Claim: Increased carbon dioxide levels in air restrict plants' ability to absorb nutrients

From the University of Gothenburg and the this is why we buy CO2 generators for greenhouses department.

The rapidly rising levels of carbon dioxide in the atmosphere affect plants’ absorption of nitrogen, which is the nutrient that restricts crop growth in most terrestrial ecosystems. Researchers at the University of Gothenburg have now revealed that the concentration of nitrogen in plants’ tissue is lower in air with high levels of carbon dioxide, regardless of whether or not the plants’ growth is stimulated. The study has been published in the journal Global Change Biology.

Researcher Johan Uddling has been working with Swedish and international colleagues to compile data on how raised levels of carbon dioxide impact on plant growth and nitrogen absorption.

Plant quality impaired by increased carbon dioxide levels

The study examines various types of ecosystems, including crops, grasslands and forests, and involves large-scale field experiments conducted in eight countries on four continents.

“The findings of the study are unequivocal. The nitrogen content in the crops is reduced in atmospheres with raised carbon dioxide levels in all three ecosystem types. Furthermore, we can see that this negative effect exists regardless of whether or not the plants’ growth increases, and even if fertiliser is added. This is unexpected and new,” says Johan Uddling, senior lecturer at the Department of Biological and Environmental Sciences at the University of Gothenburg.

Significance of food quality, biodiversity and productivity

When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally. The study also reveals that the strength of the effect varies in different species of grassland, which may impact on the species composition of these ecosystems.

“For all types of ecosystem the results show that high carbon dioxide levels can impede plants’ ability to absorb nitrogen, and that this negative effect is partly why raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems,” says Johan Uddling.

Accepted “truths” do not hold

Reduced nitrogen content in atmospheres with raised carbon dioxide has previously been attributed to a kind of dilutive effect, in which nitrogen absorption fails to keep pace with the increase in plants’ photosynthesis and growth.

“The findings of this study show that this interpretation is simplified and partly incorrect. We are seeing reduced nitrogen content even when growth has not been affected. Moreover, the effect is there in trials with powerful fertiliser, which indicates that it is not down to limited access to nitrogen in the soil. Future studies should look at what is causing the effect, but it appears to be linked to plants’ capacity to absorb nitrogen rather than to changed levels in the soil,” says Johan Uddling.

###

Link to article: http://onlinelibrary.wiley.com/doi/10.1111/gcb.12938/abstract

And a video that suggests this study might very well be off the mark:

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200 thoughts on “Claim: Increased carbon dioxide levels in air restrict plants' ability to absorb nutrients

  1. As I’ve always written, natural laws apply everywhere in the universe except the realm of climate “science”.

    • exactly…..they just discovered that plants grown with CO2 limiting….increase their nitrogen uptake to make up the difference

      • “They” didn’t actually discover anything. The paper is pay-walled, but the supplemental information makes it clear that this is a meta-study, not an original experimental scheme. It’s based on the work of four other studies completed between 2004 and 2011.

      • “This is unexpected and new,” says Johan Uddling, senior lecturer at the Department of Biological and Environmental Sciences at the University of Gothenburg.”

      • +1 DJ Hawkins
        Yes that’s right, and their hypothesis, for that is what this is, is based on a distortion perhaps of this earlier paper, published in the journal of Functional Plant Biology in 2008 : “Why is plant-growth response to elevated CO2 amplified when water is limiting, but reduced when nitrogen is limiting? A growth-optimisation hypothesis”
        by Ross E. McMurtrie et al.
        (Functional Plant Biology 35(6) 521–534
        http://dx.doi.org/10.1071/FP08128
        In the abstract, it is stated :
        “The optimisation is represented in terms of a trade-off between LAI and stomatal conductance, constrained by water supply, and between LAI and leaf [N], constrained by N supply. At elevated CO2 the optimum shifts to reduced stomatal conductance and leaf [N] and enhanced LAI. The model is applied to years with contrasting rainfall and N uptake. The predicted growth response to elevated CO2 is greatest in a dry, high-N year and is reduced in a wet, low-N year. The underlying physiological explanation for this contrast in the effects of water versus nitrogen limitation is that leaf photosynthesis is more sensitive to CO2 concentration ([CO2]) at lower stomatal conductance and is less sensitive to [CO2] at lower leaf [N].”
        1. Note that they are writing here about atmospheric Nitrogen, and not soil borne nitrates. Since the atmosphere generally contains a huge proportion of Nitrogen (about 78%), it is difficult to imagine what circumstances might lead to a “shortage”, It is the case that is there is a higher humidity level however, then the H2O vapour will be expected to displace some of the Nitrogen percentage by volume. That process is not influenced at all by the addition of small amounts of CO2 gas measured in thousandths of a single percentile.
        2. Note also the conclusion arrived at, that “The underlying physiological explanation for this … is that leaf photosynthesis is more sensitive to CO2 concentration at lower stomatal conductance and is less sensitive to CO2 at lower leaf N”. They are not claiming that total leaf area is reduced because of any elevation in CO2, nor is it the case that in wet years additional CO2 had reduced leaf area. What they had stated was that their MODEL predicted that the leaf area would not increase by as much in wet years as opposed to dry years.
        3. It is not suggested that increased CO2 will actually reduce plant growth.
        Call me a cynic, but maybe when, they speak glibly of “CO2 enrichment experiments”, what they really mean is that to read the absolute proofs, of their hypothesis, a reader must stump up 35 bucks for the privilege of a PDF download, or “Rent” it for two days for 6 bucks !!!
        Scientist to rent = Cab for hire
        Sigh.

      • Arthur Ainslie:
        “Note that they are writing here about atmospheric Nitrogen, and not soil borne nitrates. ”
        No they are not. They are speaking about biologically available nitrogen. There are no plants that can use atmospheric nitrogen, though some can access it indirectly by way of symbiotic bateria. That they speak of “High-N years” and “Low N-years” should be proof enough, because there is always 78 % N2 in the atmosphere.

    • It is important to watch the pea under the cup, as Steve McIntyre is fond of saying. It is by now indisputably accepted that more CO2 causes plants to grow faster. That is, increased CO2 causes them to gain more dry mass.
      However, that increased dry mass is presumably mostly cellulose, starches/sugars, and lignin. None of those molecular types have any nitrogen. Even so, that extra growth is still certainly highly useful to the plants (and to the animals that eat them).
      As a PERCENTAGE, nitrogen may make up a smaller fraction under CO2 enhanced growth. This ought not to surprise anyone since plants can only uptake that nitrogen which is actually present, and putting more CO2 in the air does not somehow magically put more NO3 in the ground.
      So, big surprise. Plants are gaining more mass, but since more CO2 does not put more nitrogen in the ground, the total nitrogen mass is not increasing. The problem with that is what, exactly? Sheesh.

      • A paper from the archives of University of Illinois, Champaign soy face experiment program:
        http://www.igb.illinois.edu/soyface/welcome
        Interesting title Published in 2006:
        Rogers A, Gibon Y, Stitt M, Morgan PB, Bernacchi CJ, Ort DR, Long SP. Increased C availability at elevated carbon dioxide concentration improves N assimilation in a legume. Plant Cell And Environment 29 : 1651-1658, doi: 10.1111/j.1365-3040.2006.01549.x
        Well what do you know.

      • Richard,
        You may be assuming a pretty high level of knowledge in the readership here, but for those unfamiliar with plants, legumes are the exception to the rule I suggested above. Legumes are very unusual in that they actually can fix nitrogen. For that plant group, increased vigor due to higher CO2, would indeed be expected to result in higher nitrogen uptake.

      • TY
        the obvious suggestion for those worried about nitrogen deficient cereal grains would be to plant/eat more peas and beans. Or meat.

      • Re: Legumes and all that
        Yes Richard and TY, what you state is right, and I would go further and say that scientists like these are probably not actually horticulturalists, and they assume that the farmers who grow crops, know nothing about the crops they grow.
        Every farmer knows that if you grow cereals and don’t use additional nitrogen fertilizer, then you must rotate your crops, and include a legume (or a clover) which has the Nitrogen fixing nodules. Stubble burning and plowing in after harvest does enrich the soil with particulate carbon matter, which does slowly oxidize during the next growing season creating CO2 gas which rises up from the ground in significant amounts, and does create additional biomass.
        “Field” experiments by scientists who are unaware of these practices will have compromised their hypotheses, because a measurement of atmospheric CO2 at Mauna Loa observatory is irrelevant with respect to what is going on in a farmer’s field. Similarly atmospheric reduced Nitrogen concentrations measured at wherever you like, will have less effect on a field which had in the previous growing season been cropped with clover or legumes.
        I believe it is the case, that in none of those papers referenced, was any consideration given to farming practices at all, though obviously this must have an effect on plant growth and chemical compound content. As such I believe that most, if not all of these papers are seriously compromised, and even perhaps irreconcilable,

  2. But, but, but, “The findings of the study are unequivocal.” After all, greenhouse keepers are not scientists, are they? We must listen to the scientists and read their peer reviewed papers to find out the truth. (/sarc)

  3. It’s become painfully obvious that research into climate has long since not been about attempting to understand the climate and it’s many natural variations (at least by the usual suspects), but it is tailored to find something, anything, no matter how bogus the paper or research is, that specifically refutes any particular skeptical fact. These “papers” tend to come in waves, with large numbers released just prior to any major climate conference to allow the news media and politicians to wave the memes like battle flags in an attempt to shut down any argument or discussion. And sadly they are far too effective, as the constant bleating of the 97% “consensus” shows.

