, Florida was (and is) a much buggier place than Massachusetts or northern California. There's no doubt a maximum temperature for pollinators, but we're far from it right now in the US. People lived in the South (including Florida) back before air conditioning, though it wasn't a popular choice. If things go as predicted, I expect millions of people will leave Florida, much as millions of people moved to Florida in the previous century. Don't get me wrong, we are definitely rolling the dice on our present course, and they're loaded against us, but there's a difference between godawful costly and end of civilization, never mind end of a species. It's likely that there will be excess deaths, but elsewhere, and our civilization has developed and bumbled along in the face of excess deaths elsewhere for centuries, never mind the awfulness of calling that "civilization". What we call civilization, survived. -
Bob Lacatena at 06:11 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
JosHag, Thanks!!!!! -
Kevin C at 06:02 AM on 12 April 2012Data Contradicts Connection Between Earth's Tilt and the Seasons
While I wouldn't normally post an xkcd cartoon on SkepticalScience, there is a time and place for everything:
(It took me a while to get the final panel, but I'm a little slow.)
[Mouseover text: Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'.]
Moderator Response: [Sph] Added mouse-over text to cartoon image. -
JosHagelaars at 05:55 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Great post. It is maybe interesting to combine it with Schmitt et al 2012, which shows a drop in δ13Catm after 17.5 kyr BP explained as a result of upwelling old carbon-enriched waters in the southern ocean. They also report a small rise in δ13Catm before 17.5 kyr and, like Shakun, link it to rising temperatures: "After a very small increase in δ13Catm at the very end of the glacial, a sharp drop in δ13Catm starting at 17.5 kyr parallels the onset of increasing atmospheric CO2. Taken at face value, this would point to an early SST rise that preceded the onset of the CO2 increase." ... "Note, however, that this 0.06‰ excursion is within the uncertainties of our data and that other effects could also lead to this small enrichment in δ13Catm." @Sphaerica #69, the Shakun paper can be found here. -
Dibble at 05:03 AM on 12 April 2012Data Contradicts Connection Between Earth's Tilt and the Seasons
For a moment I thought you may be Bob Tisdale. A genuine Tisdale would have used at least 30 graphs to illustrate the same point. -
Chris G at 04:35 AM on 12 April 2012Climate Scientists take on Richard Lindzen
Bob, Also, the fact that he sent an apology when he made a misrepresentation indicates to me that he has integrity. (Anyone ever seen an apology from Watts or Monkton?) And, he doesn't deny basic things, like that the greenhouse gas effect exists. I think mostly he has cornered himself into an incorrect model, and is unwilling or unable to walk over the wet paint. -
Bob Lacatena at 04:28 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
68, Lazarus, If I'm reading the above analysis properly (I don't have access to the paper):- Orbital changes cause a retreat in ice sheets
- Retreat causes warming and disruption of the the Atlantic meridional overturning circulation (AMOC)
- The disruption of the AMOC plus the warming causes a faster increase in temperatures in the Southern Hemisphere
- The increase in temperatures in the led to a rise in CO2
- The rise in CO2 caused further increases global temperatures, accelerating both the SH (Antarctic) and NH temperature increases, which releases more CO2.
- Initial trigger was orbital changes causing ice melt (albedo changes)
- Ice melt added an unexpected factor in affecting the AMOC and a differential in warming in the two hemispheres
- Warming in the Antarctic proceeded more quickly, starting before CO2 release -- CO2 was a feedback in response to the warming -- so CO2 lagged Antarctic temperatures by 800 years
- Warming in the Northern Hemisphere proceeded more slowly, primarily driven by CO2, so CO2 (still, as a slow feedback) drove global temperatures higher and led temperature increases.
