# 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:** 2
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 16, 2009, 11:15am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/21 "2009-06-16T11:15:31Z")
> [@Walker\_in\_Eternity](#): > > I suspect that a geologist and/or paleontologist will be along shortly to refute the other two as well. I’m not a geologist an I can point out that plate tectonics is [falsifiable](http://scienceblogs.com/highlyallochthonous/2008/06/earthquake_in_iceland.php). I have no idea where this odd notion came from that observational sciences don’t operate on falsifiability. I’ve worked in an observational science for many years and I’ve never operated on anything but falsifiability. just because I can’t see what plants an animals lived in an area before human disturbance that doesn’t mean I can’t falsify any hypotheses. I can make a prediction of what the pollen record of nearby sediments should show, or look at isotopes in the soil, or make a prediction about what I should find at undisturbed sites elsewhere. If any of those observations fail to match my predictions the hypothesis is falsified. And for the life of me I can’t see why palaeontology couldn’t make very similar predictions. The idea that palaeontology can’t produce falsifiable predictions seems incredible. ---
**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 16, 2009, 11:22am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/22 "2009-06-16T11:22:46Z")
> [@Half\_Man\_Half\_Wit](#): > > But AGW isn’t untestable … if there is no rise in temperature, there is no global warming, and hence, no _anthropogenic_ global warming. This is not correct: there may be cooling going on and mankind may be countering it, producing a nil net effect. Your statement shows how complex the matter is. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 16, 2009, 11:31am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/23 "2009-06-16T11:31:40Z")
> [@Half\_Man\_Half\_Wit](#): > > Well, we could try to reduce emissions, and see if temperatures rise anyway… Or we could continue to increase emissions and see if it fails to rise, as you said earlier. > [@](#): > > But AGW isn’t untestable like gods are: again, if there is no rise in temperature, there is no global warming, and hence, no _anthropogenic_ global warming. I’m afraid I don’t understand this. Are you saying that the only warming the Earth ever experiences is anthropogenic? > [@](#): > > And even the existence of gods (or the supernatural in general) would have to be taken into consideration if it turns out to be impossible to find another explanation. No, it certainly wouldn’t. There are a great many things that science can’t explain. We don’t incorporate a God of gaps. > [@](#): > > But what you actually are proposing is to accept having _no explanation_ in favour of an explanation _you don’t like_ It has nothing to do with what I like. it has to do with whether it is science. If you want to invoke a religious explanation or any other explanation that’s fine with me. It still doesn’t make it science. > [@](#): > > gods aren’t, as far as science is concerned, a possible explanation This is a total non sequitur. Science is something that is falsifiable. If AGW isn’t falsifiable then why is it any more science than gods? > [@](#): > > Any possible explanation (is automatically favoured over none at all; only if that explanation has been ruled out can one revert to a state of ignorance. Cite. Seriously, where is that in the Popperian definition of science? Any falsifiable explanation is science. If the explanation isn’t falsifiable it is ruled out as being science. Where does it say that you can accept unfalsifiable explanations as science so long as you have no replacement theory? > [@](#): > > The thing about AGW is that it’s such an eminently reasonable assumption to make Yes, just like the eminently reasonable assumption that the Earth is flat and that the sun orbits it. Or the eminently reasonable assumption that black people are less technologically advanced because they are closer to apes. In the entire history of the world has any eminently reasonable assumption actually been _correct_? I can’t think of any, but even if there have been a few the fact that so many have been proven false shows why science relies on falsifiablity, not eminent reaosnablenesss. ---
