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Comments 251 to 275 out of 425:

251. anon1234 at 05:56 AM on 14 September, 2012
     For the record, irrational appeal to authority is a common logical fallacy, which is hardly inflammatory (he could easily defend himself and prove me wrong. Why is it ok for Sphaerica to accuse me of logical fallacies without being "snipped" but not vice versa? If this is an inappropriate place for such questions to be issued, I apologize in advance. Also, great site! I really enjoy the comments sections.
252. KR at 06:30 AM on 14 September, 2012
     AHuntington1 - I believe the issue is that you have made numerous assertions without backing evidence, such as "...increasing the ratio of Co2 to 02 significantly increases the distribution of 02 throughout the body..." and "More atmospheric C02 is beneficial for plants (as has been described in this thread) and animals." I haven't seen the latter in this thread, and in fact if you look at the relevant CO2 is plant food thread you will see that this is actually not the case - heightened CO2 has mixed, and in general negative, effects on plants due to effects such as changes in the hydrological cycle. You have then moved the goalposts - raising separate points (lactate mechanisms, antioxidants, hypoxia) - using references showing that insufficient CO2 is harmful, but not producing any evidence that excess CO2 is helpful. The term "Gish Gallop" applies to the rhetorical tactic of raising many unrelated points without fully addressing (or completing a reply to critiques) any of them, and it does seem to apply to your posts so far. If you are going to make claims, you need to support them. You have not.
253. anon1234 at 07:02 AM on 14 September, 2012
     KR, the first statement is backed up by the Bohr effect, and the fact that Co2 helps prevent acute hypoxia (potentially deadly lack of oxygen supply). These two facts show how Co2 (and especially a higher ratio of Co2 and O2) does indeed increase oxygen distribution throughout the body significantly. Co2 also displays antioxidant activity. I don't see the comments in the plant food thread that you are referring to. Do you deny that one major positive factor in plant growth (among others, such as soil type, and water quantity) is the quantity of Co2 in the area? Do you disagree with the litany of studies that show crop yield increases when Co2 increase was the only changing variable?
254. Stephen Baines at 08:09 AM on 14 September, 2012
     AHuntingdon I don't think you understand how the Bohr effect works. It's the difference in affinity of haemoglobin for O2 in the lung (low CO2) and in O2-starved (high CO2) tissues that increases efficiency of O2 supply to O2-starved tissues. If you increase CO2 in the lungs, you decrease the ability of haemoglobin in the lungs to take up O2 due to the very same chemistry. That will not increase O2 supply to internal tissues. You may also reduce the differential in O2 affinity between the lungs and O2-starved tissues, which will reduce effiency of supply of that O2 to O2-starved tissues. And no, CO2 is not considered a "major" factor affecting plant growth. Nutrients and water are far more important in nature. Only when the latter are in sufficient quantities (as in a greenhouse) do you see a substantial CO2 effect. That effect decreases as CO2 concentrations increase -- i.e., there is a law of diminishing returns. It is far less obvious for C4 than for C3 plants. You should read the CO2 is plant food thread in detail before commenting here. BTW...You should be aware the IPCC accounted for the fertilization by CO2 when assessing the effects of increasing CO2 on crops. They predicted an initial increase in production followed by substantial decreases after further increases due to effects on climate.
255. Philippe Chantreau at 08:21 AM on 14 September, 2012
     AHuntington1, how does high altitude increase the CO2 to O2 ratio? As pressure decreases, the mass of any given atmospheric element per unit of volume decreases and that applies to all of them: oxygen, nitrogen, carbon dioxide, all other well mixed gases. CO2 concentration within the range of altitudes at which humans can live does not vary in any significant way.
256. anon1234 at 11:16 AM on 14 September, 2012
     Stephen Baines, a higher affinity for O2 in the hemoglobin results in less oxygen transfer out of the blood, to tissues. More Co2 means less O2 is absorbed immediately into the hemoglobin, but the O2 that is picked up is easily distributed. Philippe Chantreau, that is a good point, and I did mis-type. People at high altitudes breathe less O2 (and Co2), but continue to metabolize glucose, which produces water and Co2. Thus, people at high altitudes are exposed to a higher ratio of Co2 to O2 internally. But yes, the atmosphere is less dense all around.
