tag:blogger.com,1999:blog-19727420.post43709967371381293..comments2024-03-23T12:05:13.464-07:00Comments on Ideas: Trudeau and Putin: Ideology vs InterestDavid Friedmanhttp://www.blogger.com/profile/06543763515095867595noreply@blogger.comBlogger58125tag:blogger.com,1999:blog-19727420.post-45796986554672568932015-12-29T09:13:49.926-08:002015-12-29T09:13:49.926-08:00"Interesting choice of words."
Directly..."Interesting choice of words."<br /><br />Directly measuring a forcing is decidedly nontrivial. Are you disputing the 3.7 W/m**2 figure for forcing for doubled CO2? Are you disputing that we have raised CO2 from roughly 280 ppm to roughly 400 ppm? If you don't dispute those, is there any particular reason you're making potshots?<br /><br />"Also interesting choice of words, given that the concept of CO2 saturation (or indeed any gas saturation) is pretty uncontroversial, but you've chosen to describe it as a far-end denial position."<br /><br />CO2 is saturated and <b>so can't have any effect</b>. Compound phrase. The last bit is very important.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-46747210853873301842015-12-24T06:05:55.239-08:002015-12-24T06:05:55.239-08:00@James Picone:
"the measured difference in fo...@James Picone:<br />"the measured difference in forcings between the bottom of the little ice age and today is less than forcing value we expect for the CO2 we've emitted over preindustrial."<br /><br />Interesting choice of words.<br /><br />"This is before feedbacks; before any of that; and it's a pretty uncontroversial value. If you think the greenhouse effect doesn't exist, or CO2 is saturated and so can't have any effect, or some similar far-end denial position"<br /><br />Also interesting choice of words, given that the concept of CO2 saturation (or indeed any gas saturation) is pretty uncontroversial, but you've chosen to describe it as a far-end denial position.<br /><br /><br />-excelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-59189276114097549032015-12-24T04:24:27.505-08:002015-12-24T04:24:27.505-08:00@First anon:
I'm saying that things that are n...@First anon:<br />I'm saying that things that are not cat 5/6/7 in their abstract are vanishingly unlikely to reject anthro >50%. This is different from saying cat 5/6/7 doesn't exist. If an abstract took the position that anthro <50%, either implicitly or explicitly.<br /><br />If people think their paper is support for Weird Thing, they put that in their abstract. Papers on galactic rotation curves will say when they don't mesh with relativity, for example. It's an interesting result.<br /><br />@Second anon:<br />Let me put it this way: the measured difference in forcings between the bottom of the little ice age and today is less than forcing value we expect for the CO2 we've emitted over preindustrial. I linked to proxy TSI data, there's a .75 W/m**2 difference between the lowest value on the graph and the highest value. We've increased CO2 from preindustrial 280 ppm to ~400 ppm. Forcing due to CO2 is 5.35 * ln(C/C0) W/m**2, or ~1.9 W/m**2 for CO2 emitted to date. This is before feedbacks; before any of that; and it's a pretty uncontroversial value. If you think the greenhouse effect doesn't exist, or CO2 is saturated and so can't have any effect, or some similar far-end denial position, now would be a good time to actually bring it up instead of snarking.<br /><br />Notice that 1.9 W/m**2 is ~2.5 times as large as 0.75 W/m**2.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-25249582279629550822015-12-23T07:16:48.011-08:002015-12-23T07:16:48.011-08:00@James Picone:
"More accurate: What made that...@James Picone:<br />"More accurate: What made that bounce /start/ ? "<br /><br />No, I think the "What made the bounce stop" question is of bigger interest, and even "did the bounce stop".<br /><br />"Plenty of content."<br /><br />No.<br /><br />"Looking at that and going "Well maybe it's internal variability. Over several decade timescales" falls afoul of conservation of energy."<br /><br />Another interesting claim, but with little to support it.<br /><br />"Sure it does."<br /><br />No, it doesn't.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-8612179545756624532015-12-22T23:12:31.129-08:002015-12-22T23:12:31.129-08:00@James Picone
