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Comments 88201 to 88250:

  1. More Carbon Dioxide is not necessarily good for plants.
    @ 17 Johnd: Whats going on here? I earlier posted a response to the recently created (April 14th) "CO2 is plant food" thread, and instead of responding, the author then duplicates his claims made there in a this brand new thread. I know there is a redundancy Johnd but that is not due to anything I did. This is the first thread that I noticed, so I've been here all along. If there's a problem you can take it up with one of the moderators or John Cook.
  2. More Carbon Dioxide is not necessarily good for plants.
    "You're saying that increased atmospheric CO2 caused the increases in 20th century agricultural productivity? " Noooo, I'm just saying it didn't prevent it. "The FF-powered tractor has caused a tremendous increase in agricultural productivity in the last 100 years. FF have also allowed for the cheap production and delivery of pesticides and herbicides, advanced seeds (I should say "advanced" when I think of Monsanto), and advanced agricultural machinery. I think--and I'm just guessing here (sorry scientists)--that such things far outweigh any currently theorized positive effect of CO2 on plant growth where agricultural productivity during the 20th century is concerned." and yet the idea is to suppress FF ... to avoid CO2 to hinder productivity ... ??
  3. More Carbon Dioxide is not necessarily good for plants.
    @1 Gilles: " wonder why Nature has managed to make an increase of average temperature bad for everything. Isn't it quite unlikely ?" "Why am I not surprised that Gilles would be the first commenter on my post? No, it's not going to be bad for everything. Just those things that survive. It'll only take a few tens of thousands of years for evolution to enable plants that don't fair well with increased CO2 (Assuming they don't become extinct for ther AGW related issues). "especially for agriculture,it is quite weird because each plant has a favorite biotope, so the productivity cannot be a universal decreasing function of the local average temperature. So it must be somewhere optimal. But changing temperature should only displace the location of the optimum. Well it could be that this displacement is unfavorable, but also it could be the opposite. How do you explain that it seems to be *universally* unfavorable, everywhere? and if not, how can you properly compute an average trend, and know whether the benefits are larger than drawbacks or the opposite ?"(Underlining mine) You seem to be on both sides of the fence as to the favorability/unfavorability of biotope shifting on agriculture. At least we agree that changing the temperature will shift the location of where the crops would grow (optimally, of course). It's real simple. How many 100s of millions of people are going to be migrating northward (in a civilized manner, of course)? "you seem to possess some kind of science I'm totally ignoring ...." Science? This is actually in the realm of common sense deductions based on the conclusions of science.
  4. More Carbon Dioxide is not necessarily good for plants.
    Gilles: "Excuse me, but am i wrong or in the past century, CO2 concentrations, temperature, and agricultural productivity have all increased together ? is it not a definite proof that it cannot always be true that increasing CO2 will be bad 'on balance'?" I'll bite by stating the obvious counterargument: You're saying that increased atmospheric CO2 caused the increases in 20th century agricultural productivity? Unintentionally, of course, you are correct. The FF-powered tractor has caused a tremendous increase in agricultural productivity in the last 100 years. FF have also allowed for the cheap production and delivery of pesticides and herbicides, advanced seeds (I should say "advanced" when I think of Monsanto), and advanced agricultural machinery. I think--and I'm just guessing here (sorry scientists)--that such things far outweigh any currently theorized positive effect of CO2 on plant growth where agricultural productivity during the 20th century is concerned.
  5. More Carbon Dioxide is not necessarily good for plants.
    Vegetation was carbon-free in 1860 ???
  6. Berényi Péter at 06:34 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    "Increasing CO2 levels would only be beneficial inside of highly controlled, enclosed spaces like greenhouses". I see. This is why global carbon content of both soil and vegetation is increasing exponentially during the last 150 years. In spite of widespread destruction of woodland. Sounds plausible.
    Response: [DB] Those wishing to see the original, in-full-context version of BP's above graph can find it here: http://maps.grida.no/go/graphic/carbon-stocks-trends-and-projections-compared-to-1860.

  7. More Carbon Dioxide is not necessarily good for plants.
    "Increasing CO2 brings with a very large number of changes. Some are good, and some are bad. But the best estimates at quantifying the good and bad show that the bad is far greater than the good." It's just about plant growth here - and it's not "scenarios", just known facts :CO2 has increased, and agricultural production has increased as well.
