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Berényi Péter at 07:26 AM on 22 August 2010There's no empirical evidence
#113 KR at 06:39 AM on 22 August, 2010 If you look at Figure 2 at the top of this page, the emissivity of the Earth has decreased due to greenhouse gasses You know that's not true. Figure 2 only shows it has decreased in certain narrow frequency bands relative to the rest. The offset in the figure is arbitrary, it is not measured with acceptable accuracy at all. Also, it would be very interesting to have a look at the curve below wavenumber 710 cm-1. Arctic window, between 400 and 600 cm-1 plays a crucial role under certain circumstances.
Figure 2
About that and nooks and crannies of arctic clouds read Delamere & al. 2000. As usual, it is not about actual measurements, but modeling. However, it presents the basic concepts quite clearly. -
theendisfar at 07:13 AM on 22 August 2010There's no empirical evidence
:) Dang! 107 should say COMBINED with a D, with regards to evaporation. HTML tags are causing trouble :) I can see how COMBINES with an S could cause confusion -
theendisfar at 07:04 AM on 22 August 2010There's no empirical evidence
KR, Can you please explain what is wrong in 107? Note; Should be "Convection combine -
AWoL at 06:59 AM on 22 August 2010There's no empirical evidence
If I may be so bold as to interject and declare that I'm more with Theendisfar.Surface heat loss must be by conduction,convection and radiation.99% is lost by cond/convect. Radiation fom the surface is trifling and as for "back radiation"...no go,completely contrary to 2nd Law of thermodynamics.There is no greenhouse(ie limiting of heat loss by convection)in operation whatsoever.Arrhenius was wrong.The greenhouse effect is a complete misnomer.The model of the atmosphere that is conveyed to the general public is simply wrong.Gravity and surface pressure accounts for the "warm" atmosphere....and not CO2 or any other gas. To mentally image the effect of CO2 on the atmosphere that some claim, then each molecule of CO2 would have to be a 2 bar electric fire with a parabolic mirror directed earthwards.Moderator Response: If you really want to argue about the 2nd law of thermodynamics, please start by reading the post "2nd law of thermodynamics contradicts greenhouse theory." If you still aren't convinced, read the more detailed material that you get to by clicking the links in the "Further Reading" green box below the post. Still want to argue? Then please read the comments on that post first. To save everybody the time of repeating all that. Again. -
Tom Dayton at 06:54 AM on 22 August 2010There's no empirical evidence
theendisfar, I agree with the other respondents. Your explanations are gibberish. By that I mean "nonsensical." I can't even argue against it, because it is so confused. You really need to set aside everything that you think you know, and read some very basic explanations. -
theendisfar at 06:52 AM on 22 August 2010There's no empirical evidence
Ian, This is just gibberish. I cannot follow what you are trying to say. I doubt that even you know what you are saying. Sorry, Temperature is a measure of kinetic energy within a given volume. Kinetic energy, when viewed as Force and when divided by Volume, can be represented as Pressure. The higher the density per unit volume, the higher the temperature or 'pressure'. You can simply replace 'energy pressure' with 'Temp...', and that should clear things up. Oh, and to be clear, any references in those posts to 'Law', all apply to the 3 Laws of Thermodynamics. 4 if you count the Zeroth Law, which seems obvious, but I imagine it has some use. You are right to doubt me. AGW is real and is caused by an increase in CO2 and other green house gases. No other science can dispute that statement. ? That is not gibberish, but understand that I am not so experienced as you, so my ability to read between the lines is not as refined. For give me but I only got, basic English mind you; "AGW is real and is caused by an increase in CO2 and other greenhouse gases." -
JMurphy at 06:39 AM on 22 August 2010Can't We At Least Agree That There Is No Consensus?
Poptech wrote : "So yes I told them the reason why I listed them and under what criteria." You just can't help yourself, can you ? Lucky you're around to tell these authors how their papers were something that they didn't think they were, and how they were wrong to ask for their papers to be removed/mystified as to how anyone rational could see in their papers something that wasn't actually there. Amazing. -
There's no empirical evidence
theendisfar - Nope. Your posts here, here, in fact all of your posts on this thread - nope. At the top of the atmosphere the only energy pathway is radiation. If you look at Figure 2 at the top of this page, the emissivity of the Earth has decreased due to greenhouse gasses - so that since the 1970's, at the 1970 temperature of the Earth, it wasn't radiating as much as it received. Energy accumulated, the temperature of the Earth/atmosphere increased, and and the energy radiated to space increased as well. It got warmer. In the simplest view possible: The equilibrium temperature of IR cooling bodies (energy output) with equal energy inputs and different emissive spectra depend on the integrated energy of their emission spectra - objects (or planets) with lower integrated spectra will come to equilibrium at a higher temperature than objects closer to a black body spectra. Note that greenhouse gasses tend not to affect the visible wavelength energy coming from the Sun - I think less than 1% (numbers, anyone?) of the solar spectra is in the affected IR bands. So the input energy does not change. CO2 directly reduces the emissive IR spectra of the Earth - and temps go up as a direct response, as the Earth system moves back to equilibrium energy exchange at the top of the atmosphere. -
JMurphy at 06:33 AM on 22 August 2010What were climate scientists predicting in the 1970s?
