# A call for EVIDENCE regarding human caused global warming **URL:** \ **Category:** Great Debates\ **Created:** [February 24, 2006, 12:25pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912 "2006-02-24T12:25:48Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [February 28, 2006, 11:37pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/21 "2006-02-28T23:37:45Z")
> [@intention](#): > > Since then, the solar magnetic field has strengthened, and at present is stronger than it has been in 1,000 years. Yes, I understand the first accurate measurement of the solar magnetic field was recorded in the Domesday Book. I believe they said “low, but rising.” ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [February 28, 2006, 11:56pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/22 "2006-02-28T23:56:47Z")
> [@jshore](#): > > Hmmm…you must have read a different paper than the one I linked to. Either that, or you completely misunderstood the paper. In fact, the paper I linked to uses the observational data to test the models. It demonstrates that the model predictions are in very good agreement with the data but that in order to get this good agreement, it is necessary to include “upper tropospheric moistening”. When they artificially “turn off” this feature of the models, the results are indeed like nothing that is observed thus demonstrating the necessity of this feature in the models in order to reproduce experimental observations. Or, as they summarize it in their introduction: > > If you want to claim this paper does what you say it does, you better start quoting from it to tell us where you get that idea. You are right, I was moving too fast, and I somehow ended up at the Santer et. al. Science paper and not the Soden et. al. Science paper. My apologies, mea culpa. Regarding the Soden paper, whether or not the models can replicate one given part of the climate system is not the question. It’s whether they can replicate the whole climate. It is easy to tune a model to match one part of the climate or another, but to forecast climate, they have to match everything. For example, in the same issue of _Science_, and commenting on the Soden paper, the editors pointed out [here](http://www.sciencemag.org/cgi/content/full/310/5749/795) : > [@](#): > > Cloudy predictions. (Top) Actual effect of clouds on climate (measured CRF) compared to the effect predicted by 19 global climate models. Some of the models significantly overestimate cloud-induced cooling. Of the 19 models listed, only 5 of them were within 25% of being correct on cloud forcing (CRF = cloud radiative forcing), and 5 of them were out by more than 100%. This is hardly a resounding vote of confidence in the models … > [@jshore](#): > > As to your points about theoretical models and theory in general, what is the point of even producing theoretical arguments and models if you are going to decide that they are useless to predict anything and are going to refuse to believe anything they predict?? For example, in weather prediction, perhaps the meteorologists at the National Weather Service should just take observations so that they can tell us what the current weather is and what the past weather was. But, we shouldn’t allow them to predict the future weather because they have no evidence of what that future weather will be other than what their models tell them, which apparently doesn’t count. The point about theory is that any theory is unproven until it is supported by evidence. That’s why there is theoretical physics, and experimental physics. Experimental physics provides the evidence to prove or disprove the theories. My point about the climate is that although it abounds with theories, evidence is very thin on the ground. I have asked for evidence, and have gotten theory … The weather forecasts are often wrong. Should we not make them? No, but we should remember that as they look further ahead, their predictions get worse and worse. See, for example, the [UK Met Office](http://www.metoffice.com/monoutlook/howgood.html), which shows that for forecases 19-31 days out, they do scarcely better than chance. What does that mean about forecasts for next year, or decade, or century? You tell me … > [@jshore](#): > > I am a modeler by profession and I can tell you that when one models any physical system, one can come up with hundreds of things that are being left out of the model and that one might think would mean that the model will be useless. Nonetheless, it usually turns out that the models are in fact extremely valuable. Mind you, I am not arguing for having blind faith in models and theoretical predictions. It is very important to test the models as much as possible…and particularly to test specific physical mechanisms in the models…which is why the Soden et al. paper that I linked to is so important. Since you are a modeler, perhaps you can tell me what statistical tests you apply to the results of your model. For example, does it produce a similar standard deviation, skew, kurtosis, and IQR to the real world data? Because I can assure you, the climate models don’t. Regardless of whether you think that models are reality (they aren’t, which is why physicists still do experiments), the climate models do not produce realistic, life-like results. If you think they do, please point us to some citation for the fact that they do. > [@jshore](#): > > Also, I don’t even see how it is possible to try to find an attribution to the current warming without using theory or models. All we can say by looking at the temperature record is that they earth is warming. In order to answer the question of cause, we have to look at the predictions of models and theory with and without the best estimates of natural and