One sunny spring day in 1997, Irakli Loladze walked from the mathematics department at Arizona State University where he was doing his PhD, to the biology lab headed by professor James Elser. Experiments on zooplankton—very small animals that live in oceans and lakes—and algae, their food, would determine the rollercoaster ride of his research career for the next 20 years. He would hit rock bottom before soaring redemption would be his.

As Loladze explored the lab he learned that something strange was happening with zooplankton. Algae—primitive, chlorophyll-containing organisms that often paint the water green—grew faster when showered with light. This meant more food for zooplankton. However, abundant food didn’t make the zooplankton thrive. In fact, they grew slower after buffeting on plentiful algae. For Loladze, who is passionate about biology but trained as mathematician, it was “a paradoxical result”: Why was more food bad for zooplankton growth?

However, the elegance and simplicity of the underlying explanation caught his attention: as more light is shone on algae, it photosynthesises more carbon, which in turn increases the ratio of carbon to other nutrients in algae. Zooplankton gets all the carbon it wants from its food but not enough other essential nutrients. Starved of those nutrients, it stops growing or even dies.

“Hidden hunger” refers to deficiencies in micronutrients, including minerals like zinc, iron, iodine,  necessary for building the body through a process called anabolism, and protecting its immune system.

Elser co-founded, emerging at the time, the theory of “biological stoichiometry”, the study of the balance of energy and multiple chemical elements in living systems. It looks at cells, populations and ecosystems in terms of a few chemical elements essential to all life, instead of thousands of complex compounds. Professor Robert Sterner is the other co-founder.

The theory was a flashlight for Loladaze; it paved a path for him to understand the problem in mathematical terms. His findings over the years on the connection between rising carbon dioxide concentrations in the atmosphere and the decrease in essential minerals in food would profoundly challenge our understanding of hunger, malnutrition, and agricultural yields.



e’re malnourished when we’re not eating what is required. Hunger is when we don’t have enough calories (energy), which we get from macronutrients like carbohydrates, proteins and fats. Our bodies break down macronutrients by a process called catabolism.

“Hidden hunger” refers to deficiencies in micronutrients, including minerals like zinc, iron, iodine, and others which are necessary for building the body through a process called anabolism, and protecting its immune system. ​Hidden hunger stems from diets that are sufficient in calories but deficient in micronutrients—it may not be apparent in clinical syndromes. It’s hidden because these minerals are not as visible when we eat carbohydrates or fat; nor do we necessarily associate our loss of vitality with mineral deficits.

In India, we have both chronic hunger—amount of food intake not sufficient for dietary energy requirements lasting at least a year—and hidden hunger.

A World Bank report from 2012 details significant regional disparities in malnutrition: Sixty per cent of the burden of malnutrition is found in the low-income states of Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Rajasthan, and Uttar Pradesh. An additional 8-10 per cent of the burden is concentrated in specific geographical areas in the states of Andhra Pradesh and Maharashtra.

Wasting affected one in twelve (52 million) of all children under five years of age in 2016, more than half of whom live in Southern Asia.

Anaemia in women is overwhelming. A 2014 review study—“Anaemia ‘a silent killer’ among women in India: Present scenario”—using National Family Health Survey statistics reveals that every second Indian woman is anaemic and one in every five maternal deaths is directly due to anaemia.

Despite the widespread undernutrition in India, about 50.9 million people suffer from diabetes, and this figure is likely to go up to 80 million by 2025, making it the “Diabetes Capital” of the world, according to Diabetes Foundation (India). Thirty-seven per cent of urban south Asian Indians suffer from diabetes and pre-diabetes, it says.

According to a joint 2017 United Nations report—“The State of Food Security and Nutrition in the World”—global hunger is on the rise again, affecting 815 million people in 2016, or 11 per cent of the global population. This rise comes after steadily declining for over a decade. Thirty-eight million more people are undernourished compared to 2015. The report attributes the rise to war and “climate-related shocks”. However, hidden hunger affects many more people than hunger does with over 2 billion people deficient in one or another micronutrients.

In one disquieting message, the report says, “Wasting affected one in twelve (52 million) of all children under five years of age in 2016, more than half of whom (27.6 million) live in Southern Asia.”



oladze was also attracted to the zooplankton experiment because it offered him a potentially novel approach to studying the growth of populations. He knew from his maths training that researchers working with (population dynamics) mathematical models describing population changes tracked quantity but never allowed for quality.

