Irrigation of rice paddies leads to even greater accumulation of arsenic in soils. “We found that rice plants increasingly absorb soil arsenic with rising temperature and atmospheric CO2 content,” Eva Marie Muehe says. Arsenic damages the formation of rice grains, further reducing yields already diminished by the conditions of global warming.

Using greenhouse studies and based on earlier simulation models, the researchers showed that global warming causes a drop of 16 per cent in yields of the Californian rice variety M206 alone. “If we include the increased availability of arsenic in soils, we arrive at a decrease in yield of 42 per cent,” Muehe says. This means that forecasts of future rice yields are significantly too high. Future rice production will also contain more arsenic, which is toxic for humans. Ongoing intake of significant quantities of arsenic can lead to skin lesions, cancer, exacerbation of lung diseases and even death.

The researcher intends to cooperate with other research teams to further improve the models for future rice production, taking into account the effect of pollutants such as arsenic.