anthropogenic forcings and compare them to what is observed. If, pray tell, you won’t allow us to do that, then exactly how do you propose that we should we try to determine whether the current warming is anthropogenic?!?! Of the 10,000 model results from the recent distributed computing climate model experiment, hundreds and hundreds of the results showed cooling. Is this evidence the world will cool? Of course not. What would I consider evidence? Well, Mars seems to be coming out of an ice age and growing warmer. This, if confirmed, would be evidence that the inner planets are warming, and would support a natural explanation for the earth warming. Recent studies of the effect of cosmic rays on the clouds are certainly evidence for a magnetic solar - earth weather connection, again supporting a natural source for the warming. Evidence is what we garner from observation of the real world. In the real world, the troposphere has not been warming (whether you take UAH or RSS data) as much as is predicted by the models. Which is evidence against the models. In the real world, the South Pole is cooling. This again is evidence against the models. > [@jshore](#): > > [regarding the 10 w/m2 drop in sunlight reaching the earth] > > Well, I wouldn’t say that. You gave an example of an experimental measurement that is not well-understood and seems to be in some contradiction with other measurements (see [here](http://www.realclimate.org/index.php?p=261) for a discussion). And the fact is that sometimes experimental measurements can be wrong and if one abandoned one’s models everytime one got a measurement that didn’t seem explainable by them, you would again be restricting yourself to just observing the universe and never making predictions. For example, the UAH reconstruction of lower tropospheric temperatures from the MSU satellite measurements, which initially showed cooling in contradiction to both surface temperature measurements and model predictions, have turned out to be wrong…as subsequent corrections show. The study I cited is not the only example of large scale swings in albedo. See Long-term global distribution of earth’s shortwave radiation budget at the top of atmosphere, N. Hatzianastassiou et. al., Atmos. Chem. Phys. Discuss., 4, 2671–2726, 2004 © European Geosciences Union 2004. This study shows a similar decline (they show 7 w/m2 vs 10 w/m2 in the earthshine study) over the same time period as the earthshine study. The UAH data never showed long term cooling. It just didn’t warm as fast as the ground surface record … and still doesn’t. The corrections have all been minor, the last one only affecting the tropics. The disagreement with the surface record still exists. Citing the realclimate web site as evidence is a tragic joke. I’ve tried a number of times to ask questions there, and they haven’t printed (or answered) my questions. They only answer the easy questions. Nor is this just my experience, it has happened to a number of people. Plus, they are apologists for Michael Manns behaviour. Again, my call is for evidence. Anyone have some? w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [March 1, 2006, 12:58am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/23 "2006-03-01T00:58:52Z")
Quote: Originally Posted by **intention** Since then, the solar magnetic field has strengthened, and at present is stronger than it has been in 1,000 years. > [@Bryan Ekers](#): > > Yes, I understand the first accurate measurement of the solar magnetic field was recorded in the Domesday Book. > > I believe they said “low, but rising.” Bryan, thank you for posting. Your post inspired me to further research, which is a good thing. I had said strongest in 1,000 years, based on the research by Solanki (The Head of the Max Planck Solar Institute) et. al. done in 2003 and published in _Nature_ magazine. That research showed the current solar activity as being greater now than at any time in the last 1,000 years. What I found was that the same research team has published again, extending the research out to 11,000 years ago. Their research shows that it has been 8,000 years since the the sun has as active as it is today. There is a very comprehensive press release (I’m not a subscriber to “Nature”, no access to the paper) about this recent paper by Solanki et al available [here.](http://www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2004/pressRelease20041028/) It contains illustrations and graphs from the paper. There is a solar hockeystick in the data … go figure. Take a look. Again, my thanks for writing. w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [March 1, 2006, 1:09am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/24 "2006-03-01T01:09:17Z")
> [@Ludovic](#): > > It also seems to me that the “proof” requested is more along the lines of mathematical proof than scientific proof. While the evidence for AGW might not be “so persuasive as to make it foolish to not give tentative agreement,” like most scientific proof, it is dangerous to hold science to its usual high standard when debating policy. > > What are the consequences of waiting until it is too late to change policy to counteract AGW? Too high to require a mathematically-rigorous proof. Which is not to say that we should enact crippling legislation on the flimsiest of proofs, only to say there has to be a balance weighed. Ludovic, I appreciate your post. I haven’t ever requested any “proof” as you seem to think. I’ve just asked for evidence. So far, there’s not been much evidence produced. I’ve read the cited references to the IPCC “Detection and Attribution” section … no evidence there, just computer models. w. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [March 1, 2006, 1:36am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/25 "2006-03-01T01:36:11Z")