You argue that any paper in categor...@James Picone<br /><br />You argue that any paper in categories 2 and 3 must have been implicitly in category 1 because to not be would be untenable. But how tenable are categories 5/6/7, which also involve rejecting the claim that warming is primarily human caused? You consider the positions that these categories refer to to be untenable too - right?<br /><br />If so, why bother doing this aggregation work at all - why not just declare that 100% of climate scientists hold the position "global warming is real and humans are the principal cause", as this can be determined by a simple assessment of what is and isn't tenable?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-60506843451880701932015-12-22T20:55:49.239-08:002015-12-22T20:55:49.239-08:00"That's an interesting claim. What made t..."That's an interesting claim. What made that "bounce" stuff stop?"<br /><br />More accurate: What made that bounce /start/?<br /><br />Global average surface temperature is not a bouncing ball. It reacts to forcings. It got cold because of a negative forcing (likely reduced TSI). It got warm again when that negative forcing went away/went positive (TSI caught up).<br /><br />There is, to the best of my knowledge, no evidence of TSI or other forcing changes on the same order of magnitude as the ~1.9W/m**2 of CO2 forcing over the surface temperature record.<br /><br /><a href="ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/delaygue2010be10.txt" rel="nofollow">Here</a> is some proxy data for TSI over the last several centuries. SkS has a <a href="http://www.skepticalscience.com/pics/Delaygue_TSI.gif" rel="nofollow">graph</a> of that data. It's clear that there's a trend since the LIA, and that's almost certainly one of the factors that caused it.<br /><br />There's no trend in TSI since instrumental records began, and if there is a trend it's negative. I linked you to the satellite data for it above. Additionally, the gap between the lowest value on that TSI graph and the highest value is less than the CO2 forcing since preindustrial! And that's before albedo!<br /><br />"Pithy, but contentless."<br /><br />Plenty of content. Total heat content of the entire system is measurably increasing. Looking at that and going "Well maybe it's internal variability. Over several decade timescales" falls afoul of conservation of energy. It's the same reason we know climate isn't a random walk - because physics doesn't work that way.<br /><br />"Doesn't really seem to address the problem."<br /><br />Sure it does. Do you know of any forcing of equivalent size?James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-41929791713508627552015-12-21T18:11:52.439-08:002015-12-21T18:11:52.439-08:00"LIA bounce stuff is very much done before in..."LIA bounce stuff is very much done before instrumental records. Not a factor for present warming. And it's TSI, which certainly isn't in a warming direction since records began."<br /><br />That's an interesting claim. What made that "bounce" stuff stop?<br /><br />"Note that I don't claim there's a significant negative trend, only that if there is a trend it is negative."<br /><br />K.<br /><br />"Over here we call it "The second law of thermodynamics"<br /><br />Pithy, but contentless.<br /><br />"This IPCC AR4 chapter contains observationally-based ECS estimates if you want the complex version. Remember we've got 1.9 W/m**2 of CO2 forcing (alone) over preindustrial, assuming 280 ppm for preind. That heat has to go somewhere."<br /><br />Doesn't really seem to address the problem.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-89647550412294666112015-12-21T11:54:34.455-08:002015-12-21T11:54:34.455-08:00"Going by the temperature records the evidenc..."Going by the temperature records the evidence seems to be for a positive trend, pre-industrialism. Which negative trends are we talking about?"<br /><br /><a href="http://woodfortrees.org/plot/pmod" rel="nofollow">TSI</a>.<br /><br />LIA bounce stuff is very much done before instrumental records. Not a factor for present warming. And it's TSI, which certainly isn't in a warming direction since records began.<br /><br />Note that I don't claim there's a significant negative trend, only that if there is a trend it is negative.<br /><br />"This is an assumption. A rather large one."<br /><br />Over here we call it "The second law of thermodynamics"<br /><br />"The calculation may or may not be simple, but it seems to rely on large assumptions and some claims that contradict the historical record."<br /><br /><a href="https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-6-2.html" rel="nofollow">This</a> IPCC AR4 chapter contains observationally-based ECS estimates if you want the complex version. Remember we've got 1.9 W/m**2 of CO2 forcing (alone) over preindustrial, assuming 280 ppm for preind. That heat has to go somewhere.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-76028138183162146072015-12-20T05:55:54.492-08:002015-12-20T05:55:54.492-08:00@James Picone
