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Tom Curtis at 14:47 PM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Anthony C @57: 1) If you add sufficient absorbers of high energy radiation to the upper atmosphere, the result will be a reverse greenhouse effect in which a warm upper atmosphere results in a surface cooler than 255 degrees K. It would be very difficult, however, to bring about that situation on Earth. Titan actually experiences this effect, but is the only body in the solar system known to do so SFAIK.
2) Yes, as the blip in the center does show increased emissions with increased CO2 concentrations because its effective altitude of radiation rises higher into the stratosphere. The effect in real life is not as strong as shown on Modtran because:
a) Increased CO2 levels cool the stratosphere, counteracting the effect; and
b) Increased CO2 levels cause the tropopause (the boundary between the troposphere and stratosphere) to rise, thereby increasing the altitude to which the lapse rate continues as in the troposphere.
Because Modtran uses standard temperature profiles which do not adjust with changes of forcing, it cannot show these effects. However, they will show up in Global Circulation Models (GCM) and are therefore accounted for. Whether this aspect in GCMs is robust, or an area of uncertainty I could not say.
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Alex C at 14:38 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
If I could reword a previous statement: "It's not legitimate to compare scenarios to the real world result just because they share the same name or are labeled "best."" to: "It's not legitimate to compare scenarios to the real world result just because they are called "BAU" or "best."" -
Rob Painting at 14:37 PM on 3 March 2012Trenberth can't account for the lack of warming
Desertphile - see the advanced version of this rebuttal. The global energy imbalance observed in Loeb (2012) is 0.5 (±0.43) W/m2. Don't know where you get your information from, but it is not correct. -
Alex C at 14:36 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Update to my previous: yes, 6.3 was the scaling factor, from Hansen et al 1988. This can be found in Table 2.2 below: http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_chapter_02.pdf -
wingding at 14:33 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Anteros: Business As Usual did not happen. The Montreal Protocol significantly reduced CFC greenhouse gas emissions and methane rise slowed down to a stop. -
Alex C at 14:33 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
If I recall correctly too, the forcing/concentration relationship for CO2 was higher during AR1 than for subsequent reports (later reports adopted the ∆F = 5.35ln(C/C0) equation developed in Myhre et al 1998, and that is still used today). The old scaling factor was closer to 6.3(?) I think, so any predicted increase in CO2, and likely other GHGs for that matter, would have resulted in an estimate of radiative forcing that was higher than the actual forcing, thus a higher prediction of temperature. The point made in #2 in the post above is a very important one. It's not legitimate to compare scenarios to the real world result just because they share the same name or are labeled "best." -
Tom Curtis at 14:24 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Anteros @ 10: 1) You have egregiously misquoted the IPCC FAR. The actual text from the quoted section reads as follows:"Based on current model results, we predict: • under the IPCC Business-as-Usual (Scenario A) emissions of greenhouse gases, a rate of increase of global mean temperature during the next century of about 0.3°C per decade (with an uncertainty range of 0.2°C to 0.5°C per decade), this is greater than that seen over the past 10,000 years. This will result in a likely increase in global mean temperature of about 1°C above the present value by 2025 and 3oC before the end of the next century The rise will not be steady because of the influence of other factors. • under the other IPCC emission scenarios which assume progressively increasing levels of controls rates of increase in global mean temperature of about 0.2°C per decade (Scenario B), just above 0.1°C per decade (Scenario C) and about 0.1 °C per decade (Scenario D)"
(Periods where left out of the PDF, and have been reinserted by me in what I believe to be the appropriate positions.) Clearly, the IPCC FAR prediction is relative to different possible forcing scenarios. It does not, as you misrepresent it as doing, make an absolute prediction independent of future concentrations of GHG in the atmosphere. That also means there is no justification for comparing their "prediction" to observations without first determining how GHG forcings actually changes over time, and which of scenarios A, B, C and D best describe that change. 2) The central prediction for BAU of 3 degrees C is less than that in graph B. In other words, the IPCC FAR prediction assumes a climate sensitivity of less than 2.5 degrees C per doubling of CO2. There is therefore no possible justification for using the high climate sensitivity from Graph A, and even using the Graph B (Best Estimate) predictions will overstate the predictions made in the summary for policy makers. 3) The prediction quoted by you is for the trend per decade averaged over the full century. It is common knowledge, and can be verified by laying a straight line against the graph that temperature changes are expected to be more rapid at the end of the century than at the beginning. Therefore using the prediction of average full century trends necessarily overstates the predicted trend for the first two decades of the 21st century. Given that, there can be no justification for using the full century trend predictions for determining the IPCC FAR predictions under different scenarios for the first 20 years after the prediction. Rather, you must determine the prediction over those decades seperately as was done above. To summarize, there is no merit to your accusations which are based on misrepresentation, misquotation and flawed analysis at best. -
Alex C at 14:22 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Anteros @10: The average rate of temperature change would have been 0.32˚C/decade, but that does not mean that each decade would see a 0.32˚C increase. The change over 1990-2010 was not 0.64˚C in the BAU scenario, it was closer to 0.5˚C. -
Muzz at 14:15 PM on 3 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
