CO2 and crops: NAS vs. science

WUWT regular David Burton writes:

One of the most pernicious examples of disinformation promoted by the Climate Industry is the claim that manmade climate change from CO2 emissions threatens agriculture and “food security.” That’s the exact opposite of the truth. CO2 is “plant fertilizer,” and hundreds of agricultural studies have shown that higher CO2 levels are dramatically beneficial for agriculture, to levels far above what we can ever hope for outdoors.

Most plants grow best with daytime atmospheric CO2 of at least about 1500 ppmv. That’s about what CO2 levels are thought to have averaged during the Cretaceous. It’s 1090 ppmv higher than the current average outdoor level of about 410 ppmv.

In other words, most plants would grow best if CO2 levels were increased by more than eight times the measly 130 ppmv by which mankind has managed to increase CO2 levels since the “pre-industrial” Little Ice Age. (Levels even higher than that wouldn’t hurt plants, but they wouldn’t help much, either.)

https://sealevel.info/co2.html?co2scale=2
clip_image002
(click to enlarge)

That’s why most commercial greenhouses use “CO2 generators” to raise daytime CO2 to about that level. It makes the plants healthier, faster-growing, and more productive.

Note: There are several different kinds of photosynthesis. Plants that use “C3” or “CAM” photosynthesis benefit the most from higher CO2 levels. “C4” crops benefit the least, but even C4 crops benefit when under drought stress. Most crops use C3 photosynthesis. There are only four important C4 crops, all of them grasses: corn [maize], sugarcane, sorghum, and millet.)

https://www.sealevel.info/C3_and_C4_Pflanze_vs_CO2_Konzentration_2018.png
clip_image004
(dependence of the rate of photosynthesis on the amount of CO2 in the air in C3 and C4 plants, from https://de.wikipedia.org/wiki/Photosynthese; click to enlarge)

The value of higher CO2 levels for agriculture is not a new discovery. Svante Arrhenius wrote about it in 1908, and cited a source from as early as 1872. Arrhenius predicted that:

“By the influence of the increasing percentage of carbonic acid [CO2] in the atmosphere, we may hope to enjoy ages with more equable and better climates, especially as regards the colder regions of the earth, ages when the earth will bring forth much more abundant crops than at present, for the benefit of rapidly propagating mankind.”

In 1920, Scientific American reported the results of German greenhouse and F.A.C.E. experiments with CO2 supplementation. The experiments were so spectacularly successful that SciAm called anthropogenic CO2 the precious air fertilizer.” From this photo, which accompanied the article, you can certainly see why:

SciAm 1920: Carbonic Acid Gas to Fertilize the Air
clip_image005
(click to view article)

Over the last century, many hundreds of studies have measured the large benefits of higher CO2 levels for most crops:

https://sealevel.info/CO2-pineGrowth100120_white_bg.png
clip_image007
(Dr. Sherwood Idso showing the effect of CO2 level on pine trees; click to enlarge)

But the National Academy of Sciences would have you believe that global warming threatens agricultural productivity. So let’s examine that claim.

Here’s a recent article from the Farm Bureau, reporting preliminary U.S. state-by-state corn and soybean yield numbers for 2018:

Farm Bureau 2018: Corn and Soybean Yields are YUUUGE
clip_image009
(click to view article)

Of course the headline obviously suggests that climate change hasn’t hurt corn and soybean production, so far. But that’s not the most interesting part of it.

Look at the wide distribution of states, which grow corn. In this map, from the article, you can see that Minnesota’s 2018 corn yields averaged 191 Bushels Per Acre (BPA), and Mississippi’s corn yields averaged 185 BPA. The “breadbasket” states of Illinois and Iowa both had even bigger bumper crops, with yields above 200 BPA:

https://www.fb.org/images/uploads/_900w/Yuge_fig_1.jpg
clip_image011

Now, compare that map with this growing-zone map (courtesy of arborday.org). In it you can see that Minnesota and Mississippi are about four climate/growing zones apart. Minnesota is mostly zone 4, and Mississippi is almost entirely zone 8. Illinois and Iowa are a mix of zones 5 & 6:

https://sealevel.info/zones-2015_700x420.png
clip_image013

U.S. climate zones span 10°F, so the center-to-center difference between four zone numbers is 40°F = 22.2 °C.

However, in this map you can see that Minnesota’s corn is mostly from the southern half of the state, which is a mix of zone 4 and zone 5, and Mississippi’s corn is mostly from the northwest half of the state, which is upper zone 8.

http://ctgpublishing.com/united-states-corn-production/
clip_image015

So the average temperature difference between the middle of the prime corn-growing regions of the two states is a bit less than 40°F, I’d call it about 33 ±2°F.

In Celsius, that’s a temperature difference of 17.2 to 19.4 °C (midpoint 18.3°C), between Mississippi (185 BPA) and Minnesota (191 BPA).

In other words, it is plain that an average temperature difference of about 18°C has little effect on corn yields.

Many other major crops are even less climate-sensitive:

● Wheat is profitably grown in zones 3 through 9, from Saskatchewan to south Texas, a temperature range of over 35°C:

https://sealevel.info/wheat_growing_regions_usa_and_canada_700x840.png

clip_image017

● Maine & Florida are both major producers of Potatoes:

http://potatoesusa.com/us-potato-industry/us-growing-regions
clip_image019

● Soybeans are grown from Louisiana & Mississippi to Minnesota & Canada:

https://www.fb.org/images/uploads/_900w/Yuge_fig_4.jpg
clip_image021

What, then, are we to make of this PNAS paper?

Zhao C, et al. (2017) Temperature increase reduces global yields of major crops in four independent estimates. Proc Natl Acad Sci USA 114:9326–9331. doi:10.1073/pnas.1701762114

From the title you would probably assume that they found anthropogenic climate change causes crop yields to decline, because negative impacts of temperature increases exceed the positive impacts of CO2 fertilization and improved drought resistance from higher CO2 levels. That’s what you’re supposed to think, and that’s how the press release reported it:

Climate change will cut crop yields,” said the caption on Phys.org, and called the little five-page paper “a major scientific report.”

Global Warming Will Sear Three of Four Major Grain Crops,” said the caption on Haaratz.

But if you read the paper, or if you read Eric Worrall’s excellent 2017 analysis of it on WUWT, you’ll discover that the authors did not actually say that. Instead, they wrote that they were discussing what they think would happen to yields in an imaginary world “without CO2 fertilization, effective adaptation, and genetic improvement.”

Of course “without CO2 fertilization” means they’re ignoring the beneficial effects of higher CO2 levels, which obviously divorces the paper from any pretense of presenting predictions of future reality.

But it’s even worse than that. Can you guess what their assumption of no “effective adaptation” to a warming climate actually means?

For annual crops, “effective adaptation” means adjusting spring planting dates, and perhaps adjusting cultivar selection. That’s all.

It’s not rocket science. In America’s heartland, moving the planting date up by about six days compensates for 1°C of warming:

https://www.currentresults.com/Weather/Kansas/Places/wichita-temperatures-by-month-average.php
clip_image023

So +4°C of warming is equivalent to planting about 24 days late.

The assumption of no “effective adaptation” to warming means these 29(!) authors assumed farmers are all idiots, who can’t figure out when they should plant their crops. (Projection, maybe?)

It’s utterly preposterous. The reality is that most farmers are not idiots, anthropogenic CO2 is highly beneficial “air fertilizer,” and the further that CO2 levels rise, the more productive farms will become.

That fact is true for the great majority of crops, nearly everywhere in the world. Yet the NAS has been promoting the anti-scientific claim that rising CO2 levels are bad for agriculture, for years. This 2011 NAS / NRC propaganda graph is a particularly outrageous example:

https://nas-sites.org/americasclimatechoices/more-resources-on-climate-change/climate-change-lines-of-evidence-booklet/evidence-impacts-and-choices-figure-gallery/figure-28/
clip_image025
(click to enlarge)

Notice the red “US Maize” and purple “India Wheat” traces, and where they intersect the 4°C line. You can see that they’re predicting that in the event of a 4°C temperature increase, U.S. maize (corn) yields would decline by a devastating 60%, and wheat yields in India would fall 68%.

(Of course such a large temperature increase is thoroughly implausible, but never mind that. That’s a different rant, for a different day.)

Today’s rant is this:  That NAS / NRC graph is a lie.

If a mere 4°C of warming were actually that destructive to corn yields, it would obviously be impossible to profitably grow corn even in Tennessee & Kentucky (zone 7, 174-175 BPA in 2018), let alone Mississippi (zone 8, 185 BPA).

Likewise, if a mere 4°C temperature increase were actually that destructive to wheat yields, then it would obviously be impossible for North Americans to cultivate wheat across seven climate zones, from Saskatchewan to south Texas, spanning an average temperature range of about 35°C.

That NAS / NRC graph is utter nonsense. But even though it is old, it’s still being used by climate change zealots to mislead people. I stumbled across it because someone posted it in the comments on an article at ArsTechnica. (I’m currently banned for a week there, for “ignoring moderation,” because I disagreed with their leftist moderator. My first comment there [screenshot] has been deleted, too, but some of the others are still there. They look “faded” because the ArsTechnica comment system fades-out comments with lots of downvotes.)

On March 22, 2012, Rud Istvan did a wonderful, in-depth demolition of that graph, on WUWT & ClimateEtc:

https://judithcurry.com/2012/03/22/nrcs-artless-untruths-on-climate-change-and-food-security/

https://wattsupwiththat.wordpress.com/2012/03/22/nrcs-2011-climategate/

Yet, despite their propaganda graph having been completely debunked, the NAS is still disseminating it, to promote the climate scare.

Here it is on their web site, on p.28 of a little 40 page propaganda booklet, which appears to be designed to be used as a resource by schoolteachers:

https://nas-sites.org/americasclimatechoices/more-resources-on-climate-change/booklet-warming-world-impacts-by-degree/

http://dels.nas.edu/resources/static-assets/materials-based-on-reports/booklets/warming_world_final.pdf

Here it is, in convenient PowerPoint format, for incorporation into your talk at the local garden club (slide 21):

http://dels.nas.edu/resources/static-assets/exec-office-other/climate-change-figures.ppt

(The file metadata indicates that the slides were created by “Rebecca” in June, 2013 — more than a year after Rud had discredited the graph.)

