Sometimes I wonder if science hasn’t been infected with some sort of mass delusion about CO2. Watch this amazing video on CO2 and plant growth from CO2Science.org, then read below the claims made in this UC Davis press release.
Rising CO2 levels threaten crops and food quality
Rising levels of atmospheric carbon dioxide interfere with plants’ ability to convert nitrate into protein and could threaten food quality, according to a new study by researchers at the University of California, Davis.
The scientists suggest that, as global climate change intensifies, it will be critical for farmers to carefully manage nitrogen fertilization in order to prevent losses in crop productivity and quality.
The study, which examined the impact of increased carbon dioxide levels on wheat and the mustard plant Arabidopsis, will be published in the May 14 issue of the journal Science.
“Our findings suggest that scientists cannot examine the response of crops to global climate change simply in terms of rising carbon dioxide levels or higher temperatures,” said lead author Arnold Bloom, a professor in UC Davis’ Department of Plant Sciences.
“Instead, we must consider shifts in plant nitrogen use that will alter food quality and even pest control, as lower protein levels in plants will force both people and pests to consume more plant material to meet their nutritional requirements,” Bloom said.
Climate change, CO2 and agriculture
Historical records have documented that the concentration of carbon dioxide in Earth’s atmosphere has increased by 39 percent since 1800. If current projections hold true, the concentration will increase by an additional 40 to 140 percent by the end of the century.
This trend is of concern to agriculture because elevated atmospheric carbon dioxide levels have been shown to decrease the rates of photorespiration, the naturally occurring chemical process that combines oxygen with carbohydrates in plants.
At first, this reduction in photorespiration boosts photosynthesis, the complementary process by which plants grow by using sunlight to turn water and carbohydrates into chemical energy in the form of plant sugars. In time, however, the increase in the rate of photosynthesis tapers off as the plants adjust to increased atmospheric carbon dioxide, and plant growth slows.
The nitrogen connection
Nitrogen is the mineral element that plants and other living organisms require in the greatest quantity to survive and grow. Plants obtain most of their nitrogen from the soil and, in the moderate climates of the United States, absorb most of it through their roots in the form of nitrate. In plant tissues, those compounds are assimilated into organic nitrogen compounds, which have a major influence on the plant’s growth and productivity.
Earlier research has shown that when atmospheric carbon dioxide concentrations increase by 50 percent, the nitrogen status of plants declines significantly.
More specifically, findings from previous research by Bloom and colleagues suggested that elevated levels of carbon dioxide decreased photorespiration and inhibited nitrate assimilation in plant shoots.
New UC Davis study
In their most recent study, Bloom’s team examined the influence of elevated carbon dioxide levels and, in some cases, low atmospheric oxygen concentrations, on nitrate assimilation in wheat and Arabidopsis plants using five different methods.
Data from all five methods confirm that elevated levels of carbon dioxide inhibit nitrate assimilation in wheat and Arabidopsis plants. The researchers note that this effect could explain why earlier studies by other researchers have documented a 7.4-percent to 11-percent decrease in wheat grain protein and a 20-percent decrease in total Arabidopsis protein under elevated carbon dioxide levels.
“This indicates that as atmospheric carbon dioxide concentrations rise and nitrate assimilation in plant tissues diminishes, crops will become depleted in organic nitrogen compounds, including protein, and food quality will suffer,” Bloom said. “Increasing nitrogen fertilization might compensate for slower nitrate assimilation rates, but this might not be economically or environmentally feasible.”
He noted that farmers might be able to increase their use of nitrogen-rich ammonium fertilizers to ease the bottleneck of nitrate assimilation in crops but would have to carefully manage fertilizer applications to avoid toxic accumulations of ammonium in the plants.
To develop solutions for dealing with the impact of major increases in atmospheric carbon dioxide levels on crops, further research is needed on how plants assimilate nitrate and ammonium, Bloom said.
Working with Bloom on this study were Martin Burger of UC Davis’ Department of Land, Air and Water Resource; Jose Salvador Rubio Asensio of UC Davis’ Department of Plant Sciences; and Asaph B. Cousins, currently of the School of Biological Sciences at Washington State University.