> [@intention](#): > > The weather forecasts are often wrong. Should we not make them? No, but we should remember that as they look further ahead, their predictions get worse and worse. Sure, because weather is (as you noted) an extremely complicated turbulent non-linear system, and hence not very well understood theoretically. However, we still have to make plans for future events that will be affected by the weather. So we take long-term weather forecasts into account when making those plans, even though we recognize that the forecasts aren’t reliable. Similarly, we have to make decisions now about things that will affect our global climate in the future. Like it or not, we have to base those decisions partly on our current predictions about climate change, even though we recognize that those predictions don’t have the kind of certainty that we’d expect from predictions about, say, Newtonian mechanics. > [@intention](#): > > What would I consider evidence? Well, Mars seems to be coming out of an ice age and growing warmer. This, if confirmed, would be evidence that the inner planets are warming, and would support a natural explanation for the earth warming. What? Why would you assume that a warming trend for Mars, in addition to a warming trend for the earth, would necessarily constitute definite evidence that **all** the inner planets are warming? There could be lots of alternative explanations for seeing warming trends simultaneously on Mars and Earth. You say you’re refusing to accept AGW (anthropogenic global warming, for any of our readers who’ve forgotten) interpretations of observational results unless the evidence is absolutely incontrovertibly solid in favor of them. In that case, you can’t go off half-cocked and just assume that a warming trend on Mars would necessarily imply a \*\*non-\*\*AGW interpretation, for which the models are **also** not very well understood. > [@intention](#): > > Again, my call is for evidence. Anyone have some? As pointed out earlier, nobody has the kind of evidence that you’re demanding (unless your evidentiary standards are really as lax as they seem to be from your Mars example). You’re demanding from AGW climate models the same certainty and precision that we expect from other physical theories (like, say, Newtonian mechanics) that are far more clearly and fully understood than global climate. Climate is an extremely complicated turbulent non-linear system, and the current models aren’t good enough to give us certainty and precision on that scale. But we don’t have the option of just shrugging and saying, as you seem to want to do, “Well, the evidence concerning the problem isn’t rock-solid, and therefore there’s no need for us to do anything about the problem.” From a scientific point of view, it’s irresponsible to pretend to certainty when we don’t have it; but from a policy point of view, it’s equally irresponsible to demand absolutely certain evidence on an incompletely-understood problem before attempting to do something about it. > [@intention](#): > > The point about theory is that any theory is unproven until it is supported by evidence. That’s why there is theoretical physics, and experimental physics. Experimental physics provides the evidence to prove or disprove the theories. By the way, just FYI, **jshore** has a doctorate in physics, so you don’t have to bother explaining to him the difference between theoretical and experimental physics or similarly basic concepts. ---
**Author:** ![El\_Kabong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/el_kabong/32/496_2.png) [@El\_Kabong](https://boards.straightdope.com/u/El_Kabong)\ **Post date:** [March 1, 2006, 1:38am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/26 "2006-03-01T01:38:22Z")
What, precisely, is the point of this thread? The OP at least talks as though he is considerably better read on this subject than the average member of this board. He certainly has access to scientific papers on the subject, therefore one presumes that if he really wanted to find evidence of human-caused global warming, he could have done so without resorting to asking for it on a general-interest message board. If he has not found such evidence in the peer-reviewed literature, why does he expect it to magically appear here? I contend the OP already believes he knows the answer to his question, at least as he narrowly defines “evidence”. I do not believe he is actually looking for any real evidence of human-caused global warming, but that he is simply making a roundabout argument that in his view there is no such thing, and that therefore there is no justification for taking such steps as legislative action to curb carbon emissions. So, seems more like a harangue, not really a debate. If what the OP really wants to argue is that there is no such thing as human-caused global warming, or that there is no reason to take any action that might reduce its effects, he should just go ahead and do so, without all the misdirection. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [March 1, 2006, 1:55am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/27 "2006-03-01T01:55:13Z")