RSVP wrote : "The hubris has to do with wanting to believe we have all the answers, when in reality the problem is much more complex than we think." How has said that they have all the answers ? And the only hubris I have ever seen on this site has been from so-called skeptics claiming that they know better than scientists who spend their working lives on the problems and complexity that is Climatology, and claiming that their pet theory has never been thought of before and is a better answer than AGW. There never seems to be any complexity involved when the so-called skeptics make their bold assertions - they have usually come up with the answer while surfing the Net and discovered secret knowledge from playing around with figures and seeing patterns that no-one else has ! -
scaddenp at 06:19 AM on 22 August 2010There's no empirical evidence
theendisfar - I am sorry but would appear to have an extremely flawed understanding of physics which is guiding you to some very wrong conclusions. I have no idea where you got this from but short of starting again from a text book, how about you look at science of doom. Its impossible to have a discussion with any meaning in face of this kind of misconception. -
Doug Bostrom at 06:16 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
An apology for: "Without going into motivation, Yes, I think many climate scientists are purposely misrepresenting conjecture as empirical and repeatable evidence quite frequently using subjective terms to provide wiggle room and plugging conjecture into GCM's, passing the predictions off as reliable. That statement seems quite purposeful, almost a recitation, perhaps reflective of something oft-repeated and deeply seated. I wonder if the apology is based on a durable internal integration of actual contrition, or is simply a facile way of being assured of continued conversational stimulation? -
Berényi Péter at 06:03 AM on 22 August 2010The Past and Future of the Greenland Ice Sheet
#57 Peter Hogarth at 01:18 AM on 22 August, 2010 One of the points of this post is that there is plenty of evidence and peer reviewed research which shows that the Greenland Ice Sheet volume has varied in step with the NH high latitude temperature variations in the past, see Vinther 2009 Yes, no question about that. However, it is the rate of change we are talking about here. I have copied Figure S2 b here from the Supplementary information to Vinther 2009.
As you can see depositional elevation over the Greenland ice sheet has decreased by 200 m during 8 millennia when both local air and sea surface temperatures were 2-3°C higher than today. That translates to a rate of -2.5 m/century. The area of the ice sheet is about 1.78×106 km2. Therefore the century scale loss of ice volume was 4400 km3 what makes 4000 km3 meltwater. Surface area of all the seas is 3.6×108 km2, therefore it implies an eustatic sea level rise at a rate of about 11 mm/century. Hardly alarming, even if we take into account that holocene melt rate was highly variable, for short periods it could have been 3-4 times the average.
Eight thousand years of ice sheet response is a bit better sample from a climatic point of view than a decade. You guys are making a fuss about weather noise.
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theendisfar at 05:58 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Ian, As for Popper, I simply looked up 'falsification' and his descriptions of how to reinforce a theory were very similar to the methods I was instructed on. I never heard of him till today either. I didn't recognize that I invoked someone hostile to your position, so in my own words. Quickly, I was taught to: 1. Prepare a Hypothesis statement that had the opportunity to be confirmed or denied with the ability to test within mind. 2. First attempt to confirm the hypothesis to see if I was on track using known Laws of physics and methods. 3. If no methods were available, determine and execute a method to confirm. If no method to confirm can be found, the exercise is over since this can only lead to falsifying a negative. Proving the unverifiable is a futile exercise. 4. Once evidence is obtained, this is the important part, try vigorously to break the hypothesis with the ferocity as the biggest skeptic would apply. 5. Once I was not able to break my hypothesis, I was to ask a trusted colleague to attempt the same. 6. Once they could not, though it would be better to have it reconfirmed again by someone who respects you, then it was safe to publish, with all the methods, conclusions, and areas that might lead to falsification for the Skeptical community to confirm or deny. I was taught to expect hostility, especially if what you were proposing was especially novel or would impact your audience in a dramatic way. This an other streams validate this all too well. To me, this method (I was taught it under the name 'scientific method') renders consensus/opinion moot which vastly reduces the number of questions that could arise. Does this seem at all unreasonable? Do you have a better method? -
theendisfar at 05:32 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
sorry link was deleted for some reason http://www.skepticalscience.com/argument.php?p=3&t=107&&a=105#22448 -
theendisfar at 05:30 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
:) Ian, I must man up and recognize my inflammatory comments have invited this level of scrutiny. I'm afraid that you quoting Popper does not equate to a scientific education. You are correct. Assume I have no proper education in any sense other than I am indeed the one typing these posts and I'm not simply reciting this to someone to make up for my lack of reading and writing abilities. Heck assume I'm using voice software to read and write these messages if it pleases you. I repeat that my statements going forward are of my understanding and not simply recited from other sources. I recognize your vastly superior titles, tenure, and intellect. I invite your rebuke. -
Ian Forrester at 05:17 AM on 22 August 2010There's no empirical evidence
theendisfar re 107, 108, 109 and 110. This is just gibberish. I cannot follow what you are trying to say. I doubt that even you know what you are saying. AGW is real and is caused by an increase in CO2 and other green house gases. No other science can dispute that statement. -
theendisfar at 04:53 AM on 22 August 2010There's no empirical evidence
Ian, 107, 108, and 109 cont . . . From 109 No energy has been created or lost, the system has only lost it's ability to cool an additional 2 Watts at the speed of light and instead has to cool at the speed available to convection. Now this begs the question, is the difference in the cooling rate enough to create a back pressure that holds the energy at or near the surface increasing that region's pressure/temp? My understanding is that the elasticity of the atmosphere combined with the readily available room for an increased convection rate will offset that kind of back pressure. No energy was created or lost from my understanding, I believe I have met all Thermodynamic Laws. Will save that in the event I am understanding this incorrect. -
Ian Forrester at 04:45 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar said:I can only offer that this paper accurately describes the scientific education I received and has been reliable to me.
