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Comments 88101 to 88150:

88101. LukeW at 08:50 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       This post on CO2 is dreadfully simplistic and naive. In the Australian context of savanna woodlands increased vegetation in terms of trees will decrease not increase fire. Grass is what makes fire carry in the world's vast area of savanna biomes. Most detailed crop physiology modellers will now take CO2 fertilisation into account when simulating crop growth. If there is enough water and nutrients growth will be enhanced. At the levels of CO2 enhancement practically experienced in the field is CO2 really having any impact of yield quality? At a whole landscape scale increased CO2 will improve transpiration efficiency and greater water runoff will result. Climate change will have winners and losers. If North America became warmer and wetter - their wheat yields would be boosted considerably, especially with some CO2 turbo-charging. As for more intense rainfall causing greater loss of soils and nutrients - I wonder - there is this thing called soil conservation - contour banks, minimum tillage or zero tillage. Great advances have been made in these areas over the last 40 years. What could have been mentioned at the other end is that CO2 can increase frost sensitivity (deniers would chip in here and exclaim it will never frost again). Anyway the case for winners and losers needs to be made. At nation state level, land use, biome, and ecological patch level. The article here is far too simplistic.
88102. villabolo at 08:46 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @24 Steve L: "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. SteveL; It's refreshing to have a meaningful and rational question to respond to. No, it's not so much glossing over as it is keeping the post both on a basic level as well as brief (You can see how long it already is). However, to answer your question from a non-scientist's view, let me make some inspired attempts. Even if plants should become more efficient in water usage they are still likely to require more water. Perhaps in lesser proportion compared to other factors but more nonetheless. Likely to be of more importance is the increase in soil evaporation. This would effect agriculture due to the soil being exposed. Also when the temperature gets too hot for the plant's basic metabolism, aquifer fed sprinklers would have to be used to cool them down. Aquifers are getting depleted throughout the world. Metaphorically speaking, there is a spider web pattern of effects when you pull just one thread.
88103. adelady at 08:44 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       "How do you explain that it seems to be *universally* unfavorable, everywhere?" Unfavorable? Only if you've got some vested interest in things being much as they have been for the last 10,000 years or so. Many millions of years ago, lots of little critters in a different atmospheric arrangement produced a gas that was poisonous to the biota of the time. In the end, oxygen wiped out a whole "nature" that had developed relying on little or no oxygen. In its place, we got the beginnings of the atmosphere that suits us and the other plants and animals that survive and thrive around us. Nature. Does. Not. Care. About anything. It's like a computer or the internet. It is just a set of processes and linkages that work regardless of what we would call the content. A computer does not know or care if it is used to create beautiful art or write a vile book or play mindless games or run a payroll or spread a 'virus' destroying the hard work of millions of people. It just follows its own rules. If something happens to damage or destroy some plants or animals, 'nature' does not know or care that its processes may take thousands or millions of years to establish a new set of successful items. Its got all the time in the world. Literally. We are the only ones that care whether our own lives or the lives of our descendants will be comfortable and successful or difficult and miserable. We are the only ones capable of caring whether the same considerations affect people we'll never know and plants or animals we will never see.
88104. Bob Lacatena at 08:42 AM on 18 April 2011
       Clouds provide negative feedback
       21, RW1,

       Where does the difference between "established physics" lie ? This is what I don't understand.

       And this is the crux of your problem. You need to do two things: 1) Present your own model more clearly. You skip steps, make leaps, then get frustrated when other people can't figure out where you get your numbers from. You even claimed that you didn't have a model! 2) You are the outlier. You are the one with the unconventional point of view. The burden is yours to explain your position, but more importantly to study (as the rest of us have) to learn what the mainstream science says. If you can't see the difference between what you put forth, and what everyone else already understands, the burden falls upon you to educate yourself to eliminate that gap. You can't just demand that everyone answer your questions, when you don't demonstrate a clear grasp of the established science, or when you make incorrect statements that clearly are not in line with the established science, and yet even when this is pointed out, you can't see the difference, stomp your feet, and get flustered. You can complain that something is incorrect if you can demonstrate that you understand things, and can yourself clearly explain where your position diverges. You cannot, on the other hand, complain that you don't know why people can't answer your questions, and yet refuse to consider other points of view yourself. You also should not be adopting the tone that you are right, all of main stream climate science is wrong, and so everyone else owes it to you to prove to you that you are mistaken. Like it or not, you are the outlier. If you want to "sell" your position, you need to do that, by convincing other people, not by demanding that they convince you.
