High CO2 boosts plant respiration, potentially affecting climate and crops

Here’s something you don’t see everyday: a university sending out a press release showing the potential benefits on crop yields of elevated atmospheric CO2 levels. – Anthony

Public release date: 9-Feb-2009


Contact: Diana Yates



University of Illinois at Urbana-Champaign

High CO2 boosts plant respiration, potentially affecting climate and crops

The leaves of soybeans grown at the elevated carbon dioxide (CO2) levels predicted for the year 2050 respire more than those grown under current atmospheric conditions, researchers report, a finding that will help fine-tune climate models and could point to increased crop yields as CO2 levels rise. The study, from researchers at the University of Illinois and the U.S. Dept. of Agriculture, appears this week in the Proceedings of the National Academy of Sciences. Plants draw CO2 from the atmosphere and make sugars through the process of photosynthesis. But they also release some CO2 during respiration as they use the sugars to generate energy for self-maintenance and growth. How elevated CO2 affects plant respiration will therefore influence future food supplies and the extent to which plants can capture CO2 from the air and store it as carbon in their tissues. While there is broad agreement that higher atmospheric CO2 levels stimulate photosynthesis in C3 plants, such as soybean, no such consensus exists on how rising CO2 levels will affect plant respiration.

IMAGE: Andrew Leakey and assistants at work in the Soy FACE facility at Illinois. Click here for more information.

“There’s been a great deal of controversy about how plant respiration responds to elevated CO2,” said U. of I. plant biology professor Andrew Leakey, who led the study. “Some summary studies suggest it will go down by 18 percent, some suggest it won’t change, and some suggest it will increase as much as 11 percent.” Understanding how the respiratory pathway responds when plants are grown at elevated CO2 is key to reducing this uncertainty, Leakey said.

His team used microarrays, a genomic tool that can detect changes in the activity of thousands of genes at a time, to learn which genes in the high CO2 plants were being switched on at higher or lower levels than those of the soybeans grown at current CO2 levels. Rather than assessing plants grown in chambers in a greenhouse, as most studies have done, Leakey’s team made use of the Soybean Free Air Concentration Enrichment (Soy FACE) facility at Illinois. This open-air research lab can expose a soybean field to a variety of atmospheric CO2 levels – without isolating the plants from other environmental influences, such as rainfall, sunlight and insects. Some of the plants were exposed to atmospheric CO2 levels of 550 parts per million (ppm), the level predicted for the year 2050 if current trends continue. These were compared to plants grown at ambient CO2 levels (380 ppm).

The results were striking. At least 90 different genes coding the majority of enzymes in the cascade of chemical reactions that govern respiration were switched on (expressed) at higher levels in the soybeans grown at high CO2 levels. This explained how the plants were able to use the increased supply of sugars from stimulated photosynthesis under high CO2 conditions to produce energy, Leakey said. The rate of respiration increased 37 percent at the elevated CO2 levels. The enhanced respiration is likely to support greater transport of sugars from leaves to other growing parts of the plant, including the seeds, Leakey said. “The expression of over 600 genes was altered by elevated CO2 in total, which will help us to understand how the response is regulated and also hopefully produce crops that will perform better in the future,” he said.

IMAGE: Illinois plant biology professor Andrew Leakey led a team that discovered that soybean leaves speed up their metabolism in response to rising CO2. Click here for more information.



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Kum Dollison

Dang, I wish they had measured ambient temperature a few feet above the test plots.
Somebody tell them to “go back and do it again.”
REPLY: They probably have an agrimet station nearby, most ag experiment stations in the midwest do. – Anthony

Pamela Gray

Boy does this bring back memories. My ex had to write a paper on soybeans for his final senior class in the Crops and Soils department at Oregon State University. Problem was, he was a pointer pecker. Could only type with his pointer fingers. He was also (and still is) a bit dyslexic. So I agreed to type his paper. That was back when there was no such thing as computer cut and paste. I used scissors and glue. By the time I was done, I could have read that paper back to him verbatim without looking. It is still a fond memory.

Pamela Gray

OT, Anthony, what is that station in Wallowa County, Oregon that has not been surveyed yet? Is it in Wallowa? You want me to look at it?