"When I say it's "ass...@James Picone<br /><br />"When I say it's "assuming that they can do maths", I don't exactly mean "2+2 = 4 => climate change", I mean that given certain common knowledge that can be attributed to people writing climate change papers, the ability to add up forcings makes it immediately obvious that it's gotta be almost 100% anthropogenic. There's no trend at best for any of the known natural forcings (TSI, vulcanism being the big ones), and there's some evidence for negative trend (that is, the natural forcings should be making things cooler)."<br /><br />Going by the temperature records the evidence seems to be for a positive trend, pre-industrialism. Which negative trends are we talking about?<br /><br />"Total heat content of the entire system is increasing, which makes it immediately obvious that it can't be natural variation - not over that timescale, not that large an effect."<br /><br />This is an assumption. A rather large one.<br /><br />"The only significant changes in forcing over that period are both anthropogenic - aerosols and greenhouse gases. This is not a difficult calculation."<br /><br />The calculation may or may not be simple, but it seems to rely on large assumptions and some claims that contradict the historical record.<br /><br /><br />-excelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-29935430821291579852015-12-20T00:57:15.323-08:002015-12-20T00:57:15.323-08:00@Anonymous:
To quote myself from earlier:
"Wh...@Anonymous:<br />To quote myself from earlier:<br />"When I say it's "assuming that they can do maths", I don't exactly mean "2+2 = 4 => climate change", I mean that given certain common knowledge that can be attributed to people writing climate change papers, the ability to add up forcings makes it immediately obvious that it's gotta be almost 100% anthropogenic. There's no trend at best for any of the known natural forcings (TSI, vulcanism being the big ones), and there's some evidence for negative trend (that is, the natural forcings should be making things cooler). Total heat content of the entire system is increasing, which makes it immediately obvious that it can't be natural variation - not over that timescale, not that large an effect. The only significant changes in forcing over that period are both anthropogenic - aerosols and greenhouse gases. This is not a difficult calculation."<br /><br />Alternately, <a href="http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-7.html" rel="nofollow">AR4 chapter 9</a> lists some pretty good reasons.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-42225051334697249232015-12-17T04:59:00.178-08:002015-12-17T04:59:00.178-08:00"The position "humans cause global warmi..."The position "humans cause global warming, but it's <50%" is not tenable. Therefore, papers in cat 2/3, with high probability, do not take that position."<br /><br />Why is it "not tenable"?<br /><br /><br />-excelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-38935947693696755682015-12-16T02:55:03.514-08:002015-12-16T02:55:03.514-08:00@Anonymous:
The position "humans cause global...@Anonymous:<br />The position "humans cause global warming, but it's <50%" is not tenable. Therefore, papers in cat 2/3, with high probability, do not take that position.<br /><br />Papers in cat 5/6/7 either implicitly or explicitly don't allow for that inference - perhaps because they argue that in addition to human warming there has been significant natural variability (i.e., cat 5).<br /><br />The 'middle position' of "warming happened, anthro, but I refuse to estimate how much" is similarly silly because of how untenable the <50% position is.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-85750591553392483522015-12-14T06:58:02.655-08:002015-12-14T06:58:02.655-08:00"The argument is "You can legitimately i..."The argument is "You can legitimately infer 'main cause of warming' from the statements in cat 2/3, because other positions are not tenable"."<br /><br />This seems to be completely at odds with the paper itself, based on these descriptions from the paper:<br />Cat 1: Explicitly states that humans are the primary cause of recent global warming<br />Cat 2: Explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a known fact<br />Cat 3: Implies humans are causing global warming. E.g., research assumes greenhouse gas missions cause warming without explicitly stating humans are the cause<br /><br />as well as these descriptions from the data file used in the paper:<br /><br />Cat 1: 1,Explicitly endorses and quantifies AGW as 50+% <br />Cat 2: 2,Explicitly endorses but does not quantify or minimise<br />Cat 3: 3,Implicitly endorses AGW without minimising it <br /><br />I don't see how inferring "humans main cause for all 3 categories" can be legitimized based on these very specific categorizations of endorsement.