Classical prey-predator models track the number or biomass of prey and predators. They look at populations as made of a single “building block,” while each prey or predator is a constituent of multiple “building blocks”—carbon,  nitrogen, phosphorus, sulphur, calcium, magnesium and others.

Loladze began wrestling maths and biology into two simple equations that captured the balance and ratio of chemical elements, carbon(C) and phosphorus (P). The C-to-P ratio represented the prey (algae) quality for zooplankton, because zooplankton is often phosphorus-limited in lakes and oceans. Phosphorus is critical for zooplankton. It is in the DNA and RNA of every organism but aquatic and many terrestrial systems often have little phosphorus available to them.

When light is increased, the C-to-P ratio in algae increases and zooplankton eat more C and less P. Fortunately, we usually get enough phosphorus with our food, but often experience a deficiency of many other elements: iron, iodine, zinc, calcium, magnesium, selenium, and chromium.

Loladze, with Elser, and his PhD adviser, mathematician Yang Kuang, published their paper—“Stoichiometry in producer-grazer systems: Linking energy flow with element cycling”—in the Bulletin of Mathematical Biology in 2000.

Launching from that study, Loladze began thinking more broadly about plants and herbivores because nothing in his model was specific to algae or zooplankton—it could have been any plant and any herbivore.

More light makes plants grown better. But there is another thing that makes plants grow more: an increase in carbon dioxide in the atmosphere, a reality of the post Industrial Revolution world. If more light increases photosynthesis and can cause carbohydrates (sugars and starch) to build up and minerals to crash, as happens with algae, does increasing carbon dioxide do the same to plants? Loladze asked himself. He knew that elevated levels of carbon dioxide, just like light, increases photosynthesis.

That’s how he began thinking about the effect of carbon dioxide on plants and what it entails for humans. He wanted to see how CO2 is contributing to the drop because this was the one global factor not associated with human nutrition. Other factors responsible for the nutritional decline were relatively well-known: breeding​ for higher yields and not for quality,​ and soil depletion.(The latter exacerbates the imbalance between rising CO2 in the air and decreasing nutrient levels in soil available to plants.)

He began worrying about people who rely heavily on plants to survive. What if rising CO2 is reducing the nutritional value of plants? Atmospheric carbon dioxide concentration was at 280 parts per million (ppm before the Industrial Revolution, and rose to 410 in last April. By 2050, scientists believe, the level could go up to 550 ppm and reach almost 900 ppm by the end of the century, one of the possible scenarios according to the US Environmental Protection Agency’s projections based on IPCC’s Special Report on Emissions Scenarios.

“A light bulb went off in my head, linking the effect of CO2 on plants to the quality of human nutrition,” he says.



ll life shares a set of chemical elements. Whether it is a virus—which is not considered a life form—bacteria, elephant, or human, they all require carbon, nitrogen, phosphorus and a few other elements. Life is a constant competition and trade-off for those elements.

When we lack even a single element, our capacity diminishes. Millions of children lack zinc, so growth is stunted, immune system compromised.

Plants build themselves out of just 16 chemical elements. Except for carbon and oxygen, they draw the others from the soil. We require about two dozen  trace nutrients like zinc, iodine, magnesium, calcium, sulphur, iron, selenium and so on for constructing our bodies. Most of these elements were created billions of years ago when stars spectacularly exploded at the end of their life cycles. These elements must be replenished every day, and for food, we mostly rely on plants. Plants are the foundation of human nutrition.

Since elements cannot be destroyed, they turn over in cycles. From soil and air they get into plants. Herbivores eat plants and elements enter their bodies. Predators eat herbivores. When predators die, they decompose and the elements return to the soil and air. There is, thus, a global trade in elements. More than 80 per cent of our calories and most of the elements in our bodies come from plants. By looking at those elements, biological stoichiometry can provide insights into how life works.

When we lack even a single element, our capacity diminishes greatly. Millions of children lack zinc, so their growth is stunted, their immune system compromised. They are more prone to pneumonia and other diseases. Lack of iodine leads to cretinism. Iron deficiency increases maternal mortality.