As all the evidence points to an ever increasing amount of industrial CO2 emissions it would be handy if someone would quantify the damaging consequences of these emissions -
Anthony C at 14:10 PM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Questions on this post 1) What would happen if you put more absorbers of high energy radiation (sunlight) and warmed the upper atmosphere, since it is no longer as cold? More generally how can you change the vertical temperature rate of decline to change the greenhouse effect? 2) In the MODTRAN model, adding more and more CO2 increases the emission to space right at 667 cm^-1 (the blip that continues to go upwards, all the more at very high concentrations. Is this accounted for since it seems to reduce the CO2 effect? -
Anteros at 14:08 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Apologies for using capitals. I'll re-write in lower case letters the fundamental prediction of the FAR. "Based on current model results, We predict: An average rate of increase of global mean temperature during the next century of 0.3C per decade (with an uncertainty range of 0.2-0.5C per decade)" Dana1981 @ 7 You say that climate predictions are wrong usually either because the climate sensitivity is too high or because the emissions scenarios were not perfect. There isn't very much else to get wrong is there? But I think you do most sceptics a disservice by saying they are not interested in why predictions are wrong. I don't think that's true. But I think what is crucial, before beginning to understand why the predictions were wrong, is to actually admit the fact that they are wrong in the first place. -
Fairoakien at 14:07 PM on 3 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
The cost of global warming are stated as being very specific , but it is agreed that the costs are ambiguous. What are the costs to canada if the climate becomes warmer and farming opens up in larger areas. Those studies estimating costs of GW assume all changes are negative. What about vineyards opening in Northern germany. Or, contrary to this years winter, if the northern tier Euro countries can have longer growing periods. So its the studies that estimate costs of GW that are skewed, always assuming the effects are negative. -
owl905 at 13:45 PM on 3 March 2012The Independence of Global Warming on Residence Time of CO2
Dikran wrote:- "owl905 The fact that CO2 levels had been pretty stable between 180ppm and 300ppm for the last 400,000,000 years, even during glaciations, is a pretty good indication that a balancing process exists." Simply untrue. That oscillation is a reflection of the CO2 load, and the biosphere context during some of the recent cycles. The claim of an intervening set of forces to return it to a previous state (after the GHG proportions are changed, the oceans warmed, and the biosphere disrupted) is nothing more than wishful fantasy. It ignores the geological record of different patterns in different ages. While not trying to be abrasive, you're trying to work both sides of the street arguing in favour a return to natural levels in a useful period of time while confusing this by discussing multiple millenniums. Frankly, stating that "the carbon cycle does re-establish the equilibrium" is refuted by the track record - episodes of massive GHG injections into the biosphere have upset things for very long periods - the Permian, the KT, and the PET juncture. The 400k record isn't even the major story - the record shows much longer interglacials before that time - so your 'natural balance' claim consists of 3 out of the last 8 or more inter-glacials. The geology record shows no period where GHG levels fell 40% in less than a century. Additionally, your remark to MHauber that the missing CO2 accounting is virtual proof of a mystery sink is far beyond what the accounting, the chaotic nature of the pollution, or the science, supports. And that ocean 'carbon sink' is so poor, ocean acidification has become one of the great pollution problems. That's exactly why suggestion of oceanic sequestering of a decade ago went to the trash heap. -
Anteros at 13:15 PM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
I'm a little disappointed that you didn't actually address any of my criticisms from the Realclimate thread. This is somewhat ironic, because one of my criticisms is that SkS didn't address the predictions of the FAR. I use "predictions" because that is what the FAR used, although it is nowhere in your original article. You do not even mention what the fundamental FAR predictions given to policymakers of the world was, which was this: "BASED ON CURRENT MODEL RESULTS, WE PREDICT: AN AVERAGE RATE OF INCREASE OF GLOBAL MEAN TEMPERATURE DURING THE NEXT CENTURY OF 0.3C PER DECADE (WITH AN UNCERTAINTY RANGE OF 0.2-0.5C). That 0.3C [Which they specified would lead to 2C above pre-industrial by 2025] was with a BAU emissions scenario which they told the leaders of the world (and on which the UNFCCC 1992 was signed) would occur "if few or no steps are taken to limit GHG emissions." The upper and lower uncertainty limits were, of course, model results from runs with 1.5 and 4.5 degC/2xCo2. Now, my point was that you never mentionedANYof this in your article. You never mentioned the word "prediction" once. On the Realclimate thread Professor Barry Bickmore called the predictions "way off" and Gavin said they were "wrong". My comment on the thread was to agree with them and contrast this to your praise for their accuracy. Finally, in your post above, you say of the graph in the WSJ article - "This line shows a temperature increase of 0.32°C per decade, far outside of most climate projections. Far outside most of most climate projections? This is simply not true - the 0.3 degrees which the graph represents isEXACTLYthe central prediction of the whole 1990 IPCC FAR. It is the headline number and one that was impressed upon every leader of every country in the world. Perhaps many of your readers were too young to remember. Please do not mistake me for someone who has any gripe against the IPCC. The prediction that was "way off" was made in good faith and of course we are learning all the time. However, it is impossible to learn from a prediction that is "way off" unless it is admitted that the prediction was badly wrong in the first place.Response:[DB] Please take the time to acquaint yourself with this site's Comments Policy. Note especially the section barring the use of All-Caps, such as you have done here. Future comments constructed thusly will be deleted or snipped at the moderator's discretion.