  8. More Carbon Dioxide is not necessarily good for plants.
    This is an interesting topic. I get the feeling that several aspects may have been glossed over (as necessary for a blog post) -- one of these is the conclusion that more water will be necessary for plants in a higher CO2 world. Because the stomata won't need to be open so long (due to the higher CO2 availability), there will be less evapotranspiration per carbon molecule fixed. At least, that's one hand-waving argument. Has this been worked out in detail?
  9. What was it like the last time CO2 levels were this high?
    Dikran; not a problem. However my name is Villabolo not Villalobo. "Lobo" means wolf in Spanish.
  10. Michael of Brisbane at 06:04 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    "Plant defenses go down as carbon dioxide levels go up, the researchers found. Soybeans grown at elevated CO2 levels attract many more adult Japanese beetles than plants grown at current atmospheric carbon dioxide levels." Perhaps, to look at it another way, it's not the plants "defenses" that go down, but the plants "appeal" that goes up? Perhaps a healthy plant is more attractive to an "adult Japanese Beetle" than an unhealthy one starved of CO2. Perhaps a healthy plant would appeal to beetles of every nationality and not just Japanese ones? Perhaps it would mean that a well-fed Japanese beetle would be more appealing to a Japanese birdy? Perhaps the whole food chain would be more healthy? Perhaps increased CO2 is good for ALL life on earth?
  11. More Carbon Dioxide is not necessarily good for plants.
    I do think that this argument could be expressed in terms 'denialists' can understand because they use them so often: The impact on vegetation his highly uncertain, to predict it one would have to depend on models, the measurements of vegetation, globally, are incomplete and historically depend on proxies... bla bla bla... we can't know if increasing CO2 is good or bad, there's uncertainty and consequentially we should do everything to stop adding CO2 to the atmosphere. :)
  12. More Carbon Dioxide is not necessarily good for plants.
    For everyone else I suggest a quick brush up on Liebig's law of the minimum which states that plant growth is controlled not by the total amount of resources available, but by the scarcest resource. Or in other words, no amount of CO2 will turn the Sahara green
  13. More Carbon Dioxide is not necessarily good for plants.
    Change apparently affects diversity. I remember reading a recent study addressing why there is so much more species diversity in the tropics as opposed to temperate climates. The conclusion of the study was that the absence of seasons promoted diversity. Even though seasons move in a generally predictable manner, the annual changes were still enough to discourage species diversity. Change by itself seems to be enough to powerfully affect how many species will survive. Thus adding CO2 quickly to the environment, changing the amount of water falling or the amount of water available, changing temperature ranges, etc., should be expected to lower diversity in the short term. In the long term, nature can be expected to adjust, once the changes stop. That may be in hundreds or thousands of years, Gilles. So do we put our civilization on hold until then, or stop the worst of it now?
  14. More Carbon Dioxide is not necessarily good for plants.
    @ Gilles "it cannot always be true" Sure I could construct a scenario where CO2 increases are on balance positive... but that scenario would be markedly different from what we are currently experiencing. So you point is completely irrelevant. Increasing CO2 brings with a very large number of changes. Some are good, and some are bad. But the best estimates at quantifying the good and bad show that the bad is far greater than the good.
  15. The Scientific Guide to Global Warming Skepticism
    It might make sense to replace your Fingerprint #1 with this site's argument that extra CO2 comes from oxidation of fossil fuels (to which I just posted a comment about fixing broken URLs). The falling-O2 argument may be easier to understand. Also, the O2 argument makes a stronger claim, that O2 is going down by the same amount that CO2 is going up.
  16. CO2 is coming from the ocean
    This is a great argument. The two IPCC URLs have expired; here's the new URLs: AR3WG1 Section 3.5.1 Figure 3.4
  17. More Carbon Dioxide is not necessarily good for plants.
    Re " any number of catastrophic scenarios can be attributed to "excess" CO2 and not one single positive benefit has been presented. The article is simply being true to the headline: "Too much of a good thing is a bad thing. Increasing Carbon Dioxide, as 'plant food', is not good for plants." Elsewhere on SkS both the pros and cons of increasing CO2 and temperatures have been discussed-- sorry, but cannot find that link right now. The science and body of evidence strongly indicate the the cons far outweigh the pros, for a net negative impact on agriculture and ecosystems and ultimately us.
