High CO2 levels cause plants to thicken their leaves, could worsen climate change effects
Plant scientists have observed that when levels of carbon dioxide in the atmosphere rise, most plants do something unusual: They thicken their leaves.
And since human activity is raising atmospheric carbon dioxide levels, thick-leafed plants appear to be in our future.
But the consequences of this physiological response go far beyond heftier leaves on many plants. Two University of Washington scientists have discovered that plants with thicker leaves may exacerbate the effects of climate change because they would be less efficient in sequestering atmospheric carbon, a fact that climate change models to date have not taken into account.
In a paper published Oct. 1 in the journal Global Biogeochemical Cycles, the researchers report that, when they incorporated this information into global climate models under the high atmospheric carbon dioxide levels expected later this century, the global “carbon sink” contributed by plants was less productive — leaving about 5.8 extra petagrams, or 6.39 million tons, of carbon in the atmosphere per year. Those levels are similar to the amount of carbon released into the atmosphere each year due to human-generated fossil fuel emissions — 8 petagrams, or 8.8 million tons.
“Plants are flexible and respond to different environmental conditions,” said senior author Abigail Swann, a UW assistant professor of atmospheric sciences and biology. “But until now, no one had tried to quantify how this type of response to climate change will alter the impact that plants have on our planet.”
In addition to a weakening plant carbon sink, the simulations run by Swann and Marlies Kovenock, a UW doctoral student in biology, indicated that global temperatures could rise an extra 0.3 to 1.4 degrees Celsius beyond what has already been projected to occur by scientists studying climate change.
“If this single trait — leaf thickness — in high carbon dioxide levels has such a significant impact on the course of future climate change, we believe that global climate models should take other aspects of plant physiology and plant behavior into account when trying to forecast what the climate will look like later this century,” said Kovenock, who is lead author on the paper.
Scientists don’t know why plants thicken their leaves when carbon dioxide levels rise in the atmosphere. But the response has been documented across many different types of plant species, such as woody trees; staple crops like wheat, rice and potatoes; and other plants that undergo C3 carbon fixation, the form of photosynthesis that accounts for about 95 percent of photosynthetic activity on Earth.
Leaves can thicken by as much as a third, which changes the ratio of surface area to mass in the leaf and alters plant activities like photosynthesis, gas exchange, evaporative cooling and sugar storage. Plants are crucial modulators of their environment — without them, Earth’s atmosphere wouldn’t contain the oxygen that we breathe — and Kovenock and Swann believed that this critical and predictable leaf-thickening response was an ideal starting point to try to understand how widespread changes to plant physiology will affect Earth’s climate.
“Plant biologists have gathered large amounts of data about the leaf-thickening response to high carbon dioxide levels, including atmospheric carbon dioxide levels that we will see later this century,” said Kovenock. “We decided to incorporate the known physiological effects of leaf thickening into climate models to find out what effect, if any, this would have on a global scale.”
A 2009 paper by researchers in Europe and Australia collected and catalogued data from years of experiments on how plant leaves change in response to different environmental conditions. Kovenock and Swann incorporated the collated data on carbon dioxide responses into Earth-system models that are widely used in modeling the effect of diverse factors on global climate patterns.
The concentration of carbon dioxide in the atmosphere today hovers around 410 parts per million. Within a century, it may rise as high as 900 ppm. The carbon dioxide level that Kovenock and Swann simulated with thickened leaves was just 710 ppm. They also discovered the effects were worse in specific global regions. Parts of Eurasia and the Amazon basin, for example, showed a higher minimum increase in temperature. In these regions, thicker leaves may hamper evaporative cooling by plants or cloud formation, said Kovenock.
Swann and Kovenock hope that this study shows that it is necessary to consider plant responses to climate change in projections of future climate. There are many other changes in plant physiology and behavior under climate change that researchers could model next.
“We now know that even seemingly small alterations in plants such as this can have a global impact on climate, but we need more data on plant responses to simulate how plants will change with high accuracy,” said Swann. “People are not the only organisms that can influence climate.”
###
From the UNIVERSITY OF WASHINGTON. The research was funded by the National Science Foundation and the UW.
Somehow, I just can’t let this disastrous news worry me, and did they consider that leaves that are 33% thicker store more carbon in the leaf?
So, this is something that “will” happen according their fairy tale carbonastrophic models. Riiiiiight. And we should believe them because…..
Branches will fall off trees because of the extra weight. If they fall on your head, they may damage your intellectual capacity. Unless you’re a climate scientist, of course.
Mower blades – must stock up on mower blades before the price goes through the roof.
More disaster!
I’m missing where any actual science was conducted here. Is this how elusive press releases need to be now in order to hide the BS?