All-Caps portion struck out.
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Todd F at 09:39 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Thanks Dana for pointing me in the right direction. I found the article about the growth of sulphur emissions in East Asia to be interesting. I hadn't realized that sulphur emissions in that region would have more than the normal effect. In my toy climate model, I haven't been projecting much [negative] increase in the rf for aerosols (past 2000), due to stabilizing global sulphur emissions. It appears that GISS thinks that the net radiative impact for aerosols is still growing in influence, even though it seems that global sulphur emissions are declining somewhat. If sulphur emissions continue to grow in East Asia, it may continue to mask much of the radiative impact of GHGs for some time ahead. But, due to higher climate sensitivity than previously assumed, this is going to end up spelling much higher growth of global temperatures later in the century. This is also problematic in that it may delay the perceived urgency of addressing the problem. -
Tom Curtis at 09:22 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
ribwoods @54 and 55, thankyou for picking up on my error. Of course, I know this backwards, so I am at a loss to explain how I got it backwards when writing that comment, other than that it underlines the need for me to proof read my comments. I have corrected the original with due acknowledgement. -
Composer99 at 08:24 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Climate pseudoskeptics also have no problem appealing to models if they think the model results will agree with them (e.g. Spencer's simple model which Barry Brickmore has critiqued on several occasions). -
dana1981 at 08:01 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Mammal_E - indeed, all the denialists get out of any model prediction or projection is "the model is wrong." This includes "skeptics" like John Christy, coincidentally. They never seem interested in examining why the model projections were "wrong", which is usually either because the model sensitivity was high (as in Hansen 1988) and/or because the emissions scenarios were not perfect. -
dana1981 at 07:57 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Todd F - no, the FAR did not account for aerosols. See the link provided by mdenison in comment #1 for details. As that post discusses, accounting for aerosols would reduce the net forcing, which would thus suggest the actual climate sensitivity is somewhat larger than 2.5°C for 2xCO2 (as sensitivity = dT/dF). -
Mammal_E at 07:50 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
"Skeptics" sometimes jump on this sort of thing as equivalent to cherry picking, in that you've fed the observed (known in hindsight) values of model inputs into the original model to yield new predictions or select which predictions to consider. However, this exercise actually confirms the validity of the conceptual understanding that the model embodies, because the structure of a model and the particular values of its inputs are completely separate things. Consider: I my conceptual understanding of accounting is embodied by this model of the growth rate of my bank account: rate of balance increase = salary - expenses + interest - fees Based on this model, I predict that if my salary increases by $100 per month and everything else stays the same, my bank account balance will increase by $100 per month. (Note: this prediction is not the same as saying that my bank account is ONLY affected by salary and not at all by interest, fees, or expenses). Now, suppose that my salary actually increased by $80 per month and the bank added a new fee of $10 per month, so that my bank account only grows by $70 per month. Does this discrepancy between predicted and realized rates of increase invalidate the model, or my conceptual understanding of the system? NO! The only thing it indicates is that predictions about future changes in model input values were not quite right right. The conceptual understanding is intact, because when I use the observed input values, the model accurately predicts the observed change in the state variable. -
ribwoods at 07:10 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
(continuing my preceding comment) The most logical correction is probably to interchange "escaping to space" and "entering the system" wherever they appear. This reversal doesn't seem to have affected any subsequent argument. skept.fr @38 seems not to have noticed, and writes as though your statement in #36 were corrected to the proper sense. -
Todd F at 07:07 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
Good post. Is there any indication that FAR took account of aerosols? I see from your source where the actual forcing was +0.63W/m^2, but the source doesn't include the impact of aerosols. NASA has its estimates in below link. The 1990-2010 impact of aerosols (tropospheric+stratospheric+Black Carbon+Aerosol indirect effect), is -0.38 W/m^2 for 1990-2010, which offsets their estimate of GHGs, which they calculated at +0.71 W/m^2. That nets out to +0.33 W/m^2. Could also add in snow albedo at +0.05 W/m^2 and solar at -0.12 W/m^2. Given that, one might expect even less warming than you calculated assuming +0.63W/m^2. http://data.giss.nasa.gov/modelforce/RadF.txt -
