Plant physiology will be major contributor to future river flooding

From The NSF

By hoarding water underground, vegetation will help saturate soil, boosting rain runoff

plants_flooding_f

Plant physiology will be as significant as climate change in future river flooding.

October 22, 2019

The next time a river overflows its banks, don’t just blame the rain clouds. Earth system scientists from the University of California, Irvine have identified another culprit: leafy plants.

In a study published in Nature Climate Change, the researchers describe the emerging role of interrelationships of organisms and their environment in understanding flooding. Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.

“Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere,” said study co-author Mike Pritchard of UCI. “Add this up over billions of leaves in very sunlit, leafy places, especially the tropics, and it means there is a bunch more soil moisture stored up underground, so much so that climate models predict rainfall events will saturate the ground and more rain will run into rivers.”

Pritchard said this so-called forest effect dominates atmospheric responses to CO2 on most land masses up to 30 degrees north and south of the equator, which is where most people live. And he noted that this plant-based phenomenon could have a large influence on flooding in the Mississippi River basin.

“I was really interested in the Mississippi because it’s in our own national backyard,” Pritchard said. “It’s a big, complex basin fed by multiple sources.”

He said the twin effects of plant physiology in the U.S. Southeast and precipitation anomalies caused by atmospheric warming farther north in the Mississippi basin “are conspiring to juice up the future flood statistics in equal proportion.”

The research is funded by NSF’s Division of Atmospheric and Geospace Sciences.

HT/Daniel L

Advertisements

86 thoughts on “Plant physiology will be major contributor to future river flooding

  1. The historical record is that when an area is deforested, floods and soil erosion become a big problem. link Greater vegetation, caused by more CO2, should decrease flooding.

    The other thing that occurs to me is that saturated soil causes plants to drown. Is that actually happening? I haven’t heard that.

    • Honestly, if a region is deforested it creates faster run-off creating flooding, and now if it’s too green it’ll create faster run-off creating flooding?!?! Funny, is this modelling supported by an actual eco-system example like, say, for instance, the AMAZON??

      • They say “Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere,”
        This is true. Water efficiency, a terrible thing I guess. Yet there are more plants to absorb water. Trees are larger and need more water. Root systems are stronger and hold the soil and nutrients better.

        BTW, run off in poorly grown areas is much heavier.

        • It sure happens in deserts – that’s the greening of the earth. Does it really work that way in the Mississippi watershed? Do authors have any data?

          This should result in less water vapor in the air. Do authors have any data?

          How does the soil moisture get in the soil? Do authors have any data?

          • Let’s see now, as New Orleans is itself just shy of 30 degrees north latitude, the Mississippi river basins is entirely outside of the dreaded 30 degree semi-tropical threatened planetary band. Whew, close call, but no cigar for any of the central continental United States to suffer this soggy bottom mechanism.

    • Beat me to it, commieBob.
      All my life I’ve been told that urbanization and loss of vegetation increases flooding.

      Now we are expected to believe the reverse. But, hey-ho, that’s global warming for you.

    • They premise of the article is flawed because of at least one major unstated assumption by the author(s):
      That all else will remain equal while plants use less water under conditions of ever increasing CO2.

      This is of course an unwarranted assumption, and almost certainly not the case.
      CO2 concentration increasing causes plants to grow fast, by a lot.
      Faster growth means larger and more heavily foliated plants and trees.
      In fact the changes which will occur are sure to be numerous and complex, and the feedbacks large.
      The entire premise seems to be very poorly conceived and thought out, and the conclusion follows the typical alarmist narrative: Anything that changes due to more CO2 in the air is bad, disastrous even.
      Not even given a mention are the numerous positives that might result from plants requiring less moisture to thrive, although the idea raised does point to one more possible benefit: Enhanced groundwater recharge rates.

      I see no evidence that the author(s) have any particular knowledge of or insight into hydrology or botany.
      The entire thing is chock full of densely overlapping grammatical and scientific mistakes.
      A middle schooler might get points deducted from an assay for this sentence, for example:
      “Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere…”

      Leak less underground soil moisture?
      Is this as opposed to leaking less above-ground soil moisture?

