# Is Anthropogenic Global Warming Falsifiable? **URL:** \ **Category:** Great Debates\ **Created:** [June 16, 2009, 5:03am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911 "2009-06-16T05:03:51Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [June 30, 2009, 5:32am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/101 "2009-06-30T05:32:03Z")
> [@Blake](#): > > The ~70s cooling event didn’t kill the theory despite the skeptics saying that it should. All that happened was that a more elaborate model was created (incorporating aerosols) to incorporate the apparently contradictory observation. > > The cooling of the past 12 years will go exactly the same way, and we’ve already seen papers predicting 20 more years of cooling as a result of AGW, based on their preliminary models. > > The lack of correlation between proxies and the actual temperatures of the past 20 years hasn’t killed it despite the skeptics saying it should. Instead the proponents are looking for ways to incorporate the apparently contradictory theory into their models. > > And so on and on for every incident where the theory has failed some predictive test. I see absolutely no reason to believe that the same would not have been done for any contradictory satellite data. > > Can you provide some evidence that this would not be the case, to support your repeated assertions that it is would not? Because people corrected for new data as it came in, they’re wrong? There’s possibly thousands of different, shifting variables that effect the climate. How do you expect people to discover those before they shift in such a way as to change the climate in an unexpected way? Climate modeling is an iterative process, and there’s no reason to expect otherwise. You make your best guess, try it against the real climate, see how it’s going wrong, form a hypothesis for why, add that back in, and see if it’s closer to real than it was before. Rinse and repeat. No one has ever said that we won’t discover something which explains everything in a way that makes greenhouse emissions suddenly become a non-issue. But, the sheer existence of unforeseen possibilities isn’t a proof that an unforeseen possibility must be the real answer, and I can’t think why you would expect it to be. It makes more sense to say that as various other factors are isolated, the closer things come to proving AGW if what remains matches greenhouse gas emissions volume more closely, which is I believe what’s happening. > [@](#): > > But I will ask you yet again: what evidence can I collect that I can collect that will cause you to reject AGW? Well first of all, you need to _try_. I’m not seeing why it’s our job to tell you how to make your case. If you think you have a case, then _make it_ and don’t just keep crying that we’re not making it for you. Just to give you a bone, in the 50 year period from 1150-1200, the amount of volcanic gases and solar irradiance was fairly well an exact match to that of today from best we can tell.[sup]1[/sup] Judging by our various reconstructions via proxy data, the global temperature during that time period was probably about -0.3C compared to the 1961-1990 mean[sup]2[/sup] (which is 14.00C[sup]3[/sup]). We’ve been a match for the 1150-1200 volcanic/solar data since at least 1974. The average temperature from then (1974) to 2008 is +0.27C.[sup]4[/sup] Dividing that period into 5 year blocks, we have: 1974-1978 = -.03C 1979-1983 = +0.17C 1984-1988 = +0.17C 1989-1993 = +0.24C 1994-1998 = +0.37C 1999-2003 = +0.45C 2004-2008 = +0.53C So, firstly, explain why our modern era is 0.57C higher than the 1150-1200 period. Secondly, explain what has been causing the rise in temperature over the last 35 years if it isn’t the sun and volcanoes. [sup]1[/sup] [http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1\_Print\_Ch06.pdf](http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch06.pdf) p. 477 (Note that the baseline is the 1500-1899 mean) [sup]2[/sup] IPCC Ch. 6, p. 467 (Baseline is 1961-1990 mean) [sup]3[/sup] [http://www.eoearth.org/article/Global\_warming](http://www.eoearth.org/article/Global_warming) [sup]4[/sup] [http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt](http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt) (Baseline is 1951-1980, 14C) ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 30, 2009, 5:47am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/102 "2009-06-30T05:47:44Z")