**Author:** ![Stanislaus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stanislaus/32/3391_2.png) [@Stanislaus](https://boards.straightdope.com/u/Stanislaus)\ **Post date:** [June 16, 2009, 11:56am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/24 "2009-06-16T11:56:58Z")
> [@Popper](#): > > At the same time I realized that such myths may be developed, and become testable; that historically speaking all — or very nearly all — scientific theories originate from myths, and that a myth may contain important anticipations of scientific theories. Examples are Empedocles’ theory of evolution by trial and error, or Parmenides’ myth of the unchanging block universe in which nothing ever happens and which, if we add another dimension, becomes Einstein’s block universe (in which, too, nothing ever happens, since everything is, four-dimensionally speaking, determined and laid down from the beginning). I thus felt that if a theory is found to be non-scientific, or “metaphysical” (as we might say), it is not thereby found to be unimportant, or insignificant, or “meaningless,” or “nonsensical.”[4] But it cannot claim to be backed by empirical evidence in the scientific sense — although it may easily be, in some genetic sense, the “result of observation.” When Popper speaks of ideas becoming testable, it suggests that the same hypothesis may move from “non-scientific” to “scientific” as our ability to falsify it develops. For example, Democritus proposed that all matter was created of indivisible particles, which he called atoms. My question is, was this a scientific theory? Or did it only become one thousands of years later, when we gained the ability to observe matter on the atomic scale? If AGW could only be falsifed by conducting some impossibly elaborate experiment or simulation which it was utterly beyond our current technical ability to actually do, would that make it non-scientific? There’s surely a difference between being non-falsifiable (i.e. not falsifiable under any circumstances) and unfalsifiable (i.e. not able to be falsified by any means at our disposal right now.) Also, Popper’s quote above would suggest that, should we conclude AGW was non-scientific, it could still very well be important, significant, meaningful and sensible. In which case, the right response may very well be to continue researching the climate with a view to a)refining the AGW hypothesis and/or b)improving our ability to falsify it. ---
**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 16, 2009, 12:07pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/25 "2009-06-16T12:07:03Z")
> [@Half\_Man\_Half\_Wit](#): > > But what you actually are proposing is to accept having _no explanation_ in favour of an explanation _you don’t like_; if that’s a way to do science, it’s a way that’s new to me. Remind me of your scientific credentials. Liking or not liking an explanation doesn’t come into it. There’s plenty of stuff for which we have no explanation. Sure we can invent hypotheses to explain them, but we don’t accept even the most plausible until they’re proven. In the interim, we accept that there is currently no explanation. > [@](#): > > The thing about AGW is that it’s such an eminently reasonable assumption to make The thing about AGW is that being a reasonable assumption does not make it correct. Newton’s Laws of Motion were reasonable - and were a tremendous achievement - and passed everyday tests; Einstein had to correct them. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 16, 2009, 12:23pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/26 "2009-06-16T12:23:26Z")
> [@amrussell](#): > > For example, Democritus proposed that all matter was created of indivisible particles, which he called atoms. My question is, was this a scientific theory? Or did it only become one thousands of years later, when we gained the ability to observe matter on the atomic scale? It was unscientific. A completely different theory with the same prediction was scientific at a later date. I can’t see how the fact that the two theories have the same prediction means they both have to be scientific. Genesis and evolution both predicted that humans would appear in the fossil record after all other species. Does that make genesis scientific? > [@](#): > > If AGW could only be falsifed by conducting some impossibly elaborate experiment or simulation which it was utterly beyond our current technical ability to actually do, would that make it non-scientific? What if we replace AGW in that sentence with “Astrology” or “Freudian Psychology” or “Christianity” or any other psuedosciene? Because the statement is no less true and no less nonsensical for such a change. > [@](#): > > There’s surely a difference between being non-falsifiable (i.e. not falsifiable under any circumstances) and unfalsifiable (i.e. not able to be falsified by any means at our disposal right now.) If there is such a difference then we will have to concede Astrology or Freudian Psychology and Christianity are also unfalsifiable. And if we accept that, then precisely what utility do you see in distinguishing between unfalsifiable and non-falsifiable? > [@](#): > > Also, Popper’s quote above would suggest that, should we conclude AGW was non-scientific, it could still very well be important, significant, meaningful and sensible. In which case, the right response may very well be to continue researching the climate with a view to a)refining the AGW hypothesis and/or b)improving our ability to falsify it. True enough. However what it _doesn’t_ suggest is that we must or even should do so. Most unfalsifiable theories are invalid and useless. Some, as Popper notes, are not. So while we shouldn’t discount all theories because they are unscientific that doesn’t mean that we have to accept them all either. They laughed at Newton and they laughed at Columbus but they also laughed at Bozo the Clown. ---
