Anticipated burden and mitigation of carbon-dioxide-induced nutritional deficiencies and related diseases: A simulation modeling study

Abstract

BackgroundRising atmospheric carbon dioxide concentrations are anticipated to decrease the zinc and iron concentrations of crops. The associated disease burden and optimal mitigation strategies remain unknown. We sought to understand where and to what extent increasing carbon dioxide concentrations may increase the global burden of nutritional deficiencies through changes in crop nutrient concentrations, and the effects of potential mitigation strategies.Methods and findingsFor each of 137 countries, we incorporated estimates of climate change, crop nutrient concentrations, dietary patterns, and disease risk into a microsimulation model of zinc and iron deficiency. These estimates were obtained from the Intergovernmental Panel on Climate Change, US Department of Agriculture, Statistics Division of the Food and Agriculture Organization of the United Nations, and Global Burden of Disease Project, respectively. In the absence of increasing carbon dioxide concentrations, we estimated that zinc and iron deficiencies would induce 1,072.9 million disability-adjusted life years (DALYs) globally over the period 2015 to 2050 (95% credible interval [CrI]: 971.1–1,167.7). In the presence of increasing carbon dioxide concentrations, we estimated that decreasing zinc and iron concentrations of crops would induce an additional 125.8 million DALYs globally over the same period (95% CrI: 113.6–138.9). This carbon-dioxide-induced disease burden is projected to disproportionately affect nations in the World Health Organization’s South-East Asia and African Regions (44.0 and 28.5 million DALYs, respectively), which already have high existing disease burdens from zinc and iron deficiencies (364.3 and 299.5 million DALYs, respectively), increasing global nutritional inequalities. A climate mitigation strategy such as the Paris Agreement (an international agreement to keep global temperatures within 2°C of pre-industrial levels) would be expected to avert 48.2% of this burden (95% CrI: 47.8%–48.5%), while traditional public health interventions including nutrient supplementation and disease control programs would be expected to avert 26.6% of the burden (95% CrI: 23.8%–29.6%). Of the traditional public health interventions, zinc supplementation would be expected to avert 5.5%, iron supplementation 15.7%, malaria mitigation 3.2%, pneumonia mitigation 1.6%, and diarrhea mitigation 0.5%. The primary limitations of the analysis include uncertainty regarding how food consumption patterns may change with climate, how disease mortality rates will change over time, and how crop zinc and iron concentrations will decline from those at present to those in 2050.ConclusionsEffects of increased carbon dioxide on crop nutrient concentrations are anticipated to exacerbate inequalities in zinc and iron deficiencies by 2050. Proposed Paris Agreement strategies are expected to be more effective than traditional public health measures to avert the increased inequality.

The Mismatch between Anthropogenic CO2 Emissions and Their Consequences for Human Zinc and Protein Sufficiency Highlights Important Environmental Justice Issues

“…These findings build on previous modeling work [14,15] to quantify the inequalities in the nutritional impacts of climate change and add to our understanding of climate justice. This work shows that the countries and people that have contributed the least to global rising CO 2 emissions are likely to be at the greatest risk of increased zinc and protein inadequacy and underscores the need for substantial greenhouse gas mitigation and adaptation efforts and also greater attention to redressing such injustices across countries.…”

“…A full description of their methods may be found in the original publication, but the following is a brief summary [14]. Previous studies [10][11][12]14,15] have found that an elevated CO 2 concentration of 550 ppm can reduce the zinc and protein content of many staple crops by up to 17% relative to ambient conditions of 363-386 ppm. Based on our current global emissions trajectory, we will reach 550 ppm CO 2 by roughly mid-century [13].…”

“…Modeling studies examining the global health implications of these changes found that by 2050 the decreased zinc content in foods could put 175 million people globally at new risk of zinc deficiency and 122 million at new risk of protein deficiency [14]. Other models have estimated that the decreased crop zinc and iron concentrations attributable to elevated atmospheric CO 2 concentrations could lead to an additional 125.8 million disability-adjusted life years globally from 2015 to 2050 [15]. Inadequate zinc intake in children is associated with pneumonia, malaria, and diarrheal disease [16], and may contribute to low birthweight and altered immunity and metabolic status among offspring when occurring prior to or during pregnancy [17].…”

Rising Atmospheric CO2 Lowers Concentrations of Plant Carotenoids Essential to Human Health: A Meta‐Analysis

“…C3 plants make up >95% of plant species, provide >75% of calories to humans, and include rice, wheat, and nearly all crop fruits and vegetables . CO 2 ‐induced declines of 5–15% in protein, iron, and zinc in edible parts of C3 crops have been reported, and are projected to waste over 125 million disability‐adjusted life years (DALYs) by 2050 …”

Crops For the Future (CFF): an overview of research efforts in the adoption of underutilised species

“…The need for a Centre such as CFF arises for several reasons but not least because human food systems are currently dominated by four crops-rice, wheat, maize and soybean-of which the three cereals provide over 50% of plant-based human food (IPES-Food 2016). In a warming world with more extreme weather, reliance on such a limited number of crops poses major challenges to food and nutritional security (Kahane et al 2013;Weyant et al 2018). Furthermore, existing deficiencies of key vitamins and minerals pose a serious constraint to human health and economic development (GLOPAN 2016).…”