       Moderator Response: [muoncounter] RW1 has explained his position in considerable detail on the Lindzen and Choi thread; it is not necessary to start that up again. He is correct in expressing an interest in staying on topic.
88105. Ken Lambert at 08:37 AM on 18 April 2011
       The e-mail 'scandal' travesty in misquoting Trenberth on
       Alec Cowan #130 "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 Knox and Douglas paper was published in Aug10 which showed that 2003-08 data for OHC content was flat or slightly negative (cooling)for the top 700m and *deep ocean* of approx +0.09W/sq.m (Purkey & Johnson). The paper cites five Argo studies for 0-700m OHC by Willis, Loehle, Pielke, Knox & Douglas show **negative** OHC change, while von Schukmann (0-2000m) is the outlier showing +0.77W/sq.m. I note that K&D quoted Willis (a private communication) as a reference in the Aug10 paper. This is pretty recent information. I would like know if the Knox & Douglas paper has been contradicted or its findings overturned by more recent studies. BTW all these numbers quoted in the above papers are 'global'. You can highlight parts of the oceans which are heating or cooling, but what counts about 'global' warming are 'global' numbers.
88106. Albatross at 08:28 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       Villabolo, There is much material out there to satisfy the "concerns" raised by the 'skeptics' regarding the nutritional content being diminished for doubled or trebled CO2 levels. One of my main concerns about this post is that there was not meat in terms of referencing the scientific literature-- but some mistakenly take that to mean that such support is missing in the literature. Ironically enough, the only link that you provide in the body text (at point number 3 in your post) is about diminished nutritional quality in some staples, in this case wheat. I'm certain that the "skeptics" do not even bothering reading these posts, they see the title and launch into obfuscation mode.
88107. Glenn Tamblyn at 08:25 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       Several additional points from things I have read in the past - sorry know references, just memory. Increased CO2 levels can result in reduced numbers of Stomata on leaves - with more CO2 available they don't need as many to supply the same metabolic rate. Paleoclimatologists use stomata counts on fossil leaves as a method of estimating past CO2 levels. Stomata are used for evapotranspiration so this may reduce water loss, but this also provides the plants principle source of cooling, so changed stomata count may impact a plants ability to thermo-regulate - an issue in a hotter and certainly more variable climate. Temperature limits are important to plants. They can do quite well up to some temperature limit then declines markedly - the tree-line on any mountainside is the most obvious example of this. With more CO2 available a plant may be able meet its 'food' needs with less consumption of its resources freeing it up to devote more resources to other functions such as protection from predators through the production of more toxins. I believe increased toxin levels have been reported in Cassava. Might we see increased caffeine levels in coffee & tea? Just because a plant may be able to produce more biomass from increased CO2, that does not automatically mean that this increased biomass will manifest as increased yields of the crops we eat. Our food supply is sourced predominantly from the reproductive parts of the plants. Just because a plant is doing better overall does not mean that it will therefore increase its reproductive activity. A common trait is that plants go into increased reproductive activity, more flowering etc when under stress. If the plant is thriving it might devote more resources into enhancing its own survival rather than reproduction. There could even be a reduction in yield from some plants because of this. Finally the response of a plant species to an environmental change can be two-fold: Adaptation to the changed environment via changes to its metabolism or Migration to remain within its preferred environment. The capacty of plants to adapt to an environmental change depends on whether they have the metabolic pathways and behaviours that allow that change or whether they can evolve new traits as a response. If it doesn't have the pre-existing metabolic/behavioural response availabe, then evolution is its only viable response. Which then raises the question of speed of adaptation. With the rate of CO2 change being nearly unprecedented in Earths history, how fast a plant can adapt to a change may its key survival problem. Annuals such as grains may fare better here than larger long lived species that take years to reach sexual maturity. So evolutionary rates of change could have huge impacts on the species mix of ecosystems, with all sorts of flow on effects. As far as migration is concerned, this again depends on mechanism and speed. Wind blown seeds that can go huge distances allow rapid migration. Seeds from fruit that drop near the parent only permit very slow migration. And just because migration speed may be sufficient to keep pace with climate shifts, that doesn't mean the other aspects of the environment they need will be available, particularly soil characteristics. And finally, plants face a predator that not only predates them for food, but unusually predates them very effectively if they migrate, just because they are migrating. Us. We call them weeds and kill them. So given the range of possible impacts on plants due to CO2 rise and temperature change, from individual plant composition to ecosystem structure, the fact that some plants may reap some benefits from increased CO2 is far more likely to be overwhelmed by the diversity of negative adaptation pressures for ecosystems. And since some of these ecosystems are critically important to us - we call them farm paddocks - CO2 increase is far more likely to be a negative than a positive for our food supply.
