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Dotz writes: "At the elevated levels of atmospheric carbon dioxide (CO2) anticipated by around 2050, crops that provide a large share of the global population with most of their dietary zinc and iron will have significantly reduced concentrations of those nutrients, according to a new study led by Harvard School of Public Health (HSPH)."

 (photo: EcoWatch)
(photo: EcoWatch)


Rising CO2 Levels Will Make Staple Crops Less Nutritious

By Todd Datz, EcoWatch

11 May 14

 

t the elevated levels of atmospheric carbon dioxide (CO2) anticipated by around 2050, crops that provide a large share of the global population with most of their dietary zinc and iron will have significantly reduced concentrations of those nutrients, according to a new study led by Harvard School of Public Health (HSPH). Given that an estimated 2 billion people suffer from zinc and iron deficiencies—resulting in a loss of 63 million life years annually from malnutrition—the reduction in these nutrients represents the most significant health threat ever shown to be associated with climate change.

“This study is the first to resolve the question of whether rising CO2 concentrations—which have been increasing steadily since the Industrial Revolution—threaten human nutrition,” said Samuel Myers, research scientist in the Department of Environmental Health at HSPH and the study’s lead author. The study appears online May 7 in Nature.

Some previous studies of crops grown in greenhouses and chambers at elevated CO2 had found nutrient reductions, but those studies were criticized for using artificial growing conditions. Experiments using free air carbon dioxide enrichment (FACE) technology became the gold standard as FACE allowed plants to be grown in open fields at elevated levels of CO2, but those prior studies had small sample sizes and have been inconclusive.

The researchers analyzed data involving 41 cultivars (genotypes) of grains and legumes from the C3 and C4 functional groups (plants that use C3 and C4 carbon fixation) from seven different FACE locations in Japan, Australia and the U.S. The level of CO2 across all seven sites was in the range of 546 to 586 parts per million (ppm). The researchers tested the nutrient concentrations of the edible portions of wheat and rice (C3 grains), maize and sorghum (C4 grains), and soybeans and field peas (C3 legumes).

The results showed a significant decrease in the concentrations of zinc, iron and protein in C3 grains. For example, zinc, iron and protein concentrations in wheat grains grown at the FACE sites were reduced by 9.3 percent, 5.1 percent, and 6.3 percent, respectively, compared with wheat grown at ambient CO2. Zinc and iron were also significantly reduced in legumes; protein was not.

The finding that C3 grains and legumes lost iron and zinc at elevated CO2 is significant. Myers and his colleagues estimate that 2 billion to 3 billion people around the world receive 70 percent or more of their dietary zinc and/or iron from C3 crops, particularly in the developing world, where deficiency of zinc and iron is already a major health concern.

C4 crops appeared to be less affected by higher CO2, which is consistent with underlying plant physiology, as C4 plants concentrate CO2 inside the cell for photosynthesis, and thus they might be expected to be less sensitive to extracellular changes in CO2 concentration.

The researchers were surprised to find that zinc and iron varied substantially across cultivars of rice. That finding suggests that there could be an opportunity to breed reduced sensitivity to the effect of elevated CO2 into crop cultivars in the future.

In addition to efforts to reduce CO2 emissions, breeding cultivars with reduced sensitivity to CO2, biofortification of crops with iron and zinc, and nutritional supplementation for populations most affected could all play a role in reducing the human health impacts of these changes, said Myers. “Humanity is conducting a global experiment by rapidly altering the environmental conditions on the only habitable planet we know. As this experiment unfolds, there will undoubtedly be many surprises. Finding out that rising CO2 threatens human nutrition is one such surprise,” Myers said.

Other HSPH authors include Antonella Zanobetti, Itai Kloog and Joel Schwartz.


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-5 # Malcolm 2014-05-11 10:30
This IS satire, right?
 
 
+5 # REDPILLED 2014-05-11 14:37
Only to deniers of catastrophic climate disaster and any others who don't give a damn about our grandchildren.
 
 
-4 # Malcolm 2014-05-11 15:24
That's very judgemental, RP. Also incorrect.
 
 
-5 # Malcolm 2014-05-11 10:56
CO2 increases may save our coasts!

http://www.sciforums.com/showthread.php?92136-More-CO2-Stimulates-Wetlands

"The team conducted their study for two years (2006 – 2007), during which they focused on the role that organic matter, both growing and decaying, plays on soil elevation in wetlands and the effect CO2 has on this process. Coastal wetlands must build upward through the accumulation of mineral and organic matter to maintain a constant elevation relative to water levels; otherwise, they will drown and disappear. ... "Our findings show that elevated CO2 stimulates plant productivity, particularly below ground, thereby boosting marsh surface elevation," said Adam Langley, the paper's lead author. Patrick Megonigal, the paper's corresponding author, added "We found that by stimulating root growth, thus raising a marsh's soil elevation, elevated CO2 may also increase the capacity for coastal wetlands to tolerate relative rises in sea level." Both scientists are ecologists at the Smithsonian Environmental Research Center in Edgewater, Md. ..."

To examine how CO2 may interact with other factors that will accompany sea-level rise, the authors also manipulated CO2, salinity and flooding in a companion greenhouse study. ... "Elevated CO2 doubled the short-term rate of elevation gain in our marsh."

BAD SCIENTISTS! Censor them! FIRE THEM! Cut off their grant money!
 
 
-4 # FDRva 2014-05-12 01:40
Are reports, like this, of rising CO2 levels--that are said to cause all the world's ills--designed to make some nominally green folks on Wall Street richer?
 

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