      And leaking water through their pores? Is this a reference to the basic process known, even to grade school kids, as “transpiration”? I think it must be.
      Also familiar to anyone who has even elementary school knowledge of plant physiology is that plant have structures called stomata, not “pores”!

      And what is up with this reference to a “carbon-rich atmosphere”?
      For one thing, regardless of the fact that calling CO2 “carbon” is now a widespread misnomer, it is still wrong, and an utterly unscientific usage to call it that.
      Additionally by well recognized historical standards, even the current 400+ ppm of CO2 can only be seen as highly depleted in CO2.

      And this single sentence is largely representative of the entire essay in regard to being poorly written to the point of being factually wrong, as well as appearing to have been produced by someone who is barely scientifically literate.

      Let’s look at this paragraph:
      “In a study published in Nature Climate Change, the researchers describe the emerging role of interrelationships of organisms and their environment in understanding flooding. Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.”

      The interrelationships between organisms and the environment is not an “emerging role”. These relationships may in fact be changing, but that is besides the point: What is being described is an emerging UNDERSTANDING, by the authors apparently, if no one else. Although it certainly seem to be an emerging misunderstanding. I suppose misunderstanding is one type of understanding.
      This mistakes and BS in this one paragraph could be the subject of an essay.
      CO2 is asserted to be in a state of overabundance, with no evidence or reason given to believe such is the case. Only by understanding that this idea is a central tenet of the global warming alarmism religious dogma can this assertion be accounted for.
      The term “pores” is used in place of stomata, as previously noted. Simply stated, the word pores is not interchangeable with stomata. Stomata are a type of pore, yes. But pore just meanings a small opening.
      Plants have other types of pores.
      And the pore is just part of the stoma, and does not exist the stoma is closed. IOW, the pore is the aperture itself, which is regulated by several complex and in some cases poorly understood processes involving pairs of cells called guard cells.
      Simply said, calling stomata “pores” bespeaks ignorance. Even in casual conversation, scientists (or farmers for that matter) talking about plant physiology do not typically call stomata “pores”. In a scientific essay, it sounds idiotic.
      The lack of proper language is hardly limited to a single or even a few words and phrases.
      It is replete throughout the essay.
      Some might say that referring to stomata as pores is not actually incorrect, since a pore is a generally term for any opening in a surface, and stomata are an example of one such type of opening.
      But in this same paragraph they refer to water being released by leaves as “evaporation”.
      For one thing, water vapor is what is released, and the process itself is never called evaporation. It has a separate name: Transpiration.
      Transpiration as a process is distinct from evaporation.
      The water vapor which transpires from stomata does have to evaporate of course. It evaporates into air spaces within the plant from mesophyll cell walls.
      The entire process involves water being drawn up through the plant. If vapor was simply evaporating, there would be no capillary action drawing new water into the roots and up through the xylem cells to the leaves.
      Water passing into the air happens by any of several processes, examples being sublimation, evaporation, and transpiration. They are purposely defined as distinct processes. It is flat out incorrect to refer to water transpired by leaves as evaporation.
      There is a separate process by which plants exude water, rather than vapor, and this process is called guttation.

      This is a paper on the topic of plant physiology that is published in the pages of the National Science Foundation.
      I for one am embarrassed for them.

      • Great idea Luke!

        Imagine the progress that could me made with just a fraction of over $2bn wasted on this sort of rubbish every year. The threat to life from cancer is orders of magnitude greater than the threat to life of a slightly warming world.

    • A couple of blunders in this analysis:

      1) Green plants evapo-transpire water, absorbing moisture from soils and transferring it to the atmosphere through leaves based upon factors like available soil moisture, relatively humidity, windspeeds, and direct sunlight exposure … thus plants dry out soils, and do NOT make soils hold more water.