It’s also on p.161 of this free 299-page ebook:

https://www.nap.edu/catalog/12877/climate-stabilization-targets-emissions-concentrations-and-impacts-over-decades-to

If Zhao and his 28 co-authors really believe, as they claimed in their PNAS paper, that correctly assessing the impact of climate change on agriculture is “critical to maintaining global food supply,” then it is incredibly cynical of them and the NAS to publish misleading papers and graphs which encourage policymakers to take steps that will actually reduce that the global food supply.

I’m beginning to wonder: Does the “A” in “NAS” is still stand for “Academy of,” or does it now stand for “Anti-,”?

189 thoughts on “CO2 and crops: NAS vs. science

  1. I do suppose that if someone was foolish enough to plant a variety of maize or wheat adapted to Minnesota in Mississippi, one could get an inferior yield.

  2. “So +4°C of warming is equivalent to planting about 24 days late”
    If it’s warmer, wouldn’t they be planting 24 days earlier ?

    • Re-read that. He is saying that planting 24 days later would be equivalent to planting at the regular time if temperatures were 4C higher.

      • Yes, but so what? The time required for a crop to mature is pretty much the same. Warming would increase the length of the growing season at both ends. Having more time to plant and harvest can only be a good thing.

        • Here in Sweden farmers have always started planting as soon as the snow has melted and the ground has dried out enough, so “adaptation” will occur automatically.

          • For them, a longer growing season could only be a good thing, and yet this area of the world is one of the most strident of warmists at all the conferences.

        • Few occupations discuss weather as extensively as farmers. Degree-day calculations gives some predictability on plant growth stages – when to plant, fertilize, spray, and when to expect harvest. Check it out on the web.

  3. Note: I wrote, ““C4” crops benefit the least, but even C4 crops benefit when under drought stress.”

    But Craig Idso points out that a new paper reports that corn (maize), which is the most important C4 crop, benefits from eCO2 more than you would expect for a C4 plant:

    http://www.co2science.org/articles/V21/oct/a17.php
    https://www.tandfonline.com/doi/abs/10.1080/00103624.2018.1448413

    See also, http://www.co2science.org/subject/a/agriculturemaize.php and http://www.co2science.org/data/plant_growth/dry/z/zeam.php

    Thanks, Craig!

    • Yes, CO2 is more than fertilizer. It’s the fundamental building block of all life. Like water, it is essential. Plants can be overwatered, but they can’t really be over CO2’ed as the optimum level of CO2 is at much higher levels.

    • Under drought stress C4 grain plants will hold their longer under eCO2; early ageing of leaves otherwise (under drought) results in faster senescence (being old). C4’s later occuring senescence (in drought) results in more leaf biomass & C4 grain plants (some, can’t say if all) will take about an extra week to start filling their grain (in drought).

      Drought after anthesis (flowering) can cut grain yields by up to 30%; while keeping green leaves during grain filling yields more grain. Late in life C4 grain plants’ leaves hold more amino acids under eCO2 than ambient CO2 leaves do late in life.

      eCO2 partitioning more carbon for storing in the roots allows these to be re-mobilized under drought to send upwards for grain filling. Grains filling under eCO2 will have more cysteine (made from chloroplast’s sulphur); vital because cysteine (plus glutamine & ATP via an enzyme having glycine on it’s C-terminal) cobbles together the cellular protective molecule glutathione.

      eCO2 in C4 drought grains will also have more of certain molecules (sorbitol & glycerol) that are useful for coping with drought stress; in part, because eCO2 drives increased CO2 assimilation. This allows more electrons to be used when plant getting lots of light (technically more photons “captured” regardless of photo-synthesis) when drought threatens to stress the leaves – in simple terms the eCO2 growing plant can use that energy chemically, bumping up the amount of electrons used by making compounds (& sugars) that are protective.

      Many assume that eCO2’s reduction of stomatal conductance (leaf pores more closed) is how C4 plants get better yields in drought than the same C4 gets in ambient CO2 + drought. The dynamic is not really linear; yes, for most of it’s days the C4 grain plant under eCO2 + drought will exhibit less open stomata (than ambient CO2 + drought). However, late in it’s viable days this will change; the eCO2 + drought C4 grain plant will actually have more stomatal pore conductance than the other (ambient CO2 + drought C4 plant).

    • Corn yield in the early 60s was around 80 bushel per acre (boa)in Iowa. It is now 200 bpa. A corn kernel is nearly 50% carbon. A bushel weighs 63 lbs per bushel. So, among friends let’s just say that is an increase of 120 x 30 = 3600 more pounds of carbon just with the kernel per acre.

    • I just spent a little time reading the Idsos’ wonderful CO2 Science site, and elsewhere, about the other three main C4 crops.

      It seems that sugarcane (the 2nd-most-important C4 crop?) also benefits pretty dramatically from eCO2:
      http://www.co2science.org/data/plant_growth/dry/s/saccharumo.php

      I also read, to my surprise, that, like legumes and alder trees, sugarcane can fix its own nitrogen via symbiotic bacteria. That might have something to do with the surprisingly large benefit it enjoys from eCO2, which would be consistent with C3 legumes (which also fix their own nitrogen, and benefit very dramatically from eCO2). Perhaps the plants’ ability to fix nitrogen means that there’s less risk that faster-growing crops will need more nitrogen fertilization than they get.

      The benefits of eCO2 for sorghum (the 3rd-most-important C4 crop?) are unclear. Results vary. Some studies show benefits, but two studies show benefits only under dry conditions:
      http://www.co2science.org/data/plant_growth/dry/s/sorghumb.php

      Millet (the 4th-most-important C4 crop) is similarly unclear. One study says it benefits from eCO2, another says it doesn’t:
      http://www.co2science.org/data/plant_growth/dry/p/panicumm.php

  4. The reason for the insensitivity to climate zone is largely the result of having short season versus long season varieties to plant. One can match variety to the reliable growing season. This is also a major factor in the yield. I grew corn in eastern Wyoming, which barely shows a corn growing region on the maps. We planted a lot of corn in the 87 to 95 day varieties, and considered it a bumper season if we got 144 BPA.

    Now, a longer growing season, if reliable, would allow one to plant longer season varieties, and with appropriate inputs (water, fertilizer) yields would rise. Agriculture is always an optimization problem of balancing various trade-offs.

        • You certainly could if you sow the first crop in the autumn to over winter, alot of winter barley sown here, gives them 2 harvests, winter then spring sown, winter sown provides best tonnage pa.

          winter sown looks like long grass when the spring barley is being drilled.

      • This is happening already, and not due to global warming. I have a friend who is a farmer in New Jersey who has abandoned growing corn varieties for sales as fresh ear corn. He can’t sell profitably when the price offered at market has to compete with Georgia growers who are getting two crops of ear corn per season. Higher temperatures in the South, combined with matched cultivars are totally changing the market for this crop.

    • There you go talking common sense and using practical examples. No wonder no alarmists come calling to engage you as a speaker.

      What do farmers know about farming? It’s a good job we don’t depend on them for our food supply. Thank goodness we have Loblaws and the Walton family to thank for that service.

      Sometimes I wonder if farmers understand anything at all about the weather and climate.

      Obligatory /sarc

      • Spread the grant funding.

        Spread the prestige of being associated with the grant-funded study.

        Why make the funding to one author, when you can make it to 29? –28 more potential famous people bought with that funding? There’s grant-receiving strength in numbers.

    • Simple, gets their names in print. Part of the “Publish or perish” culture, that infests universities these days.

      • In Neil deGrasse Tyson’s CV is a paper where he is one of 41 “authors.” He actually only has 14 papers total in his CV, IIRC.

    • Wrong. It means that 29 CV:s will have another paper on it. “If you scratch my back, I will scratch your”.

      Also known as MPU/MNA “Minimum publishable unit, Maximum number of authors”.

    • It has been said that the quality of any study is inversely proportional to the number of authors. This paper could be used as a case study. Does author #29 actually understand what the lead author actually said? Did he/she even read the paper? In some cases of academic fraud, people have added fake co-authors without even telling them, although I don’t say that this has happened with this paper.

      • I recently discovered that I was listed as the lead author on a paper based upon analysis I performed with an instrument which was so crapped up with junk from previous run that I abandoned the research after my advisor refused to allow me to clean it. I left industry and entered graduate school because of all of the lying and BS I encountered a discovered the same thing happening. The Department head who recruited me eventually left for another university. I guess that I should have followed him.

  5. Carbon Based Life Forms participate in the Carbon Cycle.

    Atmospheric Carbon Dioxide is necessary to complete the Carbon Cycle.

  6. “Today’s rant is this: That NAS / NRC graph is a lie.”
    Maybe one of them “accidentally” put the graph upside down…..again. LOL

    • No. I traced the graph origins in my 2012 post here and at Judiths. It was a deliberate misrepresentation made for a congressional briefing. The provable criminal felony is 18USC1001.
      And the underlying maize yield paper comprises scientific misconduct for deliberately leaving a crucial, experimentally known covariance term out of the multiple regression.

      Dave Burton was perhaps too polite in his condemnation.

  7. Of course, it wouldn’t be as scary if the warmists didn’t press the narrative that no matter what the future holds as far as climate, it’s going to be bad. More scary means more funding.

  8. “Food security” is cultural marxist sloganeering, to justify global government control of agriculture.

    Billions will die.

    • Should the alarmists succeed in reducing global CO2 levels below 180ppm, which many if the severely mislead seem to desire, then billions of people (and most carbon based life) would die

      • That experiment could be done, and maybe has been. In a group of small greenhouses with lowered CO2, say, by 10 ppm increments from 200 to 50. Plant corn, water, maintain temperature, measure growth and yield.

        Perform the experiment in each of the growth zones.

        The result would be data, not speculation or models.

  9. Although the press is always fast to link just about anything to Manmade Climate Change, I read a story two weeks ago about the fact that “the Sahel is becoming greener thanks to the efforts of the local farmers”.
    Right… I guess local farmers just weren’t trying hard enough during the 20th century…
    (CO2 has nothing to do with. CO2 bàààààd.)

    • The BBC has just had a feature blaming the problems in Mali on climate change.
      This despite the population doubling every 20 years, and serious problems with terrorist groups.

