Memo to Doubters—I was Tempted to say “Deniers”—CO2 is Plant Food!

Guest post by Indur M. Goklany

This illustration from a recent article in Science magazine shows that CO2 is plant food.  It is based on both empirical data and model results (not “data”).  I know that looking at empirical data might seem like a novel idea to some people, but for some perverse reason, I find it more compelling.

image

On the right: Empirical Data. Growth of 21-day-old rice and S. viridis seedlings at different ambient CO2 concentrations ranging from 30 to 800 parts per million. NOTE: The very last set of pots on the extreme right is out of sequence. They are for 390 ppm, while the next to last pots are for 800 ppm.

On the left, Modeled Data:

Modeled changes in CO2 assimilation rate in response to changes in leaf intercellular CO2 partial pressure for C3 and C4 photosynthesis and for a hypothetical C4 rice. Curves 1, 2, and 4 have Rubisco levels typically found in a C4 leaf (10 μmol m−2 catalytic Rubisco sites). Curve 3 shows a typical response for C3 leaves with three times the Rubisco level of C4 leaves. Curve 1 shows the response of a C4 leaf with C4 Rubisco kinetic properties. Curve 2 models how a C4 leaf with C3 Rubisco kinetic properties would respond (a hypothetical C4 rice with C3 Rubisco kinetics). The comparison of these two curves shows the increase in CO2 assimilation rate achieved with C4 compared with C3 Rubisco kinetic properties within a functional C4 mechanism. Arrows to curves 1 and 3 show intercellular CO2 partial pressures typical at current ambient CO2 partial pressures for C4 and C3 photosynthesis. To generate the curves, model equations were taken from (11) and comparative Rubisco kinetic constants from (12). (B) [Reference numbers per source.]

Source: Susanne von Caemmerer, W. Paul Quick, and Robert T. Furbank (2012). The Development of C4 Rice: Current Progress and Future Challenges. Science 336 (6089): 1671-1672.

Finally, note that the top photograph on the right is for rice.  According to Wikipedia, not always a reliable source, but in this case probably trustworthy:

[Rice] is the most important staple food for a large part of the world’s human population, especially in Asia and the West Indies. It is the grain with the second-highest worldwide production, after maize (corn), according to data for 2010.

Since a large portion of maize crops are grown for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one fifth of the calories consumed worldwide by the human species.

In other words, not only is CO2 plant food, CO2 makes human food.  Guess some folks skipped that biology class.

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94 thoughts on “Memo to Doubters—I was Tempted to say “Deniers”—CO2 is Plant Food!

  1. I’m by no means an expert, but doesn’t the question about whether or not it is universally beneficial have something to do with the respiration model used by the plant in question, where not all plants are the same? The argument as I have heard it given is that one kind of plant benefits, but another does not or can even be hurt by it. One species of plant does not a sweeping generalization make either way…

    rgb

  2. the Mark of the Alarmist is the obsession in deleting from history (=”denying”) everything that was known before, even the most uncontroversial stuff like CO2 being “plant food”.

    this is in order to demonize the molecule, so no positive can be described as coming out of it.

  3. I love the Living Histogram! Best data representation ever. Let the plants be their own graph.

  4. Thanks for this article. I had seen C3 and C4 photosynthesis mentioned on this blog before, but never looked into it. According to Wikipedia, C4 plants evolved more recently than C3 (25 to 32 million years ago), have an advantage over C3 plants in arid, hot, and low nitrogen/CO2 conditions, and are common among grasses, e.g. food crops such as maize, sugar cane, millet, and sorghum.

    http://en.wikipedia.org/wiki/C4_carbon_fixation#The_evolution_and_advantages_of_the_C4_pathway

    Wiki predictably links C4 plants to climate change:

    “Increasing the proportion of C4 plants on earth could assist biosequestration of CO2 and represent an important climate change avoidance strategy.”

    Unless the “increased proportion” of C4 plants are long-lived species like trees, however, I don’t see the potential for much more “biosequestration”. Certainly maize and sugar cane grown for fuel ethanol don’t count.

  5. I would like to repeat Alvin’s comment. Is Dr. Brown aware of any plants that are negatively affected by increased CO2? I’m not questioning that there might be some, but I can’t help but think that if there were any, the doomsayer chorus would have let us know about it long ago.

  6. The more CO2, the faster the grass grows, the more CO2 produced by lawnmowers cutting the grass and by humans guiding them. I see nought but doom (;>)

  7. That 800ppm rice looks like a very happy plant indeed! Does anyone know of a study investigating whether such bigger plants also have the same nutritional value per kg? After all, if the ‘twice the size’ plant only has half the nutritional value, the actual ‘gain’ to humanity could be zero. Anyone wanting to throw money at me to do the research can get my email address from WUWT … though it’s only fair to mention that my ‘tender loving care’ has killed chlorophytum (= ‘spider plant’, = grass!)

  8. I have a question. If plants can take that much advantage of higher levels of CO2 (look at 800ppm), is there any implication that there must have been a time in the past where these plants evolved to the point where they could make use of those higher levels of CO2? Or is it that at lower levels, they’d need to be more efficient and the higher levels is just the plant’s reaction to having evolved in lower CO2 environments? Can any assertions be made one way or the other? It seems like some plants take definite advantage of CO2 and that this is the way they evolved. I would think that if they were more efficient at lower CO2 levels, that they would “suffocate” at higher levels (or not the excess at all), but they don’t work that way. At least, not at 800ppm or even 1200ppm. For many plants, 1200ppm seems to be optimal growth. From what I understand, it is common to find 2000ppm inside buildings, though it should be kept below 1000ppm when possible.

    Are there any indications that higher levels were required for plants to evolve to the point where they can take advantage of those levels as seen in the experiment in this article? (And not cause adverse effects to the plants).

  9. The empirical data histogram, if put in the correct order and extended to 1000ppm, might actually look like a hockey stick! That’s my model.

    Why would they not model c3 from the evidence, or use the evidence to challenge their model references? Of course I, Willis and other cynics on WUWT know the answer.

  10. omnologos says:
    June 30, 2012 at 12:49 pm
    the Mark of the Alarmist is the obsession in deleting from history (=”denying”) everything that was known before, even the most uncontroversial stuff like CO2 being “plant food”.
    ==============================================================
    They have also managed to delete from history the experiment performed by an American physicist professor R.W.Wood (1909) demonstrating that no (or no significant) warming is possible by means of “trapped radiation”.

  11. @MrX The only sensible explanation I can come up with is, has to do with the fact that, with higer CO2-concentrations, plants are able to reduce the size of the openings on their leaves, that take in CO2 (at daytime at least) and so lower the loss of H2O. Therefore plants that need the most H2O, or are vulnerable to H2O-loss, might profit more from higher CO2. But i’m not a biologist.

  12. Surely the experiment was done using good, natural CO2. It’s the bad, man-made CO2, no doubt filtered out of the growing chambers built by big oil and coal money, which is destroying the planet.

  13. From davidmhoffer on June 30, 2012 at 1:22 pm:

    The Idso brothers have been studying this for quite some time and have a remarkable database on the matter.

    Brothers?

    The Many Benefits of Atmospheric CO2 Enrichment
    Press Release: 2 Feb 2011

    Snippet: “The book is The Many Benefits of Atmospheric CO2 Enrichment, written by the son/father team of Craig D. and Sherwood B. Idso.”

    We’ll let it slide this time, but if you ever similarly call the Pielke’s “brothers” we’ll be forced to promptly kick you out of the Skeptic’s Clubhouse and tear up your membership card.

  14. Most plant species evolved during times of much higher CO2 concentration. At the historical level of 280 ppm, they were near starvation. ( At about 100 ppm some species die).

    C4 type metabolism is a relatively recent invention and lets plants survive in lowering CO2 levels.

    As a result, C3 plants respond more to increases in CO2 than do C4 plants.

    In general, the increase in yields and growth continues to about 1000 ppm / 2000 ppm range (which is about where it was when the c3 plants were dominant).

