|Ainsworth, Elizabeth - Lisa|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/9/2009
Publication Date: 12/11/2009
Citation: Ainsworth, E.A., McGrath, J.M. 2009. Direct effects of rising atmospheric carbon dioxide on crop yields. In: Loebell, D. and Burke, M., editors. Climate Change and Food Security: Adapting Agriculture to a Warmer World. New York, NY: Springer. p. 109-132. Interpretive Summary:
Technical Abstract: Rising atmospheric carbon dioxide concentration (CO2) in this century will alter crop yield quantity and quality. It is important to understand the magnitude of the expected changes and the mechanisms involved in crop responses to elevated CO2 in order to adapt our food systems to the committed change in atmospheric CO2 and to accurately model future food supply. Free-Air CO2 Enrichment (FACE) allows for crops to be grown in their production environment, under fully open air conditions, at elevated CO2. Current best estimates for the response of the staple crops wheat, soybean and rice from FACE experiments are that grain yield will increase by 13% at 550ppm CO2. For the C4 species, sorghum and maize, grain yield is not expected to increase at elevated CO2 if water supply is adequate. Grain quality is adversely affected by elevated CO2. Protein content decreased by 10-14% in non-leguminous grain crops and concentrations of minerals, such as iron and zinc decreased by 15-30%. While these represent our best estimate of changes in crop yield quantity and quality, most studies have been done in temperate regions, and do not account for possible interactions of rising CO2 with other aspects of climate change, including increased temperature, drought stress and tropospheric ozone concentration.