257. anon1234 at 11:24 AM on 14 September, 2012
     As for plants, I certainly concede the point that other factors (outside the greenhouse) might negate the benefit of Co2 as an aerial fertilizer. I have read the page and am still on the fence regarding overall cost-benefit analysis regarding the aerial fertilizer argument. But, just as the potential benefits of aerial fertilization is listed in the above pros and cons, I would like to see potential benefit to mitochondrial respiration in fauna listed as well.
258. KR at 11:56 AM on 14 September, 2012
     AHuntington1 - I would point to Gonzilez et al 1996, "Direct lnhibition of Plant Mitochondrial Respiration by Elevated CO2", among others. When considering elevated CO2 it is vital to consider the full spectrum of effects - heat, ocean acidity, C3 versus C4 plant responses, and the fact that other aspects of the environment may be the limiting effects on biology. You claim elevated CO2 is, overall, beneficial - that's really not supported by the evidence available.
259. Stephen Baines at 13:21 PM on 14 September, 2012
     "More CO2 means less O2 is absorbed immediately into the hemoglobin, but the O2 that is picked up is easily distributed." Yes, my point exactly. For all you know, the two things cancel out, or worse. You've provided no real evidence that increasing ambient CO2 has a net positive impact on O2 use efficiency. It could just as easily be a negative impact. In any case, even if you were correct, it is besides the point. As KR notes, the point of the OP is not that increasing CO2 is always bad for everything under all circumstances. It's that, taken together, the effects of increasing CO2 on organisms and human society will be on balance very negative. That's true even when we acknowledge the positive effects of increasing, including CO2 fertilization of plants. By focusing on a few physiological processes, you're missing the forest for a few cherry trees.
260. Dikran Marsupial at 20:02 PM on 14 September, 2012
     AHuntingdon1 I asked you for a peer-reviewed* study that supported your hypothesis that increasing atmospheric CO2 has a significant metabolic benefit. You were only able to provide papers supporting some of the component parts of the hypothesis. Ideally one would like to see the self-skepticism that would be indicated by a straight answer that clearly stated that there were no papers that supported the hypothesis itself. No regarding the obesity paper, as you said I used logic as the basis for my skepticism of that hypothesis. The same logic underpins my skepticims of your hypothesis, I doubt rising background levels of CO2 have a great effect on CO2 levels indoors or in urban environments, where CO2 levels are likely to be determined by local source and sinks. You did not address that issue. If CO2 levels did have a significant effect on metabolism (i) we would be able to see those benefits in human health and (ii) it would be easy to perform the experiments to confirm the link and there would be a paper on the subject by now. *yes, I do know that peer-review is no guarantee of correctness, however it does at least mean that the paper has passed the preliminary sanity check of peer review.
261. Dikran Marsupial at 20:08 PM on 14 September, 2012
     AHuntingdon1 wrote "People at high altitudes breathe less O2 (and Co2), but continue to metabolize glucose, which produces water and Co2. Thus, people at high altitudes are exposed to a higher ratio of Co2 to O2 internally. But yes, the atmosphere is less dense all around." I very much doubt this is correct. The amounts of CO2 produced from glucose metabolism are going to be very small compared with the amounts in the atmosphere already. Unless of course you are indoors in which case CO2 levels are not primarily determined by background CO2 levels and so your initial hypothesis is invalid anyway.
262. anon1234 at 22:53 PM on 14 September, 2012
     Dikran Marsupial, with each breath we exhale something like 35,000 ppm of Co2. A much higher percentage of Co2 than current atmospheric levels. I thought I did say this, but I have not come across any peer reviewed papers that espouse the theory that increases in atmospheric Co2 provide a net benefit. The fact that this study is hard to find/NA does not reflect a lack of evidence on the benefits of Co2 (as there are many studies) as much as it reflects the mentality of most biological scientists (especially nutritionists). ps. It's funny that you spell my name Huntingdon- this was common way to spell the name before words became more standardized. Stephen Baines, but they don't cancel out. The Bohr effect is a bit counter intuitive; A higher Co2 to O2 ratio provides a lower affinity for O2 in the blood, and more ability to transfer O2 to the tissues(plus Co2 is a vasodilator, thus allowing more blood to flow in general). A lower Co2 to O2 ratio provides a higher affinity for O2 in the blood, and less O2 transfer to the tissues (plus O2 is a vasoconstrictor). KR, interesting article. Remember, my claim is that increasing atmospheric Co2 (by any means, to a certain extent) can have positive effects on animals via increased respiratory efficiency. I never made an overall cost-benefit judgement. I just want it added to the list of potential benefits.