  10. Great thing about having the CO2 monitoring station in Hawaii is that it is in the middle of the ocean and not close to any continuous erupting volcanos…..During the flower phase of certain plants, a bigger yield can be obtain by producing CO2. Many greenhouse , while heating in winter, will let a gas heaters produces of combustion vent directly into greenhouse…Extra CO alarms just incase combustion goes haywire

    • I visited an Ontario greenhouse, and while there, the CO2 truck arrived with a delivery. They used the gas as part of their greenhouse procedures, even in summer.

    • My reply is yet again lost in cyberspace.

      The Mauna Loa (an active volcano) CO2 observatory lies on the same island with the continuously erupting Kilauea volcano, and three other volcanoes.

      • Even scientists are smart enough to figure out which way the wind is blowing, and not take readings when they are down wind of the volcanoes.

        • Keeling tried to homogenize out local sources of CO2. One might wonder how effectively.

          Mauna Loa is an active volcano, to include essentially continuous venting. No matter which direction the wind blows, it comes from an eruptive direction. If not from Mauna Loa itself, then from Kilauea, Hualalai, Mauna Kea or Kohala. Haleakala on nearby Maui is also probably not extinct, but dormant.

          http://www.soest.hawaii.edu/gg/HCV/mloa-eruptions.html

          Recent exceptional activity from Kilauea must have the data homogenizers whirring night and day.

          • To which I could add Lo’ihi Seamount, the new, still submarine volcano forming off the Big Island, as the Pacific Plate moves over the Hawaiian Hotspot.

            Mauna Loa itself also has submarine vents.

        • Yet again my comment fails to post. It contained only a single link, since I didn’t include a source on how the Keeling Curve tries to handle local CO2 sources.

      • Is the output of CO2 from Mauna Loa volcano consistent over time?
        Why was it chosen as the measuring point for CO2?

        • It varies, but, at least from submarine vents, it’s almost always outgassing.

          The idea was that it would be a good locale for measurement, assuming that local sources could be controlled for. Better a tropical (barely) island mountaintop, even if volcanic, than close to a temperate zone continental city with high and greatly varying emissions.

  11. Dave great post (-:

    CO2 is more than fertilizer. The Nitrogen, phosphorus, and potassium in commercial fertilizers are needed in relatively small amounts, but CO2 is an essential ingredient. It is the feed stock of photosynthesis. It is as essential to the chloroplasts in the green leaves that produce the simple sugar as iron ore is essential to the smelter producing steel.

  12. I spent a career in the seed industry in those bread basket states:

    1) Corn is currently grown from the equator to Canada, and breeders are now developing corn to plant in Alberta. We have the genetics to “adapt” to almost any climate, as long as it rains.

    2) Soybeans and all other beans have increased yields in higher CO2 environments, go to Google scholar and do a search. The CO2 window downwind from cities even increases yields slightly.

    3) The application of genomics means we have the best breeders with the best ever in the planets history right now.

    Namely, don’t worry about agriculture productivity in a warming world, we got this. There might be a problem if a truly cold period sets in though….just sayin’

  13. Scary headlines have always had more value in climate ‘science ‘ than facts.
    Partly because you can bet most people will never bother to check the facts and partly because you need these to keep the grant money flowing in and to let others know you are ‘one of them and not an evil denier ‘
    The authorises merely acted the normal way for the rea they work-in, which in turn tells us much about the nature of the area.

  14. Bear in mind that in a lot of these areas prairie grass used to grow until Mr John Deere Steel plough was able to tear through the grass and leave behind soil ready for planting.

    Prairie grass is drought resistant illustrating the climate of vast areas. It’s a miracle that year on year there are bumper crops illustrating benign weather.

    Interesting to note that during the 30s Great Drought, the shortgrass of Nebraska and Kansas spread hundreds of miles to the east into the mixed grass region, while the mixed grass spread hundreds of miles into the tallgrass.

    • Prairie grass being drought resistant has little to do with why it dominated this region, where drought happens but not regularly. Go look at all the natural forest still left in IL, WI, IA, and MI. Prairie grass dominated as it is a perrennial that can survive the cold winters, and can outcompete trees on many types of soil. Areas that are not great for farming because of drought were poor places for pretty prairie grass too (but they were all that would grow), like NE and CO.

    • What? CO2 levels dropped and caused C4 plants to develop as they can limit the CO2 reaching the photosynthetic enzymes. We are already at the point where C3 and C4 yields are competitive, and as CO2 goes up the beans will do better while the corn and wheat will stay the same. BTW, we know almost everything about plants physiologically and developmentally and we know their genomes, for almost all land plants, to the letter. What do you mean?

      • Mosh is having another tantrum.

        He’s trying to parallel the claims of some that since CO2 is a trace gas it can’t have any impact on the climate.
        He’s also trying to parallel those that point out that since there is so much we don’t know about the climate it’s too early to proclaim panic.

        • No, C4 plants are losing any advantage they did have because of CO2, they still do better in drought, and corn has had a few hundred years of unprofessional and plant breeding so it is pretty hard to replace. Field corn is far from the average plant, C4 or not.

    • Another drive by Moshing.
      The fact that plants thrive with more CO2 is known, and has been well known for over 100 years.

      • What’s more, it can be replicated with proper scientific experiments under controlled conditions, in a relatively short space of time.

        The global warmulans, by contrast, assert something that cannot be tested with any kind of controls, and which cannot be falsified until after the protagonists are dead or unaccountable for any lies told

        Now which one comes closest to the ideals of science?

    • So much that YOU don’t understand Mosher. Farmers are different. They understand about agriculture and plants.
      B

    • co2 is a deadly gas, because if you breathe car exhaust for very long you’ll die
      we can pinpoint exactly what the climate is doing and will do, because of what our models driven by ginormous computers tell us, and unless we go back to living in dark mud huts and caves and eating twigs, we will kill the planet

      • Yeah I don’t understand why Mosh isn’t pointing this out? Doesn’t he know that CO2 is deadly to humans? I mean with these decreasing agriculture yields, the plants will use even less CO2 and the concentration is going to go up even more. People will be more drowsy, will lose concentration and with it their ability to work, with serious economic consequences. IT”S WORSE THAN WE THOUGHT! The air we breathe will become toxic. I’ll bet this will seriously impact the ability of blood cells to swap out CO2 for O2, a major health challenge that will be a serious disaster. How many people are going to die? WHY DOESN’T ANYONE ON THIS BLOG CARE ABOUT THIS? DENIERS!

        /sarc

        https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms

      • “Bruce Cobb January 21, 2019 at 9:07 am
        co2 is a deadly gas, because if you breathe car exhaust for very long you’ll die
        we can pinpoint exactly what the climate is doing and will do, because of what our models driven by ginormous computers tell us, and unless we go back to living in dark mud huts and caves and eating twigs, we will kill the planet”

        Isn’t ignorance, gross assumptions and ‘argumentum ad ignorantiam’ great!
        If one is ignorant enough, specious claims are easy to spout.

        A) What is in car exhaust that kills you is carbon monoxide.
        Carbon monoxide monopolizes the oxygen receptors on blood cell hemoglobin, preventing oxygen from attaching.

        Which is why people die from carbon monoxide poisoning when CO reaches 50 parts per million. 0.005%. Higher levels of CO speeds up the CO poisoning rate.

        OSHA considers CO₂ safe at levels from 10,000 ppm to 30,000 ppm; i.e. 0.1% to 0.3%. Though higher levels have shown few ill effects.

        “Bruce Cobb January 21, 2019 at 9:07 am…
        models driven by ginormous computers tell us”

        Imagine that!? Models are omniscient!
        It does not matter to bruce that none of the models have produced anything near accurate results.

        “Bruce Cobb January 21, 2019 at 9:07 am…
        we will kill the planet”

        Another soft malthusian urbanite drinking kool-aid and forgetting to observe and think.

    • Huh!? Aren’t you the guy that is always telling us that climate science is settled? And now you are telling us that we do not know anything about agriculture? Isn’t agriculture a part of climate, I mean it largely happens outside. If we are are confused by agriculture and if agriculture is part of the climate then we are confused about climate.

      Overall I think the skeptically inclined are generally less confused as we are generally aware and admit to the things we do not know.

      Next you will be telling me that Corn or Potatoes are non-gmo. Hint these plants were only indigenous to the New World and the Natives Americans here spent thousands of year modifying them.

    • Steven,

      Both of your statements are true.

      One must acknowledge that our agricultural knowledge base is increasing at the most rapid rate in history. I believe that it is safe to say that we have learned more about plants in the past 100 years than we learned in the previous 10,000 years. We will always have much more to learn.

      The point of this article was that the NAS used only a portion of what we do know to be true about plants to paint a dismal picture which aligns with the authors’ odd agenda rather than the reality supported by empirical data.

    • Mosh,

      There is surely much that you don’t understand.

      However science does know that CO2 is essential for photosynthesis, the process by which plants make sugar, vital to their existence and the source of human food.

      More CO2 is better, up to 1300 ppm, after which not much gain in productivity occurs. Dave’s figure is a little high. The small bit of CO2 added by humanity has greened the planet. Tripling present plant food levels in the air would have an even greater beneficial effect.

      • More CO2 for instance has greened the Sahel, because plants there need to keep their stomata open for less time to get the food they require from the air. This means less water loss, so they can expand their range into drier areas.

        So far, more CO2 has been wholly beneficial. As early proponents of AGW like Arrhenius understood.

    • CO2 is a small percentage of the total atmosphere, but,
      CO2 is the major plant food, and
      whatever is in 2nd place is a trace fertilizer.

      • Trace but essential. Without CO2 in the air, then no land plants. Without land plants, no land animals or fungi. Nor many microbes.

    • The effect of trace gas increase on plants is KNOWN.
      The effect of trace gas increase on temperature is UNKNOWN.

      Moshe tries, but, as often, fails. Heh, we could say his pen, this time, is phony.
      =============

      • More heh, ditto on phony pens for Zeke, Kevin, and cetera(see Nic @ Judy’s). Really, moshe, you oughta be ashamed of yourself, joining the propagandists. Once upon a time, moshe, once upon a long gone passing.
        ================

  15. Are we really so certain that it is mankind’s efforts that have increased CO2 levels by 100 plus ppm as assumed in the excellent posting?

    I don’t have any great problem attributing a good part of the increase or even most of it to us but equally other natural factors could be at play and cannot be wholly discounted.

    • As sure as we can measure 282.9 ppm CO2 in ice from the year 1800 (that’s sarcasm BTW).