ribwoods at 06:50 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Tom Curtis @36: "The most fundamental fact about the greenhouse effect is that if the energy escaping to space exceeds the energy entering the system, then the temperature will rise until they balance again. If the energy escaping is less than the energy entering system, temperatures will fall until they balance again." Don't you have the two cases backwards there? If energy escaping exceeds energy entering, the temperature will fall, not rise. -
Chris G at 05:40 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
The take-away that I took from that RC thread was that Anteros is trying to assert that the IPCC did not know what they were talking in 1990 about because they were not able predict the future GHG emissions with high accuracy. -
Michele at 05:39 AM on 3 March 2012Radiative Balance, Feedback, and Runaway Warming
@ Jose_X #68 I try to give some answers. 1) Atmosphere 100%N2 The atmosphere is perfectly transparent and so isothermal: that’s, Ts = Tt = Tef where ‘s’ is surface, ‘t’ is TOA and ‘ef’ is effective. 2)Let’s add CO2 as 300 ppm as for Earth The balance of radiative power is (missing the constants) xTt^4 + (1-x)Ts^4 = Tef^4 Tt/Ts = (Pt/Ps)^(R/Cp) Ht = (Ts-Tt)Cp/g where ‘x’ is the % of radiation in the CO2 bandwidth, ‘(1-x)’ the remaining radiation in all the spectrum, ‘P’, ‘R’, ‘Cp’ are well known by thermodynamics, ‘Ht’ is the eighth above the ground where P = 0.2 bar, ‘g’ is the gravity. The troposphere, cooled at the top and warmed at the bottom, becomes adiatically convective. Given x, the system is closed. If x << 1, then is Ts = (1+x/4)Tef, Tt/Ts = (0.2/90)^(299/1043) = 0.287, Ht = (1+x/4)(1-0.287)(1043/8.87)Tef/1000 = 0.0838(1-x/4)Tef kilometers. Assuming x=0.04, you have Ts = 1.01Tef, Tt = 0.29Tef, Ht = 0.082Tef. Notice that the mean temp passes from Tef to (Ts+Tt)/2 = 0.65Tef. If Tef = 240 K, then Ts = 242.4 K, Tt = 69.6 K, Ht = 15.6 Km, all more smaller than the real ones. So, adding CO2 you get a small GH effect at the ground and a strong cooling for the whole troposphere. The sole CO2 isn’t enough. 3) Clouds If there is a cloud layer at height Hc = aHt, with 0 ≤ a ≤ 1, then, the system above becomes xTt^4 + (1-x)Tc^4 = Tef^4 Tt/Ts = (Pt/Ps)^(R/Cp) Tc = Ts-a(Ts-Tt) Ht = (Ts-Tt)Cp/g Also, given x and a, the system is closed. Assuming the same values than above, you get Tc = 242.4 Ts = 242.4/(1-0.713a) Tt = 0.287Ts If a = 0.94, then, Ts = 735 K, Tt = 211 K, Ht = 61.6 Km. Very close to real values. Thus, the surface temperature is affected by the lapse rate caused by the CO2 and especially by the height of balance of the clouds liquid droplets, where their weight equals the viscosity of upwelling flow. It's all a team effort between fluid dynamics and radiative transfer. -
Chris G at 05:32 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
I've been testing the water over at Dr. Curry's site. Some commentators are more rational than others. Anteros is currently in my bucket of those who fail the are-we-having-a-rationale-discussion test, for refuting the evidence I could reference with his, apparently, personal conviction. -
mdenison at 04:17 AM on 3 March 2012Wall Street Journal 'Skeptics' Misrepresent the IPCC
It may help those following Anteros' link from real climate to "Lessons from Past Climate Predictions: IPCC FAR" if the older post had an update linking it to this post. -
Philippe Chantreau at 04:09 AM on 3 March 2012Scafetta's Widget Problems
Density of the volumes? Boy, that ought to be some seriously interesting concept. Perhaps it's closely related to the density of the masses... -
Tom Curtis at 04:05 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Eric (skeptic) @52, this post is solely about the greenhouse effect itself, not about how the greenhouse effect will change with increasing CO2 (or other Green House Gas) concentrations. So, although it is true for CO2 that most of the change will be in the wings, as you put it, the absolute effect of current concentrations is strongest in the center of the band. Looking at the last diagram in the OP (from Conrath), you can see the lowest portions of the CO2 trough are about 70 degrees C cooler than the surface. Given the standard lapse rate, that means the effective altitude of radiation to space in those frequencies are is about 10 km. The small spike in the center is from even higher in the atmosphere, and in fact from the stratosphere which is why it is warmer than the surrounding trough. Working our way up the right hand side of the trough, we find small ledges at about 240 and 260 K, indicating the effective altitude of radiation for these frequencies are about 7 and 5 km respectively. Further to the right, at about a wave number of 800, there are two very small troughs that are also