Climate change has suppressed food production around the world during the past three decades, according to modelling work. Global maize (corn) production, for example, is estimated to be 3.8% lower than it would have been if Earth were not warming.

David Lobell at Stanford University in California and his co-authors analysed links between national yields and temperature and precipitation trends from 1980 to 2008. They estimate that, despite the fertilizing effect of increased carbon dioxide in the atmosphere, wheat production has dropped by 2.5%. However, thanks to the CO2 boost, yields of rice are up by 2.9% and soya beans by 1.3%. The United States, which produces about 40% of the world's soya and maize, has so far been unaffected because its crop-growing regions haven't warmed much in summer.

Overall, the changes wrought by the warming climate during the study period bumped up food commodity prices worldwide by about 6.4%, the authors suggest.

Science doi:10.1126/science.1204531 (2011)