Jeez, as if human obesity wasn’t the only problem, now we have to worry about plant obesity as well.
And in both cases it’s all our fault.
Elevated CO2 is a plant stressor (abiotic) that upregulates some gene transcription factors & down regulates others. For example: thick leaves have increased levels of the enzyme glutamate de-hydrogen-ase, which confers tolerance to water stress.
Growing leaves’ mesophyll cells divide faster than leaf outer (epidermal) cells. While thick
leaves’ mesophyll palisade cells grow more than mesophyll spongy cells. So elongation of
the palisade cells involves triggering specific
niche(s) of meri-stem cell(s) & thick leaves show certain up-regulated plant hormones.
While thicker leaves may mean CO2 has more
issues getting through the denser packaging of larger mesophyll cells (more distance to move) I think this over-simplifies
the circumstances. The greater palisade cells’
height (elongation) confers better light access & thus improved photosynthetic efficiency; while there is also proposed a better enzymatic activity of carbonic
anhydr-ase. But in low light eCO2 has been demonstrated to cause reduced mesophyll conductance of CO2.
{Am posting this in case lose wifi. To be cont}
Thicker leaf degree even among the same kind of plant can vary. In other words some genetic characteristics in any one plant will work out to more elongated mesophyll palisade.
In the plant strain with comparatively “longer”
palisades it will have relatively slower leaf initiation, vegetative growth & lower seed weights (also often lower number of seeds).
When comparing the same kind of plant to
another of it’s own kind in this context the strain that has higher (& wider) mesophyll palisade cells is that way because it’s chromosome set(s) divided more times (endo-ploidy) than the thinner leaf cell.
Plants can have more than 2 full sets of chromosonme in a nucleus; called poly-ploidy.
In terms of leaf thickness variation among the
same kind of plant strains the greater ploidy number then the greater leaf thickness possible. The leaf mesophyll cell in this comparison is a result of endo-poly-ploidy.
I mention this because many cite greenhouse
grown plants when discussing eCO2. A lot of
greenhouse plants are poly-ploidy, as are field
plants. So whenever making comparisons about aspects like leaves or eCO2 performance it really should take into account any ploidy number difference (ex: when researchers report varied response to eCO2 of the same kind of plant).
Just for orientation, here are a few examples
of how human’s selected for plant poly-ploidy.
Seedless grapes are tri (3)-ploid, while jumbo grapes are tetra(4)- ploid; other poly-ploid crops commercialized are strawberries, bananas, kiwi fruit & seedless watermelon to name only a few.
I’ll address the often commented fact that CO2 was higher in the past & plants thrived. In nature plants can also become poly-ploidy, so
the specific plant we may be discussing at any time can have aspects (like leaf thickness) we don’t think about. When I say eCO2 is a stressor I am considering the poly-ploidy evolution of many plants we grow has in some
aspects made some of a specific plant’s response to CO more intricate than it was long ago.
What should be understood about plant poly-ploidy is that just the fact a plant has gained any extra dual set of chromosomes the way that plays out in that plant may be quite different than any extra dual set of chromosomes in another plant. Sometimes the
change is worse for the plant – but this is not
to say eCO2 is undesirable, maybe more non-linear an actor than commonly described.
Oh noes ! More CO2 will cause alarmists to thicken their brains and further take leave of their senses
Shrinking glaciers I am good with that. Longer more productive growing season I am good with that. Rising oceans I live at 7500 feet I think I am good. However thick leaves has me a bit scared. I mean if plants put all there energy into leaves, instead of seeds we will starve.
Nah, we wouldn’t starve — with all the humans on Earth, there’s plenty of meat to go around — it’s just a matter of changing one’s tastes, ethics, and morals a bit. But, hey, cannibalism would be for a good cause — population reduction, etc.
Then the survivors could finally build their dream world ,with massive expanses of noisy, bird-killing windmills and bright, landscape-metallized solar panels.
Humans — the new white meat.
There were only 7 Democrats in Hinsdale county, and Alferd Packer ate 5 of them.
https://truewestmagazine.com/eating-his-weight-in-democrats/
when I read this article, my pet bull started to cry, he just can’t keep up to these “scientists”
Won’t all of the outgoing LWR already be absorbed before we even get to 900 pm?
“a fact that climate change models to date have not taken into account.”
Excuse #387 on why the models don’t work well.
Gee – I always observed that the leaves of plants where water is scarce are thicker because they survive better: eg the California deserts. Perhaps the U0f W researchers forgot to tell those plants that lack of water is OK but the forthcoming disaster in CO2 causes leaf thickening [I HATE it when my leaves get thick!]
Gee – I always observed that the leaves of plants where water is scarce are thicker because they survive better: eg the California deserts. Perhaps the Uof W researchers forgot to tell those plants that lack of water is OK but the forthcoming disaster in CO2 causes leaf thickening [I HATE it when my leaves get thick!]