> [@WarmNPrickly](#): > > So maybe tree rings aren’t the best indicator of climate. That would be a bummer, but not because it has any say on AGW. Except that it does. Most models incorporate tree ring data. Either it turns out that they don’t match temperature and improve model fit anyway, or they do match the temperature and the models are wrong. Neither option makes the modelling exercises look good. > [@](#): > > AGW comes down to the physical absorbtion of thermal radiation by CO2. You can debate figures on how much warming it will cause, but you can’t argue that it wont cause warming without violating physical laws. That is falsifiable. Nonsense. This is exactly like the creationists saying that evolution violates the laws of thermodynamics. CO2 absorbs heat in a bottle, cows eat grass in a cage, people eat food in a hospital. That doesn’t allow you to extrapolate the effect of those processes on a chaotic system on a global scale. No physical laws need to be violated for increases on CO2 to have absolutely no measurable effect on global temperature. All we need is some alternative mechanism to increase heat transference to space (eg increased storms), decrease radiation (eg global dimming) or, increase albedo (eg cloud over). Saying that any climate observation violates the laws of physics shows a gross ignorance of how uncertain our understanding of climate is. At best we have theories, not laws. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 30, 2009, 6:07am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/103 "2009-06-30T06:07:26Z")
> [@GIGObuster](#): > > And I still agree with **wevets** that there are still other items that can falsify AGW. Then tell us what they are. > [@Sage\_Rat](#): > > Because people corrected for new data as it came in, they’re wrong? No, because the theory _allows_ them to incorporate _any_ data as it comes in it’s not science. The problem isn’t with incorporating new data. The problem is that there is no data that _can’t_ be incorporated. > [@](#): > > How do you expect people to discover those before they shift in such a way as to change the climate in an unexpected way? I don’t. Popper, however, demands that the proponents of a supposedly scientific theory to state clearly what shifts are incompatible with the theory. Can you do that? > [@](#): > > Climate modeling is an iterative process, and there’s no reason to expect otherwise. You make your best guess, try it against the real climate, see how it’s going wrong, form a hypothesis for why, add that back in, and see if it’s closer to real than it was before. Rinse and repeat. Yep, just like Intelligent Design, or Freudian Psychology or Astrology. I have no problem with iterative sciences per se. The problem comes when the proponents can not make predictions that would be incompatible with their hypothesis. > [@](#): > > But, the sheer existence of unforeseen possibilities isn’t a proof that an unforeseen possibility must be the real answer, and I can’t think why you would expect it to be. Nor do I. > [@](#): > > It makes more sense to say that as various other factors are isolated, the closer things come to proving AGW if what remains matches greenhouse gas emissions volume more closely, which is I believe what’s happening. Huh??? You seem to have lost the end of your sentence. If without then. “if what remains matches greenhouse gas emissions volume more closely then…..??? > [@](#): > > Well first of all, you need to _try_. I’m not seeing why it’s our job to tell you how to make your case. Then you need to read the article by Popper, because **that is precisely your job**. If you can’t tell me how to falsify your theory then your theory isn’t scientific. > [@](#): > > If you think you have a case, then _make it_ and don’t just keep crying that we’re not making it for you. Again, all you are doing here is hollering loudly that you can never make AGW meet the Popperian definition of science. I’m not crying that you aren’t making my case. I’m crying that you aren’t meeting the most basic Popperian standard of science. But thank you for making it so clear to everyone that you agree that AGW can not meet that standard of science. > [@](#): > > So, firstly, explain why our modern era is 0.57C higher than the 1150-1200 period. Secondly, explain what has been causing the rise in temperature over the last 35 years if it isn’t the sun and volcanoes. An unknown process. I’ll say it again: You don’t need to accept my theory that the dark matter/energy discrepancy is caused by pixies just because you haven’t discovered an alternative explantion yet. A scientist isn’t required to accept an unscientific hypothesis just because she has no better alternative. That’s not how science works. An admission of ignorance is always acceptable in science, no alternative need be postulated. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [June 30, 2009, 6:27am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/104 "2009-06-30T06:27:28Z")
