The effects of elevated atmospheric carbon dioxide [CO2] on micronutrient concentration, specifically iron (Fe) and zinc (Zn) in rice; a systematic review

Atmospheric carbon dioxide (CO2) levels have reached an all-time high, contributing to increased average temperature, more frequent and severe weather patterns, increasing sea levels, and the acidification of the ocean. Increasing levels of atmospheric CO2 are also showing a negative impact on staple food crops, such as rice. In addition to added heat stresses decreasing growth and productivity of rice crops, micronutrient concentration, specifically iron (Fe) and zinc (Zn), shows a significant decline when grown in elevated atmospheric CO2. This is likely to most significantly impact those who are already impoverished and living in a state of chronic food insecurity, thus further contributing to micronutrient deficiency diseases, also known as hidden hunger. A systematic review of the literature regarding micronutrient concentration, specifically Fe and Zn, in rice grains grown under elevated CO2 was conducted according to PRISMA guidelines for systematic reviews. Eight of the studies found met the required guidelines and were included in this review. While early studies were contradictory, later studies show a clear correlation between elevated atmospheric CO2 and decreased Fe and Zn concentrations. The mechanism of action remains unclear at this time, and more research is needed into ways to mitigate these effects moving forward.