I'm afraid that you quoting Popper does not equate to a scientific education. In my over 40 years as a scientist (undergraduate, graduate, post doc and work as a research scientist) I had never even heard of Popper until I found him discussed on creationist anti-science sites. Shortly thereafter I found his name used by AGW deniers. Anyone, in my view, who uses Popper to support science is probably an anti-science sufferer. Does this mean that scientists are not aware of his theories? No, we called it sticking to the scientific method and real scientists still follow this regime. The theory of AGW is valid not because of all the results confirming it but because no-one has produced one iota of evidence disproving it. Non-science editorials and opinion pieces by AGW deniers do not count as scientific evidence. -
theendisfar at 04:36 AM on 22 August 2010There's no empirical evidence
Ian, 107, 108 continued . . . A uniform surface creates equal pressure going up and will have equal resistance going down. Varying the surface in both energy pressure and specific heat allows for currents to form which allows for an increased convection rate. Land Sea breezes come to mind. While the surface and atmospheric energy pressures have adjusted, no energy has been created or lost. Now let's place a resistance on the Radiation rate. If 2 Watts is correct for CO2, that is a .005% restriction at 390 Watts. Convection rates within the Earth's atmosphere are highly variable, from dead calm to reaching dozens of meters per second. Thermal currents and hang-gliding come to mind. If a radiative resistance is encountered, and if my understanding of the 2nd Law is accurate, then any energy trapped by radiative resistance will simply be picked up convection given that it very rarely reaches it's physical limits. No energy has been created or lost, the system has only lost it's ability to cool an additional 2 Watts at the speed of light and instead has to cool at the speed available to convection. One more cont . . . -
papertiger at 04:30 AM on 22 August 2010Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
I think papertiger is saying that because we can observe the geology in some detail, we can infer something about the ancient climate (e.g., the existence of certain kinds of sedimentary layers suggests the presence of standing water at some point in the planet's history). Not just of the ancient climate on the Red Planet, but because of the lack of water erosion, even of the recent history, right up to the present day. Extra terrestrial astronomical forcing are the origin of all these cycles, long term (last 2.4 Ma, Pleistocene), middle term (last 127Ka, last interglacial - last glacial time-span) and short term, (the last 10.000 years (10Ka)), on both planets Earth and Mars. See comment one at the "intermediate explanation" link. -
theendisfar at 04:03 AM on 22 August 2010There's no empirical evidence
Ian, 107 continued . . . A true Greenhouse comes to mind. If it has a constant source of energy and it is perfectly sealed, then it will increase in pressure/temp until it is radiating at the same rate it is absorbing, keeping the emissivity and conductivity of the container in mind. Place the greenhouse into an atmosphere, and now you include conduction to the atmosphere at the surface. With a uniform surface and in zero gravity convection is not in play so what you'll end up with is a steady stratification of the atmosphere's temperature moving from higher temps to lower temps the farther you get from the surface. The energy in the system has not increased, we have only added an additional component with the atmosphere. The energy pressure in the greenhouse has decreased by the amount of energy transfered to the atmosphere. By adding gravity to the equation, we introduce convection. Gravity on Earth is 99% the strength at the top of the troposphere as it is at the surface so gravity will pull more strongly on cooler denser air than it will hotter cooler air that is created at and near the surface. The higher the surface temp the quicker the air near the surface heats of and the quicker it becomes less dense than the volume above it. Gravity drags cooler air to the surface which creates a larger difference in temp between it and the warmer it it replaced creating a faster rate of cooling. -
theendisfar at 03:56 AM on 22 August 2010There's no empirical evidence
Ian, from the Oregon Petition stream Also please explain to us how convection and evaporation add energy to the atmosphere. They only move the energy around Convection and Evaporation do not add any energy to any system, they only move energy from areas of high energy pressure (temp) to areas of lower energy pressures with an increasing rate with increasing differences in pressure. This is precisely the core of my argument. the enhanced green house effect is what adds the additional energy. This goes against my understanding. Once you add energy pressure to a system, it is finite and does not add more energy to the system even if a portion is trapped, the 1st and 2nd Laws apply here. Trapped radiation will only serve to slow the radiative cooling exhibited by black body radiation. My understanding is that should a method of energy transfer experience resistance, then another medium available, in this case convection combines with evaporation, will make up for this resistance in the most efficient manner possible. Preserving the 2nd Law. -
theendisfar at 02:56 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Ian et al, I was wrong to even allude that anyone was attempting to deceive another under any, or with no, motivation at all. Having attempted to be clever with my position has only secured more resentment and mistrust. Strong claims are not easily retracted, however I offer that I sincerely retract any statements alluding to the deception or understanding of anyone contributing the AGW debate. Making claims of anyone's deception without their immediate availability to offer a rebuttal or clarity is just simply wrong and I apologize to the many and most climate scientists who's motivations and contributions I surely do not fully understand. I also retract any claim or allusion that I am more well versed on this subject than anyone else. From this point forward I will only offer my understanding of the subject. You are just arguing from a baseless "I don't like it therefore it is wrong" attitude. I will offer that it is not baseless. I do not like it because my education and experiences demand, of me, a more rigorous set of methods and conclusions than what I have been exposed to. I can only offer that this paper accurately describes the scientific education I received and has been reliable to me. Making claims, to date, that are unfounded and accusations without the accused present is not worthy of discussion and upon reflection is amateur and low respectfully and arguably inclusive. I was raised and educated to be above this behavior and will seek to reinforce this claim. Also please explain to us how convection and evaporation add energy to the atmosphere. See Empirical Evidence stream for my reply. -
Peter Hogarth at 02:24 AM on 22 August 2010The Past and Future of the Greenland Ice Sheet
Berényi Péter at 01:05 AM on 21 August, 2010 You state: “However, people here are denying both air and sea surface temperatures were considerably warmer in the Arctic during the Holocene Climatic Optimum than they are today just to make the present feeble warming unprecedented and alarming” I do not think this is generally being denied, though we should quantify “considerably warmer”. The high resolution ice core data from Greenland and nearby (eg GISP2, NGRIP, Agassiz) is proxy evidence that Northern Greenland temperatures were up to 3 degrees warmer around 8000 years ago than the average for the 20th century, (your suggestion of regional variations is also validated by the evidence, eg Agassiz shows a more pronounced “Holocene Climactic Optimum”).