      As one that has measured CO2 analytically thousands of times, my opinion is that the accuracy of ice core measurements are biased and overstated. There has been no third party review of the methods even though the results are being relied upon to make multi-billion dollar decisions. Prior to the 1980’s, ice core measurements routinely showed 1000 ppm CO2 or more. What changed? Measurement methods were altered to give “more reasonable” results (just more fudge actually).

  16. It’s hard to get around increased productivity with increased CO2. So, what to do? I know. Let’s say that more CO2 makes crops less nutritious. link

    The thing is that greenhouse growers increase CO2 a lot and the nutrition value of their crops doesn’t suffer. Once again, academics demonstrate that they have no knowledge of the real world. They do, however, demonstrate a willingness to bend science to fit the CAGW narrative.

    • More H2O also makes crops less nutritious. For the same mass, more water content, so go figure. But no sane individual would claim that is better to grow crops in desserts, with no irrigations whatsoever, to avoid the ‘less nutritious’ crops.

    • Bingo. Exactly right, Bob.

      The alarmists’s fallback position, when shown proof of the benefits of CO2 fertilization, is typically, “but it makes food less nutritious.” But that claim is pretty obviously refuted by the example of food grown in greenhouses.

      Human activities (mostly fossil fuel use) have raised outdoor CO2 levels by about 130 ppmv, from about 280 ppmv to nearly 410 ppmv. By comparison, commercial greenhouses typically use CO2 generators to keep CO2 levels at 1200 to 1500 ppmv, which is an increase 6 to 9 times as great.

      If the modest increase in outdoor CO2 levels were making crops significantly less nutritious, then crops grown in greenhouses at dramatically higher CO2 levels would presumably be dramatically less nutritious than crops grown outdoors. But they aren’t, of course. Food grown in greenhouses at elevated CO2 levels has about the same nutritional value as food grown in open fields at ambient CO2 levels.

      I think the most prominent promoter of that claim is Dr. Irakli Loladze, a mathematician. He and I had an online debate of sorts, in the comments on Quora. If you’re not a Quora member I don’t think you ca read those comments, but I saved a copy here:

      https://sealevel.info/Is_Irakli_Loladze_right_that_rising_CO2_levels_are_affecting_the_nutritional_value_of_plants.html

      Faster-growing, more productive crops do require more nutrients per acre (though not more nutrients per unit of production). That is true both for macro-nutrients like nitrogen, and micro-nutrients like iron. Agricultural best practices include fertilizing according to the needs of the crops.

      The studies of nutritional content of crops grown with eCO2 (elevated CO2 level) have not found evidence that the overall nutritional value of crops is reduced by the improved plant productivity resulting from CO2 fertilization. Rather, they’ve found that when crops are grown in iron-poor or zinc-poor soil, the larger yields may contain lower levels (though not lower overall quantities!) of those micro-nutrients.

      Most studies do not find a net protein or micronutrient reduction due to CO2 fertilization, because the increase in growth rates is greater than the protein or micronutrient level reductions.

      The faster crops grow, the more nutrients they need. Competent farmers know that, and fertilize accordingly (or, for nitrogen, they may plant legumes — which, fortunately, benefit greatly from extra CO2). But if you fail to follow best agricultural practices, and don’t fertilize according to the needs of your crops, then the result may be substantial reductions in protein and/or micronutrient levels in the resulting crops.

      The cause of those reductions is not higher CO2 levels, the cause is poor agricultural practices. Adequate fertilization alleviates most or all of the reduction.

      Nitrogen is a special case. Inadequate nitrogen fertilization reduces protein production relative to carbohydrate production, because proteins contain nitrogen and carbohydrates don’t. Legumes, like clover, beans, and alfalfa, fix their own nitrogen, and with eCO2 they do so more rapidly, so adding extra nitrogen via fertilization is not typically required. (Fortuitously, those are precisely the crops which are most grown for protein!) Here’s a relevant paper:

      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773101/

      But for other crops additional nitrogen fertilization is often needed with eCO2.

      Here’s an excellent literature review on the topic, from the Idsos (as usual):

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

      Excerpt:

      “Rogers et al. (1996)… observed CO2-induced reductions in the protein concentration of flour derived from wheat plants growing at low soil nitrogen concentrations, no such reductions were evident when the soil nitrogen supply was increased to a higher rate of application. Hence, Pleijel et al. (1999) concluded that the oft-observed negative impact of atmospheric CO2 enrichment on grain protein concentration would probably be alleviated by higher applications of nitrogen fertilizers; and the study of Kimball et al. (2001) confirmed their hypothesis.”

      Here are some additional references:

      1. doi:10.1071/PP9960253

      2. doi:10.1016/s0167-8809(98)00185-6

      3. doi:10.1046/j.1469-8137.2001.00107.x

      • Once before on a WUWT thread I asked if anyone had data to detail the break down of different nutritional compounds for a human dietary plant grown which compared ambient CO2 & eCO2. I am asking for that again, please.

        On WUWT I once post data showing trace mineral content changes, amino aid proportional content & carbohydrate variability for a plant grown at eCO2. I can accept one’s perspective of what constitutes “nutritional” is open to interpretation & the phrasing as “overall nutritional value” gives the dismissal of eCO2 changes some cover. Before butressing one’s declarations by touting how greenhouses grow food humans can live on can we actually see the data on what “all” is in that food compared to field grown version?

        Repeated WUWT commentators over the years have stated if there is any reduction in nutrient in eCO2 grown food then we can just eat more of the more abundant eCO2 harvest – which I’ll accept is possible, for some, in some context. Whereas the suggestion farmers can simply fertilize crops better to counteract eCO2 induced nutritional changes I’ll concur is also possible, for some, in some context. However, most of my semi-arid farming neighbors are already cash strapped for buying fertilizer & local market forces are known to (sometimes) make your crop price at sale lower than the money invested.

        • I just do not see how the plant “knows” a CO2 molecule from an eCO2 molecule. It is like giving a human an oxygen mask sure there is increased uptake but the biological processes do not discriminate they just follow their chemical and biological kinetics.

          It becomes the plant’s new “is” paradigm. Obviously the genetic information already exists in the plant and those genes get switched on.

        • The question is difficult to answer. There is the soil depletion problem that makes field crops less nutritious than they used to be. link It could well be that properly grown greenhouse crops are more nutritious than field crops.

          There is a growing trend of indoor farming. All the light is artificial so it’s not the same as greenhouse growing. It could well be that standards will develop specifying the micronutrient content of indoor farmed crops.

          • The chart shows avg. increases of 4% sucrose, 13% glucose & 14% fructose, but decreases in protein & most minerals under eCO2. I don’t automatically equate this as positive nutritionally.

            Let’s, for sake of simplicity gaugeing the chart, that protein is 5% less under eCO2. If we follow someone’s advice to simply eat more (of the more abundant eCO2 harvest) then we are coincidentally going to be increasing already higher carbohydrate consumption.

            While I am not doing the math, that adaptation (eat more for protein) is going to alter the calorie intake. Since WUWT is not a nutritional blog & there are readers here with personal dietary orientation I am mentioning this without analysis.

            The chart shows “anti-oxidant”, etc. as much higher under eCO2. Again, to keep my comment from veering off topic, I will state (without analysis) that more of something (“anti-oxidants” as well) is not always better.

          • Did you bother to read the whole thing or just pick out what you wanted to and ignored the rest? It is called adaptation.

            .” And for those concerned about the decreases in protein, nitrate, magnesium, iron, and zinc that were also observed in the meta-analysis, these slight declines can be reduced, if not reversed, through the application of several management approaches that were investigated and discussed by the authors, including “(1) selecting vegetable species or cultivars that possess greater ability in carbon fixation and synthesis of required quality-related compounds; (2) optimizing other environmental factors (e.g., moderate CO2 concentrations, moderate light intensity, increased N availability, or increased fertilization of Fe or Zn) to promote carbon fixation and nutrient uptake interactively when growing plants under elevated CO2; (3) harvesting vegetable products earlier in cases of over maturity and reduced benefit of elevated CO2 to vegetative growth; and (4) combining elevated CO2 with mild environmental stress (e.g., ultraviolet-B radiation or salinity) in instances when this enhances vegetable quality and might counteract the dilution effect or direct metabolic pathways toward the synthesis of health-beneficial compounds.”

            All in all, it would therefore appear that CO2-induced plant nutritional enhancements far outweigh any CO2-induced plant nutritional declines. Thus, it can reasonably be concluded that rising atmospheric CO2 concentrations will yield future health benefits to both human and animal plant consumers.

          • Hi Robert, – I appreciate your highlighting what intrigued you. I simply used your link’s chart for average changes in nutritional components to avoid confusion.

            As for your point “1)”: hey, that’s great – select the best plant. According to existing trends (linked chart) the “best” plant probably is still going to be carbohydrate increased, protein decreased & lower in many minerals. Without the specific cultivar of a specific plant’s nutritional data I won’t try to guess how much less carbohydrate, more protein & greater minerals can be gotten growing at eCO2.

            By the way, it has been the cultivar selection, which , among other things (agronomic science) that has driven some of the yield increases the O.P. discussed & did not parse from yield increase that was CO2 related. Meaning rising CO2, currently, is only a contributing factor.

            As for your point “2)”: nice tactics – most of my farming (small landholders) neighbors don’t have ready available funds for agricultural inputs (ex: lots of nitrogen) & they field crop (no light or CO2 greenhouse environmental control). My region is semi-arid & the topic of the day is always about rain; so I personally am 100% willing to see eCO2 (for plant water use efficiency, if nothing else).

            As for your point “3)”: harvesting earlier sounds like something suitable for greenhouse vegetables that can be quickly picked, hydro-cooled, shipped to a refrigerated packing house, treated to conserve (ex: cut down ethylene & pectinase activity) for trans-shipment & await customers in an air conditioned supermarket.

            My “developing country” farm neighbors choose to pick their cash crops when the season’s conditions are suitable (we get 1 rainy season & usually a very “short” rainy month plus unscheduled rain year round) & the produce item has market appeal (ex: no customers for dinky little okra, nor for jumbo okra). Family farms in “developing” countries don’t have crop insurance; sometimes here in Gringolandia a crop will be pre-sold (milk, incidentally, is very frequently pre-sold against money borrowed from a cheese producer) but this (pre-selling) is usually for things like coffee & cacao (not perishable vegetables). I’ve seen cases when mature crops were left in the field because following up paying the harvest labor & transport to market would have made grower lose money.

