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Arthur T Knackerbracket has processed the following story:
In a study published in the Proceedings of the National Academy of Sciences, Professor Richard Thomas and alumnus Justin Mathias (BS Biology, '13 and Ph.D. Biology, '20) synthesized published tree ring studies. They found that increases in carbon dioxide in the atmosphere over the past century have caused an uptick in trees' water-use efficiency, the ratio of carbon dioxide taken up by photosynthesis to the water lost by transpiration -- the act of trees "breathing out" water vapor.
"This study really highlights the role of forests and their ecosystems in climate change," said Thomas, interim associate provost for graduate academic affairs. "We think of forests as providing ecosystem services. Those services can be a lot of different things -- recreation, timber, industry. We demonstrate how forests perform another important service: acting as sinks for carbon dioxide. Our research shows that forests consume large amounts of carbon dioxide globally. Without that, more carbon dioxide would go into the air and build up in the atmosphere even more than it already is, which could exacerbate climate change. Our work shows yet another important reason to preserve and maintain our forests and keep them healthy."
Previously, scientists have thought that trees were using water more efficiently over the past century through reduced stomatal conductance -- meaning trees were retaining more moisture when the pores on their leaves began closing slightly under rising levels of carbon dioxide.
However, following an analysis using carbon and oxygen isotopes in tree rings from 1901 to 2015 from 36 tree species at 84 sites around the world, the researchers found that in 83% of cases, the main driver of trees' increased water efficiency was increased photosynthesis -- they processed more carbon dioxide. Meanwhile, the stomatal conductance only drove increased efficiency 17% of the time. This reflects a major change in how trees' water efficiency has been explained in contrast to previous research.
Journal Reference:
Justin M. Mathias, Richard B. Thomas. Global tree intrinsic water use efficiency is enhanced by increased atmospheric CO2 and modulated by climate and plant functional types [$], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2014286118)
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @10:10AM (16 children)
This is an interesting turn of events. CO2 increasing water efficiency means that more CO2 will shrink the size of desolate areas that look like deserts. The trees will fill in a bit from the edges, exactly the opposite of the anti-CO2 fears. Groundwater will be retained more if it isn't taken up by trees.
I guess the next thing is to panic about running out of desert.
(Score: 3, Interesting) by Anonymous Coward on Wednesday February 10 2021, @10:43AM (13 children)
I don't think you have to panic about running out of deserts. Personally, I think the implications mentioned are a bit too optimistic to prevent desertification (which is far more complex and has more to do about the soil than the plants growing in that soil).
Also they turned around the narritive in the summary (and possibly the article itself), photosynthesis requires water to use the hydrogen in it to make sugars, so more photosynthesis (due to higher carbon levels), more water usage, less water to be evaporated (lower water potential in leaves, which in turn could cause stomatal closing), increased water efficiency. But nice to see this process confirmed.
From the abstract I got it was a meta-analysis, I hope they backed it up with some wet-lab data (even if not theirs). But hey, long live paywalls.
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @11:02AM
it's the national academy of sciences, so they can ask for money like any for-profit corporation, right?
(Score: 1) by shrewdsheep on Wednesday February 10 2021, @11:05AM (3 children)
More photosynthesis certainly uses more water in the process of fixation but wouldn't the amount be negligible? Large trees can evaporate several 100 liters per day, whereas fixated H20 would measure in say (most likely, maybe I'm wrong) a few kilograms at most.
(Score: 2) by c0lo on Wednesday February 10 2021, @11:52AM
TFA(stract) of TFA has the answer
40% is nothing to sneeze at.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 1, Informative) by Anonymous Coward on Wednesday February 10 2021, @01:34PM
Yes, you are correct about water transport being large IF available to the tree. As for the fixation, for every 40 grams/kilograms of CO2 being fixated a tree uses netto 18 grams/kilograms of water (brutto being the double), according to my old biology books. For how much an average tree fixates on a sunny day, I have no clue, but I guess these things depend on a lot of factors.