The Bednarski 1989 paper you cited, and many other more recent ones also provide convincing circumstantial evidence (such as driftwood deposits) that at least some of these coastal Arctic areas which are now ice bound were bounded by areas of open water for at least some periods since the last glacial. This is generally accepted and is consistent with the proxy temperature data.
The current global decadal temperature trend is upwards, and appears “amplified” in the high latitude NH. If the current or centennial trend is sustained as modeling suggests, Greenland temperatures will exceed post glacial Holocene temperatures in a relatively short timescale. The word “feeble” is perhaps inappropriate given the likely persistent nature of GHG forcing. The recent Arctic temperature rise is not unprecedented over geological timescales, but is highly significant compared to the past 2000 year proxy records (see Kaufman 2010 update and the zoomed in ice core record from Agassiz (Vinther 2009) and GISP2 (from Alley 2004 update).
It should be emphasized, that the orbital parameter forcing which is thought to have driven the gradual fall in NH temperatures since the post glacial temperature maximum is not global in effect, it is not clearly apparent in the deep sea sediment alkenone temperature proxy records for much of the rest of the globe (as is clear in Rimbu 2003) and is not apparent in the Antarctic ice core records.
The Greenland Ice Sheet mass is currently diminishing at an accelerating rate due to localized warm waters and warm currents transported from lower latitudes Hannah 2009, Di Iorio 2009, Straneo 2010, Rignot 2010 as well as recent rapidly warming Arctic air temperatures. The recent rapid change in positive forcing from increasing anthropogenic GHGs is a new factor not present in previous glaciation/deglaciation cycles. It is effectively a global effect (rather than a high latitude effect such as NH insolation) – which combines with the effects of other forcings. The oversimplistic point you make about higher relative NH insolation forcing levels in the past does not strictly hold.
Perhaps more importantly, the massive ice sheets that covered much of the NH in the last glacial period did melt (in most places completely) over the “deglaciation” time span, and we know rapid changes in temperature have been triggered by a combination of the slow change in solar forcing combined with positive feedbacks possibly from changes in the Atlantic Meridional Overturning Circulation and/or changes in GHG. This shows how sensitive our climate can be to proportionally small changes in forcing. I also do not expect the massive central Greenland ice sheet to vanish overnight, but the relatively rapid recent increased rate of loss is of legitimate concern and should not be belittled.
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John Russell at 02:08 AM on 22 August 2010What caused early 20th Century warming?
miekol at 13:27 PM on 21 August, 2010 I think I can speak for everyone who contributes to this website when I say that we share your concerns about energy availability and poverty. For me, personally, I can say that my concerns also include biodiversity loss and food availability. Please understand that we don't take any satisfaction in the fact that humans are changing the climate, complicating other issues. I really wish a magic wand could make the AGW problem disappear. I think we 'warmists' -- or whatever you want to call us -- just recognise that everything will be that much worse if the majority refuses to recognise the problem and bury their heads in the sand. To overcome the world's problems, first we must all agree what they are and how they interact. I urge you to read the links others have provided and understand the science for yourself. The facts will speak for themselves -- provided you're willing to be open and objective. From the way you end your last comment I think you are. -
MichaelM at 02:05 AM on 22 August 2010Is the sun causing global warming?