The problem is acute in many south, South Asian and Southeast Asian countries because the micronutrients come mostly from plants and many plants have low levels of these nutrients. For example, India and Bangladesh rely heavily on rice and a small set of vegetables and staples. The World Health Organization counts dietary micronutrient deficiency among the world’s top problems.



n 2001, Loladze finished his PhD and was accepted for a postdoctoral position at Princeton University. On his walks along Lake Carnegie at Princeton, he would look at the greenish water filled with algae and wonder how increasing CO2 was affecting it, and how it affected zooplankton feeding on it. He would look at the old trees, leaves rustling in the wind, and think how every tree, every leaf was making more sugars and starch due to rising CO2. The question obsessed him.

After his doctorate Loladze began conducting a rigorous thought experiment like a physicist, a thought experiment rooted in the balance of chemical elements, asking what would happen to the levels of minerals in plants grown under elevated carbon dioxide levels. Applying the principles from biological stoichiometry, Loladze arrived at the conclusion that the levels of minerals should generally drop in plant tissues.

To empirically prove his conclusion he had to get data. There are two ways to get it: either you generate it in experiments or you scour literature for it.

He emailed a hundred researchers who grew plants under elevated CO2 conditions with requests for collaborations. A few responded, but without funding Loladze could not analyse samples from those studies.

Then he started searching the literature on the effects of elevated carbon dioxide on crops and wild plants. He found very little about CO2 effect on elements in plants, except for nitrogen.

Ecologists have known since the 1990s that nitrogen drops at elevated CO2 levels. Humans, in fact, consume so much of it that we spend energy excreting it through urine. Nitrogen is very important for plant nutrition but does not limit human nutrition. For human nutrition, iron, zinc, and iodine are a primary cause of concern due to widespread deficiencies, but Loladze found not a single data point on iodine.

The study reported changes in element levels in rice grains: nitrogen dropped by 14 per cent, phosphorus by 5 per cent, iron by 17 per cent and zinc by 17 per cent.

He searched thousands of publications. He compiled a few available results from various experiments growing plants at elevated CO2: closed chambers, greenhouses, open-top chambers and Free-Air Carbon dioxide Enrichment (FACE) experiments. In FACE studies researchers grow plants in open fields with some plots having elevated CO2 (by pumping CO2 into the open air) and other plots just under ambient CO2. The data was limited and fragmented, and for many elements non-existent. It contained noise, so to speak.

Noise is a term researchers use to describe conflicting and highly variable data, which makes it hard to detect a clear signal if such is indeed present. For example, in some experiments, zinc went up; in others calcium came down; and so was the case with other elements.

Loladze found there was a consistent drop for almost every element when he combined data from multiple experiments but such data were available only for a few elements. Among thousands of publications he reviewed, he could find only one that studied the effect of elevated CO2 on the elements in rice—a crop that billions of people eat.

The study reported changes in element levels in rice grains: nitrogen dropped by 14 per cent, phosphorus by 5 per cent, iron by 17 per cent and zinc by 17 per cent but calcium increased. For wheat grains, Loladze found a few studies and it seemed that iron, zinc, magnesium, nitrogen, sulphur—all dropped but potassium did not. Convinced by the conclusions of his thought-experiment Loladze realised that the inconsistencies came from small sample sizes. Increasing sample sizes required more data but no more data were available in 2002. Peter Curtis, a professor at Ohio State University, told New Scientist in 2002 that Loladze is “working in a data vacuum.”

Somehow, researchers had missed linking rising CO2 to essential elements and human nutrition, and this was the reason so little data were published on the issue. It fell to Loladze to join the dots. He found it worrisome that over two billion people don’t get enough iron, or zinc, or iodine, and yet there is so little data about what rising carbon dioxide levels could do to those elements.



lmost 30 per cent of Indians suffer from a lack of macronutrients—carbs, fat, proteins—and, do not consume enough food. Forty per cent people lack adequate proteins. At least 50 per cent Indians are deficient in vitamins and micronutrients. Micronutrient deficiency in women and children below five is up to 70 per cent. Then, 10-20 per cent urban people are overweight. These numbers are from the National Nutrition Monitoring Bureau, part of the Hyderabad based National Institute of Nutrition (NIN) .

To paraphrase Swami Vivekananda, the poor don’t have food to eat, and what the rich eat is not food.

The NIN has been investigating the changing measures of nutritional status of people in 10 states since 1972, and every 10 years, it comes up with a report.

“When comparing 1972 to 2014, improvements are very marginal. Severe forms of under nutrition and starvation came down, but people are not eating right amount of what’s required,” says Sesikeran B., former director, NIN. Although salt is iodised, deficiencies in zinc, iron, and others persist on a massive scale.