Well, maybe **intention** can explain his views on this basic evidence in favor of AGW, which is at least as good as the “evidence” for non-AGW that would be provided by a warming Mars. 1. The earth is currently warming, and it has been warming especially rapidly in the last few decades. 2. Human activity has drastically increased the concentration of CO2 in the atmosphere, particularly within the last few decades. 3. [Ice core observations extending back over half a million years](http://www.eurekalert.org/pub_releases/2005-11/aaft-nee111805.php) show that Antarctic climate and greenhouse gases have been closely linked throughout this period. This, to me, constitutes evidence that climate change is strongly dependent on atmospheric CO2 concentrations. It’s not **absolutely definitive** evidence, and there are doubtless other possible explanations that **could** explain it. But it **is** evidence, at least by **intention** ’s “warming Mars” standards. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [March 1, 2006, 2:12am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/28 "2006-03-01T02:12:28Z")
> [@intention](#): > > What I found was that the same research team has published again, extending the research out to 11,000 years ago. Their research shows that it has been 8,000 years since the the sun has as active as it is today. However, the press release you link to acknowledges that there has been no increase in solar activity corresponding to the sharp rise in global temperature in the last 20 years or so: > [@](#): > > Because the brightness of the Sun varies slightly with solar activity, the new reconstruction indicates also that the Sun shines somewhat brighter today than in the 8,000 years before. Whether this effect could have provided a significant contribution to the global warming of the Earth during the last century is an open question. The researchers around Sami K. Solanki stress the fact that solar activity has remained on a roughly constant (high) level since about 1980 - apart from the variations due to the 11-year cycle - while the global temperature has experienced a strong further increase during that time. > [@intention](#): > > Citing the realclimate web site as evidence is a tragic joke. I’ve tried a number of times to ask questions there, and they haven’t printed (or answered) my questions. Well, there are at least two possible explanations for a lack of response from a scientific commentary website. It could be that the respondents aren’t actually scrupulous and/or competent enough to answer the questions, or it could be that the questions aren’t intelligent and/or meaningful enough to be worth answering. At present, we don’t seem to have enough evidence about you or about [www.realclimate.org](http://www.realclimate.org) to determine which explanation is the true one. I note, however, that [realclimate.org](http://realclimate.org)’s “about” page describes them as “a commentary site on climate science by working climate scientists” who aim “to provide a quick response to developing stories”. So there seems no reason to expect that they would “print questions” from correspondents who are’t working climate scientists, irrespective of the questions’ merit. ---
**Author:** ![bizzwire](https://avatars.discourse-cdn.com/v4/letter/b/958977/32.png) [@bizzwire](https://boards.straightdope.com/u/bizzwire)\ **Post date:** [March 1, 2006, 2:24am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/29 "2006-03-01T02:24:17Z")
> [@ralph124c](#): > > or take the case of greenland and iceland: colonized by the Vikings (from about 900 AD- 1400 AD). The Norse sagas relate that Iceland was forested with birch trees in the beginning 9the trees were all chopped down by the settlers). So let me get this straight; computer models are not acceptable (per the **OP** ), but Norse Sagas are ok? ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 1, 2006, 3:20am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/30 "2006-03-01T03:20:15Z")
> [@intention](#): > > Regarding the Soden paper, whether or not the models can replicate one given part of the climate system is not the question. It’s whether they can replicate the whole climate. It is easy to tune a model to match one part of the climate or another, but to forecast climate, they have to match everything. Where does it say that they “tuned” the model? My impression is they simply ran it in the mode where it is normally run. And, it is not like these models have oodles and oodles of free parameters (although they do have some parameters that are uncertain) so, no, it is not so easy to tune them to match many different aspects of climate. > [@](#): > > Of the 19 models listed, only 5 of them were within 25% of being correct on cloud forcing (CRF = cloud radiative forcing), and 5 of them were out by more than 100%. This is hardly a resounding vote of confidence in the models … Well, clouds are indeed a source of considerable uncertainty. However, it is worth noting that those different models that all have various degrees of correctness in how they model clouds still all predict considerable warming due to greenhouse gas emissions. So, it seems that the models are fairly robust in this regard. One of the reasons why the models don’t have to be too perfect is that the simulations are generally run by running the models with and without the greenhouse gas forcing and then subtracting the difference, so you don’t have to do a particularly good job simulating everything as long as you don’t miss some sort of strong dependence on a change in greenhouse gas forcing. > [@](#): > > The point about theory is that any theory is unproven until it is supported by evidence. That’s why there is theoretical physics, and experimental physics. Experimental physics provides the evidence to prove or disprove the theories. That is why there is a whole field of study where the models are compared to past climate variations, checked against seasonal changes in climate, checked to see if their “noise” is similar to the “noise” in the real climate system, etc., etc. That is not to say it is a difficult problem when one has only one earth’s climate system to study. However, these same sort of difficulties are faced in other fields such as geology and