As it says at the top of the page "This post is the Basic version (written by John Russell) of the skeptic argument 'It's the sun'" The comments at that page number over 550 covering a period of 3 years. Is this page, and indeed the other Basic versions not in danger of rehashing old points? I mention this as the chances are that the points Kamilian brings up here and at other Basic pages may have been covered over the last few years at the relevant main page. Is the intention to have Basic, Intermediate, Advanced share the same set of comments or will each have their own? I've seen moderators note things as being Off-Topic so should they note things as being Off-Level? -
nealjking at 01:56 AM on 22 August 2010Communicating climate science in plain English
- I think tabs make more sense than a slider: Discrete choices vs. a continuous range. - However, I think the choices should be: 1) The one-liner 2) The "basic" explanation 3) The "in-depth" explanation I think it's going to be hard to do a really good job on the previously discussed "advanced" explanation, because you're really talking about an expert's level of understanding re-packaged in layman's language. The most I would do for this site is to find pointers to appropriate existing discussions (if any). So this should be a 4th tab, but mostly with pointers. - With respect to writing style: 1) One-liner: From what I've seen of the examples, they look about right. 2) "Basic" explanation: Should really aim for an 8th-grade level of language use. I think this is about what writers aim for in documentation that they really need people to understand. As I've remarked elsewhere, this doesn't mean the argument is "dumbed down", just that the style is trimmed and the vocabulary not too extensive. 3) "In-depth": I think the current level of writing is about right. 4) Pointers to advanced presentation: Same level as 3). - Just one more comment on the importance and dignity of explanation at the audience's level: The great experimental nuclear physicist Ernest Rutherford once remarked: "If you can't explain to a barmaid what you're doing, you don't understand it!" -
CBW at 01:44 AM on 22 August 2010Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
I think papertiger is saying that because we can observe the geology in some detail, we can infer something about the ancient climate (e.g., the existence of certain kinds of sedimentary layers suggests the presence of standing water at some point in the planet's history). But, no, we don't know much about climatic trends in the last century. But even if we did, it wouldn't tell us much -- that's the point of the article. We can directly measure solar output and we can measure how much of it is reaching the Earth. Using Mars as a proxy would introduce huge amounts of uncertainty under the best of circumstances, and we have anything but the best of circumstances with respect to our understanding of Mars' climate. gpwayne, John -- I think each of these short explanations should end with a sentence like: "If you'd like to know more, see our intermediate explanation." Where "intermediate explanation" is a link to the more detailed entry. -
Ian Forrester at 01:28 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar said:Calling someone a liar could be considered ad hominem
Wrong. Calling someone a liar who has obviously just told a porkie is not an ad hominem attack just a reflection of the truth. As far as I am aware the only proven liars are all on the side of the deniers: Monckton, Singer, Michaels, Lindzen et al. If you have proof of climate scientists lying then please provide evidence otherwise you are the one guilty of an ad hominem attack. You are just arguing from a baseless "I don't like it therefore it is wrong" attitude. Also please explain to us how convection and evaporation add energy to the atmosphere. They only move the energy around, the enhanced green house effect is what adds the additional energy. Please read some simple physics texts. -
Peter Hogarth at 01:18 AM on 22 August 2010The Past and Future of the Greenland Ice Sheet
Berényi Péter at 09:21 AM on 20 August, 2010 “SST was more than 2°C above its present value for several thousand years with no adverse effect on the Greenland ice sheet” The second part of this statement is doubtful. One of the points of this post is that there is plenty of evidence and peer reviewed research which shows that the Greenland Ice Sheet volume has varied in step with the NH high latitude temperature variations in the past, see Vinther 2009. Areas at the ice margins may have completely melted over periods as short as decades (Alley 2010 cited above). -
kamilian at 01:10 AM on 22 August 2010How climate skeptics misunderstand past climate change
Perhaps you may like to illustrate how this blog, and climate science in general, doesn't seem to understand past climate change. This site suggests that warming starts in the SH, is amplified by greenhouse gases and other positive feedbacks, and greenhouse gases transport this to the NH. 1) Richard Alley (at ~38m) suggests the "physically realistic" models show reduced summer sun causes ice sheets to grow in Canada eventually leading to a globally average reduction of ~5-6 °C, yet this page contains Vostok ice core data suggesting temperature falls before CO2 does. If the change starts in the NH, how does CO2 still lag temperature (during these cooling periods) in the SH if CO2 has such a significant effect, particularly in transporting heat from one hemisphere to the other? 2) This page suggests charts provided by Ned (located here), which don't appear to bear any relevance to climate science, are a good example of how positive feedbacks don't lead to a runaway climate. Looking at the Vostok data here: a. How do you explain the almost linear temperature rise in the three warming periods at ~125,000, ~240,000, and ~325,000 years BP? If positive feedbacks don't lead to a runaway climate they need to illustrate asymptotic behaviour, which the empirical evidence doesn't support. b. In the most recent warming (~20,000 years BP), where in the EPICA Dome C data (which is what I look at, but it's seems to also be visible in the Vostok data) there's warming for a few thousand years, then cooling for about 1,500 years, then warming again for about 1,000 years. If positive feedbacks are so strong, how do you explain such (relatively) rapid changes in gradient (as they're significant, rather than being almost zero)? c. How do you explain the significant (~10-15 %) drop in CO2 around ~325,000 years BP with no corresponding change in temperature? In response to Dappledwater (Comment #28) and the Moderator Response, thank you for illustrating what seems to me as the biggest issue with this ice core data, the correlation between temperature and numerous variables that apparently cause the change. Hansen et al. 2008 Figures S18 and S19 illustrate the strong correlation between temperature and CO2, CH4, and surface albedo. Page 2 attributes the change in temperature between the LGM and pre-industrial Holocene to a radiative forcing of ~6.5 W/m^2 with ~54 % surface albedo, ~35 % CO2, ~6 % CH4, and ~5 % N2O. We also know that warmer climates lead to less snow and ice as well as cause vegetation changes, which are changes in surface albedo, and warmer climates also lead to greater concentrations of CO2 due to out-gassing. In other words, temperature has some influence over at least two of the supposed forcings. My reasoning is along these lines. If the data showed perfect correlation between these variables, then the only possible explanation is that changes in temperature caused all the other changes and they had no influence on temperature (as climate science suggests there are external forcings of temperature such as solar variability, orbital effects, etc.). In reality there's strong correlation (particularly between the LGM and pre-industrial Holocene) suggesting that change in one variable (independent) is the significant cause of change in the other variables (dependent), since external forcings only directly influence temperature it's unlikely to be a common cause for all variables. It also suggests that changes in any of the dependent variables would have little if any influence on the independent variable. There's a couple of things that suggest temperature would be the independent variable: 1) Temperature is directly influenced by external forcings. 2) The relationship describing the correlation doesn't correspond to the forcing (e.g. the trendline for CO2 appears to be a quadratic which is contrary to the logarithmic relationship provided by climate science). I'm not worried about the lag between temperature and CO2, how do you explain the strong correlation between all these variables if there are multiple drivers of climate which would tend to break the correlation? -
kamilian at 01:07 AM on 22 August 2010What caused early 20th Century warming?