<br /><br /><br />-excelAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-62437668700666830572015-12-13T03:38:57.304-08:002015-12-13T03:38:57.304-08:00The argument is not "Cook is correct; therefo...The argument is not "Cook is correct; therefore the statement was fine". The argument is "You can legitimately infer 'main cause of warming' from the statements in cat 2/3, because other positions are not tenable". That is, the argument is that Cook did find 97% consensus on main-cause-of-warming, and that that is an inference from 97% being in categories 1-3.<br /><br />Again, I think the Real Story of Cook13 was how few papers are in categories 5-7, and I think that if Cook was trying to do something devious and underhanded, raising the money to make the paper open access, setting up a website where you can rate papers yourself, publishing the raw data, doing a secondary survey of scientists, and publishing that raw data, is a very strange way to go about it. These are not the actions of someone trying to be deliberately deceptive. They are the actions of somebody who thinks they're correct and is trying to be open about what they're doing.<br /><br />Could you refresh your memory on exactly which paper you're referring to re: natural cycles? Nuccitelli et al. 2012 is perhaps of interest here: <a href="http://www.sciencedirect.com/science/article/pii/S0375960112010389" rel="nofollow">link</a>, which included <a href="http://www.skepticalscience.com/graphics.php?g=65" rel="nofollow">this</a> figure, based on Church 2011 and Levitus 2012.<br /><br />That graph makes the claim that >50% of increase in surface temperature heat content is due to land/ocean heat exchange look a little ridiculous. That's the kind of data that I'm talking about when I conclude that anthro contributions to recent heating are almost certainly 100%ish.<br /><br />The idea that heat exchange with oceanic depths lower than those included in that figure resolve the problem is similarly ridiculous. Heat exchange from that depth to the actual abyss is not even of the same order of magnitude; and I'd be surprised if you didn't realise that.<br /><br />(Plus, arguably 'global warming' means the increase in total heat content of the system, not specifically surface temperature.)<br /><br />IPCC projections differ on forcing evolution, not on the kinds of facts about the climate system I'm talking about. If you're referring to all of the CMIP bundle of models, I think you're being fooled by weather.<br /><br />I would argue that the models are pretty accurate. They're certainly better than the naive projection would have been. In my experience most of the demonstrations that they're not doing okay only work because of deliberately poor baseline selection; try comparing trends, which makes that less of a problem. I've linked to SkS' article comparing FAR/SAR/TAR/AR4 projections to reality to you before.<br /><br />I haven't read that essay of Orwell's. Got it open in a tab now.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-14459328569932600082015-12-13T00:18:02.639-08:002015-12-13T00:18:02.639-08:00On the question of the effect of climate change on...On the question of the effect of climate change on plant growth, an article published in the Proceedings of the National Academy:<br /><br />"Using a unique dataset of tree biomass collected over the past 22 years from 55 temperate forest plots with known land-use histories and stand ages ranging from 5 to 250 years, we found that recent biomass accumulation greatly exceeded the expected growth caused by natural recovery."<br /><br />http://www.pnas.org/content/107/8/3611.abstractDavid Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-46314496884577732962015-12-11T23:52:51.749-08:002015-12-11T23:52:51.749-08:00At only a slight tangent, have you read Orwell'...At only a slight tangent, have you read Orwell's "Politics and the English Language?" I think it's relevant.<br /><br />http://www.orwell.ru/library/essays/politics/english/e_polit/David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-56393965231992822022015-12-11T23:40:23.246-08:002015-12-11T23:40:23.246-08:00"Do you concede that if the evidence is as st..."Do you concede that if the evidence is as strong as I think it is, then Cook's inference is defensible?"<br /><br />No. What Cook wrote was:<br /><br />"Cook et al. (2013) found that over 97% endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause."