How is CO sub(2) affecting yields and technological progress? A statistical analysis

• Published in: Climatic change Vol. 124; no. 4; pp. 747 - 762
• Main Authors: Attavanich, Witsanu, McCarl, Bruce A
• Format: Journal Article
• Language: English
• Published: 01.06.2014
• Subjects: Atmospherics; Carbon dioxide; Climate; Corn; Cotton; Crops; Soybeans; Wheat
• ISSN: 0165-0009; 1573-1480
• DOI: 10.1007/s10584-014-1128-x

This paper analyzes the impact of climate, crop production technology, and atmospheric carbon dioxide (CO sub(2)) on current and future crop yields. The analysis of crop yields endeavors to advance the literature by estimating the effect of atmospheric CO sub(2) on observed crop yields. This is done using an econometric model estimated over pooled historical data for 1950-2009 and data from the free air CO sub(2) enrichment experiments. The main econometric findings are: 1) Yields of C3 crops (soybeans, cotton, and wheat) directly respond to the elevated CO sub(2), while yields of C4 crops (corn and sorghum) do not, but they are found to indirectly benefit from elevated CO sub(2) in times and places of drought stress; 2) The effect of technological progress on mean yields is non-linear; 3) Ignoring atmospheric CO sub(2) in an econometric model of crop yield likely leads to overestimates of the pure effects of technological progress on crop yields of about 51, 15, 17, 9, and 1 % of observed yield gain for cotton, soybeans, wheat, corn and sorghum, respectively; 4) Average climate conditions and climate variability contribute in a statistically significant way to average crop yields and their variability; and 5) The effect of CO sub(2) fertilization generally outweighs the effect of climate change on mean crop yields in many regions resulting in an increase of 7-22, 4-47, 5-26, 65-96, and 3-35 % for yields of corn, sorghum, soybeans, cotton, and wheat, respectively.