      2) Green plants also physically retard surface runoff rates, just due to the much higher “friction” of flow over that of bare soils or rocks. The “time of concentration” is the measure of the land surface’s tendency to speed or retard surface runoff flow rates, and directly controls peak runoff rates from a given watershed. The shorter the Tc (from a lightly vegetated surface) the faster the runoff collects leading to a higher peak runoff rate from the watershed. Likewise, the longer the Tc the lower the peak runoff rate from a given watershed.

      Vegetation cover thus not only dries out soils but greatly slows the surface and near surface transport of rainfall runoff into streams and rivers. The “time of concentration” is what greatly affects the peak runoff rates that can lead to flooding.

      Engineers take this into account in calculating watershed flood analyses. I’m a degreed and licensed civil engineer. This is what we do.

      This paper is yet another example of a little knowledge – but nowhere near enough – is just enough to be dangerous.

      A greening world is a world much less subject to dangerous flooding, especially flash flooding. That is why the steep terrain of desert areas as in the American southwest experience far more drastic flash floods than do the heavily vegetated lands of the eastern half of America.

      • That is why the steep terrain of desert areas as in the American southwest experience far more drastic flash floods than do the heavily vegetated lands of the eastern half of America.

        True, and a leaf canopy will also break up/slow down raindrops falling at speed so that the impact on soil (covered or not) is greatly lessened.

  2. Right, time to stop using anything which produces co2, all humans, all plants must go! 😐 When will this bulls#hit stop? The constant lies upon lies are past boring.

  3. They totally ignore the fact that there are and will be more plants, bigger plants , more and bigger leafs !
    The global plant water consumption should go up .
    Did someone study actual, in the field, water consumption in CO2 richer and warmer atmosphere ?

    • Exactly. For most locations, for at least some part of the year, water is limiting. More soil water will generally equal more leaf area, which should offset some portion of the increased water due to increased evapotranspiration. Evidence from experiments in temperate forests where vegetation is removed (fire or clearcutting) shows the watering up effect is transient. The quick regrowth of shrubs, herbaceous cover, and eventually trees can bring streamflow back to baseline within 5 years, rarely past 10.

      An example of experimental quantification of stream flow response to vegetation removal:
      https://cfc.cfans.umn.edu/sites/cfc.cfans.umn.edu/files/Stednick_1996_JHydro.pdf

      A review paper in temperate conifer dominated headwaters.
      https://www.sierraforestlegacy.org/Resources/Conservation/FireForestEcology/FireScienceResearch/FuelsManagement/FM-Nitschke05.pdf

    • That’s my take on it too… they isolate a mechanism that could increase runoff from related offsetting mechanisms that would reduce runoff.
      Whatever you may think about climate scientists, when it comes to feedbacks they’re really quite a positive lot.

    • If the water in incorporated into plant tissues, then how does it contribute to soil moisture? This make no sense.

    • You can bet that no one actually went outside or even into a lab to produce this steaming heap.
      More science by thought experiment and assertion, with the only important thing, that which ensures publication, is that it is bad news and it is caused by CO2.

  4. At last they have found a downside to increased global greening! That must rate alongside eliminating the Medieval warm period as a propaganda target.

    • They haven’t found anything. They are simply creating a new falsehood based upon shoddy thinking.

      • Exactly.
        And shoddy writing, using language that would get a sixth grader scolded and a grade of D or worse.

  5. Oh, good grief! Does this grant-seeking desk jockey realize that water on the surface slowly, slowly, slowly sinks into the dirt and trickles DOWN into the water table over a period of time????? Or does it occur to him EVER that there are such things as catch basins — which WE have around here — which can be set aside to hold excess rainwater from big and small waterways and allow the soil to absorb it and let it sink into the SUBSURFACE water table?

    When I see a local river flooding, one that is a major contributor to the Mississippi when it hooks up with the other rivers to the south, which then hook up with one river that empties into the Mississippi River, I also try to find out if Lake Michi Gamu is WAY high and flooding areas near its shores, and guess what?!?!? That is frequently exactly what happens! Holy cow!!

    Mother Nature knows a lot more about her business than the desk jockeys and their computers. Computers only provide information that was added to their memory banks.

  6. Ok, 30 degrees north or south. Mississippi River Basin? Let me check my map. Don’t think much of that basin will be affected, if an actual effect exists. Seems squishy to me.