Please refer to this comment as it's relevant here as well. In response to Dappledwater (Comment #14), perhaps you may like to do your own investigations, the page you linked to here is misleading at best, and just plain wrong in some cases. First, Figure 2 combined with the paragraph preceding it suggests it shows the measured change in outgoing radiation, which it doesn't, it shows the simulated change. You can see this here which quite clearly labels that same graph as simulated. It also shows that in Figure 1b) the middle graph offset -5 K (simulated) shows a reduction in the CO2 band (~540-800 cm^-1) up to ~740-750 cm^-1 while the graph above it (observed) doesn't show any change. It also refers to the Griggs 2004 paper which appears to be available here as well. Figure 2 in that paper again clearly shows little if any change measured in the CO2 band with the simulated results suggesting there should be a drop between ~700-740 cm^-1. Also, there's a measured increase in the CH4 band between 1997 and 2003, which the authors do not provide an adequate explanation for, and conclude that the simulations (which are meant to be based in physics) require more work as they were unable to predict the change. Secondly, Figure 3 has this description before it: When greenhouse gases absorb infrared radiation, the energy heats the atmosphere which in turn re-radiates infrared radiation in all directions. Some makes its way back to the earth's surface. Hence we expect to find more infrared radiation heading downwards. Surface measurements from 1973 to 2008 find an increasing trend of infrared radiation returning to earth (Wang 2009). A regional study over the central Alps found that downward infrared radiation is increasing due to the enhanced greenhouse effect (Philipona 2004). Taking this a step further, an analysis of high resolution spectral data allowed scientists to quantitatively attribute the increase in downward radiation to each of several greenhouse gases (Evans 2006). Which misleadingly suggests that Figure 3 illustrates the change in downward radiation, even though Figure 3 is correctly labelled. I would have thought it was more important to explain how the Evans paper can conclude that a measured/calculated change of 3.52 W/m^2 "compares favourably" with a simulated change of 2.55 W/m^2. On what planet (with or without a greenhouse effect) is a ~27 % error considered to compare favourably? Another important issue that description raises is a qualitative idea floating around this site about how a tropospheric hotspot is not a signature of an enhanced greenhouse effect (it would be caused by any warming at the surface), apparently it's the warming troposphere and cooling stratosphere due to more energy being "trapped" in the troposphere. Climate science says that the stratospheric cooling is due to increased greenhouse gases in the stratosphere having a net cooling effect, suggesting there would also be additional greenhouse gases in the upper troposphere. As that description suggests, greenhouse gases absorb radiation, become warmer, and then emit more radiation. If the tropospheric hotspot is not a signature of an enhanced greenhouse effect, it suggests that the additional greenhouse gases in the upper troposphere are not absorbing any significant radiation (from any direction), otherwise it would be a signature in it's own right. This leads to: 1) If this region is not absorbing any additional radiation to any degree, then no radiation can be passing through this region (from any direction) that could be absorbed by greenhouse gases, otherwise the additional greenhouse gases would absorb the radiation and become warmer than if there was some other cause of surface warming. How is it be possible for less radiation at greenhouse gas wavelengths above the tropopause that originated from below the tropopause if the upper troposphere is not absorbing any radiation to any significant degree? 2) If everything below the tropopause is getting warmer and emitting more radiation at all relevant wavelengths, and the stratosphere is cooling as it can emit more radiation at greenhouse gas wavelengths, why would there be less radiation reaching space? This leads to another explanation often given, that adding greenhouse gases increases the "optical thickness", leading to radiation being emitted from a higher altitude which is cooler. The problem here is I'm yet to find one that provides a quantitative approach and include tropospheric warming. Explaining this more completely, at pre-industrial times the radiation was emitted at a height h1 at temperature t1, and there was another height h2 at temperature t2. Between then and now greenhouse gases were added and the temperatures increased, increasing temperature t1 to t1' and increasing temperature t2 to t2', also changing the emission height from h1 to h2. The question that doesn't seem to be properly addressed is if t2' is less than t1, as opposed to the explanation given that t2' is less than t1'. -
kamilian at 00:55 AM on 22 August 2010Is the sun causing global warming?