    • “These “papers” tend to come in waves, with large numbers released just prior to any major climate conference to allow the news media and politicians to wave the memes like battle flags in an attempt to shut down any argument or discussion.”
      I totally agree with you! Also the British Bias Corporation save their climate propaganda util we get “extreme” (we never get that in UK) weather, to support their stance.
      I have yet to hear anything good about AGW from the warmunists either, it is all doom and gloom; there MUST be some positives (and I don’t mean feedback either!)

      • In my years in college, we had a CO2 enhancement experiment going on in one of the greenhouses. this was in the early 70’s -anticipating the imminent “Ice Age.” that was to
        descend. This the biggest load of bravo sierra i have ever read…
        Well, in the last few days anyway..

  4. “For all types of ecosystem the results show that high carbon dioxide levels can impede plants’ ability to absorb nitrogen, and that this negative effect is partly why raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems,” says Johan Uddling.
    ——————-
    Except on planet Earth, where NASA satellites have documented a 25% increase in the biosphere.
    On the plus side for governments,, this “study” is fodder for Paris Climat 2015.

    • The wild flowers where I live in the UK are a great deal larger than normal this year.

      • “The wild flowers where I live in the UK are a great deal larger than normal this year'”
        This may be in part due to another aspect of elevated atmospheric CO2: This past very cold winter, caused by “global warming”.*
        This may seem paradoxical, but long, cold Winters often lead to such occurrences as you describe.
        *snark/off

  5. What this really is saying is that Plants that are grown in CO2 poor environments will require more nitrogen fertilizer in their soil to be able to grow and plants that are grown in CO2 rich environments do not require nearly as much Nitrogenized soil AND grow better as a result.
    Plant 101
    Plants will grow OK in a Nitrogen rich and CO2 Poor environment
    Plants will grow OK in a CO2 rich and Nitrogen Poor environment
    Plants will grow best in a CO2 and Nitrogen rich environment

  6. Now there is a reason to say CO2 harms plants…Its even a peer reviewed study, doesnt matter that the paper is crap. Next target softdrinks, need a study showing CO2 in drinks is making people fat…
    In the real world, dont expect sales of CO2 generators for greenhouses to go down..
    FWIW the study likely used levels of 5000 parts or more…

    • “FWIW the study likely used levels of 5000 parts or more…”
      I have many questions about how these trials were set up and maintained, and how uniformity and QC were achieved and verified.
      I am very curious how this FACE (Free Air CO2 Enrichment) process is set up.
      It would seem highly problematic to increase CO2 in a broad outdoor area for an extended length of time.
      And what about CO2 in the soil?
      In an enclosed space, CO2 enrichment will extend into the growing medium.
      It seems doubtful if the same could be achieved outside.
      Enclosed conditions with great care to achieve uniformity, and eliminate all but one variable at a time, in addition to a double blind methodology, would seem to be what is called for in order to reach any scientific conclusions.

      • Sounds too much like real science.
        Plus, we don’t have time to do all those controlled studies, we have a world to save.

      • I too am interested in their method of increasing CO2. Either it’s enclosed, which likely contaminated their experiment by whatever method they used to enclose it, or it is not enclosed, in which case the CO2 levels in the area varied wildly with every gust of wind, which is completely unlike the situation that would exist in reality.

      • I would think that achieving any degree of uniformity as to concentration of CO2 over a wide area for a prolonged period would be, if not somewhere between difficult and impossible, at the very least incredibly expensive.
        Ditto for the continuous monitoring to ensure that the conditions they are trying to achieve are in fact being achieved…and sustained.

  7. The test in the video would have to be repeated with various levels of nitrogen in the soil. In a nitrogen-rich soil, the ability of the plant to absorb nitrogen might not be important, while in a nitrogen-poor soil it might be.

    • The number of variables is immense, as is the possible factors which can confound any conclusions.
      Optimum levels of various nutrients for a given crop will of course vary considerably if other factors are varied.

      • …and agricultural suppliers will provide a fertilizer combination best suited to deal with the changed environment. I think we are now seeing what the dumbing down of the population through education is producing in our universities and colleges.

      • I am a bit surprised that Anthony did not pick up on a couple other points in the abstract:
        “… As the ecosystems were markedly N limited, plants with minimal productivity responses to eCO2 likely acquired less N than ambient CO2-grown counterparts because access was decreased, and not because demand was lower.”
        Translation: these studies took place in already-nitrogen-starved ecosystems.
        “Effects of eCO2 on productivity and N acquisition did not diminish over time, while the typical eCO2-induced decrease in plant N concentration did.”
        While acquisition was not altered over time, the claimed N deficiency DID reduce over time, although plant growth enhancement was sustained.
        I hardly see any reason for alarm here. And… I am also curious as to how they provided a consistent and calibrated concentration of CO2.

      • Please look up items such as the Australian AGFACE [ Agricultural Free Air Carbon dioxide Enrichment ] or FACE experiments which are open air field crop experiments, ie wheat , barley, pulse crops ie peas, beans chickpeas, Lentils etc where CO2 is released on the upwind side of a some many metres diameter ring of CO2 release points and the controlling CO2 measuring sensors.
        These open air field CO2 enrichment experiments using similar ring type field located, open air, sensor controlled CO2 enrichment across the rings are being conducted world wide by a number of country’s Agricultural and horticultural researchers to try and put numbers on yields changes and increases, fertiliser use, and grain and forage qualities and etc under higher global CO2 concentrations.
        Our local Ag crop Research Institute’s FACE experiment results and etc;
        http://www.piccc.org.au/research/project/252
        http://www.regional.org.au/au/asa/2010/climate-change/co2/7128_nortonrm.htm
        The concentration of CO2 is maintained across the ring [s] by the sensors which measure and control both the amounts of CO2 being released and also to ensure that the CO2 is being released from the upwind release points to drift / blow across the growing crops for the duration of their life cycle of some months from sowing to maturity .
        Yields of grains such as wheat are up by very considerable percentages but grain N levels and consequently grain Protein were down.
        Nitrogen fixing pasture legumes will likely have increased fixation of soil Nitrogen as the amount of soil N fixed by pasture legumes is directly proportional to the dry matter production of the legume / nitrogen fixing plant.
        Grain legumes / Pulses ie; peas, beans, chickpeas, lentils and etc first fix soil N during growth and then draw back that soil N during seed set and fill when creating the [ high] protein generally to be found in the pulse crop’s grains.
        What is not said in the paper is the fact that researchers are currently using current commercial field crop varieties for the FACE experiments that have been bred and adapted to our current CO2, Nitrogen, fertilizer, water and temperature and day length criteria.
        The genetic resources and variability of the plant kingdom including the humanity adapted grain, oil seed and pulse crops are immense.
        It will be little more than a normal genetics selecting and crossing program to both find, cross and breed plant varieties that can both benefit substantially more in yield increases from enhanced CO2 and also have protein levels and grain qualities that are quite adequate and match today’s crops in those desirable and essential qualities.
        And with GMO technology advancing rapidly, the modification of the internal genetic characteristics of grain crops without introducing any other foreign genetic material as in some current convential GMO’s will likely be able to compensate for lower N and protein levels in humanity’s main crops but still enjoy the much enhanced yields from the higher atmospheric CO2 of the future IF that higher CO2 does eventuate.
        A proposition that might well be a chimera and a mirage as Nature just does what Nature does and the hell with what [ some of !? ] mankind in his arrogance and hubris believes he is capable of doing to change the whole course of Nature’s progress and inherent aeons old patterns.
        _________________
        When you can convincingly prove to me that you can control a Volcano then come back and we will discuss the controlling of the Earth’s climate.

    • “How can they keep producing this crap?”
      Seems fairly easy. Once you’ve lowered the bar, anything goes and it pays well too.

      • When you start lowering the bar, there is a point when it becomes fun to go … underneath it.
        LIMBO !

    • How can they keep producing this crap?
      Because it continues the Narrative:
      • Global warming never stopped
      • CO2 doesn’t help plants grow
      • We are at war with Eastasia
      • Evil is good
      • Ignorance is strength
      2 + 2 = 5
      &etc.

      • “2 + 2 = 5”
        Humph, and what did George Orwell say about that claim?
        “Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.”
        Well, at the moment WE are still free to say the correct answer “4” but the truth seems no longer to be “political correct” anymore, since even (formerly) respected universities try to teach us “2 + 2 = 5” today.
        I conclude that we are somewhere between freedom and tyranny now, and hope urgently that true and unbiased Science will break free before we reach the second state definitively…

      • With large enough error bars for “2” (or rounding down, say, 2.4628732 to 2), sure 2+2 can equal (or close enough) to 5. It’s dishonest and misleading of course and Marketing Mathematics.

    • Manure add nitrogen to the soil, so it is solving the problem that they claim to have discovered.

  8. I hope the AGW fans see Johan’s comment;
    “…….raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems”
    So, no probs, eh?