    The planet has been sequestering CO2 to excess as carbonates for so long that the plants were on the verge of dying. Their breathing a sigh of relief and getting back to normal (higher) growth rates as CO2 rises is clear evidence of that.

    A forest or a bamboo plot will clear 100% of the CO2 above it in short order if allowed to grow.

    http://chiefio.wordpress.com/2010/10/10/got-wood/

    So world plant growth “limits” on CO2 as the limiting nutrient unless someone puts a lot more into the air or forest fires burn…

  15. I would like to repeat Alvin’s comment. Is Dr. Brown aware of any plants that are negatively affected by increased CO2? I’m not questioning that there might be some, but I can’t help but think that if there were any, the doomsayer chorus would have let us know about it long ago.

    As I said “I’m not an expert…” — I’m a physicist. However, I remember at least one CAGW-believing individual who asserted that there are plants for which excess CO_2 is not beneficial. Then there are secondary problems — the CO_2 might be good, but a side effect of the CO_2 might be worse. That’s the argument concerning CO_2 uptake in the ocean and acidification — the idea that it might push the pH of the ocean out of acceptable bounds. I’m properly skeptical of the argument, but I repeat — one doesn’t need an experiment to show that 800 ppm CO_2 is good for at least some crops. It’s standard practice in many greenhouses to bump it to 1000-1500 ppm (and amusingly, pot growers all seem to take advantage of that to grow their valuable crops faster:-).

    But just as excess water kill cactus, it is by no means implausible that some plants object to excess CO_2. And a single experiment does not prove that the result is generalizable in any venue, let alone one with millions of species in a staggering array of ecologies. I’m a general purpose skeptic, not just skeptical about CAGW…;-)

    Overall, it is probably better to keep our CO_2 level close to “normal” quite aside from what one thinks about CAGW simply because our ignorance can kill us in this as in many things. It isn’t probable, I agree. But wow, sometimes improbable things happen (and sometimes we have the estimates of probability wrong!)

    rgb

  16. Greg House says:
    June 30, 2012 at 1:36 pm

    They have also managed to delete from history the experiment performed by an American physicist professor R.W.Wood (1909) demonstrating that no (or no significant) warming is possible by means of “trapped radiation”.

    Greg, that statement would look just on the surface to go against common sense.

    Of course, you are aware of, and do not deny, the GHG effect by water vapor, a much more plentiful constituent of the atmosphere than CO2 …

    .

  17. Steve C – humans dont often eat the plant itself, we eat the seeds.
    If the increased photosynthesis results just in an increased seed starch content then, if other things were equal, one would expect a proportional dilution of the other consituents ; protein and some minerals.
    However if the increase energy surplus enabled greater root exploration then this might offset a small proportion of this dilution, but overall there will be dilution.
    However ‘starch’ is energy and whilst most of the western world’s problem is overconsumption of such stuff, to those short of food energy is a primary nutrient.
    The increased photosynthesis (or reduced plant respiration) might be expected to increase the nitrogen fixing of legumes – who trade energy for protein with the organisms in their nodules. So increasing the general supply of protein – very important to those short of food.
    So the gain to humanity is very much more than zero, but as you say the increase in supply of some other nutrients might be zero or small.

  18. Most plant species evolved during times of much higher CO2 concentration. At the historical level of 280 ppm, they were near starvation. ( At about 100 ppm some species die).

    One of the many risks of ice age — the low concentration of CO_2 in the last glaciation period was around 180 ppm. That really is getting too close for comfort, because before they die they fail to thrive… it is probably why we evolved plants that are more tolerant of low CO_2.

    rgb

  19. @Chas – (blush) Yeah, actually I’d sussed it was the seeds we actually eat (from every bag of rice I ever bought!) … the important thing here is finding somebody with a stack of spare cash … :-D

  20. No, no. CO2 is what plants breathe in. Articles that continue to express belief in AGW are plant food.

  21. “The U.S. Department of Agriculture (USDA) has determined that a one percent increase in CO2 boosts crop yields by eight percent, translating into a 33-pound-per-acre yield per 1-ppm rise in CO2. The USDA also found that a field of corn in full sunlight consumes all of the CO2 within three feet of the ground. The corn will stop growing unless the surrounding air is stirred constantly by wind currents. In fact, the plants are harmed at CO2 concentrations of 240 ppm, and they die at 160 ppm.” Source: Climate Realists -Kirk Myers

  22. Quite some time ago, Anthony made us aware of a (volcanic) site – “Mammoth Mountain” or “Mammoth Lake” ? – where the CO2 content was killing trees. So there is a limit!

  23. Greg House says (June 30, 2012 at 1:36 pm): ‘They have also managed to delete from history the experiment performed by an American physicist professor R.W.Wood (1909) demonstrating that no (or no significant) warming is possible by means of “trapped radiation”.’

    Er, no. Wood’s experiment only show’s that the so-called “greenhouse effect” is misnamed, which isn’t news. As Wood showed, a common greenhouse raises the interior temperature by preventing convective heat loss. The blocking of IR radiation apparently makes a minimal contribution to heat retention in an actual glass greenhouse. The earth’s atmosphere, with its constant convection, is in a sense the exact opposite of a greenhouse, but we’re stuck with the terminology.

    _Jim says (June 30, 2012 at 2:14 pm): “Greg, that statement would look just on the surface to go against common sense.

    Of course, you are aware of, and do not deny, the GHG effect by water vapor, a much more plentiful constituent of the atmosphere than CO2 …”

    Incoming! [Dons helmet, ducks into foxhole.]

  24. rgbatduke says:
    June 30, 2012 at 2:13 pm
    Overall, it is probably better to keep our CO_2 level close to “normal” quite aside from what one thinks about CAGW simply because our ignorance can kill us in this as in many things.
    ==========================================================
    Beyond the unscientific AGW concept, there is no scientific notion of “normal CO2 level”.

    From the health standpoint the current OSHA PEL (permissible level at the work place) is 5,000 ppm (http://www.cdc.gov/niosh/idlh/124389.html).

    Our ignorance, no, ignorance of our policy makers and machinations of climate scaremongers may cost us our money and our freedom.

  25. _Jim says:
    June 30, 2012 at 2:14 pm
    Of course, you are aware of, and do not deny, the GHG effect by water vapor, a much more plentiful constituent of the atmosphere than CO2 …
    ========================================================
    When you say “GHG effect”, you need to specify which one of at least 3 conflicting narratives you mean.

  26. I did a google search for “CO2 concentration and plant nutrition” and got a slew of negative articles about declining nutrition, for instance, potato protein declined by 14%. Potatoes have 2.1g protein per 100g. Studies show there are small changes in some nutritional content, however, legumes aren’t affected. They never state the CO2 concentration used in the study, only what it was supposed to be at the end of the century. There seems to be a lack of consideration for tradeoffs and they seem to have cherry-picked those plants that could shown to be negatively affected.

  27. MrX
    A large part of the response to increased CO2 is down to a ‘cock up’ in the design of of one a plants main enzymes, which is called ‘Rubisco’ – this enzyme captures CO2 and joins it to make sugars – it has a big defect; it cannot properly distinguish CO2 from O2. This means that a proportion of the time it grabs oxygen and adds it to partly built sugars – effectively ‘burning’ them (which is very pointless) . However the more CO2 there is in the air, the less often this wastefull reaction occurs leading to an improvement in the overall photosynthetic efficiency and output.
    Evolution has worked hard on this problem, but there are trade offs: some Rubisco variants are more CO2 selective but they are slower enzymes ( a smaller, more selective active site doesnt let the CO2 ‘in’ as easily) -There are suggestions that an algal Rubisco exists that is both selective and fast.
    An alternative approach is to capture CO2 chemically by another reaction (sadly this requires energy) and then release it again very close to the Rubisco – this is called the ‘C4′ or ‘CAM’ pathway. Because C4 plants are already ‘pumping’ the CO2 they do not respond as much to increases in outside CO2 levels.
    The adavantage of a C4 system really shows up in dry conditions as you dont need your stomata open so long to take in a given amount of CO2. Or even more cleverly CAM plants like pineapples open their stomata at night – suck in the CO2 and then release it internally during the day :-)

    http://en.wikipedia.org/wiki/RuBisCO

    http://en.wikipedia.org/wiki/Crassulacean_acid_metabolism

  28. Steve C says (June 30, 2012 at 2:30 pm): “@Chas – (blush) Yeah, actually I’d sussed it was the seeds we actually eat”

    Well, when we eat meat (e.g. beef), we’re indirectly eating the whole plant. I did a quick search on alfalfa and found this paper:

    http://www.springerlink.com/content/r042040x33296x85/

    Apparently additional CO2 enhances alfalfa growth, but the effect depends on the “rhizobial strain” associated with the plants. Life is never simple. :-)

  29. Long time since I studied biology, so correct me please. All plants have C4 and C3 cycles. When you see the red leaves of autumn, the C3 cycle is dominant. So it is not unusual. The red pigment takes over as the processing centre for plant energy. Just another adaption under differing circumstances that makes up our world of variation.