<br /><br />Suppose he had written "Cook et al. (2013) found that 2+2=4."<br /><br />That would have been a lie. It's true that 2+2=4, but Cook et. al. (2013) didn't find it.<br /><br />If he had written "found that 97% of the abstracts endorsed the view that 2+2=4" he would also have been lying.<br /><br />Similarly here. I'm not interested in arguing about how many climate scientists believe what. I'm arguing about whether Cook lied about the contents of an article of which he was the lead author. That's the fact you keep trying to evade. <br /><br />His statement isn't a statement about how many people believe what. It's a statement about what the paper found in the abstracts examined. What the paper found in the abstracts examined was that 1.6% (of the abstracts expressing an opinion on the causation of warming) endorsed the view that Earth is warming and human emissions of greenhouse gases are the main cause. Representing that as 97% is a lie.<br /><br />Do you disagree? Do you want to claim that an abstract saying that greenhouse gases contribute to warming is saying they are the main cause? The question isn't what the author believed, it's what the abstract said.<br /><br />I do not consider it possible that reasonable people cannot distinguish between "X is true" and "my paper found that 97% of abstracts endorsed X." I do, unfortunately, consider it possible that many people put tribal loyalty above truth, whether by lying to other people or to themselves. It's a pattern I have observed over and over again on both sides of the climate argument online.<br /><br />So far as your argument that it has to be almost 100%, it's wrong. I posted a link a while back to a published journal article offering evidence that global temperature reflects the sum of AGW plus a cyclic pattern, attributed to exchanges of heat between atmosphere and ocean, with a period of about seventy years. If that's right, then for the rising part of the cycle warming is due in roughly equal amounts to AGW and the cycle.<br /><br />Climate is a complicated system. If the IPCC had an adequate model it would produce a single projection instead of lots of them, and the projection would be reasonably accurate. I think it quite likely that the main cause of warming is AGW, but it isn't certain.<br /><br />Total heat content of the system may be increasing, but what we are measuring is not the heat content of the system. We have halfway decent data on ocean heat content only for the end of the period, and even that doesn't go all the way down. The heat capacity of the ocean is very large, and we can't say on theoretical grounds how the division of total heat between ocean and atmosphere+surface varies over time.<br /><br />But all of this is irrelevant to the central point, which is that Cook's claim was about what the abstracts examined said, and only 1.6% of them said something equivalent to main cause. You know that, whether or not you are willing to admit it.<br /><br />And you never have responded to the question of why, if it was an innocent error, the original paper lumped the 1.6% category in with two categories representing weaker claims, and only reported the 97% sum. I do not believe that you are sufficiently naive not to recognize the implications of that choice. David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-88767581243884667162015-12-10T02:25:32.456-08:002015-12-10T02:25:32.456-08:00@Zephyr:
I was referring to how long a 'spike&...@Zephyr:<br />I was referring to how long a 'spike' in methane concentrations would persist in the atmosphere vs a 'spike' in CO2 concentrations, not the atmospheric residence time of a single molecule. That is, if we release X methane at time t, at what time does methane concentration return to its previous value?<br /><br />I don't mean ~30 years to be anything like a hard number. <a href="http://www.realclimate.org/index.php/archives/2012/01/much-ado-about-methane/" rel="nofollow">This</a> realclimate post has some schematic diagrams of modelling of methane release that kinda show what I'm getting at - methane breaks down quite fast, in a geological sense, and CO2 does not, so the lifetime of a pulse of methane is governed more by how long it takes it to react away (partially into CO2), and the lifetime of a pulse of CO2 depends on how long it takes for other sinks in the carbon cycle to equilibrate.James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-49946244738303841872015-12-10T02:14:44.269-08:002015-12-10T02:14:44.269-08:00More Cook:
