# 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:** 4
**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 17, 2009, 7:45pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/61 "2009-06-17T19:45:15Z")
> [@xtisme](#): > > I hesitate to ask this question as I don’t want to get my head bit off, but why wouldn’t a reverse in the warming trend (or current temperature plateau) falsify the AGW theory? Let’s say we go into another cooling phase similar to the Little Ice Age. If this happened despite the continued rise in CO2, wouldn’t that falsify the theory? If not, then why not? > > -XT It would depend. The AGW theory simply states that there is a greenhouse effect which can be increased or decreased by humans. It doesn’t say that there’s no other factors in the universe that could possibly effect the global climate. There most certainly are other things factoring into the climate and changing any of those will most certainly change where things are. That doesn’t disprove the greenhouse effect since you’re not modifying anything that has to do with greenhouse gases. If you can show that our understanding of the physical nature of the molecules and elements making up the greenhouse layer are different than we currently understand them to be, -that- would certainly be a thunker. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [June 17, 2009, 8:49pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/62 "2009-06-17T20:49:15Z")
Hopefully getting the thread back on track… Hi **Blake** – I’m a little surprised to see claims of unfalsifiability directed at AGW. How is it different from theories of tornado formation or oceanic circulation? ``` **1. First falsifiable test of AGW:** ``` Can the human-produced carbon dioxide (and other gases) retain extra heat in the atmosphere? The answer to this question is clearly yes, but it could have been no. If the asymmetric stretch absorption CO[sub]2[/sub] were in the range 2-3 μm instead of around 4 μm and 13-15 μm, it would not be a greenhouse gas (the Earth emits thermal IR in the range 6-30 μm or so) and AGW would have been falsified. It is a result that meets your criteria: 1. It is replicable 2. It would lead to AGW being rejected 3. Actually, I don’t know enough about chemistry to know if it is subject to a statistical test. I suspect your #3 requirement is inappropriate for the wavelengths of IR that CO[sub]2[/sub] absorbs. Could you elaborate on whether you accept these measurements despite the fact that they are not a statistical test? I would guess that the error values for the measurements would suffice, wouldn’t you? But as you mention, it’s not really enough that we know that. We need more information… **2. Second falsifiable test of AGW** Are the burning of fossil fuels and other human activities the source of the additional GHGs in the atmosphere? Luckily, we can trace our own input of carbon due to the fact that fossil fuels have a slightly different isotope ratio of [sup]12[/sup]C to [sup]13[/sup]C than modern carbon found in the atmosphere. We can trace the isotope ratios of carbon in ocean and atmosphere, and discover that the additional signal of anthropogenic carbon is detectable: > [@Quay et al. 2003](#): > > Measurements of the ocean-wide ∂[sup]13[/sup]C distribution during the 1990s significantly improved the determination of the ocean ∂[sup]13[/sup]C changes that have occurred due to the uptake of anthropogenically produced CO[sub]2[/sub]. These new data indicate that the global mean rate of ∂[sup]13[/sup]C inventory change was -65 ± 33 ‰ m per decade between the 1970s and 1990s. Between 1970 and 1990, the ocean-wide surface ∂[sup]13[/sup]C decrease rate of -0.16 ± 0.02 ‰ per decade represents about 70% of the measured atmospheric ∂[sup]13[/sup]C decrease over the same period [Francey et al., 1999]. Citation: Quay et al. 2003. Changes in the [sup]13[/sup]C/[sup]12[/sup]C of dissolved organic carbon in the ocean as a tracer of anthropogenic CO[sub]2[/sub] uptake. _Global Biogeochemical Cycles_ Vol. 17, No. 1. (N.B. ∂[sup]13[/sup]C is negative in these measurements because fossil fuels have more [sup]12[/sup]C than [sup]13[/sup]C. Plants preferentially take up [sup]12[/sup]C over the heavier isotopes of C.) > [@Chen and Drake 1986](#): > > Using carbon isotopic ratios in tree rings and comparing them with atmospheric ratios and those of fossil fuel, Stuiver at al (1984) calculated that for the period between 1600 and 1975, the biota released to the atmosphere as much carbon (149 x 10[sup]15[/sup] g) [note from wevets: carbon released from human-caused deforestation and land clearing is also anthropogenic] as did fossil fuel combustion (135 x 10[sup]15[/sup] g). Approximately half this total amount has been transferred to the oceans. As was mentioned earlier, the difficulties in using carbon isotopic ratios in tree rings for such calculations causes a large uncertainty factor, and efforts to reforest the cleared land