  30. Gary Hladik says:
    June 30, 2012 at 2:45 pm
    Er, no. Wood’s experiment only show’s that the so-called “greenhouse effect” is misnamed, which isn’t news. As Wood showed, a common greenhouse raises the interior temperature by preventing convective heat loss. The blocking of IR radiation apparently makes a minimal contribution to heat retention in an actual glass greenhouse. The earth’s atmosphere, with its constant convection, is in a sense the exact opposite of a greenhouse, but we’re stuck with the terminology.
    ===========================================================
    No, it was not just a misnomer, it was a misconception of the “grounding fathers” of the AGW concept. And Wood did not need to show that in an enclosed space convective heat loss is prevented, I guess everyone new that.

    He demonstrated that AGW concept won’t work, because “trapped radiation” produced nothing or next to nothing. Conduction and convection work, of course, but not “trapped radiation”.

  31. Plants are carbon, can’t imagine any plant that is made of carbon that would be harmed by C02.

    Nice place to put Feynman

    The relevant point starts about 2:14

  32. There is no doubt that Co2 is a plant food. How much is too much for which plants? Even here we may have to go past 1,000 ppm or more for most plants and we are currently not even half way there. Tip: the Earth has had 10x more co2 in the pas than today.

  33. Let’s look at this the other way.

    Are there any plants that can survive without C02?

  34. gofer:

    IIRC that study also limited the amount of nutrients actually available. DOH !!

    If a plant is growing faster because it is making better use of the available water, then it also needs more trace nuitrients.
    The way I understand it is that below about 280ppm, the stomate are packed tight, and every time they are opened to breath in CO2, they also let water vapour out. (try breathing at the top of a high mountain. poor plants have been really struggling for a long time)
    As the atmospheric CO2 increases, the plants need less stomate density (its actually been measured, iirc) and so they loose less water through transpiration, and become more efficient.

    There are many things that limit plant grow, lack of CO2 and H2O are primary ones since they are the building blocks, but other nutrients also play a big role, for example, you need nitrogen to make protein and many plants need to get it from the soil.

    If you study predator prey relationships, you can see that the Earth’s CO2 content has been very low for a long time. This indicates that it was a limiting factor on plant growth, We are now , fortunately releasing some of the long buried carbon.. and JUST AT THE RIGHT TIME TO SUSTAIN THE FOOD SUPPLY (so long as we don’t waste it on bio-fuels) Isn’t it VERY FORTUITOUS that we find coal and the released CO2 gives the plants a growth spurt just as the human population expands…… maybe someone planned it that way.(there you go, religious and creationists, think about that one ;-). so maybe we better get out of the way and let it happen.

  35. Good article.

    To add a bit more, take the example of what are perhaps the top half-dozen agricultural crops:

    Wheat, rice, soybeans, and potatoes are C3. Corn and sugarcane are C4. Each benefits at higher CO2, as can be seen at http://www.co2science.org/data/plant_growth/dry/dry_subject.php

    As an illustration, let’s compare wheat (C3) with corn (C4):

    Wheat has much extra growth, around a 49.6% increase in biomass, for a 600 ppm increase of CO2.

    Meanwhile, corn for the same CO2 increase has a 33% increase.

    The C3 plant (wheat) had a bit more benefit than the C4 plant but both greatly benefited.

    There is also a major water usage efficiency benefit, due to plants adjusting their stomatal conductance when they don’t need as much air flow (more CO2 per unit of air) and thus can reduce water losses. Here’s a graph for corn and soybeans, where again both greatly benefited even though the C3 plant had a still greater percentage rise:

    This is unsurprising, as CO2 earlier in geological history was thousands of ppm, a nutrient for lush abundant vegetation (that which became today’s fossil fuels, aside from the abiotic hypothesis which is a mostly unrelated topic).

    Combine this with how global warming is more arctic warming than elsewhere. Primary productivity has risen as observed by satellites:

    Global terrestrial net primary production increased by 6% from 1982 to 1999 ( http://dx.doi.org/10.1126%2Fscience.1082750 ), then was reportedly stagnant (fluctuating down by 1%) from 2000 to 2009. The 2000 to 2009 period was actually a time of slight global cooling, after the high point at the end of the 1990s, as can be seen from the following, so the preceding is not surprising:

    http://www.woodfortrees.org/plot/rss/from:2000/to:2009/plot/rss/from:2000/to:2009/trend

    Over a lengthier time period, an ORNL study estimated that carbon in global terrestrial vegetation increased from approximately 740 billion tons in 1910 to 780 billion tons in 1990.

    http://cdiac.esd.ornl.gov/pns/doers/doer34/doer34.htm

    Nitrogen in soil is remarked upon at http://www.co2science.org/articles/V15/N26/EDIT.php although, besides, we use artificial fertilizer in modern agriculture to keep it not a limiting nutrient.

    For a large amount of discussion, there is http://nipccreport.org/reports/2009/pdf/Chapter%207.pdf which is chapter 7 of the NIPCC report at http://nipccreport.org/reports/2009/2009report.html

    Plus, one can copy and paste part of the title of any of countless papers referenced there, to google such and find the corresponding paper online.

  36. gofer says:
    June 30, 2012 at 3:00 pm
    I did a google search for “CO2 concentration and plant nutrition” and got a slew of negative articles about declining nutrition, for instance, potato protein declined by 14%. Potatoes have 2.1g protein per 100g. Studies show there are small changes in some nutritional content, however, legumes aren’t affected. They never state the CO2 concentration used in the study, only what it was supposed to be at the end of the century. There seems to be a lack of consideration for tradeoffs and they seem to have cherry-picked those plants that could shown to be negatively affected.

    They do a dishonest presentation. You only get that result if you don’t apply enough additional nitrogen fertilizer per unit area to properly fit the increased biomass. For propaganda purposes, making the crop nitrogen deficient is the goal, but it is avoidable. You use a comparable amount of nitrogen fertilizer to now per unit mass of potatoes produced. You just apply more per unit area; for a particular level of production, your total farm area needed goes down. In transparent bias, they are careful not to mention, for example, the 30% yield increase of potatoes at a 300 ppm CO2 increase, like having 130g of potatoes instead of 100g ( http://www.co2science.org/data/plant_growth/dry/s/solanumt.php ).

  37. Frank Kotler says:
    June 30, 2012 at 2:44 pm

    “The high CO2 concentrations in the soil on Mammoth Mountain are killing trees by denying their roots O2 and by interfering with nutrient uptake.”

    http://pubs.usgs.gov/fs/fs172-96/

    It isn’t CO2 in the atmosphere that is killing trees. It is in the soil and affecting the roots. Same thing that happens when a residential gas line springs a pinhole leak.

  38. Regarding my prior post, I forgot to mention more than nitrogen alone fertilizer, but anything from phosphorus to sulfur is the same idea, just adding if needed and not deliberately failing to adjust for greater yields.