Funding for this study was provided by the National Science Foundation, the U.S. Department of Agriculture and Spain’s Agencia Regional de Ciencia y Tecnologia.
About UC Davis
For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has 32,000 students, an annual research budget that exceeds $600 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Media contact(s):
- Arnold Bloom, Plant Sciences, (530) 752-1743, ajbloom@ucdavis.edu (He is away from campus until Wednesday but can be reached by e-mail.)
- Pat Bailey, UC Davis News Service, (530) 752-9843, pjbailey@ucdavis.edu
To develop solutions for dealing with the impact of major increases in atmospheric carbon dioxide levels on crops, further research is needed on how plants assimilate nitrate and ammonium, Bloom said.
Sir, you are a pseudo scientific prostitute and an idiot.
The decline in nutritional value per unit of plant mass is one of my few concerns with CO2. I’m not worried about agriculture as much as wildlife needing to consume more food to get enough nutrition.
Of course, maybe it doesn’t matter…that’s what natural selection is for…
Nick
In ‘Physiological plant ecology: ecophysiology and stress physiology of funcional groups’ (Springer, 2003), Walter Larcher writes:
“According to over 3000 scientific publications on the biology of CO2 effects, a broad spectrum of growth responses to CO2 enrichment exists. Since elevated CO2 often reduces the plants’ demands for other resources, CO2 effects on growth do not simply follow Liebig’s law of the minimum. Plants exposed to elevated CO2 need less enzymes (and thus lower quantities of leaf proteins and nitrogen), lose less water (can cope with less soil moisture and often operate at smaller stomata openings) and need less light (because of a shift in the light compensation point for photosynthesis) to reach the equivalent, or even higher photosynthetic rates than plants growing under control conditions with “normal” CO2 concentrations.”
Under ideal conditions, where there is no shortage of water, light, nutrients, trace elements etc, the benefit of doubling atmospheric CO2 may be 40%. However, where plants are resource limited, a doubling of CO2 can enhance growth of crops by over 100% in some cases. This is particularly important in regions of the world where the soil is poor for many reasons, since increasing atmospheric CO2 will enable crops to be grown efficiently where they currently cannot be grown without first improving the soil and irrigation.
In ‘Effect of Carbon Dioxide Concentration on Growth and Dry Matter Production of Crop Plants’ (Japan. Jour. Crop Sci, 1978) Imai and Murata showed that after 10 days of treatment with nitrogen at 350ppm and 1000ppm CO2 the dry weight (DW) of rice plants was as follows:
350ppm CO2, 30 mg nitrogen per plant DW = 835 mg per plant
350ppm CO2, 120 mg nitrogen per plant DW = 1,081 mg per plant
1000ppm CO2, 30 mg nitrogen per plant DW = 1,199 mg per plant
1000ppm CO2, 120 mg nitrogen per plant DW = 1,862 mg per plant
This demonstrates that at higher levels of atmospheric CO2, food crops have considerably lower requirements for fixed nitrogen for the same growth; alternatively, for the same nitrogen treatment they achieve considerably enhanced growth.
Higher levels of atmospheric CO2 lead to greater biological nitrogen fixation from the atmosphere, so less is required to be added as fertilizer. This is especially important in legumes, which are also able to improve their uptake and usage of phosphorus with increased CO2. Legume /bacterial symbiosis leading to nitrogen fixation is significantly increased at elevated CO2 levels (Reddy et al, 1989; Reardon et al, 1990). Philips et al (1976) demonstrated increased nitrogen fixation in peas, and Sherwood (1978) found the same in clover. A classic study by Hardy and Havelka (1975) showed that a tripling of atmospheric CO2 results in a six-fold increase in biological nitrogen fixation (from 75 to 425 kg per hectare) by rhizobial bacteria in nodules attached to the roots of soybeans.
“Nitrogen is the mineral element that plants and other living organisms require in the greatest quantity to survive and grow.”
As a living organism why do humans need nitrogen and what do I do with it in my body?
“Earlier research has shown that when atmospheric carbon dioxide concentrations increase by 50 percent, the nitrogen status of plants declines significantly.”