88108. Ken Lambert at 08:21 AM on 18 April 2011
       A Flanner in the Works for Snow and Ice
       Tom Curtis #75 You say: "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." That is precisely my point. The annual (or per summer) increase in heat absorbed by your calculation is therefore 0.49E20 Joules/year. This compares with Dr Trenberth's 1E20 Joules/year for Arctic Sea Ice comtribution to the global heat imbalance budget of 145E20 Joules/year (equal to 0.9W/sq.m globally)
88109. johnd at 08:07 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       villabolo at 06:59 AM, strange you didn't notice the other thread as you have 3 separate posts in it. Anyway are you going to address the matters I repeated in this thread in "johnd at 05:17 AM" with connection to your assertions, particularly to quantifying your claims about declining nutritional values of foods grown for human consumption, past present and future.
88110. Alec Cowan at 07:51 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       Strange evolution we have, don't we? The plants are not optimized for a 280ppm level of CO₂ imposed to them during millennia, but for the 395ppm actual one and they have yet more to give as they are expecting the level to reach 500, 600, any advance on 700ppm? just to thrive. Even stranger evolution: all plants will equally thrive, the big ones, the small ones, even in lichens, the photosynthetic partner will increase the pace and the mycobiont will follow singing "heigh-ho! heigh-ho! ..." ... it will be heaven in earth!! Alleluia! The fact is that gene pools in every species contain most everything it's necessary to face changes provided there are not so many things changing at the same time and given enough time. Is that factor being taken into account? Everything is good if CO₂ raises to 1000ppm in 10,000 years? 1,000 years? 100 years? 25 years? How come any underground line brings me home? How does a species to know that it needs to adapt to 800ppm CO₂, 5°C more and dryer conditions, or just adapt to 800ppm CO₂ and move from Baja California to Anchorage? Will it have time enough to move as in previous occasions? Do Tijuana, San Diego, Los Angeles, San Francisco, Portland, Seattle and Vancouver let it move naturally?
88111. Dan Moutal at 07:38 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @ Gilles "CO2 has increased, and agricultural production has increased as well." Yes, but most likely the increase in CO2 is not responsible (again see Liebig's law of the minimum). But more to the point, as was stated in the second paragraph of this post "Too much of a good thing can be a bad thing." The effects on climate by CO2 over the past100 years have been small compared with what we expect for the next 100 years under BAU. Which means that the correlation you are so fond of is not likely to continue. Or to summarize, no amount of CO2 will make the Sahara green.
88112. villabolo at 07:34 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @30 Gilles: ""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." This is off topic so my response is going to dead end with this post. Our agriculture is definitely not"advanced" but destructive. 1. Soil erosion of six feet in what used to be prairie. This is due to soil exposure that monoculture inevitably creates. 2. The quality of food has been going down for decades. It's been tested for nutrient levels for that long. 3. As far as pesticides and herbicides are concerned, they are overused and would not even be need with truly advanced horticulture. Do some research on Permaculture, Gilles. It is self fertilizing like nature. Why deplete oil reserves that should be conserved for plastic production? Permaculture is also, by design, very resistant to pests. It eliminates soil erosion and it provides optimum quality food by restoring and increasing the fertility of our depleted soils. You are operating from the assumption tat this is the best of all possible worlds. It is not and FF is actually contributing to its demise even when you take GW out of the picture.
88113. Nick Palmer at 07:33 AM on 18 April 2011
       David Evans' Understanding of the Climate Goes Cold
       dana1981 at #24 Crikey. I really must learn to stop underestimating the stupidity/sneakiness of the "sceptics". You mean the figure Evans used was him saying that if Australia achieved zero emissions from tomorrow that the equilibrium temperature in 2050 would be 0.015 deg less than it otherwise would have been? In other words he meant it would be a tiny bit less hot, not cooler? That really is twisted rhetoric that looks to me like it was crafted to misdirect the listeners.
88114. Albatross at 07:30 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       I agree with Alec @34, and I'd recommend taking it further, if one if going to post images at SkS two things: 1) They should be cited/sourced and a link to the original report or journal paper should be provided. Context is very important. 2) They should not be rooted by a bizarre site like this as BP's image is.
