Carbon Dioxide and Agricultural Yield: An Assemblage and Analysis of 430 Prior Observations¹

TLDR

Most studies were conducted in greenhouses or growth chambers, and open-field responses to elevated CO₂ may differ due to lower nutrient levels or higher light availability. The study evaluated the probable effect of increasing global atmospheric CO₂ concentration on agricultural yields. The authors compiled over 430 observations of 37 species from more than 70 reports spanning 64 years, primarily high-value crops, but findings should generalize to most global C3 and possibly C4 agriculture. The analysis indicates that doubling atmospheric CO₂ could raise yields by about 33% (99.9% CI 24–43%) despite data limitations.

Abstract

Abstract The probable effect of the increasing global atmospheric CO 2 concentration on agricultural yields was evaluated. More than 430 observations of the yield of 37 species grown with CO 2 enrichment were extracted from more than 70 reports published during the past 64 years. Most of the studies were performed in greenhouses or growth chambers. Open fields might respond less than greenhouses or growth chambers to increased CO 2 because nutrient levels in general world‐wide agriculture are lower than those in the indoor studies, or open fields might respond more because light levels are generally higher outside. The data also were dominated by high value crops, but results should be applicable to the three‐fourths of the world agriculture represented by the C 3 crops and possibly to the remaining C 4 crops as well. Keeping these limitations of the data in mind, the analysis showed that yields probably will increase by 33% (with a 99.9% confidence interval from 24 to 43%) with a doubling of atmospheric CO 2 concentration.