    • New Orleans is at 29.9511° N. Latitude, so basically non of the Mississippi falls into the
      30° N & S latitude area cited in this paper.

  7. climate models“. Will the garbage coming out of climate models never end? Increased vegetation reduces floods, because it slows down the flow of water.
    https://whyfiles.org/107flood/3.html
    http://www.greening.in/2013/05/how-trees-help-in-preventing-floods.html?m=1
    https://isha.sadhguru.org/rally-for-rivers/how-trees-reduce-flood-droughts/
    even The Conversation is inclined to agree:
    https://theconversation.com/can-we-really-prevent-floods-by-planting-more-trees-52160

  8. “Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.”

    Doesn’t this imply that there will be Less atmospheric water vapour to form clouds?
    If so, won’t that reduce rainfall?

  9. Global warming induces :
    – more drougths : bad !
    – a more green planet : good ! (Ouch, this is very BAD for our “all is bad from GW religion”)
    We positively have to find something negative with this greening …
    – let’s observe (from some new fake ad hoc model) that this greening induces more floods : bingo !

    Our religion is again consistent with our observations.

    The Ministery of The Climate Clowns Truth.

  10. “Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.”

    Thus the “positive feedback” due to more WV evaporated from vegetation which has grown more thanks to more CO2 is a pure bullshit.

    The climate clown show never ends !

  11. I’m starting to realize that articles like this aren’t produced for science, they are written just to get the phrases ‘overabundance of CO2’, ‘carbon-rich atmosphere’, and ‘atmospheric warming’ into literature so that they add to the statistics of future digital searches for those catch-phrases.

    The Mississippi floods because it rains, no other reason. Man has confined it to one channel and not dredged it; leaf the carbon rocket science out of it. The river bottom between levies being higher than the surrounding land is the root of the problem. (I had tree points, but forgot the last one.)

    • Just read the abstract and supplemental information. It appears to be 100% model output mislabeled as data.

      • Unfortunately, my institution gets this journal with a 1 year embargo, so I will never read this article. The abstract and supplemental data indicates this is an exercise in study for the video game version of Earth and not the actual planet. If the assumptions that went into the model were real, it might be somewhat similar to real earth, but since it starts with the absurd assumption that plants which evolved under a higher CO2 concentration than we are likely to naturally encounter again somehow don’t know how to handle CO2 levels just above plant starvation levels, it is unlikely to be even close.

    • OweninGA,

      Model porn. Author’s info:

      Michael Pritchard
      Assistant Professor
      University of California, Irvine, Department of Earth System Science

      Expertise in next generation climate simulation.

      Focuses on the physics of cloud-related processes in the virtual atmosphere.

      Applies a range of traditional and experimental new approaches to study the global atmosphere in a virtual laboratory, including conventional global climate models and experimental approaches such as “superparameterized” prototype global models.

      Expert in next-generation climate simulation, global models and the physics of cloud-related processes in the virtual atmosphere.

      Research Areas:
      Physical Climate

      Research Labs:
      Pritchard Lab

      • I figured. Models have their place, but they aren’t the end-all be-all. If the physics in the model is real enough, the output from the model is great for telling you what to go spend money on measuring in the real world. The problem in the modeling community is they mistake their output for data. Only things measured in the real world can ever be called “data”, everything else is called “theory” or “fantasy”.

  12. Another example of the anti-life nature of “climate science” in todays anti-universities.

    Healthy plants in a healthy soil improve soil structure, so that it holds both moisture and air. For a better understanding of the real dynamics of plants and floods, read Judith Schwartz’s book “Water in Plain Sight.”

    Bare-soil farming reduces topsoil, destroys soil aggregates (lumps) leading to high runoff = floods, and this is followed by droughts, exactly as happened to the American Midwest this year.