**Author:** ![Stanislaus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stanislaus/32/3391_2.png) [@Stanislaus](https://boards.straightdope.com/u/Stanislaus)\ **Post date:** [June 16, 2009, 1:02pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/27 "2009-06-16T13:02:01Z")
> [@Blake](#): > > It was unscientific. A completely different theory with the same prediction was scientific at a later date. I can’t see how the fact that the two theories have the same prediction means they both have to be scientific. > > Genesis and evolution both predicted that humans would appear in the fossil record after all other species. Does that make genesis scientific? I’d query, given that Genesis flatly contradicts the possibiliity of a fossil record, whether it predicts any such thing. But we’ve been given the criterion for “scientific-ness” - making falsifiable predictions. If you assure me that Genesis does make such a prediction, then I will agree that it is scientific. I wouldn’t want to be accused of picking and choosing what is science based on my own irrational prejudices. > [@](#): > > What if we replace AGW in that sentence with “Astrology” or “Freudian Psychology” or “Christianity” or any other psuedosciene? Because the statement is no less true and no less nonsensical for such a change. Again, I’d query the idea that Astrology doesn’t make predictions - I’d have said that it made pretty obvious predictions which were easily disproven. But that’s beside the point - Christianity, to pick another example, doesn’t make any predictions that could theoretically be proven with suitably advanced techonology - it’s metaphysical in essence. Similarly, I’m unaware of any claims that Freudian Psychology could be proven if only we had sufficiently advanced brain scanning equipment. By contrast, it seems to me - and I’m open to correction - that AGW could in theory be falsified: that with hugely powerful computers, a rigorous understanding of all the factors that influence climate and super-sensitive measuring equipment, it could be shown that the release of GHGs by humans had the effect of warming the planet over and above what it would be under “natural” conditions, _or not_. Does the fact that we cannot do this _now_ mean that AGW is in the same class as Christianity as a theory? In fact, here’s a thought experiment. Say that, in the year 2154, mankind will have developed the technology and understanding to falsify the current AGW theory by means of experiment. In what year does AGW become science? > [@](#): > > If there is such a difference then we will have to concede Astrology or Freudian Psychology and Christianity are also unfalsifiable. And if we accept that, then precisely what utility do you see in distinguishing between unfalsifiable and non-falsifiable? I disagree entirely. As above, I would say that Christianity is non-falsifiable in essence - there is no even theoretical experiment that would prove or disprove Christ’s claim to be the Way, the Truth and the Life. Whereas, for example, if I went back in time to, say, 1689 and presented Huygens with the theoretical basis for GR, that would merely be unfalsifiable - Huygens would be unable to make sufficiently accurate measurements to test the theory, owing solely to the paucity of his equipment. Does that make the difference clearer? > [@](#): > > True enough. However what it _doesn’t_ suggest is that we must or even should do so. Most unfalsifiable theories are invalid and useless. Some, as Popper notes, are not. So while we shouldn’t discount all theories because they are unscientific that doesn’t mean that we have to accept them all either. They laughed at Newton and they laughed at Columbus but they also laughed at Bozo the Clown. Hmm. Saying, “Other unfalsifiable theories were useless, therefore this one is useless” strikes me as a somewhat fallacious decision-making process. ---