So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming. No credible science? So you're suggesting that this site isn't about credible science? Seeing as this page quite clearly states: The other consequence of the warming ocean is it means there is additional "warming in the pipeline". Even if CO2 emissions were to start falling now, we already face further global warming of about another half degree by the end of the 21st century (Meehl 2005). So even if the forcing was reduced, there'd be warming for potentially 90 years. Considering this page suggests that the temperature in the graph on this page also corresponds closely to SSTs, then the cooling trend around 1940-1950 doesn't correspond to the increasing solar activity. Seeing as the temperature fell or remained stable while solar activity increased between 1940 and 1960, and a reduction in CO2 now would see continued warming, it suggests that temperature doesn't directly correlate (temporally) to the forcing. It seems far more likely that the increase in solar activity of ~0.8 W/m^2 up to 1960 in that graph is the cause of recent temperature changes rather than the CO2 change since 1960 of 5.35*ln(390/317) = ~1.1 W/m^2 (i.e. they're of similar magnitude) due to the thermal inertia of the system. Perhaps you would also like to put things in perspective. From 1880 there's been a minimum ~0.5 W/m^2 increase in solar activity (~0.8 W/m^2 until 1960, then a decrease). In the same time there's been a change in CO2 of 5.35*ln(390/290) = ~1.6 W/m^2. According to the IPCC there was a change in CO2 between 1750 and 2005 of ~1.7 W/m^2 and a net change in anthropogenic forcing of ~1.6 W/m^2. How can solar variability be completely discounted, since the graph here suggests it's at least ~30 % of the change due to anthropogenic sources? How do you explain why the IPCC graph suggests ~0.1 W/m^2 due to solar irradiance when this graph suggests otherwise? Perhaps the IPCC doesn't consider it cherry picking, but ~0.1 W/m^2 doesn't show the full story even if it is an accurate delta between 1750 and 2005. Furthermore, what known physical properties of greenhouse gases are you referring to? When I think of physical properties, I think of this as an example. We see that the Stefan-Boltzman constant is considered to be known to a standard uncertainty of 4e-13 W/m^2 and relative standard uncertainty of 7e-6 (68 % confidence interval). For two standard deviations (95 % confidence interval) it would be an uncertainty of 8e-13 W/m^2 and relative uncertainty of 1.4e-5. I would have thought that the effect of CO2 is pretty important in climate science, Section 6.3.1 of this document says: IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included. So it used to be 4.37 W/m^2, which was revised to between 3.5 and 4.1 W/m^2, leading to the current 3.7 W/m^2, all of which are estimates as opposed to physical properties. These estimates have an uncertainty of 0.2 W/m^2 and relative uncertainty of 0.05 (with no mention of confidence interval). Interestingly, IPCC AR4 WG1 Section 2.3.1 suggests 3.7 W/m^2 +/- 10 % for a 90 % confidence interval, giving an uncertainty of 0.37 W/m^2 and relative uncertainty of 0.1, which could be considered worse than the TAR! I don't think they really compare as physical properties, and don't see how they can be considered to be known when they're estimated. -
theendisfar at 00:45 AM on 22 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
KR, First, regarding the 'CO2 is not the only driver' post, it seemed as though the replies were stuck at 250, my posts were not showing up, I thought the post had closed so I abandoned the effort. I see that it is not closed so I'll pick it back up, I have more to add. This is about our futures, our descendents futures. (Moderator, this is not an attempt to inject my beliefs, just motivation) Precisely, without knowing whether an afterlife is reality, I believe my best chance at immortality is to raise children who can take care of themselves to better raise children who can do the same. The better job I do, the better the chances that what my parents, mentors, and experiences have taught me will live on and be expanded. Not as fancy other's beliefs, but it's the best I can come with and it seems a worthwhile effort. It is truly in my best interest that a healthy environment exists for as long as possible. We want the same things in that regard. If you have actual issues with the data or the conclusions drawn from them, we can talk about it. I welcome the offer and hope to make it worthwhile for you and SS as well. Looking back over some posts I recognize that we and others have traded many jabs, it is obvious you and others are learned in this subject and I would not be interested in discussing this if you all were not. With that, I believe that the confirmation or falsification of AGW can be achieved within a year if subjective influences are put aside. I recognize that many here do not share my position that AGW has not been confirmed, or falsified for that matter, and this presents additional challenges, but I'll do my best to earn your patience. -
Philippe Chantreau at 00:43 AM on 22 August 2010Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
So let me get this straight papertiger: you are arguing that the statement that we don't have historical data on Mars prior to the 70's is not true because an orbiter has been observing since 2006? Makes sense... -
Daniel Bailey at 23:34 PM on 21 August 2010The main culprit in mid-century cooling
Tamino over at Open Mind has a nice post showing just when (1975) the warming "resumes" (pollution controls kick in, allowing the true warming signal to no longer be masked/inhibited by the aerosol cooling effect). The CO2 concentration/temperature climb continues unabated to this day. Good post, Anne-Marie The Yooper -
nealjking at 23:08 PM on 21 August 2010Plain English climate science - now live at Skeptical Science
First: I applaud the effort to boil down the arguments to the basic gist: People can always find more detail in the intermediate-level discussion. However: My impression is that even the basic-level discussions are written at an advanced-undergraduate level of English. If you want to get through to the majority of American readers, I think something more like 8th-grade level is called for. It doesn't mean that the argument needs to be "dumbed down", but that the manner of expression should be a little plainer, and the range of vocabulary should be cut back. I hope this makes sense to you. Best regards! -
Eric (skeptic) at 22:28 PM on 21 August 2010How climate skeptics misunderstand past climate change
CB, that's hardly a fair comment (no effort), I looked up C-C and found the reason you quoted it and KR assumes constant RH. I believe that Soden and Held are oversimplifying by using C-C globally. I don't disagree that a warmer world has more water vapor in the air, my question at beginning of the thread was when does the positive feedback stop. Your answer was two-fold: never (22) and use the math (37) which I answered in 38. It may interest you and others to know that there were number of days here in the DC area this summer where our humidity was higher than Miami including total precipitable water. Also his year we had many days that were warmer than Miami where it never got above 95 (we were above 100 several times). Here's our plot: http://www.erh.noaa.gov/er/lwx/climate/cliplot/KDCA2010plot-2.png and theirs: http://www.srh.noaa.gov/mfl/?n=cliplot -
Rob Painting at 21:19 PM on 21 August 2010The Past and Future of the Greenland Ice Sheet
BP, the Stott graph shows SST cooling from 11 to 10 kyr BP onwards, whereas the Greenland ice core record has a thermal optimum between 8 to 6 kyr BP.