263. Bernard J. at 23:04 PM on 14 September, 2012
     AHuntington1 said at #250:

     High altitudes provide a real life example of a population that breathes a higher Co2 [sic] to O2 ratio.

     I'm curious to know on what basis you make this claim. Is the ratio of the partial pressure of carbon dioxide to the partial pressure of oxygen at altitude significantly greater than at lower altitude?

     It is also interesting that people who live in high altitudes (and are exposed to a higher Co2 [sic] to O2 ratio) [sic] experience lower mortality rates, in general.

     I suspect that the phenomenon to which you refer has more to do with the fact that non-essential metabolism is more likely to be reduced at higher altitude. There is a credible suggestion that calorie/joule use (which has an effect on metabolic rate) in humans is proportional to life span, just as it is in so many other species.
264. Dikran Marsupial at 00:39 AM on 15 September, 2012
     AHuntington1 Firstly appologies for mis-spelling your name. Secondly, while exhaled air my be something like 35,000 ppm of Co2, but the volume of a breath is negligible compared to the volume of the atmosphere. The CO2 in exhaled air only has a significant effect on the air we breathe in if we are indoors (this is now the third time I have pointe dthis out), and if you are indoors, CO2 levels are not controlled by the background CO2, but by local sources (such as your exhalations), and hence rising atmospheric CO2 levels will have not have any significant effect on CO2 levels in the room, and hence no significant effect on metabolosim. You claimed that increasing CO2 levels would have beneficial effect on metabolism, but only present evidence that one element of the causal chain can be observed. This is pretty weak evidence, and in my opinion, the way you are presenting your case (i.e. overclaiming and ignoring counter-arguments) does you no favours whatsoever.
265. Stephen Baines at 01:06 AM on 15 September, 2012
     AHuntington "...but they don't cancel out. " This is just an assertion. You haven't provided any evidence. The papers your cite can't be evaluated as they are only abstracts of papers in Russian. You could try to make a theoretical case using heamoglobin-O2 saturation curves, taking into account the effects of ambient CO2 on uptake of CO2 in lungs and tissue CO2. Experimental evidence would be more convincing, however. My guess is that the influence of ambient CO2 variations on O2 uptake in the lungs and release in tissues will be relatively small, and are likely to offset. It doesn't seem sensible that the effect of increasing ambient CO2 on CO2/O2 ratios in the lungs would be smaller than the effect on CO2/O2 ratios in the tissues. I could be convinced otherwise, but I would need to see evidence. You are not really providing any.
266. KR at 01:51 AM on 15 September, 2012
     AHuntington1 - "...my claim is that increasing atmospheric Co2 (by any means, to a certain extent) can have positive effects on animals via increased respiratory efficiency. I never made an overall cost-benefit judgement. I just want it added to the list of potential benefits." I would point to the opening post, which states that

     Negative impacts of global warming on agriculture, health & environment far outweigh any positives.

     You claimed that "More atmospheric C02 is beneficial for plants (as has been described in this thread) and animals" - a statement on net effects. But you have not supported your statement with any significant evidence. In fact, your initial claim of changes in CO2 to O2 ratios improving metabolism appears to be nonsense, which you've abandoned to move on to other arguments/moved goalposts. Again - while there are positive and negative effects from global warming (including the potential effects you have argued, but not supported), the negatives far outweigh the positives.