and the potential enhanced photosynthesis due to the excess CO[sub]2[/sub] are all important factors that offset to a degree the effect of large-scale deforestation. Depending on the period of history under consideration, deforestation could contribute either more or less to the CO[sub]2[/sub] production than does fossil fuel consumption, but the biota still appears to be a net source of CO[sub]2[/sub] (Woodwell 1983). > > The latest estimates of Broecker and his colleagues (Peng et al 1983, 1984), based on further study of the tree-ring [sup]13[/sup]C record, show that the input of [sup]13[/sup]C-depleted CO[sub]2[/sub] from deforestation and soil decomposition increased from 1800 to 1860, and since then has been slowly declining with respect to the contribution from fossil fuel. During the two-decade period of the Mauna Loa record the forest-soil input has been about 20% of that from fossil fuel, a level not considered by those authors as contributing significantly to the secular increase in atmospheric CO[sub]2[/sub]. Citation: [Carbon dioxide increase in the atmosphere and oceans and possible effects on climate](http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1986AREPS..14..201C&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf). 1986. _Annual Reviews of Earth and Planetary Science_ – It’s an old article, but I’m not spending more time at the moment searching for a new one, feel free to update with newer figures if you desire. 1. It is replicable 2. It would lead to AGW being rejected if the anthropogenic carbon were found to not remain in the atmosphere. 3. Again, I don’t think the one statistical test notion applies here. Would you accept the confidence interval of the carbon measurements instead? There are some people who would say that this is really all you need to know – no one disputes that humans burn large amounts of fossil fuels, that the combustion products go into the atmosphere, and that works to retain heat. But to really give AGW another falsifiable test, why don’t we test it against other theories of what could change the temperature of the globe on average? **3. Third falsification test of AGW** This one’s a little different from the others, in that it’s actually not a falsification of AGW – rather a falsification of an alternative hypothesis, that solar irradiance changes explain the changes in temperature. How do we know the sun’s not just heating up the Earth more? Fortunately, we can measure TSI, Total Solar Irradiance, and find out if that has changed. > [@Foukal et al. 2006](#): > > Variations in the Sun’s total energy output (luminosity) are caused by changing dark (sunspot) and bright structures on the solar disk during the 11-year sunspot cycle. The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years. > > … > > Overall, we can find no evidence for solar luminosity variations of sufficient amplitude to drive significant climate variations on centennial, millennial, and even million-year timescales. Citation: Foukal et al. 2006. Variations in solar luminosity and their effect on the Earth’s climate. Nature v. 443, pgs. 161-166. 1. It is replicable 2. It would lead to AGW being rejected if TSI were found to be large enough to account for the observed changes in temperature. 3. Again, I’m not sure the “single statistical test” idea applies here – what test would you perform? **4. Fourth falsification test of AGW** Again, a falsification of an alternative hypothesis, that volcanic action explains the changes in temperature. > [@United States Geological Survey](#): > > Our studies show that globally, volcanoes on land and under the sea release a total of about 200 million tonnes of CO2 annually. > This seems like a huge amount of CO2, but a visit to the U.S. Department of Energy’s Carbon Dioxide Information Analysis Center (CDIAC) website ([http://cdiac.ornl.gov/](http://cdiac.ornl.gov/)) helps anyone armed with a handheld calculator and a high school chemistry text put the volcanic CO2 tally into perspective. Because while 200 million tonnes of CO2 is large, the global fossil fuel CO2 emissions for 2003 tipped the scales at 26.8 billion tonnes. Thus, not only does volcanic CO2 not dwarf that of human activity, it actually comprises less than 1 percent of that value. Citation: [Hawaiian Volcano Observatory](http://hvo.wr.usgs.gov/volcanowatch/2007/07_02_15.html) 1. It is replicable 2. It would lead to AGW being rejected if volcanic emissions of GHGs were large enough to account for the observed changes in temperature. 3. Again, I’m not sure the “single statistical test” idea applies here – what test would you perform? **But wevets, tests #3 and #4 are not tests of AGW, they just test alternate hypotheses! You can’t declare AGW correct just because an alternate fails!