  9. Well, I don`t think the farmers will believe this claim – especially greenhouse farms.

  10. “involves large-scale field experiments” Would someone please tell these bozos there ain’t no such thing as a large-scale field experiment. The very essence of experimental design involves the ability to control for all factors so that “all other things” are equal. This is an impossibility in the field, it’s exactly why the people in clinical trials are closely monitored, in some cases with 2-3 contacts per day.
    Assuming you have 4 regions 8 types of soil 10 crops, each with 3 or 4 varieties, nitrogen and CO2 as continuous variables, other plant nutrients, (8 each at 5 levels), variation in temperature rainfall, not to mention the method of cultivation, (e.g., no-til, low-til, etc.) … anyway. And then there’s the sophistication of the agronomist at each site. I’m coming up with 1.44 billion combinations, or cells in a MANOVA, and then there’s the correction for unequal sample sizes.
    Wow, what a crock of …. manure, which is often used to help plants obtain nitrogen

  11. When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally.

    Who cares. Wheat and rice aren’t very good sources of protein anyway. If you want protein, eat something else.

    • “If you want protein, eat something else.”
      You must mean insects? Red meat is taboo, too much water usage, too much methane, too much land use, too much…

    • Commiebob:
      ” If you want protein, eat something else.”
      You mean my all-pasta diet is probably not a high protein diet?!? Dang! I guess I’ll have to throw on a meatball now and then.
      And I suppose I can’t depend on beer for my daily minimum requirement of protein, either. Oh wait! Does the little worm at the bottom of the tequila bottle count as protein? I’m probably good, then.
      /sarc

    • Why assume that protein levels are reduced?
      Why not actually measure the protein levels?
      Shouldn’t be that hard, they have the actual plants, just test them.

      • My suspicion is they did measure protein, and it did not give the results they wanted. So they skipped that.
        Obviously the conclusion would be much more powerful, and powerfully stated, if they measured protein. And after a years long trial, costing Lord only knows how much money, why on Earth not directly measure the parameter they are drawing a conclusion about?

      • The protein content of wheat flour is important for the different products made from it . Millers analyse and grade the incoming flour , usually by NIR spectroscopy.
        An extract from the NABIM website gives appropriate info:
        “Protein
        The amount of protein in wheat determines how flour
        performs. It is also used for a trading specification. The wheat
        protein is quoted at 100% dry matter and most laboratories
        will test it using a near infrared (NIR) spectrometer, calibrated
        against the reference method. In the reference method, a
        ground sample of wheat is burnt at 1000°C and the gases
        produced are analysed for their nitrogen content. The protein is
        the percentage of that nitrogen gas multiplied by 5.7. Millers
        typically look for a 13.0% minimum protein for bread wheat,
        whereas for a biscuit wheat, a typical level is 11.0 – 11.5%.
        In the UK, France and Germany protein levels are normally
        between 10 – 15% whereas levels in North America are
        usually 15.5 – 17.5%.”
        NABIM is the National Association of British and Irish Millers .
        I would imagine that their records over the past 30 years, of increasing global CO2 levels will contain all the information that you need to know about whether this is a problem or not.
        If the protein content is used as a trading spec it has to be accurate or a thousand lawyers will be sharpening their quills.

      • But this study did not claim to measure protein in specific grains, or even specific parts of specific plants.
        It seemed to be referring to the whole plant, across a range of habitats, including many different sorts of plants.
        If it was regarding specific foods, or seeds, or edible portions of commercially important plants, that would be one thing.
        I saw nothing to indicate that was the case.

    • That’s exactly what I thought. If they want to look at plant protein then shouldn’t they be looking a legume?

  12. “Increased carbon dioxide levels in air restrict plants’ ability to absorb nutrients”
    Isn’t this just another way of saying that with higher CO2 levels plants need less nitrogen fertilizer in order to grow?

    • Thus reducing non point source pollution…
      http://www.ncbi.nlm.nih.gov/pubmed/21830824
      Abstract
      Nonpoint source nitrogen (N) pollution is a leading contributor to U.S. water quality impairments. We combined watershed N mass balances and stable isotopes to investigate fate and transport of nonpoint N in forest, agricultural, and urbanized watersheds at the Baltimore Long-Term Ecological Research site. Annual N retention was 55%, 68%, and 82% for agricultural, suburban, and forest watersheds, respectively. Analysis of δ(15)N-NO(3)(-), and δ(18)O-NO(3)(-) indicated wastewater was an important nitrate source in urbanized streams during baseflow. Negative correlations between δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) in urban watersheds indicated mixing between atmospheric deposition and wastewater, and N source contributions changed with storm magnitude (atmospheric sources contributed ∼50% at peak storm N loads). Positive correlations between δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) in watersheds suggested denitrification was removing septic system and agriculturally derived N, but N from belowground leaking sewers was less susceptible to denitrification. N transformations were also observed in a storm drain (no natural drainage network) potentially due to organic carbon inputs. Overall, nonpoint sources such as atmospheric deposition, wastewater, and fertilizer showed different susceptibility to watershed N export. There were large changes in nitrate sources as a function of runoff, and anticipating source changes in response to climate and storms will be critical for managing nonpoint N pollution.

  13. Does the paper say what the optimum level for CO2 is? If less than 180ppm is bad and increasing levels are equally bad then there must be an optimum. I can’t see it in the abstract, but my guess would ne somewhere around the 350ppm mark (it has to be really doesn’t it).

    • Professional greenhouse folks would probably put it somewhere north of 1000 ppm.
      But, as you seem to surmise, that paper would imply that the approximately 400 ppm that we now enjoy is too high.

    • For all trees and most other plants, more is better until about 1300 ppm.
      So our present alleged 400 ppm is much better than 200 ppm, but 600 ppm would be better still, 800 even better still, 1000 better yet and 1200 best of all.

  14. Actual paper is pay-walled. Abstract refers only to Nitrogen concentration, not total plant nitrogen.
    If carbohydrate concentration is increased relative to total plant weight, then of course N concentration will be lowered.
    Do they have an actual mechanism whereby the roots of the plant have diminished capability for nutrient uptake?
    If productivity is increased, then it would seem to be alarmism at it’s finest to grab at some measurements of relative ratios of whatever to claim that there is a problem.
    I can only imagine how different the reported result would be if someone were trying to demonstrate benefit, rather than ignore any beneficial effects and try and find something that advanced the alarmist agenda.
    Besides for this, what exactly is “powerful fertilizer”? Fertilizers do not have power ratings.
    They can be slow release, sustained release, water soluble…
    When one wants to optimize plant growth, one seeks to supply an optimum level of macro and micronutrients. Too much of any one or several nutrients will impede growth.
    The use of the term “powerful fertilizer” is very odd and seems unscientific and not one that an experienced grower or field botanist would use.
    I wonder what the results would be if someone were to analyze the nutrient concentration of various field crops that were grown years ago, and compared these to the same crop grown in the same place today.
    I wonder if anyone has examined the nutrient concentration of separate trees rings on he same tree, in order to compare 300 PPM wood to 350 PPM and 400PPM wood?
    .

    • I agree, the Abstract is not enough to pass any judgment on this paper.
      How nitrogen (protein) was extracted, measured, how was the quantity expressed, how much lower (10% decrease is not enough info and if indeed only 10% how reproducible or important is this?) etc. all missing in the Abstract.
      We don’t even get the CO2 concentrations used.

      • I also do not think nitrogen should be what is measured if they are drawing conclusions about protein. They should measure protein.
        And break it down by tissue type.
        We know that plants in high CO2 air have fewer stomata. They do not need as many.
        They are not measuring what is important to anyone, and drawing conclusions that seem speculative.

      • Menicholas,
        I skimmed over the paper. They didn’t collect any of the original data. Instead they took data from multiple papers which had already been published and analyzed that. Thus they couldn’t use protein data because that wasn’t what was available. Plus, although they extended their conclusions to protein, they were interested trying to measure total nitrogen in order to assess nitrogen uptake, so measuring just protein would have been restricting to what they were trying to measure. For what it’s worth, because so much of a plant’s nitrogen is locked up in protein, there is a really strong correlation between protein content and total nitrogen content. Not that it matters in this case, though, since the conclusions of the paper are pretty flawed because they have no support for their assumption that decreased ability to absorb nitrogen is creating a limitation.

      • “When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels.”
        ——————————————————–
        Is this from a model?

      • You can judge a paper by an abstract. This abstract is very poor, almost as if on purpose so that you don’t really learn anything without paying to read the entire paper.

    • Horsepucky-we all know plants grow better with higher CO2 concentrations.
      The claim about the plants having lower nitrogen is also garbage-that’s not what you would measure,you would measure nitrogen content in the wheat or rice,as that’s where all the nitrogen the rots absorb end up-in the end product.
      Farmers around here-(NE Ohio,and N central Ohio where my hunting property is located)-use anhydrous ammonia to provide nitrogen after the plants reach a certain point-I asked a couple of them.
      When the corn seeds are planted in the no till fields,ammonium nitrate fertilizer in placed in the ground,under the seeds,so the roots can absorb the nitrogen. The ammonium nitrate used when seeds are planted in mixed with a product called Nserve that prevents the ammonium nitrate from breaking down.
      This is the stuff he uses…
      http://www.dowagro.com/en-us/nitrogenstabilizers/
      I asked the farmer next to my hunting property last spring,as he was planting,because I was interested in the attachment to the tractor-it’s similar to a ripper claw on a bulldozer in appearance,but it drops the fertilizer,plants the seed,and covers it back up as it goes down the rows.
      Then he hits the corn with anhydrous ammonia by side dressing the rows when the plants are about a foot tall.
      Info on ammonium nitrate fertilizers-
      http://plantsci.missouri.edu/nutrientmanagement/nitrogen/practices.htm
      It’s the end product that matter-the ear of corn,the grains of rice or wheat,the soybean,etc.
      Measuring the nitrogen in plants that are ready to be harvested will always lead to a low amount in the plant-it’s in the end product of the plant.