caused by CO2. (At least, I am certain the larger is, and I think the smaller is as well.) Clearly for these troughs, the effective altitude of radiation is 1 or 2 km at most. Working to the left, the very uneven series of troughs from wavenumber 350 to 550 are caused by water. The average altitude of effective radiation for these frequencies is 3 - 4 km, but highly variable depending on the exact frequency. These values are fairly representative. The effective altitude of radiation averaged across all frequencies in the IR spectrum is about 5 km. It should be noted that the "effective altitude of radiation" should be understood as (approximately) the average altitude from which radiation reaches space. It has a more technical definition, but for lay purposes treating it as an average is probably accurate enough. (Chris Colose can correct me if he thinks the technical definition is important.) As such, radiation at a given frequency may come from several kilometers above or below the effective altitude of radiation. Measurement of the effective altitude of radiation from space can be done much as I have just done, but using more accurate temperature measurements from radiosondes to calibrate the altitudes. It can also be done by determining the altitude of cloud features visible at particular frequencies. And, as scientists are usually very clever people, it may well have been done by other means I am not familiar with as well. I will leave discussion of how the green house effect changes with increasing CO2 to a later post on the subject, although for CO2, you are correct that the change in intensity (but not the effective altitude of radiation) is primarily on the wings. -
windbarb at 03:28 AM on 3 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
Somebody smarter and with more time than me should create an analogy between a growing national deficit and a growing climate change mitigation deficit- something that would appeal to those who are inclined to see deficits as a major issue to be corrected by extraordinary means. -
desertphile at 02:44 AM on 3 March 2012Trenberth can't account for the lack of warming
It should be stressed, I think, that Trenberth's "travesty" is still not completely resolved: only a partial amount of the "missing" heat has been (likely) found; there is still some heat that we know for near certainty that Earth has accumulated (via radiative measurements "in" and "out"), but where it all is has yet to be determined. I am not convinced Trenberth Fasullo (2011) has accounted for the bulk of the "missing" heat, due to the error bars. The "breakfast napkin" sum I did with the 2011 paper shows some 0.13 w/m^2 to 0.28 w/m^2 missing if the ocean retention hypothesis is correct (which it almost certainly is, but it might not be). The median of the "missing" heat has not been observed (yet). There is a grant proposal being submitted to a few science organizations that seeks to measure the increase (and decrease) in oceanic heat in all four dimensions (i.e., cubic meters over time) to a depth of about 2000 meters. How to do this is a very difficult problem, and it would take an massive amount of money to do properly, and that money will never be provided; but the grant proposal is to perform a short term (minimal ten years) sampling every ten meters. Each buoy would have 200 temperature probes. The problem is that the expense is so great that only a few (30 or so) could be funded, and that is no where near as many as needed: the world's oceans take up a very large volume. The project may never be funded, even for the 30 hoped-for buoy systems. The bottom line is that humanity will never measure with confident accuracy all of the heat gain and loss going on in the oceans. We can at best measure surface and near-surface temperatures, and thereby infer heat, but the error bars will always be wide. -
Bernard J. at 02:26 AM on 3 March 2012The Certainty Monster vs. The Uncertainty Ewok
With respect to that painfully lame Josh 'cartoon', and with a hat tip to one of the themes of this thread, there is only one thing that I would say to the denialati who imagine humour in Josh's writing, and that is:These are not the interpretations that you are looking for...
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Eric (skeptic) at 02:15 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Tom, when you say "atmosphere radiates in those frequency bands from much higher altitudes, and hence at much cooler temperatures" Is that true across the CO2 absorption spectrum or just at the wings (e.g. see end of p. 4643 in http://www.meteo.mcgill.ca/~huang/research/JCLI2874.PDF)? My other question is how much is "much"? Are there satellite measurements of effective radiation altitude? -
Bernard J. at 02:09 AM on 3 March 2012Fritz Vahrenholt - Duped on Climate Change
We cannot try to test eg the temperature with a given level of CO2 and all other factors being equal over and over again. Each of them will have moved on and be different so the circumstances that we need to test the theory in a meaningful way cannot exist.