** True, but if you eliminate the alternate hypotheses, the un-eliminated plausible hypothesis becomes increasingly attractive (implausible hypotheses remain unattractive.) Deduction is not a frequent pillar of Popperian philosophies of science, but that does not make it less effective a tool of logic. There may be some undiscovered factor that could be tested against AGW, and that’s fine. But we don’t put everything on hold until all the undiscovered things are discovered, because that will literally never happen. **5. Fifth falsification test of AGW** Is the amount of anthropogenic GHGs sufficient to account for the observed warming? This is the only one I’ll turn to models for… > [@Crowley 2000](#): > > One way to highlight the unusual nature of the late-20th-century warmth is to subtract all forcing other than CO[sub]2[/sub] (solar, volcanism, and tropospheric aerosols) and examine the late-20th-century residuals within the context of the previous 1000 years (Fig. 6). There is an unprecedented residual warming in the late 20th century that matches the warming predicted by GHG forcing. Citation: [Causes of climate change over the past 1000 years](http://web.ebscohost.com/ehost/detail?vid=1&hid=7&sid=014e8a12-588c-4b59-8643-8e5ca040f032%40sessionmgr2&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=ehh&AN=3383020) by Crowley, 2000 in _Science_. 1. These calculations are replicable 2. It would lead to AGW being rejected if GHGs were insufficient to account for the observed changes in temperature or would cause much larger changes in temperature than observed. 3. This one actually is amenable to statistical tests – those are elaborated on in the linked paper. I think part of the problem here is that I would disagree with your definition of AGW, **Blake**. I would define AGW theory as stating: **Human emissions of greenhouse gases have the potential to increase the Earth’s average temperature and change the general state of Earth’s climate.** This appears to differ from your definition of AGW, since you’ve alluded to **specific** predictions or models of **how much** temperature would rise as AGW. I completely reject the notion that future models are a test of the falsifiability of AGW (note that I have used models calculated about the past as a falsifiability test in the ballpark sense.) I also completely reject the notion that models **are AGW**. Models are built taking into account the principle of AGW (that human emissions of GHGs can change the Earth’s temperature and therefore its climate.) In the same way that this is not the Theory of Gravity, but uses the principles of the Theory of Gravity, models are not AGW, but use the principles of AGW to make predictions. ---
**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 17, 2009, 8:49pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/63 "2009-06-17T20:49:18Z")
**Wincerind** and **Sage Rat** make very good points. ---
**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 17, 2009, 9:17pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/64 "2009-06-17T21:17:00Z")
> [@wevets](#): > > I think part of the problem here is that I would disagree with your definition of AGW, **Blake**. I would define AGW theory as stating: **Human emissions of greenhouse gases have the potential to increase the Earth’s average temperature and change the general state of Earth’s climate.** Unfortunately, AGW proponents like Mann are going beyond saying that it’s possible that GHG emissions are causing GW; they’re saying that they are. ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [June 18, 2009, 12:10am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/65 "2009-06-18T00:10:26Z")
**Quartz** , did you read my post? Seems the statement that current warming is to a large degree due to human action is justified. ---
**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 18, 2009, 6:12am UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/66 "2009-06-18T06:12:49Z")
> [@wevets](#): > > **Quartz** , did you read my post? Seems the statement that current warming is to a large degree due to human action is justified. Of course I read it. The problem is the final link. We know that humans are emitting gasses that are GHGs. We know that the Earth has been warming. We know that the amount of CO2 in the atmosphere has increased - either from one vanishingly small amount to another, or by a large percentage, depending upon how you look at it. We don’t know that these GHG emissions are actually causing the warming we’ve seen. It certainly seems reasonable, but no one has yet demonstrated that human GHG emissions are causing the warming we’ve been experiencing. ---