(Score: 4, Informative) by deimtee on Wednesday February 10 2021, @03:39PM
Do a BOTEC. :)
DDG says an 80 ft hardwood masses about 10 tons. Assume it is 20 years old. Double the mass to include the roots.
20,000kg / (365*20) = 2.7 kg/day.
That's a 20 year average, scaling linearly from 0, at 20 years it is probably about 5 kg of fixed carbon / day. *
Figures vary, but that 80 ft tree needs about 100 gallons a day (~ 400 litres).
Looks like around 1 or 2 % of the water is actually used to fix carbon, the rest is evaporated.
*(That doesn't account for any leaves it dropped over those 20 years, so you might want to double that again. Or not, those leaves would have rotted away and released the C again anyway.)
No problem is insoluble, but at Ksp = 2.943×10−25 Mercury Sulphide comes close.
(Score: 2) by c0lo on Wednesday February 10 2021, @11:44AM (7 children)
++
In other words: "once CO2 is no longer the bottleneck in trees growth, the next one is water availability. We are already seeing the trees retaining more of the water that, previously, was let to evaporate"
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @01:08PM (5 children)
I'm not sure if CO2 still isn't a bottleneck (and water is the next one), could very well be cellular/molecular processes that are the bottleneck now. You also have physical limits, e.g. diffusion/transport of CO2 into the intracellular spaces and cells, which is dependent on differences between concentration levels.
(Score: 2) by c0lo on Wednesday February 10 2021, @01:16PM
That may indeed be.
Yes, I know, everything has. Not gonna burn a tanker of petrol through a miniature engine in a day, no matter how much oxygen you have available.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 1) by khallow on Wednesday February 10 2021, @02:04PM
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @03:13PM (2 children)
The bottleneck is a more complex function of CO2 and water. The increase in CO2 means that plants can grow better across all water regimes, from swamp to desert. The reason why, changes from more CO2 available, to less H2O needed as things get drier.
(Score: 2) by c0lo on Wednesday February 10 2021, @04:57PM (1 child)
Trees... cellulose... polysaccharide... carbohydrates... each C with 2H and and O.
I reckon there's a limit for how less is that "H2O needed" and still have the plant growing better.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @06:44PM
I think you are parsing that wrong.
The "as things get drier" was referring to that end of the range not the individual conditions of a plant.
In dry climates, plants are still growing better than they were before (if they get the same amount of water) because the increase in CO2 means they need less water (to grow the same as before).
The vast majority of plant water use is simply evaporative loss during transpiration. Capturing CO2 more efficiently reduces water usage by far more than is used by the increased chemical fixation.
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @10:17PM
The bottleneck will be sunlight, once Crazy Bill Gates sprays shit in the atmosphere. Someone needs to look into that fucker. Nothing he does seems on the level.
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @08:28PM
Wow
So the climate change deniers go through every warning with a fine toothed comb for some bullshit reason why they don't have to care, but when a potential solution to some of climate changes problems is published they whinge about unnecessary panicing. Confirmation bias anyone?
Don't quit yer day job armchair einstein
(Score: 2) by jb on Thursday February 11 2021, @02:41AM
Nah, it's more fun to panic about running out of dessert...
(Score: 2) by bradley13 on Wednesday February 10 2021, @01:24PM (5 children)
Nature is dominated by negative feedback cycles, news at 11:00.
The Climate Catastrophe fans think a small rise in CO2 is going to turn Earth into the next Venus. This, despite the fact that CO2 has been much, much higher in the geological past. It's nice to finally see someone dare to publish a paper showing just one of the negative feedback cycles. We all know that CO2 is plant food - it's really no surprise that it is therefore forest food. Other negative feedback cycles include increased cloud cover (due to more moisture update). In fact, we are not all going to fry.
Of course, there's still no reason to run uncontrolled experiments on the only planet we have. Better stewardship would be a good thing. But climate change is a rather minor problem compared to mass extinctions being driven by human over-expansion and over-population. Something like the Half-Earth Project [half-earthproject.org] is more important than worrying about CO2 emissions.
Everyone is somebody else's weirdo.