  18. Berényi Péter at 05:18 AM on 18 April 2011
    Solar Hockey Stick
    "The solar radiative forcing is the change in total solar irradiance (TSI) in Watts per square meter (W/m2) divided by 4 to account for spherical geometry, and multiplied by 0.7 to account for planetary albedo" TSI is not a particularly good climate indicator. UV-A (between wavelength 320 and 400 nm) is better, because
    1. solar variability is much larger in the UV than in the visible or near infrared
    2. the atmosphere is pretty transparent to UV-A, because it does not fall into the O3 absorption band
    3. water is extremely transparent for UV-A, so this kind of radiation can penetrate into the ocean (down to several hundred meters) and deposits its energy there as heat
    As UV heating of seawater occurs at a lower geopotential than evaporative and radiative cooling (which happens right at the surface), UV heating, unlike thermal IR, contributes to ocean mixing. It means the effect of increased UV irradiation has a delayed effect on temperature, as heat capacity of oceans is enormous compared to any other part of the climate system. Unfortunately UV-A variability is not well constrained by measurements.
    Absorption Coefficient of Water
  19. More Carbon Dioxide is not necessarily good for plants.
    Villabolo, making an argument that CO2 is merely plant food is understating the fact. Carbon is a fundamental building block for all life forms, plants being about 45% carbon, whilst animals including humans are less than 20%. Interestingly, by comparison the carbon content of coal ranges from about 30% in low rank coals such as lignite to 45% to 85% for the most used form of bituminous coal, up to to 98% in anthracite. However what I am interested in is the statement "Higher concentrations of CO2 also reduce the nutritional quality of some staples, such as wheat." Are you able to quantify both the reduced nutritional quality along with any associated increased yields as determined by the better performing varieties that have been tested in open field trials under enriched CO2 conditions? Apart from that, some points in the OP are confusing and in apparent conflict. For example, the concerns made about the extra requirements of plants bought about by increased CO2 becoming a limiting growth factor, seems to have been overcome by point 3 where resultant denser vegetation apparently creates increased fire risk. What position is being asserted, less growth due to various limiting factors, or denser growth?
  20. More Carbon Dioxide is not necessarily good for plants.
    Whats going on here? I earlier posted a response to the recently created (April 14th) "CO2 is plant food" thread, and instead of responding, the author then duplicates his claims made there in a this brand new thread. ???
  21. More Carbon Dioxide is not necessarily good for plants.
    "there is good reason to think that rises in CO2 may well be bad on balance for plant life." "The ecosystem is undergoing multiple deep, broad, and rapid changes (habitat destruction, rapid warming, increasingly acid oceans from CO2, other forms of pollution, migration interference, water availability changes, colonization and destruction of "food animals"--fish, cows, pigs, et al.-- etc.), and you say it's unlikely that it's all bad?" Excuse me, but am i wrong or in the past century, CO2 concentrations, temperature, and agricultural productivity have all increased together ? is it not a definite proof that it cannot always be true that increasing CO2 will be bad "on balance"? (I think you will agree that in simple logics, it is enough to find a single counterexample to show that a thing is not always true?) So if it is not always true, do you know a little bit more specifically under which conditions it will be true ? stating that it "may" be wrong (or true) is of course not falsifiable. But do you have a more precise idea of what it will be - and when ?
  22. More Carbon Dioxide is not necessarily good for plants.
    15 Seaward - Possibly a good point, possibly not. May I suggest you present some documented evidence of how plants do better with higher levels of CO2 - what those levels are, what other factors (water supply, nutrients etc.) are required to support that advantage, etc. With a few decent references, I'm sure it'd be a good contribution.
  23. Harry Seaward at 04:15 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    This article makes a lot of predictions as if they were proven fact. That is not the case. I am amazed that any number of catastrophic scenarios can be attributed to "excess" CO2 and not one single positive benefit has been presented.