  13. Not enough variables in the suggested land absorption model and it does not start to correlate with the real world
    I live in a smallish village in an area with many small well defined aquifiers with a high percentage of houses fed from them and where it rains, and do gardening so I know a thing or two about it

    well, that ,
    and , and the fact I have a good sized subteranean lab within in the Vadose layer , with earth walls and earth roof (and the occasional rockfall) with temp and humidity dataloggers running occasionally (as recommended by the WUWT website)
    18 inches of topsoil grading down to regular clay with iron and quarts inclusions, a 10 deg inclined strata and with 100 % bush cover above, it never ceases to amaze me when I`m down there just how detached, and variable, the water penetration is, in terms of real free flowing water and strata moisture content, relative to the actual rainfall above, even the very fine ends of the roots that slowly creep along the surface looking for a home occasionally leak water/sap.
    A simple process diagram with peak and mean flow rates, with limits will show everything you need to know.

    • “…it does not start to correlate with the real world.” These “studies” never, never, ever relate to the real world.

      I thought research meant going outdoors, taking samples, doing in locus observations. Obviously, things have changed and models reflect what the modeler wants, NOT the real world.

  14. “Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume.”
    Yes. This is why in greenhouses they raise CO2 levels to 1,000 ppm. It’s to torture the plants. The poor dears are literally drowning in CO2. This cruelty is an abomination, and must be stopped.

  15. “Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere,” said study co-author Mike Pritchard of UCI. “Add this up over billions of leaves in very sunlit, leafy places, especially the tropics, and it means there is a bunch more soil moisture stored up underground, so much so that climate models predict rainfall events will saturate the ground and more rain will run into rivers.”

    Bullshit!

  16. Exactly 100% wrong. Higher density ground vegetation slows runoff (and erosion).

    And the vegetation density is increasing from CO2 fertilization.

    The bigger problem of drought recedes with the increase in plant respiration efficiency.

    Total bullcrap study.

    AND the dumb ass Republicans just heloed to reauthorized Climate Research funding. Brings a few $100,000 to their districts AS IT TRIES TO DESTROY THE COUNTRY !

  17. Any effect caused by increased CO2 (the anthro type, you can see the difference) is by definition, a Bad Thing. The earth has been greening as more leafy plant growth has more nutrition, a slow motion feeding frenzy. If we think hard enough, we should be able to figure out a Bad Thing in there somewhere.

  18. Higher CO2 levels: increase crop yields, increases biomass to better feed all life on earth, increases all plants’ root network which DECREASES soil erosion, and increases plants’ drought resistance….

    “Scientists” who say higher CO2 levels will increase river flooding are either blithering idiots or are immoral and unethical grant-grubbing charlatans.

    • We had an eight inch rainfall event between September 21st and October 16th 2019 in NW London, UK, including two 2 inch+ events in 12hrs.

      I had a variety of leafy plants in my garden and they utilised this rain to grow extremely rapidly over a three week period.

      My soil happens to have been well looked after the past five years and there was no run off, no standing water, nothing but effective absorption and drainage through pores developed by worms. The soil was bone dry at the start of the event after six weeks of drought (the second long dry period of summer 2019). At the end of it, it was recharged to depth.

      Run off leading to doenstream flooding is a function of various things, including but not limited to:

      1. % of rainfall not reaching the ground uninterrupted through adherence to plant structures off the ground.
      2. Absorption capacity of soil where rain is falling, linked to soil type, organic matter content of soil, structure of soil (notably worm passages etc), gradient of land etc.
      3. % of any run off delayed from reaching lower river courses by leaky or non-leaky dams, % overspill into flatter terrain capable of absorbing excess water over time, prevalence of ditches capable of storing surface water.
      4. Rate of absorption of rainfall by vegetation, linked to rates of photosynthesis, respiration and transpiration (anyone else noticed that tomatoes increase their rate of water absorption from 16C up to 32C?)
      5. % saturation of soil prior to current rainfall event.

      My observation is that soil condition is a far greater factor in inability to drain heavy rainfall that what particular plants happen to be growing. Or what temperature it happens to be.

    • Samurai,
      I see zero evidence that whoever wrote this has even high school level knowledge of botany, let alone hydrology.
      There is a demonstrable ignorance of edaphology.
      IOW…no evidence any scientist was involved.

