Higher Carbon Dioxide Levels May Result In Less Nutritious Food

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Most of us learned about photosynthesis when we were in high school. Plants use carbon dioxide and sunlight to make the food they need to grow. That means higher carbon dioxide levels should be good for plants, right? Absolutely, says Republican Congressman Lamar Smith of Texas. He is a firmly committed climate change denier who is the chairman of the House Committee on Science.

carbon dioxide and plants

Recently, he stated that we should not be concerned about rising carbon dioxide levels because CO2 is good for plants and anything that is good for plants is good for people. “A higher concentration of carbon dioxide in our atmosphere would aid photosynthesis, which in turn contributes to increased plant growth. This correlates to a greater volume of food production and better quality food,” he said.

Actually, Congressman, things are not that simple. Samuel Myers, a doctor turned climate researcher at Harvard University, leads the Planetary Health Alliance, a global research program that seeks to connect the dots between climate science and human health. He is deeply involved in understanding how carbon dioxide levels impact nutrition levels in plants, as Politico reports. He calls it part of a much larger picture about how changes in one area — like higher CO2 levels or drought — create ripple effects throughout an entire ecosystem.

First Study In 2014

In 2014, Myers and a team of researchers published the first large study on the topic in the scientific journal Nature. It examined crops grown in Japan, Australia, and the United States and found that as carbon dioxide levels increased, there was  a measurable decrease — about 8% on average — in the amount of protein, iron, and zinc contained in those crops.

The field has gotten very little attention from the scientific community. “This is the tip of the iceberg,” says Myers. “It’s been hard for us to get people to understand how many questions they should have.” The report claims, “The public health implications of global climate change are difficult to predict, and we expect many surprises. The finding that raising atmospheric CO2 lowers the nutritional value of crops is one such surprise that we can now better predict and prepare for.” In other words, the scientific community doesn’t know yet how much it doesn’t know.

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Lower Nutritional Value Widely Known

Changes in the nutritional value of fruits and vegetables have been noted by the scientific community for several years. A 2004 study found that everything from protein to calcium, iron, and vitamin C had declined significantly across most garden crops since 1950. The common assumption has been that farmers have selected to grow varieties of fruits and vegetables that are hardier or have higher yields or are resistant to certain pests and that is the cause of the decline.

But a person by the name of Irakli Loladze thinks higher carbon dioxide levels could be a contributing factor. In 1998, he was a Ph.D candidate in mathematics at Arizona State University. In addition to his specialty in math, Loladze also was fascinated by biology. He heard from others at ASU that something unexplained was happening in the biology labs.

The Food Chain Effect

If you have heard of the food chain, you know that zooplankton are pretty much at the bottom of it. They are microscopic animals that are an important part of the food supply for larger animals and they in turn feed on algae. Biologists at the university discovered they could significantly increase the growth rate of algae by exposing it to more light. If you are a gearhead, think of it as adding a turbocharger to an internal combustion engine.

The zooplankton now had more food than ever, but instead of thriving, they were literally starving. The researchers determined that the turbocharged algae had less nutritional value. It was the microscopic equivalent of junk food — loaded with extra sugar but short of actual nutrients. What if more carbon dioxide had a similar effect on plants as more light did on algae?

A Watershed Moment

“What struck me is that its application is wider,” Loladze says. Could the same problem affect grass and cows? What about rice and people? “It was kind of a watershed moment for me when I started thinking about human nutrition.” Ever since then, he has sought funding for more research on the question but ran into a hurdle unique to science. Organizations that funded mathematical research weren’t interested in biology and organizations that funded research on biology weren’t interested in mathematical studies.

Loladze pursued his research as he was able to, scouring the scientific literature for any studies that existed and find that almost none did. It was an area that simply had not attracted the attention of the scientific community. What data he was able to find all seemed to support his thesis. “Every leaf and every grass blade on earth makes more and more sugars as CO2 levels keep rising,” Loladze says. “We are witnessing the greatest injection of carbohydrates into the biosphere in human history — [an] injection that dilutes other nutrients in our food supply.”