  15. In climate religion (we can’t seriously call it climate science any more):
    Their Devil is CO2.
    Their God is… other people’s money.

    • Here is their bumper sticker:
      Follow Me to…
      The Crystal Ball Cathedral
      Church of the Omnipotent Greenhouse in Carbon
      “Believe or be prosecuted.”

  16. Come on people; this one is really easy.
    Increased levels of CO2 cause plants to grow faster. Increased CO2 may not cause nitrogen absorption to increase. So, plants grown in a CO2 rich atmosphere may have a lower nitrogen, and thus protein content.
    But, since the plants are growing faster, the overall impact on the amount of protein produced per unit of time is probably unchanged. The authors’ results do NOT suggest that higher levels of CO2 will reduce our ability to feed the planet (although this is what they are hinting); they only suggest that animals reliant on vegetable protein may need to chew through a little more food to get the protein they need – food which will be more plentiful due to faster plant growth.
    This is a truly ridiculous study and incredible waste of financial and human resources.

    • I would agree Willie, about the waste of financial and human resources. However, for the sake of CAGW propaganda, it is pure gold.

    • Previous research has concluded that it is nitrogen dilution on account of higher overall plant productivity that causes this, like you say, but this research has concluded that higher CO2 somehow inhibits the plant’s ability to uptake nitrogen from the soil.

    • To be accurate, the N concentration is lower, but the overall N content is higher. Studies on both wheat and tapioca.

  17. Is it readily absorbable nitrogen which is impeded as a result of increased growth due to an exhaustion of readily available N in a high CO2 environment ? Or just a case of an experiment in a closed system seeking answers to a foregone conclusion yet again ?
    One has to wonder when such experiments obviously collide with the real world result of the recent increase in global CO2 having produced the exact opposite on a global scale with a greening of the planet.

  18. After a first glance on this i have the impression that co2 makes the plant use the nitrogen more effectivly. Less quality what ever that subjective statement means, are of no importance. More food are bether than no food.

  19. From the linked Abstract: “free-air CO2 enrichment (FACE) experiments in grassland, cropland and forest ecosystems”
    —-
    How are they enriching the free air in grassland, cropland and forest ecosystems? Does anyone have access to this paper to check the methods stated? It seems to me that it would be quite difficult to enrich a random ecosystem in the open air (what I take “free air” to mean) with CO2. Additionally, how does this CO2 enrichment affect the full life cycle of the plants? Do they grow fast and leave more/fewer seeds? Does the grassland die out and have a different plant makeup?
    There are so many questions about this research paper and the data they should have gathered and reported on, it hurts.

    • Done a long time ago with spectacular results:
      http://sealevel.info/ScientificAmerican_1920-11-27_CO2_fertilization.html
      Currently done at Duke University and descriptions with photos available from their site as well as from other sources, just search the web. Obviously much better control than in 1920, but so what. Same results!
      In this current Abstract the authors claim only a 10% decrease in Nitrogen in their high CO2 and we don’t know if this was protein nitrogen. Anyway, a 10% decrease is irrelevant.

      • rd50
        The linked article is quite interesting. They started with 3 greenhouses and then expanded the test to 30,000 sq. meters (approx. 7 acres). The large field test was situated next to a blast-furnace, with “un­der­ground cent­ral pipe and branch pipes en­circ­ling lengthy plots.” They reported increased growth rates of 70-300% depending on crops.
        I haven’t checked the Duke website yet. Thanks for link info.

  20. What does make sense here is that it is known that, when provided higher atmospheric CO2, plants are more efficient in water and nutrient usage. It is wrong to assume that means that nitrogen uptake is being squelched by CO2. Instead, nitrogen uptake from the improved efficiency is simply less in these plants because they need less—no need for more.
    My read is that plants at low CO2 concentrations, have higher nitrogen content because they are stressed by the conditions. Now we are seeing what healthy plants do.

    • Yes, there are fewer stomata needed, and who knows what else, in a CO2 enhances atmosphere.
      I can think of a whole bunch of reasons for what they found, if it is even a real effect.
      Plants in shade grow more stem to reach the light. Plants in high wind produce more lignin for strength.
      But these represent expensive adaptations for the plant over what would be used in the sun and without adverse winds.
      My sense is that this study is about as unscientific as a study can get.
      In other words, a typical CAGW alarmist piece.

  21. The 1st thought I had was why would they try to find negatives for increased plant growth with increased CO2 levels applied – the world knows plants love CO2. Then I realized the entire AGW playbook is negative if it involves CO2.
    I’ve been waiting for the study that claims increased CO2 causes ED. It is becoming ‘more likely’ that this will happen.

  22. “When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally. The study also reveals that the strength of the effect varies in different species of grassland”
    Poorly written, or bad conclusions?
    Did they measure protein content of any plants?
    Of wheat or rice?
    Why does it not simply state “The study found reduced protein levels of wheat and rice grown when carbon dioxide levels are increased”?
    Why do they refer to the future, and use words like “therefore”?
    What does the actual study actually show?
    “The findings of this study show that this interpretation is simplified and partly incorrect. We are seeing reduced nitrogen content even when growth has not been affected.”
    It sounds to me like they contrived a set of circumstances, in which lack of some nutrients in the soil prevented CO2 from enhancing growth because of the least limiting factor principle, and then applied a broad conclusion which involves interpretation and supposition… instead of rely strictly on measurements.

  23. I don’t think the marijuana growers have any problems at all with nitrogen uptake. The stuff really has a nitrogen kick these days… So my friends tell me.

  24. These “scientists” are also making the assumption that all the extra CO2 in the atmosphere was produced by man, which isn’t the case. Also the CO2 concentration in the atmosphere in the past has been 20x higher than it is now. By their logic, plants would not have been able to ingest N2 and therefore not synthesise amino acids and should have died out. The fact that the biodiversity on the planet is so high and that I am typing this would indicate that high concentrations of CO2 are neither harmful to the climate nor directly or indirectly harmful to life of either plants or animals.

  25. Perhaps vegans should pay attention. The rest of us can rest easy with the knowledge that there are lots of creatures that can convert carbohydrates into protein.

  26. Publication as a ‘peer reviewed’ paper in a Journal i s meaningless as far as veracity of the research is concerned. It seems that all that is needed nowadays though is to pass ‘peer review’ and the claim is made that the result is valid. However, science requires repeatability. Therefore, research is only of real interest once it has been replicated by another completely independent team of researchers.
    This is continually glossed over in the rush to get press releases and abstracts out to convince politicians and the gullibles. I doubt very much if this research will be repeatable – but it has already achieved its aim as has the 97% figure.

  27. My corn was planted the last week of April. It is now passing 5 feet tall and greener than ever, despite the bugs that also thrive in the “garden of eden” conditions which Joe Bastardi correctly predicted for the midwest US. El Nino or not, the NOAA has been way off! The beans will also Harvest early this year. Each year we harvested more then expected from past experience, even in the drought and extreme heat of 2013.
    I will look into having some crops analyzed to compare against normal values for protein content. If this claim is really valid, there should be a trend over the last 50 years of decreasing protein content in row crops. A laboratory and models are unnecessary when reality tests your theory just fine. This is just another example of academia lacking common sense.

      • That is right!
        Look, in the first picture, the angle was from slightly above the man’s head, but by the last one, it was from below his eye level. Obvious optical illusion!
        Dang these lying eyes of mine.
        My sexy new neighbor waving that suntan lotion at me from across the yard probably looks like the Sea Hag close up.

      • Mr. Mosher,
        I am wondering what you mean to say?
        Are you of the opinion that the pictures are fake, and/ or the captions not true?
        Many people have observed that a picture can be worth a thousand words. I do not think anybody would say that a picture captures the essence of the scientific method, but a picture like the one above certainly does it illustrate a point very clearly: That plants can and usually do grow much faster under higher CO2 concentrations.
        Now, if one thinks this is not true then that’s one thing, or if the particular picture is fake that’s another thing.
        But certainly this picture tells a story which could be detailed at great length and still not give a person as impactful of an overall presentation as the single picture.
        Besides for that, scientific studies, like courts of law, can and do use many forms of evidence and presentations of evidence, as well as data.
        To make a separate point, if one considers the act of viewing something as letting one’s eyes send a picture to the brain, then the reading of a thermometer can be considered, in a way, as using “pictures”.
        Subject to the same source of error my sarcastic first comment just above…line of site errors.
        I recall from my college days hearing detailed and repeated statements on the subject how important lunes of sire are when reading certain instruments.
        MRI, computerized tomography, radar, interferometry…and a zillion other forms of imaging are critical aspects of a wide range of scientific endeavor!
        Talking! Phht!