I think the fundamental disagreement he...More Cook:<br />I think the fundamental disagreement here might actually be on how strong the evidence for ~100% of the warming since preindustrial being anthropogenic is. Do you concede that if the evidence is as strong as I think it is, then Cook's inference is defensible?<br /><br />When I say it's "assuming that they can do maths", I don't exactly mean "2+2 = 4 => climate change", I mean that given certain common knowledge that can be attributed to people writing climate change papers, the ability to add up forcings makes it immediately obvious that it's gotta be almost 100% anthropogenic. There's no trend at best for any of the known natural forcings (TSI, vulcanism being the big ones), and there's some evidence for negative trend (that is, the natural forcings should be making things cooler). Total heat content of the entire system is increasing, which makes it immediately obvious that it can't be natural variation - not over that timescale, not that large an effect. The only significant changes in forcing over that period are both anthropogenic - aerosols and greenhouse gases. This is not a difficult calculation.<br /><br />Have you considered the possibility that the reason you don't see people-who-think-climate-change-is-a-problem agreeing with you about Cook is because of some fundamental difference in thought about the evidence, like the argument I'm outlining above, rather than an entire group of people, including rather a lot of scientists, being fundamentally dishonest?James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-89870981888969273172015-12-10T02:05:50.385-08:002015-12-10T02:05:50.385-08:00On negative effects:
The point is that there are v...On negative effects:<br />The point is that there are very obvious, very significant negatives, even for cold countries. Large anomalies tend to lead to deaths, even with low absolute temperatures. Any comparative advantage for Russia or Canada is going to be nontrivial to calculate, because while less deaths in winter is great and all, the larger warming effect at the poles is going to lead to very intense heatwaves compared to the ones we get in warm countries (on anomaly basis). Which of those wins out depends on things like how many more wildfires they're going to see, for example.<br /><br />On the link:<br />I'm using Pale Moon, which is a Firefox fork.<br /><br />On Cook:<br />I'm still kind of baffled that you take Cook making a mistake about which argument you made as evidence of mendacity. The blog post he was posting on made the argument he attributes to you, just after quoting your blog post. This is not a difficult slip of the brain to understand. And he's seen that argument so, so many times. Say you have no idea who Scott Alexander is, and you run into a blog post that links to Scott's anti-libertarian FAQ, quotes a little bit of it, and then says "Plus, who would pay for the roads?". Do you seriously think that there's no chance you might accidentally misidentify who-would-pay-for-the-roads to Scott?James Piconehttps://www.blogger.com/profile/00832432838264410137noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-43796397081025314042015-12-09T17:20:21.464-08:002015-12-09T17:20:21.464-08:00James Picone: "There are non-CO2 greenhouse g...James Picone: <i>"There are non-CO2 greenhouse gases that are increasing - methane, CFCs, a couple of others - but none of them have the raw forcing or the lifetime of CO2 (methane in the atmosphere decays over ~30 years, for example)."</i><br /><br />[Part 2/2]<br />As for the average residence time of methane:<br /><br /><i>«Methane (CH4) is a very effective greenhouse gas. While its atmospheric concentration is much less than that of carbon dioxide, methane is 20 times more effective at trapping infrared radiation! The atmospheric residence time of methane is approximately 8 years. Residence time is the average time it takes for a molecule to be removed, so in this case for every molecule of methane that goes into the atmosphere it stays there for 8 years until it is removed by some process.»</i><br /><a rel="nofollow">http://www.soest.hawaii.edu/mguidry/Unnamed_Site_2/Chapter%202/Chapter2C2.html</a><br /><br />This time seems to be accurate. This is the calculation using the data from the same previous source:<br /><br />(page 474)<br /><i>«Figure 6.2 | Schematic of the global cycle of CH4.»