Kum Dollison

REPLY: They probably have an agrimet station nearby, most ag experiment stations in the midwest do. – Anthony
Would most ag ex. stations have the soy FACE technology?

Craig Moore

Seems that rising CO2 is nature’s viagra for beanstalks.

The Beeville TX A&M Agrilife Research Center is a USHCN weather station.
And Anthony, I re-emailed Jeff re photos and he quickly responded that he has to fill in a hole that he had dug to fix a water leak, before he takes the pix.
Irrigation? Wet bulb?

Shawn Whelan

This might explain why huge tankers deliver CO2 to the greenhouses and then they pump it in those greenhouses, to make the plants grow larger. Would have been quicker and cheaper to ask a greenhouse farmer, they figured this out years ago.

Mike Bryant

Well, I thought that the science was settled and CO2 was good for nothing whatsoever. It seems that the more we know, the better CO2 is for life on earth. Too bad so many believe that the science is settled. I’m sure that we will soon hear that there are problems with this study.
Those who follow the science, instead of the money and politics, have known for a long time that increased CO2 increases and crop yields. This is more confirmation of the good that CO2 accomplishes.

Dave Dodd

Ummmm! Didn’t Idso, et al already cover this??? …maybe starting 40 of 50 years ago??? CO2 is GOOD for us!!!


This is another indication that plants that evolved when CO2 levels were higher grow better in CO2 rich air. Most of the plants on Earth today evolved when CO2 levels were about 5 times current levels. In fact, CO2 levels were at a record low before industrial activity began to replace atmospheric CO2 that had been sequestered in fossil fuel and the CO2 levels are now recovering to something closer to “normal” over geological time. Had we not begun releasing this CO2, it has been hypothesized that plant production would have begun to fall off and we would be facing a mass extinction of plant life on Earth.


Does this mean that CO2 levels can be verified with soybeans?

Bob Wood

I learned about photosynthesis way back when I was in grade school. It utilizes CO2 and gives of O2. Is it just being rediscovered!?

Ian Pringle

Not only soybeans but a study by Palanisamy in 1999 showed that as the CO2 content of the atmosphere rises Eucalyptus seedlings exhibit increased rates of photosynthesis even during times of water stress.
The study showed that CO2-induced increases in photosynthesis will likely lead to greater biomass production, even when soil moisture is low, as during drought conditions. (Palanisamy, K. 1999. Interactions of elevated CO2 concentration and drought stress on photosynthesis in Eucalyptus cladocalyx F. Muell. Photosynthetica 36: 635-638.) http://www.co2science.org/articles/V3/N9/B1.php
This study may have future implications for the terrible fires in SE Australia where Eucalyptus forests are the norm. Perhaps our increasing CO2 atmospheric concentrations will one day be blessed for the higher food and biomass production it will provide!


The “Greening Earth” crew has been all over this for 20 years, I think…they were blasted for being tools of the oil industry.


Tree cores aren’t much good as thermometers, but I bet they would be good for measuring ambient co2 content from a 1000 years ago.


This seems like a really complicated, expensive, and not easily interpreted substitute for just weighing the plants after a season growing in either normal or increased CO2.

“Understanding how the respiratory pathway responds when plants are grown at elevated CO2 is key to reducing this uncertainty, Leakey said.”
Knowledge reduces ignorance.


And they folded up their tent, I meant to add. As someone mentioned above, Idso’s have been doing this research for decades, too. The press release makes it seem original.

Why are these people always experimenting with the odious soya bean? If we want to turn into a world of tofu-sucking, raffia-wearing, flatulent tree-huggers, the soya bean is just the thing. Far better is to encourage a proper diet in which flatulence is mainly emitted in the open air by animals that go moo, oink and baa rather than by us in our hermetically-sealed and insulated living rooms. I hate to think of the effect it has on those new twisty light bulbs that shed hardly any light but do so for decades.
You science people should encourage your fellows to do these tests on good sturdy potatoes, carrots and, if they have to, the occasional cabbage or asparagus. Concentrating on the soya bean sets a very poor example to children. There’s quite enough hippification and lentilisation going on already without adding to the poison.
REPLY: Soybeans are more than tofu, they are also a major source of a variety of industrial uses and derivatives. Being traded in future exchanges like the Chicago Board of Trade, it is not simply the “hippie food” you imagine it to be. – Anthony