  39. I know plants utilise co2 during photosynthesis. This results in the production of carbohydrates and proteins which the plant uses in various ways to complete its’ growth cycle. Any enrichment needs to be balanced against the plants other nutritional requirements, but I’m pretty sure ecosystems will thrive and Net Primary Production will increase. There will be winners and losers as always but green stuff will flourish.
    One thing that will also result from enrichment is the production of more aerosol, the IPCCs’ biggest area of uncertainty = aerosols and their forcing in the settled science!
    If arid areas are stabilised, to some extent, there will be less dust aerosol production , and on the other side there will be more biological aerosol particles produced from more vibrant plant growth.

    http://pielkeclimatesci.wordpress.com/2012/02/29/biological-aersol-particles-are-a-larger-climate-forcing-than-considered-by-the-ipcc/

    Biological Aerosol Particles Are A Larger Climate Forcing Than Considered By The IPCC – A New Paper “Primary Biological Aerosol Particles In The Atmosphere: A Review” By Després Et al 2012

    The thing is I don’t think they have the dust forcing sign correct because they estimate too much clay aerosol=cooling and not enough dark silt aerosol=warming.

    http://sitemaker.umich.edu/jasperkok/files/kok2011_pnas_scalingtheorydustpsd.pdf

    “On a global scale, the dust cycle in most GCMs is tuned to match radiative measurements, such that the overestimation of the radiative cooling of a given quantity of emitted dust has likely caused GCMs to underestimate the global dust emission rate. This implies that the deposition flux of dust and its fertilizing effects on ecosystems may be substantially larger than thought.”

    So you have dust that may be warming more and fertilising more and plants producing rain forming aerosols from BVOCs which all assist stabilisation and enhance ecosystem productivity. Maybe its’ all a bit Gaia! One thing’s for sure Aerosols have a big say in how the climate changes.

    And then you have the atmosphere cleaning itself! Good old Hydroxyl radicals!
    Atmosphere cleans itself more efficiently than previously thought

    http://www.mpg.de/990456/Pressrelease20110113?filter_order=TL&research_topic=UK-CH

    These findings refute the view held by other scientists who believed that the atmosphere is very sensitive to air pollutants (Science, January 7, 2011).

  40. I have heard people talk about negative effects. But they seem to be only able to manage it by adopting bizarre viewpoints.

    One approach is to argue that while all plants seem to respond positively to increased CO2 levels there might be some that respond more positively than others. If you can find a “weed” that responds more positively than an associated “crop” you can try to argue that increasing CO2 levels will cause greater problems with weed control.

    Another approach is to look at the make up of the plant. A plant which is growing very vigorously is likely to have a higher sugar and starch content. You can flip this around and claim instead that the concentrations of other things – vitamins – minerals – are less. This may be true in some cases primarily because the dilution effect of having more sugar and starch.

    These kinds of arguments are so bizarrely contrived that you can’t help but wonder at the motivations of those who make them.

  41. Operators of commercial greenhouses growing all sorts of vegetables and fruits regularly run CO2 atmospheres with much higher concentrations than the outside air has. They do not do this as an experiment but because they know it makes the plants grow faster and bigger. The upper limit of concentration is encountered when workers entering the greenhouse suffer loss of consciousness and death. This is known to be a very bad look for the Company.

  42. C3 plants – wheat, rice, barley, potatoes, most broad-leafed plants.

    C4 plants – corn, sugar cane, ordinary grasses, bamboo.

    The C4 plants don’t need high CO2 levels to grow well and can survive low CO2 levels when there is less precipitation.

    C3 plants grow much better as CO2 levels go higher and higher but when CO2 levels are low, they need to have significant precipitation in order to survive – hence the ice ages were mainly a C4 world with C3 plants primarily relegated to very high rainfall areas, which would currently be tropical rainforest areas today.


  43. _Jim says:
    June 30, 2012 at 2:06 pm

    Can anybody here hand-deliver a copy of this report to the head of the EPA (Lisa Jackson)?

    Nice idea but do you really think it would do any good? After all you can bring water to a jenny [a female ass] but you can’t make her drink.

  44. The negative effects some commentators mention works like this: example, you have twice as much food but only 1.92 times as much nutrition. I really don’t see this as a problem, or a real negative.

  45. “Quite some time ago, Anthony made us aware of a (volcanic) site – “Mammoth Mountain” or “Mammoth Lake” ? – where the CO2 content was killing trees. So there is a limit!”
    I suspect that was CO, aka Carbon Monoxide.

  46. dp says:
    June 30, 2012 at 3:54 pm

    Frank Kotler says:
    June 30, 2012 at 2:44 pm

    “The high CO2 concentrations in the soil on Mammoth Mountain are killing trees by denying their roots O2 and by interfering with nutrient uptake.”

    http://pubs.usgs.gov/fs/fs172-96/

    ———————————————————

    Yeah, that’s the one. Thanks! I wasn’t implying that we are at any risk of doing this by burning fossil fuels – only that too much of a Good Thing can be a Bad Thing.

    We had that gal, “Alice Alarmist” (not her name) who wanted to put Anthony in a room full of CO2… or CO… or one of those, you know… gasses. I’m not sure she understood the difference!

    I have inhaled CO2 off the top of a beer-brewing crock. Quite trippy! I don’t know if you’d consider this a positive or a negative…

  47. Reply to Robert Brown
    Every plant so far studied has improved growth with additional CO2. Go to CO2 Science – they have hundreds of examples.
    Removing CO2 from the atmosphere will limit photosythesis. We need more CO2 not less!
    Jim Petrie

  48. rgbatduke says:

    June 30, 2012 at 2:14 pm

    Most plant species evolved during times of much higher CO2 concentration. At the historical level of 280 ppm, they were near starvation. ( At about 100 ppm some species die).

    One of the many risks of ice age — the low concentration of CO_2 in the last glaciation period was around 180 ppm. That really is getting too close for comfort, because before they die they fail to thrive… it is probably why we evolved plants that are more tolerant of low CO_2.

    rgb
    =======================
    The plants DNA is ready to respond to almost anything that can be thrown at it, as a survival strategy. So far so good.

  49. I wonder what the effects of various concentrations of CO2 on human health are – everything else held constant. Like the Laffer Curve, somewhere between 0 ppm and 10^6 ppm there should be an optimal range for the majority of humans. Determining that would be quite difficult – not to mention the ethics involved.

  50. Greg House says (June 30, 2012 at 3:11 pm): “And Wood did not need to show that in an enclosed space convective heat loss is prevented, I guess everyone new that.”

    Well, no again. Wood wrote in his “Note on the Theory of the Greenhouse”:

    “There appears to be a widespread belief that the comparatively high temperature produced within a closed space covered with glass, and exposed to solar radiation, results from a transformation of wave-length, that is, that the heat waves from the sun, which are able to penetrate the glass, fall upon the walls of the enclosure and raise its temperature: the heat energy is re-emitted by the walls in the form of much longer waves, which are unable to penetrate the glass, the greenhouse acting as a radiation trap.”

    So Wood himself didn’t think that “everyone knew that”, which was why he did the experiment. BTW, when I pointed this out on another board some years ago, one poster still insisted greenhouses depend primarily on the so-called “greenhouse effect”. The claim was even made here on WUWT: “The way an actual greenhouse works is by trapping infrared radiation.”

    http://wattsupwiththat.com/climate-fail-files/gore-and-bill-nye-fail-at-doing-a-simple-co2-experiment/

    So not everyone knew then, or knows now.

    “He demonstrated that AGW concept won’t work, because “trapped radiation” produced nothing or next to nothing. Conduction and convection work, of course, but not ‘trapped radiation.’

    It’s a long way from a greenhouse simulator to the real atmosphere. As Wood wrote, “I do not pretend to have gone very deeply into the matter…” BTW, people have repeated the Wood experiment, with variations. Nahle essentially confirms Wood

    http://www.biocab.org/Wood_Experiment_Repeated.html

    while Pratt does not:

    http://boole.stanford.edu/WoodExpt/

    That’s why I recommend doing Roy Spencer’s “Yes, Virginia” experiment. It’s a well-controlled and much less complex system than a real greenhouse or even a greenhouse simulator.