**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 16, 2009, 2:53pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/28 "2009-06-16T14:53:55Z")
> [@Blake](#): > > And I repeat Popper: it is easy to obtain confirmations, or verifications, for nearly every theory — if we look for confirmations. This apparent strength was in fact their weakness That really sounds like grasping at straws. The fact is that the water vapor feedback was pointed as important for the Greenhouse gas theory to work, [deniers on the Straight Dope](http://boards.straightdope.com/sdmb/showpost.php?p=10999926&postcount=20) even told us that the water vapor feedback was not demonstrated as it was mostly coming from the physical computer models. Had the new tests and satellite data (yes, a satellite was launched also to get data to confirm the results of the mostly theoretical experiments until then) had demonstrated that the water vapor feedback with CO2 was hooey then a huge component of the prediction models and the theory behind AGW would have gone up in smoke. [http://www.sciencedaily.com/releases/2009/02/090219152132.htm](http://www.sciencedaily.com/releases/2009/02/090219152132.htm) > [@](#): > > But I never referenced the conclusions. I referenced a single, accurate figure. > > So can you please stop hijacking my thread. It is still bad science. Starting his graph from 2001 or 2002 does not make much a difference in the fact that he is being misleading. > **[RealClimate: Monckton’s deliberate manipulation](https://www.realclimate.org/index.php/archives/2009/05/moncktons-deliberate-manipulation/)** > > RealClimate: Our favorite contrarian, the potty peer Christopher Monckton has been indulging in a little aristocratic artifice again. Not one to be constrained by mere facts or observable reality, he has launched a sally against Andy Revkin for... > [@](#): > > Our favorite contrarian, the potty peer Christopher Monckton has been indulging in a little aristocratic artifice again. Not one to be constrained by mere facts or observable reality, he has launched a sally against Andy Revkin for reporting the shocking news that past industry disinformation campaigns were not sincere explorations of the true uncertainties in climate science. > > The letter he has written to the NY Times public editor, with its liberal sprinkling of his usual pomposity, has at its heart the following graph: > > Among other issues, it is quite amusing that Monckton apparently thinks that; > > ``` > * trends from January 2002 are relevant to a complaint about a story discussing a 1995 report, > * someone might be fooled by the cherry-picked January 2002 start date, > * no-one would notice that he has just made up the IPCC projection curves > > ``` > > The last is even more amusing because he was caught out making stuff up on a slightly different figure just a few weeks ago. > > To see the extent of this chicanery, one needs only plot the actual IPCC projections against the observations. This can be done a number of ways, firstly, plotting the observational data and the models used by IPCC with a common baseline of 1980-1999 temperatures (as done in the 2007 report) (Note that the model output is for the annual mean, monthly variance would be larger): > > These show clearly that 2002-2009 is way too short a period for the trends to be meaningful and that Monckton’s estimate of what the IPCC projects for the current period is woefully wrong. Not just wrong, fake. ---
**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 16, 2009, 2:59pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/29 "2009-06-16T14:59:44Z")
> [@Walker\_in\_Eternity](#): > > Why put the Lord in quotes? He’s a Viscount and as far as I can tell his title is legitimate. It seems to me that that is doubtful, like his work. [http://scienceblogs.com/deltoid/2009/05/monckton\_caught\_making\_things.php](http://scienceblogs.com/deltoid/2009/05/monckton_caught_making_things.php) > [@](#): > > ``` > With his latest shenanigans in the US, Monkton managed to catch the attention of Private Eye (a satirical current affairs magazine in the UK). > > In the latest issue 1235, they noted several things (quite apart from his dodgy science). > > One is his reference to himself as "a member of the Upper House of the United Kingdom legislature" in a letter to two American senators. He is not of course and never has been. As Private Eye notes: "Since inheriting the title, Christopher has stood at a "by-election" for a hereditary Tory seat in the Lords, following the death of Lord Mowbray and Stourton two years ago. He received precisely zero votes." > > The other thing Private Eye notes is his logo, which he is using on his graphs and letters - a portcullis topped with a crown, bearing a striking resemblance to the insignia of the House of Parliament. This is also very dodgy indeed as the official parliamentary guide states very clearly that "the usage of the crowned portcullis was formally authorised by Her Majesty the Queen for the two Houses unambiguously to use the device and thus to regulate its use by the others. The emblem should not be used for purposes to which such authentication is inappropriate, or where there is a risk that its use might wrongly be regarded, or represented as having the authority of the House". > > ``` ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [June 16, 2009, 3:05pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/30 "2009-06-16T15:05:03Z")
