How Do We Improve Crop Production in a Warming World?

Authors: Ainsworth, Elizabeth - Lisa; Ort, Donald

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2010
Publication Date: 9/9/2010
Citation: Ainsworth, E.A., Ort, D.R. 2010. How do we improve crop production in a warming world? Plant Physiology. 154:526-530.

Interpretive Summary: There is now overwhelming evidence that "business as usual" crop development will be insufficient to adapt crops over the wide range of growing regions that will be required to meet expanding global agricultural demand. Moving crops poleward seems an inevitable element of the multifaceted adaptation to increasing global temperatures that must be implemented, but it would be misleading to believe that this alone can maintain yields. For example migration of the North American Corn Belt into Canada vacates the high quality prairie soils for the less productive soils further north. And, in many important agricultural areas of the world, poleward migration is not possible such as the wheat belt of Australia in which an ocean lies to the south. Even adapting crops in the highest priority regions will require broad investment, the integration of new technologies with conventional selection-based breeding and with the coordinated involvement of public and private sectors of the agricultural enterprise. Current and future increases in temperature are perhaps the most significant and most urgent challenge for the adaption of crops to global change.

Technical Abstract: Global analysis of crop yields from 1981-2002, showed a negative response of wheat, maize and barley yields to rising temperature, costing an estimated $5 billion per year. An analysis of maize and soybean production in the northern Corn Belt region of the U.S. found that productivity was adversely affected by rising growing season temperatures from 1976-2006. The response of maize and soybean to temperature is also nonlinear, and the decline in yields above the temperature optimum is significantly steeper than the incline below it. Based on the non-linearity of the temperature response, U.S. maize and soybean yields were predicted to decrease by 30-46% before the end of the century under the IPCC scenario with the slowest warming trend. In addition to these historical trends, record crop yield losses were reported in 2003 when Europe experienced a heat wave with July temperatures up to 6°C above average and annual precipitation 50% below average. Such extreme events are not well characterized in the IPCC assessment simulations. Therefore, increased global temperatures and more frequent temperature extremes will greatly challenge agriculture in this century. Here we identify regional priorities and biological targets for adaptation of agriculture to rising temperature.