  51. Frank, do some research on the mediacl affects fo CO2..
    It is quite likely that what you sniffed off the top the brew contain a lot of other stuff apart from CO2.
    CO2 in the air ONLY becomes an issue to humans when it starts to interupt oxygen transfer in the lungs. This is somewhere in the region of 10,000 ppm (iirc) ie 25 time the current atmospheric level.. It is NOT the CO2 that causes issues, it is the lack of oxygen transfer. Many other substances can also affect this oxygen transfer. eg smoke !

    Too much of anything will kill you !!

  52. The really informative part of the picture of C3 plants is not what happened in the right of the photo but what happened to the plants in the left part of the picture. Dead plants and stunted growth.

  53. >>
    rgbatduke says:
    June 30, 2012 at 2:14 pm

    . . . it is probably why we evolved plants that are more tolerant of low CO_2.
    <<

    I wasn’t aware that “we” had anything to do with C4 evolution.

    Jim

  54. Gary Hladik says:
    June 30, 2012 at 6:37 pm

    Greg House says (June 30, 2012 at 3:11 pm): “And Wood did not need to show that in an enclosed space convective heat loss is prevented, I guess everyone new that.

    Well, no again. Wood wrote in his “Note on the Theory of the Greenhouse”:
    “There appears to be a widespread belief that the comparatively high temperature produced within a closed space covered with glass, and exposed to solar radiation, results from a transformation of wave-length, that is, that the heat waves from the sun, which are able to penetrate the glass, fall upon the walls of the enclosure and raise its temperature: the heat energy is re-emitted by the walls in the form of much longer waves, which are unable to penetrate the glass, the greenhouse acting as a radiation trap.”
    So Wood himself didn’t think that “everyone knew that”, which was why he did the experiment.
    =====================================================
    You quote you are referring to contradicts your “Well, no again”. Wood’s intention was to demonstrate, that the “a widespread belief” about “trapped radiation” is wrong. And, of course, everyone knows what happens if one opens the window in winter. If you difficulties to understand that, then ask yourself: did he compared a closed box to an open box? (No, he did not.)

  55. _Jim says:
    June 30, 2012 at 2:06 pm
    Can anybody here hand-deliver a copy of this report to the head of the EPA (Lisa Jackson)?
    .———————–
    Not Lisa Jackson……..Mitt Romney!

  56. Gary Hladik says:
    June 30, 2012 at 6:37 pm
    It’s a long way from a greenhouse simulator to the real atmosphere. As Wood wrote, “I do not pretend to have gone very deeply into the matter…” BTW, people have repeated the Wood experiment, with variations. Nahle essentially confirms Wood http://www.biocab.org/Wood_Experiment_Repeated.html while Pratt does not: http://boole.stanford.edu/WoodExpt/
    That’s why I recommend doing Roy Spencer’s “Yes, Virginia” experiment. It’s a well-controlled and much less complex system than a real greenhouse or even a greenhouse simulator.
    ========================================================
    First, selective quoting is not nice. Wood did not write just “I do not pretend to have gone very deeply into the matter…”, but he stated in a polite way: “…and publish this note merely to draw attention to the fact that trapped radiation appears to play but a very small part in the actual cases with which we are familiar.” And after that the AGW concept was dead and people were not taught the “greenhouse effect” at schools.

    Second, the Wood’s opponents including Nobel laureate Arrhenius did not come up with another experiment to debunk the results of the Wood’s one. How Pratt got different results remains a mystery.

    To the “Roy Spencer’s “Yes, Virginia” experiment”, is it possible that you forgot that it was not an experiment, it was a so called “thought experiment”?

    And last but not least, Al Gore would have not presented his fake experiment (http://wattsupwiththat.com/climate-fail-files/gore-and-bill-nye-fail-at-doing-a-simple-co2-experiment/) if he had had a chance to debunk Wood by a genuine one.

  57. _Jim says:
    June 30, 2012 at 2:06 pm
    “Can anybody here hand-deliver a copy of this report to the head of the EPA (Lisa Jackson)?”

    You mean this Lisa Jackson that says “…..greenhouse gases are pollution”?

  58. Greg House says (June 30, 2012 at 7:50 pm): “Wood’s intention was to demonstrate, that the ‘a widespread belief’ about “trapped radiation” is wrong.”

    You left out the part about “within a closed space covered with glass, and exposed to solar radiation”, you know, like in a greenhouse. I think I’m beginning to understand the origin of the “greghouse effect”. :-)

    “If you difficulties to understand that, then ask yourself: did he compared a closed box to an open box? (No, he did not.)”

    Well, no yet again. To demonstrate the small effect of “trapped radiation” relative to “trapped air”, it’s essential to trap the air, you know, like in a controlled experiment. The ambient air temp (the “open box”) is the control for convection, and the salt window is the control for radiation. In the experiment, trapped radiation had a minor effect compared to the major effect of trapped air in both boxes. QED for greenhouses, not for the atmosphere. :-)

    Incidentally, the Nahle experiment I referenced above uses an actual box with holes as his “open box” control.

  59. Written in 2009 – some good answers above to some of my questions, thanks.

    http://wattsupwiththat.com/2009/01/30/co2-temperatures-and-ice-ages/#comment-79426

    (Plant) Food for Thought (apologies – written too late at night)

    Background:

    http://www.planetnatural.com/site/xdpy/kb/implementing-co2.html

    1. “As CO2 is a critical component of growth, plants in environments with inadequate CO2 levels – below 200 ppm – will cease to grow or produce.”

    http://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth's_atmosphere

    2. “The longest ice core record comes from East Antarctica, where ice has been sampled to an age of 800 kyr BP (Before Present). During this time, the atmospheric carbon dioxide concentration has varied by volume between 180 – 210 ppm during ice ages, increasing to 280 – 300 ppm during warmer interglacials…
    … On longer timescales, various proxy measurements have been used to attempt to determine atmospheric carbon dioxide levels millions of years in the past. These include boron and carbon isotope ratios in certain types of marine sediments, and the number of stomata observed on fossil plant leaves. While these measurements give much less precise estimates of carbon dioxide concentration than ice cores, there is evidence for very high CO2 volume concentrations between 200 and 150 myr BP of over 3,000 ppm and between 600 and 400 myr BP of over 6,000 ppm.”

    Questions and meanderings:

    According to para.1 above:

    During Ice ages, does almost all plant life die out as a result of some combination of lower temperatures and CO2 levels that fell below 200ppm (para. 2 above)? If not, why not?

    Does this (possible) loss of plant life have anything to do with rebounding of atmospheric CO2 levels as the world exits the Ice Age (in combination with other factors such as ocean exsolution)? Could this contribute to the observed asymmetry?

    When all life on Earth comes to an end, will it be because CO2 permanently falls below 200ppm as it is permanently sequestered in carbonate rocks, hydrocarbons, coals, etc.?

    Since life on Earth is likely to end due to a lack of CO2, should we be paying energy companies to burn fossil fuels to increase atmospheric CO2, instead of fining them due to the false belief that they cause global warming?

    Could T.S. Eliot have been thinking about CO2 starvation when he wrote:
    “This is the way the world ends
    Not with a bang but a whimper.”

    Regards, Allan :-)

    P.S.
    A possible explanation is that ice core CO2 is directionally correct but low in absolute terms due to CO2 diffusion.
    Leaf stomata data shows much higher CO2 values – up to 60ppm higher for peaks and 30-40 ppm on average.
    See Fig. 2 at http://www.pnas.org/content/99/19/12011.full.pdf

  60. John Silver says:

    June 30, 2012 at 2:05 pm
    Me and my green friends demand 1200 ppm.

    But red “friends” demand just the opposite–people like Lisa Jackson, for example (apparently being “red” causes severe learning disabilities.)