Shweta Khandelwal, associate professor and senior research scientist at Public Health Foundation of India, Gurugram, echoes the crisis.“Micronutrient deficiencies are a huge problem across the nation—affecting rich and poor.” More than half the children in 10 out of 15 states are still anaemic according to National Family Health Survey (NFHS-4) for 2015-16.

Apart from the public distribution system, there are three major government-regulated programmes to address this crisis: integrated child development service (ICDS); midday meal scheme (MDM); National Food Security Act (NFSA).The ICDS provides take-home rations for pregnant women, iron-folic acid supplements for adolescent girls, pregnant and lactating women; the second one tries to provide nutritious cooked meals for kids.

Although the schemes are good, they reach only 30 to 40 per cent of beneficiaries, Sesikaran notes.

NIN conducts intervention studies and programmes that help people get the required amounts of macro and micronutrients and the data are passed on to the government to run its programmes. This year it published  “Indian Food Composition Tables (IFCT 2017)”, after a gap of 45 years. The tables “try to capture nutritional information of Indian food”.

The 12 tables give nutritional information on 151 different food components for 528 key foods.  They detail various contents of key foods that make up 80 per cent of the Indian diet, collected from regional composite samples from six geographical regions of the country.

“When you compare the latest one and earlier one, you see that nutrient values of several  foods came down considerably,” Sesikeran says.

Elevated CO2 helps plants grow more, while stuffing them with more carbohydrates. This means less of elements like calcium, zinc, and iron.

The problem doesn’t stop with malnutrition. “It’s much worse,” says Rajeswari Raina, professor at Shiv Nadar University, an expert on agriculture and the politics of knowledge and growth. Malnutrition is a phase while stunting is a condition which a child may not get out of. Child brain growth peaks between ages zero to five. “If you deny nutrition then, it affects brain growth, brain function, and capacity for thinking and cognition,” she says. This is, she adds, a failure of our agriculture.



lants require both light and CO2 to grow. They obtain CO2 from the atmosphere through small openings in leaf called stomata. In a process known as photosynthesis, they use CO2 and water, and with the energy of sunlight convert them to sugars and starch for their growth.

Photosynthesis is a complex process and scientists still study it. Lewis Ziska, a plant physiologist at the US Department of Agriculture (USDA) in Maryland, has studied CO2 effects on plants since the 1990s. He explains that there are two basic types of photosynthesis; one is referred to as “C3” because the first product is a three-carbon compound; the other is “C4” because the first product is a four-carbon compound. 

The C3 type of photosynthesis occurs in about 95 per cent of all plant species, and it is these species—wheat, rice, oat, barley, beans—that are likely to respond to more CO2. The other type of photosynthesis (C4) is already saturated or near-saturated at current levels (corn, millet) and is likely not to respond much to more CO2..(Approximately 3 per cent of all plant species).

Elevated CO2, like more light, kicks up photosynthesis, which helps plants grow more, while also stuffing them with more carbohydrates. This also means less of essential elements like calcium, zinc, and iron in plant tissues. Quantity and quality don’t always go hand-in-hand; they’re often inversely proportional. Plants are enormously flexible in their chemical makeup. They can store the nutrients at highly variable concentrations.


Irakli Loladze showers sugar and starch on vegetables to show how  rising carbon in the air is changing the nutrient profile of food. Photo: Vakhtangi Loladze

Moreover, it’s not that all minerals deplete evenly due to rising CO2. As plants absorb nutrients differently from the soil, they cannot be affected similarly. There should be some variability, a point Loladze emphasised in his 2002 thought experiment. Increased CO2 affects other aspects of plant physiology, apart from photosynthesis. It makes plant leaves lose less water, the effect called “reduced transpiration”, which, in turn, reduces mass flow of water in soil that brings mobile minerals such as calcium or sulphur towards plant roots, while leaving immobile minerals like phosphorus less affected. Loladze was able to logically deduce that increased CO2 changes mineral concentrations in plant tissues unevenly but with the overall tendency to decline.