Graeme Rodaughan

It’s pretty obvious to me that rising CO2 levels will result in catastrophic plant growth resulting in the violent intrusion of hyperbolic plants into cities, we won’t be able to cope with rampant plants over-running us all…
Humans will have to migrate to small pockets of available habitation to preserve what’s left of civilization…
The only hope is to stop burning fossil fuels immediately…
Oh dang – I forgot that I’m not an alarmist…

Ian Pringle

More recently, a group of scientists has set up one of the largest climate change experiments in Australia. They’re trying to mimic conditions trees will face in the next 50 years. By housing trees in gigantic chambers with elevated CO2 levels, the scientists are hoping to measure how they’ll grow in their new environment.
They chose to use eucalypts in their experiments because Eucalyptus is the most important genus in Australia, and is probably most likely to be representative of how trees in Australia will respond to future climate change.
Some of the preliminary studies have indicated that the trees are responding positively… “They’re growing at about 30% or 40% more than plants exposed to ambient CO2” http://www.abc.net.au/rn/scienceshow/stories/2007/2001966.htm

Ed Zuiderwijk

They use schrubbed industrial flue gasses with elevated CO2 content in the greenhouses in Holland. Produces mighty big juicy tomatoes!

Now, wait just a minute! If higher CO2 levels increase plant growth, then will falling CO2 levels decrease them? Someone, please phone Arnold, our Governator of Kahl-ee-fohn-ya. He has the state embarked on a deadly path, it seems, through AB 32 aka Global Warming Solutions Act of 2006. In it, CO2 will (note, that is SHALL) be reduced 30 percent by 2020! And furthermore, it SHALL be reduced another 80 percent by 2050!
Sound the Alarm! Our California trees, grass, shrubs, and agriculture will all die off from a lack of CO2!
Oh wait. What’s that I hear? In a sidebar, I was just informed that plants also need sunlight and water and nutrients to grow.
Well, there is plenty of sunshine, and lots of BS (of all kinds), but in California we don’t have enough water to grow stuff, anyway… never mind!
And to FatBigot, you are so correct in your analysis of soy products. It also appears they suppress testosterone, which could be a slight problem.
Roger E. Sowell
Marina del Rey, California

Kum Dollison

We know that plants strive to maintain a constant temperature, year-round. Vegetation has to have a “cooling” effect (in summer) on the atmosphere. Bigger plants would have a Greater cooling effect. The question is, “Is it enough to effect the atmosphere?


Wow. We are almost back to 7th Grade Science. Wonderful. Shouldn’t this be classified?


carlbrannen (20:53:31) : This seems like a really complicated, expensive, and not easily interpreted substitute for just weighing the plants after a season growing in either normal or increased CO2.
Well, yes, but,… There is some value to all the genetic testing they did. It provides a very strong statement that the metabolism is on ‘snail pace’ at present CO2 levels and is just waiting for some CO2 juice to turn on all the machinery. And you get this with a clear genetic activity profile across the whole metabolism profile. Very nice.
Consider the alternative: If it had been one or two genes that coded for, oh, sugar, you could make the case that the plant was being opportunistic and just storing away some sugar for future CO2 needs. You could say that higher CO2 wasn’t ‘normal’ or ‘better’, just available for a paranoid plant to put in the bunker. When the whole genome is kicking on, you can’t deny it: That is One Happy Plant! and it’s using the extra CO2 to “Kick it up a notch: BAM!” across the whole lifestyle.
FatBigot (21:12:52) : Why are these people always experimenting with the odious soya bean? If we want to turn into a world of tofu-sucking, […] Far better is to encourage a proper diet in which flatulence is mainly emitted in the open air by animals that go moo, oink and baa …
Don’t hang around farms much, eh?
Almost no soy ends up in tofu. Most of it goes into “moo, oink” & cluck. (Baa mostly gets grass…) Now the soy I like most goes into “Clackty Clakity CLAK CLAk Vroooom” (my soy oil powered bioDiesel sucking Mercedes Full Sized Sedan or my Mercedes Turbo Diesel Full Sized Wagon). A tiny little bit is used in my cooking oil in which the oink, cluck and the occasional ‘splash’ gets fried and some goes into making the corn bread that goes with it and, via the cow, the butter (real stuff, margarine is crud) that goes on it… And a lot is in the mayo that is used to make the potato salad, macaroni salad, and a big dollop goes with the avocado in the guacamole …
So just take a look at Purina Cow Chow, Pig Chow, Chicken mash, heck, even Trout Chow and you will see lots of soy beans and corn.
I’d have guessed Chow : tofu was at least 1000 : 1 but these folks:
Say it’s about 100:1 (1% tofu) but they also say most of the tofu is exported … tofu doesn’t sell all that much in the U.S.A.
So next time you sit down for that big thick rack of BBQ ribs, with macaroni salad, and chips with avocado / guacamole dip, thank the soy bean growers. Especially if you get to the restaurant driving a Diesel Truck on bioDiesel instead of OPEC crack.
See, you too can appreciate the ‘green soya bean’ 😉
Graeme Rodaughan (21:18:12) : It’s pretty obvious to me that rising CO2 levels will result in catastrophic plant growth resulting in the violent intrusion of hyperbolic plants into cities,
My God Man! I think you’re onto something! The article said a 37% increase! Plot that as an exponential growth and the world is doomed! DOOMED! We’ll be overrun with soy beans and grass so fast there is no hope! I can only see one way out: We need to start an immediate program of “Bunny Offsets”. Each person can send me $100/year for each bunny rabbit to be released into the wide in their name. This will allow them to avoid the mandatory TOFU allotment that all others will be required to eat as part of the “Cut and Trim” program. 😉