> [@Blake](#): > > Except that it does. Most models incorporate tree ring data. Either it turns out that they don’t match temperature and improve model fit anyway, or they do match the temperature and the models are wrong. Neither option makes the modelling exercises look good. The models are only quibling a few degrees C. None of them are predicting cooling. The models can all be wrong and it wouldn’t change AGW. > [@](#): > > Nonsense. This is exactly like the creationists saying that evolution violates the laws of thermodynamics. Evolution doesn’t violate the laws of thermodynamics in any way. It’s not even related. > [@](#): > > CO2 absorbs heat in a bottle, cows eat grass in a cage, people eat food in a hospital. That doesn’t allow you to extrapolate the effect of those processes on a chaotic system on a global scale. > > No physical laws need to be violated for increases on CO2 to have absolutely no measurable effect on global temperature. Yes, they do. CO2 doesn’t change it’s properties once it’s out in the atmosphere. The earth radiates energy, CO2 absorbs it. It isn’t a cow. > [@](#): > > All we need is some alternative mechanism to increase heat transference to space (eg increased storms), decrease radiation (eg global dimming) or, increase albedo (eg cloud over). None of this changes the fact that CO2 absorbs IR. It may change how much, but it wont change that it does. Increased CO2 leeds to increased temperature. Wave your hands with maybe’s all you like, CO2 absorbs thermal radiation. The earth emits thermal radiation. > [@](#): > > Saying that any climate observation violates the laws of physics shows a gross ignorance of how uncertain our understanding of climate is. At best we have theories, not laws. Well then it’s a good thing nobody said that. The law is that CO2 increases the earths temperature, not how much. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [June 30, 2009, 6:29am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/105 "2009-06-30T06:29:29Z")
> [@Blake](#): > > Huh??? You seem to have lost the end of your sentence. If without then. > “if what remains matches greenhouse gas emissions volume more closely then…..??? What remains ties in to AGW IF the levels match emission levels. There is no “then”. > [@](#): > > Then you need to read the article by Popper, because **that is precisely your job**. If you can’t tell me how to falsify your theory then your theory isn’t scientific. I have told you how to disprove it, way back on page 1 and again in my last post. All you have to do is find something which explains the current and historic climate better than the currently accepted science. If you can make a climate model that comes closer to reality than what we have and it doesn’t rely on greenhouse gas emissions to accomplish it, then you’re reducing the possible effects of greenhouse gases to whatever difference still remains between your model and real. If you can show that greenhouse gases aren’t collecting in the atmosphere like believed, then there’s a decent chance that you’ve disproved global warming. If you can show that Earth’s atmosphere has no effect on planetary temperature, then you’ve entirely disproved AGW. There’s any number of ways to disprove AGW wholly or nip off the amount of climate that can be attributed to gases, but stated most simply, “All you have to do is find something which explains the current and historic climate better than the currently accepted science.” Isolate everything there is in the climate and explain it all, and if there’s no AGW, then there you go. But so far, isolating things has only established _how much of_ our current climate is due to greenhouse gases, rather than showing _how little of_ it is. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 30, 2009, 6:32am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/106 "2009-06-30T06:32:36Z")
> [@GIGObuster](#): > > [http://en.wikipedia.org/wiki/Carbon\_dioxide\_in\_the\_Earth's\_atmosphere](http://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmosphere) Umm… that’s not showing that the human emitted CO2 is **significantly** absorbing CO2. > [@](#): > > [How do human CO2 emissions compare to natural CO2 emissions?](http://www.skepticalscience.com/human-co2-smaller-than-natural-emissions.htm) > > > [@](#): > > > > While the ocean absorbs around half of human CO2 emissions, empirical observations reveal the oceans are losing their ability to absorb CO2. Except we are separately seeing increased acidification of the oceans demonstrating increased absorbtion. > [@](#): > > I guess if you blink you will miss it (posted 2 times already): > > [http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/](http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/) I’ve expressed my lack of faith in models elsewhere. And I’d rather not wait 50+ years for results. More research is required! ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [June 30, 2009, 6:38am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/107 "2009-06-30T06:38:14Z")