My waist has been getting thick. Can I blame that on CO2?
As one of the letters says, “Go into a Greenhouse which has the higher levels of CO2 and observe. But no, thy much prefer to instead use “Models”and their PC’s, the modern Chrystal ball. And like the fortune tellers they can then make up the stories about anything.
And of course at the root is the usual indirect cry for yet more funds. We are so close to a major breakthrough, if only we had more research funds.
MJE
Makes sense to me. Current CO2 levels are still near starvation for plants. To get enough CO2 to grow, they need thin leaves so the scarce gas gets to the chloroplasts. Raise CO2 and leaves can be thicker and more efficient. This might be one reason plants need less water with more generous carbon dioxide.
Funny how these activists, I mean ‘scientists’, got off their duffs in order to find anything bad with the extra CO2 in the air that is fertilizing plants and causing the world to get greener.
So far, I’ve seen 3 different recent studies that said the extra CO2 is causing plants or trees the following maladies:
1) Food is less nutritious.
2) Wood in tress is a little weaker.
3) Leaves are thicker resulting in the tress being less efficient in taking in CO2.
Hmmm, I wonder what other bad things the extra CO2 is doing to plants and trees that these activists, I mean ‘scientists’, are going to ‘scientifically find” out? Anybody want to take any guesses at it?
I also predict ANY OTHER THINGS (if any come along, such as lower heating bills) that are bettered by extra CO2 in the air are going to eventually ‘found’ out to be worse than the benefit by ‘science’ studies.
Meanwhile, The Break Through Institute, a project of Rockefeller Philanthropy Advisors, Inc. (at least as of around 2013), thinks that we public simpletons and maggot scourges of the earth, follow the opinions and views of the elites:
“…years of research also suggest that public opinion follows elite opinion. The public is divided because elites are divided. A better future for people and the environment will require better elites.”
https://thebreakthrough.org/index.php/dialogue/ecomodernism-2018-achieving-disagreement
Maybe we ‘follow’ the opinions of the elites because the Rockefeller foundation has both spent a fair amount of money on how to sway public opinion and because they helped create the International Press Institute (around the end of WWII) and at which point, they had around 1,400 editors under it. They say it was created to spread democracy. Maybe. Or maybe it was created so that they could make the world a safer place for rich people…
Plant structures and chemical physiology have been evolving to changing climates and environments since the origin of life on Earth.
The Earth’s surface, oceans, etc. are part of that evolution, along with soils and microscopic life interacting and co-evolving with each other, resulting in an atmosphere that is entirely of biological origin (except Argon)
That’s why a Biologist understands how the Earth evolves compared to a physicist.
http://www.plantphysiol.org/content/125/3/1198
Your answer shows why you need a physicist and how biologist can fail so badly it hurts.
Perhaps type “source of all the elements on earth” into a search engine and come back and adjust your answer. Even wikipedia will give you the answer in a nice coloured table first one down is elements by source (https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements)
You would need to have a perverse definition of the word “origin”.
Obviously life on Earth now exists under an atmosphere that has physical properties. Solar energy is obviously abiotic. The point is the primacy of how global biogeochemical cycles have evolved biologically over geological time. Physical properties then respond to biological changes.
Life changes, physical properties respond to those changes.
The N2, O2, O3, H20 and CO2 in the atmosphere are not elements, they are molecules, and are considered abiotic in the most basic sense.
Atmospheric Argon gas is entirely of radioactive decay
http://www.accuracyingenesis.com/atmargon.html
Earth’s atmosphere has evolved over geological time due to biology. It’s called atmospheric evolution. Anyone can find an overwhelming amount of published science papers and reviews on the subject.
For example
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019231/
Or,from the point of view of the individual global biogeochemical cycles, N2, O2, CO2.
For example, the global biogeochemical nitrogen cycle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5412885/
Molecular oxygen and molecular carbon dioxide also have well established and quantitative global biogeochemical cycles that have evolved since life began.
Phosphorus and sulfur also have global biogeochemical cycles, but are not usually considered important atmospheric components, with some exceptions, such as volcanic and submarine sources.
Water has such a huge impact due to Earth being an ocean planet, but is usually not considered biological, even though it is the universal solvent of life.
So, my point remains, the amounts and balance of the various components of the Earth’s gas phase atmosphere are entirely caused by the living properties of the global biological ecosystem, and how that ecosystem evolves over long time scales.
You still miss the point that beside the hydrogen and helium, most of everything that is here comes from stars in space. All biology and geophysical process do is move the concentrations of elements around they can not change the percentages. All your cycles you think are so important rely on there being those elements here in the first place in an accessible form.