  24. Clouds provide negative feedback
    Daniel (RE: 20), "I in no fashion mean to downplay your sincerity in your beliefs from what you've learned from G White and the like. In order to help you better convey your position with greater clarity, I suggest you learn to better discern the point between where established physics and that you've learned from Mr. White diverge. If you can serve that divergence up with clarity and precision, I think then that others will be better able to understand you. It will necessarily entail (as Sphaerica has pointed out with greater eloquence than I), however, temporarily setting aside those learnings and preconceptions gained from the table of Mr. White to leap into mainstream physics deep enough to better educate yourself on where that difference lies, so you can then relate that point to others." Where does the difference between "established physics" lie ? This is what I don't understand. These kinds of responses are not scientific discussion - they're just empty platitudes. Yes, it's no secret I've spent a considerable amount of time studying GW's research and he has been very generous to me. However, I am not "accepting" his research on the basis of his authority or generosity toward me (nor, I'm sure, would he want me to). I've largely accepted it by examining it in detail and weighing it against all the other evidence. But look, I'm not here to discuss GW - I'm here to discuss cloud feedbacks, and would like to get back on topic and return to scientific give and take discussion.
  25. More Carbon Dioxide is not necessarily good for plants.
    Gilles It's not bad for everything. It's good for the pests, as the article said. On a separate note, perhaps a good response to the 'plants will absorb the extra CO2 as it is plant food" is to point out that the level of CO2 has demonstrably risen, which means the plants are not aborning the 'excess'. And there has been no massive increase in plant fecundity in the past 100 years, besides that attributed to the use of modern farming techniques. So exactly when are the plants expected to take advantage of this free food bonanza?
  26. More Carbon Dioxide is not necessarily good for plants.
    Gilles (@ #1), according to evolutionary development, life adjusts as well as it can (given its existing forms in any historical moment) to changing conditions. If the changes come slowly and are limited in space, many forms have the chance to adapt. If the changes come rapidly and are general, some forms are unable to adjust, and they become extinct. Feedbacks then occur in the food chain. Now consider the number and changes (and their breadth and depth) brought about by the rapid expansion of the human population in a mere 200 years. The ecosystem is undergoing multiple deep, broad, and rapid changes (habitat destruction, rapid warming, increasingly acid oceans from CO2, other forms of pollution, migration interference, water availability changes, colonization and destruction of "food animals"--fish, cows, pigs, et al.-- etc.), and you say it's unlikely that it's all bad? And Gilles, "god" - really? Good grief. *looks at watch* God's late. Should we start without him?
  27. Muller Misinformation #3: Al Gore and polar bears
    chriscanaris, you might want to reconsider holding up the 'stability' of the Southern Hudson Bay population as evidence that, "the whole business might be complex than at first sight". [sic] Based on deteriorating bear weight and other observations, that sub-population is currently listed as 'very likely' (i.e. 80-100%) to decline in the future. That from the same studies, by the IUCN Polar Bear Specialist Group, as the population trends you (and the map above) cite. If you look at the circle sizes and accompanying legend on the map you'll also see that we are talking about a relatively small number of bears... as compared to the many larger circles found amongst groups that are in decline.
  28. Dikran Marsupial at 03:37 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    Gilles@9 You are over-interpreting the article again. The point it makes is that "CO2 is plant food" argument is over-simplistic, and that if you look at the next level of detail up, there is good reason to think that rises in CO2 may well be bad on balance for plant life. The article does not address the next level of detail up from there, which would be to do the research needed for a global study from which you could estimate a budget. There is a good reason why not, which is that the "CO2 is plant food" is adequately dealt with by qualitative arguments that demonstrate that it is simplistic. There is also the fact that the research is the task of the research community, the task of SkS is communication of that research to the general public and to provide a forum for members of the general public to discuss it at an appropriate level of complexity. Now as I said, if you are interested in budgets etc., go and find them for yourself and let us know what you find. We will be interested to hear about it.
  29. graphicconception at 03:34 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    "Plants cannot live on CO2 alone." Agreed. "They get their bulk from more solid substances like water and organic matter." As I understand it, they get approximately half their "bulk" from Carbon. Much of the rest comes from Oxygen.
  30. More Carbon Dioxide is not necessarily good for plants.
    OK so is your point that despite the increase of CO2, the overall productivity could decrease at some places ? or is it that the aggregated effect all over the world will be negative, because you can make an overall budget of all possible positive and negative effects everywhere ?
