Almost two billion people worldwide have too little zinc and iron in their diet, which can cause problems such as anaemia, especially in children.
According to a new study published in Nature, climate change may significantly increase the problem in the coming decades.
The authors say that higher concentrations of carbon dioxide in the atmosphere will reduce the amount of these nutrients in the most common crops such as rice, wheat and legumes. This means that people whose diets are based on these crops will get less zinc and iron despite eating the same quantity of food.
The scientists call for more research to develop crop strains that are more resistant to higher carbon dioxide levels or that are naturally richer in iron and zinc.