  19. A perfect example of picking a few known facts, ignoring others and completely disregarding unknowns.
    The end result is that a completely wrong conclusion is drawn, either on purpose for political reasons or simply though stupidity. Let’s hear your vote. Mine is for stupidity.

  20. “In a study published in Nature Climate Change, the researchers describe the emerging role of interrelationships of organisms and their environment in understanding flooding. Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.

    Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere,” said study co-author Mike Pritchard of UCI. “Add this up over billions of leaves in very sunlit, leafy places, especially the tropics, and it means there is a bunch more soil moisture stored up underground, so much so that climate models predict rainfall events will saturate the ground and more rain will run into rivers.

    N.B.; the trail where the authors leap to stupendous results, without verification, certification or observation.

    N.B.; where plants originally leaked excess water and now ‘retain water”?
    Presumably, plants replaced their leaked water with more water intake; otherwise the plants suffer for lack of water.
    Yet, somehow, the authors conclude that plants that did not “leak” result in more water in the soils?

    A comparison would be that sinks/tubs leaking water in a bathroom result in less water on the floor versus sinks/tubs that do not leak result in more water on the floor?

  21. Reductio ad absurdum: If there’s a plant, reduced evapotranspiration; No plant, no evapotranspiration, all water runs off. Now which is the most favourable outcome, I wonder?

  22. ““Adapting to an overabundance of carbon dioxide in the atmosphere, trees, plants and grasses constrict their pores to regulate the amount of CO2 they consume, a mechanism that limits the release of water from leaves through evaporation.”

    No, plants do NOT “consctrict their pores to regulate the amount of CO2 they consume”… and it is NOT “adapting to an overabundance of carbon dioxide in the atmosphere”…

    Plants open their pores to obtain CO2 from the air. They get water from the ground. Opening the pores to obtain CO2 from the air causes the simultaneous loss of water vapor OUT of the pores. Higher atmospheric CO2 levels means they obtain the CO2 in less time and close their pores sooner. This is NOT an “adaptation” to CO2 “overabundance”, as it works the same way in any Greenhouse with artificially elevated CO2. It is a win-win situation for plant life, as they lose less water in the transaction and become more water efficient, leading to healthier plants, and biota in general.

    This study has it all backward, trying desperately to make a good thing into a bad one with purposely negative terminology (“overabundance of CO2”, “constrict their pores”, “regulate the CO2 they consume”). Standard climate “science”, unfortunately.

  23. I can only imagine the horror when Fowler, Kooperman, Randerson & Pritchard discover that fully 70% of the surface area of the entire planet is wide open to evaporation of water into the atmosphere… all that leaky water vapor emanating from vast pools of naked surface waters!

  24. So the plants are countering the water-table declines caused by groundwater pumping, thus reducing subsidence-related flooding?

  25. The only palpable sign of climate change IS the Great Greening and its other manifestation – burgeoning harvests. This greening and plentitude is untold $ trillions for the benefit side of CO2.

    The central planners have been worrying about this apparently unexpected bounty since it was reported by NASA about 6 yrs ago. Except for some desperate, lame and laughable attempts at painting a dire picture of this exciting phenomenon shortly after the NASA report, there has been essentially a pregnant silence on the subject. Even sceptics somehow have largely kept their heads down for some reason.

    I have been promoting a quantification of this for several years, seeing it to be a sledgehammer argument against alarmist nonsense. Grossly, I learned a number of years ago the world’s trees had been counted – 3 trillion of them. I learned that in 35 yrs forests expanded 14% (up to 2013), so let’s conservatively say 16% to today – so we’ve added 480billion trees to the planet, not to mention shrubs, grasses, fattening of existing plants etc., plus oceans of new pelagic relatives. Any foresters or arborists out there to analyze all there?