  31. Robert Murphy at 03:08 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    Giles, #4: "Obviously agriculture is a complicated aggregation of several things , very variable locally - temperature, rains, ground chemical composition, CO2, parasites ... " Which is why the claim "More Co2 will be good for plants" is so wrongheadedly simplistic. It ignores everything else that also affects plant growth. "So you wouldn't expect that a CO2 increase is bad *everywhere*" Nobody said it was.
  32. Dikran Marsupial at 02:52 AM on 18 April 2011
    More Carbon Dioxide is not necessarily good for plants.
    Gilles@4 The article does not say that "everything goes wrong", just that CO2 is only beneficial "plant food" if conditions are right (i.e. growth is not limited by water supply, soil quality or pests). However the rise in temperature expected due to the rise in CO2 is likely to reduce water supply in many places, reduce soil quality and benefit pests. That means on balance, the additional carbon dioxide is likely to be bad for plants. That does not mean that there will not be any plants that will benefit from the additional CO2. God doesn't hate us so much, the natural environment is increasingly the way we have made it, the responsibility is ours.
  33. Daniel Bailey at 02:49 AM on 18 April 2011
    Clouds provide negative feedback
    @ RW1 In the interest of fairness I offer some (unsolicited) advice: I in no fashion mean to downplay your sincerity in your beliefs from what you've learned from G White and the like. In order to help you better convey your position with greater clarity, I suggest you learn to better discern the point between where established physics and that you've learned from Mr. White diverge. If you can serve that divergence up with clarity and precision, I think then that others will be better able to understand you. It will necessarily entail (as Sphaerica has pointed out with greater eloquence than I), however, temporarily setting aside those learnings and preconceptions gained from the table of Mr. White to leap into mainstream physics deep enough to better educate yourself on where that difference lies, so you can then relate that point to others. At that point you should also be then able to construct tests for your hypothesis that can then be examined by others. In short, you will have a publishable basis for submission to peer-review. HTH, The Yooper
  34. What was it like the last time CO2 levels were this high?
    [inflamatory comments deleted] I'm far more interested to know whether or not we have a good idea how much ice there was before the temperatures started rising during the Pliocene? Also, a recent study claims that the current CO2 levels are the highest in 15 million years, see here. If that is true, as are the findings discussed by Bart Verheggen here, then I really do not see much reason for the optimism and glib attitude shown by our dear contrarians.
    Moderator Response: [Dikran Marsupial] Please see the comment on Villalobos' post; the discussion is best served if we all keep the tone neutral, whatever the perceived provocation.
  35. More Carbon Dioxide is not necessarily good for plants.
    "The initial post contains reasons, references, and data supporting the premise" AFAICS, the initial posts contains a short list of possible reasons that could go worse. This is neither exhaustive, nor limitative. There is no figures associated. No possibility of doing any budget. No experimental validation on a global scale. I can't see how to draw a general conclusion from that ..
  36. More Carbon Dioxide is not necessarily good for plants.
    KT there is no assertion - except I'm surprised by the general result - that everything goes wrong. Obviously agriculture is a complicated aggregation of several things , very variable locally - temperature, rains, ground chemical composition, CO2, parasites ... Under some conditions, CO2 is actually used to improve the growth. So you wouldn't expect that a CO2 increase is bad *everywhere* Do you think that God hates us so much ?
  37. Debunking Economic Myths from the Climate Hearing
    WSteven @12, "I know that they've done some things, but the Conservative Party of Canada still have a long ways to go" Too true. There have been some attempts at green washing, but not much else. Some huge oil sands projects will be coming on line soon. The projections for oil production from the tar sands are up and up and up (I need to substantiate that I know, will do that, but I happen to know people on the "inside"). And let us not forget that Harper et al. are mostly from the old Alliance party....scary. That said, let us not write them off, but let us be realistic. Someone needs to hold their feet very close to the fire. It could be that Canada faces sanctions of some sort down the road....you never know, but that is what it might take. Either way, to get back to the topic of this post, it seems to me that the uncertainties in the economic models are far greater than those form the climate models, yet some consistently try and use some obscure economic figures to claim devastating economies and the such so as to encourage FUD. The interesting thing about economic models, the results are dependant on the many assumptions that you need to make. Someone managed to demonstrate that buying a hummer was actually better for the environment than a Prius (sorry cannot recall the details), and they did, but had to choose some wildly unrealistic assumptions to do so. Climate models ont he other hand are constrained by physics, yes their is uncertainty, but one cannot assume that pi=4.0 or "tune" the stefan-Boltzmann constant or the radiative forcing from each GHG. And what is more, one can quantify the uncertainty. With that all said, what we need are more full cycle studies and more studies which incorporate the social and environmental costs of using the available energy sources, such as the paper Dana discussed on the SCC.