      • Dahlquist
        You claimed “many” studies from the 1990s and 2000s support the paper cited in the above essay. When pressed you cited and linked to one paper and it refutes your assertion.
        The paper in your link says

        During the last decade considerable attention has been paid to plant growth and metabolism under elevated CO2. Atmospheric CO2 is rising steadily from preindustrial values of 280 µmol mol^-1 to a current global values of approximately 380 µmol mol^-1 and are projected to increase to approximately550 µmol mol^-1 by the year 2050 (IPCC, 2001). The effects of elevated atmospheric carbon dioxide concentration on plant growth and tissue composition have been studied extensively with C3 species as photosynthesis in these plants is unsaturated at the present atmospheric CO2 concentrations and hence the response to elevated CO2 concentration is usually positive (Drake et al., 1997).

        emphasis addedd: RSC
        Richard

      • Richard
        Read further down the paper. Also, other studies done on various species of plants point out both benign and negative effects… C3 vs. c4, etc. Lot’s of studies.
        It seems that they’re saying the co2 causes some species to grow too fast and they aren’t able to take up nitrogen as effectively because of the growth rate.

      • richard, read through the paper a bit. It is an interesting one and it does echo a number of the points raised elsewhere is thread by commenters. Specifically to the issue of protein and protein concentrations, look at the page numbered 239. (Numerous citations are name-dropped liberally throughout)
        Note here though: the question seems to be less whether it does or not, then whether we care or not. For instance, in the one protocol it noted a 14% loss under a 100% N load. But only a 9% loss under a 50% N load. Which seems rather absurdly backwards. But there’s a reasonable discussion about the nitrogen uptake networks and their regulations that may relate to this. Not stated in relation to protein reduction is plant mass. For if we only reduce proteins 14% under heavy fertilization — and on 9% under moderate fertilization — but have, say, 50% more plant mass, then this seems like an overall win on the nutrition angle.

      • “iii) Effects of eCO2 on productivity and N acquisition did not diminish over time, while the typical eCO2-induced decrease in plant N concentration did…”
        So they seem to be saying that the decrease in nitrogen concentration is a temporary effect.
        Right?
        Then they go on to say:
        “Our results suggest that, at the decennial timescale covered by FACE studies, N limitation of eCO2-induced terrestrial productivity enhancement is associated with negative effects of eCO2 on plant N acquisition rather than with growth dilution of plant N or processes leading to progressive N limitation.”
        Which brings me back to the question of how they can suppose to raise CO2 over a broad area, outside, over long spans of time?

      • richard:

        I quoted from it but you and he have not.

        Am I to understand that this is what you consider a rebuttal of the statements I made? Or is this just color commentary that I should ignore?

      • Jquip
        I DID rebut your silly post by linking to my rebuttal of the similar nonsense to yours from Dahlquist.
        I now refer you to all the posts from Menicholas in this sub thread. You may have a point if you can answer all the points Menicholas makes in critique of the paper which is really under discussion in this thread.
        This sub-thread exists because Dahlquist repeatedly made the untrue assertion that there are “many” other papers which say the same as the paper which is really under discussion in this thread, so I asked him to justify that assertion. His response was to cite only one paper and it REFUTES his assertion.
        You are trying to deflect the discussion onto that paper cited by Dahlquist. But the ONLY pertinent thing said in that paper is its agreement with the paper under discussion; i.e. the paper cited by Dahlquist says

        The effects of elevated atmospheric carbon dioxide concentration on plant growth and tissue composition have been studied extensively with C3 species as photosynthesis in these plants is unsaturated at the present atmospheric CO2 concentrations and hence the response to elevated CO2 concentration is usually positive (Drake et al., 1997).

        Richard

    • Dahlquist
      Sorry, a good try but no coconut.
      You said there are “many” papers “from 1990s and 2000s” that say the same as the paper cited in the above essay. When pressed to substantiate that assertion you cited and linked to ONE paper and it does NOT agree with the above article.
      As I quoted, your link says

      the response to elevated CO2 concentration is usually positive (Drake et al., 1997).

      You have come back with a reply that says in total

      Richard
      Read further down the paper. Also, other studies done on various species of plants point out both benign and negative effects… C3 vs. c4, etc. Lot’s of studies.
      It seems that they’re saying the co2 causes some species to grow too fast and they aren’t able to take up nitrogen as effectively because of the growth rate.

      THAT WILL NOT DO!
      I asked you to justify your assertion about other studies. Repetition is NOT justification.
      And what “it seems” to you “that they’re saying” about “some species” does not alter the fact that they do say “the response to elevated CO2 concentration is usually positive”.
      Richard

      • Richard,
        You quoted the Jain and Pandy paper as pointing out that the “response to elevated CO2 concentration is usually positive.” You should note that this was in the context of photosynthetic output. The paper went on to say (all quotes are from the same paper):
        “As a result of this primary response [referring to the improved carbon assimilation], and a range of secondary responses,including growth, dry matter allocation, and nutrient composition and assimilation,may change”
        “Therefore, factorsthat may affect availability and uptake of N are critical in determining plant and ecosystem responses to high CO2”
        “The overall nitrogen concentration in plants on dry weight basis decreases when they are grown in enhanced CO2 (Jain et al., 2007)”
        “Further, the total amountof nitrogen per plant is often unaltered (Hocking and Meyer, 1991a) or reduced (Conroy et al., 1992) in enhanced CO2”
        .
        I highly recommend that you take the advice of Dahlquist and Jquip and read beyond the first page of the paper.

      • Hmm, this seems to be getting a little tense.
        Maybe while we are on the subject of coconuts, plant growth, and improved/decreasing yields…we should take a small intermission to consider my efforts to raise a crop of coconuts here in Fort Myers.
        If that is not a sufficiently entertaining notion, perhaps we could try this:
        https://youtu.be/Gl97GJvYGdM

      • Jimmy
        I DID “read beyond the first page of the paper” cited by Dahlquist.
        I refer you to my above response (that is here) to the similar twaddle to yours but from Jquip.
        Among other things, I say there

        You are trying to deflect the discussion onto that paper cited by Dahlquist. But the ONLY pertinent thing said in that paper is its agreement with the paper under discussion; i.e. the paper cited by Dahlquist says

        The effects of elevated atmospheric carbon dioxide concentration on plant growth and tissue composition have been studied extensively with C3 species as photosynthesis in these plants is unsaturated at the present atmospheric CO2 concentrations and hence the response to elevated CO2 concentration is usually positive (Drake et al., 1997).

        Strewth! The truth hurts warmunists! And that is demonstrated in this thread by the desperate attempts of trolls to refute the truth that plant growth is increased by elevated atmospheric CO2.
        Richard

      • I suppose it is allowed for posters like Richard s Cortney to creep back into a post late at night when everyone is sleeping and the post has been laid to rest, to continue to manipulate and trash talk people who aren’t there to respond in order to make himself look smart and good…A real TRUTH SEEKING SKEPTIC who cannot stand to hear the truth about a minor, possible aspect of co2 increase. It simply cannot go without an attack on one who brings up a possible problem with co2 in a discussion forum.
        It is not my responsibility to lead Richard by the nose to anything. I gave him what I had and was truthful and respectable with him. Criticizing another for not doing what you yourself are perfectly capable of doing is lazy and childish. Richard had every opportunity to listen to me, jquip and Jimmy and refer to the study which contained references to 30 or more other studies and did state that co2 does have some negative effects on some plant species. He just needed to entertain an open mind and do his own research, rather than bag on me for not doing his work for him.
        After this exchange, I did a search of him and found many people who know him for similar bashing on people. He has a bad reputation for this. I would hope he can learn that bashing people for stating a truth and referring others to some good info is not a reason to insult and harangue that person, as we have similar goals in opposing the CAGW agenda. However, I am not going to go about bashing someone for stating something about the issues with co2 because I simply don’t like to hear it, as Richard seems to have done to me.
        Clean your act up Richard S. Courntey. Please. It would be a favor to all of us who have had to endure tour BS.
        Dahlquist

      • Dahlquist
        I don’t “creep” and my latest posting yesterday was at 8.00 in the evening.
        I suppose it is to be expected that someone will not know the world has different time zones when he is too ignorant to know elevated atmospheric CO2 concentration increases plant growth.
        Dahlquist, you made an untrue claim.
        You repeated your untrue claim.
        I pressed you to substantiate your untrue claim.
        You could not – and you cannot – substantiate your untrue claim.
        Skeptcism consists of demanding that unsupported claims be substantiated.
        You now say

        I suppose it is allowed for posters like Richard s Cortney to creep back into a post late at night when everyone is sleeping and the post has been laid to rest, to continue to manipulate and trash talk people who aren’t there to respond in order to make himself look smart and good…A real TRUTH SEEKING SKEPTIC who cannot stand to hear the truth about a minor, possible aspect of co2 increase. It simply cannot go without an attack on one who brings up a possible problem with co2 in a discussion forum.

        The “truth about a minor, possible aspect of co2 increase” is that YOU LIED and you are whinging because I exposed your lie. There are NOT “many” papers from the “1990s and 2000s” that agree with the paper exposed in the above essay.
        Your claim to know of many such papers was a LIE, and you are upset because I exposed the truth. And that exposure is NOT an “attack”: the only “attack” was by you and was on the truth.