  61. Gary Hladik says:
    June 30, 2012 at 8:52 pm
    … The ambient air temp (the “open box”) is the control for convection, and the salt window is the control for radiation.
    ======================================================
    Again, there was no open box to control convection or whatever in the Wood’s experiment.

    Never mind, anyway, the essential point about trapped radiation will not go away.

  62. Gary Hladik says:
    June 30, 2012 at 8:52 pm
    Greg House says (June 30, 2012 at 7:50 pm): “Wood’s intention was to demonstrate, that the ‘a widespread belief’ about “trapped radiation” is wrong.”

    You left out the part about “within a closed space covered with glass, and exposed to solar radiation”, you know, like in a greenhouse. I think I’m beginning to understand the origin of the “greghouse effect”. :-)
    =======================================================
    I guess too, that Arrhenius and others in the 19th century honestly believed in “trapped radiation” concept (it was not political back then) and simply extrapolated their (wrong) understanding of what is going on in the greenhouse to the atmosphere. They did not bother to check it, it was all “clear” to them. “Thought experiments”, probably. Things do not work this way, however.

    By the way, another warmist Tyndall believed for a while in “cold radiation” decreasing (!) temperature.

  63. Chas, thanks for the response. I love these discussions on this blog. So informative!

    I really like the similarity between CO2 for plants and O2 for humans. From what’s been said, humans aren’t affected by CO2, but rather O2 concentrations. In submarines, they can have 30,000 ppm of CO2 and not be affected because they pump oxygen into their air. So even if you have high CO2 levels, it won’t harm you if the oxygen concentration is also bumped up to adequate levels. With plants, it’s the same thing if I understand correctly. They only care about the CO2 concentration, not the oxygen level or whatever else. This is great information to have and something you never hear on AGW sites.

    Also, safe levels of CO2 is apparently 5000ppm assuming other factors remain the same. At 50,000ppm of CO2 for 30 min causes intoxication, and 5 minutes at 100,000ppm CO2 leads to unconsciousness.

  64. AndyG55 says:
    June 30, 2012 at 6:48 pm

    Frank, do some research on the mediacl affects fo CO2..
    ———————

    That’s what I was doing.
    ——————————–
    It is quite likely that what you sniffed off the top the brew contain a lot of other stuff apart from CO2.
    —————————-

    No doubt…
    ————————-
    CO2 in the air ONLY becomes an issue to humans when it starts to interupt oxygen transfer in the lungs. This is somewhere in the region of 10,000 ppm (iirc) ie 25 time the current atmospheric level..
    —————————————–

    I thought it was more than that – 4% or so…

    —————————————–
    It is NOT the CO2 that causes issues, it is the lack of oxygen transfer. Many other substances can also affect this oxygen transfer. eg smoke !
    ———————————

    Don’t give me that “oxygen deprivation” guff. We get quite enough dangerous misinformation from the PDA (Partnership for a Drug-free America) on that.

    The reason I stuck my snout in the crock in the first place was that I’d heard that CO2 was “interesting”. See:

    http://www.erowid.org/chemicals/carbogen/carbogen_info1.shtml

    Or better:

    http://www.cognitiveliberty.org/shulgin/adsarchive/salvinorinA.htm

    ———————————–
    Too much of anything will kill you !!
    ———————————–

    I believe that was my original point! :) (re: Mammoth Mountain)

  65. Arbuscular mycorrhizae fungi respond to higher CO2 by increasing more in the soil layer deeper than 15 cm. The mycorrhizae mass bulks up with Carbon it gets from a plant & that Carbon on the move fosters availability of soil Nitrogen.
    If the grown plant is an annual their relatively smaller root notably benefits from CO2 expanded mycorrhizae network increasing plants access to Phosphorus (P), since P isn’t too mobile in soil & might be out of reach of that plant’s own roots.
    Field plants are often hosts to Endophyte fungi in plant tissue above ground & if these are around more Carbon is available for mycorrhizae to bulk up on. However, we can’t make a generalization the two always work out great in higher CO2 because some types of plants hosting both at the same time show the two interact poorly.
    Still, some seed bearing grass-like plants hosting both endophytes & mycorrhizae will also produce more protein in seeds.

  66. Pre-Cambrian super high CO2 legacy according to Canadian oncologist Mark D. Vincent (U. Western Ontario):
    “Cancer cells are ancient alternative organisms, living protozoan-like fossils, foreign to their hosts because of deep origins elsewhere ….” (cancer cell resembles opisthokont, our uni-ciliated eukaryotic ancestors closely related to choanozoa )
    “… encrypted cancer cells in modern genome is a competitive struggle between a battle-scarred ‘protozoan’ from the Pre-Cambrian era and its ‘normal’ metazoan phenotype.”
    ” In the body but no longer of the body”
    “If an enterprising early cell ‘judged’ its metazoan was doing poorly, oncogenic reversion and host sacrifice could provide an escape from imminent death…. ”
    ” The universal traits exhibited by cancer cells represent the re-emergence of an ancient survival program.”
    “… the environments within which cancer cells flourish … intolerably low oxygen and pH, resemble the Pre-Cambrian – dooming to failure therapies that closely resemble the same challenges cancer cells evolved to defeat ( i.e. radiation, antimetabolites) ….”
    M. Vincent’s “Cancer: a de-repression of a default survival program common to all cells?: a life-history perspective on the nature of cancer” 2012 Abstract Quote =
    Cancer … evolutionarily conserved life-form, rather than just a random series of disease-causing mutations ….
    … traits, in all aggressive cancers = taxonomy (“phylogenation”), atavism (“re-primitivization”) and robustness (“adaptive resilience”)….
    … not convergent evolution, but the release of an highly conserved survival program, honed by the exigencies of the Pre-Cambrian, to which the cancer cell seems better adapted; and which is recreated within, and at great cost to, its host.
    Central to this program is the Warburg Effect, whose malign influence permeates well beyond aerobic glycolysis to include biomass interconversion and genomic heuristics.”

  67. “””””…..Gary Hladik says:

    June 30, 2012 at 6:37 pm

    Greg House says (June 30, 2012 at 3:11 pm): “And Wood did not need to show that in an enclosed space convective heat loss is prevented, I guess everyone new that.”

    Well, no again. Wood wrote in his “Note on the Theory of the Greenhouse”:……”””””

    Also Gary, the wavelength shift ia not even successful in trapping the radiation. The glass itself heats due to both its absorption of solar energy Likely including some UV (high energy photons) and IR in the 1-4 micron range, and also from conduction and convection from the hot air inside. The hot glass in turn then radiates in the LWIR OUTSIDE the “greenhouse”, so it is not such an effective radiation trap.

    Of course Woods’ experiment simply demonstrated that greenhouses do not heat by means of the “greenhouse effect” but by inhibition of atmospheric convection.

    His work (in that case) is unrelated to the atmospheric “greenhouse effect”, which also doesn’t quite work as claimed; but the physics of H2O , O3, and CO2 warming of the atmosphere by (temporary) radiant energy capture, is well established.

    What is in my view unproven is the extent of surface “heating” from atmospheric LWIR radiation.

  68. It might be helpfull to note that C3 is the most dominating type of photosynthesis. That is while C4 will not gain much from additional CO2. C3 will still have plenty absorption power over concentrations of today.

  69. Robert Brown:- Please look at the CO2 science web site (www.co2science.org) and read the experimental results on a large variety of plants grown in various atmospheric CO2 contents. whilst all plants do not grow at the same rate in the various concentrations they all do grow better.

  70. Frank said “Don’t give me that “oxygen deprivation” guff.”

    Its more to do with balance of oxygen and CO2 (see the submarine comment up there somewhere)

    The diffusion between the air in the lungs and the oxygen /CO2 balance in the bloodstream operates best when atmospheric CO2 is less than somewhere around 10000 – 15000ppm CO2, (if the oxygen content is near normal). Its not so much “oxygen deprivation”, but the imbalance in the atmospheric concentrations. In submarines they boost the oxygen content to so that the ratio stays within limits.