> [@Sage\_Rat](#): > > So, firstly, explain why our modern era is 0.57C higher than the 1150-1200 period. Secondly, explain what has been causing the rise in temperature over the last 35 years if it isn’t the sun and volcanoes.) > [@Blake](#): > > An unknown process. > > I’ll say it again: You don’t need to accept my theory that the dark matter/energy discrepancy is caused by pixies just because you haven’t discovered an alternative explantion yet. A scientist isn’t required to accept an unscientific hypothesis just because she has no better alternative. That’s not how science works. An admission of ignorance is always acceptable in science, no alternative need be postulated. Wait a tick. How is your “unknown process” falsifiable? Or the admission of ignorance? ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [June 30, 2009, 6:44am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/108 "2009-06-30T06:44:34Z")
> [@Quartz](#): > > Umm… that’s not showing that the human emitted CO2 is **significantly** absorbing CO2. So you can show that that CO2 has different physical properties? > [@](#): > > I’ve expressed my lack of faith in models elsewhere. And I’d rather not wait 50+ years for results. More research is required! As mentioned before, models predicted the values and importance of the water vapor feedback. Confirmation came recently but many skeptics just close their eyes. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [June 30, 2009, 6:53am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/109 "2009-06-30T06:53:29Z")
> [@Quartz](#): > > I’ve expressed my lack of faith in models elsewhere. And I’d rather not wait 50+ years for results. More research is required! A good model should predict the future, starting from a historic date. Right now is 50 years in the future from sometime, and we know the starting conditions just fine from our recordings. Why wait 50 years when we can just predict now and see how close we get? Amazingly, that’s what we do. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 30, 2009, 7:17am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/110 "2009-06-30T07:17:55Z")
> [@Sage\_Rat](#): > > I have told you how to disprove it, way back on page 1 and again in my last post. And I explained in depth how this is not a method of disproving it at all. repeating the same proven nonsense doens’t make it true. > [@GIGObuster](#): > > How is your “unknown process” falsifiable? Or the admission of ignorance? It isn’t, what’s your point? I don’t think you actually read Popper’s article, did you? ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [June 30, 2009, 7:21am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/111 "2009-06-30T07:21:34Z")
> [@GIGObuster](#): > > So you can show that that CO2 has different physical properties? No, but just because it can do it doesn’t mean that it is doing it. And if it is, is it doing it to a significant degree? > [@](#): > > As mentioned before, models predicted the values and importance of the water vapor feedback. Cite? I was under the impression that this was built in to the models, so you cannot say that they predicted it. > [@](#): > > Confirmation came recently but many skeptics just close their eyes. I was clued in about water vapour feedback some years ago. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 30, 2009, 7:24am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/112 "2009-06-30T07:24:58Z")
> [@Sage\_Rat](#): > > Amazingly, that’s what we do. No, it isn’t. Models are calibrated to past temperatures. Using them to predict the same period of the past is perfectly circular. Of course they match. All the forcings and fine tunings were designed to make them match. Now if someone were to calibrate a model for 1900-2000 and then test it against 1800-1900 and get \>95% confidence you might have something. Or if someone constructed a model using only atmospheric composition data and physical constants without any reference to the temperature data. But at the moment all we’ve got is circular reasoning where we “test” models constructed as best fit to past temperature records by comparing how well they fit past temperature records. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [June 30, 2009, 7:55am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/113 "2009-06-30T07:55:43Z")