Another mechanism, Loladze says, is diffusion. Nutrients “diffuse” in soil and can get into the vicinity of plants’ roots depending on the concentration levels. Plants transpire less water, more water remains in soil, making it wetter, which dilutes the mineral levels and can decrease the rate of diffusion. The complex interplay happens in every plant and leaf and root. So the overall picture is lower mineral concentrations in plant species and tissues. Loladze specifically mentions iron (Fe), iodine (I) and zinc (Zn) in his 2002 paper because these three elements are most lacking in our diet.



alf the people in the world already lack at some point in their lives or experience chronic deficiencies of micronutrients such as these elements. In India and other countries, green revolution crops may have increased yields, but tended to lower nutrients. Researchers assumed that plants and crops are nutrient-poor because we’ve been growing them for higher yields rather than for nutrition. For people relying on these crops, there is a chronic deficiency of essential minerals and vitamins. This hidden hunger arises from calorie-rich, nutrient-poor diets, a widespread problem.

Loladze’s insight about atmospheric carbon dioxide changing the very nature of food we eat and his analysis pushes the problem of hidden hunger to a different order of magnitude.

The paper, making an explicit link between increased carbon dioxide and human nutrition—“Rising CO2 and human nutrition: toward globally imbalanced plant stoichiometry?—was published in Trends in Ecology and Evolution in 2002. Even though he published in a leading ecological journal, he says, “I was burdened by the enormity of the problem and wanted rapidly to advance the issue.”



synthesis associating two distinct and important topics—rising CO2 and the quality of human nutrition—being at Princeton University, and publication in a leading journal, things looked good for someone born in Georgia in the erstwhile USSR. He had wanted to be a biologist but they didn’t have high schools that specialised in biology. Instead, they had schools focused on maths and physics. After graduating from a famous Georgia high school, the 42nd Physico-mathematical School in the capital Tbilisi he enrolled at Tbilisi State University, studying maths.

In those days, every young man had to go through mandatory military service and Loladze had to interrupt his studies. He was assigned a post in Lithuania, part of the USSR then and NATO now. He had to guard nuclear warheads. But Loladze found no joy in it and applied for a job to take care of 53 cows that pastured in green fields above the warheads underground (“perhaps, cows were used as a military disguise?”). He got the job and had to milk four cows twice a day. “It’s funny that they had nuclear warheads but not a single milking machine on the entire base.” It is while milking cows that he noticed the connection between milk yields and quality of the pasture.

As Loladze was finishing his studies, the Soviet Union collapsed. There was a civil war in Tbilisi: thugs, bullets flying, blackouts, fires, severe food shortages. History books belonged to dustbins. Soviet money became valueless.

But it turned out that Soviet maths education was strong and in demand worldwide. Loladze reckons it transcends political boundaries; whether you’re a communist or a capitalist, an integral is still an integral. He was excited and almost in disbelief to learn from an American relative that he could apply to US graduate schools, and they would pay for him to study for his PhD provided he did some maths teaching in exchange.  His close friends in Tbilisi didn’t believe him at first, but he convinced them, and they too applied to the US maths graduate schools and all got accepted. He was accepted by Arizona State University and later his parents immigrated to the US.

It was for him a miracle, leaving total chaos and multiple civil wars for a flourishing country leading the world of research, then getting his masters and PhD, then being accepted by the prestigious Princeton University, linking two global issues together and publishing in a top journal . The trajectory suggested that Loladze’s idea that touched every planteater on Earth and would lead to an active research area. But things went downhill soon.

Though no one could find anything logically wrong with his thought-experiment, people were sceptical of his idea. Many thought that since they had never heard of rising CO2 affecting the quality of food they eat, it must not be a big deal. One expert told Loladze that he was not going to find noticeable differences in the levels of elements, aside from nitrogen, in plants grown at elevated and ambient CO2 levels. Some scientists were even convinced that Loladze’s hypothesis would not pan out. They expected that plants would adapt to increasing CO2 levels, and try to protect their reproductive organs—grains and tubers—that people mostly rely on for nutrition. One “big shot” said, even if iron drops a little bit, people could get it by eating tiny amounts of dirt, which refers to geophagy, like elephants eating dirt. Princeton was not  sufficiently interested in Loladze’s idea to support its advancement.

However, there was a thin silver lining. Jann Conroy, who co-authored the only paper at the time on the effect of CO2 on rice grain quality, emailed Loladze from Australia to say that she was so excited to read his paper that she had to contact him, and supported his thesis, and wished him Godspeed.



fter finishing his postdoctoral work in Princeton in 2003, Loladze accepted a tenure track position at the mathematics department in the University of Nebraska, Lincoln, which had a reputation for agricultural research. He was teaching maths even while writing for funding.