**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 18, 2009, 12:58pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/67 "2009-06-18T12:58:29Z")
> [@Quartz](#): > > It certainly seems reasonable, but no one has yet demonstrated that human GHG emissions are causing the warming we’ve been experiencing. The [greenhouse effect](http://en.wikipedia.org/wiki/Greenhouse_effect), as I understand it has been fairly conclusively proven. Comparing the Earth to the Moon or Mars and other planets has allowed us to calculate that without an atmosphere and greenhouse layer, the Earth would be roughly -0.4F. We know that there is a greenhouse effect and what it’s overall contribution is. The question is what gases produce how much of the effect and how much effect modifying those values will cause. Now since we know the process by which the greenhouse effect works–heat is collected within the material and then radiated back out in all directions, rather than just back out into space–it’s principally a question of how much a particular gas at a particular concentration absorbs heat and what the limit of absorption is. That can be done in a laboratory. Since we can measure the concentration of gases in the atmosphere, we can use the above-collected data and math/computer simulation to determine what will happen by changing the concentrations of the gases. To **verify** that these values are correct, what we do is we take all of our measurements of the atmosphere over the course of the last X number of years (the longer the better) and make those changes in concentrations in our simulator and see if the output temperature is the same as that seen in the real world. Of course, since the output sun is non-constant, you need to add that in. Since the ocean is a big heat sink, you need to add that in, since …so on and so forth, your simulation needs to also include quite a bit of other stuff to match the real world output, but solving for those is pretty much the same process. You do your best lab testing to determine the physical properties, plug that into the simulator, and see if what you get matches the real world. Now we’ve got a good dozen simulators and their output is getting better as more things are added (like solar output and oceanic bodies and so forth), but this is all being tested against our recorded past. With something with that many variables, getting anything which basically resembles the real world output is actually quite impressive. If you can accomplish that, it’s really quite a bit of a proof. But at the same time, that means that it’s quite easily possible that some of your percentages are wrong and it all just happened to come to the right answer. BUT, that’s why there isn’t just one group doing lab tests, there isn’t just one group creating climate models, there isn’t just one group measuring real world states, etc. Where one group might get a couple figures transposed or measurements wrong, if all all 12 independent and competitive groups are coming up with very similar results and those results match back to real world data, I’d tend to buy that–noise in the data aside–we’ve got a legitimate test on our hands. ---
**Author:** ![Snickers](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@Snickers](https://boards.straightdope.com/u/Snickers)\ **Post date:** [June 18, 2009, 1:53pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/68 "2009-06-18T13:53:35Z")
What’s the goal here? I mean, this discussion is enlightening and interesting, but I can’t help asking what the purpose of it all is. Is anthropogenic global warming falsifiable - does it really matter? Regardless of whether human activity causes global warming, shouldn’t we be taking all steps to minimize our output of known greenhouse gases anyway, just in case? Or is the goal of finding AGW falsifiable merely in order to continue irresponsible practices without care for the cost? Don’t we have a duty to do our part to take as much care of our environment as we can, even though the Earth can shake us off like a bad cold when looked at in geologic terms? If we continue to dump billions and billions of tons of greenhouse gases into the atmosphere and it turns out that AGW is correct, what then? Too bad so sad? Sounds wildly irresponsible to me. Going back to the asteroid analogy posted earlier, shouldn’t we be doing all we can to minimize our chances of getting hit by the big one instead of just saying, “ah, screw it?” If we do all we can and it’s AGW isn’t true, we’ve lost nothing (and hopefully the world’s better for it.) If we do nothing and AGW is true…well. ---
**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 18, 2009, 2:38pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/69 "2009-06-18T14:38:08Z")
> [@Snickers](#): > > What’s the goal here? I mean, this discussion is enlightening and interesting, but I can’t help asking what the purpose of it all is. Is anthropogenic global warming falsifiable - does it really matter? Yes. > [@](#): > > Regardless of whether human activity causes global warming, shouldn’t we be taking all steps to minimize our output of known greenhouse gases anyway, just in case? IMHO yes, if you take away those last three words. > [@](#): > > Or is the goal of finding AGW falsifiable merely in order to continue irresponsible practices without care for the cost? We do not know if they are irresponsible. > [@](#): > > Don’t