Either deliberately or mendaciously Elsa is confusing the difficulty of repeatability, with repeatability itself. Further, there comes a point where it is possible to account - both empirically and with repetition - for a certain number of parameters, and begging for more complexity adds no appreciable understanding to the system. In addition, having a repetition of a particular moment of the planet's climate is not a prerequisite for falsifiability, which seems to be Elsa's hook to try to claim that human-caused global warming is not testable science. As scaddenp notes, it seems that Elsa is not as familiar with the meaning of Popper's concept as she pretends. Falsifiability is eminently possibly with the physics of human-caused global warming, although once again it might not be simple to do so. However just because a scientific verification is difficult, it does not mean that it is non-scientific. And frankly, it would not difficult to falsify the physics of human-caused planetary warming... if it were indeed false. That it hasn't been falsified indicates the strength of the science, rather than the weakness. That denialists do not understand this fact indicates the weakness of their understanding of the science. On a related matter, 'simplifying' a description of a system by implying that a single dependent variable (global temperature) should always show direct and consistent correlation with a single independent variable (in this case atmospheric CO2 concentration) is not scientific, and it most certainly does not constitute falsification. Scaddenp has explained this already, but is warrants repeating. That Vahrenholt sees fit to use this gambit is a sign of either his ignorance, or of his politics. -
Alexandre at 00:34 AM on 3 March 2012The Certainty Monster vs. The Uncertainty Ewok
When the focus on uncertainties makes someone overlook the results before his eyes reminds me of that song by The Police: "a blind man looking for a shadow of doubt". -
Tom Curtis at 00:20 AM on 3 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
dunc461 @49, there are no such things as stupid questions. I can understand how you reached your conclusion in that for CO2, nearly all absorption and nearly all radiation is in the wave number 600-700 band shown in the Modtran graph. However, it does not follow. Energy absorbed by CO2 (or any other green house gas) is likely to be transferred to other molecules by collisions long before it is reradiated. From there it may be transferred to water vapour, methane, ozone, or some other greenhouse gas, and radiated in an entirely different part of the spectrum. Of course, much of it is reradiated by CO2, but a significant proportion of the energy radiated by CO2 molecules may well have been carried to those molecules via absorption by other GHG molecules, or even be convection or transfer of latent heat. What is important, therefore, is not the individual paths of any given packets of energy, but the statistical effect of the overall process. That is governed by the fact that in certain frequency bands, nearly all energy radiated from the surface is absorbed in the atmosphere, and that the atmosphere radiates in those frequency bands from much higher altitudes, and hence at much cooler temperatures. The result is a significant reduction of the IR radiation to space from those bands, which must be compensated by higher intensity in those frequencies where radiation can escape to space, which is achieved by a warmer surface. The distinction between tracking individual packets of energy, and the statistical approach may seem like hair splitting to you. Not recognizing the difference does, however, lead to genuine confusions, some of which have motivated some persistent so-called skeptic "myths". In one case I know of, the fact that radiation from individual layers of the atmosphere is in fact half up and half down has led to the mistaken assumption that IR radiation to space must equal the back radiation in those parts of the spectrum absorbed by GHG. That is, of course, false. In fact, downward radiation at the surface is often much larger than the radiation to space because it comes from warmer, lower layers of the atmosphere, while that to space comes from the cooler, higher layers. On a related issue, when you follow the statistical approach, it becomes evident that the back radiation is not necessary for the green house effect (although it does exist, and is significant for some climate effects). In particular, because the lapse rate is independent of radiative transfer in the troposphere, even if there were no back radiation, a greenhouse effect could still exist by modulating the rate of energy transfer by convection to the upper atmosphere. I will be exploring this, and other issues in forthcoming posts in this series. In the meantime, I hope this has been helpful. Finally, I apologize if I was too abrupt in my first response to you. Regulars here can develop a hypersensitive alert system for trolling. The result is we sometime react to legitimate questions as though they were attempts at trolling. We should not do it, but we are human. If you ever read the full sequence of comments in the 2nd Law of Thermodynamics thread linked @48 above, you will understand why. So, if you think you have asked a silly question, it actually means I have just given a poor answer, for which I apologize. I hope this one is more helpful. -
Tom Curtis at 23:45 PM on 2 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