biological evolution. > [@](#): > > The weather forecasts are often wrong. Should we not make them? No, but we should remember that as they look further ahead, their predictions get worse and worse. See, for example, the [UK Met Office](http://www.metoffice.com/monoutlook/howgood.html), which shows that for forecases 19-31 days out, they do scarcely better than chance. What does that mean about forecasts for next year, or decade, or century? You tell me … Okay…I’ll admit I brought up the weather analogy. However, I am sure that you are aware that there is a big difference between predicting weather and predicting climate. One means following a specific solution to a complicated set of PDEs whereas the other is just looking at average quantities. The forecasters now run ensembles with perturbed initial conditions in order to see how sensitive their solutions are to initial conditions. The same thing is often done in climate model simulations and although the solutions certainly differ in their wiggles, they tend to all predict similar results for the basic question of how much warming occurs with rise in greenhouse gases. > [@](#): > > Because I can assure you, the climate models don’t. Regardless of whether you think that models are reality (they aren’t, which is why physicists still do experiments), the climate models do not produce realistic, life-like results. > > If you think they do, please point us to some citation for the fact that they do. Well, the models are not perfect…but their results are realistic in a wide variety of ways. I’d recommend the IPCC report for references on this. > [@](#): > > Of the 10,000 model results from the recent distributed computing climate model experiment, hundreds and hundreds of the results showed cooling. Because of the simplified coupling that they were using between the atmosphere and oceans (in order to run so many realizations), some of the runs (6 out of the 414 model versions) suffered from a known flaw in this and did lead to significant cooling but that these runs were clearly different easy to identify as physically unrealistic and eliminate. Once that is done, there are almost no models that show a sensitivity of less than 2 C for a doubling of CO2 and some show a sensitivity as high as 11 C. (Such a high sensitivity can probably be discounted on the basis of other evidence such as the glacial-interglacial cycles.) See [here](http://climateprediction.net/science/pubs/nature_first_results.pdf) for the Nature article of their results. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 1, 2006, 3:41am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/31 "2006-03-01T03:41:26Z")
> [@intention](#): > > What would I consider evidence? Well, Mars seems to be coming out of an ice age and growing warmer. This, if confirmed, would be evidence that the inner planets are warming, and would support a natural explanation for the earth warming. [Here](http://www.realclimate.org/index.php?p=192) is a piece on RealClimate (which, yes, I know you don’t like) discussing the supposed “global warming” on Mars. It concludes: > [@](#): > > Thus inferring global warming from a 3 Martian year regional trend is unwarranted. The observed regional changes in south polar ice cover are almost certainly due to a regional climate transition, not a global phenomenon, and are demonstrably unrelated to external forcing. There is a slight irony in people rushing to claim that the glacier changes on Mars are a sure sign of global warming, while not being swayed by the much more persuasive analogous phenomena here on Earth… This whole thing also illustrates the very poor state of the science on the naysayer side of the global warming debate. Because, even if Mars were warming, given that its atmosphere is way way different than ours and that those who posit a sun-climate connection necessarily need to invoke some sort of exotic mechanism (like a dramatic effect on clouds) in order to have a prayer of making it work, it seems like it would be very unlikely that the same mechanism would work on Mars. > [@](#): > > Recent studies of the effect of cosmic rays on the clouds are certainly evidence for a magnetic solar - earth weather connection, again supporting a natural source for the warming. Give me a break! All we basically have on the sun-climate thing is people trying in vain to search for a correlation. When they find one, it tends to break down over the last 20-30 years and, plus, is often given without even an attempt to justify a mechanism. (See [here](http://www.realclimate.org/index.php?p=171).) And then, they have to find a mechanism by which the known forcing due to greenhouse gases miraculously gets cancelled out once feedbacks are taken into account. You seem to have two standards here: If one is proposing that climate change is due to anthropogenic greenhouse gases, then it is not enough to show (e.g.) how the models can only reproduce the warming, the thermal structure of the oceans, etc. with currently understood estimates of forcings if one includes the greenhouse gas effects. However, if one is proposing that climate change is due to natural causes, then you don’t have to show anything. You just come up with a few vague ideas or some correlation that seemed to at least hold until recently. You don’t have to model anything or show how the structure of the warming actually agrees with your mechanism. > [@](#): > > In the real world, the troposphere has not been warming (whether you take UAH or RSS data) as much as is predicted by the models. Which is evidence against the models. I don’t think that is true. I believe the RSS data is pretty much right there with what the models predict for the lower troposphere warming relative to the