    Since the nature of fringing growth into arid regions (the main noticeable greening places) is an exponential process, logically the CO2 growth rate in the atmosphere will attenuate to a plateau, even doing nothing deliberate to abate it. CO2 is simply overwhelmingly beneficial.6

  26. Two very different issues being confounded here. First, the extra water efficiency of plants in higher CO2 translates to faster growth in areas which are limited by water. Where there is already adequate water, such as tropical forests, it has little or no effect as however much CO2 is in the air, it gets sucked up pretty fast.
    Once again, where there is no water stress, the impact on soil moisture is also negligible as the very definition of water stress is inadequate soil moisture, leading to reduced leaf turgor and closing of leaf stmata (pores) to conserve water.

    It is drawing a very long bow from higher CO2, through less water stress, to increased soil saturation and then on to more flooding with a series of rather tenuous links which will probably only apply in a very small number of environments. I am sure the authors have some experimental data to back this up, but as a general mechanism to point to higher flooding, this is just extrapolation of the highest order.

  27. Every time I see a “study” like this I can’t help but wonder about how seemingly little knowledge the authors must have about this planet’s climate history in regards to life on earth. Based on models like this, one must wonder how the dinosaurs (and the mammals that came after their extinction event) could possibly have survived, let alone thrived, in such a cataclysmic world. Except for the fossil records show that life flourished during earth’s warmer periods. And as for past mass extinctions, most (as far as anyone can determine) have been caused by excessive vulcanism, freezing temperatures and asteroid impacts. None of the warm periods have been catastrophic (and indeed some were much warmer than today; how did plants back then ever cope?) to animals and even to humans in recent history. Seems that so many climate “scientists” are quite deficient when it comes to geological history…..

  28. The worst thing that happened to the Miss. River was *levees*! Simply physics – Building/raising levees raises the riverbed which, in turn, raises the water level.
    Think about that whenever cities along the Big Muddy.

  29. Elevated CO2 has increased root growth to an even greater percent than leaves. The cited report should have taken that into it’s modeling, if has not done so.

    Am multitasking so will post this & follow with an old example for orientation soon.

    • For example: Going from 350 ppm CO2 to 700 ppm CO2 in soybeans results in a 110% increase in root length. Their root diameter increases 27%, their cortex diameter increases 23% & their stele diameter increases by 28%.

      In context of root fluid content that increases by 80%, as measured in ml. As per 1992 “Response of plant roots to elevated atmospheric carbon dioxide”; free full text available on-line has more data in Table 1.

      In soybeans elevated CO2 does not however increase the number of lateral roots. This is a feature of how plant hormones differentially respond to CO2 levels – which is why I’ve previously said elevated CO2 can be considered a stressor to current plants.

  30. I admit I’ve only skimmed previous posts, but a point raised by Gregory Wrighthouse, in an interview plugging his book Inconvenient Facts, was that increased soil moisture is contributing to a reduction in forest fires.

  31. I’m no botanist and even I can recognize this is complete nonsense, and as such the BBC and Dungaria will be all over it. If they aren’t already.

  32. Wow! This must be one of the dumbest papers ever published. I can’t wait for this superstition to be placed alongside Bigfoot, where it belongs.

  33. Umm virtually all of the Mississippi basin is higher than latitude 30 N. The St. Louis area pictured is about 38 Latitude North. Baton Rouge is about 30 N. So once again, more easily identified climate baloney..

  34. They say “Plants get more water-efficient and leak less underground soil moisture through their pores in a carbon-rich atmosphere,”
    This is true. Water efficiency, a terrible thing I guess. Yet there are more plants to absorb water. Trees are larger and need more water. Root systems are stronger and hold the soil and nutrients better.

    BTW, run off in poorly grown areas is much heavier.

  35. I’ve never read such a bunch of crap. ”Science” these days seems to be as much about speculating on someone’s dreams as it is about observation and experiment.

  36. The thing that I hate more than the fact that global warming causes droughtflood summers is that it causes warmcold winters. Even worse is all the raindroughtsnow.

  37. Surely this is a good thing? Isn’t more moisture left in the ground better and likely to make droughts less likely? Some people just don’t like to consider there may be an upside to more CO2 I guess. I wish people would call it that BTW- not ‘carbon’, but I also wish I had a Ferrari- I suppose I just want too much…..

Comments are closed.