            As for your point “4)”: manipulating UV-B is a again, a greenhouse option only. Manipulating “stress” is a more complex issue (I’ll skip agronomy explanation) & although some tactic(s) for this may (as in theoretically being possible) be a put into practise for field crops the practical execution (of any specific stress & subsequent seasons’ consequences) is somewhat of a challenge.

            I can see eCO2 greenhouses being able to manipulate “stress”, although I am not sure if this will actually increase protein yield, or alter the amino acid profile in proportions we humans might “nutritionally” prefer. Possibly the eCO2 carbohydrate increase may decrease as carbon used to produce stress response molecules; although then too, it (carbohydrate composition change) may depend on which stress exposure employed.

            Personally, I am of the opinion that experimental eCO2 is good science & I make a big deal only about how we need to understand that not all results are lineal. Based on how long it will take for field crop CO2 levels to reach experimental eCO2 levels my thinking is that plant science will develop faster in terms of boosting yields for C3 crops of commercial value (which does not mean automatically more “nutritious” either).

          • Getting the necessary information to farmers is the responsible of the government and it is in the industry’ Interest to also see that farmers have the most uptodate information. I have farmers in my family and have worked on a couple of farms in my younger days. I always found that farmers will not wait for the government to supply them with the necessary information to improve their farms. Several of my relatives made sure that their offspring went to college first then came back to the farm.

          • Again Robert, – I have no doubt your developed countries have farming depth such as you elucidated. My work has been in “developing/under developed” countries over the decades which on several continents & assorted agricultural focus – I’ll lump it together as agro-industrial.

            20 years ago I had a tropical based import- export business. I mostly (among other food related items) imported pallets of agricultural seeds from the USA & mostly exported shipping containers of bananas (among other unprocessed foods) to Europe.

            Which is to say the circumstances of our tropical market, farmer finances, crop issues, cultural proclivities & post-harvest peculiarities are clearly known to me. I’ll try to give an example that makes me assert our discussed points “2), 3)& 4) are irrelevant in my adopted “developing country” unless the small farmers can have greenhouses essentially given to them (hey, I’ve seen this happen to a few).

            Scenario:
            eCO2 has produced crops with more carbohydrates, less protein & less of many minerals. I have a license to import specially bred seeds from USA that reverse that pattern.
            I initiate an educational out-reach to spread the science supporting the special seeds & try to get adoptees.
            Being special seeds they cost more than other seeds & growers do their own price comparison.
            Then most of the small farmers look at their finances & buy the old kind of seeds that yield produce with more carbohydrates & lower protein.
            I remonstrate trying to convey the difference these small farmers are giving up & they negate this by declaring their volume of sales are to customers whose factor for produce selection is price & cultural preferences (type of bean/cucumber/greens/grain/etc.).
            Some do take my advice on special seeds, but sales are anemic. With a stockpile of special seeds the import venture isn’t lucrative.
            The following year instead of pallets imported few special seeds are brought in to service any farmers who trialed the 1st batch. This makes the
            price higher by not being a bulk importation.
            Appraised of a higher price & with financial details on their rate of return the early adopters consult their peers still growing non-special seeds. Imported seed sale volume goes down.
            Losing money (& customers) is what I can envision likely happening on this import scenario, more so than widespread adoption supporting my business
            model.
            So I go to the government agricultural agencies & explain the scientific parameters. My contacts tell me they’ll see what they can do. When we get together again I’m told budgets are tight with other agricultural priorities than special seeds from abroad.
            I give up the import license the following year by not paying relevant fees after my contacts submit my grant proposals to assorted NGOs, which pass on funding.
            One NGO offers up instead a grant for a packing house in Afghanistan. I say “no thanks, like I told you with that offer for an agricultural project there back in 2005 – Afghanistan isn’t for me.”

          • Correct me if I’m wrong, but I think that most crops which are eaten for protein are legumes, which fix their own nitrogen, and don’t suffer substantially reduced protein content from eCO2.

            Wheat is a bit of an exception, because high gluten content (a protein) is prized, for bread-making.

          • Fig 2 has variable chart of soybeans’ (have nitrogen fixers at roots) decrease in protein under eCO2.See free full text available on-line : “Effects of elevared CO2 on the protein content of food crops a neta-analysis.”

            It shows again, how depending on the experimental parameters eCO2 is hard to make definative declarations about. Optimally retractors & advocates should qualify their writing when it is actually a generalization, but that makes for dense reading.

  17. SAVE THE PLANET!
    EMIT CO2

    (I have never done bumper stickers on my car, but I am ordering this one.)

  18. There’s another beneficial factor. If you to plant earlier, then your growing season will be closer to the summer solstice and you’ll gain some from higher sun and longer days. At high latitudes, this can get significant.

    In some cases, global warming can extend the growing season enough to allow growing crops that weren’t even possible before.

    • True, but it is true for any growing season, up to the point that the plant (which is generally an annual) gains nothing from longer growth and more sunlight.

  19. “So +4°C of warming is equivalent to planting about 24 days late.”

    Wouldn’t that be 24 days earlier?

    • Not based on their theory, planting earlier gives you better yields as you plant cultivars that have a longer growth period prior to harvest (up to a point). Of course, they are still wrong because farmers will plant the right cultivar. This article makes unrealistic assumptions that would require farmers to use seeds not acclimated to the new climate

  20. Climate-killing CO2 supports the “white man bad” narrative, so it’s not going to go away easily.

  21. It really is utterly appalling that the Climate McScientists and their tame hacks in the MSM get away with this time after time. They ought to be held to account for propagating disinformation and trying to frighten people with nonsense.

  22. Why doesn’t the massive increase in plant growth (natural and crops) show up as a dropping or stabilizing of the CO2 levels. Is there any science about how much CO2 all the extra growth is soaking up? Is it less than we are putting out ? If plants evolved to grown in high CO2 levels, then they should be soaking up all of the CO2 we are emitting.

    • It does, if you measure CO2 in a cornfield during active growth when there is no wind. The levels drop very low. The wind is needed to distribute the CO2 generated elsewhere to the field.

      The same effect is present in a greenhouse. CO2 levels drop precipitously at the beginning of the day’s growth, to levels that will not support photosynthesis. The growers add CO2 to maintain their desired level.

      • Yes, but that wasnt his question. The question isnt whether plants use CO2 to grow, they do. His question was about the carbon cycle, which is much more complex. It seems our cutting down tropical forests is offsetting the greater CO2 growth of other forests.

        • According to NASA, the planet as a whole is getting greener.
          The cutting down of the tropical forests for the most part is at a constant rate. One part being cut down, another part growing back. It’s not as dire as some want us to believe.

          • I dont disagree, but I am not sure you are talking about the question asked. Try reading the reference and get back to me.

          • I addressed the claim that cutting down tropical forests was offsetting greater CO2 growth of other forests.
            If you meant something else, you should have written something else.

  23. BTW, in addition to the hilarity of any historical graph of crop yields vs temps, note that while about 1/3 of the Earth is too cold for serious biomass generation at any given time, there is no place on Earth too hot for agriculture given sufficient irrigation.

  24. I have a theory that Gaia was concerned about falling carbon dioxide levels, as they were getting near to the level where plants can no longer survive. So, she evolved humans, because that species is exceptionally good at drilling holes in the ground to release the sequestered CO2 from bygone ages.

    However, if we stopped releasing CO2 before optimum levels are reached, and started covering the planet with spinning thingys instead, she might just decide we were a mistake and try another species.

  25. I am a qualified and experienced science with a background in environmental research, agriculture, and geology (yes, geologist must also look at facts). The article is correct. Wrongly thought most people understood the facts and easily observed relationship of ag production .

  26. It’s political science as we know. Doesn’t stop farm state politicians in the US from driving this narrative to get increased funding. Climate Change crop insurance, Climate Change mitigation money, A John Deere tractor that runs on ethanol, whatever. For some it’s the money for others its the control. The green thing is useful for many reasons. Foe the NAS it’s “science funding” from the plebs pockets.

    This feature makes the green hydra hard to stop.

  27. Note: There are several different kinds of photosynthesis. Plants that use “C3” or “CAM” photosynthesis benefit the most from higher CO2 levels. “C4” crops benefit the least, but even C4 crops benefit when under drought stress. Most crops use C3 photosynthesis. There are only four important C4 crops, all of them grasses: corn [maize], sugarcane, sorghum, and millet.)

    You have this backwards, C4 and CAM plants benefit the most, they are evolutionary changes which allow these plants to grow better in hot, dry conditions than do C3 plants. Photosynthetic rate for C3 plants is better than C4 at temperatures below 20ºC whereas C4 does better above 20ºC.
    Most crops are C3, focussing on a C4 (maize) is misleading.

    • Well, kinda sorta. C4 plants evolved in low CO2 conditions to make their photosynthesis more efficient under these conditions. They also are better at tolerating heat. SO – it depends – for heat C4 are better, for high CO2, C3 are better. This stuff is complex….in fact many specualte that we are at a CO2 level now where C4 plants do not have a growth advantage as they cannot take advantage of the higher CO2 present today.

      Also, he is correct to focus on maize, it is the biggest crop grown on the planet and accounts for a large part of the calories available to humanity.

      • It is a very Good Thing that the C4 plants are mostly grasses, and there are no C4 trees. Trees have the potential to sequester carbon for a long time. Grasses mostly rot and release their CO2 within a year or two.

        Widespread C4 trees could potentially suck so much of the remaining CO2 from the air, and drive the CO2 level so low, that it would kill off the CO2-starved C3 plants.

        • So, are the findings in this write-up able to be published to the Proceedings of the NAS for scientific method review and scrutiny?

  28. David,
    Thanks for the well written and well documented article refuting recent fabrications concerning the evils of CO2 and food growth..
    It is nice to know that everything we were taught in grade school about CO2 and photosynthesis was spot on.

  29. Tree picture use is misleading. It is an age phase without reference to mature trees & there are lots of differences among kinds of trees.

    Elevated eCO2 induces more roots, especially fine roots (usually). Trees with deeper fine roots access more nitrogen from fallen leaf litter (identified as isotope 15N) that was/is 30-60cm down.

