Food security crisis: Rising CO2 to reduce global nutrient availability, study warns

19 Jul 2019 --- Climate change and rising CO2 levels could significantly reduce the availability of nutrients over the next 30 years, according to new research published in Lancet Planetary Health. The impacts of climate change and CO2 are estimated to reduce growth in global per capita nutrient availability of protein, iron, and zinc by 19.5 percent, 14.4 percent, and 14.6 percent, respectively. The effects will be felt more strongly in regions comprised of low- and middle-income countries where levels of undernutrition are generally higher, such as South Asia, the Middle East, Sub-Saharan Africa, North Africa and the former Soviet Union.

“In the past ten years, the literature on food security has mostly focused on food quantity and calories, while much less attention has been devoted to nutrition security, especially nutrients other than dietary energy. Iron and zinc are two essential micronutrients we obtain from our diets, from both plant and animal sources. The World Health Organization considers dietary deficiencies of zinc and iron to be a global public health problem affecting about two billion people, most of whom get the largest share of these nutrients from crops as opposed to animals,” Nicola Cenacchi, Senior Research Analyst at the International Food Policy Research Institute and a co-author on the research article, tells NutritionInsight.Wheat, rice, corn, barley, potatoes, soybeans and vegetables will lose an average of 3 percent of their nutrition. 

While technological improvements and market effects will likely increase nutrient availability over current levels by 2050, the gains will be limited by the negative impacts of rising CO2 concentrations. Higher levels of CO2 boost photosynthesis and growth in some plants but reduce the concentration of key micronutrients. An average nutrient loss of 3 percent by 2050 is expected in wheat, rice, corn, barley, potatoes, soybeans and vegetables.

The international group of researchers used the IMPACT global agriculture sector model, along with data from the Global Expanded Nutrient Supply (GENuS) model and two data sets on the effects of CO2 on nutrient content in crops, to calculate the per capita availability of nutrients in 2050. The researchers say that the study is the most comprehensive synthesis of the impacts of elevated CO2 and climate change on the availability of nutrients in the global food supply to date.

“Looking forward, food fortification is an option, including vitamin and mineral fortification. Preventive supplementation is also a possible strategy. This could be encouraging national health systems to adopt supplementation policies, especially for vulnerable groups such as women in fertility age, children and the elderly. Additionally, it could be monitoring the nutrition status in the population and promotion of nutrition education in school systems and professional education programs. This all means more financial support to nutrition-supporting policies and interventions,” notes Cenacchi.

An unequal impact
The effects of reduced nutrition availability will not be felt evenly around the world. Many countries currently experiencing high levels of nutrient deficiency are also projected to be more affected by lower nutrient availability in the future. These diets are often more vulnerable to impacts stemming from temperature change, as well as to precipitation triggered by climate change.

“In general, people in low- and middle-income countries receive a larger portion of their nutrients from plant-based sources, which tend to have lower bioavailability than animal-based sources,” says Beach. Therefore, those with an already low nutrient intake are likely to be more vulnerable to deficiencies as crops lose their nutrients. These regions are often also expected to have the highest population growth and thus need the most nutrient-availability growth.

The nutrition loss of 12 percent in wheat could have an especially critical impact. “Wheat accounts for a large proportion of diets in many parts of the world, so any changes in its nutrient concentrations can have a substantial impact on the micronutrients many people receive,” adds Robert Beach, Senior Economist and Fellow at RTI International and lead author of the study.Regions with high population growth are the most in need of high-nutrient crop growth. 

It is likely that the largest decreases in wheat’s protein availability will be in places where wheat consumption is particularly high, including the former Soviet Union, Middle East and North Africa.

Those with micronutrient deficiencies suffer from a variety of physiological impairments and adverse impacts on the metabolism, immune system and cognitive development. This can lead to reduced resistance to infections, metabolic disorders, and delayed or impaired physical and psychomotor development.

“To offer a few specifics, iron deficiency affects about two billion people worldwide – not just in developing countries – and is the most prevalent nutrition problem in the world. It is associated with anemia, reduced learning and work capacity, increased maternal and infant mortality and low weight at birth. Zinc deficiency, which is high in developing countries, is associated with poor pregnancy outcomes, stunting and resistance to infectious diseases,” Cenacchi explains.

Additionally, while a sustainable diet is the subject of current analyses, there is not a clear consensus about what it actually involves. “There is some evidence that a diet based mostly on plant-sourced foods is better aligned with health nutrition outcomes and reduced environmental impacts in high-income and middle-income countries. In developing countries, access to animal-sourced foods is expected to grow and this growth will be important to provide balanced access to protein and to a variety of essential micronutrients,” Cenacchi concludes.

Another study earlier this year also showed that the planet’s eating habits must change drastically in order to be able to feed the future population. It also pointed out that food production and food waste must be improved.

By Katherine Durrell