surface warming. The UAH data is still a little off…but not much, particularly given the error bars in this. And, of course, the UAH data has been trending upward with time as it gets corrected. > [@](#): > > In the real world, the South Pole is cooling. This again is evidence against the models. [Not really.](http://www.realclimate.org/index.php?p=18) > [@](#): > > The UAH data never showed long term cooling. It just didn’t warm as fast as the ground surface record … and still doesn’t. The corrections have all been minor, the last one only affecting the tropics. The disagreement with the surface record still exists. No…It did originally show cooling before they took the orbital decay of the satellites into account. And, the corrections have been significant and the remaining disagreement with the surface record is not that large…In fact, I think it is only very significant in the tropics and a recent assessment concluded that the remaining disagreement is most likely due to remaining errors in the reconstruction itself. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 1, 2006, 3:54am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/32 "2006-03-01T03:54:31Z")
For a discussion on reconciling temperature trends in the lower atmosphere, see [this](http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/default.htm) draft report from the U.S. Climate Change Science Program. Note these conclusions iin the executive summary: > [@](#): > > For global-mean temperature changes in the new climate model simulations, some show more warming in the troposphere than at the surface, while a slightly smaller number of simulations show the opposite behavior. Given the range of observed results and the range of model results, there is no inconsistency between models and observations at the global scale. > [@](#): > > In the tropics, the agreement between models and observations depends on the time scale considered. For month-to-month and year-to-year variations, models and observations both show amplification (i.e., the month-to-month and year-to-year variations are larger aloft than at the surface). The magnitude of this amplification is essentially the same in models and observations. On decadal and longer time scales, however, while almost all model simulations show greater warming aloft, most observations show greater warming at the surface. > > These results have at least two possible explanations, which are not mutually exclusive. Either amplification effects on short and long time scales are controlled by different physical mechanisms, and models fail to capture such behavior; and/or remaining errors in some of the observed tropospheric data sets adversely affect their long-term temperature trends. **The second explanation is judged more likely.** (bolding mine) ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [March 1, 2006, 5:51am UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/33 "2006-03-01T05:51:57Z")
On the issue of Greenland’s Ice Cap: The thickness of the center of a Continental Glacier is determined by the rate of deposition of new Ice. The total area and the thickness of the margins are determined by the rate of flow, and the rate of melt. A more energetic atmosphere (warmer earth) would, in all likelihood cause more snow to deposit in the colder central highlands of Greenland than would be deposited in a cooler atmosphere. The higher temperature would affect the overall plasticity and flow, and the rate of melt at near sea level. On the beginnings of the warming period, and the role of human activity: Deforestation begun in earnest in the northern hemisphere in the 1400’s would have a slow cumulative effect on the carbon cycle, including burning wood in the newly invented fireplaces and clearing forests for the newly planted fields. In addition, the gradual increase in root crops that were grown to adapt to the very cool spring and fall condition in the inhabited parts of Eurasia during the “little ice age” involve a far more thorough aeration of the soil, encouraging the formation of methane, and the release of soil gasses into the atmosphere. While trivial compared to fossil fuel use in the twentieth century, it represents an early beginning in continent wide, and even world wide anthropogenesis in the process of change in the atmosphere. Hard data on the subject of temperature, and climate is just reaching its first century. That data deals almost exclusively with the northern hemisphere, and overwhelmingly with North America. (Family history buff, my grandfather installed the first recording systems in hundreds of locations for the US Weather Service, now the NOAA.) Prior to that, instrumentation was haphazard, where extant, which was pretty much none. Single source data for decades long periods simply did not exist until that collection system had had half a century to accumulate data. Even now, it is only a partial look at one century, which in climatology is single squint through a small peephole. That said, the entire body of evidence does support the theory that climate is warming, and it is warming in the places that people inhabit more than in the places where there are no people. That first shot lands squarely in the target for anthropogenesis. It is of further note that there is no evidence that reducing greenhouse emissions would have no effect on climate. Even a warming trend with other causative factors would show some response to significant changes in the levels of the most important gasses. To posit that that change is more likely to have no effect, or cause more warming is ludicrous. Tris ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 1, 2006, 1:55pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/34 "2006-03-01T13:55:41Z")
