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November 22nd, 2019 / Down to Earth

Global yields of rice, the world’s largest staple food crop, could plummet by as much as 40 per cent by 2100, affecting two billion people, a new study by Stanford University in the United States has said.

The plummeting of the yields would be caused by increasing temperatures. Moreover, changes in the chemistry of the soil due to increased temperatures would cause the rice grown to contain twice as much toxic arsenic than the rice that is consumed today, the study has added.

To arrive at their conclusions, the researchers grew a medium-sized rice variety in soil from California’s rice-growing region (Sacramento Valley). The experiment took place in greenhouses, the temperatures of which were based on a five degree Celsius temperature increase.

Carbon dioxide levels were increased to twice as much as what they are today. Both, the temperature of the greenhouse and the carbon dioxide level were based on estimates by the Intergovernmental Panel on Climate Change.

The scientists found that because of the higher temperatures, the inherent arsenic in the soil was destabilised and taken up by the rice plants. The arsenic went on to inhibit the absorption of nutrients and decrease the plants’ growth and development, causing yields to plummet by 40 per cent. Read more …