CoalGeologist @45: Case 1: Suppose you have a planet which is a perfect black body, and perfectly conductive. Therefore, the outgoing radiation from the surface of the planet will equal the incoming insolation, and the surface temperature, T, will be (a) T = (I/4s)^0.25, where "I" is the incoming insolation and "s" is the Stefan Boltzmann constant. Case 2: Suppose we have instead the same planet, but now cloaked in an atmosphere which is perfectly absorbing (and emitting) wavelengths. In this case the atmosphere's temperature will be given by equation (a). In this case, because the atmosphere radiates equally up and down, initially it will be cooler, but as the surface warms beneath it, the upward radiation from the surface will rise to match the downward radiation from the atmosphere until both equal the incoming solar radiation. So the temperature of both atmosphere and surface will be given by the equation: (b) TA = TS = (I/4s)^0.25, where the subscripts indicate atmospheric and surface temperatures respectively. Note that in case (2), there is a lot more "pool table ricochets", but the temperature is not increased relative to case (1). Therefore increasing the time it takes for radiation to escape to space is not a sufficient condition to establish a green house effect. I have, of course used a slab model for this discussion, which is inaccurate in life, but allows clarity in seeing the relevant relationships. -
Dikran Marsupial at 23:36 PM on 2 March 2012Scafetta's Widget Problems
Volker I also don't like repetition, so I will just address a couple of points. As KR, Scaddenp, Spherica and Skywatcher suggests, if you want your theory to be taken seriously, then yes, you do need a plausible physical mechanism. "I have refused your claim because I not agree with you on that analysis. A trained eye is able to see in a graph if there is a correlation or not. I have no possibility and no software to calculate a correlation coefficient. But each interested guy can perform such coefficient, because all date are public. It is not necessary that I must perform that. " This is wrong in almost every respect. Firstly we have statistics simply because the eye is unreliable, and an eye that has been trained to see correllations doubly so (as it will see spurious correllations even more readily). Secondly, there is a piece of statistical software called R which is in the public domain, so lack of software is no excuse for not performing the statistical analysis. If you don't understand statistics well enough to perform the analysis, then you need to be more receptive to the advice of those who do. Just measuring the correllation coefficient is easy, what you really need to do is to show that after having investigated the amount of data that you have looked at that it would be unusual to have found a match giving a coefficient as high as that which you observed. This is the test you need to perform to show that the coherence is nothing more than a random artefact. Your last point is the most egregious. It is your theory, this the onus is on you to perform the analysis to suggest that the theory is valid and to defend it against specific scientific criticisms. That is the way science works, whether you like it or not. -
dunc461 at 23:27 PM on 2 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Tom Curtis @43 Thanks again for your response and patience. My concern is not with the accuracy of the models but in trying to understand the process. Somewhere I picked up the concept that the greenhouse effect was caused by the absorption by certain gases of energy radiating from the earth’s surface at specific wave lengths and re-emitting that energy at the same wavelengths, but in all directions so that half of the energy re-emitted is directed back towards earth. This seem plausible to me because if the energy were re-emitted at whole range of wavelengths, some of the energy would be re-emitted in the “transparent windows” and the energy measured, at the top of the atmosphere, in those windows, would be greater than a Black Body Radiation Calculation would predict. Your answer seems to rule out both possibilities so I guess the entire concept is invalid. I apologize for bothering you with my stupid questions. -
Dikran Marsupial at 23:16 PM on 2 March 2012The Independence of Global Warming on Residence Time of CO2
Michael Hauber As I have already pointed out to you, temperature is not the only factor controlling the equilibrium. Another important factor is the level of CO2 in the atmosphere. If you want to discuss hypothetical situations that are unrealistic of the actual carbon system, then that is fine, but is of limited interest to me. The fact that atmospheric CO2 levels are rising more slowly than anthropogenic emissions established beyon reasonable doubt that the natural environment is a net sink hand has been opposing the rise. Any argument that suggests that the oceans were degassing would require the terrertial biosphere to be taking up half of anthropogenic emissions AND the CO2 released by ocean degassing in order for mass to be conserved. Even in that case, the natural environment is still a net sink and is opposing the rise in CO2. Now as it happens, scientists have monitored the oceans, and we know that it is a net carbon sink. See the work of e.g. Corrine Le Quere. -
Tom Curtis at 23:09 PM on 2 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
skymccain @47, not it is correct as written. In that form it exactly mirrors a common so-called climate skeptic argument. The argument made is that heat cannot flow from a cooler to a warmer location, and that therefore back radiation from the atmosphere (which is admittedly cooler than the surface) cannot result in the surface being warmer. In the analogy, the "mechanical breakdown skeptic" claims that the cool water cannot transfer heat to the warm engine block, so that even if the water gets warmer because of the broken pump, it will still be cooler than the engine block and therefore not capable of warming it. The presumed consequence is that the engine will therefore not run hotter because of a faulty water pump. Of course, nobody (or at least nobody sane) would run that argument about cars. But we are repeatedly challenged by so-called skeptics who have incontrovertible proof that "global warming is a lie", where the "proof" turns out be nothing more than the obviously false engine block argument transposed to the atmosphere. As of today, the thread I linked to has 1393 comment from repeated attempts by so-called skeptics to disprove fundamental laws of physics, and patient attempts to show them what is wrong with the argument. -