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CBDunkerson at 04:23 AM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Response from NASA If I may paraphrase slightly, 'Hey, you guys are full of it... and feel free to publish some actual scientific research on the subject if you want anyone to take you seriously.' -
Chris G at 04:17 AM on 12 April 2012Climate Scientists take on Richard Lindzen
Bob, I make no claim as to the correctness of his numbers, but he is competent with math. I was just looking for his idea of a mechanism where orbital forcings could have an effect that was more than GHG forcings. That paper was what I found. And then I found where he argued against a high CO2 sensitivity and, I believe, coming to the wrong conclusion based an a faulty model. The model, and hence the conclusion derived from it, is wrong whether or not the math is correct. I doubt that his explanation is correct because I gather that he is invoking albedo effects that result from the orbital mechanics, and there can be a two-way interaction between albedo and CO2 content. The same conditions which lower the albedo can cause melting of permafrost leading to release of CO2 and methane. Increasing GHGs without changing the orbit or tilt can also lower the albedo by reducing the extent and duration of snow and ice cover. Since they interact, it would be tricky to attribute x warming from one and y warming the other. By the time the feedbacks play out, it might not matter. (Kind of like vector math; it all adds up the same.) I'm thinking that if the interaction between the feedbacks and forcings were low, then he might not be entirely unjustified in claiming different sensitivities. However, it can be measured that the earth is not currently in equilibrium; more energy is coming in than is leaving. That by itself kills the idea that we have already seen the effects that the current level of CO2 will produce. So, there is a lag, and the existence of a lag mandates the existence of the third possibility that Lindzen tries to avoid. -
shoyemore at 03:10 AM on 12 April 2012NASA Climate 'Skeptics' Respond with Science! Just Kidding.
Pity all of us who read and contribute to blogs have to spend time reading and/ or discussing material about this latest red herring. If anything, the watching public must have it dawning on them that science denial has no shot in its locker except for a series of publicity stunts. The fact that the spokesman Harrison Schmitt is a board member of the Heartland Institute should almost be enough to discredit the whole letter. -
Lazarus at 02:45 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Perhaps I need something spelling out to me - but does this paper show why there is an 800 year lag just in the Antarctic proxies? -
Bob Lacatena at 02:18 AM on 12 April 2012Data Contradicts Connection Between Earth's Tilt and the Seasons
WUWT Headline:Skeptical Science Admits that Earth's Tilt More Important in Climate then CO2
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MarkR at 02:08 AM on 12 April 2012Data Contradicts Connection Between Earth's Tilt and the Seasons
Shouldn't this have been submitted to WUWT as new analysis? -
Bob Lacatena at 01:24 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
65, William, To clarify Dana's point a little further... H2O responds very, very quickly to changes in temperature, as you yourself noted. As such, it is a fast feedback... raise air temperatures a little, water evaporates, and raises them even more. Cool the air a little, water condenses, and lowers them even more. But H2O never magically injects itself into the air on its own. Some temperature change is required to cause the H2O changes. Changes in solar insolation due to albedo changes (ice sheet growth or retreat), due to dimming aerosols (volcanic eruptions) or due to solar output changes (due to changes in solar activity or orbital configurations) represent one category of forcings. Changes in greenhouse gas concentrations (CH4, CO2, NO2) represent another forcing AND slow feedback -- i.e. something that need not be directly caused by temperature changes but can be, although in longer timeframes than the more rapidly changing H2O concentrations. -
Jim Eager at 01:10 AM on 12 April 2012Human CO2 is a tiny % of CO2 emissions
Wsugaimd's claim to be coming from a biology background and his apparent lack of understanding of the recycling of carbon through respiration and its role in the fast carbon cycle seem to be fundamentally irreconcilable. -
dana1981 at 00:59 AM on 12 April 2012Shakun et al. Clarify the CO2-Temperature Lag
William @65 - remember that water vapor is only a feedback, its atmospheric concentration dictated by the temperature of the atmosphere. The atmosphere has to warm first - that warming generally being caused by CO2 and other GHGs. -
caerbannog at 23:16 PM on 11 April 20122012 SkS Weekly Digest #14
caerbannog, while your 'Sparse Stations Index' presents a solid case I doubt it will sway most skeptics. The relative who seemed impressed presumably trusts you to be honestly representing the data...