FatBigot (21:12:52) : wrote
You science people should encourage your fellows to do these tests on good sturdy potatoes, carrots and, if they have to, the occasional cabbage or asparagus.
What about Brussels sprouts then?? I bet you flat earth-believing, creationist skeptic bigots haven’t calculated the carbon footprint balance associated with those capitalist agents of the devil, have you? They have been shown conclusively, in peer-reviewed studies, to assimilate excess anthropogenic, atmospheric carbon dioxide and through both bacterial and anatomical positive forcing mechanisms, to expel into the atmosphere the even more potent GHG, methane, in prodigious quantities.
They should be banned immediately. Validated models have both demonstrated and shown demonstrably the positive feedback effects of methane production by sprout-consuming anthropogenic human beings. In fact, using a really, really validated model, the data was shown to be statistically significant to four decimal places, thereby clearly validating the already validated model. The study was published in a very peer-reviewed journal, the highly prestigious “Journal of Really Validated Models”.
The consensus-validated results of the International Brussels sprouts (BS) study are fully and demonstrably consistent with validated consensus IPCC models showing that the enormously massive loss of sea ice in the Arctic is directly proportional to the consumption of BS by inhabitants of the Northern Hemisphere.

FatBigot you are a funny guy. I tend to aggree with you. In addition to your logic, animals tast sooooo good.


Given that plants are green so that they can metabolise CO2.
Is it not a little ironic that the ‘greens’ hate the stuff so much ?


Graeme, My thoughts exactly. Expect a new disaster movie, “Attack of the killer soybeans” at a theater near you.

Leon Brozyna

Who’d a thunk — driving an SUV is Green or firing up a fossil fuel burning power plant is Green. This is similar to a story covered a few months back on these very pages:
Wait! I know how the AGW folk can stop this Green movement. All the CO2 is causing plants to become obese. It’s a plant obesity epidemic! It’s going to destroy the planet! Gaia must be saved.


The British Botanist and Environmental warrior and anti global warmist has been saying that CO2 is good for plants for years now


Heck I always wondered why the tunnel house vegetable growers here in New Zealand pumped copious amounts of CO2 into their enclosed environments.

Colin Wernham

From the project outline


I read about research on elevated CO2 in corn back in the late 1960’s. They were working with 1000ppm and 2000 ppm in sealed greenhouses… The results showed elevated, beneficial growth and grain production. This was part of research on increasing grain production. They wanted to introduce CO2 into corn fields as atmospheric “fertilizer”.
This is one of the reasons I stopped believing this “CO2 is bad” foolishness over 40 years ago.