> [@Blake](#): > > Did you miss where I said that i didn;t want to debate Popperian science? Nope. > [@](#): > > And did you miss where I said that I am an observational scientist: an ecologist. Nope, did you miss the part of my post where I pointed out you were an ecologist and so was therefore puzzled as to the way you set up your definitions? > [@](#): > > And did you miss where Popper used an example from astrophysics (gravitational lensing) to defend GR as being good science Yup, could you point me to it? I did a google search for “Karl Popper” “gravitational lensing” and I’m not coming up with anything interesting. I’d be interested to read this but I have a rough ideal of what it would say. > [@](#): > > Let me assure you that Popperian science works perfectly in ecology, geography and astrophysics at least. I’d like you to expand about this. There are different kinds of observational sciences and Popper’s definition works to some extent for some of them. Some observational sciences generate so much data that scientists can afford to just patiently wait until the universe provides an experiment which they would have run anyway. In which case, Popperian criterion works much as they would for an experimental science. Some observational sciences generate a steady stream of data but there are systematic biases that can never be accounted for. AGW is one of these because we only have one earth to experiment, in which case, Popper is useful for the aspects of the theory that don’t depend on unique features of the earth. Some observational sciences work from a fixed set of data that can never be expanded upon in which case Popper’s criterion is wholly useless. > [@](#): > > But that’s OK. You’ve admitted that AGW isn’t falisfiable by definition. Next thread we can debate whether it’s science at all. Yes, I’ve admitted that AGW falls into the set of non-falsifiable theories that includes astrology, astronomy, paleontology, cryptozoology, geography, exobiology & religion. Now the question is, how is this a useful set? The reason I dispute your premise is because I think you’ve set it up to generate an ultimately uninteresting answer. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [June 16, 2009, 3:48pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/31 "2009-06-16T15:48:09Z")
> [@Quartz](#): > > This is not correct: there may be cooling going on and mankind may be countering it, producing a nil net effect. Just how likely do you think that the random amount of warming we have introduced happens to exactly counterbalance the random amount of cooling that occurs naturally by an as yet unknown process for which there exists zero evidence? And how scientific do you think this hypothesis is? > [@Blake](#): > > Or we could continue to increase emissions and see if it fails to rise, as you said earlier. Yes, both possible avenues for falsification. However, it’s not just dispassionate science we’re doing here, unfortunately, if worst comes to worst, there may be human lives at stake. > [@](#): > > I’m afraid I don’t understand this. Are you saying that the only warming the Earth ever experiences is anthropogenic? Actually, I said that if there’s no warming at all, there can surely be no anthropogenic warming. Sorry if that wasn’t clear. > [@](#): > > No, it certainly wouldn’t. There are a great many things that science can’t explain. We don’t incorporate a God of gaps. Great! I wasn’t arguing for a god of the gaps (and I hate the argument with a passion). However, if all natural explanations have been excluded (however epistemologically difficult or impossible that may be), then supernatural ones are all that remain. > [@](#): > > It has nothing to do with what I like. it has to do with whether it is science. If you want to invoke a religious explanation or any other explanation that’s fine with me. It still doesn’t make it science. Then why that need to equate AGW with religion in such a straw man way? If you were truly arguing from a scientific viewpoint an in the interest of such a viewpoint, you could assess the hypothesis on its merits and reach a conclusion without much fuss; heck, you could even conclude that climate studies are not an area worthy of your scientific attention and do whatever the heck else you want. > [@](#): > > This is a total non sequitur. > Science is something that is falsifiable. If AGW isn’t falsifiable then why is it any more science than gods? You’re mixing two things up here: first, I do consider AGW to be falsifiable, and you seemed to agree with the falsification scenarios I drew up. Second, as I said in [this