we have a duty to do our part to take as much care of our environment as we can Yes. How best to do it is a very difficult question. > [@](#): > > If we continue to dump billions and billions of tons of greenhouse gases into the atmosphere and it turns out that AGW is correct, what then? Too bad so sad? Sounds wildly irresponsible to me. We don’t know if GW is beneficial or not. It might just be staving off the next ice age. We don’t know what the long-term effects of sea level rises will be. Sure, certain areas will become submerged, but will other areas become fertile? How will it affect the weather? We simply don’t know. More research is needed. We know too little and determining the falsifiability of AGW will help considerably. ---
**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 18, 2009, 2:44pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/70 "2009-06-18T14:44:30Z")
> [@Sage\_Rat](#): > > Now we’ve got a good dozen simulators and their output is getting better as more things are added (like solar output and oceanic bodies and so forth), but this is all being tested against our recorded past. I am vastly skeptical of computer models. I don’t believe that any of them have been shown to be accurate. They require extensive tweaking to match past data. The Earth is not sufficiently understood. Plus there’s the issue of the researchers wanting to find something of interest. ---
**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 18, 2009, 2:52pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/71 "2009-06-18T14:52:17Z")
> [@Quartz](#): > > I am vastly skeptical of computer models. I don’t believe that any of them have been shown to be accurate. They require extensive tweaking to match past data. The Earth is not sufficiently understood. Plus there’s the issue of the researchers wanting to find something of interest. Which is the reason why there’s a certain probability of reliability given to the output and margins of error. And I’d question the veracity of your statement that everything has to be “massively tweaked” to reach something like earthly results. You can look at the PDF I linked to and you’ll see that while there is variation between various people’s attempts to recreate the conditions and separate them into parts, overall everything rises and falls quite nicely with one another. It should also be noted that there is no simulation made by anyone–simplistic or decently complex–which says that increasing the partcular gases which make up the greenhouse layer will do anything other than increase the average global temperature. While the preciseness of models might be an issue, short of proving that the whole concept of a “greenhouse effect” is false, there is going to be global warming on some scale or another. ---
**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 21, 2009, 6:38pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/72 "2009-06-21T18:38:29Z")
> [@Sage\_Rat](#): > > It should also be noted that there is no simulation made by anyone–simplistic or decently complex–which says that increasing the partcular gases which make up the greenhouse layer will do anything other than increase the average global temperature. Do you mean no simulation published? Unfortunately, this falls into the ‘Well, they would show warming, wouldn’t they?’ field and back to the OP’s issue of falsifiability. And given what happenned to Lomborg and others, who’s going to dare publish one anyway? Note that I think that that last is very sad. ---
**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 21, 2009, 7:42pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/73 "2009-06-21T19:42:08Z")
> [@Quartz](#): > > Do you mean no simulation published? I mean that no one yet has been able to create a climate model based on our physical understanding of chemistry and whatnot that produces any other result. to the best of our knowledge, exact numbers aside, more greenhouse gases means an increase in global temperature. “To the best of our knowledge” is certainly not a guarantee, but no honest climate scientist says otherwise. They say that for any one particular climate model that it’s got X% chance of being correct and Y% chance of being totally flaming wrong. But X is a larger number and has been steadily growing over the last 60 years, while as Y has been steadily shrinking. X isn’t 100% so you’re perfectly free to place a bet otherwise, but the smart money is on the people who have the understanding of the physical chemistry and whatnot. > [@](#): > > And given what happenned to Lomborg and others, who’s going to dare publish one anyway? Note that I think that that last is very sad. [Lomborg](http://en.wikipedia.org/wiki/Bjorn_Lomborg) was tried for and “convicted” of falsifying data and discarding negative results. What exactly is bad about that? ---