Terry Ward

CO2 is good for us. Hold the front page.
Anyone willing to bet on the following?
There will be the same level of sustained publicity, following a statement from some future senior scientist that anyone that previously claimed that “CO2 producers should be prosecuted” should themselves be the subjects of litigation, as there was when “the world’s top climate scientist” stated such errant nonsense.
A (even if it is just the one) politician will make a detailed, prolonged public apology and explanation as to why they were suckered into creating legislation on the back of an alarmist agenda created from falsehoods.
Al Gore will be asked to return his Nobel and sci-fi prizes.
(sarcasm off)
Plant growth, individually, entirely and daily, causes global cooling.
(betting ends)
Here be monsters (courtesy of Erl Happ);
“The atmosphere does not store warmth. Above 700hPa it has returned to base temperature after each warming episode between 1948 and 2008. It is the sea that stores warmth.”
“Cooling of the stratosphere is not due to greenhouse gas warming of the troposphere. There is no temperature change in the lower troposphere except very close to the warmer ocean. Cooling of the stratosphere is due to ozone loss associated with surface warming.”
Recommended reading in my humble opinion.

Ian Pringle, unfortunately the Eucalypt is an incendiary device – it explodes in flames well in advance of the fire front, because of the alcohols etc in the leaves.
The poor old gum tree is the culprit, as to why you cannot out-run or out-drive a proper Australian bushfire – the fire-front of exploding Eucalyptus trees travels at up to 100 Km per hour, depending upon wind.
If you are really, really lucky, the fire-front (and bio-fuel conflagration) will rip by you so quickly, that the fire is gone down the valley in a few seconds. However, it is the incredibly intense heat (and of course embers sucked by cyclonic winds under eaves and into roof-spaces) that starts the fires in residences, and unfortunately kills people.
A very sad time for my country.

Mike McMillan

Here’s a press release from a 3 yr Stanford study –
High carbon dioxide levels can retard plant growth, study reveals
Of course, the title is a little misleading (natch). You read the article and it turns out CO2 in combo with other items increased plant growth by Only 40% .
A few decades ago, the global warming of the moment was called the “Population Bomb.” The earth would never be able to feed the billions of new humans expected. Well, the billions have arrived, and lo, we’re feeding them. I wish I could say it were due to advanced genetically engineered plants varieties, but the Luddite lawyers have GM crops like Golden Rice all bottled up.
The explanation for the approximately 15% increase in crop yield is the increased CO2 available to the plants. We can expect increases all the way up to 1000 ppmv. Here’s an Ontario, Canada govt paper on greenhouse CO2 enrichment.
The AGW community is totally blind to this truly life-and-death issue.

Terry Ward

There is agenda at play even here.
Soy, the way it is produced, processed and consumed by the majority of humans, is not good in any regard whatsoever. Worse are the claims made in praise of it. It is just about useful for animal feed, but if I ruled the world it wouldn’t even be allowed for that purpose.
Hemp seed on the other hand…….,

Robert Bateman

Did it ever occur to one that the AGW crowd is out to extinct us? They want to take all the CO2 out of the air so that agriculture will fail and so will Earth’s population. Then, having CO2 stored exclusively for themselves, they will release it so that they can live in the new Garden of Eden without us.

Bill McClure

Nice to see research related to CO2 that doesn’t have the typical global warming disclamer.

Artificial CO2 generation has long been used in agriculture to promote growth at times of low ambient CO2 levels and a quick look at this web page can be quite informative http://www.gas-plants.com/co2-generator.html
All encouragment, in my opinion, should be for promoting CO2 as a beneficial gas rather than the evil toxic devil that seems to be the model for the media.
Witness the UK ITN’s News at Ten last night in a report of the horrific bush fires in Australia. They callously seized the opportunity to inform us that ” Because of unprecedented high levels of CO2 in the atmosphere, the trees around Victoria have grown at a rapid and unchecked rate and provided the neccessary fuel for the local bush fires ” This is just stupid, unthinking and irresponsible journalism.

Mike McMillan

E.M.Smith (22:26:34) :
Don’t hang around farms much, eh?
Almost no soy ends up in tofu. Most of it goes into “moo, oink” & cluck. . . . So just take a look at Purina Cow Chow, Pig Chow, Chicken mash, heck, even Trout Chow and you will see lots of soy beans and corn.