(Score: 2, Insightful) by Anonymous Coward on Wednesday February 10 2021, @01:57PM (2 children)
The increase in CO2 (and resulting CH4 increase due to thawing permafrost) has been attributed to human growth and will result in mass extinctions (effects are already seen). So, please eleborate how something small, caused by humans, which results in the same effect as your statement is any different?
As for your "Climate Catastrophe fans", have you actually heard one saying that? Earth will not become a next Venus. As far as I know, most "Climate Catastrophe fans" are in the same group as the statement you made regarding mass extinctions being driven by climate change (caused by humans). The main issue of mass extinction caused by this is the fear that food webs might collapse and our own species enters the feedback loop (read: reduction of over-population). Add to this that the people who caused this (1st world) are better off than people not in that luxurious position (2nd/3rd world). Those "Climate Catastrophe fans" think that this is unfair.
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @03:25PM
They attribute anything to CO2, that doesn't mean anything. Same with deaths due to smoking.
(Score: 2) by PartTimeZombie on Wednesday February 10 2021, @08:54PM
Some people who have become fabulously wealthy from fossil fuels would like to continue to profit so they have spent some of their wealth on propaganda.
It has been fairly successful, especially in some parts of the United States.
(Score: 2) by legont on Wednesday February 10 2021, @03:22PM
Yes, indeed.
Meantime reduced pollution due to covid increased the temperatures in 2020.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL091805 [wiley.com]
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by Immerman on Thursday February 11 2021, @03:39PM
> CO2 has been much, much higher in the geological past
Yes it has - and at the time the Earth was in a hothouse state and tropical rainforests thrived at the poles. Over geological timescales, that's the most stable "normal" state for the planet, while we're currently in one of the most unstable states - an interglacial period that's lasted for all of human civilization (a paltry several thousand years), within an ice age that has lasted a modest 3 million years - still longer than the human species has existed.
Virtually everyone who knows what they're talking about is worried not about becoming a second Venus, but transitioning back to the "normal" hothouse state, probably much faster than ever before in the history of the planet. Because even taking that transition slow, it's typically devastating for life on Earth, causing mass extinctions as ecosystems collapse under the pressure of continuous change.
Very few people are worried we'll become a new Venus - we'd (probably) have to burn almost all the massive global coal reserves to put that option back on the table - but there was a time when the Earth *was* on a trajectory for runaway global warming, before plants evolved lignin to stiffen their stems into wood. It took 85 million years for rot to evolve the ability to digest wood, and so for 85 million years trees all over the world sucked CO2 out of the atmosphere and piled it up as rot-proof branches and tree-trunks on the forest floors, which eventually became coal. In the process, they averted the runaway global warming that had been happening, and preserved the planet's ability to support complex life.
(Score: 5, Funny) by Barenflimski on Wednesday February 10 2021, @02:55PM (2 children)
When you can't build your own Jurassic Park, return the earth to its prior state! Jeff Goldblum probably wouldn't approve, but who asked him.
If "The Little Dinosaur" is a window into the past, I'm looking forward to my 10^7th generational grand kids lives. Those little dinosaurs were just so cute and nice, and the leaves on the plants were HUGE.
For after all the millennia of extinction, aliens, famine and war, my future lineage will have a very large leaf to sleep under with their names on it!
Just remember one of the most important rules of life. If you haven't seen your karma come around to kick you in the ass, you haven't waited long enough.
(Score: 0) by Anonymous Coward on Thursday February 11 2021, @04:15AM (1 child)
Goodbye TP shortages!
(Score: 2) by Immerman on Thursday February 11 2021, @03:42PM
Unfortunately, then as now, when the time comes to use some leaves all you'll be able to find is poison oak or stinging nettles.
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @08:05PM (1 child)
More forest fires
More severe storms toppling trees
More invasive pests thriving in warming environment
(Score: 0) by Anonymous Coward on Wednesday February 10 2021, @10:20PM
If the climate of the region changes, the speices is no longer invasive I would say. Still there is way too many armchair climatologists everywhere. Most have never even seen the climate map of their state, let alone the world.