    Iirc we breath out around 30,00ppm, so as the atmospheric concentration climbs nearer that value, we are going to struggle more and more to transfer oxygen between the air and the bloodstream. Simple physics.

  71. So we now we have clear proof for the very first time that CO2 is plant food . Woopee Do! Pure obviousness.

    So we now also have proof that even though CO2 is a “trace gas” it’s incredibly important. Who could have guessed that?

    I wonder what are things are in the atmosphere, in trace amounts, but are also incredibly important. Err clouds for example. I wonder what the volume fraction of water in a cloud is?

  72. Indur M. Goklany, …’for some perverse reason’ you find empirical data more compelling than model results? Tsk … have you forgotten that models trump observation?

  73. Walt Stone (@Cuppacafe) says:
    June 30, 2012 at 6:18 pm

    Please repeat this experiment with phytoplankton and dissolved CO2.

    To take the example of where a continuous plankton recorder survey has been in operation for more than a half-century, in the Northeast Atlantic, during the corresponding rise in CO2, there has been an increase shown (Raitsos et al, 2005).

    A global study also found an increase, as seen from from measured chlorophyll, when comparing data in 1998-2002 to that collected during a previous mission in 1979-1986 (Antoine et al, 2005).

    Of course, part of the increase would be from other climate factors as well including nutrient upwelling. (A particularly blatant case is sea ice decline increasing plankton in the arctic, as even the NOAA reported, for a set of satellite observations covering 1998 to 2009
    http://www.climatewatch.noaa.gov/article/2011/sea-ice-declines-boost-arctic-phytoplankton-productivity ).

    Although a more indirect metric since also dependent on many other factors obviously, we can also tell phytoplankton is not doing badly from fish catches, as it is the basis of about the whole oceanic food chain:

    Phytoplankton have been around for a very long time, and CO2 levels were far higher before. One example estimate is http://i90.photobucket.com/albums/k247/dhm1353/Climate%20Change/PhanerozoicCO2vTemp.png with hundreds of millions of years ago there having been as much as 7000 ppm atmospheric CO2 at times (where the Geocarb III part of its CO2 is a more convenient presentation of ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/phanerozoic_co2.txt ). Current atmospheric CO2 is close to 400 ppm.

    Raitsos, D. et al.; Reid, P.C.; Lavender, S.J.; Edwards, M.; Richardson, A.J. (2005). “Extending the SeaWiFS chlorophyll data set back 50 years in the northeast Atlantic”. Geophysical Research Letters 32.

    http://dx.doi.org/10.1029%2F2005GL022484

    Antoine, D. et al.; Morel, A.; Gordon, H.R.; Banzon, V.J.; Evans, R.H. (2005). “Bridging ocean color observations of the 1980s and 2000s in search of long-term trends”. Journal of Geophysical Research 110.

    http://dx.doi.org/10.1029%2F2004JC002620

    But, as usual on topics close to this, http://nipccreport.org/reports/2009/pdf/Chapter%207.pdf is among the best reading. See page 42 and beyond of section 7.1.3 on aquatic plants including algae and phytoplankton, on lab experiments and production increase at elevated CO2.

  74. Mammals breathing 15% CO2, a high proportion, would still be in acceptable range of arterial blood pH at around 7.17pH (verses more ideal circulatory system wide average blood 7.4 pH).
    With yet a higher proportion of CO2 it is less the physical molecule of CO2 than the extra H+ ions diffusing into a cell’s interior that alters Calcium ++, Potassium + “recifier” and Sodium + channels.
    For example, when one of the K+ ion channels (inward rectifier) gets inhibited it depolarizes resulting in increased membrane excitability, which sets lungs up for sensitization of local nerve C-fibers to stimulii and that results in constriction of bronchii plus mucosa fluid retention.
    Altitude sickness sensations of headaches and heavy headedness involve similar dynamic.

  75. Presuming that all the oxygen in the atmosphere was produced by photosynthesis, why are oxygen and carbon dioxide so ridiculously out of balance in the atmosphere?

    If primary productivity increased during the recent warming (as mentioned above), why are there indications that oxygen content in the atmosphere is falling (recent post)?

  76. davidmhoffer says:
    June 30, 2012 at 1:22 pm

    Shhhhhh, don’t you realize this means that increased CO2 will cause the loss of endangered species of plants!!!

    /sarc

  77. AndyG55 says:
    June 30, 2012 at 3:30 pm

    Isn’t it VERY FORTUITOUS that we find coal and the released CO2 gives the plants a growth spurt just as the human population expands…

    Being a closet pendant, I’d say that that the word you really want here is fortunate, or perhaps felicitous.

    The adjective fortuitous is widely misused to mean fortunate, or lucky, but its original meaning is “by chance.” If you want a $5-word for lucky, try propitious, or auspicious – those probably correspond more closely to your accurate observation.

    So, while I quibble a little, and somewhat in jest about your choice of words, your point is a very good one, nevertheless.

    That people argue against burning our cheapest, most abundant source of fuel – which just happens to make our plants grow more vigorously in the bargain – only helps prove my previous observation, which should be elevated to a maxim: Yes, Fools Really Are That Ingenious

    The proof of the axiom is in the words of those who demonize coal and CO2.

  78. In the areas of tree kill at Mammoth Mountain, CO2 makes up about 20 to 95% of the gas content of the soil.”

    Don’t know a thing about CO2 root toxicity, but 20 to 95% leaves a lot of room for SO2, a vastly more toxic volcanic gas.

  79. AndyG55 says:
    July 1, 2012 at 3:52 am

    Frank said “Don’t give me that “oxygen deprivation” guff.”

    Its more to do with balance of oxygen and CO2 (see the submarine comment up there somewhere)

    The diffusion between the air in the lungs and the oxygen /CO2 balance in the bloodstream operates best when atmospheric CO2 is less than somewhere around 10000 – 15000ppm CO2, (if the oxygen content is near normal). Its not so much “oxygen deprivation”, but the imbalance in the atmospheric concentrations. In submarines they boost the oxygen content to so that the ratio stays within limits.

    Iirc we breath out around 30,00ppm, so as the atmospheric concentration climbs nearer that value, we are going to struggle more and more to transfer oxygen between the air and the bloodstream. Simple physics.
    ——————————————–

    You forgot the “sarc” tag after “simple physics”. :)

    Let me make sure I understand our area of disagreement (if any). Are you saying that CO2 does not have psychedelic properties?

    I probably shouldn’t have mentioned it – we don’t need the DEA competing with EPA to demonize CO2! I should mention that there’s no danger of CO2 catching on as a recreational drug. As I’m sure you know, our respiration rate is determined not by O2 concentration in the bloodstream but by CO2 concentration. So a whiff of (concentration unknown, but high) CO2 makes you pant like a puppy-dog and feel like you’re suffocating. Might be useful for “dry waterboarding” (you did not hear this from me!), but not much fun despite the “trippy” effects.

  80. ps.. In the lungs diffusion through the semi-permeable membrane is oxygen one way and CO2 the other way, so both atmospheric concentrations matter. If you deliberately inhale a very high concentration of CO2, you most definitely will have issues with both.