**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 21, 2009, 8:10pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/74 "2009-06-21T20:10:53Z")
> [@Sage\_Rat](#): > > [Lomborg](http://en.wikipedia.org/wiki/Bjorn_Lomborg) was tried for and “convicted” of falsifying data and discarding negative results. What exactly is bad about that? You mean apart from him being later vindicated? ---
**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 21, 2009, 8:31pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/75 "2009-06-21T20:31:07Z")
> [@Quartz](#): > > You mean apart from him being later vindicated? So…what’s the problem here exactly? He’s taken to court and the court decides against him. He appeals and the second court decides in his favor. I see that happen every day in cities all around the world. If this is a grave injustice to fight court battles, sometimes winning, sometimes losing, I’m not seeing it. What exactly is your recommendation over having peer reviews and trials? What great flaw in the justice system is so grievous that we must replace the whole thing? ---
**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 21, 2009, 9:43pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/76 "2009-06-21T21:43:54Z")
> [@Quartz](#): > > You mean apart from him being later vindicated? It was when I became aware of Lomborg that I began to doubt the effectiveness of many of the solutions put forward to deal with AGW. However, just like with Monckton, it seems to me that the skeptics are not paying careful attention on what their “champions” are doing and saying. **Lomborg does not deny that climate change by AGW is happening**. > **[FAQ](https://lomborg.com/faq)** > [@](#): > > Q: Does Lomborg deny man-made global warming exists? > > A: No. In Cool It he writes: “global warming is real and man-made. It will have a serious impact on humans and the environment toward the end of this century” (p8). ---
**Author:** ![wevets](https://avatars.discourse-cdn.com/v4/letter/w/e9a140/32.png) [@wevets](https://boards.straightdope.com/u/wevets)\ **Post date:** [June 29, 2009, 9:49pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/77 "2009-06-29T21:49:48Z")
> [@Quartz](#): > > Of course I read it. The problem is the final link. We know that humans are emitting gasses that are GHGs. We know that the Earth has been warming. We know that the amount of CO2 in the atmosphere has increased - either from one vanishingly small amount to another, or by a large percentage, depending upon how you look at it. We don’t know that these GHG emissions are actually causing the warming we’ve seen. It certainly seems reasonable, but no one has yet demonstrated that human GHG emissions are causing the warming we’ve been experiencing. I think a little basic chemistry will help you there. Given the massive numbers of molecules involved, if human-generated GHGs can absorb infrared in the ranges I mention in the earlier post, they will absorb in that range. It is magical thinking to believe that somehow the GHGs are there, they’re human-emitted, but they aren’t retaining heat the way laboratory measurements indicate that they are. ---
**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 29, 2009, 10:25pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/78 "2009-06-29T22:25:06Z")
> [@wevets](#): > > I think a little basic chemistry will help you there. Given the massive numbers of molecules involved, if human-generated GHGs can absorb infrared in the ranges I mention in the earlier post, they will absorb in that range. Theories are not enough. We need experimental evidence. Nobody has shown that human GHGs are actually significantly absorbing IR. And nobody has shown that if they are, the absorption is actually producing the warming we are seeing. If things were as simple as you suggest then falsifiability should be fairly simple. But it isn’t. Earth’s climate is monstrously complex, and a lot 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 29, 2009, 10:54pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/79 "2009-06-29T22:54:17Z")
> [@Quartz](#): > > Theories are not enough. We need experimental evidence. Nobody has shown that human GHGs are actually significantly absorbing IR. > **[Carbon dioxide in the atmosphere of Earth](https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmosphere)** > > In the atmosphere of Earth, carbon dioxide (CO2) is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis, and oceanic carbon cycle. It is one of three main greenhouse gases in the atmosphere of Earth. In 2024, the concentration of carbon dioxide in the atmosphere reached 427 ppm or 0.0427% (on a molar basis), representing a mass of 3341 gigatonnes. This is an increase of 50% since the start of the Industrial Revolution, up from 280 ppm during the 10,00... > [@](#): > > Despite its relatively small concentration overall in the atmosphere, CO2 is an important component of Earth’s atmosphere because it absorbs and emits infrared radiation at wavelengths of 4.26 µm (asymmetric stretching vibrational mode) and 14.99 µm (bending vibrational mode), thereby playing a role in the greenhouse effect.