</i><br /><a rel="nofollow">http://climatechange2013.org/images/report/WG1AR5_Chapter06_FINAL.pdf</a><br /><br />Atmosphere [stock]: (1984 + 2970) ± 45 Tg CH4 = 4954 ± 45 Tg CH4<br /><br />Wetlands [source]: 177—288 Tg CH4/yr<br />Fossil fuels [source]: 85—105 Tg CH4/yr<br />Livestock [source]: 87—94 Tg CH4/yr<br />Landfills and waste [source]: 67—90 Tg CH4/yr<br />Geological sources [source]: 33—75 Tg CH4/yr<br />Rice cultivation [source]: 33—40 Tg CH4/yr<br />Biomass burning [source]: 32—39 Tg CH4/yr<br />Freshwaters [source]: 8—73 Tg CH4/yr<br />Termites [source]: 2—22 Tg CH4/yr<br />Hydrates [source]: 2—9 Tg CH4/yr<br /><br />Tropospheric OH [sink]: 454—617 Tg CH4/yr<br />Stratospheric OH [sink]: 16—84 Tg CH4/yr<br />Tropospheric CL [sink]: 13—37 Tg CH4/yr<br />Oxidations in soils [sink]: 9—47 Tg CH4/yr<br /><br />Total CO2 inflow [sources]:<br />Lower limit: (177+85+87+67+33+33+32+8+2+2) Tg CH4/yr = 526 Tg CH4/yr<br />Upper limit: (288+105+94+90+75+40+39+73+22+9) Tg CH4/yr = 835 Tg CH4/yr<br /><br />Total CO2 outflow [sinks]:<br />Lower limit: (454+16+13+9) Tg CH4/yr = 492 Tg CH4/yr<br />Upper limit: (617+84+37+47) Tg CH4/yr = 785 Tg CH4/yr<br /><br />Average residence time CH4 [lower limit]: (4954 - 45) Tg CH4 / 785 Tg CH4/yr ≈ <b>6.25 yr</b><br />Average residence time CH4 [upper limit]: (4954 + 45) Tg CH4 / 492 Tg CH4/yr ≈ <b>10.16 yr</b><br /><br />Thus, the average residence time of methane in the atmosphere is about twice as long as that of carbon dioxide.Zephyrhttps://www.blogger.com/profile/06978513789035443789noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-90168909799195080012015-12-09T17:17:28.006-08:002015-12-09T17:17:28.006-08:00James Picone: "There are non-CO2 greenhouse g...James Picone: <i>"There are non-CO2 greenhouse gases that are increasing - methane, CFCs, a couple of others - but none of them have the raw forcing or the lifetime of CO2 (methane in the atmosphere decays over ~30 years, for example)."</i><br /><br />[Part 1/2]<br />The above statement is inaccurate and misleading. First of all, there’s no such thing called lifetime of CO2 or of any other gas, but of its particles. You probably meant the “half life” or the average residence time (or average “lifetime”). Atmospheric methane “decays”, but not in 30 years, it starts “decaying” as soon as it’s emitted into the atmosphere. Likewise, CO2 also “decays” (e.g., it’s turned into organic matter by photosynthetic organisms), with the difference that the residence time of CO2 is much shorter than that of methane:<br /><br /><i>«Individual carbon dioxide molecules have a short life time of around 5 years in the atmosphere.»</i> [It should read <i>“average life time”</i>]<br /><a rel="nofollow">http//www.skepticalscience.com/co2-residence-time.htm</a><br /><br />The average residence time is actually closer to 4 years. You may prefer to make the calculation yourself:<br /><br />(page 471)<br /><i>«Figure 6.1 | Simplified schematic of the global carbon cycle.</i><br /><a rel="nofollow">http://climatechange2013.org/images/report/WG1AR5_Chapter06_FINAL.pdf</a><br /><br />Atmosphere [stock]: (589 + 240) Pg C * 3.67 Pg CO2/Pg C = 3042.43 Pg CO2<br /><br />Total respiration and fire [source]: (107.2 + 11.6) Pg C/yr * 3.67 Pg CO2/Pg C = 435.996 Pg CO2/yr<br />Ocean-atmosphere flux [source]: (60.7 + 17.7) Pg C/yr * 3.67 Pg CO2/Pg C = 287.728 Pg CO2/yr<br />Fossil fuels (coal, oil, gas) cement production [source]: 7.8 Pg C/yr * 3.67 Pg CO2/Pg C = 28.626 Pg CO2/yr<br />Net land use change [source]: 1.1 Pg C/yr * 3.67 Pg CO2/Pg C = 4.037 Pg CO2/yr<br />Freshwater outglassing [source]:1.0 Pg C/yr * 3.67 Pg CO2/Pg C = 3.67 Pg CO2/yr<br />Volcanism [source]: 0.1 Pg C/yr * 3.67 Pg CO2/Pg C = 0.367 Pg CO2/yr<br /><br />Gross photosynthesis [sink]: (108.9 + 14.1) Pg C/yr * 3.67 Pg CO2/Pg C = 451.41 Pg CO2/yr<br />Atmosphere-ocean flux [sink]: (60 + 20) Pg C/yr * 3.67 Pg CO2/Pg C = 293.6 Pg CO2/yr<br />Rock weathering [sink]: 0.3 Pg C/yr * 3.67 Pg CO2/Pg C = 1.101 Pg CO2/yr<br /><br />Total CO2 inflow [sources]:<br />(435.996+287.728+28.626+4.037+3.67+0.367) Pg CO2/yr = 760.424 Pg CO2/yr<br /><br />Total CO2 outflow [sinks]:<br />(451.41+293.6+1.101) Pg CO2/yr = 746.111 Pg CO2/yr<br /><br />Average residence time CO2: 3042.43 Pg CO2 / 746.111 Pg CO2/yr ≈ <b>4.08 yr</b>Zephyrhttps://www.blogger.com/profile/06978513789035443789noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-10993921909935097462015-12-06T10:57:55.944-08:002015-12-06T10:57:55.944-08:00"Broadly, yes. More specifically, you had ..."Broadly, yes. More specifically, you had 'category slippage', in which your not-intended-to-be-super-formal language could, if read unwarily, identify a different category to the ones that the paper, interpreted strictly, was about.