  81. There has been much wringing of hands and gnashing of teeth over the carbon dioxide accumulation in the atmosphere. The “Warmists” miss the point about it’s affect. The “Deniers” over emphacize it’s “lack of effect” and so we continue to discuss the impact of the compound around the wrong process.
    There are enough studies suggesting a slightly negative feedback loop related to CO2 concentrations.
    My take on the general issue related to the slightly higher temperatures observed in the most recent past century are as follows:
    1. The temperature on this planet over the past 5 million years has gone down on long average around 5 degrees C. In the process, the temperature has followed a sawtooth like pattern with a very quick rise followed by a slightly slower drop rate with a total swing of around 8 degrees C. So far, the current temperature has not yet equaled the value of the peak of all of the previous interglacials. We are still around two degrees below the most recent previous peak. As temperatures continue to rise, more methane and carbon dioxide are released into the atmosphere by melting permafrost. Yes, the ocean absorbes the carbon, but not enough to override the increase in the atmosphere. Also, plants, enjoying the higher carbon concentration grow more, increasing their cooling effect on the overall process.
    2. Plant respiration is a cooling process which counters and slows tempreature increases but is not the main process related to the temperature cycle. Rather, it is a moderator. Further, the development of C3 photosynthisys may be responsible for the change in the glaciation cycle from an average of 41,000 years to slightly more than 100,000 years, which has been the case over the past four cycles.
    3. Four degrees below the peak or two degrees below current is enough to start significant ice accumulation and so to change the surface albido. The ice accumulates over the polar caps first and then begins to accumulate over land masses. In the past 50 million years – give or take a few million, the land masses are more in the northern hemisphere and so, there is more accumulation on the northern land masses and the northern hemisphere has experienced larger temperature excursions than the southern. Regardless of hemisphere, as the ice accumulates, several things happen. First, the albido begins to change and more radiation is reflected away. At the same time, ice accumulation lowers sea levels. Lower sea levels result in more land surface area. Initially, I suggest, more plant growth takes place, which adds to, and speeds the cooling already in progress. However, the cooling retards plant growth. In addition, cooling would retard the disintegration of the plant materials, thus trapping carbon, as in coal, but well before gelogic processes would create coal. Rather, this material is simply trapped in the soil, holding the carbon out of circulation. Remember the huge accumulations of carbon dioxide and methane in the permafrost?
    4. How do we get the temperature to begin to drop in the northern hemisphere to initiate the next glaciation cycle? As the temperature rises overall, the ocean temperatures also rise. Temperature differential drives the Gulf Stream. The Gulf Stream carries warm water north along the American Atlantic Coast. The water is cooled by Arctic waters and then flows South effectively lowering Equitorial ocean temperatures. The Gulf Stream has an “averaging” effect on the oceanic temperature. Now, we talk about the Arctic Ice Extent and use that as a measure of warming. We are missing a possible point here. This point is related to the condition of the ice as opposed to the extent. There are a number of folks suggesting the Arctic Crossing will be available very soon. This is because, while ice still covers the Arctic area, it is not as hard and ice breakers can push through it more easily. By “hard” I mean the ice is much closer to thawing but hasn’t actually melted. I suggest that the “trigger” for the cooling, leading to our next glaciation is related to the actual “Arctic Sea Tempreture” instead of the momentary ice extent. At some point, the “driver” for the Gulf Stream will loose effect as a result of insufficient temperature differential, thus resulting in a major change in the flow. In effect, the Gulf Stream will stop or at least slow to the extent that the Arctic Sea will again freeze.
    5. Once the cooling is well under way, the sea levels continue to drop. However, because of lower overall temperatures, plant growth begins to decline. This means increasing areas of land mass that is not fully covered by plant growth. Here the moderating tendency of plant growth to cool the environment is effectively reduced. In addition, these larger areas of land mass not covered by vegitation change the albido further to a more absorptive form and warming begins. The albido based warming is a positive feedback process in that as the warming progresses, ice melts exposing more land mass that does not have plant growth. The newly exposed land area represents significantly more total area than the loss of area resulting from the sea level rise related to the warming process. Hence the albido continues to accelerate the warming. Plant migration into the newly exposed areas is a slow but progressive process and eventually will overtake the warming effect of the bare land.
    6. We are today at that threshold before the cooling can start. Because deforistation, human influence has effectively interrupted or delayed the beginning of the cooling process by reducing the overall global vegitation coverage. However, the continuing degradation of the Arctic ice, even if it has not receded in area, is an indicator of Arctic Ocean warming. This warming will eventually cause the shift in the Gulf Stream flow mentioned earlier.
    7. Is this something we will see in our lifetimes? I don’t know. However, there are ice core indicators pointing to very sudden reversals in temperature movement in the past.

  82. As a doctoral student in Plant Sciences, I would be curious to know if a CO2 fertilization effect is similar to a N fertilization effect. Up to a certain point increased N typically produces increased biomass. However, biomass is not marketable yield. There are crop species that require precise timing of applications, and too much or poorly timed applications produce increased canopy growth at the expense of marketable yield. In a few years I may be set up to study these questions.

  83. Per Mammoth Lakes / Mountain:

    It is a volcano. You get all sorts of odd gas poisonings on an active volcano. Concentration can run to 100% for a variety of gasses. Says nothing about likely CO2 levels globally. It also diffuses up through the soil (again up to 100%) and can be quite hot and dry.

    Someday it will “blow” again and we get a SuperVolcano from it that will take out much of the desert Southwest (but hopefully not all the way to San Francisco… at least the projected ash zone stops a few dozen miles short of my home :-}

    @Henry:

    Talk to a farmer. Nitrogen and CO2 are different. CO2 generally promotes growth. Nitrogen promotes leaves.

    http://www.thegardenhelper.com/fertilizer.html

    Nitrogen for greens. Phosphorus for fruits and roots. Potassium for flowers and strength.

    CO2 for any and all structures. Trace minerals as needed for enzyme systems.

    @Walt Stone (@Cuppacafe)

    http://www.co2science.org/subject/p/summaries/phytoplankton.php

    Even though photosynthesis in many marine and freshwater phytoplankton appears to be saturated under current environmental conditions, Raven (1991) suggested that these species, many of which employ carbon-concentrating mechanisms, could well decrease the amount of energy they expend in this activity in a CO2-enriched world of the future, which metabolic adjustment would leave a larger proportion of their captured energy available for fueling enhanced growth. To explore this possibility more thoroughly, Gordillo et al. (2003) studied the CO2-induced growth response of the microalgal chlorophyte Dunaliella viridis, which possesses a carbon concentrating mechanism and has been used as a model species for the study of inorganic carbon uptake. Specifically, they batch-cultured the chlorophyte, which is one of the most ubiquitous eukaryotic organisms found in hypersaline environments, in 250-ml Perspex cylinders under controlled laboratory conditions at high (5 mM) and low (0.5 mM) nitrate concentrations, while continuously aerating the cultures with air of either 350 or 10,000 ppm CO2. So what did they find?

    Atmospheric CO2 enrichment had little effect on dark respiration in both N treatments. Likewise, it had little effect on photosynthesis in the low-N treatment. In the high-N treatment, on the other hand, the extra CO2 increased photosynthesis by 114%. In the case of biomass production, the results were even more divergent: in the low-N treatment elevated CO2 had no effect at all, but in the high-N treatment it nearly tripled the cell density of the culture solution.

    Gee… plants are plants. Nitrogen limited, no change. With available nitrogen, they grow better with more CO2.

  84. Field plants response to higher CO2 is not linear; that growing soil by the 3rd year of increased CO2 growing conditions has boosted Nitrogen mineralization for more soil Nitrogen bio-availabilty to the plant now growing there. Of course if there were nitrogen fixing root nodule possessing plants grown during the interim the exact % of bio-available Nitrogen will be higher (ex: crop rotation planted soybeans the 1st or 2nd year).
    It is going into the 3rd & 4th years that higher CO2 really provokes greater bio-mass in that soil.
    The higher CO2 growing plants over the first 2 years has provided enough Carbon for soil microbials to structurally form. Then as a portion of the underground microbes die back, some residues of their microbial mass Carbon will go on to be outgassed while the dead microbes accumulated Nitrogen mostly stays in the soil for re-use by plant grown there.
    More Nitrogen available below ground, as a long term consequence of CO2 dynamic with soil
    microbes, will give above ground more mass of plant shoots above ground. It is a feature of the natural growing domain’s ecosystem providing long term no-till fertilization ( which is added to more complicatedly by specific plant debris).
    Moreover, any underlying higher % of CO2 also means a relative decrease in that plants uptake of CO3 (ozone) & thus prevents ozone’s own action that otherwise restrains % of free Carbon convertability into above ground biomass of plant shoots.

  85. Extra C-O2 is plant food – is this the reason all autos with fossil fuel engines in the USA are required to have CAT’s; must convert the CO into CO2 or else!

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