267. anon1234 at 14:03 PM on 16 September, 2012
     Dikran Marsupial, we are talking about internal exposure to Co2. you said "The amounts of CO2 produced from glucose metabolism are going to be very small compared with the amounts in the atmosphere" and I pointed out that sugar metabolism produces enough Co2 to allow us to exhale roughly 35,000 ppm with each breath(~100 times more Co2 than the air we breathe). Glucose metabolism creates a huge amount of Co2 compared to atmospheric levels- thus we need to exhale. I am not saying that humans breathing contributes any significant amount of Co2 to the atmosphere, but it does significantly effect internal exposure to Co2. Stephen Baines, you are the one who made the assertion that I misunderstood the Bohr effect. The burden of proof is on you at this point, but I will re-post the wikipedia. http://en.wikipedia.org/wiki/Bohr_effect and quote a passage from the link, "hemoglobin's oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide.[1] That is to say, a decrease in blood pH or an increase in blood CO2 concentration will result in hemoglobin proteins releasing their loads of oxygen and a decrease in carbon dioxide or increase in pH will result in hemoglobin picking up more oxygen. Since carbon dioxide reacts with water to form carbonic acid, an increase in CO2 results in a decrease in blood pH." You are the one who has it wrong. Bernard J, see my response to Philippe Chantreau in post #256 on this page. The passage that you quoted was a mis-type on my part, and I have specified the issue. People at high altitudes consistently have higher basal metabolic rates. http://jap.physiology.org/content/16/3/431 Respiratory acidosis is a potential symptom of traveling to high to fast (a sign that Co2 to O2 ratios increase at high altitudes) KR, my only request is that the positive aspects that increased Co2 levels have on animals should be considered in the cost-benefit analysis. My statement is not one of net effects, but of specific effects which should be included in the analysis. Increased Co2 levels, within a certain threshold, do increase crop yields- ceteris paribus - and that potential benefit is taken into account in the above analysis. Likewise the benefits of increased Co2 on fauna and bacteria (within a certain threshold)should be taken into consideration as well.
     Response: [Sph] Correction as per request.
268. anon1234 at 14:09 PM on 16 September, 2012
     KR, you said "your initial claim of changes in CO2 to O2 ratios improving metabolism appears to be nonsense, which you've abandoned to move on to other arguments/moved goalposts." This is totally false. Is improved distribution of O2 to the tissues bad? Does it not improve mitochondrial respiration? Do antioxidants reduce respiratory efficiency? You are simply ignoring my arguments.
269. Bob Lacatena at 15:08 PM on 16 September, 2012
     AHuntington1, You are conflating detailed analysis of CO2 in organisms with the more general inference that these detailed aspects combined with increases in atmospheric CO2 must result in beneficial outcomes. This inference is (a) unwarranted and (b) not in any way supported by actual scientific studies in the literature. Your position is akin to saying that (a) "theoretical physics suggests that tachyons may move faster than light" therefore (b) "faster than light travel is possible and will be achieved in our lifetime." Your assertions do not warrant their conclusion, especially when such a conclusion was (to begin with) as specific as a benefit in "mitochondrial respiration in fauna." Even if this were the case, the claim would be laughable. As the dying man crawls through the desert, parched by drought, weakened by hunger and baking in the heat, you can cheerily say to him "yes, but aren't your cells respiring so much more comfortably in this atmosphere?"
270. anon1234 at 17:14 PM on 16 September, 2012
     Sphaerica, no I am not. I said all else being equal -ceteris paribus- increases in atmospheric Co2, within a certain threshold, has been shown to have beneficial effects on plants (which has been thoroughly hashed out) and animals (through Co2's role as an antioxidant, vasodilator, and protector of the body's O2 supply). Evoking the image of a man suffering from sever dehydration and starvation in the desert is completely irrelevant and blatantly panders to the most basic of human emotions. This behavior is totally inappropriate in a scientific debate.
271. Dikran Marsupial at 00:42 AM on 17 September, 2012
     AHuntington I have now pointed out the same flaw in your argument several times (namely that background CO2 levels don't have much of an effect on CO2 levels where we actually live), and each time you have studiously ignored it. You have not shown that increasing atmospheric CO2 levels have a beneficial effect on animals in vivo. Increasing internal CO2 having a beneficial effect on mitochondrial respiration does not establish that rising atmospheric CO2 has a beneficial effect on animals because (a) you have not shown that rising atmospheric CO2 leads to significantly higher internal CO2 (b) you have not shown that increasing mitochondrial metabolism is necessarily beneficial. However, I suspect you will duck this point yet again.
272. Stephen Baines at 00:46 AM on 17 September, 2012
     AHuntington You yourself acknowledged @256 that, according to the Bohr effect, increasing CO2 would decrease O2 uptake in the lungs. Until you can explain to us why that does offset the effect of increased O2 loss from haemoglobin to tissues, I can't see why I should accept your claim. We cannot evaluate your evidence because we cannot read those papers. Can you read them? It would not be skeptical of us to simply take your word.