post](http://boards.straightdope.com/sdmb/showpost.php?p=11247939&postcount=20), the question is ultimately a purely academic one anyway – what matters is whether it’s real or not, and whether you (or I or whoever else) choose to call it science or not does not impinge on that question in the slightest. Indeed, I’d be happy to renounce the scientific nature of AGW once and for all and have everybody shot who so much as dares to use the two words in one sentence if that meant we could just sit down and work out whether or not there’s a danger, how big it is, and what the best course of action is going to be; the moniker is wholly irrelevant to me. > [@](#): > > Cite. Seriously, where is that in the Popperian definition of science? It’s not in Popper’s essay because that was not what he concerned himself with in it; he merely establishes falsification as a necessary criterion for calling a theory scientific, however, I doubt he would have claimed that in doing so he had exhaustively circumscribed the whole area of scientific inquiry. However, I’m curious as to what it is you would have me cite – that in order to do science, one needs to _consider_ the hypotheses formulated to explain the empirical data before dismissing them? Honestly? > [@](#): > > Any falsifiable explanation is science. If the explanation isn’t falsifiable it is ruled out as being science. Where does it say that you can accept unfalsifiable explanations as science so long as you have no replacement theory? Well, I don’t hold AGW to be unfalsifiable, since it does make clear predictions about the future – indeed, it is nothing but a prediction about the future! (And can an explanation even be truly an explanation if it’s not falsifiable? Seems to me that ‘god did it’-like statements never actually explain anything so much as accept the unknowable nature of the true explanation; but that’s largely beside the point.) > [@](#): > > Yes, just like the eminently reasonable assumption that the Earth is flat and that the sun orbits it. Or the eminently reasonable assumption that black people are less technologically advanced because they are closer to apes. All of which was eventually supplanted by better models, none of which was ‘something unknown is doing we don’t know what’. I am happy to follow a climate model in better accord with the data up to this point, or in some other way preferable. Discarding the by a wide margin only reasonable model we have in favour of ignorance because of some philosophical quibble regarding the proper definition of the word ‘science’ runs counter to any sensible understanding of it. > [@Quartz](#): > > Remind me of your scientific credentials. :rolleyes: Please. Weighing our respective degrees against each other isn’t going to settle the argument one way or the other. (And if that _were_ the case, AGW would nowadays be considered an established fact.) > [@](#): > > Liking or not liking an explanation doesn’t come into it. There’s plenty of stuff for which we have no explanation. Sure we can invent hypotheses to explain them, but we don’t accept even the most plausible until they’re proven. In the interim, we accept that there is currently no explanation. Funny how you call my credentials into question and then go on to talk about proving things in science. What has ever been _proven_ in science? There are always only candidate explanations with varying levels of evidence speaking for them; as things are, our candidate explanations regarding the development of the climate are 1) AGW and 2) I dunno, them things just happen. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [June 16, 2009, 4:07pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/32 "2009-06-16T16:07:43Z")
I’m a total layman, so I can’t possibly contribute productively to these debates. I do have a question, though. **Blake** , what evidence would falsify the hypothesis that global warming is not caused by humans? ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [June 16, 2009, 4:21pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/33 "2009-06-16T16:21:09Z")
Or consider this analogy: An asteroid is headed to intersect Earth’s orbit. Due to some quirk in its orbit, or maybe the insufficient nature of our means (picture tech some 50 years ago), it is impossible to predict with absolute certainty whether we’ll get it, or it’ll be a near miss; some say it’ll hit, some say it won’t. With a concerted global effort, we could probably avert a possible collision, or perhaps not. This is analogous to the situation with AGW: maybe it’s coming, maybe it ain’t; maybe we can do something about it, maybe we can’t, and in both cases, it’s impossible to know for sure until ‘after the fact’. Would you now judge the hypothesis that the asteroid might hit us ‘unscientific’? And would your recommended course (whichever it might be) of action depend in any way on this judgement? ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 16, 2009, 5:18pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/34 "2009-06-16T17:18:44Z")