Dikran Marsupial at 22:43 PM on 2 March 2012The Independence of Global Warming on Residence Time of CO2
owl905 The fact that CO2 levels had been pretty stable between 180ppm and 300ppm for the last 400,000,000 years, even during glaciations, is a pretty good indication that a balancing process exists. The natural carbon cycle has a stable equilibrium as the result of opposing feedback mechanisms balancing. If the equilibrium is peturbed, the balance is lost, and act is to restore the equilibrium. Such dynamic equilibria are common in the natural world. If we peturb the equilibrium with anthropogenic emissions, then the feedbacks will no longer be balanced (e.g. because carbon flux between the atmosphere and oceans depends on the difference in partial pressure between the surface waters and the atmosphere), and the natural environment becomes a net carbon sink, trying to retore the equilibrium. As for glaciation, the peturbation started by Milankovic cycles cools the oceans, which take in more CO2, which reduces the GHE slightly, ice caps grow, increasing abedo, which also results in cooling. The carbon cycle does re-establish the equilibrium, but it takes thousands of years to do so, just as it will take thousands of years to reestablish the equilibrium after we cease anthropogenic emissions (stabilisation will ocurr more quickly). -
fpjohn at 22:33 PM on 2 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
Erp. I see the reference is now linked within the post. yours Frank -
fpjohn at 22:22 PM on 2 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
The Nordhaus response is in the March 22nd issue of the New York Review of Books. http://www.nybooks.com/articles/archives/2012/mar/22/why-global-warming-skeptics-are-wrong/ yours Frank Johnston -
owl905 at 18:53 PM on 2 March 2012Nordhaus Sets the Record Straight - Climate Mitigation Saves Money
Inaction is credit-card environmentalism. Someday someone else can pay the cost to clean up the mess. Anyone that didn't 'get it' from the Stern Report is likely still bunkered down and determined to have the right to freely pollute. -
owl905 at 18:46 PM on 2 March 2012The Independence of Global Warming on Residence Time of CO2
Dikran 15 wrote: "If we cut emissions sharply enough that the net environmental sink outstrips anthropogenic emissions, then atmospheric levels will fall. The choice is in our hands." There's no evidence that such a process or balancing act exists. If the sinks had that magical power and capacity, atmospheric levels would not have stayed at interglacial peaks of 280ppm cycle after cycle. The dance-partners are temperature and moisture. The true significance of the pollution problem has been diagrammed out repeatedly over the last decade - temperature/GHG levels will remain charged for centuries, and future interglacial cycles will respect the additional GHGs in the biosphere. There's a research paper around somewhere that calculates real sequestered-removal is in the order of 2 ppm per cycle. -
skymccain at 18:41 PM on 2 March 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
I enjoyed the post. "Suppose somebody told us their water pump was broken, but that the Second Law of Thermodynamics prohibited transfer of heat from a cooler place (the water) to a hotter place (the engine block), so they'ld be fine so long as they didn't rev any faster than normal, we'ld look at them in complete disbelief." Don't you mean "Suppose somebody told us their water pump was broken, but that the Second Law of Thermodynamics prohibited transfer of heat from a hotter place (the engine block) to a cooler place (the water)"? -
barry1487 at 15:21 PM on 2 March 2012Ice-Free Arctic
There is an updated link to the full version of Polyak et al 2010 http://www.cgd.ucar.edu/staff/mholland/papers/Polyak_2010_historyofseaiceArctic.pdf -
owl905 at 14:59 PM on 2 March 2012The Certainty Monster vs. The Uncertainty Ewok
Many posters here seriously underestimate Curry, and seem to figure the triumphant-truth shows the holes in her empress's new clothes. It's a dangerous underestimation. It hasn't shown holes - just added fuel to her fire. She certainly understands both the subject and the evidence. Her rejections and spin-twists aren't weakness - they're servants to her larger purpose. Her attack at the science has method and a very clear self-centred agenda. Her own words provide the motivation turning point - she was 'vilified' for recommending 'The Hockey Stick Illusion'. After that, she deliberately set about attacking 'the IPCC consensus'. She's selling, not telling - and she doesn't hide the reasons why. -
scaddenp at 13:50 PM on 2 March 2012The Independence of Global Warming on Residence Time of CO2
Sorry didnt include sources: Fischer et al 2008 or Hinrich Schaefer, Michael J. Whiticar, Edward J. Brook, Vasilii V. Petrenko, Dominic F. Ferretti, Jeffrey P. Severinghaus 2006 Ice Record of 13C for Atmospheric CH4 Across the Younger Dryas-Preboreal Transition, Science 25 August 2006: Vol. 313. no. 5790, pp. 1109 - 1112 We report atmospheric methane carbon isotope ratios (13CH4) from the Western Greenland ice margin spanning the Younger Dryas–to–Preboreal (YD-PB) transition. Over the recorded 800 years, 13CH4 was around –46 per mil (); that is, 1 higher than in the modern atmosphere and 5.5 higher than would be expected from budgets without 13C-rich anthropogenic emissions. This requires higher natural 13C-rich emissions or stronger sink fractionation than conventionally assumed. Constant 13CH4 during the rise in methane concentration at the YD-PB transition is consistent with additional emissions from tropical wetlands, or aerobic plant CH4 production, or with a multisource scenario. A marine clathrate source is unlikely.Response:[DB] The Schaefer study can be found here (free download after free registration):
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