Hi again, E.M. I’ve hung around farms and cows enough that the periodic terrorist anthrax scares don’t apply to me. I know Purina makes those Chows, but other than Trout Chow (or Catfish Chow), farmers would go broke if they tried to raise a herd on them. Starter feed, maybe, but most everything in the barnyard gets homegrown corn, cobs and all through the grinder.
We raise a lot of ‘beans’ in the Midwest, but I think (no citation) most of it goes to feed hungry Asians (not as tofu, please), gets processed into yummy ‘texturized vegetable protein”, or goes to the ADM chemical plant where they make car bodies, tank armor, and other plastical wonders of modern science.
I bought some toasted soy ‘nuts’ at the grocery the other day. Toasty, crunchy, oily, no flavor. Won’t buy more.
One consideration that ought to cheer up the greens, is that the CO2 rise is producing more food for the same energy input, with no increase in CO2 emissions.
Terry Ward (01:41:28) :
We get some wild marijuana in the fields here and there. The cows eat the buds and leaves, but leave the stems.

Roger Knights

OT, but worth noting for the record, here are a couple of recent stories.
1. “Harvard’s Holdren Wields Oscar-Worthy Climate Pitch for Obama
Headline (Bloomberg): “John Holdren, the Harvard University physicist who helped Al Gore earn an Academy Award.”
“Holdren’s dire predictions about global warming, illustrated in riveting charts and graphs, helped ex-Vice President Gore win an Oscar for his 2006 documentary, “An Inconvenient Truth.” Holdren also helped persuade Ford Motor Co. and ConocoPhillips Co. executives to accept that climate change caused by gas emissions threatened to raise sea levels and harm crops. His slide presentations pop up frequently in other people’s speeches.
“At age 64, Holdren now is taking on his toughest assignment: getting the American public and Congress to curb fossil fuel use. Barack Obama has named Holdren as assistant to the president for science and technology as well as director of the Office of Science and Technology Policy, a post for which he will face a Senate confirmation hearing on Feb 12.
“The White House “is the place where he ought to be right now, trying to save the world,” said Paul Ehrlich, …”
2. “Antarctic Bulge could Flood Washington” (from New Scientist)

Mark N

At last, thank you. The basics of photosynthesis. We’d all be dead without CO2.


FatBigot (21:12:52) :
“Why are these people always experimenting with the odious soya bean?”
To study this, potato plants (Solanum tuberosum L.) cultivars Norland’, Russet Burbank’, and Denali’ were grown in controlled-environment rooms at different levels of CO2 and irradiance.


E.M. Smith:
“We need to start an immediate program of “Bunny Offsets”. Each person can send me $100/year for each bunny rabbit to be released into the wide in their name.”
E.M….taking your lead from Al? Getting in on the ground floor?…building a “bunny offset trading market” all in the name of CO2-enhancement?
Your true colors finally show!…you…you…evildoer, you!
On the other hand…rabbits are quite tasty ;*)
(Hey…someone had to do it…)


The genetic basis of this study points out that plants have probably evolved (over a very long time) the ability to adapt (over a very short period) to everchanging low and high CO2 global regimes.
Hence temperature proxies based on yearly plant growth are maybe more unreliable than originally thought, whilst highlighting that plants are probably more robust in dealing with climate change.
Further if adaption over short period is one of the natural ways for plants to deal with climate change, then it points that animal life may have the genetic facility to do so as well.

Jim Turner

On the ITN evening news last night (UK), the science editor did a small piece explaining why the Australian bush fires are so bad. I had expected that ‘global warming’ might get a mention as the culprit for the above average temperatures and drought, but no.
Then he made the point that increased CO2 causes increased plant growth, which has made the bush denser and hence the fires more intense. It’s easy to see where this will go – another bad thing about CO2. The answer would seem to me to be some sort of forestry management. Irrespective of CO2 levels, this would seem to be common sense if you are going to build towns in proximity to woodland that is prone to burning.
While on the subject, can I offer my greatest sympathy to any Aussie readers who have lost their homes, property or friends and relatives in this ongoing tragedy.


Well said Kaboom. And if you look at some of the pictures of the fire damage, you will see the front of vehicles burnt out, while the rear is untouched.
Green lobbyists won. They managed to get their foolish laws pased so that fire fuel cannot be cleared. Fire breaks could not be created in the name of “green environmentalism”. Aboriginals knew and know how to manage this land, by fire.