My goal isn't so much to convince die-hard skeptics as it is to undermine them. What I'm trying to do is put together easy-to-understand, easy-to-visualize arguments that show "reachable" people how completely unreasonable and untrustworthy AGW-skeptic claims are. So to that end, I've been trying to "pass out the ammo". Don't know how effective this approach really is, but I figure that it can't hurt. -
Charlie A at 22:56 PM on 11 April 2012Hurricanes aren't linked to global warming
#46 Manny asks for updates on hurricanes vs climate change .... The latest IPCC assessment on extreme weather, including hurricanes, is the SREX report released last month. Chapter 3, Changes in Climate Extremes and their Impacts on the Natural Physical Environment (20MB pdf) The section on tropical cyclones runs from page 158 to 163. Regarding observations, SREX differs significantly from IPCC AR4, and says (page 160): Based on research subsequent to the AR4 and Kunkel et al. (2008), which further elucidated the scope of uncertainties in the historical tropical cyclone data, the most recent assessment by the World Meteorological Organization (WMO) Expert Team on Climate Change Impacts on Tropical Cyclones (Knutson et al., 2010) concluded that it remains uncertain whether past changes in any tropical cyclone activity (frequency, intensity, rainfall)exceed the variability expected through natural causes, after accounting for changes over time in observing capabilities. The present assessment regarding observed trends in tropical cyclone activity is essentially identical to the WMO assessment (Knutson et al., 2010): there is low confidence that any observed long-term (i.e., 40 years or more) increases in tropical cyclone activity are robust, after accounting for past changes in observing capabilities. Regarding possible changes in hurricane intensity, SREX notes that there is a correlation between SST and intensity which at first glance would imply that global warming would increase hurricane intensity. But SREX then goes on to note However, there is a growing body of research suggesting that local potential intensity is controlled by the difference between local SST and spatially averaged SST in the tropics (Vecchi and Soden, 2007a; Xie et al., 2010; Ramsay and Sobel, 2011). Since increases in SST due to global warming are not expected to lead to continuously increasing SST gradients, this recent research suggests that increasing SST due to global warming, by itself, does not yet have a fully understood physical link to increasingly strong tropical cyclones. (crude translation .... both warm water and a temperature differential is needed to form and intensify hurricanes, and global warming does not necessarily increase differentials) -
chriskoz at 21:39 PM on 11 April 2012Climate Scientists take on Richard Lindzen
We have a proof from icecores in last 800ky, that Lindzen talk about equilibrium sensitivity of 1K max is nonsense. The CO2 levels have been varying 180-280ppm while temps at the poles have been varying by as much as 10K. Taking into account the polar amplification, the average temps still varied by some 5K. 5K with no more than 60% of CO2 change, in those last 4 inter/glacials. These are reconstructed facts rather than climate models, and suggest the equilibrium sensitivity even higher than that of IPCC models. How come is is now "1K for doubling CO2"? I wander what Lindzen and his supporter can say about that. -
William Haas at 21:27 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Really nice article. To enhance or continue global warming is atmospheric CO2 really necessary to explain it? What about H20? Particularily over ice fields, as ice melts the level of water vapor in the atmosphere increases dramatically and causes the atmosphere to warm because of green house heat trapping effects. The warmer the air the more water vapor it can hold. To cause significant increases in atmospheric water vapor only surface water needs to be warmed. A much larger volume of water needs to be warmed to cause significant increases in atmospheric CO2. I would think that starting with an ice aged earth, H2O would dominate any green house gas triggering effects. -
CBDunkerson at 21:02 PM on 11 April 20122012 SkS Weekly Digest #14
caerbannog, while your 'Sparse Stations Index' presents a solid case I doubt it will sway most skeptics. The relative who seemed impressed presumably trusts you to be honestly representing the data... the majority of 'skeptics' don't have that personal connection and have long since adopted a stance of holding that all data disproving their views must be 'faked'. Further, I suspect that a similar, though actually biased, approach could be taken by 'skeptics' to show a very different result. Your 'longest record' methodology would effectively result in the trend for each station being randomly selected. What would happen if someone instead took the station with the lowest trend in each of the four regions and averaged those together? It would probably show slight cooling over the period, and certainly wouldn't line up with the GISS results at all. That said, there should be some fraction of the total data set where even taking only the stations with the lowest trends would match GISS fairly well... as the few outliers would be averaged out by the vast majority of stations roughly in line with the global trend. Your approach is a solid refutation that any reasonable person would accept... but if 'skeptics' were reasonable they'd have accepted the countless previous analyses showing irrefutable warming. -