        Take your thumb out of your mouth, dry your eyes, and ask Mummy to give you a cuddle. When you grow up you will learn that some of us will always demand that you justify any fairy tales you promote as being reality.
        Richard

  28. Increased levels of carbon dioxide (CO2) have helped boost green foliage across the world’s arid regions over the past 30 years through a process called CO2 fertilisation, according to CSIRO research.
    http://www.oarval.org/CSIRO-Foliage1982-2010.jpg
    From “Deserts ‘greening’ from rising CO2”. CSIRO, the Commonwealth Scientific and Industrial Research Organisation. Australia’s national science agency. July 3, 2013.
    At http://www.csiro.au/en/Portals/Media/Deserts-greening-from-rising-CO2.aspx
    This page was removed from the CSIRO Website.
    See Deserts ‘greening’ from rising CO2 (Watts Up With That? July 8, 2013)
    http://wattsupwiththat.com/2013/07/08/deserts-greening-from-rising-co2/

  29. Even to a non-scientist like me, this study seems to have obvious flaws all over it.
    My question is, why aren’t the botanists and agro scientists speaking out about this? Surely at some point, scientists in these distantly related (from climate science) disciplines must call BS on studies like this.

    • Katherine009
      Botanists and agro scientists have been talking about this for years. Higher levels of co2 affect many plants ability to take up nitrogen efficiently. The article here is correct.

      • Dahlquist
        Talk is cheep. Research is not.
        Cite previous studies you agree if they exist. Otherwise, please stop making false assertions that waste space in the thread.
        Richard

      • I don’t know of any studies that show that higher CO2 concentrations actually inhibit nitrogen uptake (although many studies claim to show this). But there are numerous studies that show plants grown under higher CO2 concentrations to have lower nitrogen contents and even take up less (so it’s not just a dilution effect). For example:
        http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2486.1998.00101.x/abstract
        http://www.nature.com/nclimate/journal/v4/n6/full/nclimate2183.html

      • Richard
        I only had a few minutes to briefly scan a few studies and there are many on various crops and plants. Many of the articles do state the negative effects of increased co2 on some species. (read further down the one I cited you). Also, search “interactive effects of nitrogen and increased co2 in plant growth”. It’s not all bad Richard, but I’m doing a few things other than blogging here. Apologies.
        D

      • This issue is whether the conclusion is correct…they’re implying that the nutritional content of the plants is lower due to higher CO2.

      • Katherine009
        Thankyou. Well said. As you say

        This issue is whether the conclusion is correct…they’re implying that the nutritional content of the plants is lower due to higher CO2.

        The only responses to your fine posts have been untrue assertions that “many” other papers say the same.
        Richard

  30. The nitrogen content of the air has already decreased from 78.09% to 78.08%; we are all doomed. To Paris!

  31. I struggle, hard, to preserve respect for the established research community and the earnest types who do “climate research” for a living, often with impressive qualifications. I struggle to take seriously their earnest narratives and their sense of eco-morality. But with transparently fraudulent output like this, the struggle becomes almost a hopeless one. This is totally dishonest shite.
    The story “Decreased nitrogen uptake with increasing airborne CO2” could just as well be spun as: “Increased nitrogen uptake as a sign of CO2 starvation stress”.
    You We pays your our money
    You They takes your their choice
    By analogy, oxygen which (last time I checked) was necessary for aerobic respiration and thus essential to life, also kills us by gradually oxidizing our cells and tissues and making them age. So if the political wind required it, even oxygen in the air could be made into a villain.
    Its time we started protesting this by withholding the tax we pay that goes to climate propaganda.

  32. The study is a metastudy of previously reported work. The authors found 35 previous peer-reviewed studies, ranging in time from 1992 to present. Some of these were many years long studies of grasslands and others were one year studies of other ecosystems. Some looked at above ground biomass only, some included root systems. The CO2 enhancement was in the range 200ppm to 300ppm above ambient levels. Some of the studies involved two levels of nitrogen augmentation.
    By combining grassland, cropland and forest results the fitted regression is Y = 1.15 (0.08) X – 10.3(2.0) where the values within brackets represent 95% confidence intervals; r2= 0.68 and n = 242. Where Y=enhancement to nitrogen accumulation (in percent) and X is enhancement to net primary production (in percent). r2 is a goodness of fit measure, and n is the number of independent measurements of which some studies produced far more than one. For example, if the same researchers provided reports on two species of plants, then such accounted for two independent observations.
    Note the following about this relationship:
    First, the slope is greater than one by 15% (plus/minus 8%). What this says in effect is that for enhanced net primary production the accumulation of nitrogen is larger by 15%. By visual inspection I would say that if the relationship were done for croplands alone the effect would be more positive yet as the smaller number of results for grassland and forest have a much smaller slope–possibly even negative.
    Second, The intercept is negative (-10.3%). What this says is that for those experiments in which enhanced CO2 had no positive effect on net primary production, then those plants showed a decline in nitrogen accumulation. Now, someone with more knowledge of plant physiology than I will have to say if this makes sense or not. However, it is this second observation that appears to drive the stated result of the paper, which is to say that enhanced CO2 will lead to a reduction in protein content of foods, because the positive slope says that if enhanced CO2 drives net primary production strongly then net nirogen accumulation eventually become positive.
    Third, I did not see any discussion of the various methods by which nitrogen content is evaluated.

      • No I can read from my office at the university. The study is a lot less than it seems. Read my second point in particular. The relationship is one of “enhanced nitrogen accumulation” as long as there is also some enhanced net primary production. If the enhanced CO2 produces no or little increase in net primary production, then there is some depletion of nitrogen. It is the negative intercept in the relationship that they are drawing all attention towards. It is also a strange finding. It must be that in some plant spcies, or under some circumstances, the enhancement of CO2 triggers a response that reduces available nitrogen–for example the CO2 triggers growth of some fungus or bacterium that nails the nitrogen fixing bacteria or something like that.

    • That is a good summation, Kevin. I will add that when my family was huge in the cattle/dairy business, we placed far more emphasis on total nutrient content than on protein content, because the former yielded better, bigger, healthier cattle and more milk production from the cow herd.
      This study looks like a lot about nothing. Interesting, but still ……

  33. This paper is so pay-walled that even the references are off limits without a fee. Is this science or business?
    The paper claims to undertake ecosystem-scale experiments using FACE (free-air CO2 enrichment). That in itself is an immense undertaking, as each species of plant may respond differently to enhanced CO2 and productivity and composition would need to be measured at each section of the plant –including the roots. They would also need to keep each other variable in each ecosystem controlled in order to call this an experiment.
    In just the forest ecosystem alone it would require the study of hundreds of species, and they purportedly did this on forests, grasslands, and crops (all crops?!). I can’t decide, am I more befuddled by their “surprise” findings or that they managed to fit all of this research into a 14 page paper.
    The claims they make actually go against the conclusions from dozens of previous papers so they will surely face rigorous scrutiny within their own field.
    i) It’s very hard to determine how robust such a huge undertaking that this paper is claiming to be without actually seeing their methodology. But it’s odd that they determine a correlation of r^2 = 0.68 between eCO2 (actual composition not given in the abstract) and nitrogen composition universally among all ecosystems. That’s not what previous research has found.
    ii) They found that decreasing N content was universal regardless of increased plant productivity, again, not what previous research has found.
    iii) “Effects of eCO2 on productivity and N acquisition did not diminish over time, while the typical eCO2-induced decrease in plant N concentration did. Our results suggest that, … N limitation of eCO2-induced terrestrial productivity enhancement is associated with negative effects of eCO2 on plant N acquisition.” It’s actually hard to decipher this. It appears they are making a contradictory statement with this; effects causing decreasing N acquisition doesn’t change over time but the “induced decrease” in plant N concentration does diminish.
    Perhaps they will next publish on WHY all the previous research is wrong and they are right, but I won’t hold my breathe.
    http://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108

    • RW,
      I completely agree with everything you wrote here.
      Very important points about the scope of the undertaking, and trying to control variables.
      “It’s actually hard to decipher this. It appears they are making a contradictory statement with this; effects causing decreasing N acquisition doesn’t change over time but the “induced decrease” in plant N concentration does diminish. ”
      Glad to here someone else say this…I was wondering if it was just me.
      They seem to be saying the effect is temporary. And then a bunch of gobbledygook that is difficult to parse.

  34. As I recall, one of the greatest benefits to enhanced CO2 is the reduction in the need for photorespiration in the plants due to a lesser need to gain sufficient CO2 for carbon fixation and growth. This substantially lowers the metabolic costs of obtaining sufficient CO2 and increases growth substantially. One of the byproducts of photorespiration (PR) is ammonia so a reduction in PR could easily result in a reduction in N production depending on environment, soil, etc. etc. The authors in their laconic abstract (no real facts about how they tortured the plants in their test sites) do imply that all the test sites had low nitrogen-“As the ecosystems were markedly N limited”- which makes their sweeping conclusions rather unsupportable without testing in more N rich conditions. They also note N was reduced in plants at all sights without stating the forms the N was in. Basically, you have nitrate, nitrite, ammonia, ammonium, aminoacids, proteins as well as nitrogen-containing alkaloids, DNA, pyrimidines etc. Any analysis needs to characterize these forms clearly to understand why N is lower and whether this reduction is a detriment or benefit to the plant. What they conclude is unjustified based on their results and indicates a desperate search to validate the negative effects of CO2 while spinning and ignoring the facts to support their position.

