Food becoming more calorific but less nutritious due to rising carbon dioxide

Researchers noticed dramatic' changes in nutrients in crops, including drop in zinc and rise in lead

More carbon dioxide in the environment is making food more calorific but less nutritious - and also potentially more toxic, a study has found.

Sterre ter Haar, a lecturer at Leiden University in the Netherlands, and other researchers at the institution created a method to compare multiple studies on plants' responses to increased CO₂ levels. The results, she said, were a shock: although crop yields increase, they become less nutrient-dense. While zinc levels in particular drop, lead levels increase.