The one bright note in global warming is seemingly that higher carbon dioxide levels will make food crops grow faster. More crops should equal more food. But, as this feature article emphasises, the story is not that simple.

Initial tests have shown that plants grown in high carbon dioxide environments could be less nutritious — with lower protein levels and a different type of protein produced. Other scientists have found a drop in key micronutrients such as chromium, selenium and zinc in high carbon dioxide environments.

Mitigating these changes can involve increasing nitrogen levels to offset protein deficiency, although not all scientists agree on this.

What is clear is that there is very little research in this area and past studies have only looked at carbon dioxide concentrations of 550 parts per million, which is lower than levels predicted by the end of this century.