    • Exactly Dan.
      This does not appear to be a study of food production, or the nutritional value thereof.
      Just saying plants have less concentration of nitrogen in their tissues does not seem to be a very conclusive point of evidence for a future with less protein in grain crops.
      And if there is more grain produced in total, but each kernel is slightly less protein dense, this could be a net plus in many respects.
      If each kernel has less protein but is equally viable, this would seem a net benefit for the plant.
      Like most organisms that are on the Earth, billions of years of evolution has equipped plants with finely tuned mechanisms for increasing the chances of survival of that plant under varying circumstances.
      I would be interested to see a study of the health of each plant, disease and pest resistance, ability to reproduce, etc.
      Obviously, as conditions change, some organisms will prove more suited and better able to take advantage of new benefits, or more able to survive hardships.
      No matter what the particular condition which is changing.

    • Does this have something to do with the increased efficiency of the Rubisco protein in the leaves?

  35. Reality check
    It is lack of nitrogen, either in amount or timing of supply that limits the synthesis of carbohydrates from CO2 not, as this paper claims, the other way around. See review by Lawlor:
    http://jxb.oxfordjournals.org/content/53/370/773.full
    “Photosynthetic carbon and nitrogen assimilation and N‐supply
    The role of N in agricultural production is intimately connected with photosynthesis. In photosynthesis, the ‘physical energy’ of photons is converted into the ‘chemical energy’ of ATP and reduced metabolic intermediates, primarily NADPH, which are used in the synthesis of carbon and nitrogen assimilates of many different types, particularly carbohydrates and amino acids (Foyer et al., 2001). These ‘fuel’ the synthesis of biochemical components of organs and ultimately provide the structure of the whole plant (Lawlor et al. 2001). The basic mechanisms of assimilate production are considered for they are central to the understanding of crop production.
    The supply of CO2 for C3 photosynthesis is inadequate in the current atmosphere (360 μmol mol−1) and photosynthetic rates and crop growth and yields are increased by c. 30% under UK conditions if this is doubled. ”
    One cannot just analyses the components of the plant under differing eco systems and make the claims made by the authors of this paper. Responses in crop production are often step changes bring one to the next limiting nutrient and unless these steps are explored in detailed multifactorial response trials covering all required nutrients the results are misleading.

  36. This paper is such rubbish…
    If anything, current CO2 levels are still too low:
    http://www.geocraft.com/WVFossils/PageMill_Images/image277.gif
    CO2 is still at the lowest levels since complex life evolved 600 million years ago.
    12.000 years ago at the end of the glaciation period, CO2 levels fell to just 170ppm; just 20ppm away from photosynthesis shutting down and all life on Earth going extinct….
    We should be ecstatic that CO2 levels are recovering to safer levels, and are already enjoying a 20% increase in crop yields from the CO2 rise from 280ppm to 400ppm….
    BTW, why do the “scientists” that wrote this paper think ALLLLL commercial greenhouse operators keep their CO2 levels at 1000+ppm??? Why indeed…

  37. CO2 generators have long been a staple for serious aquarium enthusiasts too. A search will produce DYI, ebay and professional CO2 gear.

  38. I think they are right. But not for their reasons. The most abundant protein on this planet is Rubisco. It is the protein needed by a plant to capture CO2 and convert it into sugar. It is one of the most inefficient enzymes ever, despite millions of years of natural selection. That has to do with the fact that CO2, on a molecular level, resembles O2. So CO2 must compete with O2 for binding and finally, conversion into a new compound. Of course, O2 will not do so it prevents CO2 from binding. Under higher CO2 concentrations, this effect decreases, which allows the plant to produce less Rubisco, and hence, less protein. The plant becomes more efficient at using its assets. Which translates into: the higher the CO2, the happier the plant. Below 200 ppm, Rubisco shuts down and the plant dies. As will most forms of life on this planet. So enjoy your blessings.

    • Your hypothesis is testable by comparing the effects of higher CO2 on C3, C4 and CAM plants. It could well be that differing levels of Rubisco account for any observed variation in N uptake.

    • A great insight. Thank you. That must be why they did not mention any particular protein in their freely available abstract.

      • Exactly, and why they did not study specific crop yields, for example.
        Big dealio if plants have less of something which they require less of if there is more CO2!
        Their conclusion implies that plants are unable to adapt to higher CO2, while the truth is exactly the opposite.
        Plants are highly adaptable, and adapt automatically to varying conditions. The job of a plant is not to store nitrogen in it’s tissues…it is to reproduce successfully and compete more effectively.

  39. From the abstract
    “As the ecosystems were markedly N limited, plants with minimal productivity responses to eCO2 likely acquired less N than ambient CO2-grown counterparts because access was decreased, and not because demand was lower. ”
    First we limit N availability “markedly” (how much limitation?) then we wonder why plants acquire less even if they did have a positive response to eCO2. The demand would not have been lower, it just was not there to absorb so it could not but the plant managed to increase growth anyway. All this says is that plants do not need increased levels of N to keep up with the increased growth possible due to eCO2.
    Or did they expect the plant to absorb additional N due to increased biomass even when it was not available?
    What about doing the study again where N is not restricted and applied as per normal farming practice.

    • I think they are working on that.
      They are caught up a bit now proving that increased C02 makes happy-go-lucky people miserable and depressed and bigger donuts more fattening.

  40. The abstracts notes that the ecosystems studies were N limited and the acquisition of N was down by 10% in C02 enriched systems that resulted in “neutral or modest changes in productivity”. If N is limited and growth was not enhanced, than doesn’t it suffice to say that N content of the plant would be down.?? It also appears that they did not measure for actual protein content?? So how do we really know that limited N uptake created a problem especially if plant growth was enhanced.

  41. Could you please find a more reliable source than Natural News for greenhouse CO2 usage? That is a really scammy and conspiratorial website. Sure they don’t believe that CO2 is destroying the world but they think everything else like vaccines, GMOs, and “chemtrails” (The delusional belief that the government is spraying toxins from jets) are.
    One example of the idiocy. They correctly state that Monsanto is trying to make aluminum tolerant seeds. But then they say that the chem planes are spraying aluminum so only Monsanto’s crops will grow. Well aluminum is the 3rd most abundant element on earth. Maybe there are regions with too much for plants. And the only way you could significantly affect aluminum content in soil is by crashing planes into it. And even then I doubt it would be enough.

  42. Let’s see. We need to get rid of the Medieval Warming Period. Check. We need to get rid of the Pause. Check. We need to get rid of that pesky increase in Antarctic ice. Check. We need to erase the idea that increases in C02 follow temperature. Check. Now, We need to get rid of the idea that plants benefit from C02. Check.
    All done to provide ‘studies’ that refutes Skeptic positions, that can be cited with the illusion of legitimacy.
    Do I really need to point out who are the real ‘Merchants of Doubt’?
    Propaganda 101.

  43. Gluten is a wheat protein. Reducing gluten in the diet is supposedly desirable. CO2 to the rescue once again. CO2 is like Spiderman, whose amazing powers are always denigrated in the press.

  44. The best value for this paper is as a model for manure in a computer model providing nitrogen to rapidly growing plants in enhanced CO2 environments.
    It would be not be surprising to see this paper idiotically used as proof of CO2 being damaging to plants. I wonder if the White House has gotten hold of this paper yet, they like the whole CO2 as pollutant thing.
    Meanwhile, thank goodness these bozos are not responsible for growing our food supply.

  45. Not surprising that this is from Gothenburg U. Here are a few references that debunked this rather ancient hypothesis:
    Mueller, K.E., Hobbie, S.E., Tilman, D. and Reich, P.B. 2013. Effects of plant diversity, N fertilization, and elevated carbon dioxide on grassland soil N cycling in a long-term experiment. Global Change Biology 19: 1249-1261
    Zavaleta, E.S. and Kettley, L.S. 2006. Ecosystem change along a woody invasion chronosequence in a California grassland. Journal of Arid Environments 66: 290-306
    Richter, M., Hartwig, U.A., Frossard, E., Nosberger, J. and Cadisch, G.  2003.  Gross fluxes of nitrogen in grassland soil exposed to elevated atmospheric pCO2 for seven years.  Soil Biology & Biochemistry 35: 1325-1335
    Drissner, D., Blum, H., Tscherko, D. and Kandeler, E. 2007. Nine years of enriched CO2 changes the function and structural diversity of soil microorganisms in a grassland. European Journal of Soil Science 58: 260-269
    Seems the warmistas are not in line with the scientific consensus…..

    • Re soil microorganism’s, my guess is generating a high level of CO and letting it diffuse into the air in a certain area will do nothing to alter soil chemistry in that area, as higher atmospheric CO2 will do. It almost surely is constantly just being diluted and blown away.
      Another flaw in this deeply flawed, IMO, study.
      Hey, just occurred to me…I wonder how much CO2 the cited studies pumped into the air?