Although I have little doubt that humans are having an effect on the climate, the Medieval Warm Period occurred with no significant human input. GIGObuster: there is absolutely no doubt that Christopher Walter Monckton, is indeed 3rd Viscount Monckton of Brenchley. NONE. He is not a member of the current House of Lords, true but that doesn’t mean he is not a Viscount and thus Lord Monckton. ---
**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 16, 2009, 5:39pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/35 "2009-06-16T17:39:40Z")
> [@DrDeth](#): > > Although I have little doubt that humans are having an effect on the climate, the Medieval Warm Period occurred with no significant human input. > > GIGObuster: there is absolutely no doubt that Christopher Walter Monckton, is indeed 3rd Viscount Monckton of Brenchley. NONE. He is not a member of the current House of Lords, true but that doesn’t mean he is not a Viscount and thus Lord Monckton. Monckton clearly is trying to pass himself as a member of the house of lords, when his lordship is only because of \*\*who \*\*his relatives were that does diminish any authority that he claims. But more importantly his latest claims were made by making underhanded moves to convince others that he was being respected in academia, he is not. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 16, 2009, 5:49pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/36 "2009-06-16T17:49:33Z")
> [@GIGObuster](#): > > Monckton clearly is trying to pass himself as a member of the house of lords, when his lordship is only because of \*\*who \*\*his relatives were that does diminish any authority that he claims. > > t. No, he protesting how the new House of Lords is selected. In any case, member of the House of Lords or not, he’s still Lord Monckton. ---
**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 16, 2009, 6:02pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/37 "2009-06-16T18:02:40Z")
> [@DrDeth](#): > > Although I have little doubt that humans are having an effect on the climate, the Medieval Warm Period occurred with no significant human input. > **[Climate myths: It was warmer during the Medieval period, with vineyards in...](https://www.newscientist.com/article/dn11644-climate-myths-it-was-warmer-during-the-medieval-period-with-vineyards-in-england/)** > > Temperature over the past 1000 years See all climate myths in our special feature. English wine production is once again thriving and the extent of the country's vineyards probably surpasses that in the so-called Medieval Warm Period . So if you... > [@](#): > > Climate myths: It was warmer during the Medieval period, with vineyards in England > > … > > In the southern hemisphere, the picture is even more mixed, with evidence of both warm and cool periods around this time. The Medieval Warm Period may have been mostly a regional phenomenon, with the extremes reflecting a redistribution of heat around the planet rather than a big overall rise in the average global temperature. > > What is clear, both from the temperature reconstructions and from independent evidence - such as the extent of the recent melting of mountain glaciers - is that the planet has been warmer in the past few decades than at any time during the medieval period. In fact, the world may not have been so warm for 6000 or even 125,000 years (see Climate myths: It has been warmer in the past, what’s the big deal?). > > What really matters, though, is not how warm it is now, but how warm it is going to get in the future. Even the temperature reconstructions that show the greatest variations in the past 1000 years suggest up until the 1980s, average temperature changes remained within a narrow band spanning 1ºC at most. Now we are climbing out of that band, and the latest IPCC report (pdf format) predicts a further rise of 0.5ºC by 2030 and a whopping 6.4ºC by 2100 in the worst case scenario. ---
**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 16, 2009, 6:03pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/38 "2009-06-16T18:03:52Z")
> [@DrDeth](#): > > No, he protesting how the new House of Lords is selected. In any case, member of the House of Lords or not, he’s still Lord Monckton. Lord in the family sense, and nothing else, regardless of what he pretends to be. I would not have a beef if it wasn’t for the fact that he is making an effort to pass himself as a member of the house. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [June 16, 2009, 6:23pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/39 "2009-06-16T18:23:25Z")