    Analysis of a variety (C3& C4 included) 28 plants reveal that in 6 species eCO2 was associated with no change in their leaf 15N, in 3 species eCO2 was associated with an increase in their leaf 15N & in the majority (19 species) eCO2 was associated with a decrease in their leaf 15N.

    Trees unlike row & geenhouse crops) are needing leaf nitrogen (quantifiable as 15N) cycling for uptake. A long term eCO2 (USA gum tree) analysis showed that over time the pool of 15N goes down.

    My point here is that this decreasing change in nitrogen available for trees makes the above tree picture of eCO2 impact on young growth a snap-shot in time that is not indicative of future productivity. To be precise, I will add that the decreased pool of nitrogen for a tree takes years to
    develop into a significant limiting factor.

    Plants have different reactions to eCO2. For example, if there is an association with the type of fungi myco-rrhizal then more roots (from eCO2) foster more of this fungi & then those fungi (avg. 6% nitrogen) themselves are using more of the soil nitrogen.

    The exceptional impact of eCO2 on many kinds of adult trees is less than what might be extrapolated from the above photo (water will become more relevant to mature trees). The eCO2 will be putting more nitrogen in woody mass & more nitrogen assimilated will go into the roots under eCO2 than otherwise.

    • All trees are C3, so I expect that they all benefit from eCO2, though to varying degrees. This F.A.C.E. study examined birch, aspen & maple:

      https://news.umich.edu/future-forests-may-soak-up-more-carbon-dioxide-than-previously-believed-helping-to-buffer-climate-change/

      But, like everyone’s favorite Facebook relationship status, “it’s complicated.” For instance, I’ve recently learned, to my surprise, that alder trees fix their own nitrogen, via symbiotic bacteria, like legumes do.

    • Original Post asserts eCO2 results in the “… plants healthier.” That may be an over-statement.

      C3 plants respond to ratio of CO2 to O2 (RuBP, ribulose bi-phosphate “acceptor” molecule takes these catalyzed by enzyme Rubisco). And at the same temperature different plants will bind different ratios of CO2 to O2; this dynamic applies to both C3 & C4 plants & can partly contribute to variable results reported in eCO2 experiments.

      When C3 plants (named because CO2 + Rubisco acting –> two molecules having 3 carbon atoms in them) take up O2 (instead of CO2) the C3 plant’s Rubisco catalyzes instead only one molecule having 1 carbon in it plus phospho-glycolate (ie: O2 + Rubisco acting –> phospho-glycolate + a single carbon molecule).

      Now, eCO2 for C3 plants causes (the pressure of CO2 relatively reduces O2 processing) less of phospho-glycolate being made & more of air’s carbon (from CO2) taken into the leaf in a form readily assimilated. Which we observe as more (usually) plant matter under eCO2.

      My issue with eCO2 and plant “health” claim is that oxygen O2 processing is not a waste of time. The single carbon molecule is used for synthesis of the amino acid methionine, purine & pyimid-ines. The phospho-glycolate made in chloroplasts gets sent out for plant purposes.

      In light the O2 + Rubisco generated phospho-glycolate pathway (glycolate pathway) involving the leaf mitochondria. Simply stated there is a release of CO2 from the mitochindria plus release of nitrogen NH3 nitrate.

      This mitochondrial CO2 release is called “photo-respiration” . Along the way, during photo-respiration, assimilated carbon (CO2 taken in & “fixed” w/Rubisco) is getting used for other things than making “sugar”.

      Because eCO2 reduces O2 processing eCO2 reduces”photo-respiration” & we see the growth boost of eCO2. On average the way plants handle carbon & nitrogen as a result of “photo-respiration” uses up over 30% of available energy.

      And also due to “photo-respiration” about 25% of the newly assimilated carbon (from CO2) is gone (when glycolate pathway uses 2 glycine molecules comprising 4 carbon atoms to make a serine). There is fortunately 75% of carbon involved in “photo-respiration” that eventually gets shunted back to chloroplasts as 3-carbon molecules (just like the 3-carbon molecules made by “fixing” CO2).

      I’ll continue …

      • “Photo-respiration” orientation now put forth I”ll try to describe plant health. Plant mitochondria will take glycine derived from phospho-glycolate (photo-respiration product) via a pathway (glycolate pathway) & the mitochondria will “oxidize”/”burn” glycine. Thus leaves are relatively low in glycine under ambient CO2 since glycine & serine are precursor molecules of chlorophyll – so eCO2 plants can be seen by our eyes as “greener” (to be precise there are 3 ways leaves can make glycine)

        Leaves that get nitrogen taken in as nitrate NO3 (plus 2 H+ via enzyme nitrate reductase to –> H20 plus nitrite NO2, which with 6 electrons plus 7 H+ via enzyme nitrite reductase to –> NH3 ammonia nitrogen) will change that into nitrogen NH3 ammonia,; because leaves can only make amino acids from NH3 ammonia (& NH4 ammonium). Thus “photo-repiration” release of NH3 ammonia by mitochondria benefits the leaves by, not only providing more amino acid ready synthesizable nitrogen as NH3 & by obtaining that NH3 nitogen without requiring many H+ ions &/or electrons there are more of those free to process NO3 nitrogen taken in.

        One way the “health” of eCO2 plants has been reported as being vulnerable beause their leaves have altered carbon (more) ratio to nitrogen (less under eCO2). This is a trade off that has been the subject of prior WUWT posts so I’ll forgo revisiting the dynamics.

        eCO2 assimilation when (light adequate) produces more “sugar”; thus, the leaves are a “source” of carbon for use. The leaf (mesophyll) loads up with “sugar” (sucrose & fructan/”fructose”) so “sugar” is shifted toward the leaf bundle sheath (cell layer around leaf’s veins).

        C3 bundle sheath holds CO2 assimilated “sugar” until it can divest it (“sugar”) into the vascular phloem for the assimilates to be delivered to a plant “sink”. We see eCO2 growth resulting in more roots (“sink”), more stem/trunk (“sink”) & more dry matter (& lignin).

        The “sugar” enriched C3 plant’s bundle sheath (technically a layer of parenchyma cells) from eCO2 makes it vulnerable (less “healthy”) to certain kinds of insect feeding. Then too when the roots &/or lower stem of a plant (“sink”) is cooled the bundle sheath retains more “sugar”.

        To load “sugar” into the phloem for circulation O2 is required (even though bundle cells have more CO2 than O2) by both C3 & C4 plants; the difference is that C4 plants must use O2 “evolved” as part of photo-synthesis (“fixing” CO2). Thus when it is dark/cloudy/night the C4 plants’ rate of phloem loading (“sugar”) is reduced heading for a “sink” & their C4 leaves are more attractive to insects.

        To be precise for C4 plants: low ambient CO2, due to less photsynthesis generated O2 (more photo-respiration), can also be said to result in less “sugar” loading into the phloem for distribution. Thus (C4’s want of properly provided O2) assures insects can also find attractive “sugar” in leaves – just at a lower amount of “sugar”.

        I have tried to write for laymen & end with pointing out that C4 plant’s concentrate CO2 in bundle sheaths for better photosynthesis efficiency under low CO2 (it decreases CO2 exported from mitochondria as “photo-respiration” in the light). There is a theory that when Earth’s air had low CO2 (high O2) plants evolved moving their enzyme (glycine de-carboxyl-ate) that is integral to getting glycine usable into the bundle sheath (C3 plants did/does this in their mesophyll).

          • Hi Dave Burton, – I took the time to get some things in print for people like you who are dealing with aspects of CO2 to mull over at leisure. When reading it skip over what is in parenthesis (that’s for those who want to look up things by name) to weed out distractions. Laymen hear some commentators/sources using words like photo-respiration & I wanted to try to describe what that is about.

            You link a picture of rice at variable levels of CO2 & ask which is thriving. I mentioned that “health” is relative to insect predation: at eCO2 the ratio of carbon goes up relative to nitrogen & commonly (not always) chewing insects with eat more of the plant to get more nitrogen –> that plant can get a lot of damage.

            Rice has a juice sucking leaf hopper that likes to feed on it. At eCO2 & common ambient temperature the leaf hopper will eat & put out more of a substance called “honeydew” (than at ambient CO2).

            “Honeydew” is sticky sweet & very prone to be colonized by mold. So the young pictured rice plant at eCO2 can end up with it’s leaves massively covered in black mold (see pictures of “sooty mold” on-line) which cut down photosynthesis.

            Now ambient CO2 & ambient temperature growing rice still can get some leaf hoppers’ honeydew,but it will be less than eCO2 & ambient temperature. In fact eCO2 & elevated temperature growing rice will also get less honeydew than eCO2 & ambient temperature, but: the female rice leaf hopper will lay more eggs.

            We humans can be robust looking & yet suffer more pathology than others that do not seem to be “thriving”. And then too, one may have a problem that confers better outcome than otherwise; the aphorism is “looks can be decieving.”

            By the way, I have no qualms about eCO2; greenhouses can certainly do nicely with adding CO2. Pictures are informative & I just think additional context is relevant.

          • I am pro-GM. And I’ve certainly inadvertently taken in lots of agricultural chemicals over the years too. I’m pro-fungicide/herbicide – ideally properly administered.

  30. Steven Mosher January 21, 2019 at 7:26 am
    co2 is a trace gas.
    there is so much about agriculture and plants we dont understand.

    So according to Mr Mosher CO2 is the sole climate control knob. A few ppm increase will cause global destruction. But for plant growth it is a trace gas and its effects are unknown.

    Can this be the same CO2 and the same Steven Mosher.

  31. If we relied on these academics to grow the crops we depend on, I’m sure their output would be in line with their gloomy predictions. Fortunately the average farmer doesn’t have their educational background, so yields have been increasing.

  32. Corn is a high altitude, tropical plant. Ancient Mexican farmers developed it from its genetically identical (same protein coding sequences, ie genes) wild ancestor, teosinte. The key mutations exploited by breeders are in control sequences.

  33. Some “experts” said that with higher levels of CO2 plants grow more rapidly and have less protein.
    My response was not all and you can add nutrients as required,

    • You solve this by using the increased fertility to grow more fodder and eat more beef and pork.

      Which is exactly what the chinese have been doing this last generation. The first time I visited Beijing back in the early eighties there was only about a dozen restaurants serving Beijing duck, now there are many hundreds, if not thousands.