  38. Rob Honeycutt at 02:33 AM on 18 April 2011
    It warmed just as fast in 1860-1880 and 1910-1940
    Excuse me... Four periods that were statistically significant.
  39. Rob Honeycutt at 02:29 AM on 18 April 2011
    It warmed just as fast in 1860-1880 and 1910-1940
    Andrew... He provided three trends that were statistically significant. That's not the same.
  40. More Carbon Dioxide is not necessarily good for plants.
    I often use the analogy of extra calories. How's that McDonalds diet working out for the average American's health? I agree that a simplistic view that rising CO2 is good for plants, without taking into account other nutritional requirements not to mention the effects of climate change on trees is a willfully obtuse denier tactic. On the other hand, the FACE experiments do show increased growth in the field, as does this study from the Smithsonian. http://www.sciencedaily.com/releases/2010/02/100201171641.htm Unfortunately, what the FACE results find, and my own investigation into that Smithsonian research (posted here http://witsendnj.blogspot.com/2010/04/serc-sucks.html) indicate is that any boost in growth is more than offset by stunting from concurrent rises in the level of background tropospheric ozone. Ozone results from the same processes of burning fuel that produce CO2 and climate change. Ozone is itself a greenhouse gas but even more significantly, it is toxic to vegetation. It reduces annual crop yield and quality by anywhere from 20% to 80%, according to various international agencies, making this an urgent problem right up there with ocean acidification. Trees exposed to cumulative damage season after season are dying at a rapidly accelerating rate. Without trees as CO2 sinks, climate change will lurch ahead in very hazardous ways. Many studies link increased damage from secondary attacks from insects, disease and fungus as well as storm and drought to ozone, not CO2. Here is an excerpt from an article about FACE (Free Air Carbon Dioxide Enrichment) program in Wisconsin: http://www.admin.mtu.edu/urel/news/media_relations/49/ The trees of the future may be much more vulnerable to a variety of pests, say scientists studying greenhouse gases in northern Wisconsin forests. Their work is published in the Nov. 28 edition of the journal Nature. Researchers in the Aspen FACE (Free-Air Carbon Dioxide Enrichment) Experiment, based in Rhinelander, Wis., have been measuring the effects of elevated levels two greenhouse gases, carbon dioxide and ozone, on aspen forest ecosystems. While the trees, Populous tremuloides (trembling aspen), seem to do relatively well in a carbon dioxide-rich atmosphere, ozone is another story. Trees growing in an ozone-enriched atmosphere have been hit much harder by their traditional enemies: forest tent caterpillars, aphids and the rust fungus Melampsora. "This has been a surprise," said Professor David Karnosky of Michigan Technological University's School of Forest Resources and Environmental Science, a principal investigator on the Aspen FACE project. "Our experiment was never meant to look at pest occurrence. But it became obvious that the greenhouse gases were affecting the abundance of pests." Ozone seems to be a special blessing to aphids. Not only did the tiny insects thrive in high-ozone air, populations of aphids' traditional predators--such as ladybugs and spiders--plummeted. "The aphids had free rein," noted Caroline Awmack, an Aspen FACE researcher from the University of Wisconsin, Madison, Department of Entomology. Studies have shed some light on why the aspen growing in ozone-rich air were turning into so much bug salad: their leaves seem to be undergoing fundamental changes. "Ozone alters the surface waxes," said Kevin Percy, a research scientist with Natural Resources Canada--Canadian Forest Service, who is the lead author of the Nature article, "Altered Performance of Forest Pests under Atmospheres Enriched by C02 and O3." The number of aphids increased about five-fold in plots with elevated ozone, while the number of aphid predators was cut in half. In plots with elevated levels of both carbon dioxide and ozone, the aphid population tripled, while the number of natural enemies increased slightly, mitigating the aphids' effect on the aspen. Melampsora infection in the control and CO2-enriched plots was about the same, but increased about 400 percent in the O3 plots and doubled in the plots with extra CO2 and O3. The number of forest tent caterpillars increased by about one-third in the O3 plots and actually decreased slightly in the CO2 plots and the plots with extra CO2 and ozone. Links to more research can be found here: http://witsendnj.blogspot.com/p/basic-premise.html
  41. Muller Misinformation #3: Al Gore and polar bears
    Chris @11, Here you go.