We Are What We Eat

Much more research is needed to distinguish the effects of carbon dioxide from other factors, such as hybridization and what varieties of crops farmers choose to grow. What is not disputed is that the atmosphere today has much more carbon dioxide in it than it did in times past. Prior to the industrial revolution, the atmosphere had about 280 parts per million (ppm) of CO2. Today, that level is up over 400 ppm and is rising. Projections are that it will reach 550 ppm by mid-century — nearly twice as much as when the first tractors were introduced to the farming community.

One study published in the journal Environmental Health Perspectives earlier this year estimates that by the year 2050, 150 million people could be at risk for protein deficiency, particularly in countries like India and Bangladesh. The researchers suggest a loss of zinc could have negative health implications for another 138 million people because zinc is essential to maternal and infant health. In the US and other wealthy countries where access to food is not a problem, the higher glucose content of food could be a contributing factor to the onset of diabetes and other health issues connected to obesity.

Getting a start on the research needed is a problem. Kristie Ebi is a researcher at the University of Washington who has studied the connection between climate change and global health for two decades. “It’s a hidden issue,” she says. “The fact that my bread doesn’t have the micro-nutrients it did 20 years ago — how would you know?”

Is Goldenrod The Key?

The US Department of Agriculture is beginning to do research on the issue. Lewis Ziska, a plant physiologist at the Agricultural Research Service headquarters in Beltsville, Maryland, and his colleagues decided to eliminate the issue of plant selection and breeding by examining goldenrod, one of the favorites sources of food for bees and a plant that is not grown commercially. It turns out the Smithsonian Institute has an excellent collection of goldenrod dating back to 1842.

Ziska and his team found that the protein content of goldenrod today is about a third less than it was in the mid-19th century. It is common knowledge that something is having a negative impact on bee colonies. Ziska postulates that the reduced protein content of goldenrod may make it more difficult for bees to resist environmental changes and survive during the winter.

He worries that not enough research is taking place to determine the effects of elevated carbon dioxide levels on the plants humans rely on for food, especially since modifying crops to resist new environmental challenges can take up to 20 years to complete. “We’re falling behind in our ability to intercede and begin to use the traditional agricultural tools, like breeding, to compensate,” he says. “Right now it can take 15 to 20 years before we get from the laboratory to the field.”

First Large Carbon Dioxide Study Underway

Ziska and Loladze are collaborating with researchers in China, Japan, Australia, and in the US on a large study that will examine the effect of rising carbon dioxide levels and the nutritional profile of rice, one of humanity’s most important crops. Their study will also looks at vitamins in the plants student, an area of research that is almost nonexistent at the present time.

The elephant in the room, of course, it politics. Congressman Smith is just one of many members of Congress who have been suckled by the teachings (and money) of the far-flung Koch brothers empire. If any scientist dares suggest that climate change is anything but a boon to all humanity, the Koch-funded professional deniers will swing into action, finding any opportunity to discredit them and prove they are self-interested bozos drumming up controversy to keep the research dollars flowing their way.

The one thing Charles and David and their ilk don’t seem to understand is that no one will be able to pump billions of dollars in ill gotten gains into their wallets after fossil fuels have decimated the world’s population. Sales professionals say you can’t sell from an empty wagon, but it’s more basic than that. You can’t do business at all if there are no customers left alive to buy your products.

Source: Politico

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Steve Hanley

Steve writes about the interface between technology and sustainability from his home in Florida or anywhere else The Force may lead him. He is proud to be "woke" and doesn't really give a damn why the glass broke. He believes passionately in what Socrates said 3000 years ago: "The secret to change is to focus all of your energy not on fighting the old but on building the new." You can follow him on Substack and LinkedIn but not on Fakebook or any social media platforms controlled by narcissistic yahoos.

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