[4] > **[How do human CO2 emissions compare to natural CO2 emissions?](https://skepticalscience.com/human-co2-smaller-than-natural-emissions.htm)** > > \The CO2 that nature emits (from the ocean and vegetation) is balanced by natural absorptions (again by the ocean and vegetation). Therefore human emissions upset the natural balance, rising CO2 to levels not seen in at least 800,000 years. In... > [@](#): > > Carbon isotopes - the human “fingerprint” > > How can we know the rising CO2 levels are due to human activity? The carbon atom has several different isotopes (eg - different number of neutrons). Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons. Plants have a lower C13/C12 ratio than in the atmosphere. If rising atmospheric CO2 comes fossil fuels, the C13/C12 should be falling. Indeed this is what is occuring (Ghosh 2003) and the trend correlates with the trend in global emissions. > > The ocean’s diminishing ability to absorb CO2 > > While the ocean absorbs around half of human CO2 emissions, empirical observations reveal the oceans are losing their ability to absorb CO2. > > ``` > * Quéré 2007 found that the Southern Ocean has reached its saturation point, diminishing its ability to absorb more CO2. > * Schuster 2007 found that CO2 absorption by the North Atlantic has dropped even more dramatically, halving over the past decade. > * Park 2008 found a sudden, considerable reduction in the recent uptake of CO2 in the East/Japan Sea. > > ``` > > If this trend continues, it potentially leads to a positive feedback where the oceans take up less CO2 leading to CO2 rising faster in the atmosphere leading to increased global warming. > [@Quartz](#): > > And nobody has shown that if they are, the absorption is actually producing the warming we are seeing. > **[Does CO2 always correlate with temperature (and if not, why not?)](https://skepticalscience.com/co2-temperature-correlation.htm)** > > \Even during a period of long term warming, there are short periods of cooling due to climate variability. Short term cooling over the last few years is largely due to a strong La Nina phase in the Pacific Ocean and a prolonged solar minimum.\ > [@](#): > > The broader picture in this scenario is to recognise that CO2 is not the only factor that influences climate. There are a number of forcings which affect the net energy flux into our climate. Stratospheric aerosols (eg - from volcanic eruptions) reflect sunlight back into space, causing net cooling. When solar activity increases, the net energy flux increases. Figure 5 shows a composite of the various radiative forcings that affect climate. > > When all the forcings are combined in Figure 6, the net forcing shows good correlation to global temperature. There is still internal variability superimposed on the temperature record due to short term cycles like ENSO. The main discrepancy is a decade centered around 1940. This is thought to be due to a warming bias introduced by US ships measuring engine intake temperature. > > So we see that climate isn’t controlled by a single factor - there are a number of influences that can change the planet’s radiative balance. However, for the last 35 years, the dominant forcing has been CO2. > [@Quartz](#): > > If things were as simple as you suggest then falsifiability should be fairly simple. But it isn’t. Earth’s climate is monstrously complex, and a lot more research is required. I guess if you blink you will miss it (posted 2 times already): > **[RealClimate: What the IPCC models really say Lo que dicen realmente los...](https://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/)** > > RealClimate: Over the last couple of months there has been much blog-viating about what the models used in the IPCC 4th Assessment Report (AR4) do and do not predict about natural variability in the presence of a long-term greenhouse gas related... > [@](#): > > So, to give one possibility, if the global mean temperature from 2050 to 2070 would end up being lower than the 1950 to 1970 global mean temperature, would that be enough to falsify the IPCC projections, assuming no volcanic eruptions, cometary impacts, etc.? > > [Response: …and that the trajectories of the GHGs and aerosols looked something like this scenario. Yes. - gavin] And \*\*wevets \*\*already mention several others. ---
**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:** [June 29, 2009, 11:44pm UTC](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911/80 "2009-06-29T23:44:41Z")
[QUOTE=Shalmanese] 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? [/quote] :dubious: We can’t, and that’s precisely why we shouldn’t classify so-called just-so-stories as scientific hypotheses. [Previous page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=3) [Next page](https://boards.straightdope.com/t/is-anthropogenic-global-warming-falsifiable/499911.md?page=5)