> [@Quartz](#): > > Cite? I was under the impression that this was built in to the models, so you cannot say that they predicted it. > > I was clued in about water vapour feedback some years ago. [http://www.sciencemag.org/cgi/content/short/310/5749/795](http://www.sciencemag.org/cgi/content/short/310/5749/795) > [@](#): > > General circulation models (GCMs) are highly sophisticated computer tools for modeling climate change, and they incorporate a large number of physical processes and variables. > > One of the most important challenges is to properly account for water vapor (clouds and humidity) in climate warming. In his Perspective, Cess discusses results reported in the same issue by Soden et al. in which water vapor feedback effects are tested by studying moistening trends in the upper troposphere. > > **Satellite observations of atmospheric water vapor are found to agree well with moisture predictions generated by one of the key GCMs, showing that these feedback effects are being properly handled in the model** , which eliminates a major potential source of uncertainty. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [June 30, 2009, 8:02am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/114 "2009-06-30T08:02:47Z")
> [@Blake](#): > > No, it isn’t. > > Models are calibrated to past temperatures. Using them to predict the same period of the past is perfectly circular. Of course they match. All the forcings and fine tunings were designed to make them match. > > Now if someone were to calibrate a model for 1900-2000 and then test it against 1800-1900 and get \>95% confidence you might have something. Or if someone constructed a model using only atmospheric composition data and physical constants without any reference to the temperature data. > > But at the moment all we’ve got is circular reasoning where we “test” models constructed as best fit to past temperature records by comparing how well they fit past temperature records. Testing them against recent volcano eruptions was still possible > [@](#): > > Given the absence of a few duplicate planets and some large time machines, we can’t test a 100-year temperature projection. Does that mean the models can’t be validated without waiting 100 years? No. > > The climate is an extremely complex system. Our observations of it are by no means complete – even with regard to what’s going on today. > > This is a shortcoming we need to work hard to correct, but it is also an opportunity for validating model predictions: Find a measurement we’ve never taken, see how the models say it should turn out, and then go take it and compare. > > Still, there are global temperature predictions that have been validated. We can start with one of the pioneers in climate science. Over 100 years ago, in 1896, Svante Arrhenius predicted that human emissions of CO2 would warm the climate. Obviously he used a much simpler model than current Ocean Atmosphere Coupled Global Climate models, which run on super computers. > > Arrhenius overestimated the climate’s sensitivity to CO2 by a factor of 2. At the same time, he hugely underestimated the degree of warming, assuming CO2 would rise very slowly (who could have predicted the emissions the future held?). Still, it was a pretty impressive early success for models. > > Running the clock forward: in 1988, James Hansen of NASA GISS fame predicted [PDF] that temperature would climb over the next 12 years, with a possible brief episode of cooling in the event of a large volcanic eruption. He made this prediction in a landmark paper and before a Senate hearing, which marked the official “coming out” to the general public of anthropogenic global warming. Twelve years later, he was proven remarkably correct, requiring adjustment only for the timing difference between the simulated future volcanic eruption and the actual eruption of Mount Pinatubo. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [June 30, 2009, 8:30am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/115 "2009-06-30T08:30:24Z")
> [@Blake](#): > > And I explained in depth how this is not a method of disproving it at all. Where? [Your response to my first post](http://boards.straightdope.com/sdmb/showpost.php?p=11247682&postcount=5) displays full acceptance of my falsifying criteria. You say, “I’m gonna do it!” And proceed to make a stab. The only problem is that your stab was a fantasy rather than data. If all the question there is to this thread is whether global warming is falsifiable, then the answer is yes. Both you and I agree that there is a way for you to disprove anthropogenic global warming. End of debate. BUT, if you want to move to the next step and actually falsify something, merely _supposing_ the existence of a natural, unknown source is meaningless. I can throw a ball through a vacuum, see that it’s following a parabola and _suppose_ that invisible aliens are moving it like that on a whim, rather than the theory of gravity is correct. But the ability to make such a supposition doesn’t disprove anything. I can propose ways to falsify gravity, but until I’ve got evidence to show it, I’m not doing anything but masturbating. But in summation, again: Yes, you can falsify AGW. Show that our understanding of the physical properties of greenhouse gases in the atmosphere is incorrect, and/or provide a working, **predictive** model of the Earth that explains what is going on better. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [July 1, 2009, 9:22pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/116 "2009-07-01T21:22:55Z")