  42. More Carbon Dioxide is not necessarily good for plants.
    My oh my, Gilles - your trolling is becoming more and more blatant. The initial post contains reasons, references, and data supporting the premise. Your post contains vague handwaving, zero references, and indicates that you have either not read the initial post or references, or are completely and deliberately ignoring them. Assertions without evidence can be dismissed without evidence - your post is content free, trolling, and should be treated as such. DNFTT.
  43. More Carbon Dioxide is not necessarily good for plants.
    I wonder why Nature has managed to make an increase of average temperature bad for everything. Isn't it quite unlikely ? especially for agriculture, it is quite weird because each plant has a favorite biotope, so the productivity cannot be a universal decreasing function of the local average temperature. So it must be somewhere optimal. But changing temperature should only displace the location of the optimum. Well it could be that this displacement is unfavorable, but also it could be the opposite. How do you explain that it seems to be *universally* unfavorable, everywhere? and if not, how can you properly compute an average trend, and know whether the benefits are larger than drawbacks or the opposite ? you seem to possess some kind of science I'm totally ignoring ....
  44. It's albedo
    RW1 - "Remember, I agree the physics supports a likelihood of some effect (i.e. some warming) from 2xCO2. I'm mainly disputing the magnitude of 3C predicted by the AGW hypothesis." About 1.1C from a doubling of CO2, estimate of about 3C from feedbacks, so this is an issue you have with feedbacks, best addressed on the relevant How sensitive is our climate thread. It's well worth keeping in mind that this is a boundary value issue. Increasing greenhouse gases barely affect incoming radiation at all, but greatly reduce outgoing radiation. Equilibrium isn't reached until the outgoing matches incoming. And that is what drives surface temperature changes.
    Moderator Response: Yes, and not just "best" addressed, but "must" be addressed on that other thread or other threads that are more appropriate than this.
  45. The e-mail 'scandal' travesty in misquoting Trenberth on
    @Ken #129 uhu? I don't think so. The fact is it looks that the new treasure hunt is getting a paper that states a cooling-warming of the oceans from any 4 or 5 years in a row within the last decade that states an average from -2 to 1.6W/m2 in 0.05 increments. It's just a matter of time -and a research of academical resources including those outside public access WWW- that you'll find the paper with the value of your choice. The Knox & Douglas paper was why I suggested -to others- the exercise in #128 -the exercise predates the paper-. I have to thank you for that paper because it's now in my database for critical thinking in Statistics. Take a look to figure 1 there and tell me what you see. Neither BP nor you contributed one of many papers revealing a heat gain in deep oceans for recent years, specifically in southernmost basins. Why? Is some cherry-paper picking out there? Some kind of "editorialized" line of evidence? The papers I was referring in a previous comment are related to the travesty as Trenberth meant it. The papers you picked are related to the a supposedly independent line of evidence "confirming" the 'climategate' paraphernalia. The matter continue to be "the travesty", as that's the topic of this post and these comments. I suppose people interested in that already discussed the real cooling parts -there are those, I've been discussing about that since 2007- of the supposedly cooling trend and what causes it, all within the other post you listed.
  46. It's not bad
    Gilles#113: "since the average population, ... growth has been positively correlated to temperature" Seeing something in such correlation is specious at best; at worst, it leads to yet another faulty conclusion based upon simple-minded extrapolation. One could just as easily say that population growth correlates well with a stable range of temperatures, or more importantly, a near-zero rate of change of temperature. Once out of that range or in excess of that rate of change, you have no further correlation. Another factor that is obscured by your faulty use of correlation is how interdependent the world is now. During the LIA for example, malnutrition in Europe did not necessarily impact the quality of life in Central Asia. In today's world, a problem in one continent has drastic implications on conditions around the world.