      • using ambient CO2, in all cases, as the control the lowest additional was +180ppm, the highest was ambient x 2 (~760ppm total)

  46. They were concerned with plant growth so this paper supplied some fertilizer.
    What’s the problem?

  47. It is a sorry state of affairs that this paper is so heavily pay-walled because if people could actually read the darned thing they would see that the claim is a lot less than it seems. There is no new research involved, and the actual finding is almost misrepresented in the paper. I will try to describe it one more time. In effect they have found a regression equation from a metastudy. The equation suggests that for some species, especially certain species found in grasslands and forests, enhance CO2 does not lead to eenhanced net primary production, and for these species, all that enhanced CO2 really does is reduce nitrogen accumulation. So, as an example, in the sequence of pine trees and Dr. Idso above, the trees obviously have greatly increased NPP–the regression equation would suggest that these also have a greatly enhanced accumulation of nitrogen. Show me a species that does not respond to enhanced CO2 and that is the sort of species this study really describes.

  48. Just a little research I carried out some time ago on this subject:
    It appears that a concentration of about 1,000ppmv would be beneficial to life on earth,
    this being the concentration that Glass House growers prefer.
    http://api.ning.com/files/XAPctmkiwvgEI5fT6iiGjWFvKNX*
    cWuzeO4qmDVbgA_/Greenhouses.CarbonDioxideIn
    Greenhouses.pdf
    Our exhaled breath is about 4500ppmv
    http://www.biotopics.co.uk/humans/inhaledexhaled.html
    Up to 5000ppmv is acceptable for work places.
    (American Conference of Governmental Industrial Hygienists.).
    Up to 3000ppmv is acceptable for residences
    (Canadian exposure guideline for residential buildings)”
    Medical oxygen has between 10,000 ppmv and 20,000 ppmv in it.
    http://www.bocsds.com/uk/sds/medical/10_carbondioxide_oxygen.pdf
    http://www.bocsds.com/uk/sds/medical/10_carbondioxide_oxygen.pdf
    (Look at datasheets under “O”)
    Currently our atmosphere has about 400 ppmv in it.
    Furthermore, some scientists credit the extra CO2 in our atmosphere as the reason for our
    current increased food production.
    http://www.sciencedaily.com/releases/2009/02/090209205202.htm
    In other words, CO2 is plant food. So important is CO2 that at approximately 180 ppmv all
    life on earth would cease.
    Cheers
    Roger
    http://www.rogerfromnewzealand.wordpress.com

  49. “When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally”.
    What they either ignore or unaware of, is that the same can be said for water, or soil moisture content. It is a well known and an established fact that the protein levels of wheat vary inversely to the yield. In years of below average rainfall, yields fall but protein increases. Conversely in years of above average rain, yields will increase whilst protein will fall. At least that is what happens in Australia’s wheat growing country.

  50. Ok, so let’s float this theory, since it ties various observations together:
    When Man evolved, some 250 million years ago, CO2 levels in the atmospere was much higher – 1000 to 2000 ppm. Due to this level of CO2, the plants he evolved to eat had far less protein than today. The lower CO2 levels experienced in the past few thousand years have resulted in much higher protein levels in plants. Man has not yet fully evolved to adjust to these higher levels, particularly wheat protein, better known as gluten. This is the cause of gastrointestinal problems many people suffer. The higher CO2 levels projected in the future will reduce the number of people experiencing gluten sensitivity.
    No where could I get a grant to research this? Oh, nowhere. It could result in a positive attribute for higher CO2 levels. Never mind.

    • “When Man evolved, some 250 million years ago…”
      Ok, this must not be what you meant to say, is it?

  51. ‘Claim: Increased carbon dioxide levels in air restrict plants’ ability to absorb nutrients’
    ____
    given the same soil, same area, the same time to grow: the bigger plant aggregates less minerals, develops less flavones, vitamines, whatever per mass.
    the claim’s just the academic way to say you need more salt, pepper, vinegar – whatever – to like a salad from the bigger plant.
    Regards – Hans

  52. asking – who pays for such paywalled peer reviewed papers.
    Some climate armageddonism does it?
    Hans

  53. don’t let me be misunderstood:
    the studie’s OK for me.
    but we have a problem when science needs ‘public relations’.
    Hans

  54. So this is just drawing conclusions from a bunch of other people’s papers?
    Isaac Asimov wrote about such fallacy in the 1950’s in the original “Foundation” trilogy where one character was attempting to locate Earth by comparing the published works of other people who had attempted to find the planet, instead of actually looking for Earth himself. Being a genuine scientist himself, Asimov must have run into such coattail riding a lot.

  55. “that this negative effect is partly why raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems,” says Johan Uddling”
    Doesn’t this fly in the face of what farmers tell us?

  56. Amongst all the other problems highlighted in the comments about this paper:
    Nitrogen does not exist in the plants as N2, a gas, it is used by the plant to create proteins and nitrates. The NIR analysis determines the total amount of nitrogen in the dry sample, but cannot distinguish between proteins and nitrates. Protein levels are estimated as a percentage of the total Nitrogen in the sample. However we don’t know whether the ratio of proteins to other nitrates in plants grown in high CO2 atmospheres remains the same as for those grown in low CO2 atmospheres. The actual amount of protein could be higher or lower than estimated by NIR analysis.
    As pointed out in comments above, rice, most cereals and plants grown as forage for domestic animals are relatively low in protein.
    High protein in forage plants is not recommended for long term feeding of equines and ruminants, it can cause a number of problems in these species.
    The presence of protein and nitrates in hay and forage is a function of the amount of nitrogen in the soil. An excess of nitrogen fertilizer results in high levels of protein and nitrates in the plants. The high levels of nitrates in hay and forage causes adverse health effects in equines and ruminants, including abortions and still births.
    Furthermore high protein in hay and forage requires the feeding of supplemental Lysine, an essential amino acid in order to avoid dietary imbalance and deficiency.
    The amount of protein reported on feed analyses is reported as a percentage of the sample dry matter. In other words, they dry the sample and test for the amount of various elements, including Crude Protein, Estimated Lysine, Lignin, Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), WSC (Water Sol. Carbs.), ESC (Simple Sugars), Starch, Non Fiber Carb. (NFC) Crude Fat, Ash, Major Minerals (Phosphorus, Magnesium, Potassium, Sodium, Calcium) and Trace Minerals (Zinc, Copper, Manganese, Molybdenum, Selenium, Cobalt).
    Furthermore the amount of protein as a percentage of the dry matter is not the only consideration, the availability of that protein is as important, or more important then the amount present. For instance, in the case of a horse, protein in grass hay is only around 50% available through digestion, whereas protein from whey isolate is almost 100% available. So if you want to increase the protein in feed it is more cost effective and targeted to feed a protein supplement that is 100% available to the organism than feeding larger amounts of forage which can result in providing too much digestible energy to the animal for its level of activity. In other words you feed the animal too much and it gets fat (which has adverse health implications) just because you are trying to supplement protein.
    Also, while the percentage of protein produced by the plant, as a percentage of sample dry matter may be lower, the plant may have produced the same total amount of protein, or more, than it did on the low CO2 regime.
    For example a plant that grew to 1kg under low CO2 and produces 13.3% protein = 133g protein
    The same plant that grew to 1.25kg under high CO2 and produces 11% protein = 137.5g protein
    Also NIR analysis is not as accurate as wet chemistry analysis and can be off by 2 to 5% of the values determined by wet chemistry analysis, but it is a much faster and cheaper analysis.

    • George, what you say about the increase in total protein has been established by the FACE (Free Air Carbon Enrichment) wheat growing trials that have been carried out for a number of years at Horsham, Victoria, Australia. Whilst increased yields have occurred under CO2 fertilisation conditions, and % protein has decreased, the bottom line is that the total protein produced per unit area of soil increases which means more efficient use of the soil providing greater ability to feed the masses.
      However as I mentioned in an earlier post the same effect occurs dependent on the amount of rainfall during the growing season. Years of lower rainfall generally sees lower yields but an increased % protein, whilst generally years of higher rainfall sees higher yields but lower % protein, all other things being equal.

      • Thank you for the comment/info and pointing out yet another problem with the study. This study is just another example of bad science and ignoring well established facts.

  57. Good day, all; I’m just a layman, so there’s plenty of scope to be wrong, but…. When the water that the plants will eventually absorb passes through the atmosphere, it absorbs carbon dioxide. More Carbon dioxide in the atmosphere, more carbon dioxide in the water, less nitrogen can be absorbed before the water reaches saturation. The effect of this reduced nitrogen intake would vary from plant to plant; In some it might be suboptimal, in others not. Seems simple to me, but I’m sure someone will point out the error of my ways,,,,,,

  58. About this research … how many people smell a rat? Come on … plant quality impaired by increased carbon dioxide levels??????? Believe that and you will believe anything.

  59. A plant’s primary protein is one called rubisco. This is your photosynthesis protein.
    In chemistry, a shortage of one reactant can be partly made up for by an increase in another. So in today,s world of severe CO2 deficiency, plants had to have a lot of rubisco to function at all. With reduced hypocapnia (I just googled that to verify spelling–very interesting results in human physiology), plants can relax a bit on the rubisco, which will mean they have more energy for making other substances, which means more micro-nutrients. This probably means better health, less disease and greater longevity in the animal or human who eats the plants.

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