273. John Hartz at 06:48 AM on 17 September, 2012
     @AHuntington1 #270: Whenever I see a commentor such as yourself use the term, "scientific debate" alarm bells go off. Are you here to learn more about the science or to play a "Gotcha" game with whomever deigns to question something that you have posted?
274. Bob Lacatena at 08:02 AM on 17 September, 2012
     AHuntington1, Yes, but "all else being equal" doesn't at all apply in this case, so what's the point of the entire line of thought, except to beat a dead horse or to mislead the unwary? As far as what is appropriate to a scientific debate... you say this as if you are being perfectly rational and even in your approach, which clearly you are not. Your posts are full of debate tricks (not the least of which is an excess and as yet unearned degree of hubris). Your position is categorically untenable. You Gish Gallop a lot, "speaking" with an authoritative "I know, listen to me, children" tone, but you prove absolutely nothing. In the end, you expect people to accept your position simply because you declare it to be true. Fact: Increased CO2 levels, while beneficial in some cases, are not that beneficial. Fact: Different plants respond better than others to increased CO2... are you sure that it will be productive crops and not the weeds that really enjoy the elevated CO2 levels? Fact: Water availability is far more important. Droughts, expanding deserts and other ramifications of climate change will be far, far more important than whatever meager benefits are derived from "improved mitochondrial respiration" in some plants. Fact: Temperature is far more important. Increased temperatures, which change the range of temperatures that impact a plant in various seasons, will be far, far more important than any benefits derived from increased CO2. You have failed to prove your point, and your point amounts to sleight of hand... if climate change doesn't raise temperatures, increase droughts, and drastically change agriculture on the planet, the increase in CO2 will be great!
275. anon1234 at 10:03 AM on 17 September, 2012
     Dikran Marsupial, i did miss that point; I also never mentioned that humans who live in cities/ use air conditioning would be the primary organism to benefit from elevated Co2. If Co2 levels are significantly elevated in cities and/or houses with ACs the organisms who would primarily benefit from increased atmospheric Co2 would be those furthest from modern development. Rising atmospheric Co2 does increase internal exposure to Co2 (as soon as a person becomes acclimated, and stops hyperventilating); the internal Co2 level is affected by atmospheric conditions and rate of breath. This is seen when people are acclimating to higher altitudes- increasing internal Co2 can cause temporary respiratory acidosis, or hyperventilation can cause respiratory alkalosis. Once people become acclimated they breathe normally, increase internal Co2 to O2 ratios and become more efficient sugar metabolizers (lactate paradox). If you think that mitochondrial efficiency is not beneficial, I don't have much to say. Do you really think that less ATP is better than more? Look at the higher metabolic rates of people living at high altitudes and the epidemiological data regarding these people. One positive example is the generally lower mortality rates among them. This is good evidence to support the hypothesis that a higher metabolic rate is beneficial. Stephen Baines, you said "explain to us why that does offset the effect of increased O2 loss from haemoglobin to tissues" Because the tissues will always be more oxygen starved, and acidic than the lungs and the blood that just pick up O2. Therefore the freshly oxygenated hemoglobin in a higher Co2 environment will always be able to pass oxygen to the tissues (which by definition, must always have less O2 and more Co2 or acidity than the freshly oxygenated blood and lungs). John Hartz, I wasn't playing "gotcha". He attacked a big straw-man, and then painted a picture of me literally mocking a starving and dehydrated human being crawling through the desert. If Sphaerica wasn't displaying an irrelevant appeal to petty emotionalism, I have never seen one- and that behavior is not appropriate in any discussion, let alone a scientific one. Sphaerica, I do not "Gish Gallop" alot. The facts that I present are completely relevant to the points I am making. If you can't understand how, I recommend re-reading my posts, and learning about metabolism (and logic). Fact 1 is clearly your opinion (as ultimate ends, and values are not scientifically testable). Fact 2 is true, but irrelevant. Fertilizer and water also "help weeds too", would you recommend eliminating their use in agriculture? Fact 3 is true, but also irrelevant as I did say all else being equal (I have been repeating this to no avail). Ditto for fact 4. Basically I am getting tired of repeating myself and defeating straw-men. Everyone else seems capable of rational discussion; why are you constantly changing the subject? you said "if climate change doesn't raise temperatures, increase droughts, and drastically change agriculture on the planet, the increase in CO2 will be great!" ..then we basically agree, and you will stop posting strawmen, yes?

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