As to the above, when CO2 levels went from 180 ppm to 300 when coming out of an ice age are they saying that it was bad for plants? That the amount of CO2 during the Carboniforous Age was bad?
Something smells about this.
@Steveta_uk
Yeah, I can’t believe this article has even been given so much focus (judging by the number of comments) when it can’t even clearly elaborate the difference between photorespiration and photosythesis… great science…
I guess they have a dispute with these other folks who believe that carbon for plants is a good thing.
http://www.sciencedaily.com/releases/2007/10/071029172809.htm
You’re right. I should ignore one of the two most prestigious scientific journals in the world because of what some bloggers put up on YouTube. Good call.
In regards to the wanting $$ comments — scientists propose work in response to a specific solicitation. The few project proposals that are peer-reviewed to have the most scientific merit get funded. THEN they do the work. Scientists do NOT get money as some kind of a reward for getting answers that someone wants to hear.
Sylvan Wittwer (Professor emeritus at Michigan State University, who directed the Michigan Agricultural Experiment Station for 20 years and chaired the Board on Agriculture of the National Research Council) has remarked:
“There has been and still remains, a great reluctance on the part of many climatologists and ecologists, and especially environmentalists, to accept the concept that the rising level of atmospheric CO2 could be more beneficial than harmful for plant growth, food production, and the overall biosphere…Yet the scientific evidence is overwhelming.”
The likes of Al Gore have been promoting the hogwash in his books. Wittwer points out that of the HUNDREDS of scientific reports documenting the benefits, Al Gore carefully selected FIVE reports and a personal communication to emphasize possible negative aspects to enhanced CO2 on plants. Gore knew what he was doing, of course – he either deliberately rejected the facts, or gave instructions to researchers for his book only to cherry pick papers that support his alarmist agenda.
LearDog says:
May 14, 2010 at 4:03 am
So – this is science? “Let’s poison plants with CO2″ and then discover that there is an optimal level of nitrogen that goes with? And – the corker – need to lecture FARMERS (these are professionals, you eggheads) that they need to pay attention to their plants’ nitrogen needs?
Lord.
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LearDog, Didn’t you now a USDA manual tells USDA agents to address farmers at the 6th grade level????
http://salon.glenrose.net/?view=plink&id=3248
Talk about skewed data presentation. I find incredibly deficient agronomic and physiologic thought in every sentence of this press release. For example, wheat varies from ~8 – 12% protein (50%), associated with cultivar and species (hard red winter wheat vs soft white spring wheat for example). If protein content is reduced 10%, but total yield is improved 11% by elevated CO2, more protein per unit planted area is produced. Since higher CO2 increases yield greater than 10%, a 10% reduction in per plant nitrogen is not significant. We can also eliminate the “alledged” protein reduction in a selection process called genetics (D0h!). Farmers already are very careful with their “ammonium” input. It’s called profit motive. I haven’t read the actual paper yet, so it’s going to be worse than I thought. I’m just sick of this BS and don’t have the stomach to read it this morning, but this is probably going to be absolutely the worst paper I have seen in my 30 years of plant science. I want to puke my degrees up. There’s a reason it was published in Science. It couldn’t make it to the big leagues (Crop Science, Plant Physiology, Agronomy Journal, etc., etc., etc. etc.).
H.R. says:
May 14, 2010 at 4:11 am
“[…] as lower protein levels in plants will force both people and pests to consume more plant material to meet their nutritional requirements,” Bloom said. […]“
E-Z peazy! Eat more lizards to make up for the lost protien.
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Ok, that explains how the lizards are going to go extinct with all of this Gore bull warming.
Now could someone please explain (please bear with me as I never made it out of Mrs. Smith’s third grade class) how you can have a process like growing plants in a greenhouse that doesn’t produce waste?
If nothing else you have all of that heat produced to get rid of and wasn’t that money grubbing, overfeed, CO2 spewing, political hack worried about excess heat?
The crime is that your tax dollars are being squandered by government organizations that have become obsessed with CO2 and carbon based fuels. They have lost all comon sense and interest in honest science. The NSF and the National Academies have been taken over by radical environmentalists.