By the way, another source of information on some of the evidence for anthropogenic climate change is presented in [this](http://www.realclimate.org/index.php?p=258) RealClimate posting (under the header **To what extent is “Global Warming Theory” verified?** ). Note, for example, that the greenhouse gas mechanism can explain the observed simultaneous warming of the lower troposphere and cooling of the stratosphere, whereas I think that this is harder to do with a solar mechanism (certainly a direct one; I am not sure about one involving a cloud feedback). ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [March 2, 2006, 11:14pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/35 "2006-03-02T23:14:45Z")
> [@jshore](#): > > Give me a break! All we basically have on the sun-climate thing is people trying in vain to search for a correlation. When they find one, it tends to break down over the last 20-30 years and, plus, is often given without even an attempt to justify a mechanism. (See [here](http://www.realclimate.org/index.php?p=171).) Ummm … not really. I don’t really understand why people think the cosmic ray - solar magnetism - clouds relationship is unknown or unstudied. Additional known and studied mechanisms are solar UV changes affecting the atmosphere, as well as direct changes in the total solar irradiance. For examples of studies showing effects and mechanisms, see: Marsh, N.D. and Svensmark, H. 2000. Low cloud properties influenced by cosmic rays. Physical Review Letters 85: 5004-5007. G., N. Marsh, G.A. Kovaltsov, K. Mursula, and O.G. Gladysheva, Latitudinal dependence of low cloud amount on cosmic ray induced ionization, Geophys. Res. Lett., Marsh, N., and H. Svensmark, Galactic Cosmic ray and El Niño-Southern Oscillation trends in ISCCP-D2 low-cloud properties, J. Geophys. Res., 108(D6), AAC 6-1, doi:10.1029/2001JD001264, 2003. Marsh, N., and H. Svensmark, Solar influence on earth’s climate, Space Sci. Rev., 107, 317-325, 2003. Palle Bago, E. and Butler, C.J. 2000. The influence of cosmic rays on terrestrial clouds and global warming. Astronomy & Geophysics 41: 4.18-4.22. Svensmark, H. and Friis-Christensen, E. 1997. Variation of cosmic ray flux and global cloud coverage - A missing link in solar-climate relationships. Journal of Atmospheric and Solar-Terrestrial Physics 59: 1225-1232. Kniveton, D.R. and Todd, M.C. 2001. On the relationship of cosmic ray flux and precipitation. Geophysical Research Letters 28: 1527-1530. Marsden, D. and Lingenfelter, R.E. 2003. Solar activity and cloud opacity variations: A modulated cosmic ray ionization model. Journal of the Atmospheric Sciences 60: 626-636. Palle Bago, E. and Butler, C.J. 2000. The influence of cosmic rays on terrestrial clouds and global warming. Astronomy & Geophysics 41: 4.18-4.22. Feynman, J. and Ruzmaikin, A. 1999. Modulation of cosmic ray precipitation related to climate. Geophysical Research Letters 26: 2057-2060. Shaviv, N.J. and Veizer, J. 2003. Celestial driver of Phanerozoic climate? GSA Today 13 (7): 4-10. Solanki, S.K., Schussler, M. and Fligge, M. 2000. Evolution of the sun’s large-scale magnetic field since the Maunder minimum. Nature 408: 445-447. Svensmark, H. 1998. Influence of cosmic rays on Earth’s climate. Physical Review Letters 22: 5027-5030. Marsden, D. and Lingenfelter, R.E. 2003. Solar activity and cloud opacity variations: A modulated cosmic ray ionization model. Journal of the Atmospheric Sciences 60: 626-636. Pang, K.D. and Yau, K.K. 2002. Ancient observations link changes in sun’s brightness and earth’s climate. EOS, Transactions, American Geophysical Union 83: 481,489-490. Hengyi Weng Journal of Atmospheric and Solar-Terrestrial Physics. Volume 67, Issues 8-9 , May-June 2005, Pages 793-805 (Solar and Heliospheric Influences on the Earth’s Weather and Climate Tourpali, K., Schuurmans, C.J.E., van Dorland, R., Steil, B. and Bruhl, C. 2003. Stratospheric and tropospheric response to enhanced solar UV radiation: A model study. Geophysical Research Letters 30: 10.1029/2002GL016650. ZHEREBTSOV, G.A., V.A. Kovalenko and S.I. Molodykh, 2005. The physical mechanism of the solar variability influence on electrical and climatic characteristics of the troposphere. Advances in Space Research Vol. 35, No 8, pp. 1472-1479, August 2005 WANG, Yongjin et al., 2005. The Holocene Asian Monsoon: Links to Solar Changes and North Atlantic Climate. Science, Vol. 308, No 5723, pp. 854-857, May 6, 2005 TOURPALI, K., C. J. E. Schuurmans, R. van Dorland, B. Steil, C. Brühl, and E. Manzini, 2005. Solar cycle modulation of the Arctic Oscillation in a chemistry-climate model. Geophys. Res. Lett., 32, L17803, doi:10.1029/2005GL023509, September 3, 2005 ---
**Author:** ![kingpengvin](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kingpengvin](https://boards.straightdope.com/u/kingpengvin)\ **Post date:** [March 3, 2006, 3:31pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/36 "2006-03-03T15:31:39Z")
> [@ralph124c](#): > > incidentally , for those who belive that human generated CO2 is to blame: erupting volcanos emit huge amounts of CO2 and sulphur dioxide. Do times of heavy volcanic activity coincide with warming or cooling? the last major eruption of Tambora (East indies) resulted in the famous 1806 “year without Summer”-it snowed in every month in New England, and the corn crop in Massachusetts failed (killing frosts in July). You do realize that a volcanic erruptions also results in a lot of ash and debris scattered into the atmosphere and in the case of huge erruptions enough is sent into the atmosphere to block some sunlight. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 4, 2006, 3:54pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/37 "2006-03-04T15:54:03Z")
