Rising carbon dioxide levels are not simply warming the planet and contributing to the global climate emergency. Research published on 14 November 2025 in Global Change Biology by Laura Scherer and colleagues at Leiden University revealed that elevated carbon dioxide alters the nutritional composition of crops by increasing caloric content while reducing key nutrients. This has been found across many widely consumed food plants.
The Carbon Dioxide Effect: How Plant Chemistry Shifts as the Atmosphere Changes
Rising carbon dioxide levels in the atmosphere are reshaping the chemistry of global food crops. The phenomenon is making them larger and more calorific but significantly less nutritious. Research reveals steep declines in minerals and proteins across dozens of staple foods.
Critical Findings
The researchers analyzed data from crops that compared growth under baseline carbon dioxide concentrations near 350 ppm with growth under elevated concentrations near 550 ppm. Results showed that rising carbon dioxide consistently increased carbohydrate production while reducing average nutrient density by 4.4 percent across multiple micronutrients.
Note that 43 crops were investigated. These include rice, wheat, potatoes, and tomatoes. Findings across these crops showed consistent shifts in chemical composition. The repeated pattern across fruits, vegetables, and grains demonstrates that the nutritional impacts of elevated carbon dioxide are broad, systematic, and likely to influence global food systems for decades.
Some nutrient declines were severe. Individual crops showed reductions as high as 38 percent in important elements and micronutrients such as zinc and iron. The content of vitamins linked to immune strength and cellular maintenance also declined. It is worth mentioning that these results represent a widespread pattern of nutrient loss across diverse plant species.
Protein levels in plants also fell. This comes from the fact that faster growth under elevated carbon dioxide levels outpaced the capacity of plant roots to absorb nitrogen from the surrounding soil environments. Plants require nitrogen to build amino acids. This limited uptake reduces protein formation. This effect strongly impacts staple grains such as wheat and rice.
Combined increases in carbohydrates and decreases in minerals and amino acids created a process called nutritional dilution. Each gram of plant tissue became less nutrient-dense but calorie-dense, even though total plant size increased. This translates to the fact that individuals must consume greater quantities of food to obtain the same levels of essential micronutrients.
The analysis also suggests initial signs that harmful elements or minerals such as mercury and lead may accumulate more readily under elevated carbon dioxide levels. Moreover, although additional investigation is needed, the possibility of increased toxic metal uptake raises significant concerns regarding long-term food safety and overall future nutritional security.
More Explanations
Current atmospheric carbon dioxide concentrations near 425 ppm place the world nearly halfway toward the study scenario used to project future nutrient declines. This indicates that the documented nutritional changes are not hypothetical future events but ongoing alterations already affecting crops in contemporary agricultural environments worldwide.
Elevated carbon dioxide levels in the atmosphere accelerate photosynthesis. This allows plants to produce greater quantities of sugars and starches. Note that this rapid carbohydrate accumulation expands total biomass, but the increase is not matched by proportional rises in minerals or amino acids, which creates an overall dilution of nutrients within plant tissues.
Faster growth under elevated carbon dioxide levels causes plants to require more nitrogen, yet roots cannot absorb nitrogen quickly enough to support balanced development. Because nitrogen enables amino acid formation, limited uptake reduces protein synthesis, resulting in lower protein concentrations across many staple crops under high carbon dioxide levels.
Mineral uptake declines because expanding tissues demand nutrients faster than roots and soil systems can supply them. Essential elements such as zinc and iron enter plant structures at slower rates, so they become proportionally scarcer, even as the physical size or mass of a particular plant increases substantially under stronger carbon-enriched conditions.
Changes in root physiology under elevated carbon dioxide may impair the movement of minerals from soil to plant tissues. Modified root structures, reduced transpiration, and altered water flow can collectively hinder nutrient transport, thus leaving rapidly growing crops with inadequate supplies of minerals for balanced nutritional composition.
The same issue also alters internal pathways by shifting energy allocation toward carbohydrate production. This reduces investment in micronutrient transport and amino acid formation. The imbalance results in crops that deliver higher caloric energy yet provide fewer essential nutrients required for immune function, metabolism, and long-term health.
FURTHER READING AND REFERENCE
- Ter Haar, S. F., van Bodegom, P. M., and Scherer, L. 2025. “CO2 Directly Impairs Crop Nutritional Quality.” Global Change Biology. 31(11): DOI: 1111/gcb.70568