> [@Blake](#): > > I’m not a geologist an I can point out that plate tectonics is [falsifiable](http://scienceblogs.com/highlyallochthonous/2008/06/earthquake_in_iceland.php). > > I have no idea where this odd notion came from that observational sciences don’t operate on falsifiability. I’ve worked in an observational science for many years and I’ve never operated on anything but falsifiability. just because I can’t see what plants an animals lived in an area before human disturbance that doesn’t mean I can’t falsify any hypotheses. I can make a prediction of what the pollen record of nearby sediments should show, or look at isotopes in the soil, or make a prediction about what I should find at undisturbed sites elsewhere. If any of those observations fail to match my predictions the hypothesis is falsified. > > And for the life of me I can’t see why palaeontology couldn’t make very similar predictions. The idea that palaeontology can’t produce falsifiable predictions seems incredible. My claim is not that all observational science is unfalsifiable but that there exists claims in observational science which are unfalsifiable. Consider Jared Diamond’s reporting of Barry Rolett’s claim in [page 115-118](http://books.google.com/books?id=QyzHKSCYSmsC&pg=PA115) of Collapse. Rolett looked at the degree of deforestation on 81 polynesian islands and came up with a model for deforestation that involved 9 different variables. Is his hypothesis true? Who knows? Is it scientific? I would argue that it is. Is it falsifiable? Hell no. How would you falsify a claim like that? It’s not like you can generate an 82nd island to test the model. The entire sum of the dataset for all eternity is going to be 81 islands. Given that there’s an infinite number of models that would explain such data, how can we be sure Rolett’s 9 factor one is the correct one? ---
**Author:** ![Public\_Animal\_No.9](https://avatars.discourse-cdn.com/v4/letter/p/b9e5f3/32.png) [@Public\_Animal\_No.9](https://boards.straightdope.com/u/Public_Animal_No.9)\ **Post date:** [June 17, 2009, 1:14am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/40 "2009-06-17T01:14:52Z")
The key question that would have to be shown to be falsifiable, IMHO, is what is cause and what is effect. We can easily demonstrate whether or not increases in greenhouse gases change the radiative properties of air to retain more radiative energy. We can demonstrate whether emissions of those gases are anthropogenic. We can demonstrate the effects of water vapor or clouds. What the key issue is, then, is whether the increases in greenhouse gases cause warming or whether warming causes increases in greenhouse gases. It may be my ignorance of the science of natural processes, but the latter cause-effect relationship seems to me to be the more difficult one to demonstrate. For the former, we can (and have) estimated the amount of GHGs generated through (primarily) combustion of fossil fuels, and from other anthropogenic sources, and we have a pretty good handle on how those gases influence the radiative properties of air. This was done well over 100 years ago by Arrhenius, who was the first to suggest that the climate could be altered by fossil fuel use. The ease of demonstrating a hypothesis (at least theoretically) does not lead to a conclusive answer, given the real-world complexities. Nor does the difficulty of demonstrating a competing hypothesis disprove that theory. But for me, the first step in falsifying AGW is to demonstrate that the increased anthropogenic emissions of greenhouse gases does not result in changes to the atmosphere’s radiative balance. Most of what I’ve seen about this from the skeptics leans on complex natural processes to counteract any warming effect - to my mind, they seem to agree that increased GHG concentrations would result in a warming tendency, since I have not seen anything that contradicts that basic relationship (such a contradiction may be out there, I just haven’t seen it). But much more often, the arguments tend to be about which is cause and which is effect. I tend to side with those that say we will have to wait to find out conclusively. There may be ways to demonstrate which it is, but in the meantime, the first steps we would take to reduce emissions have other major benefits, such as more efficient use of energy and reducing our reliance on unstable energy sources (oil). By the time we’re ready to really implement any major carbon reduction approaches, like capturing and storing CO2, our understanding of the atmospheric dynamics will have improved, perhaps to the point where it’s exceedingly clear what the causes and effects are. It would be nice to be able to say that we would have “undeniable” evidence, but there will always be those who will deny anything that leads to a conclusion they don’t like. [Previous page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=1) [Next page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=3)