88115. Alec Cowan at 07:21 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @Berényi Péter #26 I'm saying it again: Add 24 dollars and you'll get Manhattan. Where did you get that figure? "Source: Based on ...."? Can you explain how come from 1860 to 2010 that the content of carbon in soils increased? What kind? Where? (Location, level) How come the value of carbon in soils increased when agriculture by using chemical fertilizers and irrigation has obtained crops in a soil increasingly impoverish in humus so the black rich soil in years back has become nowadays that brownish or yellowish thing. A group of people debated some months ago (in Spanish) about this general subject and information was presented about some 6GTons of Carbon lost from soils just from the Pampas, and some other +2Gtons lost from the Chacos during the last century, just in part of my country -those regions totals some 0.7% of emerging lands-. In vegetation, the lost of mass in the Chacos is enormous and maybe we can estimate it in some 0.4 to 0.6 GT of Carbon (35 million of hectares of 20-25 meters high forests with very old trees has been reduced to grassland, bushland and seasonal agriculture). Again, are the soils becoming increasingly dark by humus or the Carbon is kept in some strange chemical process? Could you explain. Your image is very hard to believe. Some 70GT of increment in Carbon content for some roughly 100 million square kilometers of emerging lands -excluding Antarctica, Greenland, deserts, inland waters, rocky places, and the like- is some 0.7kg per square metre, so a volume of some 2-3-4 litres of humus has been add to every m² of black to reddish soil, dry bald grasslands and under human pavement. How come? Can you elaborate? Can you state the source and why you judged it to be appropriate for this site and for this subject?
88116. villabolo at 07:18 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @30 Gilles: "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." For one who is very much into quantifying things to death, let me ask you, Gilles; what level of CO2 increase can be tolerated by plants until a point is reached that noticeably effects them? It's not likely to be a gradualistic or linear incline. It could be like the proverbial straw that broke the camel's back. Besides, do you know the levels of CO2 that where used in the experiments which gave the dramatic results? They are likely to be much higher than our current C2 levels. Of course, those levels are doing nothing but going up.
88117. villabolo at 07:07 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       @5 Gilles: "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 .." That is why we have Intermediate and Advanced levels, Gilles. As far as experimentation on a global scale, why the Hades would that be needed? We can learn all we need to know from a few experiments and draw general conclusions as to what would happen globally.
88118. villabolo at 06:59 AM on 18 April 2011
       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.
88119. Gilles at 06:55 AM on 18 April 2011
       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 ... ??
88120. villabolo at 06:53 AM on 18 April 2011
       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.
88121. DSL at 06:49 AM on 18 April 2011
       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.
88122. dhogaza at 06:49 AM on 18 April 2011
       More Carbon Dioxide is not necessarily good for plants.
       Vegetation was carbon-free in 1860 ???
88123. 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.
       
       
88124. Gilles at 06:32 AM on 18 April 2011
       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.
88125. Steve L at 06:10 AM on 18 April 2011
       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?
88126. villabolo at 06:05 AM on 18 April 2011
       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.
88127. 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?
88128. les at 05:53 AM on 18 April 2011
       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. :)
88129. Dan Moutal at 05:51 AM on 18 April 2011
       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
88130. FatherTheo at 05:50 AM on 18 April 2011
       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?
88131. Dan Moutal at 05:47 AM on 18 April 2011
       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.
88132. sweikart at 05:36 AM on 18 April 2011
       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.
88133. sweikart at 05:30 AM on 18 April 2011
       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
88134. Albatross at 05:21 AM on 18 April 2011
       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.
88135. 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
88136. johnd at 05:17 AM on 18 April 2011
       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?
88137. johnd at 05:03 AM on 18 April 2011
       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. ???
88138. Gilles at 04:33 AM on 18 April 2011
       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 ?
88139. les at 04:24 AM on 18 April 2011
       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.
88140. 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.
88141. RW1 at 04:04 AM on 18 April 2011
       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.
88142. Liam23 at 03:58 AM on 18 April 2011
       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?
88143. DSL at 03:58 AM on 18 April 2011
       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?
88144. CBDunkerson at 03:55 AM on 18 April 2011
       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.
88145. 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.
88146. 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.
88147. Gilles at 03:29 AM on 18 April 2011
       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 ?
88148. 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.
88149. 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.
88150. 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

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