To that end if you type into a search engine “Origins of Earths Atmosphere” and “Origin of Eaths Water” you will also basically get the same answer. Initially molten Earth had no atmosphere and no water as it cooled volcanoes and gases spewed out from the solidifying rock as they were unable to be held in suspension anymore. So we get an atmosphere and a hydrosphere and no life involved in the process at all, not even relevant.
All life has ever been doing is polluting that pristine enviroment ever since as it replicates because that is what life does in exploiting an enviroment. So your life cycles may be all very interesting but please do not ever call them the origin of anything here on Earth.
Your “point” is rejected as irrelevant, and useless.
Quantum physics and cosmological big bangs are not essential to understanding life on Earth. I never said that primordial Earth had life, but it did include the ingrediants.
Your claim that molten Earth had no atmosphere or water is clearly false. There was a primordial atmosphere, and water in the gas phase was certainly a part of that. You don’t really have the first clue in that regard.
The origin of life on Earth is certainly a good time point to start examining the evolution of life on Earth. And that process of evolution did begin the inevitable transformation of the Earth’s ocean and atmosphere into what exists today. Directly causative.
Your claim that life is pollution would be a good bumper sticker for you.
I do find you amusing .. you reject it .. like your opinion matters.
Climate Science for Dummies in a Nutshell:
Lurking behind every negative feedback is an opposite and even-worse-than-we-thought positive feedback.
“ . . . cause plants to thicken their leaves . . .”
And plants
” . . . would be less efficient in sequestering atmospheric carbon”
We live in a fairly dry environment – ~9 inches of precip per year. Maybe I should read the entire thing, but fallen leaves get crunchy and broken into many tiny fragments. These do not sequester carbon for very long, It is mostly a short cycle. I fail to see the interest therein. Besides, thicker leaves would last longer.
However, small woody plants and trees do last quite awhile in a dry environment and the sequestering cycle is much longer. Black Cottonwood and Ponderosa Pine get quite large and have long lives. Would their volume (mass) decrease? Would their lives shorten?
Without knowing all the specifics of this report, I am left a bit confused.
Black cottonwood has a taller & a shorter variety. Ponderosa Pine has a more drought resistant & a lesser drought resistant variety.
I won’t try to describe anywhere along these
gradients, but their relative relationships show
up in researched samples not always exhibiting the same data.
What seems relevant is how the more drought tolerant Ponderosa Pine immediately uses a lot of water when available & most promptly
closes leaf stomata when water not there. Now
the original post’s idea is since thicker leaves
have crowded interior space less CO2 can be in
the space. Yet some researchers suggest elevated CO2 also instigates more aqua-porins
(passageway for water through a plant cell
membrane).
So, without parsing which type of tree & what
growth phase I am inclined to think elevated
CO2 itself is [not] going to shorten every tree’s lifespan. (There is an issue with elevated CO2
engendering growth using water whereby more surrounding trees in turn take water out
of play for neighboring trees.)
Edit: Not going to shorten …. lifespan: is what meant to write.
One thing for sure that it’s not going to do, and that’s make it warmer. As we continue to run about 10 to 15 C degrees below normal for the month of sept. in Alberta.
Oh, the humanity!
Think of the poor kale eaters, lugging their heavy loads home from the produce aisle in the grocery store, bending their backs in the hot blazing sun…
How did life on planet Earth make it for 3.5 billion years without human climate scientists to nanny it?
I would think that building thicker leaves would require the intake of even more CO2. Thicker leaves should also be more efficient at photosynthesis and the conversion of CO2 and H2O to organic matter. Their models are most likely wrong.
There is no real evidence that CO2 has any effect on climate and plenty of scientific rationale to support the idea that the climate sensitivity of CO2 is zero. The past models that they are using are all wrong so their conclusions are most likely all wrong as well.
“There is no real evidence that CO2 has any effect on climate and plenty of scientific rationale to support the idea that the climate sensitivity of CO2 is zero.”
Exactly! No evidence in the ancient records. No evidence in the 800k year ice core data. No evidence in the modern instrument record. Peer reviewed papers on Climate Sensitivity yield a 400:1 range, plus at least 30 papers that claim ZERO sensitivity and a few that show CO2 leads to climate cooling. Summary: no one has a clue. Yet look at how much research gets done on the foundation of the claims of high sensitivity. Social Justice Warriors and Climate Warriors would likely hit you with a bike lock if you tried to educate them on the truth.
Female plant to male plant: “Honey, does this CO2 make my leaves look fat?”
Ha! That’s good! I told my wife this one. She liked it too.
Reading this article, I’m terrified that I’ll end up wearing down my teeth when gnawing on my baby mesclun salad. If evolution really works, climate change will make us all look like beavers…