The maths division rejected his proposal. They said the proposal had too much biology. Next year, he applied to the biology division, and they said the proposal had too much maths in it.

Loladze proposed in his grant applications to put his thought-experiment onto a solid mathematical framework and empirically test its conclusions by analysing samples from existing and ongoing experiments on elevated CO2 in plants. He even got preliminary approval from six FACE centres to share samples. Combining samples from several centres would have allowed him to obtain a much higher statistical power than individual studies could achieve and detect the signal.

However, the National Science Foundation’s maths division rejected his proposal. They said the proposal had too much biology. Then, next year, he applied to the biology division, and they said the proposal had too much maths in it. The year after one of the referees reviewing Loladze’s proposal wrote that he was afraid this important interdisciplinary proposal would fall through the cracks in the system. And it did. So Loladze, having no funding, continued collaborating with researchers on mathematical models of algae and zooplankton and co-authored several papers, but his heart was in revealing the impact of rising CO2 on the quality of plants, and what it could do to nutrition.

Until 2009, he had grant after grant rejected. Some researchers even published a paper saying they tested Loladze’s idea in rice fields and found no support for it. But Loladze knew they were off track because their sample size was only three and the noise masked the true signal in their experiments. Seeing that Loladze could not generate any funding, the university decided not to renew the contract. He became jobless at the worst time, in 2009—the US was going through the great recession. “I could not get even a lab technician’s job during the financial collapse,” he says.

Loladze thought that even without funding and a job he could still advance the issue if he collected enough data from published experiments. Unfortunately, the university also cut his access to the library and his request to restore the access went unanswered. Most of the papers Loladze needed to access were behind paywalls, with publishers requiring him to pay $10-$39 for each paper.

With two children to feed, he was struggling to survive. His unemployment benefits ran out and he went on food stamps. The thing with food stamps, Loladze observes, is that you start buying cheaper foods, cheaper peanut butter, cheaper cereals, cheaper cookies, and you start noticing that cheaper foods have more sugars and starch.

Ironically, he says, that as CO2 is globally increasing sugars and starch in plants, Big Food does the same to many of its products. Poor people in a rich country such as the US eat nutrient-poor but calorie-rich foods.

“Those years were nothing but disappointment, disappointment, disappointment,” he says. Memories of those hard years reflected in the conversation. His voice got heavier. Silent moments sliced the words.



n 2011, his former PhD adviser and ongoing collaborator, Professor Yang Kuang arranged for him to apply at the Catholic University of Daegu, South Korea, where he was accepted as a maths assistant professor. He continued collecting every possible data point from experiments on plants grown at ambient and elevated CO2 levels. He assembled practically all the data ever published about CO2 impact on minerals in plants. But in 2012, a large study came out that also analysed published data on CO2 impact on plant minerals and did not find clear declines. Some minerals increased in some plant tissues and plant groups, others decreased in other tissues. This would be devastating to Loladze’s idea.

But he knew that his thought experiment was logically correct, and something must have been wrong with the study. Loladze looked at it and found that the way authors obtained increases in the levels of minerals in plants growing under elevated CO2 was by using very small sample sizes. Only when sample sizes were small they reported increases. They confused the noise for the signal, Loladze says. Eventually, the authors found many errors in their study and retracted it.

The data Loladze assembled came from four continents (Europe, North America, Australia and Asia), from temperate and tropical regions, for staple crops and wild plants, for edible and non-edible tissues, and included measurements on 25 chemical elements and over 100 plant varieties. It was the largest dataset ever assembled on the impact of elevated CO2 on elements in plants. However, most of the individual papers didn’t show a clear pattern. In some papers two or three or four elements would go up, in some others one or two would drop down. Loladze attributed it to small sample size and noise.

He gives the analogy of going to a casino for these dips and rises, and variation of data: on average, everybody loses money playing in casinos. That’s the mathematical certainty. But when you play once or twice, you might win money. That’s what is happening with chemical elements. One or two specific elements might increase in a few samples but the overall trend is that plants are losing minerals because of rising CO2.

Another effect of elevated CO2 levels is on proteins, which strongly correlates with nitrogen. Daniel Taub of Southwestern University, in Georgetown, Texas, and colleagues did a meta-analysis of elevated CO2 on proteins in 2008.

Taub reports that protein concentrations decreased in wheat, rice and barley when grown at elevated CO2 by an average of about 10 per cent. There was a similar decrease for potato.