> [@intention](#): > > Ummm … not really. I don’t really understand why people think the cosmic ray - solar magnetism - clouds relationship is unknown or unstudied. Additional known and studied mechanisms are solar UV changes affecting the atmosphere, as well as direct changes in the total solar irradiance. For examples of studies showing effects and mechanisms, see: Yes, there are a mish-mash of known and hypothesized mechanisms, some observed correlations over some time periods, etc. But, like I said, they haven’t come together to constitute any sort of quantitative explanation of how the current warming could be accounted by solar forcing. The papers you link to illustrate that. Some of them don’t even try to address the issue of whether solar effects can account for the current warming. It is poor logic to claim that any paper that talks about solar forcing supports your idea that the current changes are due to that. Clearly, it is understood that the sun plays an important role in our climate…and it is also well-accepted, for example, that the ice age - interglacial oscillations over the last couple million years were triggered by various (Malinkovitch) oscillations in the earth’s orbit that affect solar insolation. As another example, while “the jury is still out” on the proposed cosmic ray forcing mechanism of Svensmark, the observed trend in these cosmic rays doesn’t agree with the recently observed warming. (See [here](http://www.realclimate.org/index.php?p=42).) [Here](http://www.uwmc.uwc.edu/geography/globcat/globwarm/solar-00.htm) is another example of a widely-touted correlation between sunspot cycle and temperature which has broken down in the past ~25 years. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 4, 2006, 4:08pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/38 "2006-03-04T16:08:38Z")
> [@kingpengvin](#): > > You do realize that a volcanic erruptions also results in a lot of ash and debris scattered into the atmosphere and in the case of huge erruptions enough is sent into the atmosphere to block some sunlight. Also, while I think it is true that way back in time when there was **much** more volcanic activity, it could significantly effect the CO2 level, the contribution these days is very small…[an average of \<0.1 Gigatons of carbon per year as compared to 5.3 GT from fossil fuel burning](http://www.grida.no/climate/ipcc_tar/wg1/fig3-1.htm). (I am not even sure you can see any signal in CO2 from the eruption of Mt. Pinatubo in 1991, for example…[at least I can’t see it](http://cdiac.ornl.gov/trends/co2/sio-mlo.htm).) By contrast, it is well-understood and observed that such eruptions cause cooling because of their emission of aerosols, as you note. In fact, the response to this eruption has even been used to check on the climate sensitivity, specifically the climate models’ handling of the water vapor feedback. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 4, 2006, 4:46pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/39 "2006-03-04T16:46:54Z")
Here are a couple of papers that critically analyze some of the claimed correlations between solar activity and climate: [P. Laut, Solar activity and terrestrial climate: an analysis of some purported correlations, J. Atmospheric and Solar-Terrestrial Physics **65** , 801-812 (2003).](http://stephenschneider.stanford.edu/Publications/PDF_Papers/Laut2003.pdf) [P. E. Damon and P. Laut, Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data, EOS **85** , 370 (2004).](http://stephenschneider.stanford.edu/Publications/PDF_Papers/DamonLaut2004.pdf) ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [March 8, 2006, 9:41pm UTC](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912/40 "2006-03-08T21:41:07Z")
> [@jshore](#): > > Here are a couple of papers that critically analyze some of the claimed correlations between solar activity and climate: > > [P. Laut, Solar activity and terrestrial climate: an analysis of some purported correlations, J. Atmospheric and Solar-Terrestrial Physics **65** , 801-812 (2003).](http://stephenschneider.stanford.edu/Publications/PDF_Papers/Laut2003.pdf) > > [P. E. Damon and P. Laut, Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data, EOS **85** , 370 (2004).](http://stephenschneider.stanford.edu/Publications/PDF_Papers/DamonLaut2004.pdf) jshore, thanks for the references. The second one merely points out that one of the papers showing a climate/solar link contains errors in the post 1980 section. The first one shows very good agreement between solar and climate until 1980, at which point the solar component disappears … We have several choices regarding these papers. We can ascribe the change to: 1. Solar influence on the planet abruptly disappearing in 1980 (extremely doubtful) 2. CO2 having no influence until 1980, then suddenly dominating the solar influence. (extremely doubtful). 3. Problems with the surface temperature record. (extremely probable, particularly given the widespread closing of rural temperature stations in the 1980s) Regardless of the explanation of the post 1980 record, these papers support my argument that the sun has a huge influence on climate. Yes, they point out the post 1980 difference, but\*\*\* up until 1980, both papers show that 100% of the temperature changes can be explained by solar changes.\*\*\* However, none of this is particularly to the point of the thread, as it does not provide evidence for AGW. Instead, it shows that AGW is not necessary to explain climate changes up until 1980 at least … w. [Previous page](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912.md?page=1) [Next page](https://boards.straightdope.com/t/a-call-for-evidence-regarding-human-caused-global-warming/345912.md?page=3)