  34. The first map [Figure 1. 2018 Corn yield . . . ] should be looked at along with the 2nd one down from it – where Iowa (18) is shown in green.
    On the two maps, note {map #1} the fully colored Great State of Washington, now the number one producer of Blueberries.

    The first map shows WA with 210 bu/acre, but there is a central-regional area shown on the 2nd map. The area where corn is grown is also irrigated. This is a naturally hot and dry area in the summer. Note comment by TallDave @8:31, a few above this one.
    Note also that the 210 bushels is the highest state average!

    Each year there is a contest:
    National Corn Growers Association 2018 National Corn Yield Contest. 477.68 bushels per acre

    The 477 bu/acre was grown in south central Michigan with irrigation. A North Dakota grower managed to get 299.78 bu/acre with non-irrigation.
    There are 18 winners (3 each in 6 categories).

  35. David Burton writes:

    Most plants grow best with daytime atmospheric CO2 of at least about 1500 ppmv. That’s about what CO2 levels are thought to have averaged during the Cretaceous. It’s 1090 ppmv higher than the current average outdoor level of about 410 ppmv.

    “YUP”, and plants were growing their best during the (Mesozoic) Triassic, Jurassic and Cretaceous Periods because of the high atmospheric CO2 ppm and warm global average temperatures as defined on this graph of geologic periods, to wit: http://worldview3.50webs.com/6temp.chart.n.co2.jpg

    And according to the above cited graph, atmospheric CO2 abruptly increased to about 1,900 ppm at 259 mya (Triassic Period), …… and then increased to 2,800 ppm at 150 mya (Jurassic Period), and then began a gradual decline to 700 ppm at 66 mya (Cretaceous Period).

    And the reason we know that plants were growing their best during the Mesozoic Period is because of the interesting scientific fact associated with the above “rise n’ fall” of atmospheric CO2 from 1,900 ppm @ 259 mya to 700 ppm @ 66 mya …… is that it correlates directly with The Age of the Dinosaurs, to wit:

    During the Mesozoic, or “Middle Life” Era, life diversified rapidly and giant reptiles, dinosaurs and other monstrous beasts roamed the Earth. The period, which spans from about 252 million years ago to about 66 million years ago, was also known as the age of reptiles or the age of dinosaurs.

    Tremendous amounts of rapidly growing “green” biomass was absolutely necessary for the evolution and survival of the dinosaurs and when atmospheric CO2 started its decline during the Cretaceous, so did the decline of the dinosaurs and their demise was complete when CO2 fell below 700 ppm @ 66 mya.

    Thus it was “atmospheric CO2 sequestration” by natural processes that SLOWLY “wiped out” the dinosaurs (their death was due to starvation), …. not a sudden event such as an asteroid strike or some other silly suggested cataclysmic event.

    • So you mean it was purely coincidental that all non-avian dinosaurs, most avian dinosaurs, most mammals, all ammonites, all mosasaurs, plesiosaurs and pterosaurs, and a lot of other all’s and most’s happened to go extinct 66 mya, at the exact time that the Chicxulub impact happened?

      • tty, given the accepted scientific fact that all the major animal phyla that exists today, ……. evolved during Cambrian Explosion (521 mya), ….. please tell me what you think was so “MAGICAL” about the, per se, Chicxulub impact event of 66 mya that primarily targeted the extinction of the extremely large herbivores dinosaurs and their meat-eating predator dinosaurs but spared the ancestors of all current day phyla and species?

        Deny this, to wit:

        By the end of the Cretaceous 15 mammal families were in existence that we know about. The end of the Cretaceous (66 mya) however saw another mass extinction. Though scientists are still unsure as to its causes, it is known that this K-T event, as it is known, resulted in the complete extinction of the dinosaurs. It also saw the death of all the Pterosaurs, the flying reptiles. All these species dying out left huge niche vacancies in the habitat. Following this disaster it was the mammals alone of the remaining groups of animals who diversified to take advantage of this new situation.https://www.earthlife.net/mammals/evolution.html

        • And ps, tty, where it states in the above that “All these species dying out ”, ….. what it actually means is ….. “they disappeared from the fossil record” …… and not that they instantly died/disappeared.

  36. The only place where NAS is fully stated is under the 4 photos of the pine tree. Even there the letters and name are not connected. This is a dis-service to readers.

  37. In addition to fertilization, CO2 increases water efficiency of plants and makes water more available for other plants and increases soil moisture. Increases carb production also allows many plants to share more resources with symbiotic bacteria and fungi which increase bio available Phosphorus and Nitrogen and add carbon to soil, making it more structurally sound and capable of retaining water. Reality is that N & P are CO2 constrained and this will increases retention of water over land and accelerate CO2 uptake as CO2 rises. This is likely already mitigating sea level rise, as GRACE shows significantly more retention of water over than hydrological models estimate. https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511

    Crops, particularly C4, have been engineered to optimize for carb production and are generally not P & N constrained, so this happens to a lesser extent with industrialized agriculture.

  38. I’m with Scott Adams on this:

    Facts don’t matter.

    When an AGENDA is the driver, then science takes a back seat. Feelings are what counts and when you argue with someone with an agenda, be prepared never to win. Science be dammed, especially YOUR science as it is either lies to support your cause or made-up for the purpose of “confusing” me. This is what I have noticed and facts don’t really matter. Look at all the science that supports natural variability and how easily it is dismissed by those claiming to be scientists. Facts don’t matter.

    When someone cites science and argues Global Warming is happening beyond what the current crop of legitimate scientists argue, be prepared to be attacked and called a “den1er”.

    I have given up on the thought of ever winning an argument when faced with someone with an agenda.

    What folks need to do I suppose is minimize the “facts” and concentrate on the basic issue of AGENDA.

      • My comment would be to not engage them as they are agenda driven.

        It does no good. You will never win in a legitimate debate. It involves “feelings”. Religious zealots are about “feelings”. It makes them feel good to behave that way and they feel morally superior.

        Work on other more salvageable people with little agenda to protect.

      • Derg, you’re dealing with people driven by emotion, so you probably need to appeal to their emotions. I suggest talking about the Third Horseman of the Apocalypse: famine.

        https://sealevel.info/Apocalypse_vasnetsov-Four_Horsemen_of_the_Apocalypse_famine04.png

        If you’re talking to someone old enough to remember frequent major famines, in places like Bangladesh, then remind them of that, and ask them if they’ve noticed how infrequently we hear about famines, now? Inform them that Bangladesh and India now struggle with the problem of chronic food gluts!

        If you’re talking to a youngster, then you must first teach him or her about famines. Throughout history, famine has always been one of the great scourges of humanity — until now.

        Here’s a paper, about the great drought & famine of 1875-78, which shows how famines used to happen. I wouldn’t put too much stock in the attribution part, but the history is illuminating:

        https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0159.1

        A reasonable estimate is that the rise in CO2 levels is responsible for a global increase in agricultural productivity of about 20%. That is a Very Big Deal. Ending famines is an advance comparable to ending war, and rising CO2 levels have contributed substantially.

        If the person you’re talking to is the sort who gets all dewy-eyed about rain forests, you could also mention that if we didn’t have the extra agricultural productivity — i.e., if CO2 levels were still at 280 ppmv — then we could approximately make up for the loss of productivity by converting all of the world’s rainforests to agriculture.

        • Dave Burton – January 21, 2019 at 5:14 pm

          Derg – January 21, 2019 at 3:14 pm
          —– how do you win an argument with religious zealots?

          [Dave B] “Derg, you’re dealing with people driven by emotion, so you probably need to appeal to their emotions.

          Personally, me thinks if the “appeal to their emotions” ….. was a request, …. it would be denied.

          And if the “appeal to their emotions” ….. was for a reversal of their belief, ….. they would just become more convinced they were correct.

          One way to win an argument with a religious zealot is to use their own commentary or beliefs to embarrass them “in front of gawd and everyone”, ….. which is sure to cause them “severe emotional pain”, …….. which is not easily forgotten, if ever.

          And that is because the stimuli that triggered the “pain”, be it mental or physical, is quickly nurtured (learned), easily recalled and excites an emotional reaction again. As per the saying “hell hath no fury like ……”

    • You honestly can’t expect an English major to write in English. Fer reals, dude.

      He blames the poor formatting and spelling on his “smart” phone.

  39. From the Johnson CO2 generator ad:

    Nighttime levels in a greenhouse range from 400 to 500 ppm due to plant respiration. Shortly after sunrise this level will drop to normal atmosphere (300 ppm) due to the plant using the early light to start photosynthesis. After 3 to 4 hours of early morning sunlight the CO2 level can drop to around l00 to 150 ppm, then growth is practically stopped. Supplemental CO2 added during this period can substantially increase your plant and flower production.

  40. I enjoyed this scholarly article, Dave Burton. The “Great Greening” of the planet is the only unequivocal anthropo-assisted Climate Change that has occurred thus far. Temperature rising from the LIA (thank goodness for that) was a natural effect, like the MWP before it when Greenlanders were growing grain and other crops for a period of about 400yrs.

    Note that this big greening took the clime syndicate by surprise and it is their deepest anxiety because of what it does to the real cost- benefit equation for CO2 increase. They know if they don’t hold the line on this, the whole game is over. This is why they only talk about exaggerated temperature rise and what it will do to crops. Ive seen articles on forest development and crops that attribute changes only to temperature rise. Sometimes they grudgingly feel obliged to admit a small contribution of CO2, but they then beat it to death because “it’s only temporary” and it will result in even more CO2 loading the atmosphere when the brief honeymoon is over. “The Great Greening” is poised to strike the final blow to this terrible movement that has been basically on a life support coma since struck by the one-two punch of a 2-decade “Dreaded Pause”that caused the Climate Blues epidemic and Climategate that exposed the underbelly of the beast.

    • Quote Gary Pearse:
      “….is the only unequivocal anthropo-assisted Climate Change that has occurred….”

      Not even sure that is true. Neither the geochemical, geophysics or biological processes discriminate as to which CO2 to use. So, logically some of the human release CO2 has been returned to a sink. And if the Earth is naturally Warming, regardless of our actions, then there is just more CO2 in the atmosphere. I have seen some of the math and thoughts behind the math but coming from my chemistry background equilibrium is in play. Models are not reality, they are tools and perhaps poor tools.