Taub teaches an undergraduate class called “global change biology”. In teaching the class about the effects of elevated CO2 around 2004, he mentioned that growth at elevated CO2 increases carbohydrate concentrations, and decreases nitrogen and protein concentrations in plant tissues. One student asked him how these changes would affect people on Atkin’s diet, a high-protein and low-carbohydrate weight-loss diet that was extremely popular in the US at that time. He had no specific answer, but invited her to work with him on learning how foods and diet could be affected by elevated CO2. She wound up as one of the authors on their 2008 meta-analysis publication on CO2 effects on food crop protein.

Taub reports that protein concentrations were decreased in grains such as wheat, rice and barley when grown at elevated CO2 by an average of about 10 per cent across all experiments. There was a similar decrease for potato. There was only a very small decrease for soybeans. A decrease in protein was seen in studies performed in different types of facilities, studies that measure protein in different ways, and studies under different soil and fertility treatments. The studies that they meta-analysed experimentally increased CO2 (by pumping from tanks) in various settings—small chambers, glasshouses, outdoor chambers, and in FACE facilities.

“So decreasing protein under elevated CO2 seems to be a robust finding, not dependent on growth conditions, and not an experimental artefact,” he says.

Most plants—wheat, barley, potato and rice—use C3 photosynthesis, which is strongly affected by atmospheric CO2. Some plants—crops such as maize, millets, sorghum—use C4 photosynthesis, which is not much affected by atmospheric CO2, and these C4 crops are likely not to be affected much in their protein content. 

So the effects will be seen most strongly in those populations that rely most on non-legume C3 grain and root crops for their dietary protein, Taub says.

Taub and his colleagues used Food and Agriculture Organization (FAO) data to calculate for every nation the percentage of human protein intake from C3 grains and root crops. Bangladesh is the nation in the world most dependent on these sources of protein, constituting 76.8 per cent of protein intake. Other countries with a great dependence on these sources include India (51.3 per cent) and Sri Lanka (51.6 per cent).

Although some people and some human populations get a high proportion of protein from animals, most people get most of their proteins from eating plants. Rising CO2 decreases protein in plants. As one of the most important human dietary needs, decreasing protein intake does have important effects on nutrition and health.

The severe form of protein deficiency has a special name—marasmus, which is a bit different from kwashiorkor caused by severe protein and some calorie deficit. (As the naming distinction between the two is not very clear, both marasmus and kwashiorkor can be used to describe protein deficiency.)

Protein energy malnutrition (PEM) is measured in terms of underweight (low weight for age), stunting (too short for their age) and wasting (too thin for their height). Studies independent of Taub’s have shown the severity of the problem.

A 1992 study published in The Indian Journal of Pediatrics, says, nearly 150 million children under 5 years in the world and 70–80 million in India suffer from PEM, nearly 20 million in the world and 4 million in India suffer from severe forms of PEM like marasmus, kwashiorkor and marasmic kwashiorkor.

According to UNICEF brochure, 2012—“Nutrition-The first two years are forever”—in India, 26 per cent of children under two years of age are wasted, 39 per cent are stunted and 82 per cent are anaemic, to a large extent because they were not fed age-appropriate complementary foods at the right time (i.e., after six months).

A 2014 study—“Protein energy malnutrition India: The plight of our under five children”— in the Journal of Family Medicine and Primary Care says: The prevalence of stunting among under five is 48 per cent and wasting is 19.8 per cent and with an underweight prevalence of 42.5 per cent, it is the highest in the world. 



s research shows, rising CO2 decreases both micronutrients and proteins in plants. These declines have specific impacts on food security. “If you rely on a single food source (rice),” Ziska says, “you are more likely to be affected by this decline than if you have a multiple food sources (wheat, rice, oats, plantain, etc.). 

Secondly, “mono-cultures, with a narrow set of genetics are more likely to be impacted than diversity. Diversity can represent multi-cropping, or multiple varieties, or more crop rotation. But as climate changes, having a single genetically uniform crop increases your susceptibility to extreme events.”

Irakli’s article is an instant masterpiece on the lasting CO2 impact on crop nutrient loss and its grave consequences for human health.

To mitigate the crisis of malnutrition, in India, the National Food Security Act 2013 promised cheap staples to Below Poverty Line (BPL) families. It also promised to include coarse grains like jowar and millets.