**Blake** - I seem to be having some difficulty understanding where you’re coming from. You agree: 1. That GHGs retain extra heat. 2. That humans put extra GHGs in the atmosphere. 3. That we observe an increase in the Earth’s temperature that is of the right size counting both human GHGs and natural factors. If you agree with all three, it seems to me that you agree with AGW. If not, which of the three do you disagree with? > [@Blake](#): > > The others either also test alternative hypotheses. For example “Can the human-produced carbon dioxide (and other gases) retain extra heat in the atmosphere?” That’s not an alternative hypothesis. That’s a necessary component of AGW. Is GHGs don’t retain heat, AGW is dead. > [@Blake](#): > > Indeed this fact was resolved long before the AGW hypothesis was ever proposed and could never have been used to falsify AGW short of some serious re-rewriting of the laws of physic. It doesn’t matter **when** the IR absorbance of GHGs is discovered. Principles of physics are not numbers. 1. If you have a data set: 1, 2, 3, 4, 5… you can’t test the hypothesis that the next datum will be 6 using that data set. You need new data to falsify the hypothesis. 2. If you have: Boyle’s Law, Charles’ Law, and Avogadro’s Law, you can’t throw out Boyle’s Law and collect a new one because you want to test the Ideal Gas Law. You seem to be asking for us to do #1, when the situation is #2. Unless I’ve got you wrong - perhaps you could explain further? > [@Blake](#): > > But I will ask you yet again: what evidence can I collect that I can collect that will cause you to reject AGW? 1. Any evidence demonstrating that CO[sub]2[/sub] and other GHGs do not absorb heat. 2. Any evidence that the CO[sub]2[/sub] in the atmosphere does not come from fossil fuels. 3. Evidence that the sun’s intensity (e.g. TSI) has been increasing sufficiently to account for observed warming. 4. Evidence of sufficient volcanic action to account for observed warming. 5. Evidence that the amount of GHGs in the atmosphere does not account for observed warming. 6. Evidence of unexplained heat being brought into Earth from space of about the right amount to account for observed warming. 7. Evidence of unexplained heat being brought to the surface of Earth from within of about the right amount to account for observed warming. I would guess that your best bets are #3-7. ---
**Author:** ![Capt.Ridley\_s\_Shooting\_Party](https://avatars.discourse-cdn.com/v4/letter/c/cc9497/32.png) [@Capt.Ridley\_s\_Shooting\_Party](https://boards.straightdope.com/u/Capt.Ridley_s_Shooting_Party)\ **Post date:** [July 1, 2009, 11:00pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/117 "2009-07-01T23:00:09Z")
> [@Quartz](#): > > I’ve expressed my lack of faith in models elsewhere. And I’d rather not wait 50+ years for results. More research is required! Why do you have a lack of faith with models? Is it all models you have a lack of faith with, or just climate models? Do you believe British nuclear weapons are duds, or will explode when they need to? What do you base this trust on? The computer models used to guarantee their detonation? ---
**Author:** ![Anduril](https://avatars.discourse-cdn.com/v4/letter/a/c0e974/32.png) [@Anduril](https://boards.straightdope.com/u/Anduril)\ **Post date:** [July 1, 2009, 11:03pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/118 "2009-07-01T23:03:01Z")
> [@wevets](#): > > **Blake** 1. Any evidence demonstrating that CO[sub]2[/sub] and other GHGs do not absorb heat. > 2. Any evidence that the CO[sub]2[/sub] in the atmosphere does not come from fossil fuels. > 3. Evidence that the sun’s intensity (e.g. TSI) has been increasing sufficiently to account for observed warming. > 4. Evidence of sufficient volcanic action to account for observed warming. > 5. Evidence that the amount of GHGs in the atmosphere does not account for observed warming. > 6. Evidence of unexplained heat being brought into Earth from space of about the right amount to account for observed warming. > 7. Evidence of unexplained heat being brought to the surface of Earth from within of about the right amount to account for observed warming. > > I would guess that your best bets are #3-7. I have a problem with your #1 and #2. Let’s say I have a theory that says that warts are caused by heat fairies who respond to the heat of the sun. Can I claim that that theory is falsifiable by showing that my theory is falsified if anybody can demonstrate that the sun is not a source of heat? Or that the majority of the heat we feel on earth doesn’t come from the sun? I know little about the rest, but I don’t think the first two items on your list contribute to showing that AGW is falsifiable. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [July 1, 2009, 11:31pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/119 "2009-07-01T23:31:21Z")