There is also evidence of the Northern coast of Greenland being free of sea ice between 8.5 to 6 kyr BP. See here beach ridges, striated boulders & marine sediment
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CBDunkerson at 21:03 PM on 21 August 2010How climate skeptics misunderstand past climate change
Eric, as I have explained before, and KR and johnd both just did again, the REASON there is more precipitation in a warmer world is that there is more water vapor in the air to precipitate out... because more heat causes more evaporation which puts that water vapor into the air. As you seem to insist on adhering to beliefs which are clearly false without making any effort to examine the proof to the contrary presented to you I don't see much point in continuing this. You should head to Miami and enjoy the ultra low humidity your logic indicates exists there. -
MichaelM at 21:02 PM on 21 August 2010Waste heat vs greenhouse warming
The slope doesn't flatten out as the slope changes with the height of the sun in the sky i.e. the amount of energy a plate on the lunar surface receives is directly proportional to the angle of the sun. The graph in fig 2 is that dome shape, with the initial near-infinite slope, because it is at the equator. As you move north or south the shape changes away from a dome towards a flatter sine wave as the sun rises more gently above the horizon. This image shows the paths of the sun at a latitude of roughly 50deg north (actually from Bristol in the UK) over a period of months. The closer to the poles the flatter the slopes, the limit being the axis not being perpendicular to the sun. -
scaddenp at 20:56 PM on 21 August 2010Can't We At Least Agree That There Is No Consensus?
Poptech - what impact indices measure is the no. of times papers are cited by other journals, not just the E&E echo chamber. While E&E is not about tobacco (hence the quote marks) it certainly appears to be used by those following tobacco industry tactics. I would say the impact of papers in E&E to science is approximately zero and nothing you claim can change that. On the whole, scientists dont share the denialist problems in discerning good from bad. -
Berényi Péter at 20:52 PM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
"How many cats' tails would it take to reach the sky?" "Just one if it's long enough!" -
scaddenp at 20:45 PM on 21 August 2010What caused early 20th Century warming?
Michael, well please do work on the matter provided. Disbelieving something because it is inconvenient might be human nature but not rational, and in this case downright dangerous. Reality is not necessarily arranged for our benefit and the laws of physics do not bend to our wishes. That said, I think you are way too pessimistic and falling for disinformation spread by those who most certainly would be adversely affected. Try having a look at MacKay's Sustainable Energy without the hot air. He doesnt pull too many punches about the problems (often criticised as being pro-nuclear but MacKay counters that he is pro-arithmetic) but hardly condemns the world to energy-poverty either. Regards, Phil -
RSVP at 19:16 PM on 21 August 2010Waste heat vs greenhouse warming
MichaelIM 234 You are correct, "Hours" in the caption refers to Moon hours which means 29.5 hours per notch. Things dont warm so fast apparently so it looks like I am wrong. In any event, Fig 2 is still very intersting as it shows heating has a nearly infinite slope coming out of the Lunar "night", without the presence of GHGs. :) Obviously on an expanded time scale, it would be seen to leaning, but it is intersting to see this is no sine wave and that it can only get so cold. (cold enough for me) Is there an explanation for why the high doesnt flatten out like the low on both Mercury and the Moon? As a hard core skeptic, its hard to believe the rotational cycle just happens to coincide to give perfect dome shaped profiles. Dont worry, if you arent sure, I will read the article in my spare time. -
John Russell at 18:05 PM on 21 August 2010Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
The quote you use starts; "We have virtually no historical data about the climate of Mars prior to the 1970s..." (my emphasis). So it is true. And 4.5 years is not long enough to gather any meaningful data about climate on Mars (particularly as I assume you mean Earth years). But thanks for the interesting info about HiRISE. -
RSVP at 17:11 PM on 21 August 2010What were climate scientists predicting in the 1970s?
Marcus 27 You got me very wrong including my insertion there about hubris. We could turn the whole thing around however and perhaps even veer towards the correct "topic". That would be a question like, "could man provoke an ice age?". Supposely all those sulfur based aerosols helped cooling, not to mention what all that nuclear testing did. All these questions seem very difficult and who knows, maybe we were going into an ice age until we "fixed" one problem to only get another. I have a hard time not seeing hubris as a big stumbing block, but I think you did not understand the remark. It is not to say we cant mess up the entire planet, we can, and we are doing this just fine. The hubris has to do with wanting to believe we have all the answers, when in reality the problem is much more complex than we think. -
Doug Bostrom at 16:35 PM on 21 August 2010NASA-GISS: July 2010-- What global warming looks like
"AGW proponents." Comical. Some remarks about Pakistan by Dr. Ricky Rood here. -
RSVP at 15:55 PM on 21 August 2010What were climate scientists predicting in the 1970s?
JMurphy 22 There is no such thing as "the science", however it is good to be aware that some people think that way. Thanks for the warning. -
johnd at 15:55 PM on 21 August 2010What caused early 20th Century warming?
adelady at 14:24 PM, there is almost always a drought somewhere in Australia. With various indicators such as the IOD and IPO seemingly taking 6 or 7 decades to cycle through both phases, it is impossible to determine any trends before any cycle has completed fully. The Queensland National Resources and Mines put out a chart depicting the rainfall across all of Australia for each year beginning 1890. Such a chart makes it easy to see the "flow" as the dry and wet years are cycled through and as the distribution varies across the regions, something that is not always evident looking at graphs.
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