<br /><br />Again, your claim that I objected to was not about articles vs abstracts but about beliefs of authors vs abstracts. You keep ignoring that. Where have I ever said or implied that only 1.6% of the authors believed that humans were the main cause? If I didn't say that, your claim about me was false. Why are you unwilling to admit that? You keep trying to change the subject.<br /><br />"This is what you're saying Cook is doing, when he shifts from categories 2/3 to "main cause of warming"."<br /><br />No. Category 1 was about the main cause of warming. Categories 2 and 3 were not. It isn't a slippage of language to claim that a paper holding that greenhouse gases contribute to warming asserts that humans are the main cause of warming. It's a falsehood. And, given the way Cook 2013 was written, pretty clearly a deliberate one. I don't think you ever offered an explanation of why only the summed figure for categories 1-3 was given and not the individual ones--when the individual figures would have shown that the strongest category represented a tiny fraction of the total. That being the category he was going, in another paper, to claim represented all of it.<br /><br />If you were stupid I would find your defenses of Cook more plausible, but you are obviously bright, and pooling 1.6% with two larger numbers to give 97%, then reporting the 97% and not the 1.6%, is a standard example of how to mislead with statistics. The second paper didn't say "97% of papers held that humans cause warming," which would be roughly the fuzzy language used in Cook et. al. 2013. It was quite explicit about "main cause" and what that meant. <br /><br />"the link between "CO2 is an anthropogenic forcing" and "warming is 50% human" is much tighter than that. It's really, genuinely *this close* to just assuming that the people who responded can do maths."<br /><br />Nonsense. There was a period of about thirty years in midcentury when global temperatures were constant to falling, despite increasing CO2. That makes it obvious that there are other causes of comparable strength, so the question of how much warming when was anthropogenic is an empirical question, not doing math. Papers that said humans were the main cause of warming were in category 1, and we know how many there were. Papers that did not say humans were the main cause of warming did not say humans were the main cause of warming, and claiming they did say that is a lie. How many authors believed it we don't know, at least from Cook et. al. 2013. But we do know how many abstracts said it, at least according to the authors of that paper.<br /><br />I remain disturbed by either your ability to persuade yourself that 2+2=5—more precisely that 1.6%=97%—when doing so is necessary to avoid admitting that a prominent figure on your side of the argument is dishonest, or your unwillingness to admit the fact in print. I can't tell which it is.<br />David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-74578707029670834362015-12-06T10:56:19.454-08:002015-12-06T10:56:19.454-08:00"Do you now acknowledge that it's entirel..."Do you now acknowledge that it's entirely plausible that Cook might have made a good-faith mistake about the contents of your argument, now that you've witnessed yourself making a similar mistake first-hand?"<br /><br />No. My mistake was not finding something. His "mistake" was asserting that I had made an argument I had not made and entirely ignoring the argument I had made. Since, after more than a year of discussing my argument with people who support him, I have not yet found any plausible defense of his claim in the second paper, the obvious explanation is that he knows he lied, having done so deliberately, and is counting on some people reading his response who did not read what he is responding to. <br /><br />It's possible that he simply assumed I had made the same argument as some other critic, but replying to my argument without reading it is irresponsible, and replying by accusing me of dishonesty is more than irresponsible. Indeed, it is the sort of behavior one would expect of someone who is interested in the effect of what he says, not whether it is true.<br /><br />My accusation of you was made to you, repeatedly, with the opportunity for you to rebut it, as you partially did—you did have a response that I missed, although that response failed to support your claim. He made no similar attempt, did not respond with a comment on my blog as he easily could have. David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-32658435128721711902015-12-06T10:54:20.063-08:002015-12-06T10:54:20.063-08:00With regard to the link, what browser are you usin...With regard to the link, what browser are you using? I'm using Firefox.David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.com