MA Rodger at 19:09 PM on 11 April 2012New research from last week 14/2012
Henriksson et al 2012 (Analysis of quasiperiodic 50-80 year oscillation in global temperature record) will give them there numerologists a lot of ammo with their quest for evidence of natural causes for rising temperatures. Then the paper itself appears not far from being simple curve fitting. The paper begins its introduction (but strangely not its abstract) "Periodic or quasi-periodic natural climate variability could provide part of the explanation as to why global mean temperature has been nearly constant for a decade despite risng greenhouse gas concentrations (Semenov et al 2010)." which isn't an encouraging start-point and politely mention only "near-constant" or "declining" global mean temperatures in the abstract but the flip side is there ready & waiting for WUWT to jump on. Their wobble searching (eg in the CET) shows a sign of some respectability and there is one point of interest in the identification of this wobble in the output from a model. Now that should then lead to an analysis of why the model turns wobbly & so whether the wobble is an actual phenomenon or an aberent artifact. Well, it would if you weren't distracted trying to prove reasons for wobbles in recent global temperature records. -
Eric (skeptic) at 19:03 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Missing from the see saw discussion and from figure 5 is ice age dust. As warming commenced in the SH, dust values did not change immediately but dust sources started to become vegetated. As that became more prominent, the NH warmed. For dust by latitude see fig 1 here: http://www.rem.sfu.ca/COPElab/Claquinetal2003_CD_glacialdustRF.pdf -
Michael Whittemore at 16:36 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
By the look of figure 4 above, it would seem that CO2 might have lagged behind the temperature change in the regions 0-30N to 60-90S. Due to the extra cooling that is seen in the 30-90N zone, when averaged altogether with 0-90N proxy's, makes it look like the whole Northern Hemisphere lagged CO2. When this might not be the case. -
caerbannog at 16:32 PM on 11 April 20122012 SkS Weekly Digest #14
Just for fun, I thought that I'd "take it to the next level" with respect to computing global-average temps from the minimum number of rural temperature stations. Set up a couple of processing runs with just 8 and then just 4 rural stations -- corresponding to 90deg(lat)x90deg(long) and 90deg(lat)x180deg(long) global grid sizes, respectively. As you can see, the global-warming signal begins to emerge from the noise with data from as few as 4 to 8 stations. In statistical detection theory, the proper technical term for this level of signal detection performance is "Slam-Dunk". And yes, skeptics, before you ask -- I used raw data.
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Michael Whittemore at 14:33 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
So it would be fair to say that when the (AMOC) stopped, the northern hemisphere cooling would have over powered the Milankovitch forcing and allowed the (AMOC) to start again? -
danielc at 14:27 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
@Dana Critical point being that it is a control knob that will not move unless nudged... the nudging is key, and that is the Milankovitch forcing... Why is it so hard for deniers to grasp this very basic concept? (I know, I know, it's NOT hard, but it interferes with their ideologically (inflammatory snipped) driven requirements.Moderator Response: TC: In compliance with the comments policy, please try to avoid suggestions of impropriety. Thankyou -
dana1981 at 14:21 PM on 11 April 2012Shakun et al. Clarify the CO2-Temperature Lag
Michael @59 - I'd agree with that statement. The orbital forcing is too small to cause a lot of surface changes on its own. The CO2 feedback/forcing is critical in that respect, which is why it's the main control knob. -
Bob Lacatena at 14:08 PM on 11 April 2012Human CO2 is a tiny % of CO2 emissions
wsugaimd,I believe the C02 exhaled by...
I see this a lot from skeptics.... sentences that start with "I believe." The thing is, of all things, the accounting of CO2 is done and solid. There is no wiggle room there. We know how, we know how much, we have multiple lines of evidence to prove that it cannot have come from any place else. I personally think the most complete link is this one but there are many others. Click the "View All Arguments" link below the thermometer at left, search the the page for CO2, and you'll find that every thing you have brought up has been thought of by others, and holds no weight whatsoever. Please take the time to study the information that is already available. You can "believe" what you choose, or you can educate yourself. The choice is yours, but falling back on your "belief" hardly entitles you to lay claim to the mantle of "skeptic." -
Manny at 13:57 PM on 11 April 2012Hurricanes aren't linked to global warming
No updates on hurricanes vs climate change over the past 18 months: has the issue been settled, and what is the conclusion?
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