Quantcast
Food

Rising CO2 Levels Will Make Staple Crops Less Nutritious

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). 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.

Researchers tested the nutrient concentrations of the edible portions of wheat and rice — among other crops — and found a significant decrease in the concentrations of zinc, iron, and protein.

“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.

--------

YOU MIGHT ALSO LIKE

Maple Syrup Threatened by Climate Change

8 Foods That California's Drought Will Make More Costly

Climate Change Causes Spike in Coffee Prices 

--------

Show Comments ()
Sponsored
vimeo.com

Video Shows Oil Company's Plans to Drill Arctic From Artificial Island

The Liberty Project has posted a video about its proposal to build the nation's first oil production platform in federal waters in the Arctic.

The video was quietly uploaded two months ago and shows Hilcorp Alaska's plan to build an artificial gravel island and undersea pipeline for its offshore drilling project in the Beaufort Sea. Frankly speaking, the five-minute clip—with its all-American voiceover and electric guitar riffs—is something you'd expect from a pickup truck commercial.

Keep reading... Show less
www.youtube.com

Scientists Discover Sea Levels Rose in Sharp Bursts During Last Warming

By Rice University

Scientists from Rice University and Texas A&M University-Corpus Christi's Harte Research Institute for Gulf of Mexico Studies have discovered that Earth's sea level did not rise steadily but rather in sharp, punctuated bursts when the planet's glaciers melted during the period of global warming at the close of the last ice age. The researchers found fossil evidence in drowned reefs offshore Texas that showed sea level rose in several bursts ranging in length from a few decades to one century.

The findings appeared Wednesday in Nature Communications.

Keep reading... Show less
Gemasolar 15 MW Parabolic Power Plant in Spain / Greenpeace

Quitting Coal: New Global Survey Names the Companies, Countries and Cities

More than a quarter of the 1,675 companies that owned or developed coal-fired power capacity since 2010 have entirely left the coal power business, according to new research from CoalSwarm and Greenpeace. This represents nearly 370 large coal-fired power plants—enough to power around six United Kingdoms—and equivalent to nearly half a trillion dollars in assets retired or not developed.

While many generating companies go through this rapid makeover, the research also shows that a total of 23 countries, states and cities will have either phased out coal-fired power plants or set a timeline to do so by 2030.

Keep reading... Show less
Roderick Eime / Flickr / CC BY 2.0

New Evidence Suggests Ancient Egypt Was Brought Down By Volcanoes and Climate Change

Ancient Egypt is often described as an exotic place—pyramids, hieroglyphics, lavishly worshipped kings and queens.

But in many ways, it has a lot of parallels to modern life. It was an economically diverse, culturally vibrant and unequal place.

The millenniums-old society also struggled with a phenomenon that people today know all too well: climate change. And it may have ultimately led to the civilization's demise, according to a new paper by a team of researchers at Yale University.

The team of researchers studied the tail-end of ancient Egypt during the Ptolemaic dynasty between 305-30 BCE.

Keep reading... Show less
Sponsored
Portuguese youth plaintiffs, from left to right: Simão and Leonor; Cláudia, Martim and Mariana; André and Sofia. Global Legal Action Network

Kids Harmed by Portugal Fires Reach Key Crowdfunding Goal for Climate Lawsuit

As Portugal reels from its worst wildfires on record, seven Portuguese children have met an important crowdfunding goal for their major climate lawsuit against 47 European nations.

More than £20,000 ($26,400) was pledged by 589 people, allowing the Global Legal Action Network (GLAN)—the nonprofit coordinating the lawsuit—to identify and compile evidence to present to the European Court of Human Rights in Strasbourg, France. GLAN now has a new stretch target of £100,000.

Keep reading... Show less
Flying insects such as bees are important pollinators. Flickr / M I T C H Ǝ L L

German Nature Reserves Have Lost More Than 75% of Flying Insects

A new study published Wednesday in the journal PLOS ONE adds more evidence that insect populations around the globe are in perilous decline.

For the study, researchers from Radboud University in the Netherlands, alongside their German and English colleagues, measured the biomass of trapped flying insects at 63 nature preserves in Germany since 1989. They were shocked to discover that the total biomass decreased dramatically over the 27 years of the study, with a seasonal decline of 76 percent and mid-summer decline of 82 percent, when insect numbers tend to peak.

Keep reading... Show less
Sponsored
Politics

Pushing Toxic Chemicals and Climate Denial: The Dark Money-Funded Independent Women’s Forum

By Stacy Malkan

The Independent Women's Forum is a 501(c)(3) nonprofit that has taken money from tobacco and oil companies, partners with Monsanto, defends toxic chemicals in food and consumer products, denies climate science and argues against laws that would curb the power of corporations.

IWF began in 1991 as an effort to defend now Supreme Court Justice (and former Monsanto attorney) Clarence Thomas as he faced sexual harassment charges. The group now says it seeks to "improve the lives of Americans by increasing the number of women who value free markets and personal liberty."

Keep reading... Show less
Mladen Kostic / iStock

Toxic Toys? After Nine Years, a Ban on Harmful Chemicals Becomes Official

Phthalates are a particularly harmful type of chemical, used, among a range of other ways, to soften plastic in children's toys and products like pacifiers and teething rings. In response to mounting concern about the serious health impacts of phthalates—most notably, interference with hormone production and reproductive development in young children—Congress voted overwhelmingly in 2008 to outlaw the use of a few phthalates in these products and ordered the Consumer Product Safety Commission (CPSC) to assess the use of other types of the chemical in these products. After much delay, the CPSC voted 3–2 Wednesday to ban five additional types of phthalates in kids' toys and childcare products.

Keep reading... Show less
Sponsored

mail-copy

Get EcoWatch in your inbox