Abstract:CO2 concentrations are presently elevated and are expected to continue increasing in the future, resulting in global warming and climate change. Heavy metal pollution is also a serious issue, particularly in copper mining areas. While there have been results published on each of these issues individually, these have been limited to single factors. Consequently, there have been limited data on the comprehensive combined effects of climate change and heavy metal pollution (for example, combined copper and cadmium pollution in soils). This study aimed to investigate the effects of elevated CO2 levels on the uptake of Cu and Cd in rice varieties grown in soil contaminated with both of these pollutants. The study also considered concentrations of four mineral elements (Fe, Zn, Ca, and Mn), together with potential hazards of Cd contamination in rice to human health. A pot experiment was conducted in an open top chamber at two CO2 concentration levels, i.e., normal level of ambient concentration (380 μmol/mol) and an elevated concentration level (760 μmol/mol). Five different varieties of rice were selected for purposes of this experiment. The results showed a reduction in dry biomass production of rice grown in soil subject to low-level contamination from multiple pollutants; conversely, dry biomass production was enhanced under conditions of elevated CO2 in soils with high-level contamination from multiple pollutants. Cu concentrations of the five indica rice grains decreased by 4.75%-24.49% in low-level multi-contaminated soils but incr2eased by 6.6%-40.37% in high-level multi-contaminated soils with elevated CO2 concentrations. Total Cu uptake in rice decreased at both contamination levels under elevated CO2 concentrations. Similarly, Cd concentrations and total Cd uptake of the San Xian-you (974) grain declined significantly at both levels of contamination, with decreases in Cd content of 43.44%, 57.95%, and 47.01%, 60.56%, respectively. While Cd concentrations and total Cd uptake of the four rice varieties all increased, the range of increase was between 25.42%-103.07% and 12.62%-20.05%, respectively. The total uptake of Cd and Cu of the four rice varieties was higher in high-level multi-contaminated soils under elevated and ambient CO2 treatments, when compared to soils subject to a low level of contamination. There were significantly different effects on concentrations of Fe, Zn, Ca, and Mn in the five indica rice varieties of elevated CO2 concentrations. Zn concentrations of the San Xian-you (974) grain increased significantly in both low-level and high-level multi-contaminated soils with elevated CO2 concentrations. Similarly, Mn concentrations of San Xiang-you (974) and Jinyou-463 increased significantly at both contamination levels under elevated CO2 conditions. Cd concentrations in the Jinyou-463 grain exceeded food hygienic standards (Cd < 0.2 mg/kg) under both elevated and ambient CO2 treatments, at both levels of contamination. Cd concentrations of Sanxiangyou-974 also exceeded food hygienic standards under ambient CO2 levels. At both contamination levels, the target hazard quotient (THQ) for Cd of Jinyou-463 and Sanxiangyou (974) exceeded 1, indicating that the consumption of both rice varieties would lead to high potential human health risks.