      But hey maybe Monsanto has taught the corn to sink only the human portion of CO2…perhaps my body is only using the natural sources of CO2. Or perhaps it using trans-dimensional CO2 to keep me Social Justicily honest ; -)

  41. Wanna see something funny?
    Make a graph showing temps since 1980, and on the same graph plot crop yields for the major grains.
    Do this for the US, the globe, anywhere.
    Laugh, share, rinse, repeat.

  42. Dave: It is worth keeping in mind that plants can’t open their stomata and feed on CO2 from the air without losing water out those same stomata. Water is as essential as CO2, a source of nitrogen, phosphorus, potassium, and some micronutrients. So, if you specify adequate natural rainfall or irrigation, I reasonably content accepting that more CO2 will mean more plant growth despite more warmth.

    However, in the Western half of the US, the supply of water is limited. More than 90% of the water flowing in the Colorado is piped somewhere. The water that filled Owens lake is shipped to LA. San Diego is building a huge desalination plant. The water level in aquifers is falling, especially the big aquifer under the High Plains and in CA during the drought. Precipitation is supposed to rise about 2%/K globally, mostly at higher latitudes. The rate of evaporation varies with saturation vapor pressure (which rises 7%/K), undersaturation (1-RH), and wind speed. So global warming is expected to make land drier. CO2 fertilization is only part of the story. Water is another important part of the story, plants can’t breath in CO2 without it. Stomata stay closed under water stress.

    I won’t venture to try to balance these opposing factors. However, it seems to me that we SHOULD be able to use our water more effectively, but water-rights in the West are like guns to NRA members. It also seems to me the better crops especially through genetic engineering could be a big help.

    • Plants produce fewer and smaller stomata as a result of higher concentrations of carbon dioxide. This reduces their water use. Arid regions are greening as a result of this happening.

      • Robert: Thanks for the reply. If you look at Figure 1 and 3 in the linked paper, you will see that greening is concentrated in regions with plenty of rainfall. The Western US and Australia not showing much, if any, greening. Standard measures of drought include the effects of both reduced precipitation and increased temperature, because of increased transpiration. There is nothing special about CO2 and stomata: When CO2 is entering, water is exiting. Higher CO2 means fewer water molecules lost per CO2 taken up (higher efficiency). But that efficiency will be needed because drought stress will be more prevalent. Stressed plants shut their stomata and postpone growth until conditions are more favorable.

        http://www.creaf.uab.es/Global-Ecology/Pdfs_UEG/2016_Zhu_et%20al_Nat%20Climate%20Change_2016.pdf

        • https://m.phys.org/news/2013-07-greening-co2.html
          The deserts are greening as a result of increasing levels of carbon dioxide. Since there is no evidence of increasing droughts this means that plants will be able to increase their cover of arid regions. The map on this link shows that this is happening. As a result of increased plant growth the soil will be better able to retain moisture improving even more their ability to encroach into arid regions.

          • Robert: Thanks for the reply. The link you sent to greening of the deserts is a press release associated with the same journal article I provided you. However, the map in your press release looks nothing like the maps in the original paper. I finally found the map in your article as Figure S12 in the supplemental material and it explains the confusion. The authors used climate models and other information to ATTRIBUTE greening to different factors: CO2 fertilization, change in precipitation, nitrogen fertilization, (climate change) warmer temperature etc. The map in your article is the greening ATTRIBUTED to CO2 fertilization. It is the output of a model. On Figure 11, you can see the “browning” ATTRIBUTED CO2-induced warming and increased water stress in Australia and the Western US. The OBSERVATIONS show much less greening in Australia and the Western US than elsewhere.

          • Frank, I do not believe that I ever argued that arid regions were greening more than other areas. Just that some of the greening taking place in these areas could be attributed to increased levels of carbon dioxide. While models were used they were used to help determine the extent to which these other factors were contributing to the greening. I believe that our understanding of these factors is sufficient for a reasonable estimation of their effects to be modeled. These increases in carbon dioxide would allow plants to take in more carbon dioxide without losing more water. They do not have to open as much nor to open longer for additional carbon dioxide to be taken in. Since less water is lost more water would be left in the ground. In addition to that the added plant growth whether as the result of more leaves per plant or more plants would further improve water retention as a result of less evaporation from the ground through less exposure of the ground to sunlight.

          • Robert: Again, thank you for your reply. However, I don’t disagree with anything you have written, especially:

            “They do not have to open as much nor to open longer for additional carbon dioxide to be taken in. Since less water is lost more water would be left in the ground.”

            However, you fail to acknowledge that warmth caused by more CO2 (if any) will also cause more water stress by increasing transpiration and evaporation. Which effect is more important? We don’t know.

            If you look at the OBSERVATIONS in Figure 1, you’ll see the first data set shows far more browning than greening in the Western US and Argentina, and the third shows the same for Australia. Few or no stars showing statistical significance.

            http://www.creaf.uab.es/Global-Ecology/Pdfs_UEG/2016_Zhu_et%20al_Nat%20Climate%20Change_2016.pdf

        • http://archive.news.iupui.edu/releases/2016/02/drylands-global-greening.shtml

          “The researchers examined the sensitivity of soil water change to varying levels of carbon dioxide, finding a significant positive change in soil water along the carbon dioxide enrichment gradient.

          “The stability of the rate of change justifies using higher carbon dioxide enrichment levels to interpret soil water responses to currently observed carbon dioxide enrichment,” Wang said.

          The analysis also showed that elevated carbon dioxide significantly enhanced soil water levels in drylands more so than it did in non-drylands, with soil water content increasing by 9 percent in non-drylands compared to 17 percent in drylands, Wang said. Determining the mechanisms of stronger soil water responses in drylands will require further investigation.”

          This is further supported by GRACE data showing higher water retention over land than hydrological models calculate.
          https://wattsupwiththat.com/2018/01/26/what-to-believe-models-or-grace-data/

          Evaporation happens more readily over water than land, so we’ll see a net transfer from oceans to land. Less demand from plants means more water available for other plants. Many plants also supply more carbon to soil and symbiotic bacteria and fungi which make nitrogen and phosphorus bio available as CO2 increase, this further increases the ability of soil to retain water. This creates a positive feedback cycle that will only accelerate as CO2 rises.

          The notion that drought and water stress will increase due to climate change, quite frankly, is ridiculous.

          • Aaron: The article you cite is an analysis of the a total of 45 separate papers involving increased growth from CO2 supplementation. Since stomata need to be open less often with higher CO2, the plants use less water. However, the second effect of CO2 all of these researchers believe in is that CO2 will produce higher temperature. Higher temperature means more evaporation. In these CO2 supplementation experiments, one gets the undeniable benefit of CO2 fertilization without the increase evaporation from higher temperature.

            Heat causes drought even when rainfall remains the same!. See the widely used Palmer Drought Index.

            https://en.wikipedia.org/wiki/Palmer_drought_index

            Aaron wrote: “This is further supported by GRACE data showing higher water retention over land than hydrological models calculate.”

            https://wattsupwiththat.com/2018/01/26/what-to-believe-models-or-grace-data/

            This is false. The article claims GRACE disagrees in both directions with models of water storage on land.

            The effect of climate change on the hydrologic cycle is complex, but models predict dying over land. In the real world, there is less greening in arid areas (see above).

          • More vegetation should be expected to increase water loss through transpiration. But this study found that the increase in transpiration due to “greening” has been closely balanced by the decrease in transpiration due to higher CO2 levels.

            https://www.nature.com/articles/s41467-017-00114-5

            An article about it summarized it:

            “Land plants are absorbing 17% more carbon dioxide from the atmosphere now than 30 years ago… [yet] the vegetation is hardly using any extra water to do it, suggesting that global change is causing the world’s plants to grow in a more water-efficient way.”

            Ref: https://wattsupwiththat.com/2017/07/30/rising-carbon-dioxide-is-making-the-worlds-plants-more-water-wise/

  43. I’d like to add this data to the evidence here:
    https://www.agprofessional.com/article/comparison-world-corn-yields

    and focusing on Argentina (as an analog for the USA and Canada)
    http://www.city-data.com/forum/attachments/weather/83943d1314056047-does-usa-have-most-climate-zones-mapaclimatico.gif

    I suspect that when rainfall, soil quality, and techniques are accounted for, that yields will continue to rise disproportionately to the USA is most countries and their climate zones.

  44. The IPCC has to predict food production will decline because if they say it won’t they eliminate a major calamity they claim is the result of warming. Starvation and loss of life from it. Of course, the idea that food production in 2080 would be less because of 2 C warming is absurd in so many ways as to defy intelligence. We have tripled output of food in the world in the last 60 years and we are on track to triple it again. By the time 2080 comes around we will have such an abundance of food that even if Global Warming somehow impacted our productivity it would make no difference. Also, as the author above points out their predictions are based on stupidity of farmers that is ridiculous. Higher temperatures will increase growing seasons and some places may have multiple growing seasons. Some foods may change locations but this is obvious. In total there will be more arable land and more water too. Higher temperatures mean more evaporation and more rain. Even they predict that.

    If they didn’t say that people will starve but that productivity will be enhanced then they would find the scare tactics they use become laughed at. This is why they NEVER talk about the benefits of global warming. If anybody thinks there is any benefit at all they know many people will shrug their shoulders. To keep the money flowing they need to have only negatives. No positives.

    So, they talk about how storms will increase when in fact the reduction in polar/equator temperature difference will lessen the energy available to storms. This is the most common sense result that is obvious but they ignore the common sense reasoning and tell us their models project higher storms. We haven’t seen it and won’t. They only look at reasons to become alarmed and discount any reason that might be positive.

    They don’t mention studies that show 23 times fewer people die from all causes for a N degree rise in temperature than from an N degree drop. The result is probably millions of lives saved from pneumonia, heart disease, lung diseases and other. They never mention this instead talking about some insect causing this or that death toll. They probably haven’t heard the news that we just created a much more effective vaccine. Oh well another global warming killer mitigated!!!

    Also, 20 companies are now started in 2 years to produce nuclear fusion reactors commercially. Many people say that by 2030 we will have commercially feasible fusion reactors. Crisis cancelled again.

  45. There’s something major that’s being missed here, and that’s the effect of science and breeding on crop yields. Companies have been concentrating on specific hybrids for specific climates since the 1940’s. If you take a typical hybrid or variety from 15 years ago, and compare it to a hybrid or variety that’s “current” you are going to see most of your yield difference. You would then need to tease THAT out of the CO2 data. Good luck with that.

Comments are closed.