Sesikeran suggests that people must have access to the right kind of affordable food; fortify food with micronutrients; develop new varieties that can withstand adverse climatic conditions; grow more millets (they can withstand droughts and high temperatures); encourage people to eat more millets rather than refined rice and wheat flour.

Khandelwal says, as the National Food Security Act 2013 promised, “If the coarse grains are included in all states, it will be great. Even pulses should be included.”



s academic 2013-2014 was drawing to a close and his South Korea stint almost over, Loladze published a monumental meta-analysis of all the data he assembled on May 7 in eLife, a leading open-access biomedical journal, empirically proving the conclusions of his 2002 thought-experiment. On the same day, an international team headed by Harvard published a similar study in Nature, the results of which supported Loladze’s prediction. His analysis of the data he gathered for more than ten years revealed the “hidden shift”. The incontrovertible shift harkens back to his stoichiometric prediction in 2002.

Professor Christian Koerner at the University of Basel, reviewing Loladze’s 2014 paper for Faculty of 1000, called his global synthesis “a gem of lasting impact” with “significant implications for human well-being.” Kuang says he is struck by the volume, breath and quality of the data, the rigour of Loladze’s analysis.

“Irakli’s eLife article is an instant masterpiece on the gradual and lasting CO2 impact on crop nutrient loss and its grave consequences for human health. He came to his findings after spending his most productive 15 years by sifting through mountains of data sets scattered in various scientific journals without government or foundation support,” Kuang says. 

The meta-analysis based on 7,761 paired observations—one observation from ambient CO2, the other from elevated—covering more than 15,000 samples from the last 30 years, shows a drop of 8 per cent in essential elements like zinc, iron, calcium, and magnesium.

Loladze’s analysis also revealed why so many small-scale studies failed to reveal the shift: when sample sizes are small, there are very few significant changes in mineral concentrations. The noise masks the signal. But as sample sizes increase, unmistakeable, clear and powerful signals emerge that trump all the noise—practically every mineral essential for human nutrition drops in the tissues of plants grown under elevated CO2.

The important part of the dataset assembled by Loladze was data generated in India and Philippines. Plant physiologists from the Indian Agricultural Research Institute, New Delhi, published their work on berseem at elevated CO2 in 2003; on nutrients of wheat in 2004; on spinach and fenugreek in 2007; on Indian mustard in 2013.  All the findings show drops in essential elements, although there is some noise.

Another paper Loladze cited discussed the “bioavailability” of micronutrients, especially zinc and iron—not just declines (from the Indian Council of Agricultural Research centre for North Eastern Hill region, Umiam, 2011). “Bioavialabilty” is the amount actually available to humans via digestion and entering the circulation. For example, grains can contain a certain amount of iron, but a lot of it might not available due to other chemical substances in grains that can interfere with iron digestions. A 1997 study led by Ziska at  the International Rice Research Institute, Philippines, suggesting  quantitative and qualitative changes in rice supply are possible if both CO2 and air temperature (that is, greater than 34 degrees Celsius) continue to rise.

These data are important because  most of the CO2 experiments take place in industrial countries that are in temperate areas. However, most of the people who would be affected by declining crop quality live in subtropical and tropical areas.

Thanks to the data from India, Philippines and southern China, Loladze showed that CO2 lowers the quality of plants in both temperate and tropical regions.

The publication of his 2014 meta-analysis silenced critics and prompted the US government, for the first time, to formally acknowledge in its official report that rising CO2 levels lower the quality of important crop and most plant species. The White House released the report on April 4, 2016 and the effect of rising CO2 on crop quality is a key finding of the report. Loladze contributed to that part of the report. Lewis Ziksa, who co-led the relevant food chapter of the report, invited Loladze to collaborate on new projects.

Loladze, 47 and now an associate professor at Bryan College of Health Sciences in Lincoln, Nebraska, is working with Ziska and researchers in different countries, to better understand the effect of rising CO2 on rice and vitamins. He also started several collaborations across the globe to further advance the issue because the “hidden shift”, Loladze says, is global.

“Every time you eat any type of plant food, rice, potatoes, vegetables, fruits that means you’re going to get slightly more carbohydrates and slightly less minerals. It’s not a one-time thing. And it’s not some years away. It’s here and now. For the rest of your life. Every day. Every bite.”

(This is the second part of a series on farmers and farming, agriculture in a world facing climate change and how the interaction between government, agribusiness and the general economy affects the farmer.