  47. Muller Misinformation #3: Al Gore and polar bears
    According to the World Wildlife Fund (2009): Several polar bear populations were decimated by unsustainable hunting by European, Russian and American hunters and trappers from the 1600s right through to the mid-1970's. In 1973 commercial hunting was strictly regulated following the signing of an international agreement on polar bear conservation. Moreover: Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range, and in some places in roughly their natural numbers. Although most populations have returned to healthy numbers, there are differences between the populations. Some are stable, some seem to be increasing, and some are decreasing due to various pressures. There are large uncertainties regarding some populations that are still harvested quite heavily and others for which information is lacking. As you can see from their map, which you can access on the World Wildlife Fund site (alas, my best efforts to post the image have been to no avail): 1 population is increasing, 3 populations are stable, 8 declining, and 7 data deficient. I don’t question the consensus that habitat loss would be a major threat to bear numbers at least in areas in which hunting is strictly controlled because polar bears strong preference for hunting seals on sea ice. A recent Nature study, for example, predicts decreasing litter size with earlier sea ice melt in west Hudson Bay suggesting this could affect about 30% of the polar bear population. However, the authors sensibly caution that much depends on assumptions about sea ice behaviour, discussion of which clearly belongs on another thread (but yes, I do know Hudson Bay did not freeze over completely last winter). Moreover, their study is based on predictive modelling flowing from the observation that approximately 28% of pregnant females failed to reproduce for energetic reasons during the early 1990s. They note: Historically, polar bears came ashore in early August, but because of rising temperatures sea ice break-up has been occurring about 7–8 days earlier per decade in recent years. Polar bear on-shore arrival has shifted accordingly, resulting in shortened on-ice feeding and prolonged on-shore fasting. The authors also note limitations in their study: However, on-ice feeding rates are unknown for Hudson Bay, and it is also unclear how these rates vary seasonally. They then acknowledge assumptions in their modelling which might both overestimate and underestimate litter sizes. Returning to our map, I note that the west Hudson Bay population is declining but the adjacent Southern Hudson Bay population appears stable. The disparity between adjacent regions suggests the whole business might be complex than at first sight. Historically, the climate even in the West Hudson Bay area has shown considerable variability. Hence, Dyck et al (2007) write in Ecological Complexity: Finally, we wish to encourage a renewed archaeological search for information related to polar bear population ecology from 1760 to 1820, when historical evidence (based on early thermometers at trading posts of Churchill Factory and York Factory) suggests that the climatic regimes at WH had shifted from temperate to arctic conditions …. Ball (1983, 1986) documented large changes and abrupt shifts in both floral (i.e., treeline boundary between the boreal forest and the tundra) and fauna (i.e., migration of wild geese) ecosystem responses of the Hudson Bay region that occurred naturally as a consequence of the varying mean locations of the Arctic Front …. I appreciate that some of the authors of the latter study, which is also a little old, might not be universally popular on this site but so be it.
  48. A Flanner in the Works for Snow and Ice
    Ken Lambert @73, during the summer months of 2010, there was (more than) 2 million square kilometers less ice than during equivalent summers thirty years ago. The sunlight falling on water that would have fallen on ice in 2010 did not heat the water over the intervening years. It only heated it in 2010. Therefore there is need to divide the 1.51*10^21 Joules by 32. That is the additional amount of energy each summer that would not have been absorbed except for the reduced sea ice area.
  49. Dikran Marsupial at 00:13 AM on 18 April 2011
    Video on why record-breaking snow doesn't mean global warming has stopped
    Gilles@21 Firstly, it is steerable, all we have to do to see A1F1 is to carry on doing just what we are doing now. Secondly, for falsifiability, it doesn't have to be steerable (e.g. Eddington's corroboration of Einstein's theory of relativity, neither Einstein nor Eddington control the positions of stars or planets). Thirdly, it doesn't have to be A1F1, if temperatures fall over the next century by say a degree or more below the lower error bar of the most appropriate scenario, that would falsify AGW theory. As the models have been published, you could even in 2100 put the observed forcings into the model and AGW theory would be falsified if the observed rise in temperature was (say) a degree less than the lower error bar. It isn't hard to come up with a falsifiable test, of AGW, simply because it makes a lot of predictions.
  50. Clouds provide negative feedback
    #18 ERRATUM: Where it say "No, it'll clearly sink." it must say "No, it'll clearly float."

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