“Funding for this study was provided by the National Science Foundation, the U.S. Department of Agriculture and Spain’s Agencia Regional de Ciencia y Tecnologia.”
OceanTwo says:
May 14, 2010 at 4:30 am
“I guess the farmers are just sittin’ aroun’ on their butts waiting for them thar scientific types to tell ‘em how to farm…”
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Actually “the farmers are just sittin’ aroun’ on their butts waiting for them thar scientific types” to show up so they can fleece them in a poker game or by selling them over priced “organically grown” fruit and veggies. It is a favorite sport here in North Carolina, act dumb while fleecing the northern college professors, then laugh all the way to the bank. (I set up at a farmers market near Chapel Hill NC)
Jarmo says: (May 14, 2010 at 3:24 am):”Are they saying that protein content of plants absolutely decreases with higher CO2? Or, are they saying that the protein content of plants does not increase at the same rate as organic mass? Could not find a specific statement.”
In governmentspeak a decrease in rate of increase is labeled a decrease. So if plant X has a protein content of Y and you increase the plant growth to 2X but the protein content is less than 2Y, it will be called a decrease in protein content.
Now, if there is an actual protein decrease rather than just a decrease in rate of increase, simply eat more meat!
OT or not OT depending on how you look at it: the cover story on this week’s New Scientist is a hit-piece on “denialists” which treats climate-change “deniers” as being the same as Holocaust deniers and 9-11 “truthers”.
Darn it, that is why Adonai invented sheep and cows. They turn plants into protein.
I much more worried about dihydrogen monoxide. They are spraying it all over crops these days and measurable amounts are showing up in baby food!
When you add CO2 to the greenhouses I suppose you get rotten tomatoes or flippy floppy tomatoes. That must explain it. Yeah sure, when you remove one of the constraints to growth you will be exposed to another. Duh.
I knew that all those people who claimed that greenhouse growers were using 1,000 ppm were lying through their teeth.
Sounds like the rotten ice argument. With more CO2 you may get more of something but its all rotten.
Bill S says on May 14, 2010 at 5:23 am
Aren’t we always being told we should get more fibre in our diets?
1. The crop is NOT threatened
2 The yield is actually greatly increased
3 The robust increase in yield DOES NOT require a proportionate increase in watering.
4 The quality does not drop. They did claim to find a small increase in protein percentage. A large crop increase, protein increase but for example wheat would be 11% protein instead of 12% protein. They imply we will spend more time eating more food because of lower quality. That ONLY applies to a small extent to vegetarians with certain other restrictions in their diets.
5 These “ag scientists” are acting stupidly. Our herd of catle are fed plants. They do not eat meat. They turn carbohydrates into meat protein. Ruminants process rumen degradible protein. If it is too high, it is passed in the urine.
http://attra.ncat.org/attra-pub/PDF/ruminant.pdf
When scientists in the name of politics hijack science and add spin to the “story” or “reframe” the story as Joe Romm claims, it must be dealt with.
Action step:
Order the burger as a chees burger with bacon to offsett the dangerous drop in protein in the pickles and onions. (ooops, the research was about mustard. The mustard on the burger is lower quality because it is slightly lower protein)
@Don Keiller
The article you cited is from a journal committed to “the quickest possible peer review.”
“We are committed to rapid processing – from online submission using Manuscript Central, enabling the quickest possible peer review, through to the use of e-proofs
and then publication ‘as-ready’ via Early View.”
http://www.newphytologist.com/view/0/authors.html
Here is a conclusion from a different paper:
“In unfertilized ecosystems, microbial N immobilization enhances
acclimation of plant growth to elevated CO2 in the long-term. Therefore, increased soil C input and soil C sequestration under elevated CO2 can only be sustained in the long-term when additional nutrients are supplied.”
http://faculty.jsd.claremont.edu/emorhardt/159/pdfs/2007/2_8_07.pdf
There are many papers out there pointing in various directions. It is foolish to assume only the ones with results you like are the only relevant ones. We are changing the composition of our atmosphere. We are changing the chemistry in our oceans. We are changing our climate. Some of these changes may be positive, but one would have to be hopelessly naïve to assume all is benign.