> [@Anduril](#): > > Can I claim that that theory is falsifiable by showing that my theory is falsified if anybody can demonstrate that the sun is not a source of heat? Or that the majority of the heat we feel on earth doesn’t come from the sun? I agree that #1 and 2 on my list are extremely unlikely for any new evidence to come to light. **Blake** would probably agree that they’re solid, but I can’t speak for him/her. **Quartz** , on the other hand, suggests in post #66 that #1 would be a place to check for falsification. The other thing is falsifiability is a **philosophical** concept. It doesn’t matter that we’re extremely confident that CO[sub]2[/sub] absorbs at 13-15 μm, **falsifiability** (see the references to Karl Popper earlier in the thread) is about **whether that value can be measured or not** , not about whether we think the measurements that have already been made are accurate or not. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 2, 2009, 2:17am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/120 "2009-07-02T02:17:46Z")
> [@Blake](#): > > Except that it does. Most models incorporate tree ring data. Either it turns out that they don’t match temperature and improve model fit anyway, or they do match the temperature and the models are wrong. Neither option makes the modelling exercises look good. Are you claiming that global climate models incorporate tree ring data? How do they do that? I get the feeling that your idea of modeling is the sort of empirical fitting to parameters that you find it some fields. That is not how climate models work. They are based on physical principles and, while it is necessary to parametrize certain features (such as those of clouds) that occur at sub-grid length scales, the parameters that can be “tuned” are not very many and are usually constrained by either the physical process itself or some very basic issue such as the model maintaining a roughly constant global temperature in “control scenarios” (i.e., the absence of any net forcing). > [@](#): > > The cooling of the past 12 years will go exactly the same way, and we’ve already seen papers predicting 20 more years of cooling as a result of AGW, based on their preliminary models. First of all, I don’t think any of the temperature data sets…and almost certainly not either of the surface ones…shows a net cooling trend over the last 12 years. Even if one does, it would not if you went to 13 years or 11 years. (One can cherrypick a little bit by starting with the 1998 El Nino, which had a global temperature that was more than 2 standard deviations above the trendline.) Second of all, periods of cooling are simply not unexpected over such short periods (of years to about a decade or so) for a system that consists of a linear trend of ~0.015-0.02 C/yr but with year-to-year variability on top of that which is almost an order of magnitude higher…and any careful analysis of the trend lines that also includes the error bars on the trends (and these need to be calculated carefully because of correlations) shows these negative trends to lack statistical significance. The people who try to claim falsification of AGW based on negative trendlines over periods of less than about 15 years are not demonstrating Popperian falsification but rather just statistical ignorance. (See [here](http://tamino.wordpress.com/2009/06/26/embarrassing-questions/) for a discussion of this by “Tamino”, a blogger with wizardlike data and statistical analysis skills.) Third of all, there are thousands of papers published each year in climate science and the fact that there was one that predicted that we would have that ~20 more years of cooling within the context of a model that in general predicted warming due to AGW does not mean it represents the general consensus in the field. In fact, [that paper by Keenlyside et al. was met with considerable skepticism and plenty of people (myself included) who would be willing to wager that it’s prediction will be wrong](http://www.realclimate.org/index.php/archives/2008/05/the-global-cooling-bet-part-2/). As for the general issue of falsification, I don’t want to repeat what I said in the other current AGW thread, so I will just [link to it](http://boards.straightdope.com/sdmb/showpost.php?p=11295535&postcount=143). [Previous page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=5) [Next page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=7)